下载文档原格式
(一)投稿前准备工作和需要注意的事项、投稿过程相关经验总结投稿前准备工作和需要注意的事项：总结提示语：1)第一作者和通信作者的区别：通信作者(Corresponding author)通常是实际统筹处理投稿和承担答复审稿意见等工作的主导者，也常是稿件所涉及研究工作的负责人。
通信作者的姓名多位列于论文作者名单的最后(使用符号来标识说明是Corresponding author)，但其贡献不亚于论文的第一作者。
通讯作者往往指课题的总负责人，负责与编辑部的一切通信联系和接受读者的咨询等。
文章的成果是属于通讯作者的，说明思路是通讯作者的，而不是第一作者。
第一作者仅代表是你做的，且是最主要的参与者!通信作者标注名称：Corresponding author，To whom correspondence should be addressed,或The person to whom inquiries regarding the paper should be addressed若两个以上的作者在地位上是相同的，可以采取“共同第一作者”(joint first author)的署名方式，并说明These authors contributed equally to the work。
2)作者地址的标署：尽可能地给出详细通讯地址，邮政编码。
有二位或多位作者，则每一不同的地址应按之中出现的先后顺序列出，并以相应上标符号的形式列出与相应作者的关系。
如果第一作者不是通讯作者，作者应该按期刊的相关规定表达，并提前告诉编辑。
期刊大部分以星号(*)、脚注或者致谢形式标注通讯联系人。
3)挑选审稿人的几个途径：很多SCI杂志都需要作者自己提出该篇论文的和您研究领域相关的审稿人，比较常见的是三名左右，也有的杂志要求5-8人。
介绍几个方法：①利用SCI、SSCI、A&HCI、ISTP检索和您研究相关的科学家;②文章中的参考文献;③相关期刊编委或学术会议的主席、委员;④以前发表的类似文章的审稿人;⑤询问比较熟识的一些专业人士;⑥交叉审稿，邀请以前的作者;⑦若是团队序贯研究，斟酌考虑自建期刊审稿人专家库。
“Of Course it’s True; I Saw it on the Internet!”Critical Thinking in the internet EraLeah Graham and P. Takis MetaxasThe internet is revolutionizing research methods at colleges and universities around the world. Though the internet can be extremely useful to researchers, it presents a significant challenge as it is quite different from traditional sources. The lack of uniform standards and the ease of access have made the internet a powerful but uncertain medium. Substantial effort is required to adequately evaluate information provided on the internet, and this may not always be apparent to users. [5] This is particularly challenging for students as many have come to rely on the internet as a primary source of information without formal instruction about the difficulties involved. The internet has gained a primary place in research methods, and it is vital that students become able to critically evaluate information on the internet.Several solutions have been suggested to facilitate accuracy determination in internet research. In Libraries and the Academy, Jerry Campbell argues in support of the Association of Research Libraries’ plan to develop an internet portal to “trustworthy” information. [1] This portal would “promote the development of and provide access to the highest quality content on the Web.” Many colleges have also adopted this approach by providing lists of “approved” online sources to students. While it appears to provide a practical alternative to “s” that focus more on advertising than accuracy, this approach suffers from several drawbacks. First, it is impossible to continually monitor all of the content found using these portals. Websites change overnight and expand at exponential rates, and attempting to verify every page of each linked site every day would be an incredibly time-consuming task. Clearly, this is not feasible, but it would be necessary to ensure the accuracy and timeliness expected of information found using a “scholars’ portal.” Additionally, this approach places∗ Corresponding author’s address: Department of Computer Science, Wellesley College, Wellesley, MA 02481the responsibility of evaluation on the webmasters of these portals. A more interactive approach that encourages users to develop critical thinking skills would provide lasting value, while preventing them from becoming dependent on these portals for the “right answers.”Developing other approaches requires a firm understanding of how students currently use the internet for research. Consider the results of an informal questionnaire distributed at SUNY College of Agriculture and Technology in Morrisville, New York, by Angela Weiler in 1999. In response to a question asking how students would ascertain if online sources were accurate enough to be considered “a good source of information,” 29% said they accepted internet information regardless, with only 34% considering additional verification important.[5] These startling results confirm the importance of further study to provide specific information about students’ online research practices. To address this, we developed a six-question survey that was administered to 180 Wellesley College students during the 2000-2001 academic year. Students’ responses to this survey helped explain how college students, from different backgrounds, class years, and majors, react to information on the internet.Research MethodsThe students participating in this study were in Computer Science 110 (“Computers and the Internet”), and this survey was their first assignment. Students were told the purpose of the survey was to understand how students conducted searches. The survey was divided into seven emails. The first explained the process of responding to the survey and included a personal information questionnaire. The following six emails each contained one question and asked students to report their answer and search strategies.The survey was designed to answer three research questions:•First, how strongly do students rely on the internet for information?•Second, what claims are students more likely to believe?•And finally, who is most susceptible to misleading claims?To identify students’ reliance on the internet, they were told to answer the questions in whatever way they wished. They were free to use any resource available, and they were askedto report which search methods were used for each question.The six survey questions were used to determine students’ ability to evaluate information, as well as their inclination to verify their responses. Four questions tested particular areas of misinformation: advertising claims, government misinformation, lobby group propaganda, and ‘scams.’ Preliminary research indicated these areas could present a significant challenge to students. Two additional questions—one very easy and one very difficult—were used to determine if students were more diligent about accuracy and verification when the information was easy to find.Each response was given a score from 0-3, with 3 being the highest score. The scoring system placed equal weight on accuracy and the students’ efforts to double-check responses.An optimal answer was therefore defined as a correct response confirmed in at least two sources. Other scores were categorized as follows:A 0 indicates no response, a 1 an incorrectresponse that was not double-checked, and a 2either a correct answer that was not double-checked or an incorrect response that wasdouble-checked. The 2 category contains bothtypes of responses, as dividing the categorywould require placing more importance onaccuracy or verification. Neither of theseattributes, when considered individually, wholly constitutes adequate research practices. As such, the 2 category remains the “middle” category for responses that are not entirely acceptable due to a lack of accuracy or verification.Finally, to evaluate which groups of students are in greater need of assistance, students were asked to fill out a questionnaire asking for age, class year, and other factors. These data were matched with their responses to the survey questions.