A new statistical model of wave heights based on the concept of wave breaking critical zone

Iris -aperture stop 虹膜孔徑光珊retina 视网膜Color Blind 色盲weak color 色弱Myopia -near-sighted 近视Sensitivity to Light 感光灵敏度boost 推进lag behind 落后于Hyperopic -far-sighted 远视Dynamic Range 动态范围critical fusion frequency 临界融合频率CFF 临界闪变频率visual sensation 视觉Chromaticity Diagram 色度图Color Temperature 色温HSV Model 色彩模型(hue 色度saturation 饱和度value 纯度CIE Model 相干红外能量模式Complementary Colors 补色Bar Pattern 条状图形Heat body 热稠化approximate 近似violet 紫罗兰Body Curve 人体曲线Color Gamut 色阶adjacent 邻近的normal illumination 法线照明Primary colors 红黄蓝三原色Color saturation 色饱和度Color Triangle 颜色三角Color Notation 颜色数标法Color Difference 色差TV Signal Processing 电视信号处理Gamma Correction 图像灰度校正Conversion Tables 换算表out of balance 失衡wobble 摇晃back and forth 前后clear (white) panel 白光板vibrant 震动fuzzy 失真quantum leap 量子越迁SVGA (800x600)derive from 起源自culprit 犯人render 呈递inhibit 抑制,约束stride 大幅前进blemish 污点obstruction 障碍物scratch 刮伤substance 物质实质主旨residue 杂质criteria 标准parameter 参数adjacent 邻近的接近的asynchrony 异步cluster 串群mutually 互助得algorithm 运算法则Chromatic Aberrations 色差Fovea 小凹Visual Acuity 视觉灵敏度Contrast Sensitivity 对比灵敏度Temporal (time) Response 反应时间rendition 表演,翻译animation 活泼又生气ghost 重影Parallax 视差deficient 缺乏的不足的Display panel 显示板NG.( Narrow Gauge) 窄轨距dichroic mirror 二色性的双色性的Brewster Angle 布鲁斯特角Polarized Light 极化光Internal reflection 内反射Birefringence 双折射Extinction Ratio 消光系数Misalignment 未对准Quarter Waveplates 四分之一波片blemish 污点瑕疵Geometric 几何学的ripple 波纹capacitor 电容器parallel 平行的他tantalum 钽(金属元素) exsiccate 使干燥exsiccate 油管,软膏furnace 炉子镕炉electrolytic 电解的,由电解产生的module 模数analog 类似物out of the way 不恰当pincushion 针垫拉lateral 侧面得rectangle 长方形fixture 固定设备control kit 工具箱DVI connector DVI 数局线Vertical 垂直的horizontal 水平的interlace 隔行扫描mullion 竖框直楞sawtooth 锯齿toggle 套索钉keypad 数字按键键盘tangential 切线diagnostic tool 诊断工具sagittal direction 径向的cursor position 光标位置3Yw'/#p3'ray aberration 光线相差weighting factor 权种因子variables 变量for now 暂时,目前.眼下check box 复选框Airy disk 艾里斑exit pupil 出［射光］瞳optical path difference 光称差with respect to 关于diffraction limited 衍射极限wavefront aberration 波阵面相差spherical aberration 球面象差paraxial focus 傍轴焦点chromatic aberration 象差local coordinate system 局部坐标系统coordinate system 坐标系orthogonal 直角得,正交的conic sections 圆锥截面account for 解决,得分parabolic reflector 拋物面反射镜radius of curvature 曲率半径spherical mirror 球面镜geometrical aberration 几何相差incident radiation 入射辐射global coordinate 总体坐标in terms of 根据按照reflected beam 反射束FYI=for your information 供参考Constructive interference 相长干涉phase difference 相差achromatic singlet 消色差透镜Interferometer 干涉仪boundary constraint 边界约束,池壁效应radii 半径Zoom lenses 变焦透镜Beam splitters 分束器discrete 不连续的,分离的objective/eye lens 物镜/目镜mainframe 主机rudimentary 根本的,未发展的photographic 照相得摄影得taxing 繁重的,费力得algebra 代数学trigonometry 三角学geometry 几何学calculus 微积分学philosophy 哲学lagrange invariant 拉格朗日不变量spherical 球的field information 场信息Standard Lens 标准透镜Refracting Surface 折射面astigmatism 散光HDTV 高清晰度电视DLV ( Digital Light Valve) 数码光路真空管，简称数字光阀diffraction grating 衍射光珊field angle 张角paraxial ray trace equations 近轴光线轨迹方称back focal length 后焦距principal plane 主平面vertex 顶点,最高点astigmatism 散光,因偏差而造成的曲解或错判medial 中间的,平均的variance 不一致conic 圆锥的,二次曲线field of view 视野collimator 瞄准仪convolution 回旋.盘旋,卷积fuzzy 失真,模糊aberrated 异常的asymmetry不对称得indicative 可表示得parabolic 拋物线得suffice 足够,使满足specification 规格,说明书straightforward 易懂的,直接了当的,solidify 凝固,巩固. Constraints 约束,限制metrology 度量衡field coverage 视场,视野dictate 口述, 口授, 使听写, 指令, 指示, 命令, 规定irradiance 发光, 光辉,辐照度aerial 空气得,空中得halide 卤化物的monochromatic 单色的,单频的polychromatic 多色的aspherical 非球面的spherical 球面的alignment 列队,结盟power( 透镜) 放大率equiconvergence 同等收敛EFL(effective focal length) 有效焦距workhorse 广为应用的设备biconvex 两面凸的global optimization 整体最优化concave 凹得,凹面得cylindrical 圆柱得solid model 实体模型Modulation Transfer Function 调制传递函数in the heat of 在最激烈的时候protocol 协议,规定triplet 三重态sanity 心智健全zinc 锌,涂锌的selenide 硒化物,硒醚miscellaneous 各色各样混在一起, 混杂的, 多才多艺的versus 与... 相对polynomial 多项式的coefficient 系数explicit function 显函数" wYgi%distinct 清楚的,截然不同的emanate 散发, 发出, 发源rudimentary 根本的,未发展的intersection 角差点PRTE=paraxial ray trace equation 旁轴光线轨迹方程achromats 消色差透镜cardinal points 基本方位separations 分色片dashed 虚线blow up 放大overlay 覆盖, 覆盖图multiplayer 多层的humidity 湿度float glass 浮法玻璃square one 出发点,端点square up to 准备开打, 坚决地面对reflecting telescope 反射式望远镜diagnostic tools 诊断工具Layout plots 规划图Modulation transfer function 调制转换功能FFT 快速傅里叶变换Point spread function 点传播功能wavelength 波长angle 角度absorption 吸收system aperture 系统孔径lens units 透镜单位wavelength range 波长范围singlet lens 单业透镜spectrum 光谱diffraction grating 衍射光栅asphere 半球的LDE=Lens data editor Surface radius of curvature 表面曲率半径surface thickness 表面厚度material type 材料种类semi-diameter 半径focal length 焦距aperture type 孔径类型aperture value 孔径值field of view 视场microns 微米F, d, and C= blue hydrogen, yellow helium, red hydrogen lines, primary wavelength 主波长sequential mode 连续模式object surface 物表面The front surface of the lens 透镜的前表面stop 光阑The back surface of the lens 透镜的后表面The image surface 像表面symmetric 相对称的biconvex 两面凸的The curvature is positive if the center of curvature of the surface is to the right of the vertex. It is negative if the center of curvature is to the left of the vertex. 如果曲率中心在最高点的右边,曲率值为正, 如果曲率中心在最高点的左边,则曲率为负image plane 像平面Ray Aberration 光线相差tangential direction 切线方向sagittal direction 径向paraxial focus 旁轴的Marginal 边缘的spherical aberration 球面像差Optimization Setup 最优化调整variable 变量mathematical sense 数学角度MFE= Merit Function Editor, Adding constraints 增加约束focal length 焦矩长度operand 操作数the effective focal length 有效焦矩primary wavelength 主波长initiate 开始spot diagram 位图表Airy disk 艾里斑axial chromatic aberration 轴向色差with respect to 关于至于exit pupil 出射光瞳OPD=optical path difference 光学路径差diffraction limited 衍射极限chromatic aberration 色差chromatic focal shift 色焦距变换paraxial focus 傍轴焦点axial spherical aberration 轴向球差(longitudinal spherical aberration 纵向球差: 沿光轴方向度量的球差)lateral spherical aberration垂轴球差(在过近轴光线像点 A '的垂轴平面内度量的球差)coma 、comatic aberration 彗差meridional coma 子午彗差sagittal coma 弧矢彗差astigmatism 像散local coordinate system 本地坐标系统meridional curvature of field 子午场曲sagittal curvature of field 弧矢场曲decentered lens 偏轴透镜orthogonal 直角的垂直的conic section 圆锥截面account for 说明,占有, 得分stigmatic optical system 无散光的光学系统Newtonian telescope 牛顿望远镜parabolic reflector 抛物面镜foci 焦距chromatic aberration, 色差superpose 重迭parabola 抛物线spherical mirror 球面镜RMS=Root Mean Square 均方根wavefront 波阵面spot size 光点直径Gaussian quadrature 高斯积分rectangular array 矩阵列grid size 磨粒度PSF=Point Spread Function 点扩散函数FFT=Fast Fourier Transform Algorithm 快速傅里叶变换Cross Section 横截面Obscurations 昏暗local coordinates 局部坐标系统vignette把…印为虚光照Arrow key键盘上的箭头键refractive折射reflective反射in phase同相的协调的Ray tracing 光线追迹diffraction principles 衍射原理order effect 式样提出的顺序效果energy distribution 能量分配Constructive interference 相长干涉dispersive 色散的Binary optics 二元光学phase advance 相位提前achromatic single 消色差单透镜diffractive parameter 衍射参数Zoom lenses 变焦透镜Athermalized lenses 绝热透镜Interferometers 干涉计Beam splitter 分束器Switchable component systems 可开关组件系统common application 通用symmetry 对称boundary constraint 边界约束multi-configuration (MC) MC Editor (MCE) perturbation 动乱,动摇index accuracy 折射率准确性index homogeneity 折射率同种性index distribution 折射率分配abbe number 离差数Residual 剩余的Establishing tolerances 建立容差figure of merit 质量因子tolerance criteria 公差标准Modulation Transfer Function （MTF）调制传递函数boresight 视轴，瞄准线Monte Carlo 蒙特卡洛Tolerance operands 误差操作数conic constant ]MC1"{_qT 圆锥常数astigmatic aberration 像散误差Mechanical tilt 机械倾斜，机械倾角Tolerance Data Editor （TDE）公差资料编辑器compensator 补偿棱镜estimated system performance 预估了的系统性能iteratively 反复的，重迭的statistical dependence 统计相关性sequential ray trace model 连续光线追迹模型imbed 埋葬，埋入multiple 多样的，多重的，若干的Non-Sequential Components 不连续的组件Corner cube 角隅棱镜，三面直角透镜Sensitivity Analysis 灵敏度分析Faceted reflector 有小面的反射镜emit 发射，发出nest 嵌套overlap 交迭outer lens 外透镜brute force 强力seidel 像差系数aspect ratio 长宽比MRA 边缘光线角MRH 边缘光线高度asynchronous 不同时的,异步Apodization factor 变迹因子hexapolar 六角形dithered 高频脉冲衍射调制传递函数（DMTF ），衍射实部传递函数（DRTF ），衍射虚部传递函数（DITF ），衍射相位传递函数（DPTF ），方波传递函数（DSWM ）logarithmic 对数的parity 奇偶% Uc,I e longitudinal aberrations 纵向像差赛得系数：球差（SPHA , SI）,彗差（COMA , S2）,像散（ASTI , S3）, 场曲（FCUR , S4）,畸变（DIST , S5）,轴向色差（CLA , CL）和横向色差（CTR , CT）•横向像差系数：横向球差（TSPH）横向弧矢彗差（TSCO）横向子午彗差（TTCO）横向弧矢场曲（TSFC）横向子午场曲（TTFC ）,横向畸变（TDIS ）横向轴上色差（TLAC ）纵向像差系数：纵向球差（LSPH ）,纵向像散（LAST ）,纵向匹兹凡场曲（LPFC ）,纵向弧矢场曲（LFCS ）,纵向子午场曲（LFCT ）和纵向轴上色差（LAXC ）,横向像散（TAST）,横向匹兹凡场曲（TPFC ）纵向弧矢场曲（LSFC）纵向畸变（LDIS）波前系数：球差（W040 ）,彗差（W131 ），像散（W222 ）,匹兹凡场曲（W220P ），畸变（W311 ）,轴向色离焦项（W020 ）, 轴向色倾斜（W111）,弧矢场曲（W220S ）,平均场曲（W220M ）,子午场曲（W220T ）•彗差comatic aberration 子午彗差meridional coma 弧矢彗差sagittal coma 锤形优化（Hammer Optimization）评价函数列表（Merit Function Listing）公差汇总表（Tolerance Summary）套样板（Test Plate Fitting）镜头库（Lens Catalogs）等双凸/ 等双凹（equiconvex/equiconcave）和双凸/ 双凹（ biconvex/biconcave）。

