| 近40年来东亚冬季风的年代际时空变化趋势 |
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| 引用本文： | 施晓晖,徐祥德,谢立安.近40年来东亚冬季风的年代际时空变化趋势[J].大气科学,2007,31(4):747-756. |
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| 作者姓名： | 施晓晖 徐祥德 谢立安 |
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| 作者单位： | 1.中国气象科学研究院灾害天气国家重点实验室,北京,100081 |
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| 基金项目： | 国家自然科学基金资助项目90502003，科研院所社会公益研究专项2005DIB3J057，国家重点基础研究发展规划项目2003CB716806 |
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| 摘 要： | 利用经验正交函数－奇异值分解（EOF－SVD）综合分析方法和1961～2000年NCEP/NCAR月平均再分析资料对近40年来东亚冬季风和冬季表面气温的年代际变化特征及其相关关系进行了分析。研究结果表明, EOF得到的冬季海平面气压场主成分空间结构（第一特征向量）及其时间系数可以较好地反映出东亚冬季风的变化, 而且可以同时得到东亚冬季风强度和南扩程度的变化, 具有一定的优越性。通过对冬季海平面气压和表面气温年代际分量的EOF－SVD综合分析, 发现了东亚冬季风强度减弱、南扩加强的年代际变化趋势, 冬季表面气温则表现出中高纬地区海陆热力差异减弱、低纬地区海陆热力差异加强的年代际变化特征, 两者之间存在很好的对应关系。另外, 大陆冬季表面气温与海平面气压的年代际对应关系比海洋的更加显著, 表明对温室效应的区域气候响应与东亚冬季风的年代际变化之间可能存在较为密切的联系。
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| 关 键 词： | 东亚冬季风 年代际变化 EOF-SVD综合分析 |
| 文章编号： | 1006-9895（2007）04-0747-10 |
| 修稿时间： | 2006-02-152006-07-27 |
Interdecadal Spatial-Temporal Change Trend of East Asian Winter Monsoon in the Last 40 Years |
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| SHI Xiao-Hui,XU Xiang-De and XIE Li-An.Interdecadal Spatial-Temporal Change Trend of East Asian Winter Monsoon in the Last 40 Years[J].Chinese Journal of Atmospheric Sciences,2007,31(4):747-756. |
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| Authors: | SHI Xiao-Hui XU Xiang-De and XIE Li-An |
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| Institution: | 1 State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081 ;2 DepartmentofMarine, Earthand Atmospheric Sciences, NorthCarolina State University, Raleigh NC27695-8208 |
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| Abstract: | The spatial-temporal characteristics of the interdecadal change(IC) of East Asian winter monsoon(EAWM),represented by sea level pressure(SLP),and surface air temperature(SAT) in winter during the period of 1961-2000 and their relationship are studied based on NCEP/NCAR reanalysis data and using some statistic methods,such as running mean,correlation analysis and empirical orthogonal function-singular value decomposition(EOF-SVD) compositive analysis.The basic clue of EOF-SVD compositive analysis is(1) decomposing SLP and SAT in winter by EOF respectively to gain their principal spatial structure,i.e.,the first eigenvectors,and temporal change trends,denoted by the corresponding time coefficients(TC),as well as the relationship of their spatial-temporal changes;(2) using SVD of SLP and SAT in winter to investigate their spatial remote correlations if the close relation is found in step 1.Results suggest that using the EOF of SLP to investigate the variety of EAWM is reasonable and superior to EAWM index defined by regional mean,because it can attain the spatial structure of SLP,which simultaneously includes the information of the intensity and southward extending of EAWM.According to the EOF results,it is found that on interannual scale,EAWM exhibits an overall weakening trend in the past 40 years.By means of EOF-SVD compositive analysis on interdecadal scale,the results show that the first eigenvector of interdecadal component(FEIC) of SLP in winter displays a spatial structure with "negative in north and positive in south" over East Asia and positive anomalies over the sea.A turning from negative to positive happens to the TC of the first eigenvector in the late 1970s,reflecting the interdecadal weakening of intensity and southward extending of EAWM.The FEIC of SAT in winter exhibits a spatial distribution with distinctive warming over middle-high latitude land and little change over low latitude land and sea.A turning from negative to positive for the TC also occurs in the early 1980s,suggesting an interdecadal decreasing trend of sea-land thermal difference(SLTD) in middle-high latitudes and an interdecadal increasing trend of SLTD in low latitudes.The spatial-temporal changes of the above two meteorological elements are in accordance,indicating the close correlation between the interdecadal spatial-temporal changes of EAWM and SAT in winter.The results of SVD indicate that the interdecadal corresponding relationship between SLP and SAT in winter over land is more significant than that over sea,suggesting the IC of EAWM may be associated with the regional response of the climate in East Asia to the heterogeneous spatial structure of global warming. |
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| Keywords: | East Asian winter monsoon interdecadal change EOF-SVD compositive analysis |
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