- Table 1 -ResultsThe conclusions to these research questions were remarkable. Regarding students’reliance on the internet, it became apparent that students are very eager to use the internet—and only the internet—in conducting research. Though the survey was not in any way limited to internet resources, less than 2% of students’ responses to all questions included non-internet sources. Many of these responses also quoted online sources at some point. This finding emphasizes the importance of teaching good internet research skills, as students rely so heavily on the internet.This survey also revealed the extraordinary confidence students have in search engines. If the question did not mention a particular website, almost all students immediately turned to a search engine. Many remained faithful to one search engine throughout the survey, even if it did not immediately provide the answer sought. This is particularly interesting as experts believe that no single search engine captures more than 16% of the entire internet. With all search engines combined, this only increases to 42%. [2] Additionally, students were asked a question in the personal information questionnaire to determine the extent of their understanding of search engines. Few students responded with any degree of awareness of the process by which search engines post results. This is distressing as the reliability of search engines to faithfully and selflessly guide users to appropriate materials has often been questioned. [8]The second research question about the types of information that are most problematic to students yielded disheartening results. Students were overwhelmingly susceptible to three types of misinformation—advertising claims, government misinformation, and propaganda—and somewhat susceptible to scam sites.The two most successful misleading claims were advertising and government misinformation. To study the impact of advertising claims, students were asked this question:“List three major innovations developed by Microsoft over the past ten years.” The term “major innovation” was left vague, as Microsoft’s innovative history is a widely debatedissue. There are many opinions on the topic, and we expected students overall to discuss at least several.However, 63% of students respondedthat Microsoft was responsible for many majorinnovations based on information from onlyone source. Almost all of these studentsimmediately went to the Microsoft website andused the Microsoft Museum Timeline thatdetails Microsoft’s achievements—or at least,what Microsoft claims to be its achievements.Only 12% checked several sources and madesome more complete argument about this. 22%fell in between these two groups, receiving a score of 2. These results are intriguing in view of recent litigation against Microsoft that drew worldwide attention to its business practices and innovative efforts. Yet almost two-thirds of students responded without a shadow of a doubt that Microsoft was completely honest about its claims.Government misinformationfollowed closely behind advertisingclaims. Students were asked: “Did the1999 Rambouillet Accords allowNATO to operate in all of Yugoslaviaor only in Kosovo?” The correctanswer—all of Yugoslavia—can befound in the actual document, though itis difficult to wade through the 82-pagepaper. The complete text can be found online, but summaries and reviews are much more common. A frequently found summary is the U.S. Department of State Bureau of European Affairs fact sheet released on March 1,1999, which implies that NATO presence is limited to Kosovo. [7]- Figure 1 -- Figure 2 -62% of students said that NATO is limited to acting within Kosovo based on one source, and many listed the State Department memo mentioned above as their only source.26% said the same thing but made some effort to double-check the information or happened to find the right answer on the first try. Many students in this category stumbled on anti-NATO websites and reported that information without checking another less-biased source.Only 10% found the correct answer and verified it in two places.Political lobby groups are another common source of misinformation or half-truths.Students were asked to evaluate a claim made by . This website is the work of an anti-smoking lobby, though it is officially copyrighted by the Massachusetts Department of Public Health. Students were asked: “ says that tobacco is responsible for 30% of all deaths in the 35-69 age group. Would you cite this information in a research paper?” This statistic, taken from a pamphlet called “Growing Up Tobacco Free,”is actually a projection made in 1992 on how many deaths tobacco will probably cause in the 1990s, but lists this as if it were proven fact. [3] The number of deaths is actually estimated to be closer to 20% by organizations such as the American Cancer Society and the U.S. Center for Disease Control and Prevention. [6]Despite this, 48% of students said that they notonly believed the statistic from but that they wouldconfidently cite it in a research paper. They didnot attempt to find a corroborating source. Only21% expressed reluctance to use thisinformation after checking with additionalsources, with 30% falling in between with ascore of 2. What is most disturbing is that manyof the students who readily believed this statistic realized that the site was probably the product of an anti-smoking lobby, but the fact that it was sponsored by the Massachusetts Department of Public Health reassured them.- Figure 3 -Students seemed to believe that because a source was cited and the Massachusetts government copyrighted the website, the statistic would naturally be accurate.Fortunately, the results are not entirely dim. Students were much less susceptible to the scam website. They were asked to evaluate ’s ‘revolutionary’ product Vespro GHS containing Human Growth Hormone (hGH), an emerging medical treatment to combat the effects of aging. According to the website, this product will decrease body fat, reduce wrinkles, restore lost hair, and normalize blood pressure, among a variety of other benefits—an absolute miracle drug. This website provides quotes from medical journals that are generally taken out of context to support its claims. For instance, there is a quote from a 1989 article in the New England Journal of Medicine that seems to support the beneficial effects of hGH, though the conclusion of this article simply states that further research is necessary. [4]Students were asked: “Wouldyou recommend Vespro Life Science’shGH product to a friend concernedabout getting older?” Only 13% ofstudents immediately agreed torecommend this product, withoutconsulting another source. 35% ofstudents conducted further research andreported that they would not recommendthis product without more information.52% of students received a score of 2. Though these results are not overly encouraging, they demonstrate that students remain skeptical of this type of information on the internet.The remaining two questions were used to determine students’ inclination to verify information. Students were asked one easy and one hard question. The first question asked students to report the creator of Linux. The answer is easily found in minutes online. The second asked students to find the land area of Lisbon, Portugal. While this sounds elementary,- Figure 4 -it can take a tremendous amount of time to locate any answer on the internet, and even longer to find a second source. For the easy Linux question, 78% of students reported the first answer they found, without verifying it in another source. For the hard Lisbon question, 75% of students reported the first answer they found without double-checking. It appears that students are just as likely to avoid verifying an answer, regardless of the time or effort needed to do so.Finally, to determine which groups of students are more susceptible to misleading claims, responses to the personal information questionnaire were matched with answers to the six survey questions. Using class year, we hoped to see if students became better internet researchers over the course of their years at Wellesley. The results indicate that there was no significant difference in performance based on class year.- Table 2 -We then looked at students’ self-reported confidence in their internet searching abilities to determine if students who were more “internet-savvy” were better able to critically evaluate information on the internet. The categories available were very confident, fairly confident, slightly confident and not very confident. The following chart indicates the total number of scores (0-3) given to students in each confidence level.