A new standard height gage providing reliable and smart measurementNo. 570-402No. 570-404Measuring range 0~300 mmMeasuring range0~600 mmNo. 570-413Measuring range0-18" / 0~450 mmMain functions and featuresThe design of the case allows for easy installation of U-WAVE (optional), which enables wireless transmission of measurement data, promoting smarter use of data in manufacturing sites.Helps transform manufacturing sites into The handle for moving the slider enables smooth vertical movement. In addition, the highly rigid pillars and large clamp levers provide smooth and reliable workability.Supports smooth and reliable measurement operationsThe LCD is larger to improve the visibility of numbers and other displays. In addition, the number of operation switches have been reduced to a three-button system and have enlarged the DATA/HOLD button to make it easier to press, ensuring more reliable operability.The holder arm and clamp are optional .Supports high quality manufacturing through efficient measurementBy placing the body and Dial Test Indicator on a flat surface plate, even complex shapes can be measured accurately and easily. In addition, the smooth movement across the surface plate provides excellent workability.Special featuresActual sizeActual sizeThe LCD screen has been enlarged and the typeface changed to bold,enhancing visibility over previous models.* T he U-WAVE needs to be fixed in place using adouble-sided fastener/tape.10 mm12 mmT he Absolute (ABS) origin settingfunction memorizes a surface plate, etc. asthe absolute origin.T he INC (incremental) measurementfunction allows the setting of the origin atany position.T he DATA button activates data outputwhen the data output option is connected.T he HOLD function retains displayed valueswhen no output option is connected.Other functionsT he Measurement data output terminal can be used to buildstatistical process management systems and measurement systems. Ensures high visibility and improves work efficiencySupports smart data collection and managementSmooth operation and settingsThe 12 mm high character display—20% bigger than theprevious model—makes it easier to read the measured values.The 3-button operation makes it consistent with otherMitutoyo devices. And when used together with U-WAVE, itmakes data management operations easy.Large LCD (liquid crystal display)We have made it even easier to set up the"U-WAVE" wireless measurement datacommunication system, which makesmeasurement data entry easier and morereliable.The reviewed design makes installationfaster and easier.Links with U-WAVE*Three-button operationNew modelPrevious model570-414Option LineupA ttached to both the workpiece *1 and height gage *2 when measuring heights using a height gagewith a scriber, the contact sensor is a convenient detector that lights up when the scriber touches the workpiece.*1 Conductive workpieces only. *2 Attach to a conductive part.M agnet is incorporated. U se with a granite surface plate (precision stone surface plate). (For details, refer to our website.) P ower supply: PR44 (air battery) × 2T he batteries for monitoring are not included with the product and must be purchased separately.A llows quick measurement of center-to-center distance between holes. M easurable hole diameters: 1 to 38 mm C ross-section of mounting bar: 9×9 mmNo. 900872No. 900581: With inch-type holding bar (0.25x0.5 in cross-section)No. 951144: With metric-type holding bar (9x9 mm cross-section )No. 902053 (metric)No. 900322 (inch)No. 953639 (inch)No. 953638 (metric)*For mounting test indicators, etc.*For mounting test indicators, etc.Optional accessoriesContact SensorA ttaches to a height gage for measuring groove and hole depth. Minimum measurable hole diameter: 5.5 mm M aximum distance from the bottom of the holding bar to the contact point: 80 mm (metric type), 2.95 in (inch type) D ial indicator contact points are usable. (For details, refer to our website.) H olding bar length: 100 mmNo. 900878: With inch-type holding bar (0.25x0.5 in cross-section)No. 900764: With metric-type holding bar (9x9 mm cross-section)Depth Gage AttachmentSwivel clamp(with dovetail groove)*Holding bar*Center ProbeWindows 2000 SP4, Windows XP SP2 or later, Windows Vista, Windows 7, Windows 8, Windows 8.1, Windows 10 Operating environmentUSB-ITPAK V2.1A USB dongle must be connected to the PC running the software.T T T Digimatic Gage/PC Data Input DeviceUSB Input ToolI nterface used to export calculation results to spreadsheet software on a computer via a USB cable. Calculation results (values) can be exported in one operation.USB Direct Input Tool No. 06AFM380F USB-ITN-FUSB Keyboard Signal Converter Type No. 264-016-10IT-016UOne Required 1m No. 9053382m No. 905409Note: O ne of the cables on the upper right (sold separately) isrequired to connect the testing machine to the IT-016U.Wireless Measurement Data Communication SystemU-WAVEU wireless communication.E U-WAVE-R No. 02AZD810DWith USB 2.0 cable (1 m)Sensor SystemsTest EquipmentDigital Scale and DRO SystemsSmall Tool Instruments and Data Managementbasis.Mitutoyo America Corporation One Number to Serve You Better 1-888-MITUTOYO (1-888-648-8869)M 3 Solution Centers:Aurora, Illinois (Headquarters)Boston, Massachusetts Charlotte, North Carolina Cincinnati, Ohio Detroit, Michigan Los Angeles, California Seattle, Washington Houston, Texas© 2022 M i t u t o y o A m e r i c a C o r p o r a t i o nFind additional product literature and our product catalogNote: All inform ation regarding our products, and in particular the illustrations, drawings, dim ensional and perform ance data contained in this printed matter as well as other technical data are to be regarded as approximate average values. We therefore reserve the right to make changes to the corresponding designs. The stated standards, similar technical regulations, descriptions and illustrations of the products were valid at the time of printing. In addition, the latest applicable version of our General Trading Conditions will apply. Only quotations submitted by ourselves may be regarded as definitive. Specifications are subject to change without notice.Mitutoyo products are subject to US Export Administration Regulations (EAR). Re-export or relocation of our products may require prior approval by an appropriate governing authority.Trademarks and RegistrationsDesignations used by companies to distinguish their products are often claimed as trademarks. In all instances where Mitutoyo Am erica Corporation is aware of a claim, the product nam es appear in initial capital or all capital letters. The appropriate companies should be contacted for more complete trademark and registration information.0422 • FOR WEB ONLY • April 2022。

Generate mash 生成网格general一般Graphs 图cable dynamics缆索动力学struct mass 结构质量structure 结构acceleration due to gravity 重力加速度water density 水密度coord 坐标new default mass inertia 新默认的质量惯性version 版本beam 梁MESH FROM LINES PLANS/SCALING 网状线图则/缩放Monitor 显示器Frequency 频率approximate time left 大约剩余时间matrix calculation 矩阵计算matrix assembly 矩阵组装post processing 后处理quadrant 象限Modal visualization 模态可视化Pressure contours 压力等值线Sequence 序列Scaling 缩放lines plan 线图ship bending/shear 船的弯曲和剪切splitting forces 分裂力hardcopy 硬拷贝postscript 后记copy to clipboard 复制到剪贴板wave parameters 波参数wave amplitude 波振幅diffracted wave surface 衍射波面binary file（二进制文件）hydrodynamic database（流体力学数据库）Slopes斜坡RAO Motion 表示考虑了船体的运动Ref. Height(Z) above SWL（平均湿水面）free floating raos自由浮动响应steady drift force近场法的平均漂移力radiation damping辐射阻尼radians弧度ratio比率Characteristcs 空间分布特征Mooring 系泊停泊static equilibrium position 静态平衡位置dynamic 动态dynamic stability characteristics 稳定特性static equilibrium configuration 静平衡配置manual 手册component 组件hydrostatic stiffness properties 静刚度特性specify 指定mooring configuration 系泊配置modeling 建模format 格式capabilities 能力loop 循环sea（wave）spectra 波浪普spectrum谱frequency domain 频域visualisation可视化submerge淹没the cut waterplane淘汰水线locations of the centre of buoyancy浮心的位置fixed reference axes固定参考坐标系integrals 积分the displaced volume of fluid排水体积symmetric对称asymmetri c不对称vertical line垂直线horizontal水平的equilibrium平衡the detailed geometry of 详细的几何形状tubular（tube）管状drag coefficient 阻尼系数characteristic drag diameter阻尼特征直径(即柱体直径) intertia coefficient 惯性系数fluid velocity水流速度area of cross section截面面积fluid density 流体密度acceleration加速度可简写为accelacceleration due to gravity重力加速度account描述variation变化components机器设备组成部分分量discs底面圆arbitrarily任意diffraction/radiation wave force 衍射/辐射波浪力mean wave drift force 平均波浪（漂移）力variable wave drift force变化波浪力interactive fluid loadingsingular degrees of freedom自由奇异度global stiffness matrix全局刚度矩阵structural articulation and constraints结构的连接和约束thruster force推进力magnitude巨大的weightless elastic hawser失重弹性锚链hull drag force船体阻力drag force阻力damping force阻尼力intertia force惯性力buoyancy force浮力incident wave 入射波diffraction force衍射力Froude Krylov force弗劳德克雷洛夫力Second order drift force二阶漂移力global environmental parameters环境参数additional linear stiffness附加线性刚度classification分类geometric and material date几何和材料数据assemble装配structural mass结构质量mass inertia质量惯性coordinates坐标node point节点corresponding drift force相应的漂移力added mass and damping matrices附加质量和阻尼矩阵property属性财产preliminary初步的input format输入格式instruction指令misinterpreted误解interpretation解释hydrostatic model静水模型hydrodynamic model水动力学模型consistent set of units符合规定的单位monochromatic waves单色波radiation damping matrix辐射阻尼矩阵the range of….的范围alteration改造变动omitted省略mandatory强制性的constant magnitude常数量级deactivated停用使不活动displacement取代，位移initial estimate初步估计iteration迭代drag scale factor阻力比例因子Local Reynolds Number局部雷诺数convergence收敛合流graphics图形trajectory轨迹tabulation制表表格topology拓扑category类别amplitude squared振幅的平方surge纵荡sway横荡heave垂荡升沉yaw偏航首摇roll横摇pitch纵摇horizontal planar motion水平面内运动approach方法asymptotic value渐进值hydrodynamic parameters水动力参数cable/line mooring configuration电缆/线系泊配置uniform 制服均值superimposed叠加draught吃水translation 水平移动翻译rotation 旋转eigenvalue特征值mass inertia质量惯性with respect to关于stretch拉伸extension扩展范围vessel船只容器导管symmetry对称性utilise利用rectangular矩形planar平面PMAS质点Beneath下方底下be proportional to与..成正比asymptotes渐近线finite value asymptotes有限值渐进approximation近似empirical经验centroid质心radians弧度prefix词头前缀diagnostics诊断sequence序列options选项amp 放大器range范围contours轮廓tick cycle to animate (cycle 周期、循环animate 动画) wave elevation 波高cursor光标sequence序列排序socket插座插口universal joint万向节（通用连接）brackets括弧cog重心（center of gravity的简写）stiffness matrix刚度矩阵hydrostatic force水静压力linear damping force 线性阻尼力.thruster force推进器的力total reaction forcel/wave force低频力和波频力。

