ENSO与亚洲中低纬若干海气因子的遥相关及与华南降水的关系

AHE TELECONNECTION BETWEEN ENSO AND A FEW SEA-ATMOSPHERE FACTORS FOR ASIAN MID-LOW LATITUDES AND ITS RELATION TO THE SOUTH CHINA RAINFALL

摘要:

本文在统计近一百年左右华南八站降水与ENSO关系基础上,分别探讨了春末夏初亚洲中纬冷空气活动,南海高压及副高脊、盂加拉湾北部低系统和中南半岛季风与ENSO的遥相关,以及它们对华南3—6月降水的影响;台风活动,南海SST与ENSO遥相关及其对华南7—11月降水的影响。指出,El Nino年春夏东亚中纬冷空气活动偏弱,南海高度场偏低,孟加拉湾北部低系统和中南半岛西南季风较活跃。使El Nino年3—6月华南内陆降水偏少而沿海偏多。在ElNino年,南海SSTA有一个由负转正的过程,它使华南沿海在秋台偏少情况下,秋冬有时还有较大的降水甚至带来洪涝。

Abstract:

Based on statistics of rain records from 8 South China stations amd their association with ENSO for 100 years,the paper investigates into the teleconnection between ENSO and (l)cold air activities in East Asian midlatitudes in late spring and early summer,(2) South China Sea High and the subtropical high ridge,(3) lowpressure systems in the northern Bay of Bengal and (4) monsoon in the Indo china Peninsula; and in general,their influence on the rainfall in South China in March to June. The investigation also encompasses the impact of the teleconnection between the SST for the South China Sea and ENSO on the July-November rain-fall in South China. It is pointed out that the El Nino years are associated with weaker cold air activities in spring and summer in mid-latitude East Asia,lower geopotential heights in the South China Sea,more active low-pressure systems in the Bay of Bengal and southwest monsoon in the Indochina Peninsula. All of these account for less rain than usual in inland South China and more rain on its coast in the El Nino years. These years also see transitions in SST from negative to positive in the South China Sea,bringing relatively heavy rain,even floods,to the South China coast when there are fewer typhoons in the autumns.