- Table 3 -Notice that the distribution of scores for all questions is very similar for each confidence level. Only the not very confident group shows notable, though not overly large, differences. This suggests that the confidence a student has in her abilities to search the internet effectively does not significantly affect her performance.ConclusionsClearly, students consider the internet a primary source of information. The results presented here suggest that many students have trouble recognizing trustworthy sources, though perhaps the underlying problem is a lack of understanding of the internet as an unmonitored well of information. All future educational ventures must focus on teaching users that the internet is unmonitored method of sharing information. Specifically, this instruction should equip users to use search engines effectively, and this requires an awareness of their technological and financial constraints. This is not to recommend teaching students that all search engines are devoid of useful information, but rather to promote a better understanding of the actual service provided by search engines.Students are also not consistently able to differentiate between advertising and fact. Many responses to mentioned that as the website was just trying to sell a product, its claims could not be readily believed. However, many of these same students immediatelybelieved claims made by Microsoft on its commercial website. Students must understand that all information on the internet is there for a reason, and it is vital to determine the purpose of the information when evaluating its accuracy.The very small amount of students who double-checked information is also of concern. It is commonly believed that the triangle method—locating three independent sources that point to the same answer—produces the most accurate information. This approach does not differentiate a great deal between “good” and “bad” sites, but rather encourages users to double-check information regardless of the source. Students in this study seemed to have a great deal of confidence in their abilities to distinguish the good sites from the bad. Colleges themselves often encourage this attitude as they determine “good” or “trustworthy” websites to help students begin internet research. While it is certainly useful to provide guidance, it is equally important to promote the development of critical thinking skills that will allow students to make use of the entire internet, rather than a few “approved” sites.Our findings also suggest that students across the board have similar difficulties in carefully evaluating information found on the internet. Older students with stronger traditional research skills performed no better than other students, which suggests that these skills are simply not sufficient when evaluating information on the internet. In the past, the greatest problem facing researchers was finding information; now, with the advent of the internet, the greatest problem is evaluating the vast wealth of information available. Students in this survey placed greater emphasis on the process of finding an answer than on analyzing the actual information. The difficulties students encountered suggest that this practice is of little use in determining the accuracy of online information. It is therefore important to develop specific research practices for internet searches that take into account the structure and purpose of the internet.As students continue to view the internet as a primary source of information, without a significant shift in training methods, this problem will only grow worse. It is vital that they better understand the nature of the internet and develop an instinctive inclination for verifyingall information. This will allow students to take advantage of the tremendous benefits provided by the internet without falling prey to the pitfalls of online research.References1. Campbell, Jerry. “The Case for Creating a Scholars Portal to the Web: A White Paper.”Libraries and the Academy. 1.1, 2001.2. Introna, Lucas & Nissenbaum, Helen. “Defining the Web: The Politics of Search Engines.”IEEE, 2000.3. Lynch, Barbara S. & Bonnie, Richard J., eds. “Growing Up Tobacco Free: PreventingNicotine Addiction in Children and Youths.” Washington, D.C.: National AcademyPress, 1994.4. Salomon, F. et al. “The Effects of Treatment with Recombinant Human Growth Hormoneon Body Composition and Metabolism in Adults with Growth Hormone Deficiency.”New England Journal of Medicine. 321:26, 28 December 1989.5. Weiler, Angela. “Two-Year College Freshmen and the Internet: Do they really ‘know all that stuff?’” Libraries and the Academy. 1.2, 2001.6. “Cigarette Smoking Related Mortality.” Centers for Disease Control and Prevention.United States, 1990. Morbidity and Mortality Weekly Report 1993; 42 (33): 645-8;/tobacco/research_data/health_consequences/mortali.htm7. “Understanding the Rambouillet Accords.” Fact sheet released by the Bureau of EuropeanAffairs, U.S. Department of State, Washington, D.C., 1 March 1999;/www/regions/eur/fs_990301_rambouillet.html8. See, for example, “Defining the Web: The Politics of Search Engines” (Introna &Nissenbaum, IEEE, 2000), “Information Retrieval on the World Wide Web”(Gudivada et al., IEEE, 1997), and “Searching the World Wide Web” (Knoblock,IEEE Expert, January-February 1997).11。
SCI收录期刊英文投稿全过程英文信件模板一览一、最初投稿Cover letterDear Editors:We would like to submit the enclosed manuscript entitled “Paper Title”, which we wish to be considered for publication in “Journal Name”. No conflict of interestexits in the submission of this manuscript, and manuscript is approved by all authors for publication. I would like to declare on behalf of my co-authors that the work described was original research that has not been published previously, and not under consideration for publication elsewhere, in whole or in part. All the authors listed have approved the manuscript that is enclosed.In this work, we evaluated …… (简要介绍一下论文的创新性). I hope this paper is suitable for “Journal Name”.The following is a list of possible reviewers for your consideration:1) Name A E-mail: ××××@××××2) Name B E-mail: ××××@××××We deeply appreciate your consideration of our manuscript, and we look forward to receiving comments from the reviewers. If you have any queries, please don’t hesitate to contact me at the address below.Thank you and best regards.Yours sincerely,××××××Corresponding author:Name: ×××E-mail: ××××@××××二、催稿信Dear Prof. ×××:Sorry for disturbing you. I am not sure if it is the right time to contact you to inquire about the status of my submitted manuscript titled “Paper Title”. (ID: 文章稿号), although the status of “With Editor” has been lasting for more than two months, since submitted to journal three months ago. I am just wondering that my manuscript has been sent to reviewers or not?I would be greatly appreciated if you could spend some of your time check the status for us. I am very pleased to hear from you on the reviewer’s comments.Thank you very much for your consideration.Best regards!Yours sincerely,××××××Corresponding author:Name: ×××E-mail: ××××@××××三、修改稿Cover letterDear Dr/ Prof..（写上负责你文章编辑的姓名，显得尊重，因为第一次的投稿不知道具体负责的编辑，只能用通用的Editors）:On behalf of my co-authors, we thank you very much for giving us an opportunity to revise our manuscript, we appreciate editor and reviewers very much for their positive and constructive comments and suggestions on our manuscript entitled “Paper Title”. (ID: 文章稿号).We have studied reviewer’s comments carefully and have made revision which marked in red in the paper. We have tried our best to revise our manuscript according to the comments. Attached please find the revised version, which we would like to submit for your kind consideration.We would like to express our great appreciation to you and reviewers for comments on our paper. Looking forward to hearing from you.Thank you and best regards.Yours sincerely,××××××Corresponding author:Name: ×××E-mail: ××××@××××四、修改稿回答审稿人的意见（最重要的部分）List of ResponsesDear Editors and Reviewers:Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Paper Title” (ID: 文章稿号). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hopemeet with approval. Revised portion are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:Responds to the reviewer’s comments:Reviewer #1:1. Response to comment: (……简要列出意见……)Response: ××××××2. Response to comment: (……简要列出意见……)Response: ××××××。