Unit Nine Text I A Red Light for Scofflaws Frank Trippettw-and-order is the longest-running and probably the best-loved political issue in U.S. history. Y et it is painfully apparent that millions of Americans who would never think of themselves as lawbreakers, let alone criminals, are taking increasing liberties with the legal codes that are designed to protect and nourish their society. Indeed, there are moments today—amid outlaw litter, tax cheating, illicit noise and motorized anarchy—when it seems as though the scofflaw represents the wave of the future. Harvard Sociologist David Riesman suspects that a majority of Americans have blithely taken to committing supposedly minor derelictions as a matter of course. Already, Riesman says, the ethic of U.S. society is in danger of becoming this: "Y ou're a fool if you obey the rules."2.Nothing could be more obvious than the evidence supporting Riesman. Scofflaws abound in amazing variety. The graffiti-prone turn public surfaces into visual rubbish. Bicyclists often ride as though two-wheeled vehicles are exempt from all traffic laws. Litterbugs convert their communities into trash dumps. Widespread flurries of ordinances have failed to clear public places of high-decibel portable radios, just as earlier laws failed to wipe out the beer-soaked hooliganism that plagues many parks. Tobacco addicts remain hopelessly blind to signs that say NO SMOKING. Respectably dressed pot smokers no longer bother to duck out of public sight to pass around a joint. The flagrant use of cocaine is a festering scandal in middle-and upper-class life. And then there are (hello, Everybody!) the jaywalkers.3.The dangers of scofflawry vary wildly. The person who illegally spits on the sidewalk remains disgusting, but clearly poses less risk to others than the company that illegally buries hazardous chemical waste in an unauthorized location. The fare beater on the subway presents less threat to life than the landlord who ignores fire safety statutes. The most immediately and measurably dangerous scofflawry, however, also happens to be the most visible. The culprit is the American driver, whose lawless activities today add up to a colossal public nuisance. The hazards range from routine double parking that jams city streets to the drunk driving that kills some 25,000 people and injures at least 650,000 others yearly. Illegal speeding on open highways? New surveys show that on some interstate highways 83% of all drivers are currently ignoring the federal 55 m.p.h. speed limit.4.The most flagrant scofflaw of them all is the red-light runner. The flouting of stop signals has got so bad in Boston that residents tell an anecdote about a cabby who insists that red lights are "just for decoration." The power of the stoplight to control traffic seems to be waning everywhere. In Los Angeles, red-light running has become perhaps the city's most common traffic violation. In New Y ork City, going through an intersection is like Russian roulette. Admits Police Commissioner Robert J. McGuire: "Today it's a 50-50 toss-up as to whether people will stop for a red light." Meanwhile, his own police largely ignore the lawbreaking.5.Red-light running has always been ranked as a minor wrong, and so it may be in individual instances. When the violation becomes habitual, widespread and incessant, however, a great deal more than a traffic management problem is involved. The flouting of basic rules of the road leaves deep dents in the social mood. Innocent drivers and pedestrians pay a repetitious price in frustration, inconvenience and outrage, not to mention a justified sense of mortal peril. The significance of red-light running is magnified by its high visibility. If hypocrisy is the tribute that vice pays to virtue, then furtiveness is the true outlaw's salute to the force of law-and-order. Thered-light runner, however, shows no respect whatever for the social rules, and society cannot help being harmed by any repetitious and brazen display of contempt for the fundamentals of order. 6.The scofflaw spirit is pervasive. It is not really surprising when schools find, as some do, that children frequently enter not knowing some of the basic rules of living together. For all their differences, today's scofflaws are of a piece as a symptom of elementary social demoralization—the loss by individuals of the capacity to govern their own behavior in the interest of others.7.The prospect of the collapse of public manners is not merely a matter of etiquette. Society's first concern will remain major crime (see Cover Story), but a foretaste of the seriousness of incivility is suggested by what has been happening in Houston. Drivers on Houston freeways have been showing an increasing tendency to replace the rules of the road with violent outbreaks. Items from the Houston police department's new statistical category—freeway traffic violence: 1) Driver flashes high-beam lights at car that cut in front of him, whose occupants then hurl a beer can at his windshield, kick out his tail lights, slug him eight stitches' worth. 2) Dump-truck driver annoyed by delay batters trunk of stalled car ahead and its driver with steel bolt. 3) Hurrying driver of 18-wheel truck deliberately rear-ends car whose driver was trying to stay within 55 m.p.h. limit. The Houston Freeway Syndrome has fortunately not spread everywhere. But the question is: Will it?8.Americans are used to thinking that law-and-order is threatened mainly by stereotypical violent crime. When the foundations of U.S. law have actually been shaken, however, it has always been because ordinary law-abiding citizens took to skirting the law. Major instance: Prohibition. Recalls Donald Barr Chidsey in On and Off the Wagon: "Lawbreaking proved to be not painful, not even uncomfortable, but, in a mild and perfectly safe way, exhilarating." People wiped out Prohibition at last not only because of the alcohol issue but because scofflawry was seriously undermining the authority and legitimacy of government. Ironically, today's scofflaw spirit, whatever its undetermined origins, is being encouraged unwittingly by government at many levels. The failure of police to enforce certain laws is only the surface of the problem; they take their mandate from the officials and constituents they serve. Worse, most state legislatures have helped subvert popular compliance with the federal 55 m.p.h. law, some of them by enacting puny fines that trivialize transgressions. On a higher level, the Administration in Washington has dramatized its wish to nullify civil rights laws simply by opposing instead of supporting certain court-ordered desegregation rulings. With considerable justification, environmental groups, in the words of Wilderness magazine, accuse the Administration of "destroying environmental laws by failing to enforce them, or by enforcing them in ways that deliberately encourage noncompliance." Translation: scofflawry at the top.9.The most disquieting thing about the scofflaw spirit is its extreme infectiousness. Only a terminally foolish society would sit still and allow it to spread indefinitely.From: M. A. Miller, pp. 266-269Unit Ten Text I Straight-A Illiteracy James P. Degnan1.Despite all the current fuss and bother about the extraordinary number of ordinary illiterates who overpopulate our schools, small attention has been given to another kind of illiterate, an illiterate whose plight is, in many ways, more important, because he is more influential. This illiterate may, as often as not, be a university president, but he is typically a Ph.D., a successful professor and textbook author. The person to whom I refer is the straight-A illiterate, and the following is written in an attempt to give him equal time with his widely publicized counterpart. Comment on the the effect of the present tense, the parallelism, and name of the student, and other linguistic devices used to highlight the problem of this straight-A illiterate.2.The scene is my office, and I am at work, doing what must be done if one is to assist in the cure of a disease that, over the years, I have come to call straight-A illiteracy. I am interrogating, I am cross-examining, I am prying and probing for the meaning of a student’s paper. The student is a college senior with a straight-A average, an extremely bright, highly articulate student who has just been awarded a coveted fellowship to one of the nation’s outstanding graduate schools. He and I have been at this, have been going over his paper sentence by sentence, word by word, for an hour. “The choice of exogenous variables in relation to multi-colinearity,” I hear myself reading from his pape r, “is contingent upon the derivations of certain multiple correlation coefficients.” I pause to catch my breath. “Now that statement, I address the student --- whom I shall call, allegorically, Mr. Bright —“that statement, Mr. Bright, what on earth does it mean?” Mr. Bright, his brow furrowed, tries mightily. Finally, with both of us combining our linguistic and imaginative re-sources, finally, after what seems another hour, we decode it. We decide exactly what it is that Mr. Bright is trying to say, what he really wants to say, which is: “Supply determines demand.”3.Over the past decade or so, I have known many students like him, many college seniors suffering from Bright’s disease. It attacks the best minds, and gradually destroys the critical faculties, making it impossible for the sufferer to detect gibberish in his own writing or in that of others. During the years of higher education it grows worse, reaching its terminal stage, typically, when its victim receives his Ph.D. Obviously, the victim of Br ight’s disease is no ordinary illiterate. He would never turn in a paper with misspellings or errors in punctuation; he would never use a double negative or the word “irregardless.” Nevertheless, he is illiterate, in the worst way: he is incapable of saying, in writing, simply and clearly, what he means. The ordinary illiterate --- perhaps providentially protected from college and graduate school --- might say: “Them people down at the shop better stock up on what our customers need, or we ain’t gonna be in business long.” Not our man. Taking his cue from years of higher education, years of reading the textbooks and professional journals that are the major sources of his affliction, he writes: “The focus of concentration must rest upon objectives centered around the knowledge of customer areas so that a sophisticated awareness of those areas can serve as an entrepreneurial filter to screen what is relevant from what is irrelevant to future commitments.” For writing such gibberish he is awarded straight As on his papers (both samples quoted above were taken from papers that received As), and the opportunity to move, inexorably, toward his fellowship and eventual Ph.D.4.As I have suggested the major cause of such illiteracy is the stuff --- the textbooks and professional journals --- the straight-A illiterate is forced to read during his years of higher education. He learns to write gibberish by reading it, and by being taught to admire it asprofundity. If he is majoring in sociology, he must grapple with such journals as the American Sociological Review, journals bulging with barbarous jargon, such as “ego-integrative action orientation”and “orientation toward improvement of the gratificational-deprivation balance of the actor” (the latter of which monstrous phr ases represents, to quote Malcolm Cowley, the sociologist’s way of saying “the pleasure principle”). In such journals, Mr. Cowley reminds us, two things are never described as being “alike.” They are “homologous” or “isomorphic. Nor are things simply “different.” They are “allotropic.” In such journals writers never “divide anything.” They “dichotomize” or “bifurcate” things.From: M. A. Miller, pp. 355-358Unit Eleven Text I On Consigning Manuscripts to Floppy Discs and Archives to OblivionWillis E. McNelly1.Manuscripts, those vital records of an author’s creative process, are an endangered species. The advent of word processors, and their relatively low cost together with increasing simplic ity, means that even impoverished, unpublished, would-be write rs’ (as well as the Names who top the best-seller list) have turned to their Wangs, IBMs and Apples, inserted Wordstar, Scriptsit or Apple Writer programs and busily begun writing, editing and revising their creative efforts. The result? A floppy disc!2.We should deplore the disappearance of manuscripts. How can anyone, student or scholar, learn anything about the creative process from a floppy disc? Can this wobbly plastic reveal the hours, the endless hours, where beauty was born out of its own despair (as William Butler Y eats put it) and blear-eyed wisdom out of midnight oil? Manuscripts are these records of creative agony, often sweat-stained, coffee-splattered or cigarette-charred. Manuscripts tell us what went on in a writer’s soul, how he or she fel t during the agony of creation. Edna St.V incent Millay may have burned the candle at both ends and wondered at its lovely light, but her first I drafts are treasures for future generations.3.Imagine if Yeats had written those magnificent lyrics celebrating his futile love for Maud Gonne on a word processor! No floppy disc can possibly reveal the depth of his sorrow. Almost a century later his manuscripts in the National Library in Dublin still glow with the power of his passion. They tell young, wan poets of either sex that faded tearstains are not new, that their feelings, hopes, despairs, loves and losses are actually eternal. Suppose Ray Bradbury had written “Fahrenheit 451” on a Wang. How appropriate, even ironic, it might have been had his various drafts gone the way of the burning books that he deplores and disappeared into a memory bank.4.Fortunately, any student of writing can inspect those same drafts in the Special Collections Library of California State University, Fullerton. Novices and professionals alike can examine how a brief story, “The Fireman,” grew into an unpublished novelette, “Fire Burn, Fire Burn!” and then developed into another longer version, “The Hearth and the Salamander,” also unpublished. The final copy (complete with an occasional typo, since it was typed by the author himself) is available for inspection. On these pages Bradbury’s own bold handwriting has substituted a vivid verb for a flabby one, switched a sentence or two around, sharpened or sometimes eliminated an adjective, substituted a better noun. The manuscript provides a perfect example of the artist at work. We would never see that kind of development or final polishing on any number of floppy discs.5.Moreover, put a lot of manuscripts together and you have an archive. Memoranda, diaries, journals, jottings, first, second and third drafts --- these archives are important to all of us. The archives of a city are often musty collections of scribbled scraps of paper, meaningful doodles about boundary lines or endless handwritten records of marriages, divorces, deeds, births and deaths. Our country’s archives of all kinds are a priceless heritage. The National Archives is jammed with ragged papers, preserved for the scrutiny of historians.6.Manuscripts tell us how Thomas Jef ferson’s mind worked as he drafted the Declaration of Independence. A famous letter to the president of Y ale informs us of Benjamin Franklin’s true feelings about religion. We’ve learned volumes from the diaries, papers, letters and exhortations of those who put our Constitution together. Would we know as much if they had done it all on a newfloppy disc? Unthinkable!7.Similarly, would letters from famous men and women spewed out on a dot-matrix printer have the same fascination as an original holograph? Would a machine-signed, mass-produced letter generated in some White House basement have the same emotional impact --- or the same value, for that matter --- as a handwritten letter mailed by Citizen Ronald Reagan in 1965, complete with hand-addressed envelope and canceled 5-cent stamp? Hardly.8.James Joyce once wrote that the errors of an artist are the portals of discovery. Unfortunately, we’ll never know of those errors if clean, neat, immaculate but errorless floppy discs replace tattered, pen-scratched, scissored, taped, yellowed, rewritten, retyped manuscripts. Libraries preserve them, students learn from them, auctioneers cry them at fabulous prices, owners cherish them. And word processors totally eliminate them. Our loss would be incalculable.9.Manuscripts are our gift to our heritage, and we have no right to deprive future generations of learning how we think and feel, simply because we find word processing more convenient. Patiently corrected manuscripts, not floppy discs, can tell any novice writer or future historian that writing is hard work, that it takes vision and revision alike --- and that it should be done on paper, not with electrons on a screen.From: J. R. McCuen and A. C. Winkler, pp. 512-515Unit Twelve Text I Grant and Lee: A Study in Contrasts Bruce Catton1.When Ulysses S. Grant and Robert E. Lee met in the parlor of a modest house at Appomattox Court House’, V irginia, on April 9, 1865, to work out the terms for the surrender of Lee’s Army of Northern V irginia, a great chapter in American life came to a close, and a great new chapter began.2.These men were bringing the Civil War to its virtual finish. To be sure, other armies had yet to surrender, and for a few days the fugitive Confederate government would struggle desperately and vainly, trying to find some way to go on living now that its chief support was gone. But in effect it was all Over when Grant and Lee signed the papers. And the little room where they wrote out the terms was the scene of one of the poignant, dramatic contrasts in American history.3.They were two strong men, these oddly different generals, and they represented the strengths, of two conflicting currents that, through them, had come into final collision.4.Back ofRobert E. Lee was the notion that the old aristocratic concept might somehow survive and be dominant in American life.5.Lee was tidewater V irginia, and in his background were family, culture, and tradition… the age of chivalry transplanted to a New World which was making its own legends and its own myths. He embodied a way of life that had come down through the age of knighthood and the English country squire. America was a land that was beginning all over again, dedicated to nothing much more complicated than the rather hazy belief that all men had equal rights and should have an equal chance in the world. In such a land Lee stood for the feeling that it was somehow of advantage to human society to have a pronounced inequality in the social structure. There should be a leisure class, backed by ownership of land; in turn, society itself should be keyed to the land as the chief source of wealth and influence. It would bring forth (according to this ideal) a class of men with a strong sense of obligation to the community; men who lived not to gain advantage for themselves, but to meet the solemn obligations which had been laid on them by the very fact that they were privileged. From them the country would get its leadership; to them it could look for the higher values --- of thought, of conduct, of personal deportment --- to give it strength and virtue.6.Lee embodied the noblest elements of this aristocratic ideal. Through him, the landed nobility justified itself. For four years, the Southern states had fought a desperate war to uphold the ideals for which Lee stood. In the end, it almost seemed as if the Confederacy fought for Lee; as if he himself was the Confederacy... the best thing that the way of life for which the Confederacy stood could ever have to offer. He had passed into legend before Appomattox. Thousands of tired, underfed, poorly clothed Confederate soldiers, long since past the simple enthusiasm of the early days of the struggle, somehow considered Lee the symbol of everything for which they had been willing to die. But they could not quite put this feeling into words. If the Lost Cause, sanctified by so much heroism and so many deaths, had a living justification, its justification was General Lee.7.Grant, the son of a tanner on the Western frontier, was everything Lee was not. He had come up the hard way and embodied nothing in particular except the eternal toughness and sinewy fiber of the men who grew up beyond the mountains. He was one of a body of men who owed reverence and obeisance to no one, who were self-reliant to a fault, who cared hardly anything for the past hut who had a sharp eye for the future.8.These frontier men were the precise opposites of the tidewater aristocrats. Back of them, in the great surge that had taken people over the Alleghenies and into the opening Western country, there was a deep, implic it dissatisfaction with a past that had settled into grooves. They stood fordemocracy, not from any reasoned conclusion about the proper ordering of human society, but simply because they had grown up in the middle of democracy and knew how it worked. Their society might have privileges, but they would be privileges each man had won for himself. Forms and patterns meant nothing. No man was born to anything, except perhaps to a chance to show how far he could rise. Life was competition.9.Y et along with this feeling had come a deep sense of belonging to a national community. The Westerner who developed a farm, opened a shop, or set up in business as a trader, could hope to prosper only as his own community prospered --- and his community ran from the Atlantic to the Pacific and from Canada down to Mexico. If the land was settled, with towns and highways and accessible markets, he could better himself. He saw his fate in terms of the nation’s own destiny. As its horizons expanded, so did his. He had, in other words, an acute dollars-and cents-stake in the continued growth and development of his country.10.And that, perhaps, is where the contrast between Grant and Lee becomes most striking. The Virginia aristocrat, inevitably, saw himself in relation to his own region. He lived in a static society which could endure almost anything except change. Instinctively, his first loyalty would go to the locality in which that society existed. He would fight to the limit of endurance to defend it, because in defending it he was defending everything that gave his own life its deepest meaning.11.The Westerner, on the other hand, would fight with an equal tenacity for the broader concept of society. He fought so because everything he lived by was tied to growth, expansion, and a constantly widening horizon. What he lived by would survive or fall with the nation itself. He could not possibly stand by unmoved in the face of an attempt to destroy the Union. He would combat it with everything he had, because he could only see it as an effort to cut the ground out from under his feet.12.So Grant and Lee were in complete contrast, representing two diametrically opposed elements in American life. Grant was the modern man emerging; beyond him, ready to come on the stage, was the great age of steel and machinery, of crowded cities and a restless burgeoning vitality. Lee might have ridden down from the old age of chivalry, lance in hand, silken banner fluttering over his head. Each man was the perfect champion of his cause, drawing both his strengths and his weaknesses from the people he led.13.Y et it was not all contrast, after all. Different as they were — in background, in personality, in underlying aspiration --- these two great soldiers had much in common. Under everything else, they were marvelous fighters. Furthermore, their fighting qualities were really very much alike. 14.Each man had, to begin with, the great virtue of utter tenacity and fidelity. Grant fought his way down the Mississippi V alley in spite of acute personal discouragement and profound military handicaps. Lee hung on in the trenches at Petersburg after hope itself had died. In each man there was an indomitable quality… the born fighter’s refusal to give up as long as he can still remain on his feet and lift his two fists.15.Daring and resourcefulness they had, too; the ability to think faster and move faster than the enemy. These were the qualities which gave Lee the dazzling campaigns of Second Manassas and Chancellorsville and won Vicksburg for Grant.stly, and perhaps greatest of all, there was the ability, at the end, to turn quickly from war to peace once the fighting was over. Out of the way these two men behaved at Appomattox came the possibility of a peace of reconciliation. It was a possibility not wholly realized, in the years to come, but which did, in the end, help the two sections to become one nation again…after a warwhose bitterness might have seemed to make such a reunion wholly impossible. No part of either man’s life became him more than t he part he played in this brief meeting in the McLean house at Appomattox. Their behavior there put all succeeding generations of Americans in their debt. Two great Americans, Grant and Lee --- very different, yet under everything very much alike. Their encounter at Appomattox was one of the great moments of American history.From: K. Flachmann and M. Flachmann, pp. 305-311。

