| 亚洲—太平洋地区冬季海平面气压异常偶极模与我国冬季气候异常的关系 |
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| 引用本文： | 赵巧莲,李崇银.亚洲—太平洋地区冬季海平面气压异常偶极模与我国冬季气候异常的关系[J].气候与环境研究,2012,17(1):1-12. |
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| 作者姓名： | 赵巧莲 李崇银 |
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| 作者单位： | 1. 解放军理工大学气象学院,南京,211101
2. 解放军理工大学气象学院,南京211101;中国科学院大气物理研究所大气科学和地球流体国家重点实验室,北京100029 |
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| 基金项目： | 国家重点基础研究发展计划项目2007CB411805 |
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| 摘 要： | 利用全球月平均海平面气压资料和各标准等压面的位势场、风场，以及我国160站的降水和温度资料，研究了亚洲—太平洋（20°N~70°N，40°E~120°W）地区（简称亚太地区）冬季（12~2月）海平面气压异常偶极型振荡（偶极模）的时间变化特征，以及该异常偶极模与我国冬季气候异常的关系。结果表明：近半个世纪以来，亚太地区冬季海平面气压场异常以经向型（ME）偶极模负异常和纬向型（ZO）偶极模正异常为主，其中又以ZO正异常发生的频数较高。对应ME模，其各空间层的高度场异常形势和高度场与MEI（经向型指数）的相关系数分布形势十分类似；对应ZO模则主要表现为与阿留申地区高相关中心的一致性特征，说明阿留申低压的变化对其起着重要作用。ME模与我国冬季东部的降水异常和气温异常关系密切，ZO模仅对东北地区的降水异常有影响，因为ZO模的异常对我国上空大气环流异常的影响相对较小；这一结果同我们传统上在冬季比较关注纬向气压差的变化（即ZO模）有些相左，提示我们在冬季更要关注ME模的情况。大气环流形势的分析表明， MEI正异常时，即西伯利亚—蒙古冷高压的北半部气压异常偏高，副热带西北太平洋地区气压偏低时，利于东亚大槽的加深加强，东亚冬季风因而也会偏强；但是由于此时我国东部主要为下沉气流控制，暖湿气流难于源源不断地输送到我国境内，从而造成此时冬季我国东部尤其是长江中下游地区降水偏少。反之，当MEI负位相时，大气环流异常利于造成我国东部大范围的冬季降水。
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| 关 键 词： | 亚太地区 冬季气压偶极模（偶极型振荡） 中国冬季气候 |
Dipole Mode of the Sea Level Pressure Anomalies in Asia-Pacific Region and the Relation to Winter Climate Anomaly in China |
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| ZHAO Qiaolian and LI Chongyin.Dipole Mode of the Sea Level Pressure Anomalies in Asia-Pacific Region and the Relation to Winter Climate Anomaly in China[J].Climatic and Environmental Research,2012,17(1):1-12. |
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| Authors: | ZHAO Qiaolian and LI Chongyin |
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| Institution: | 1,2 1 Institute of Meteorology,PLA University of Science and Technology,Nanjing 211101 2 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029 |
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| Abstract: | Using the global monthly mean sea level pressure data,geopotential height,and wind field data as well as the rainfall and temperature data from 160 stations in China,the authors further analyze the temporal variation characters of dipole modes and the relationship between dipole modes and winter climate anomalies in China after studied spatial structure of the sea level pressure anomaly dipole oscillations(dipole modes) over the Asia-Pacific region(20°N-70°N,40°E-120°W) in winter(December to February).The results show that:During the past half century,the winter sea level pressure anomalies(SLPA) over the Asia-Pacific region mainly character with a negative anomalies of meridional-type dipole mode(ME) and a positive anomalies of zonal-type dipole mode(ZO),while the later one occurrs in a higher frequency.Corresponding to ME-mode,there are similarities between geopotential height anomalies and the correlation coefficient distribution of height field and the MEI;on the other side,it takes a consistency feature with a high correlation center over the Aleutian region corresponding to ZO-mode,which manifest that the variation of Aleutian Low plays an important role for them.The ME-mode is close related to precipitation anomalies and temperature anomalies in the eastern of China in winter.However,because of the relatively weak influence of the ZO-mode on the atmospheric circulation anomalies over East Asia,the ZO-mode only affected the rainfall anomalies in Northeast China.This result challenges the traditional concerning about the zonal pressure difference(mainly represent ZO-mode) in winter and means we should pay more attention to the ME-mode.After analyzing of the atmospheric circulation,the authors found that when the MEI is positive anomaly,which means that the pressure field shows a positive anomaly over the northern half of Siberia-Mongolia high and a negative anomaly over subtropical Northwestern Pacific region,this is helpful to enhance and deepen of the East Asia trough,then the East Asian winter monsoon will be stronger,too.However,at this time,the Eastern China region is mainly controlled by sinking air and the warm humid air can not continuously be transported to there,which results in the lack of rainfall over there,especially over the Yangtze River basin.On the contrary,when it is in MEI negative phase,the atmospheric circulation anomaly is conducive to result in a wide range of precipitation in eastern China. |
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| Keywords: | Asia-Pacific region winter dipole modes (dipole oscillations) of pressure winter climate of China |
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