corresponding author
corresponding author译为“通讯作者”。
“通讯作者”往往指课题的总负责人，承担课题的经费、设计，文章的书写和把关，对论文内容的真实性、数据的可靠性、结论的可信性、是否符合法律规范、学术规范和道德规范等方面负全责（或主要负责），在读研究生撰写的论文，一般由其导师担任“通讯作者”。
一般情况下，除了通讯作者往往指课题的总负责人，他要负责与编辑部的一切通信联系和接受读者的咨询等外，通讯作者多数情况和第一作者是同一个人，这样的话实际上是省略了通讯作者，只有在通讯作者和第一作者不一致的时候，才有必要加通讯作者。
我不赞成一味地模仿国外杂志，加不加通讯作者应根据需要而定。
国外影响因子比较高的几个外文期刊关于“通讯作者”的定义是：通讯作者必须是文内作者之一，其作用为稿件的通信联系，也就是起联系人的作用。
国外期刊的通讯作者主要是负责联络沟通和论文的学术解释，保证论文的学术真实性。
“通讯作者”通常应该具有更高的学术地位以及专业水平，在该项科研工作中以第一作者的指导老师或重要辅导专家的身份为其提供帮助。
如何回复SCI投稿审稿人意见（精典语句整理）如何回复SCI投稿审稿人意见1.所有问题必须逐条回答。
2.尽量满足意见中需要补充的实验。
3.满足不了的也不要回避，说明不能做的合理理由。
4.审稿人推荐的文献一定要引用，并讨论透彻。
以下是本人对审稿人意见的回复一例，仅供参考。
续两点经验：1. 最重要的是逐条回答，即使你答不了，也要老实交代；不要太狡猾，以至于耽误事；2. 绝大部分实验是不要真追加的，除非你受到启发，而想改投另外高档杂志----因为你既然已经写成文章，从逻辑上肯定是一个完整的“story” 了。
以上指国际杂志修稿。
国内杂志太多，以至于稿源吃紧，基本没有退稿，所以你怎么修都是接受。
我的文章水平都不高，主要是没有明显的创新性，也很苦恼。
但是除了开始几篇投在国内杂志外，其他都在国际杂志（也都是SCI）发表。
以我了解的情况，我单位其他同志给国内杂志投稿，退稿的极少，只有一次被《某某科学进展》拒绝。
究其原因，除了我上面说的，另外可能是我单位写稿子还是比较严肃，导师把关也比较严的缘故。
自我感觉总结（不一定对）：1）国内杂志审稿极慢（少数除外），但现在也有加快趋势；2）国内杂志编辑人员认真负责的人不多，稿子寄去后，少则几个月，多则一年多没有任何消息；3）国内杂志要求修改的稿子，如果你自己不修，他最后也给你发；4）国外杂志要求补充实验的，我均以解释而过关，原因见少帖）。
还因为：很少杂志编辑把你的修改稿再寄给当初审稿人的，除非审稿人特别请求。
编辑不一定懂你的东西，他只是看到你认真修改，回答疑问了，也就接受了（当然高档杂志可能不是这样，我的经验只限定一般杂志（影响因子1-5）。
欢迎大家批评指正。
我常用的回复格式:Dear reviewer:I am very grateful to your comments for the manuscript. According with your advice, we amended the relevant part in manuscript. Some of your questions were answered below.1）....引用审稿人推荐的文献的确是很重要的，要想办法和自己的文章有机地结合起来。
American Society for Pharmacology and Experimental Therapeutics Authorship Responsibility, Financial Disclosure, and Chemical Structure Statement Form for The Journal of Pharmacology and Experimental TherapeuticsManuscript title:Corresponding author:Telephone number: Fax number:Address:E-mail Address:Each author must read and sign below indicating their certification of the following statements: (1) authorship responsibility and (2) financial disclosure. If necessary, copy this document and distribute to coauthors for their signature. Please compile all forms and include them with the manuscript at the time of submission. Photocopy, facsimile, electronic, or other copies shall have the same effect for all purposes as an ink-signed original.1. Authorship Responsibility(a) I certify that I have participated sufficiently in the conception and design of this work, the analysis of the data (where applicable), as well as the writing of this manuscript, to take public responsibility for it. I believe the manuscript represents valid work. I have reviewed this manuscript and approve its submission. If I am listed above as corresponding author, I will provide all authors with information regarding this manuscript and will obtain their approval before submitting any revision. All of the appropriate individuals are named as authors of this work. Neither this manuscript nor one with substantially similar content under my authorship has been published or will be submitted for publication elsewhere while under consideration by The Journal of Pharmacology and Experimental Therapeutics, except as described in an attachment. Furthermore, I attest that I shall produce the data on which the manuscript is based for examination by the editors or their assignees should they request it.(b)All authors must designate their specific contributions to the published work using the check boxes below each signature. This information is to be included as a footnote in the manuscript and will be published in the accepted paper. An individual author may be listed as having made more than one contribution, and more than one author may have contributed to the same aspect of the work.Printed Author Name Printed Author NameAuthor Signature Date Author Signature Date☐Participated in research design ☐Participated in research design☐Conducted experiments ☐Conducted experiments☐Contributed new reagents or analytic tools ☐Contributed new reagents or analytic tools☐Performed data analysis ☐Performed data analysis☐Wrote or contributed to the writing of the manuscript ☐Wrote or contributed to the writing of the manuscriptPrinted Author Name Printed Author NameAuthor Signature Date Author Signature Date☐Participated in research design ☐Participated in research design☐Conducted experiments ☐Conducted experiments☐Contributed new reagents or analytic tools ☐Contributed new reagents or analytic tools☐Performed data analysis ☐Performed data analysis☐Wrote or contributed to the writing of the manuscript ☐Wrote or contributed to the writing of the manuscript Printed Author Name Printed Author NameAuthor Signature Date Author Signature Date☐Participated in research design ☐Participated in research design☐Conducted experiments ☐Conducted experiments☐Contributed new reagents or analytic tools ☐Contributed new reagents or analytic tools☐Performed data analysis ☐Performed data analysis☐Wrote or contributed to the writing of the manuscript ☐Wrote or contributed to the writing of the manuscript Printed Author Name Printed Author NameAuthor Signature Date Author Signature Date☐Participated in research design ☐Participated in research design☐Conducted experiments ☐Conducted experiments☐Contributed new reagents or analytic tools ☐Contributed new reagents or analytic tools☐Performed data analysis ☐Performed data analysis☐Wrote or contributed to the writing of the manuscript ☐Wrote or contributed to the writing of the manuscript2. Financial DisclosureI certify that any affiliations with or involvement (either competitive or amiable) in any organization or entity with a direct financial interest in the subject matter or materials discussed in the manuscript (e.g., employment, consultancies, stock ownership, honoraria, expert testimony, etc.) are noted below. All financial research or project support is identified in an acknowledgment in the manuscript. Statement of Financial Interest: (Check none or list. If more space is needed, submit a signed attachment.)☐ None3. Chemical Structure☐I certify that the chemical structure of all new compounds cited or discussed in the Work is presented or a citation to the published structure is provided, in accordance with the journal’s editorial policy.American Society for Pharmacology and Experimental TherapeuticsCopyright Transfer Form forThe Journal of Pharmacology and Experimental TherapeuticsManuscript title:Corresponding author:Telephone number: Fax number:Address:E-mail Address:Each author must read and sign below indicating their certification of (a) copyright assignment or (b) federal employment. If necessary, copy this document and distribute to coauthors for their signature. Please compile all forms and include them with the manuscript at the time of submission. In the case of a “work made for hire,” the agreement must also be signed by an authorized agent of the Employer. This agreement shall be effective when signed below or in counterpart, and photocopy, facsimile, electronic, or other copies shall have the same effect for all purposes as an ink-signed original.Check either (a) or (b)(a) Copyright Assignment. In consideration of The American Society for Pharmacology and Experimental Therapeutics (“TheOwner”) reviewing, editing, and publishing this submission (“The Work”) in The Journal of Pharmacology and Experimental Therapeutics when and if the Work is accepted for publication, the undersigned author(s) (“The Authors”) or, where the Work is a “work made for hire” for an employer (“The Employer”), the Employer agrees to the following terms, as established by the Board of Publications Trustees of the Owner.A. The Author or, if applicable, the Employer, hereby grants and assigns to the Owner or its successors, all rights of any kind to the Work, including those protected by the copyright laws of the United States or any foreign country.B. The Author or, if applicable, the Employer, warrants that his/her contribution is original; that he/she has full power to make this grant; that the Work contains no libelous or