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第一部分（共20小题，每小题1.5分，满分30分）1．She was so angry and spoke so fast that none of us understood ______ he said meant．A．that B．what C．that that D．what what2．The climate conference was attended by 11,000 people, it the largest UN gathering ever held.A．making B．to make C．made D．to be making3．He is confident, ________________ in my opinion, is most important in society.A．how B．whichC．that D．what4．______ caught in the rain unexpectedly, we still enjoyed the journey very much.A．When B．AsC．Unless D．Although5．—What it be?—It be a man, for it is not moving. It be a dustbin, I think.A．can; may; must B．can; can’t; mustC．can; must; can D．may; may not; could6．Mike is looking for another job because he feels that nothing he does his boss.A．serves B．satisfiesC．promises D．supports7．—________ the woman with the baby come over? We have a seat here.—Thank you, sir. Actually I do have my seat here. But my baby likes to look out of the window.A．Would B．ShallC．Must D．May8．The professor _____about how to protect the endangered animal in the conference at this time tomorrow. A．talked B．talks C．has been talking D．will be talking9．if I had arrived yesterday without letting you know beforehand?A．Would you be surprised B．Were you surprisedC．Had you been surprised D．Would you have been surprised10．The ordinary people all look at the intelligent man with admiration because under no circumstances ________ to cope with emergencies.A．he will fail B．is he failingC．he is failing D．will he fail11．After he consulted with his professor，an idea was beginning to____________ in his mind.A．pay off B．take shapeC．work out D．make up12．The project is far behind schedule. It’s impossible for you to ______ it in a week.A．catch upon B．live up toC．add up to D．hold on to13．If he ____hard, he would have passed the exam.A．were to work B．had workedC．should work D．was to work14．---Did you visit the famous cultural relics last month?---No, we____ it, but we spent too much time shopping．A．could have visited B．must have visitedC．can't have visited D．shouldn't have visited15．That children ______meet with setbacks is a matter of necessity as they_____, so parents don’t worry about that. A．shall; grew up B．must；grew up C．can; grow up D．will; grow up16．Y ou ________ have booked the tickets in advance; there were plenty left.A．needn’t B．can’tC．shouldn’t D．mustn’t17．In this movie going season, women are driving ticket sales to a degree ,if ever, seen before.A．really B．frequentlyC．rarely D．never18．—Shall we put off the experiment till next week?—______, I don’t think our teacher will be happy with it.A．Never mind B．Sure, go aheadC．Y es, better not D．I’d rather not19．－prlfessor, do you have something at this moment?－No,thanks.I'llcall you if there is any.A．typing B．typed C．to type D．to be typed20．More wild tigers have been seen in the forest around this area, ____ there used to be very few.A．when B．where C．what D．which第二部分阅读理解（满分40分）阅读下列短文，从每题所给的A、B、C、D四个选项中，选出最佳选项。

warm front 暖锋cold front 冷锋occluded front 锢囚锋point of occlusion 锢囚点cold occluded front 冷性锢囚锋warm occluded front 暖性锢囚锋neutral occluded front 中性锢囚锋rapidly moving cold front 快行冷锋slowly moving cold front 慢行冷锋anabatic front 上滑锋katabatic cold front 下滑锋principal front 主锋secondary front 副锋secondary cold front 副冷锋dry cold front 干冷锋stationary front 静止锋frontogenesis 锋生function of frontogenesis 锋生函数frontolysis 锋消orographic frontogenesis 地形锋生polar front 极锋arctic front 北极锋antarctic front 南极锋surface front 地面锋upper front 高空锋frontal analysis 锋面分析frontal weather 锋面天气warm front cloud system 暖锋云系cold front cloud system 冷锋云系frontal precipitation 锋面降水orographic occluded front 地形锢囚锋North China occluded front 华北锢囚锋orographic stationary front 地形静止锋South China quasi-stationary front 华南准静止锋Kunming quasi-stationary front 准静止锋Tianshan quasi-stationary front 天山准静止锋synoptic analysis 天气分析synoptic situation 天气形势synoptic process 天气过程synoptic system 天气系统planetary scale system 行星尺度系统synoptic scale system 天气尺度系统subsynoptic scale system 次天气尺度系统mesoscale system 中尺度系统microscale system 小尺度系统circulation pattern 环流型upper-level jet stream 高空急流low-level jet stream 低空急流boundary layer jet stream 边界层急流cold wave 寒潮cold outburst 寒潮爆发tropical meteorology 热带气象学intertropocal convergence zone, ITCZ 热带辐合带tropical easterlies jet 热带东风急流tropical high 热带高压tropical circulation 热带环流tropical monsoon 热带季风equatorial buffer zone 赤道缓冲带easterly wave 东风波subtropical easterlies 副热带东风带subtropical calms 副热带无风带subtropical westerlies 副热带西风带tropical cyclone 热带气旋tropical disturbance 热带扰动tropical depression 热带低压tropical storm 热带风暴typhoon 台风binary typhoons 双台风typhoon eye 台风眼storm center 风暴中心storm surge 风暴潮storm of Bay of Bengal 孟加拉湾风暴Meiyu, plum rain 梅雨Meiyu front 梅雨锋onset of Meiyu 入梅ending of Meiyu 出梅Meiyu period 梅雨期returning flow weather 回流天气downburst 下击暴流El Nino 厄尔尼诺ENSO 恩索La Nina 拉尼娜southern oscillation, SO 南方涛动quasi-biennial oscillation, QBO 准两年振荡equatorial low 赤道低压equatorial easterlies 赤道东风带equatorial westerlies 赤道西风带equatorial calms 赤道无风带polar meteorology 极地气象学polar vortex 极涡circumpolar westerlies 绕极西风带arctic anticyclone 北极反气旋polar low 极地低压polar anticyclone 极地反气旋weather forecast 天气预报severe weather warning 危险天气警报urban weather 城市天气severe tropical storm 强热带风暴single station [weather] forecast 单站[天气]预报supplementary [weather] forecast 补充[天气]预报nowcast 临近预报foehn effect 焚风效应heat wave 热浪plateau meteorology 高原气象学Qinghai-Xizang high 青藏高压mountain meteorology 山地气象学very short-range [weather] forecast 甚短期[天气]预报short-range [weather] forecast 短期[天气]预报medium-range [weather] forecast 中期[天气]预报long-range [weather] forecast 长期[天气]预报extra long-range [weather] forecast 超长期[天气]预报extended forecast 延伸预报persistence forecast 持续性预报seasonal forecast 季节预报statistical forecast 统计预报objective forecast 客观预报perfect prediction 完全预报subjective forecast 经历预报regional forecast 区域预报forecast amendment 订正预报local forecast 局地预报predictability 可预报性deterministic prediction 确定性预报forecast accuracy 预报准确率operational forecast 业务预报predictor 预报因子predictand 预报量weather outlook 天气展望synoptic code 天气电码forecast score 预报评分forecast verification 预报检验local weather 地方性天气natural synoptic period 自然天气周期natural synoptic season 自然天气季节natural synoptic region 自然天气区07. 气候学climatology 气候学marine climatology 海洋气候学aviation climatology 航空气候学aeroclimatology 高空气候学tropical climatology 热带气候学synoptic climatology 天气气候学statistical climatology 统计气候学climatological statistics 气候统计学satellite climatology 卫星气候学physical climatology 物理气候学dynamic climatology 动力气候学mountain climatology 山地气候学topoclimatology 地形气候学macroclimatology 大气候学microclimatology 小气候学applied climatology 应用气候学environment climatology 环境气候学paleoclimatology 古气候学climate 气候climatic element 气候要素factors for climatic formation 气候形成因子climatological observation 气候观测climatic monitoring 气候监测solar climate 太阳气候ideal climate 理想气候global climate 全球气候global climate system 全球气候系统macroclimate 大气候mesoclimate 中气候microclimate 小气候regional climate 区域气候local climate 局地气候topoclimate 地形气候urban climate 城市气候indoor climate 室气候paleoclimate 古气候continental climate 大陆性气候marine climate 海洋性气候arid climate 干旱气候semi-arid climate 半干旱气候humid climate 湿润气候warm-wet climate 湿热气候coastal climate 滨海气候nival climate 冰雪气候glacioclimate 冰川气候antarctic climate 南极气候arctic climate 北极气候mountain climate 山地气候plateau climate 高原气候vertical climatic zone 垂直气候带forest climate 森林气候diurnal variation 日变化departure 距平diurnal range 日较差annual range 年较差annual mean 年平均annual amount 年总量season 季节seasonality 季节性transition season 过渡季节frost peroid 霜期frost day 霜日rainy season 雨季hot season 热季cool season 凉季continentality 大陆度oceanity 海洋度air-sea interaction 海气相互作用water cycle 水循环drought frequency 干旱频数drought index 干旱指数dry season 干季dry spell 干期aridity 枯燥度moisture index 湿润度greenhouse effect 温室效应heat island effect 热岛效应heat sink 热汇heat source 热源heat balance 热量平衡climatography 气候志periodogram 周期图climatic map 气候图climatic atlas 气候图集pentad 候wind rose 风玫瑰图wind vector 风矢量average wind velocity 平均风速resultant wind 合成风firn 永久积雪firn line 永久雪线isoneph 等云量线isochion 等雪量线isohel 等日照线climatological front 气候锋planetary wind system 行星风系trade winds 信风anti-trade 反信风temperate westerlies 温带西风带monsoon 季风summer monsoon 夏季风winter monsoon 冬季风East Asian monsoon东亚季风plateau monsoon 高原季风monsoon burst 季风爆发monsoon onset 季风建立monsoon depression 季风低压monsoon circulation 季风环流monsoon climate 季风气候monsoon region 季风区monsoon index 季风指数break monsoon 季风中断climatic type 气候型climatic classification 气候分类climate regionalization 气候区划climatic region 气候区climatic belt, climaic zone 气候带polar climate 极地气候subarctic climate 副极地气候temperate climate 温带气候subtropical climate 副热带气候tropical climate 热带气候equatorial climate 赤道气候K?ppen's climate classification 柯本气候分类tropical climate A热带气候类tropical rainy climate 热带常湿气候亚类tropical winter dry climate 热带冬干气候亚类tropical monsoon rain climate 热带季风雨气候亚类arid climate 枯燥气候类steppe climate 草原气候亚类desert climate 沙漠气候亚类winter moderate climate 冬温气候类winter moderate and winter dry climate 冬温冬干气候亚类winter moderate and summer dry climate 冬温夏干气候亚类winter moderate and rainy climate 冬温常湿气候亚类winter cold climate 冬寒气候类winter cold and rainy climate 冬寒常湿气候亚类winter cold and winter dry climate 冬寒冬干气候亚类polar climate 极地气候类tundra climate 苔原气候亚类perpetual frost climate 永冻气候亚类Thornthwaite's climatic classification 桑思韦特气候分类climatic analysis 气候分析climatic data 气候资料climatic statistics 气候统计climatic persistence 气候持续性climatic non-periodic variation 气候非周期变化climatic periodic variation 气候周期性变化climatic sensitivity气候敏感性climate resources 气候资源climatic probability 气候概率climatic variability 气候变率interannual variability 年际变率climatological standard normals 气候标准平均值energy balance model 能量平衡模式statistical-dynamic model 统计动力模式nuclear winter 核冬天climatic variation 气候变迁climatic change 气候变化climatic oscillation 气候振荡climatic fluctuation 气候振动climatic revolution 气候演变climatic reconstruction 气候重建climate periodicity 气候周期性climatic simulation 气候模拟climate sensitivity experiment 气候敏感性实验climatic diagnosis 气候诊断teleconnection 遥相关probability forecast 概率预报abrupt change of climate 气候突变climatic deterioration 气候恶化desertization, desertification 荒漠化climatic trend 气候趋势climatic adaptation, acclimatization 气候适应climatic impact 气候影响climatic domestication 气候驯化climatic anomaly 气候异常climatic prediction 气候预测climate noise 气候噪声climate damage 气候灾害climatic feedback mechanism 气候反应机制numerical climatic classification 数值气候分类climatic assessment 气候评价dendroclimatology 树木年轮气候学dendroclimatography 树木年轮气候志historical climate 历史气候ice age 冰期little ice age 小冰期interglacial period 间冰期post-glacial climate 冰后期气候Quaternary climate 第四纪气候climate modification 人工影响气候artificial microclimate 人工小气候phytotron 人工气候室phenological division 物候分区phenological observation 物候观测phenodate 物候日phenospectrum 物候谱phenogram 物候图isophene 等物候线duration of frost-free period 无霜期08. 应用气象学applied meteorology 应用气象学agricultural meteorology, agrometeorology 农业气象学evapotranspiration 蒸散transpiration 蒸腾potential evapotranspiration 潜在蒸散soil water balance 土壤水分平衡soil water content 土壤含水量effective precipitation 有效降水critical period of [crop] water requirement [作物]需水临界期precipitation inversion 降水逆减saturation moisture capacity 饱和持水量[absolute] soil moisture 土壤[绝对]湿度relative soil moisture 土壤相对湿度field capacity 田间持水量wilting moisture 凋萎湿度soil evaporation 土壤蒸发soil water potential 土壤水势crop water requirement 作物需水量surface temperature 地面温度ground temperature 地温soil temperature 土壤温度active temperature 活动温度effective temperature 有效温度optimum temperature 最适温度accumulated temperature 积温active accumulated temperature 活动积温effective accumulated temperature 有效积温agricultural threshold temperature 农业界限温度leaf temperature 叶温frozen soil 冻土maximum depth of frozen ground 最大冻土深度photoperiodism 光周期[性]thermoperiodism 温周期[性]photosynthetically active radiation, PAR 光合有效辐射illumination length 光照长度critical day-length 临界光长photophase 光照阶段light resources 光资源heat resources 热量资源agrometeorological observation 农业气象观测agrometeorological model 农业气象模式twenty-four solar terms 二十四节气agrometeorological hazard 农业气象灾害dry hot wind 干热风late spring cold 倒春寒low temperature damage in autumn 寒露风dark frost 黑霜freezing injury 冻害frost injury 霜冻wet damage 湿害hot damage 热害cool damage 冷害wind damage 风害chilling injury 寒害snow damage 雪灾hail damage 雹灾drought damage 旱灾drought 干旱agrometeorological forecast 农业气象预报agrometeorological information 农业气象情报agrometeorological index 农业气象指标agricultural climatology, agroclimatiology 农业气候学agroclimatic evaluation 农业气候评价agroclimatic analysis 农业气候分析agroclimatic atlas 农业气候图集agroclimatic demarcation, agroclimatic division 农业气候区划agroclimatic resources 农业气候资源climatic risk analysis 气候风险分析agroclimatic analogy 农业气候相似agroclimatic potential productivity [农业]气候生产潜力agroclimatic index 农业气候指标agroclimatic classification 农业气候分类meteorological proverb 气候谚语agroclimatography 农业气候志phenology 物候学phenophase 物候期phytoclimatology 植物气候学agricultural microclimate 农业小气候microclimate in the fields 农田小气候biometeorology 生物气象学biological zero point 生物学零度animal husbandry meteorology 畜牧气象学soil climate 土壤气候phytoclimate 植物[小]气候marginal effect 边际效应vegetation index 植被指数meteorology of crops 作物气象ecoclimatology 生态气候学bioclimatology 生物气候学aeronautical meteorology 航空气象学aviation meteorological observation 航空气象观测aviation area [weather] forecast 航空区域[天气]预报aviation meteorological information 航空气象情报aeronautical climate regionalization 航空气候区划airplane meteorological sounding 飞机气象探测significant meteorological information 重要气象情报hazardous weather message 危险天气通报aerodrome hazardous weather warning 机场危险天气警报meteorogram 天气实况演变图aviation meteorological element 航空气象要素ICAO standard atmosphere 国际民航组织标准大气flight visibility 空中能见度runway visual range 跑道能见度icing on runway 跑道积冰meteorological minimum 最低气象条件aerodrome meteorological minimum 机场最低气象条件unflyable weather 禁飞天气plain-language report 明语气象报告aviation meteorological code 航空气象电码pilot meteorological report 飞行员气象报告aviation meteorological support 航空气象保障appointed airdrome weather report 机场预约天气报告aircraft weather reconnaissance 飞机天气侦察VOLMET broadcast 对空气象播送aviation [weather] forecast 航空[天气]预报air route [weather] forecast 航线[天气]预报amendment of aviation weather forecast 航空天气订正预报landing [weather] forecast 着陆[天气]预报aerodrome special weather report 机场特殊天气报告altimeter setting 高度表拨定[值]aircraft icing 飞机积冰clear air turbulence, CAT 晴空湍流aircraft bumpiness 飞机颠簸aircraft trail 飞机尾迹[exhaust]contrail [废气]凝结尾迹[exhaust] evaporation trail [废气]蒸发尾迹aircraft wake 飞机尾流low-level wind shear 低空风切变airdrome pressure 场面气压tail wind 顺风cross wind 侧风head wind 逆风navigation wind航行风wind sleeve 风向袋aeronautical climatography 航空气候志military meteorology 军事气象学military meteorological support 军事气象保障military climatography 军事气候志military meteorological information 军事气象情报ballistic wind 弹道风ballistic temperature 弹道温度ballistic air density弹道空气密度medical meteorology 医疗气象学biometeorological index 生物气象指数sensible temperature 感觉温度wind-chill index 风寒指数comfort index 舒适指数discomfort index 不适指数comfort current 舒适气流comfort temperature 舒适温度industrial climate 工业气候degree-day 度日heating degree-day采暖度日cooling degree-day 冷却度日water resources 水资源building climate 建筑气候wind induced oscillation 风振climate stress load 气候应力荷载snow load 雪荷载wind stress 风应力wind load 风荷载building climate demarcation 建筑气候区划predominant wind direction 主导风向prevailing wind 盛行风wind velocity fluctuation 风速脉动wind pressure 风压maximum wind pressure 最大风压coefficient of wind pressure 风压系数windage effect 风阻影响steady wind pressure 稳定风压maximum instantaneous wind speed 最大瞬时风速maximum design wind speed 最大设计平均风速breaking wind speed 破坏风速snow pressure 雪压energy source meteorology 能源气象学wind energy 风能wind energy resources 风能资源effective wind speed 有效风速available wind energy 有效风能wind energy rose 风能玫瑰[图]wind energy potential 风能潜力wind energy demarcation 风能区划wind energy content 风能资源储量wind energy density 风能密度wind site assessment 风场评价wind farm 风力田solar energy resources 太阳能资源solar energy demarcation 太阳能区划pollution meteorology 污染气象学atmospheric background 大气本底[值]atmospheric pollution 大气污染air pollution 空气污染sampling interval 采样间隔atmospheric quality standard 大气品位标准atmospheric pollution sources 大气污染源primary pollutant 原生污染物secondary pollutant 次生污染物atmospheric cleaning 大气净化atmospheric diffusion equation 大气扩散方程[environment] atmospheric quality monitoring [环境]大气质量监测air pollution modeling 空气污染模拟air pollution model 空气污染模式air pollutant emission 空气污染物排放loading of air pollutant 空气污染物含量air pollutant emission standard 空气污染物排放标准floating dust 飘尘dustfall 降尘greenhouse gasses 温室气体atmospheric pollutant 大气污染物smog aerosol 烟雾气溶胶ash cloud 烟灰云smog 烟雾smoke screen 烟幕blood-snow 血雪blood-rain 血雨acid rain 酸雨precipitation acidity 降水酸度plume type 烟羽类型plume rise 烟羽抬升plume height 烟羽高度buoyant plume 浮升烟羽stratospheric pollution 平流层污染fallout 沉降物fallout wind 沉降风urban air pollution 城市空气污染smoke烟smoke plume 烟羽atmospheric pollution monitoring 大气污染监测assessment of atmospheric environment 大气环境评价atmospheric environment capacity 大气环境容量forest meteorology 森林气象学forest limit temperature 森林界限温度maximum shelter distance 最大防护距离wind break 风障forest-fire [weather] forecast 林火[天气]预报weather grade of forest 森林火险天气等级forest microclimate 森林小气候hydrometeorology 水文气象学flood period 汛期high flow year 丰水年low flow year 枯水年normal flow year 平水年water budget 水分收支probable maximum flood 可能最大洪水hydrometeorological forecast 水文气象预报design torrential rain 设计暴雨precipitable water 可降水量probable maximum precipitation, PMP 可能最大降水area mean rainfall 区域平均雨量marine meteorology 海洋气象学marine weather forecast 海洋天气预报marine meteorological code 海洋气象电码sea surface radiation 海面辐射sea surface temperature, SST 海面温度sea surface albedo 海面反照率brave west wind 咆哮西风带arctic [sea] smoke 北冰洋[烟]雾gale warning 大风警报meteorological shipping route 气象航线optimum route 最正确航线meteorological navigation 气象导航。

