La Nia年冬季亚洲中高纬环流与我国南方降雪异常关系  

Relationship between Asian Circulation in the Middle-High Latitude and Snowfall over South China during La Nia Events

作　　者：张庆云[1] 宣守丽[2] 彭京备[2] 

机构地区：[1]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室,北京100029 [2]中国科学院大气物理研究所灾害性气候研究与预测中心

出　　处：《气候与环境研究》2008年第4期385-394,共10页Climatic and Environmental Research

基　　金：中国科学院大气物理研究所创新基金领域前沿重点项目IAP07120;中国科学院知识创新工程重要方向项目KZCX3-SW-226

摘　　要：2007/2008年冬季,赤道中东太平洋形成了一次中等强度的La Ni~↑na事件。本文根据NCAR/NCEP再分析资料,探讨La Nina气候背景下亚洲中高纬大气环流及南亚上空南支槽强度与我国南方（25～35°N,110～125°E）多雪、少雪以及2008年1月我国南方大范围低温雨雪冰冻灾害的关系。分析指出,La Ni~↑na气候背景下,500 hPa高度场亚洲高纬位势高度偏高易出现阻塞型,当乌拉尔山阻塞高压强度、位置比鄂霍次克阻塞高压偏强、偏北时,入侵我国南方的偏北气流主要来自乌拉尔山地区,南方偏冷（距平达-4.0℃）多雪;当鄂霍次克阻塞高压强度、位置比乌拉尔山阻塞高压偏强、偏北,入侵我国南方的偏北气流主要来自鄂霍次克海地区,南方偏暖（距平达1.0℃）少雪。2008年1月500 hPa高度上亚洲高纬乌拉尔山阻高偏北、强度偏强（正距平中心值达120 gpm）,入侵我国南方的2支偏北气流都来自乌拉尔山地区,南方出现了低温（温度距平达-4.0℃）雨雪冰冻天气;分析指出,200 hPa高度场南亚地区南支槽的强弱对我国南方降雪多寡有重要影响。The moderate-strong La Ni~↑na was throughout in boreal winter 2007-2008 year,and the anomalous snowfall and extreme low temperature occurred in South China during January 2008.The Asian Circulation in middle-high latitude and association with the aspect of snowfall in South China during La Ni~↑na events were studied based on NCAR/NCEP reanalyzed dataset.It had been found that there was a blocking pattern in Asian Circulation of middle-high latitude at 500 hPa during La Ni~↑na events.When the intensity of blocking pattern over Ural Mountains was stronger than over Okhotsk Sea in January during La Ni~↑na years,the temperature in South China was lower than normal and there was association with heavy snowfall due to the northerly wind in South China was related with the circulation in Ural Mountains.When the intensity of blocking pattern over Okhotsk Sea was stronger than over Ural Mountain in January during La Ni~↑na years,the temperature in South China was above normal and association with a light snowfall due to the northerly wind in South China was connected with the circulation in Okhotsk Sea.In January 2008,the intensity of blocking pattern over Ural Mountain looks more strengthened（positive anomalous 120 gpm）.There were two branchs northerly wind in South China,and both of them were associated with the circulation from Ural Mountain which resulted in the colder air temperature in South China.The intensity of southern branch jet stream over Southern Asia at 200 hPa and its association with the snowfall in South China during La Ni~↑na events were also discussied.

关 键 词：LA Ni~↑na事件南方多雪 阻塞高压 西风急流 

分 类 号：P461[天文地球—大气科学及气象学]