otherwise unlawful matter; and either that the Work has not been previously published or, if portions have been previously published, that permission has been obtained for publication and he/she will submit a copy of the permission release and language for credit lines with his/her manuscript.C. An individual author will be given the right by the Owner, upon request, to use part of his/her Work for any scholarly or academic purpose, such as use for instructional purposes or incorporation as part of another and different publication where the copyrighted material may be desired for illustration or explanation, provided lawful notice of copyright is given.D. Where the copyrighted Work was “work done for hire,” as defined by the copyright law, the employing organization will be given theright by the Owner, upon request, to use the copyrighted material where it will be presented in its entirety, provided lawful notice of copyright is given.E. Where the employing organization or an individual author desires to use only a portion of the Work that has been copyrighted and that use is for promotional or advertising purposes, the Owner will not grant permission for the use of the copyrighted material.F. The Owner agrees that subsequent to the publication of the article, if, after written request to the printer of the copyrighted work, or such other printer as the Owner may direct, reprints of the entire Work cannot be reproduced and delivered to the Author, or if applicable, the Employer within 60 days following such written request, such Author or Employer, as the case may be, is given the right without further request to have such copyrighted work reproduced in its entirety.G. The Owner may grant third parties permission to copy all or part of the Work. If such permission is given, the Owner will, as a matter of courtesy, and not as a matter of contract, advise the Author or Employer of such permission.H. Neither Author nor Employer will receive any royalty or other monetary compensation from the Owner or the Publisher for the rights transferred by this Agreement.I. Notwithstanding anything to the contrary herein above contained, this Agreement applies to the publication of the “Work” and does not impinge upon the rights of any resulting patentable inventions or design rights, which remain with the Author(s) or the Employer.J. In the case of a Work supported by funding from the National Institutes of Health (NIH), the Owner will deposit the final version of theWork with PubMed Central on behalf of the Author(s) with public release at PubMed Central 12 months after publication of the final version of the Work in The Journal of Pharmacology and Experimental Therapeutics.K. In the case of a Work supported by funding from the Wellcome Trust, the Howard Hughes Medical Institute, or the UK Research Councils, the Owner will deposit the final version of the Work with PubMed Central on behalf of the Author(s) with public release 6 months after publication of the final version of the Work in The Journal of Pharmacology and Experimental Therapeutics . L. If all or part of the Work was prepared under a contract with the U.S. Government, state contract number:(b) U.S. Federal Employment: This is to certify that the Work was written by an officer or employee of the U.S. Government as part ofhis/her official duties, and therefore it is not subject to U.S. copyright. This statement must be also signed by an authorized Government agency representative.Printed Author NameAuthor Signature DatePrinted Author Name EmployerAuthor Signature Date TitlePrinted Author Name Signature DateAuthor Signature Date AgencyPrinted Author Name TitleAuthor Signature Date SignatureDatePrinted Author NameAuthor Signature DatePrinted Author NameAuthor Signature DatePrinted Author NameAuthor Signature DatePrinted Author NameAuthor SignatureDateUse an additional sheet for additional authors. Signature, date, and printed name are required for each author.。
Decadal variability in the Kuroshio-Oyashio Extension simulated inan eddy-resolving OGCMMasami Nonaka,Frontier Research Center for Global Change, JAMSTEC, Yokohama, JAPANHisashi Nakamura,Frontier Research Center for Global Change, JAMSTEC, Yokohama, JAPANalso Graduate school of Science, the University of Tokyo, Tokyo, JAPANYouichi Tanimoto,Frontier Research Center for Global Change, JAMSTEC, Yokohama, JAPAN also Faculty of Environmental Earth Science, Hokkaido University, Sapporo, JAPANTakashi Kagimoto,Frontier Research Center for Global Change, JAMSTEC, Yokohama, JAPANHideharu SasakiThe Earth Simulator Center, JAMSTEC, Yokohama, JAPANSubmitted to the Journal of ClimateMay 16, 2005Revised on Aug. 17, 2005Corresponding author address:Masami NonakaFrontier Research Center for Global Change,Japan Agency for Marine-Earth Science and Technology (JAMSTEC)3173-25 Showa-machi, Kanazawa-ku, Yokohama, 236-0001 Japannona@jamstec.go.jp1ABSTRACTThrough analysis of a hindcast integration of an eddy-resolving quasi-global ocean general circulation model, decadal variability in the Kuroshio-Oyashio Extension region is investigated, with particular emphasis on that of the subarctic (Oyashio) and the Kuroshio Extension (KE) fronts. The KE front is deep and accompanied by sharp sea surface height (SSH) gradient with modest sea surface temperature (SST) gradient. In contrast, the subarctic front is shallow and recognized as a zone of tight gradient in SST but not SSH.As a decadal-scale change from a warm period around 1970 to a cool period in the mid-1980s, those fronts in the model migrate southward as observed, and the associated pronounced cooling is confined mainly to those frontal zones. Reflecting the distinctive vertical structures of the fronts, the mixed-layer cooling is the strongest along the subarctic front, whereas the subsurface cooling and the associated salinity changes are the most pronounced along the KE front. Concomitantly with their southward migration, the two fronts have undergone decadal-scale intensification. Associated with reduced heat release into the atmosphere, the cooling in the frontal zones can be attributed neither to the direct atmospheric thermal forcing nor to the advective effect of the intensified KE current, while the advective effect by the intense Oyashio can contribute to the cooling in the subarctic frontal zone.In fact, their time evolution is not found completely coherent, suggesting that their variability may be governed by different mechanisms. Decadal SSH variability in the KE frontal zone seems to be largely explained by propagation of baroclinic Rossby waves forced by anomalous Ekman pumping in the central North Pacific. This process alone cannot fully explain the corresponding variability in the subarctic frontal zone, where eastward propagating SSH anomalies off the Japanese coast seem to be superimposed on the Rossby wave signals.21.IntroductionSince the pioneering works by Nitta and Yamada (1989) and Trenberth (1990), it has been established that the North Pacific (e.g., Tanimoto et al. 1993; Graham 1994; Kawamura 1994; Trenberth and Hurrell 1994) and the pan-Pacific (e.g., Zhang et al. 1997; Mantua et al. 1997) atmosphere-ocean coupled systems fluctuate on decadal and interdecadal time scales. One of the most prominent phase changes of the decadal variability over the Pacific Ocean occurred around 1977, which is called as a “climate shift” by some researchers. In association with the change, the tropical Pacific and the eastern North Pacific was warmed (e.g., Graham 1994), while sea surface temperature (SST) in the central North Pacific dropped significantly in association with intensified Aleutian low and surface westerlies.Recent studies have revealed that the western North Pacific, more specifically, the so-called Kuroshio-Oyashio Extension (KOE) region is one of the primary centers of action of the decadal SST variability (Nakamura et al. 1997; Schneider et al. 2002; Schneider and Cornuelle 2005). From a macroscopic view the KOE region is a zonally