Large Scale Parameters and Double-Directional Characterization of Indoor Wideband Radio Multipath Channels at11GHz Minseok Kim,Member,IEEE,Yohei Konishi,Student Member,IEEE,Yuyuan Chang,andJun-ichi Takada,Senior Member,IEEEAbstract—This paper presents the large scale parameters of wideband multipath channels based on extensive measurement campaigns in various indoor environments.The measurements were conducted with a wideband multiple-input multiple-output (MIMO)channel sounder having a bandwidth of400MHz at11 GHz which is a challenging frequency for future mobile systems. In particular,polarization characteristics of path-loss,shadowing, cross-polarization power ratio(XPR),delay spread and coher-ence bandwidth are characterized.The measurement results show that the path-loss exponents range between2.0and3.0 for none-line-of-sight(NLoS),0.36and1.5for LoS,respectively. Vertically and horizontally polarized transmissions have almost same path-gain,but in some corridor-room NLoS environments, the path-loss for HH is significantly large.In most cases,the RMS delay spreads are less than20and50ns for NLoS and LoS,respectively,and the average coherence bandwidth is less than30MHz.The Rician-factors range between2and3dB for cross-polarization,and in large Hall environments,those for co-polarization are greater than6.0dB with10%probability. Finally,some dominant propagation mechanism and site-specific behaviors are illustrated using the double-directional measure-ment results.Index Terms—Delay spread,indoor,path-loss,radio propaga-tion,shadowing,wideband,11GHz.I.I NTRODUCTIONA S the data traffic in mobile Internet services has been dra-matically increasing because of the explosion in usage of smartphones and tablet devices,conventional cellular networks covering large cell area cannot be expected to provide sufficient capacity and satisfactory data rates.In recent3G cellular sys-tems universally available portable services have been realized, and data rates of approximately several tens of megabits per second can be experienced in the current LTE/LTE-A systems. However,tremendous data traffic will still be a major concern for future mobile systems.Because of the technical challenges in increasing the capacity and data rates to a much greater de-gree,there has been an increasing interest in deploying relays,Manuscript received July30,2013;revised September24,2013;accepted October25,2013.Date of publication November05,2013;date of current ver-sion December31,2013.This work was supported in part by the Research and Development Project for Expansion of Radio Spectrum Resources of The Min-istry of Internal Affairs and Communications,Japan.The authors are with the Graduate School of Science and Engineering,Tokyo Institute of Technology,Tokyo,Japan(e-mail:mskim@).Color versions of one or more of thefigures in this paper are available online at .Digital Object Identifier10.1109/TAP.2013.2288633distributed antenna systems,and small cell communications in densely populated areas[1],[2].In addition,further increase in frequency bandwidth will be necessary.However,because of the serious congestion of the frequency spectrum at lower microwave bands(below5GHz), exploring new frequency bands above5GHz is an inevitable choice in the future.These higher frequency bands were previ-ously neglected by land mobile researchers because of their high path-loss with distance[3],[5].Further,deep shadowing due to weak diffraction and higher Doppler frequency are expected. Thus,using high frequency bands has been considered disad-vantageous in mobile transmission.However,the radio propa-gation properties at higher frequency bands have not been suf-ficiently justified from the view point of the requirements for current mobile data transmission.In fact,a large path-loss is not always a disadvantage,and can be an advantage when de-signing small cell or hot spot systems within a confined cov-erage area where very high-speed data transmission can be re-alized because a very wide frequency bandwidth is available. Thus,extensive measurement based characterization of the radio propagation properties at higher frequency bands is neces-sary to determine the operation strategy and to design the system parameters.In small cell environments,the channel behaviors should be quite site-specific depending on the individual en-vironments,so that the design and analysis of the system re-quire more sophisticated channel models of correlation among the multiple links in relay,distributed antennas,and other coop-erative schemes,and a possible rank of the multiple-input mul-tiple-output(MIMO)channels.This work presents the radio channel characteristics over wide bandwidth of400MHz with the carrier frequency of11 GHz which has been chosen assuming a mobile system with an area smaller than the conventional microcell coverage area[1], [2].Although a large number of studies have been conducted on the radio channel for mobile systems below5GHz,to our best knowledge,only few measurements and analyses at around11GHz have been found[4]–[8].In1989,some basic propagation experiments were conducted on the path-loss characteristics in microcell environments having a low base station antenna height at11GHz[4].In[5],a measurement at 10GHz was conducted and a statistical model of small-scale fading in some indoor environments was presented.In[6],[7], Janssen et al.conducted extensive measurements in an indoor office environment at2.4,4.75,and11.5GHz,and provided some insights on channel characteristics such as path-loss,0018-926X©2013IEEEroot-mean-square(RMS)delay spread,and coherence band-width from the comparative analyses of the three frequencies.A large path-loss in obstructed line-of-sight(OBS)situations and small delay spread(515ns)observed at11.5GHz over the other two frequencies.Additionally,a comparative study on the coherence bandwidth at11.2and62.4GHz for indoor line-of-sight(LoS)microcells has been presented in[8]. Because the polarization characteristics of the radio channel are important for polarization diversity with co-located an-tennas,the polarization effects in an indoor environment at various frequency bands have been discussed,[9]–[17].Orthog-onally polarized MIMO systems use low correlation between two polarizations,so the orthogonally polarized antennas can be co-located to enable the design of a compact antenna system. Because the two orthogonal polarization components of an electromagnetic wave are independent,the correlation between antennas for different polarizations will also be low with low coupling with each other.Comparing with existing studies mentioned above,the orig-inal contribution of this paper is to present the polarization behaviors of the large scale parameters at a new challenging frequency band of11GHz.Specifically,this paper presents them based on extensive measurement campaigns in various in-door environments of the university building in Tokyo Institute of Technology,Japan.The measurements have been conducted with a wideband MIMO channel sounder having a bandwidth of400MHz at11GHz[19].The instantaneous channel transfer functions were taken using dual-polarized dipole antennas on both sides of the transmitter and the receiver.This paper presents the most fundamental parameters,which describe the dominant characteristics of the environment,including path-loss,shadowing,and RMS delay spread,and coherence bandwidth in terms of the polarization.In addition,the mea-sured narrowband Rician-factors will also be discussed to describe the contribution of thefixed coherent component in the measurement environments.Finally,the dominant propa-gation mechanism and site-specific behavior of the individual environment will be illustrated using the double-directional measurement results.The remainder of this paper is organized as follows.The measurement campaign including the MIMO channel sounder and measurement environments are described in Section II. Section III presents the large scale parameters;path-loss, shadowing,cross polarization power ratio(XPR)/co-polariza-tion power ratio(CPR),RMS delay spread,and coherence bandwidth.Next,the narrowband Rician-factors of each environment are presented in Section IV.Then,the dominant propagation mechanism with double-directional measurement results are discussed in Section V.Finally,conclusions and a summary of the results are given in Section VI.II.M EASUREMENT C AMPAIGNA.MIMO Channel SounderFor the measurements,dual-polarized,namely,vertically polarized(VP)and horizontally polarized(HP),dipole an-tennas having an omni-directional azimuth radiation pattern with a gain of4dBi were used.The half beam width inTABLE IC HANNEL S OUNDING PARAMETERSthe vertical pattern was35degrees.The triple-link124 dual-polarized MIMO channel measurement was configured with a12-element(6VP/HP)linear array at the transmitter and4-element(2VP/HP)antenna array at the three receivers, respectively.Table I shows the measurement parameters in detail.The antenna spacing of the array was approximately, and the transmitting power per antenna was10dBm.In the channel sounder,the channel transfer functions(TFs)of2,048 sub-carriers over400MHz bandwidth were measured in a single snapshot by transmitting an unmodulated multitone signal[19].The noisefloor in the path gain measurement was approximately91dB with respect to the level(0dB)in the back-to-back direct connection between the transmitter and the receiver.By inverse discrete Fourier transform(IDFT)of the TFs,the impulse response(IR)of the-th snapshot for the-th transmit antenna to the-th receive antenna is obtained as(1) where and denote discrete frequency and delay indices, respectively.Here,is a window function that reduces the side lobe effect in estimating the IR and the correction factor.denotes the transfer function of the -th the-th transmit antenna to the-th receive an-tenna.It should be noted that the sum power of IR in the delay domain is equal to the mean power of TF in the frequency do-main from Parseval’s theorem as(2) The noise level in IR is approximately124dB with a matched filter gain of33dB.The maximum measurable excess delay is4.Fig.1.MIMO channel sounder configurations.(a)MIMO channel measure-ment.(b)Double-directional channel measurement.The MIMO channel sounder has a fully parallel transceiver architecture that employs a layered scheme of frequency divi-sion multiplexing(FDM)and space-time division multiplexing (STDM).Fig.1shows the photographs of the channel sounder where the number of antennas is scalable by a combination of multiple transceiver units,and there isflexibility for both the multi-link(ML)MIMO channel measurement shown in Fig.1(a)and the double-directional channel measurement shown in Fig.1(b)[19],[20].The frequency and time synchro-nizations between the units were precisely taken with a cesium atomic clock(accuracy:).In fact,the measurement of all the MIMO sub-channels of the three links were taken si-multaneously.However,in this paper,multiple MIMO channel responses were used to characterize the large-scale parameters through spatial averaging.B.Measurement EnvironmentsIn the following scenarios,the specified number of snapshots were obtained by moving the transmitter slowly along the routes at a constant speed(0.25m/s).At the speed the Doppler phase shift is negligibly small.The surrounding environment was maintained to be static during a measurement.In each environment,the ML channel measurement was conducted by synchronizing two or three different receiver units and simultaneously measuring all the MIMO sub-channels of those links.The dimensions and conditions of the environments in NLoS and LoS scenarios are presented in Table II.1)NLoS Scenarios(Corridor-Room):For NLoS scenarios, the measurement campaign was carried out at thefirst level of the lecture building.It mainly consists of a30-m-long corridor, some lecture rooms,a meeting room,and some laboratories.The walls between the rooms were constructed with plasterboards, but those between the corridor and the rooms were constructed with reinforced concrete.Thefloor was made of reinforced con-crete.Thefloor plan is depicted in Fig.2(a).220snapshots wereTABLE IIM EASUREMENT E NVIRONMENTSobtained at every14cm(about)by moving the transmitter along the corridor(Route1).Two receivers with a dual-polar-ized4-element antenna array(2V/H)were located at two dif-ferent points of RxA and RxB in Room A and Room B,respec-tively.Further,the area of Room B was twice that of Room A, and the metallic doors of Room A and B were opened,but those of others were closed.As can be expected from thefloor plan in Fig.2(a),all the measurement points are in NLoS for Room A,but they can be divided into the following three parts for Room B as:•NLoS(Area1):the transmitter was located in the corridor and there was no LoS path.•LoS:the receiver could see the transmitter through the open door.•NLoS(Area2):there were a rest room and an entrance area in the vicinity of the transmitter.Because of the differences in the surrounding environments,the NLoS channels for Area1and2were separately characterized.2)LoS Scenarios:The measurement was also conducted in three different LoS environments,as shown in Fig.2(b)and(c), where Room C,Hall D and Hall E denote a medium scale lecture room having a metal platefloor,an entrance hall,and a large event hall,respectively.In Room C,two metallic white boards are installed on the front and rear side walls,and a part of the wall is also made of metal,as shown in Fig.2(b).Similar to the NLoS measurements,220,440,and390snap-shots were taken by moving the transmitter along the routes in the scenarios of Room C(Route2and3),Hall D(Route4and 5)and Hall E(Route6and7),respectively.During the mea-surement of Hall D and Hall E,in some instances,there were people passing by or resting in chairs.III.C HARACTERIZATION OF L ARGE S CALE P ARAMETERSA.Path-Loss and ShadowingThe polarimetric path gain was calculated by averaging the local path gains(PGs)of all the MIMO channels over the entire bandwidth as(3) where and can take either horizontal(‘H’)or vertical(‘V’) polarizations,and and denote the sets of the transmit and the receive antenna indices for the and polarizations,respec-tively.Further,denotes the maximum delay index of the power level greater than the noise level.For all the cases,256 delay samples from the zero delay were used,Fig.2.Floor plan views of the measurement environments (Tx moved slowly along the routes at constant speed)where ‘’s on the routes denote the Tx positions for further analysis in the subsequent sections.