PJ遥相关型对长江中下游夏季降水影响的不对称性  

Asymmetric effect of Pacific-Japan teleconnection pattern on summer precipitation in middle and lower reaches of Yangtze River

作　　者：陶丽[1,2] 于国强 王学兵 TAO Li;YU Guoqiang;WANG Xuebing(Key Laboratory of Meteorological Disaster,Ministry of Education(KLME),Nanjing University of Information Science&Technology,Nanjing 210044,China;School of Atmospheric Sciences,Nanjing University of Information Science&Technology,Nanjing 210044,China;Zhongning County Meteorological Bureau,Zhongwei 751200,China)

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室,江苏南京210044 [2]南京信息工程大学大气科学学院,江苏南京210044 [3]中宁县气象局,宁夏中卫751200

出　　处：《大气科学学报》2020年第2期299-309,共11页Transactions of Atmospheric Sciences

基　　金：国家重点研发计划项目(2016YFA0600402);国家自然科学基金资助项目(41630423,41375098);江苏高校优势学科建设工程资助项目(PAPD)。

摘　　要：利用1979-2015年海洋和大气再分析资料,基于夏季太平洋-日本遥相关型(PJ)指数,讨论了PJ指数在极端正负年份长江中下游降水位置和强度异常的不对称响应及其可能原因。结果表明:在PJ负位相年(对应El Niňo次年),长江中下游降水显著偏多,中心分别位于江淮流域和日本南部;而在PJ正位相年(对应La Niňa次年),长江中下游降水减少却不明显。研究发现:在PJ负位相年,中东太平洋、印度洋、南海地区海温明显偏暖,菲律宾海上空有异常反气旋响应,长江中下游地区有异常气旋响应;而在PJ正位相年则反之。在PJ负(正)位相年,菲律宾海异常反气旋(气旋)和长江中下游地区异常气旋(反气旋)明显偏强(偏弱),由此导致长江中下游降水位置和强度异常存在不对称响应。基于大气环流模式ECHAM4.8的敏感性数值试验结果表明,即使印度洋海温偏暖与偏冷程度相当,但由偏暖印度洋海温激发的菲律宾海异常反气旋也明显偏强,从而造成长江中下游地区降水偏多程度大于偏少程度。由此印证的事实是:El Niňo次年(PJ负位相年)长江中下游夏季降水偏多的预测技巧高于La Niňa次年夏季降水偏少的预测技巧。Based on various oceanographic and atmospheric reanalysis data from 1979 to 2015,this paper analyzed anomalous distribution characteristics of summer rainfall in the middle and lower reaches of the Yangtze River during different phase years of PJ( Pacific-Japan) teleconnection pattern and discussed possible causes of asymmetric precipitation changes.Result shows that the asymmetry of anomalous precipitation distribution includes asymmetric position and intensity.In the negative PJ phase year( corresponding to the next year of El Ni1 o),precipitation in the middle and lower reaches of the Yangtze River increases significantly,with two maximum precipitation centers located in the Changjiang-Huaihe River Basin and southern Japan. In the positive PJ phase year( corresponding to the next year of La Ni1 a),precipitation decrease is not obvious in the middle and lower reaches of the Yangtze River. The previously winter SST anomalies closely relate to PJ teleconnection pattern are similar to distribution characteristics of ENSO.It shows that during the negative PJ phase year,positive SST anomalies in the eastern and central Pacific,Indian Ocean and South China Sea are stronger than negative SST anomalies in the positive PJ phase year.In the negative PJ phase year,warmer SST in Indian Ocean excites an abnormal anticyclone over the Philippine Sea and an abnormal cyclone over the middle and lower reaches of the Yangtze River.It is vice versa in the positive PJ phase year.In the negative PJ phase year,the abnormal anticyclone over the Philippine Sea and the abnormal cyclone over the middle and lower reaches of the Yangtze River are stronger than the abnormal cyclone over the Philippine Sea and the abnormal anticyclone over the middle and lower reaches of the Yangtze River in the positive PJ phase year.It leads to the asymmetric response of precipitation position and intensity anomalies in the middle and lower reaches of the Yangtze River.Based on the general circulation model ECHAM4. 8,the sensitivity numerical simulation re

关 键 词：PJ遥相关型 夏季降水 不对称性 

分 类 号：P461[天文地球—大气科学及气象学]