oriented SST frontal zone associated with strong eastward surface currents, forming the boundary of the oceanic subtropical and the subpolar gyres (e.g., Yasuda et al. 1996). Detailed investigations have shown that SST anomalies (SSTAs) in the KOE region (more specifically, the subarctic frontal zone) associated with decadal variability exhibit no significant simultaneous correlation with those either in the subtropical central North Pacific (specifically, in the subtropical frontal zone) or in the tropical Pacific (Nakamura et al. 1997; Nakamura and Yamagata 1999; Tomita et al. 2001). Rather, SSTAs in the subarctic frontal zone tends to lag by about five years to those in the subtropical frontal zone (Miller and Schneider 2000).It has also been argued that air-sea interaction in the KOE region has the potential to force (Latif and Barnett, 1994) or intensify (Barnett et al. 1999; Pierce et al. 2001; Schneider et al.2002) the decadal variability in the North Pacific. Concerning the atmospheric responses to the3midlatitude SSTAs that are necessary for the interaction, however, atmospheric generalcirculation model studies have still failed to show coherent responses and most of observed data analyzing studies have shown dominance of atmospheric forcing to SSTAs in most of the extratropics (Kushnir et al. 2002, for recent review). Nevertheless, recent analyses of observed data have suggested the existence of the ocean-to-atmosphere feedback in the KOE region (Nonaka and Xie 2003; Tanimoto et al. 2003).In addition to the atmospheric response, how decadal-scale SSTAs are induced in the KOE region also needs to be clarified. It is well known that wintertime SSTAs are primarily forced by the atmospheric variability through surface heat flux anomalies in most of the central and eastern North Pacific (e.g., Cayan 1992; Alexander 1992). However, it has recently been shown by oceanic general circulation model (OGCM) studies (Xie et al. 2000; Yasuda and Kitamura 2003) and suggested by observational studies (Qiu 2000; Tomita et al. 2002; Kelly and Dong 2004) that SSTAs in the KOE region can be generated through oceanic dynamics.Three mechanisms have been proposed on the generation of decadal-scale SSTAs in the KOE region. First, Latif and Barnett (1994) proposed that anomalous warm-water transport from the tropics by the Kuroshio and its extension current associated with spin-up/spin-down of the subtropical gyre induces SSTAs in the KOE region. This mechanism is consistent with an analysis by Qiu (2000) of the heat budget in the Kuroshio Extension (KE) region based on observational data. Second, propagation of oceanic Rossby waves forced by anomalous wind stress curl (and associated Ekman pumping) can induce perturbations in the thermocline depth within the KOE region (Masuda 2003), producing SSTAs there (Schneider and Miller 2001). Third, Seager et al. (2001) suggested through their analyses of an OGCM output and observed data that meridional migration of the KOE SST front can be caused by propagation of wind induced Rossby waves that have been forced by Ekman pumping anomalies around the boundarybetween the gyres. The last two hypotheses can explain the five-year lag observed between4decadal-scale SSTAs in the central North Pacific and the KOE region as the traveling time of theRossby waves (Seager et al. 2001; Schneider et al. 2002).In the previous studies mentioned above, the analyzed data that are based on a paucity of observations or OGCM integrations under limited computational resources have rather coarse horizontal resolutions for basin-scale temperature changes. The resolutions of those data, however, are not high enough to resolve the complex structure of the KOE frontal zone, as suggested by satellite data (Nakamura and Kazmin 2003). In fact, detailed analyses of observed temperature fields have revealed that there are at least two prominent fronts in the KOE region: the KE front along the KE current (e.g., Mizuno and White 1983) and the subarctic (Oyashio) front associated with the Oyashio Extension current (e.g., Yuan and Tally 1996). Those two fronts are meridionally separated by the Kuroshio-Oyashio mixed water region (Yasuda et al. 1996, and references therein). Variability of the two fronts could be governed by different dynamics, and if so, they would not necessarily vary in a coherent manner as simulated in the GCM experiments with coarse horizontal resolutions in the previous studies.In this study, we investigate how each of the fronts in the KOE region changes in association with decadal basin-scale variability in the North Pacific and how well the mechanisms currently proposed for the North Pacific decadal variability can be applied to the KOE region. Our analysis is based on a hindcast OGCM experiment performed on the Earth Simulator (Ohfuchi et al. 2005), whose high computational performance allows us to integrate the model over 54 years with such a high resolution as to resolve the separation of those two fronts adequately. Our analyses indicate that the strongest decadal-scale temperature anomalies simulated in the surface (subsurface) layer are generated in association with decadal changes in the subarctic (KE) fronts, indicating the primary importance of oceanic processes in inducing the thermal anomalies there.The paper is organized as follows. Section 2 describes the model and datasets. Section 3compares our OGCM fields with observations. Section 4 presents typical anomalies in the5temperature field and the fronts associated with the North Pacific decadal variability. Temporal developments of the decadal anomalies are also reported there. Section 5 discusses some mechanisms for the changes. Section 6 provides a summary.2. Model and datasetsa. The OFESThe OGCM we use in this study is the Modular Ocean Model (MOM3) (Pacanowski and Griffies, 2000), developed at the Geophysical Fluid Dynamics Laboratory/National Ocean and Atmospheric Administration (GFDL/NOAA). The code has been substantially modified for attaining its efficient performance on a vector-parallel hardware system of the Earth Simulator. Our ocean model for the Earth Simulator (OFES; Masumoto et al. 2004) covers a near-global domain extending from 75°S to 75°N, except for the Arctic Ocean, with horizontal resolution of 1/10°. The model has 54 vertical levels, with resolutions from 5 m at the surface to 330 m near the bottom. The model topography is based on the 1/30° bathymetry dataset (kindly provided by GFDL/NOAA) with the maximum depth of 6,065 m.The model solves the primitive equation system in spherical coordinates under the Boussinesq and hydrostatic approximations. The KPP boundary layer mixing scheme (Large et al. 1994) is adopted for vertical mixing. For horizontal mixing of momentum and tracers, we adopt a scale-selective damping with a bi-harmonic operator, to suppress grid-scale computational noises (Smith et al. 2000). The background horizontal bi-harmonic viscosity and diffusivity are -27x109 m4s-1 and -9x109m4s-1, respectively. These values are the same as those used in Maltrud and McClean (2005) and Smith et al. (2000) for 0.1°-resolution global and Atlantic OGCMs, respectively, but suitability of the values and sensitivity of the solution to the values need to be explored further in future studies.In the model, the surface heat flux is calculated with the bulk formula by Rosati and6Miyakoda (1988) from atmospheric variables based on the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis (Kalnay et al. 1996). The fresh water flux is evaluated from daily precipitation rate taken from the reanalysis data, under the constraint for sea-surface salinity to be restored to its monthly climatology with time-scale of 6 days, to include the contribution from river run-off. The climatology is based on World Ocean Atlas 1998 (WOA98; Boyer et al. 1998a, 1998b, 1998c). Within 3° from the model’s artificial boundaries placed at 75°N and 75°S, temperature and salinity are restored to their local monthly climatologies (WOA98) with time scale that is 1 day at the boundaries and increasing to infinity into the interior region. See Masumoto et al. (2004) and Sasaki et al. (2005, in preparation) for details of the model set up.The model was integrated for 50 years from the climatological annual-mean fields of temperature and salinity (WOA98) without motion by applying the climatological monthly-mean atmospheric forcing for the period from 1950 to 1999 based on the NCEP/NCAR reanalysis data. Following this 50-year climatological run as the model spin-up, we conducted a 54-year hindcast integration with daily mean atmospheric fields of the NCEP/NCAR reanalysis data from 1950 to 2003. In the following analyses, model climatology and anomaly are defined as mean for this 54-year period and deviation from it, respectively.Smith et al. (2000) showed that with 0.1° horizontal resolutions mesoscale eddies should be resolved reasonably well. For our analytical convenience, however, the full resolution (0.1°) of the model output has been reduced to 0.5° resolution by picking up the data at every five grid-points both in the zonal and meridional directions. Though reduced, the resolution is still adequate for resolving fine frontal structures in the KOE region as shown below, and variability in frontal structures in the SST and sea surface height (SSH) fields discussed below is confirmed to have the same characteristics between the reduced and full resolution datasets.7b. Observational datasetsIn addition to the output of the hindcast integration of the OFES, we also use the following observed ocean temperature data products: the Japan Meteorological Agency (JMA) SST data set, Frontier Research System-Comprehensive Ocean and Atmosphere Data Set (FRS-COADS; Tanimoto and Xie 2002), White’s (1995) temperature data set, and the World Ocean Atlas 2001 (WOA2001; Stephens et al. 2002). The JMA-SST data have been compiled for the western North Pacific (100°-180°E, 0°-60°N) with 1° horizontal resolutions by JMA based on subjective analysis of in-situ and satellite observations for every 10-day period from 1950 to 19991. The FRS-COADS is a gridded dataset with 2°x2° resolution constructed for every 10-day period based on quality-controlled ship and buoy measurements that has been compiled in the Long Marine Reports in fixed length records (LMRF) of the Comprehensive Ocean-Atmosphere Dataset (COADS; Woodruff et al. 1987). We use monthly mean SST fields based on the FRS-COADS for the period from 1950 to 1995. White’s dataset contains monthly-mean temperature fields both at the sea surface and subsurface levels (20, 40, 60, 80, 120, 160, 200, 240, 300, and 400 m deep) from 1955 to 2002 with the zonal and meridional resolutions of 5° and 2°, respectively, based on hydrographic observations. The WOA2001 contains the monthly climatologies of objectively analyzed temperature data on a 1°x1° latitude-longitude grid at the standard depth levels. We also use monthly-mean SST fields based on measurements by the Advanced Microwave Scanning Radiometer (AMSR-E) on the Aqua satellite. The dataset has been produced by the Remote Sensing Systems with horizontal resolutions of 0.25°.1The JMA-SST data include satellite data since 1998, yielding a discontinuity in the data quality in that year. It has, however, little influence on our analyses because we focus primarily on earlier years in this study.83. Observed and simulated decadal variability in the northwestern Pacifica. Fine frontal structures in the KOE regionFigure 1 shows a mean SST field simulated in the OFES for a particular month and the corresponding field based on the AMSR-E measurements. This figure indicates that, with its eddy resolving resolutions, the OFES is successful in reproducing not only the separations of the Kuroshio and Oyashio Currents from the western boundary but also the meridional separation of two sharp SST fronts along with their extensions unambiguously. As in the observation (e.g., Mizuno and White 1983), the KE front in the model forms along the KE current meandering around 35°N as the eastward continuation of the Kuroshio Current off Japan. As observed, the subarctic front in the model forms around 42°N along the Oyashio Current and its extension. As revealed in satellite data (Nakamura and Kazmin 2003), these two fronts are separated by a region of relatively uniform SST into which warm and cold eddies are cut off. Although the subarctic front in the OFES appears to be too strong to the east of about 160°E compared to the AMSR-E observation, Yuan and Talley (1996, their Fig. 12) showed that SST gradient across the front often exceeds 5°C/100 km, suggesting that the simulated gradient may not necessarily unrealistic. The successful reproduction of the two fronts in the OFES gives us the first opportunity to investigate how each of the fronts varies on decadal time scales and their role in causing large-scale SSTAs in the KOE region.b. Surface and subsurface frontsFigure 2 shows meridional sections of wintertime (January-March) climatological temperature based on the OFES and WOA 2001. In the observed climatology (right panel), the KE and subarctic fronts are found around 35°N and to the north of 40°N, respectively. Though diffused perhaps due to the sparseness of subsurface observations, there are two maxima ofmeridional temperature gradient, one in the surface layer across the subarctic front and the other9between 300 and 400-m depths associated with the KE front. Obviously, the OFES (left panel) can also reproduce subsurface temperature distributions in the KOE region reasonably well, including the latitudinal positions and vertical distributions of the two fronts. In the OFES climatology, the meridional separation of the two fronts and their distinctive vertical structures are much more apparent. The KE front has a deep structure with its maximum meridional temperature gradient below the 300-m depth and relatively weak SST gradient, while the subarctic front is shallow with its maximum gradient just below the sea surface.c. Decadal-scale temperature variability in the KOE regionIn Fig. 3, five-year running mean time series of area-mean wintertime temperature in the KOE region, [35°-43°N, 140°-170°E] are compared between the observational datasets and the OFES simulation. The top panel indicates that the OFES simulation (solid curve) captures the characteristics of the observed decadal SST variability as represented in the FRS-COADS (long-dashed) and White’s (dashed) datasets, including cool periods in the early 1960s and in the mid-1980s, and warm periods around 1970 and in the 1990s. At the same time, it is also apparent that the OFES SST has a slight cooling trend throughout the integration period.The middle and bottom panels of Fig. 3 show the observed and simulated decadal variability in surface and subsurface temperature. As suggested by Deser et al. (1996) and by Schneider and Miller (2001), the decadal temperature variability in the KOE region was coherent between the surface and subsurface levels (bottom panel), and so it is in the OFES simulation (middle panel). The time series show that a pronounced cool period in the 1980s and a relatively warm period in the early 1970s are well represented in the OFES. While the profound warming in the late 1980s is well simulated in the OFES, the simulated temperature anomalies are negative in the 1990s, as opposed to the observation, in the presence of the cooling trend in the model. The decadal-scalecooling in the 1960s, which is apparent in the OFES simulation as in the FRS-COADS SST data,10is not particularly obvious in White’s data, which may be due to the paucity of observations in the early period. In short, except for the unrealistic cooling trend, the OFES can reproduce the decadal temperature variability in the KOE region not only at the surface but also in the subsurface layers.4. Decadal-scale changes in the fronts in relation to temperature anomalies in the KOE regiona. Decadal SST anomaliesIn this