(a)NLoS (Room A and Room B);(b)LoS (Room C and Hall D);(c)LoS (HallE).Fig.3.Measured PL and PL models of indoor NLoS measurement (Corridor-Room).(a)Co-polarization.(b)Cross-polarization.which is equivalent to 640ns in the continuous delay domain.In addition to averaging over spatial and frequency domains in (3),averaging a few snapshots further eliminated a small scale fading effect,and then,the path-loss for each polarization pair was calculated from the reciprocal of the path gain.It should be noted that the total antenna gain of 8dBi at both the transmit and receive sides was excluded from the path-loss.The measured path-losses of the NLoS and LoS conditions for each polarization pair are shown in Figs.3and 4,respec-tively,where the path gains were averaged within approximately 0.5m .For each case,the path-loss was characterized using the measurement data.The measured path-losses were lin-early fitted into the widely accepted power-law model by plot-ting the path-loss (PL)in terms of the distance between the transmitter and the receiver on the log-log scale as(4)where and denote the path-loss exponent and the intercept at 1m distance,respectively.Here,indicates a log-normally distributed random variable with zero mean and variance .The fitted models are plotted in Figs.3and 4where the free space path-lossis shown with a dashed line for reference,and the model parameters are summarized in Table III.The propagation mechanism for the NLoS channel between the corridor and Room A involves the propagation of the trans-mitted waves along the corridor with a number of sidewall re-flections that then flow into the room.The waves are also accu-mulated after re flection from the metallic door at the end of the corridor as shown in Fig.2(a).In Room B,similar to Room A the waves propagate by the waveguide effect of the corridor and then flow into the room in the corridor Area 1.The path-loss ex-ponents of the co-polarization for Room A and Room B (Area 1)ranged between 2.0and 2.6.However,in Room B (Area 2),a signi ficant amount of transmission power leaks to the rest room and the entrance area.Hence,the power drops faster with dis-tance (and 6.2for VV and HH,respectively).The path-losses for both the cross-polarization pairs (VH and HV)decrease with distance in similar ways,as shown in Fig.3(b).It should be noted that the path-losses for the horizontally polarized (HP)transmitter-receiver pairs (HH)are larger than those for the vertically polarized (VP)ones (VV)in the case of co-polarization (particularly in Room B),as shown in Fig.3(a).Fig.4.Measured PL and PL models of indoor LoS measurement.(a)Co-polarization.(b)Cross-polarization.TABLE IIIP ATH -L OSS M ODEL PARAMETERSAs discussed in [10],[11],this is mainly because of the different re flection coef ficients for different polarizations.The horizon-tally polarized waves undergo a Brewster angle phenomenon,so only penetration can occur through the walls leading to the larger path-losses for HH over VV.Moreover,trends similar to the results of [12]at 2.6GHz were found.On the other hand,as shown in Fig.4,the path-loss exponents in the LoS environments range between 0.55and 1.5for co-po-larization and between 0.36and 1.0for cross-polarization.We see that the LoS path-loss has an exponent less than 2,which in-dicates a guiding effect of the environments.Further,the larger the area of the environment,the faster is the power fall-off with distance.Notably,co-polarization was observed to decay faster than cross-polarization,which is in contrast with the results of [11],[12].As shown in Table III,we can see that the shadowing values measured in each scenario are small (less than 2dB).We per-formed the Kolmogorov-Smirnov goodness-of-fit test (KS test)that is a widely accepted method to compare a sample with a reference probability distribution [18].It should be noted that in all NLoS cases the null hypothesis that shadowing follows log-normal distribution were accepted at the signi ficance level,although it was not always true in LoS cases. B.Cross Polarization Power Ratio (XPR)An important parameter that characterizes the channel polar-ization is the cross-polarization power ratio (XPR)de fined as(5)(6)which indicates the power ratios of co-polarization to cross-po-larization.It should be noted that the XPD (cross polarization discrimination),de fined in [14],is a polarization property of the antenna element,whereas the XPR indicates the polarization be-havior of the propagation channel.Similarly,the co-polarization power ratio (CPR)is de fined as(7)which indicates the power ratio of the vertical polarization (VV)to the horizontal polarization (HH).Figs.5and 6show the measured XPR and CPR in the NLoS and LoS environments,respectively.The measured XPRs and CPRs in the NLoS corridor-room environment are randomly distributed,and signi ficant dependency on the distance between the transmitter and the receiver was not found,as shown in Fig.5(a)and (b),respectively.Further,Fig.5(c)shows the cu-mulative distribution function (CDF)of the agglomerated data of XPRs and CPRs,where the mean XPRs are found to be 12.8dB and 11.6dB ,respectively.From the mea-sured CPRs,we can see that the horizontally polarized wave is rotated through the channel;thus,the power leaks to the vertical polarization.Further,large CPRs could be found in Room B in-dicating that the path-loss of HH is signi ficantly larger than that of VV because of the vertical sidewall re flections as explained above.For LoS environments,both of the XPR and CPR seem to depend on distance as shown in Fig.6(a)and (b),respectively.The Spearman’s rank correlation coef ficient provides a non-parametric measure of the statistical dependency between two variables [26].In this case,we used distance and XPR/CPR as the two variables.Further,we attempted statistical tests usingFig.5.Measured XPR and CPR in NLoS environments (corridor-room),and the statistical models.(a)XPR.(b)CPR.(c)CDFs of XPR andCPR.Fig.6.Measured XPR and CPR in LoS environments,and the models by linear fitting.(a)XPR.(b)CPR.(c)CDFs of and .the values under the null hypothesis,i.e.,no correlation be-tween these two variables.The calculated p-values using the Spearman’s rank test were (XPR,Room C),(XPR,Room D),0(XPR,Room E),(CPR,Room C),0.19(CPR,Room D),and 0.31(CPR,Room E).From these results,we can see that the XPRs are strongly correlated to the distance because the p-values were smaller than the sig-ni ficance level of 0.05,but for CPR only Room C showed some correlation.Similarly,for the path-loss model,they can be rep-resented by a linear model on a log-log scale as(8)(9)where and denote an exponent and intercept at 1m,respec-tively.and indicate the log-normally distributed random variables with zero mean and variance and ,respectively.From the measured XPRs,we can see that the bigger the area of the environment,the larger is the XPR,i.e.,.Consequently,the cross-couplingterm in (5)and (6)will be reduced,and the LoS and specular re-flection components can become much more dominant in a large open space.As the overview of the existing measurement results was pre-sented in [15],from the indoor measurement at 1.8GHz in [17],the average XPR and CPR were 7dB and 0dB,respec-tively.In an of fice environment at 2.4GHz,the average XPR was reported as 15dB [11].In another measurement at 2.4GHz[9],the average XPRs for LoS and NLoS were 16and 8dB,respectively.In [16],the XPRs at 5.2GHz are distributed 715.7dB and 8.614.4dB ,respectively.On the other hand,in the measurement at 11GHz,the mea-sured XPRs and CPRs for NLoS were distributed 520and,respectively,and those for LoS were approxi-mately distributed 1020dB and ,respectively.From these results,we can see that the XPR values at higher frequency are relatively larger because of large scattering loss in cross-polar transmissions.C.Temporal Dispersion and RMS Delay SpreadTemporal dispersion is also a crucial parameter that needs to be characterized when designing a wireless data transmission scheme.The maximum data rate without inter-symbol interfer-ence (ISI)depends on the spread in the delay domain which also indicates the fading correlation in the frequency domain under the wide sense stationary (WSS)and uncorrelated scat-tering (US)assumptions [21].The power-delay pro file (PDP)for the -th snapshot can be obtained as(10)A typical PDP for each polarization pair in each environment is shown in Fig.7.Although the gains and shapes of VH and HV are not very different,we can see that the gain of HH degradedFig.7.Typical power delay profile(PDP)at each environment.(a)Room A;(b)Room B(Area1);(c)Room B(Area2);(d)Room C;(e)Hall D;(f)Hall E. noticeably when compared with that of VV in the NLoS envi-ronment.Further,much larger delay spreads were observed in the LoS environments than in the NLoS environments.Partic-ularly,in Room C a number of strong specular reflection com-ponents from the white boards in the front and rear sidewalls and some parts of the wall constructed with metal plates are ob-served until600ns as shown in Fig.7(d).The RMS delay spread is a commonly used parameter to rep-resent the temporal dispersion of the channel.It is calculated from the PDP and obtained from the power of the impulse re-sponse averaged over a local area having a dimensions of sev-eral wavelengths[22],[24].Using the PDP calculated by(10), the RMS delay spread is obtained by(11) where.Here,the indices of the snapshot and polar-ization of the PDP are omitted for simplicity,and(12) which denotes the mean delay[25].In this calculation,the threshold for the noise exclusion was set to be20dB from the peak of the PDP[23].Here,the data taken at the transmitter positions where the difference between the peak and the noise level is greater than23dB for all polarization pairs were only used(20%in NLoS and99%in LoS).Figs.8(a)and9(a) show the CDFs of the RMS delay spread.In most cases,the RMS delay spreads were less than20and50ns for NLoS and LoS environments,respectively,and those for the LoS environment were much widely distributed depending on the power of the LoS path.In addition,the RMS delay spread of cross-polarization was larger than that of co-polarization, which is attributed to the absence of dominant specular multi-path components in the channel of cross-polarization.Further, the power delay exponents in the delay profiles,those for the power of the co-and cross-polarizations are different with the co-polarization decaying slightly faster,which is particularly observed in the LoS environments as shown in Fig.7(e)and(f). This is also consistent with the results of path-loss shown in Fig.4(a)and(b)where co-polarization decays faster with distance than cross-polarization.D.Coherence BandwidthUnder the WSS and US assumptions,the normalized fre-quency correlation function(FCF)can be calculated as(13) where,and for. Once the correlation function is obtained,the coherence band-width can be determined in terms of a certain correlation level.At each transmitter position along the routes,the coher-ence bandwidth for the correlation level of was cal-culated.Figs.8(b)and9(b)show the CDFs of the coherence bandwidth for the NLoS and LoS environments,respectively, where the trend is in contrast with the RMS delay spread.For LoS environments,high frequency-coherence could be found because of the existence of the LoS path.To be more specific, with90%,the coherence bandwidth was less than36,60,and 19MHz,for Room A(NLoS),Room B(NLoS),and Room C (LoS with strong multipaths),respectively.With10%proba-bility,it was greater than84and200MHz for Hall D and E (LoS),respectively.The Fourier transform relation between PDP and FCF,the RMS delay spread,and coherence bandwidth can be inversely related as[27].From a theoretical analysis of the exponentially decaying PDPs,the uncertainty relationship that provides the relation of the confinement boundaryhas been derived[28].In[29],the rela-tionship has been characterized by linearfitting to the general-ized model of.Figs.8(c)and9(c)shows the relationship between the RMS delay spread and the coherence bandwidth measured by using the vertical polarization for the NLoS and LoS environments, respectively,where the solid line denotes the confinement boundary[28]for reference.As shown in Fig.8(c),for the NLoS,most of the points are located in the vicinity of Fleury’s confinement boundary in[28].However,for LoS environ-ments,they are widely distributed in the confinement domain of as shown in Fig.9(c).No-tably,because Room C is a multipath-rich environment,the points were located in a manner similar to those of the NLoS environments.Fig.8.Statistical distributions of RMS delay spread and coherence bandwidth for NLoS environments (Corridor-Room A/Room B).(a)CDFs of RMS delay spreads.(b)CDFs of coherence bandwidth.(c)Scatter plot of RMS delay spread and coherencebandwidth.Fig.9.Statistical distributions of RMS delay spread and coherence bandwidth for LoS environments (Room C/Hall D/Hall E).(a)CDFs of RMS delay spreads.(b)CDFs of coherence bandwidth.(c)Scatter plot of RMS delay spread and coherencebandwidth.Fig.10.Empirical CDFs of the measured narrowband factors.(a)Room C.(b)Hall D.(c)Hall E.IV .N ARROWBAND R ICIAN -F ACTORThe key parameter of the fading distribution is the Rician -Factor,which is the power ratio of the fixed and scattered components [30],[31].It is a measure of the richness of multi-path and the severity of narrowband fading.In the LoS environ-ment,the received signal envelope is usually modeled by Rician distribution as(14)where and are the shape and scale parameters,respectively,and is the 0-th order modi fied Bessel function of the first kind.Parameter (called the Rician -factor)indi-cates the ratio of the power of the fixed coherent component to the power contribution of the non-coherent scattered paths.In order to characterize the multipath richness of the environ-ments,the Rician -factor for each LoS environment was cal-culated as shown in Fig.10.Most existing studies have followed the moment-based method proposed in [30],[31],whereas the Rician parameters in (14)have been directly calculated by dis-tribution fitting with the amplitudes of 256narrowband sub-channels of the measured snapshot for the robustness of the cal-culation.From Fig.10,it is observed that for cross-polarization,the -factors ranged between 2and 3because the power of the。

