1991年和1994年南京夏季降水异常和副热带东北太平洋海温异常的联系及成因
投稿时间: 2018-03-29  最后修改时间: 2018-04-10  点此下载全文
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作者单位E-mail
胡杨 南京信息工程大学 气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心 huyangzai@126.com 
金大超 南京信息工程大学 气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心 jindc@nuist.edu.cn 
王易 江苏省气象台  
米热阿衣·台来提 南京信息工程大学 气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心  
基金项目:南京信息工程大学大学生实践创新训练计划项目(201710300044Z)
中文摘要:利用1979-2015年共37年的观测降水资料、海表温度资料及再分析资料,研究了南京夏季降水的时间变化规律,发现南京夏季降水具有明显的年际和年代际变化,总体呈增多的趋势。其中1991年南京夏季降水为极端正异常年份,距平为343.92mm;1994年南京夏季降水为负异常年份,距平为-273.78mm。南京夏季降水和副热带东北太平洋(美国加利福尼亚地区西海岸)海温异常存在显著的负相关关系,1991年副热带东北太平洋海温负异常,1994年副热带东北太平洋海温无显著异常。1991年副热带东北太平洋海温负异常,引起该地区上空低层辐散、高层辐合,热带中东太平洋上空低层辐合、高层辐散,这样的环流异常引起中东太平洋上空存在异常上升运动,该上升运动则可通过纬向垂直环流引起菲律宾附近产生下沉运动并抑制了该地区的对流活动,激发了负位相的EAP/PJ型遥相关波列,引起包括南京在内的长江流域降水正异常;同时,水汽由菲律宾地区向南京地区输送并辐合,有利于南京地区1991年夏季降水偏多。1994年副热带东北太平洋海温无显著异常,菲律宾附近对流活动活跃,激发了正异常的EAP/PJ型遥相关,同时水汽由黑潮延伸区经日本列岛向西输送,南京地区为水汽辐散区域,使得1994年南京夏季降水负异常。
中文关键词:夏季 降水异常 南京 海表温度异常 副热带东北太平洋
 
Relationship and analysis of Nanjing anomalous summer precipitation and subtropical northeast Pacific SST anomalous in 1991 and 1994
Abstract:Based on the observed precipitation data, sea surface temperature data and reanalysis data from 1979 to 2015, the temporal features of Nanjing summer precipitation are analyzed. The results indicate that the precipitation has obvious interannual and interdecadal variations, with an overall increasing trend. In 1991, the summer precipitation in Nanjing was an extremely positive anomaly, with the anomaly of 343.92mm, while precipitation in 1994 was a negative anomaly, with the anomaly of -273.78mm. There is a significant negative correlation between the summer precipitation in Nanjing and the sea surface temperature anomalous(SSTA) in the subtropical northeast Pacific (the west coast of the California in the United States). The SSTA in subtropical northeast Pacific was negative in 1991, and was no significant anomaly in 1994. This SSTA in 1991 caused low level divergence and high convergence over subtropical northeast Pacific, and low level convergence and high level divergence over the tropical Middle East Pacific. This circulation caused that the vertical velocity in Middle East Pacific Ocean was upward, which can cause Philippines area in downward motion and inhibited the convective activities in the region by vertical circulation in latitude, stimulating EAP/PJ in negative phase, causing the Yangtze River basin precipitation anomaly, including Nanjing. At the same time, the water vapor was transported from Philippines to Nanjing, which was propitious to more precipitation in the summer in Nanjing area. In 1994, the SSTA was consistent with climate, with active convective in Philippines, which stimulated the positive anomaly of EAP/PJ teleconnection, and water vapor was transported westward from the extended area of the Kuroshio through the Japanese islands, and the Nanjing region was in a water vapor divergence area, which made the summer precipitation in Nanjing of 1994 a negative anomaly.
keywords:Summer  anomalous precipitation  Nanjing  sea surface temperature anomalies  subtropical northeast Pacific
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