section, the decadal variability in the North Pacific is examined in more detail, highlighting the differences between a pair of five-winter mean fields for the 1968-72 and 1984-88 periods. These two periods correspond to the well-defined warm and cool phases, respectively, associated with the decadal variability in the KOE region, as shown in Fig. 5 of Nakamura et al. (1997). Maps of the SST difference observed and simulated over the North Pacific between the two periods are plotted in Fig. 4, superimposed on the corresponding mean SST field for the latter period. In Fig. 4, the mean and anomaly fields of SST in the OFES simulation are compared with those for the FRS-COADS data. As in the snapshot shown in Fig. 1, the mean SST field (contours) is overall reproduced well in the OFES, while a number of meso-scale structures associated with eddies and current meanders are apparent in the OFES simulation, even in its five-winter mean field. These meso-scale eddies are smoothed out completely in the observed SST field due to its lower horizontal resolution.Large-scale features of decadal-scale SST anomalies, as represented in SST differences between the two periods, are also well represented in the OFES simulation. Consistent with the previous observational studies (e.g., Tanimoto et al. 1993; Nakamura et al. 1997), well-defined cool anomalies are distributed in the western and central portions of the North Pacific with theirzonally extended cold core around 40°N, whereas warm anomalies are confined to the eastern11North Pacific off the west coast of North America. Since we chose the particular periods with the strongest SST anomalies in the KOE region (Nakamura et al. 1997), the cool anomalies in the central North Pacific are relatively weak compared to a typical SSTA pattern associated with the Pacific Decadal Oscillation (Mantua et al. 1997).In the OFES SST field, the KE and subarctic fronts are clearly separated from one another even in the five-winter mean, and the decadal anomalies in the KOE region are the strongest along the fronts. A close comparison reveals that SST gradient is stronger across the subarctic front than across the KE front, and so are the associated SST anomalies, as indicated in satellite data by Nakamura and Kazmin (2003). There are, however, some unrealistic features in the simulated SSTAs, for example, off the Chinese coast and south of Japan. The discrepancy to the south of Japan is due to Kuroshio meanders, which are not directly controlled by large-scale winds and are unrealistically simulated in the OFES.b. Decadal changes in the surface frontsThe confinement of strong SSTAs to the surface frontal zones as shown in Fig. 4 suggests that the anomalies may be associated with decadal shifts in the frontal positions. Figure 5 shows magnitudes of the horizontal SST gradient for the two five-year periods of our interest based on the OFES simulation. In each of the periods, the SST gradient is the strongest along the subarctic front around 40°N, and it is much weaker along the KE front located to its south. In the bottom panel of Fig. 5, SST gradient fields for the earlier (1968-72; contoured) and later (1984-88; shaded) periods are superimposed to illustrate decadal changes in the frontal positions. It is apparent in that panel that those two fronts both migrate southward, while somewhat intensified from the earlier to the later period. In agreement with an analysis of satellite data by Nakamura and Kazmin (2003), the subarctic front has been shifted southward 2~3° in latitude while keepingits southwest-to-northeast orientation. Meanwhile, the southwest-to-northeast orientation of the12KE front apparent in the earlier period has been changed into the more zonal orientation in thelater period. This particular change is manifested as the increasing southward shift of the frontal axis with longitude. The shift reaches as much as 5° in latitude around 165°E, suggestive of decadal changes in the KE current. The southward migration of the frontal axes mentioned above strongly suggests that the migration has induced the strong cooling tendency from the 1970s to the 1980s simulated along the fronts. Additionally, the frontal migration yields stronger SSTAs around the subarctic front than around the KE front, reflecting stronger frontal intensity of the former.To examine whether the aforementioned changes in the fronts are limited to the surface temperature field, we further look into changes in the horizontal gradient of SSH in Fig. 6 between the two periods as in Fig. 5. As opposed to the SST field in Fig. 5, the horizontal SSH gradient is much stronger across the KE front than across the subarctic front. Nevertheless, the southward migration of the two SST fronts found in Fig. 5 is also recognized in Fig. 6, indicating that the frontal changes are not limited to the surface thermal field but rather associated with changes in the gyre circulation. As in the SST field (Fig. 5), the magnitude of the SSH gradient is slightly intensified to the west of 170°E across the subarctic front (Fig. 6). Across the KE front, by contrast, the SSH gradient has been strongly intensified to the east of 150°E, in addition to the southward migration of the frontal axis and changes in its orientation as found in the SST field. The difference found in the decadal changes between the two fronts in the KOE region suggests that their changes could arise from different mechanisms.In association with the SSH gradient changes, the surface velocity fields has also changed between the two periods (Fig. 7). Consistent with the enhanced SSH gradient of the KE front and the change of its axis into more zonal orientation into the later period, the KE current has been intensified especially between 150°E and 170°E, and it flows eastward around 35°N in the laterperiod. Though not so significant as the KE current, an eastward current along the subarctic front13(Oyashio Extension) is also stronger in the later period between 150°E and 170°E. Furthermore, a southwestward Oyashio current along the Kuril Islands has also intensified slightly into the later period.c. Changes in subsurface frontal structuresThe aforementioned decadal-scale changes in the SSH fronts may be associated with some changes in dynamical fields that are likely to accompany the corresponding changes in subsurface thermal fields. In Fig. 8, we plot meridional sections of five-winter mean temperature (left) and salinity (right) simulated for the three periods, 1968-72, 1976-80 and 1984-88, with the corresponding anomaly fields as deviations from their 1950-2003 climatological mean fields. In each of the periods, the two fronts located at ~35°N and ~43°N exhibit their distinctive vertical structures in the subsurface temperature field, as found in the climatological mean field (Fig. 2). Comparing the top and bottom panels in the left column of Fig. 8, one can recognize southward migration of the subarctic and KE fronts into the later period also at subsurface levels, in a manner consistent with what is indicated in the SST and SSH gradient field. In association with their migration, pronounced temperature anomalies form below the surface along their axes in those two periods. The anomalies associated with the subarctic front are the strongest near the surface, while the strongest anomalies associated with the KE front are located 300~500 m below the surface. This difference reflects the corresponding difference in the vertical structure of the two fronts as mentioned in section 3.Interestingly, in the OFES simulation, decadal-scale cool anomalies first emerge within the near-surface subpolar gyre in the late 1970s (middle-left panel of Fig. 8) before the strongest cooling occurring in the early 1980s along the two fronts. In the late 1970s, warm anomalies still remain along the entire depth of the KE front, and the preceded cool anomalies in the subpolargyre seem to accompany no substantial salinity anomalies (middle-right panel). Nakamura et al.14。