ORIGINAL PAPERLong-term time-dependent stochastic modelling of extreme wavesErik VanemPublished online:5August 2010ÓThe Author(s)2010.This article is published with open access at Abstract This paper presents a literature survey on time-dependent statistical modelling of extreme waves and sea states.The focus is twofold:on statistical modelling of extreme waves and space-and time-dependent statistical modelling.The first part will consist of a literature review of statistical modelling of extreme waves and wave parame-ters,most notably on the modelling of extreme significant wave height.The second part will focus on statistical modelling of time-and space-dependent variables in a more general sense,and will focus on the methodology and models used also in other relevant application areas.It was found that limited effort has been put on developing statis-tical models for waves incorporating spatial and long-term temporal variability and it is suggested that model improvements could be achieved by adopting approaches from other application areas.In particular,Bayesian hier-archical space–time models were identified as promising tools for spatio-temporal modelling of extreme waves.Finally,a review of projections of future extreme wave climate is presented.Keywords Extreme waves ÁStochastic modelling ÁSpatiotemporal modelling ÁClimate change ÁRisk assessment1IntroductionAccording to casualty statistics,one of the major causes of ship losses is bad weather (Guedes Soares et al.2001),which stresses the importance of taking extreme sea state conditions adequately into account in ship design.There-fore,a correct and thorough understanding of meteoro-logical and oceanographic conditions,most notably the extreme values of relevant wave and wind parameters,is of paramount importance to maritime safety.Thus,there is a need for appropriate statistical models to describe these phenomena.When designing ships and other marine and offshore structures,relevant safety regulations and design standards should be based on the best available knowledge.Meteo-rological data for the last 50?years are available and this is often assumed to be representative also for the current sit-uation.However,ships and other marine structures are designed for lifetimes of several decades and design codes and standards should be based on knowledge about the operating environment throughout the expected lifetime of the structure—several decades into the future.Such knowledge will also be crucial for any risk assessment of maritime transportation or offshore operations.According to the IPCC Fourth Assessment Report (IPCC 2007),the globe is currently experiencing climate change and the Earth is warming.It is also very likely that human activities and emission of greenhouse gasses are mainly responsible for the recent rise of global tempera-tures.Projections of future climate indicate that it is very likely that frequencies and intensities of extreme weather events will increase (IPCC 2007).Model projections also show a poleward shift of the storm tracks with more extreme wave heights in those regions.Thus,it is increasingly evident that climate change is a reality.An overwhelming majority of researchers and sci-entists agree on this and it is reasonable to assume that the averages and extremes of sea states are changing and cannot be considered stationary.Hence,it is no longerE.Vanem (&)Statistics Division,Department of Mathematics,University of Oslo,P.O.Box 1053,Blindern,0316Oslo,Norway e-mail:erikvan@math.uio.noStoch Environ Res Risk Assess (2011)25:185–209DOI 10.1007/s00477-010-0431-ysufficient to base design codes on stationary wave param-eters without any consideration of how these are expected to change in the future.There is a need for time-dependent statistical models that can take the time-dependency of the integrated wave parameters into account,and also ade-quately model the uncertainties involved,in order to pre-dict realistic operating environments throughout the lifetime of ships and marine structures.This paper aims at providing a comprehensive,up-to-date review of statistical models proposed for modelling long-term variability in extreme waves and sea states as well as a review of alternative approaches from other areas of application.The paper is organized as follows:Section2 outlines alternative sources of wave data,Sect.3comprises a review of statistical models for extreme waves,Sect.4 presents a review of relevant spatio-temporal statistical models from other areas of application,Sect.5reviews projections of future wave climate and Sect.6concludes with some recommendations for further research.An abbreviated version of this work was presented at the OMAE conference this year(Vanem2010).Efforts have been made to include all relevant and important work to make this literature survey as complete as possible,and this has resulted in a rather voluminous list of references at the end of the paper.Notwithstanding,due to the enormous amount of literature in thisfield some important works might inevitably have been omitted.This is unintended and it should be noted that important con-tributions to the discussion herein might exist of which I have not been aware.Nevertheless,it is believed that this literature study contains a fair review of relevant literature and as such that it gives a good indication of state-of-the art within thefield and may serve as a basis for further research on stochastic modelling of extreme waves and sea states.1.1Integrated sea state parametersThe state of the sea changes constantly,and it is therefore neither very practical nor very useful to describe the sea for an instantaneous point in time.Therefore,sea states are normally described by different averages and extreme values for a certain period of time,often referred to as integrated sea state parameters.Typically,such integrated parameters include the significant wave height,1mean wave period,mean main wave direction,spread of the wave direction and mean swell.Such integrated wave parameters represent averages over a defined period of time,typically in the order of20–30min.Integrated wave parameters,which are averages over different periods of time,will have its own averages and extremes.Of particular interest may be the m-year return value of the significant wave height,SWH m,which is defined as the value of H S that is exceeded on average once every m years.In ship design,the SWH20has traditionally been of particular interest since ships are normally designed for a lifetime of20years.The modelling of such extreme values,for example for the significant wave height,is therefore of interest.It is also of interest to investigate how such average wave parameters vary over time.In particular,long term variations(i.e.how these parameters will vary in the next 50–100years)will be an important basis for design of marine and offshore structures with expected lifetimes in the range of several decades and also for maritime risk analyses.This is of particular importance at times where climate change indicates that the future is not well repre-sented by today’s situation(i.e.where an increase in extreme weather and sea state is expected).1.2Waves as stochastic processesAlthough the dynamics of the sea and the mechanisms underlying the generation of waves on the sea surface inevitably follows the laws of physics and therefore,in principle,the sea state could be described deterministically, in reality this is not possible due to the complexity of the system.Hence,the description of waves and the sea must be done probabilistically.The sea is a dynamic system that is influenced by innumerable factors and an infinite number of interrelated parameters would be needed in order to provide an exact description of the sea in any given point in time.It is simply not possible to know all and every one of these parameters.The unknown parameters introduce uncertainties to any description of the system and an exact description of the sea is therefore not feasible.Thus,the problem of describing the sea turns into a statistical prob-lem,and probabilistic models are needed in order to rep-resent waves on the sea surface and to provide a better understanding of the maritime environment in which ships operate.In this regard stochastic models would seem to be the most appropriate approach to describe extreme waves. Also,the fact that the sea state is normally described through different average and extreme properties,as dis-cussed briefly above,indicates that statistical tools are appropriate to model waves and sea states.A comprehen-sive overview of statistical techniques,methodologies, theories and tools used in climatic analyses is presented in von Storch and Zwiers(1999).Stochastic modelling of ocean waves can be performed on two very different time scales.In the short-term models, the parameters of most concern are those for individual1Significant waveheight,denoted SWH,HSor H1/3is often defined as the average wave height,from trough to crest,of the one-third largest waves that is observed during the period.waves such as individual wave height,wave length and period,etc.The times involved in such models are nor-mally in the order from a few seconds to a couple of hours. The long-term models mainly refer to the description of spectral parameters,and the times that are involved nor-mally span over many years.It is the latter time scales that are of main interest in the present work,considering modelling of possible long-term trends due to climate change.1.3Predicting the impact of climate change on extremesea statesThe state of the oceans and the characteristics of the waves are influenced by innumerable external factors,and the most influential boundary conditions are related to the atmosphere and the global and local climate in general. Atmospheric pressure,wind,temperature,precipitation, solar radiation and heat,tidal movements,the rotation of the earth and movements of the seabed(e.g.from earth-quakes or volcanic activities)are examples of external factors that jointly influence the generation of waves on the sea surface.In one sense,some of the average and extreme properties of the sea state can be regarded as stationary if the overall average boundary conditions does not change. That is,in spite of the continuous variations of sea states over time,the averages such as seasonal average wave heights and return periods for extreme waves can be con-sidered as stationary if the average boundary conditions (e.g.average atmospheric pressure,average wind,average temperatures,etc.)remain stationary.However,in recent years it has become increasingly apparent that the climate system overall is not stationary and that the climate will change in the near future—in fact it has been observed that the climate is already undergoing a change with a global long-term trend towards higher temperatures and more frequent and intense severe weather events,although local and regional trends may differ from this global trend.These climate changes—man-made or not—will thus change the overall boundary conditions for the sea,and the assumption that the average sea states can be regarded as stationary ceases to be valid.In order to predict future trends in sea state parameters in the non-stationary case,one may therefore start with predicting the trends in the boundary conditions such as temperature,atmospheric pressure and wind.Assuming that a significant part of the climate change is man-made and can be ascribed to the increasing emission of green-house gases,most notably CO2,and aerosols,predictions of climate change can be made based on various emission scenarios or forcing scenarios(Nakic´enovic´et al.2000). These forcing scenarios can then be fed into climate models to predict global trends in meteorological variables,which can again be used to predict trends in average and extreme properties of sea waves.However,most wave models are deterministic and not able to handle the inherent uncertainties involved in a rigorous manner.Estimates of future H S return values are difficult since there are no projections of future H Sfields.However, projections of sea level pressure provided by climate models are reasonable reliable and it is known that the H S fields are highly correlated with sea level pressurefields. Therefore,one approach could be to model H Sfields by regressing on projected sea level pressurefields,as was done in Wang et al.(2004).Other covariates may also be used to predict changes in extreme wave climate from projected changes in the overall climate,and the utilization of such dependencies may prove important in modelling long-term trends in extreme waves.2Wave data and data sourcesAs in all statistical modelling,a crucial prerequisite for any sensible modelling and reliable analysis is the availability of statistical data.For example,if models describing the spatio-temporal variability of extreme waves are to be developed,wave data with sufficient spatio-temporal res-olution is needed.Furthermore,the lack of adequate cov-erage in the data will restrict the scope of the statistical models that can be used.Wave data can be obtained from buoys,laser measure-ments,satellite images,shipborne wave recorders or be generated by numerical wave models.Of these,buoy measurements are most reliable,but the spatial coverage is limited.For regions where buoy data are not available, satellite data may be an alternative for estimation of wave heights(Krogstad and Barstow1999;Panchang et al. 1999),and there are different satellites that collect such data.Examples of satellite missions are the European Remote Sensing Satellites(ERS-1and ERS-2),the Topex/ Poseidon mission and Jason-1and-2missions.Wave parameters derived from satellite altimeter data were demonstrated to be in reasonable agreement with buoy measurements by the end of last century(Hwang et al.1998).More recently,further validation of wave heights measured from altimeters have been performed, and the agreement with buoy data is generally good (Queffeulou2004;Durrant et al.2009).However,correc-tions due to biases may be required,and both negative and positive biases for the significant wave height have been reported,indicating that corrections are region-dependent (Meath et al.2008).Sea state parameters such as signifi-cant wave height derived from synthetic aperture radar images taken from satellites were addressed in Lehner et al.(2007).Ship observations are another source of wave data which covers areas where buoy wave measurements are not available.The Voluntary Observing Ship(VOS)scheme has been in operation for almost150years and has a large set of voluntary collected data.However,due to the fact that ships tend to avoid extreme weather whenever possi-ble,extreme wave events are likely to be under-represented in ship observations and hence such data are not ideally suited to model extreme wave events(DelBalzo et al. 2003;Olsen et al.2006).Recently,a novel wave acquisition stereo system (WASS)based on a variational image sensor and video observational technology in order to reconstruct the4D dynamics of ocean waves was developed(Fedele et al. 2009).The spatial and temporal data provided by this system would be rich in statistical content compared to buoy data,but the availability of such data are still limited.In general,measurements of wave parameters are more scarce than meteorological data such as wind and pressure fields which are collected more systematically and cover-ing a wider area.An alternative is therefore to use output from wave models that uses meteorological data as input rather than to use wave data that are measured directly.Wave models are normally used for forecast or hindcast of sea states(Guedes Soares et al.2002).Forecasts typically predicts sea states up to3–5days ahead.Hindcast modelling can be used to calibrate the models after precise meteoro-logical measurements have been collected.It can also be used as a basis for design but it is stressed that quality control is necessary and possible errors and biases should be iden-tified and corrected(Bitner-Gregersen and de Valk2008).Currently,data are available from various reanalysis projects(Caires et al.2004).For example,40year of meteorological data are available from the NCEP/NCAR reanalysis project(Kalnay et al.1996)that could be used to run wave models(Swail and Cox2000;Cox and Swail 2001).A more recent reanalysis project,ERA-40(Uppala et al.2005),was carried out by the European Centre for Medium-Range Weather Forecasts(ECMWF)and covers a 45-year period from1957to2002.The data contain six-hourlyfields of global wave parameters such as significant wave height,mean wave direction and mean wave period as well as mean sea level pressure and windfields and other meteorological parameters.A large part of this reanalysis data are freely available for download from their website for research purposes.2It has been reported that the ERA-40dataset contains some inhomogeneities in time and that it underestimates high wave heights(Sterl and Caires2005),but corrected datasets for the significant wave height have been produced (Caires and Sterl2005).Hence,a new45-year global six-hourly dataset of significant wave height has been created, and the corrected data shows clear improvements com-pared to the original data.In Caires and Swail(2004)it is stated that this dataset can be obtained freely from the authors for scientific purposes.3Review of statistical models for extreme wavesIn order to model long-term trends in the intensity and frequency of occurrence of extreme wave events or extreme sea states due to climate change,appropriate models must be used.There are numerous stochastic wave models proposed in the literature,but most of these are developed for other purposes than predicting such long-term trends.Models used for wave forcasting,for example in operational simulation of safety of ships and offshore structures typically have a short-term perspective,and cannot be used to investigate long-term trends.Also,many wave models assume stationary or cyclic time series,which would not be the case if climate change is a reality.There are different approaches to estimating the extreme wave heights at a certain location based on available wave data,and some of the most widely used are the initial dis-tribution method,the annual maxima method,the peak-over-threshold method and the MEan Number of Up-crossings (MENU)method.The initial distribution method uses data (measured or calculated)of all wave heights and the extreme wave height of a certain return period is estimated as the quantile h p of the wave height distribution F(h)with proba-bility p.The annual maxima approach uses only the annual (or block)maxima and the extreme wave height will have one of the three limit distributions referred to as the family of the generalized extreme value distribution.The peak-over-threshold approach uses data with wave heights greater than a certain threshold,and thus allows for increased number of samples compared to the annual maxima approach.Waves exceeding this threshold would then be modelled according to the Generalized Pareto distribution.However,the peaks-over-threshold method has demonstrated a clear dependence on the threshold and is therefore not very reliable.The MENU method determines the return period of an extreme wave of a certain wave height by requiring that the expected or mean number of up-crossings of this wave height will be one for that time interval.Another approach useful in extreme event modelling is the use of quantile functions,an alternative way of defining a probability distribution(Gilchrist2000).The quantile function,Q,is a function of the cumulative probability of a distribution and is simply the inverse of the cumulative density function:Q(p)=F-1(p)and F(x)=Q-1(x).This function can then be used in frequency analysis tofind2Data available from url:http://data-portal.ecmwf.int/data/d/era40_ daily/.useful estimates of the quantiles of relevant return periods T of extreme events in the upper tail of the frequency distribution,Q T=Q(1-1/T).Yet another approach for estimating the maxima of a sta-tionary process is to model the number of extreme events, defined as the number of times the process crosses afixed level u in the upward direction,as a Poisson process(a counting process{N(t),t C0}with N(0)=0,independent increments and with number of events in a time interval of length t Poisson distributed with mean k t is said to be a Poisson process with rate k)and apply the Rice formula to compute the intensity of the extreme events(see e.g.Rychlik2000).In the following,a brief review of some wave models proposed in the literature will be given.This includes a brief description of some short-term and stationary wave models as well as a more comprehensive review of pro-posed approaches to modelling long term trends due to global climatic changes.An introduction to stochastic analysis of ocean waves can be found in Ochi(1998)and Trulsen(2006),albeit the latter with a particular emphasis on freak or rogue waves.3.1Short-term stochastic wave modelsWaves are generated from wind actions and wave predic-tions are often based on knowledge of the generating wind and wind-wave relationships.Most wave models for operational wave forecasting is based on the energy bal-ance equation;there is a general consensus that this describes the fundamental principle for wave predictions, and significant progress have been made in recent decades (Janssen2008).Currently,the third-generation wave model WAM is one of the most widely used models for wave forecasting(The WAMDI Group1988;Komen et al.1994) computing the wave spectrum from physicalfirst princi-ples.Other widely used wave models are Wave Watch and SWAN,and there exist a number of other models as well (The Wise Group et al.2007).However,wave generation is basically an uncertain and random process which makes it difficult to model deterministically,and in Deo et al. (2001),Bazargan et al.(2007)approaches using neural networks were proposed as an alternative to deterministic wave forecasting models.There are a number of short-term,statistical wave models for modelling of individual waves and for pre-dicting and forecasting sea states in the not too distant future.Most of the models for individual waves are based on Gaussian approaches,but other types of stochastic wave models have also been proposed to account for observed asymmetries(e.g.adding random correction terms to a Gaussian model(Machado and Rychlik2003)or based on Lagrangian models(Lindgren2006;Aberg and Lindgren 2008)).Asymptotic models for the distribution of maxima for Gaussian processes for a certain period of time exist, and under certain assumptions,the maximum values are asymptotically distributed according to the Gumbel distri-bution.However,as noted in Ryde´n(2006),care should be taken when using this approximation for the modelling of maxima of wave crests.A similar concern was expressed in Coles et al.(2003),albeit not related to waves.Given the short-term perspective of these types of models,they cannot be used to describe long-term trends due to climate change,nor to formulate design criteria for ships and offshore structures,even though they are important for maritime safety during operation.Improved weather and wave forecasts will of course improve safety at sea,but the main interest in the present study is on long-term trends in ocean wave climate,and the effect this will have on maritime safety and on the design of marine structures.Therefore,short-term wave models will not be considered further herein.3.1.1Significant wave height as a functionof wind speedThe significant wave height for a fully developed sea, sometimes referred to as the equilibrium sea approxima-tion,given afixed wind speed have been modelled as a function of the wind speed in different ways,for example as H S/U5=2or H S/U2(Kinsman1965).This makes it possible to make short-term predictions of the significant wave height under the assumptions of a constant wind speed and assuming unlimited fetch and duration.For developing sea conditions,with limited fetch or limited wind duration,the significant wave height as a function of wind speed,U(m/s)and respectively fetch X(km)and duration D(h)has been modelled in different ways,for example as H S*X1/2U and H S/D5=7U9=7(O¨zger and S¸en2007).However,it is observed that the equilibrium wind sea approximation is seldom valid,and an alternative model for predicting the significant wave height for wind waves, H S from the wind speed U10at a reference height of10m were proposed in Andreas and Wang(2007),using a dif-ferent,yet simple parametrization.18years of hourly data of significant wave height and winds speed for12different buoys were used in order to estimate the model which can be written on the following form:H S¼CðDÞIðU104m=sÞþaðDÞU210þbðDÞÂÃIðU10[4m=sÞð1ÞD denotes the water depth and C,a and b are depth-dependent parameters.Based on comparison with mea-surements it was concluded that this model is reliable for wind speeds up to at least U10=25m/s.It is out of scope of the present literature survey to review all models for predicting wave heights from wind speed or other meteorological data.Such models are an integral part of the various wave models available for wave forecasting, but cannot be used directly to model long-term variations in wave height.However,given adequate long-term wind forecasts,such relationships between wind speed and wave height may be exploited in simulating long-term wave data for long-term predictions of wave climate.3.2Stationary modelsA thorough survey of stochastic models for wind and sea state time series is presented in Monbet et al.(2007).Only time series at the scale of the sea state have been considered without modelling events at the scale of individual waves, and only at given geographical points.One section of Monbet et al.(2007)is discussing how to model non-sta-tionarity such as trends in time series and seasonal compo-nents,but for the main part of the paper it is assumed that the studied processes are stationary.The models have been classified in three groups:Models based on Gaussian approximations,other non-parametric models and other parametric models.In the following,the main characteristics for these different types of wave models are highlighted.Even though ocean wave time series cannot normally be assumed to be Gaussian,it may be possible to transform these time series into time series with Gaussian marginal distri-butions when they have a continuous state space(Monbet et al.2007).The transformed time series can then be simu-lated by using existing techniques to simulate Gaussian processes.If{Y t}is a stationary process in R d,assume that there exists a transformation f:R d?R d and a stationary Gaussian process{X t}so that Y t=f(X t).Such a procedure consists of determining the transformation function f,gen-eration of realizations of the process{X t}and then trans-forming the generated samples of{X t}into samples of{Y t} using f.A number of such models for the significant wave height have been proposed in the literature(e.g.Cunha and Guedes Soares(1999),Walton and Borgman(1990)for the univariate time series for significant wave height,H s,Guedes Soares and Cunha(2000),Monbet and Prevosto(2001)for the bivariate time series for significant wave height and mean wave period,(H s,T)and DelBalzo et al.(2003)for the multivariate time series for significant wave height,mean wave period and mean wave direction,(H s,T,H m)).How-ever,it is noted that the duration statistics of transformed Gaussian processes has been demonstrated not tofit too well with data,even though the occurrence probability is cor-rectly modelled(Jenkins2002).Multimodal wave models for combined seas(e.g.with wind-sea and swell components)have also been discussed in the literature(see e.g.Torsethaugen1993;Torsethaugen and Haver2004;Ewans et al.2006),but these are gener-ally not required to describe severe sea states where extremes occur(Bitner-Gregersen and Toffoli2009).A few non-parametric methods for simulating wave parameters have been proposed,as reported in Monbet et al. (2007).One may for example assume that the observed time series are Markov chains and use non-parametric methods such as nearest-neighbor resampling to estimate transition kernels.In Caires and Sterl(2005),a non-parametric regression method was proposed to correct outputs of meteorological models.A continuous space,discrete time Markov model for the trivariate time-series of wind speed, significant wave height and spectral peak period was pre-sented in Monbet and Marteau(2001).However,one major drawback of non-parametric methods is the lack of descriptive power.An approach based on copulas for multivariate model-ling of oceanographic variables,accounting for depen-dencies between the variables,were proposed in de Waal and van Gelder(2005)and applied to the joint bivariate description of extreme wave heights and wave periods.Parametric models for wave time series include various linear autoregressive models,nonlinear retrogressive mod-els,finite state space Markov chain models and circular time series models.A modified Weibull model was proposed in Muraleedharan et al.(2007)for modelling of significant and maximum wave height.For short-term modelling of wave parameters,different approaches of artificial neural net-works(see e.g.Deo et al.2001;Mandal and Prabaharan 2006;Arena and Puca2004;Makarynskyy et al.2005)and data mining techniques(Mahjoobi and Etemad-Shahidi 2008;Mahjoobi and Mosabbeb2009)have successfully been applied.A non-linear threshold autoregressive model for the significant waveheight was proposed in Scotto and Guedes Soares(2000).3.3Non-stationary modelsMany statistical models for extreme waves assume the sta-tionarity of extreme values,but there are some non-station-ary models proposed in the literature.In the following,some non-stationary models for extreme waves that are known and previously presented in the literature will be reviewed.A review of classical methods for asymptotic extreme value analysis used in extreme wave predictions are presented in Soukissian and Kalantzi(2006).3.3.1Microscopic modelsA number of statistical models have been presented in the literature where the focus has been to use sophisticated sta-tistical methods to estimate extreme values at certain specific geographical points(e.g.based on data measurements at that。

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1.立项依据与研究内容（4000-8000字）1.1项目的立项依据（研究意义、国内外研究现状及发展动态分析，需结合科学研究发展趋势来论述科学意义；或结合国民经济和社会发展中迫切需要解决的关键科技问题来论述其应用前景。

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至今为止，极值波高计算方法并未统一，包含诸多不确定因素，计算结果相差悬殊。

本课题拟系统分析和定量确定极值波高计算方法的各种不确定因素，研发新理论/方法将不确定因素影响最小化。

建立误差小、应用方便、统一化的极值波高计算模式。

具有工程应用价值。

本课题拟计算中国沿海极值波高的空间分布，该成果在海岸和海洋工程、深水港口和石油平台、沿海核电站等的工程设计、造价、结构安全、工程效益、环境影响等方面意义重大。

尤其对中国正在推行的“一带一路”国家级顶层战略，项目成果将为中国沿海港口的科学选址和工程设计提供高质量的极值波浪数据，具有重要的工程应用价值。

具有领先性。

本课题拟研究内容也是当今波浪推算研究领域的热点和难点，研究成果将会进一步提高中国学者在该研究领域的学术影响力和先进性。

1.1.2 国内外研究现状及发展动态分析当今国际学者们普遍接受的极值波高计算方法有三种：1）年N个大波法(ANL，Annual n-Largest method),是由经典的年大波法(n=1)延伸而来的（Sobeyn )，组和Orloff，1996）。

该方法从实测波浪数据中每年提出n个独立的大波(1成一个极值波浪数组，然后应用GEV极值函数来估算极值波高；2）阈值法（POT, Peaks-Over-Threshold method）（Hosking等，1987），该方法是设置一个阈值波高H o，将每个高于H o的波峰值从时间序列波浪数据中提出出来，组成一个极值波浪数组，然后应用GPD极值函数来计算极值波高；3）风暴波浪法（SAS, Storm-by-Storm Method）(Goda,1988)。