初夏印度高压的季节转换及其与北半球环流和我国夏季降水的关系

本文以初夏印度高压撤离印度地区的早迟,来反映冬夏季节转换的早晚,并讨论这种季节转换的突变现象与北半球环流和我国夏季降水的关系。分析表明,初夏印度高压季节转换的早、晚,反映在印度地区500hPa高度距平符号是完全相反的,这种距平场的扰动,以波动形式沿一定的通道向东亚中高纬度地区传播,然后通过极区传向西半球。当印度高压季节转换早时,夏季西太平洋副高易北上,东亚中高纬度距平场往往出现东高西低的环流形势,相应我国汛期降水偏多,反之亦然。同时,5月印度地区高度场变化对我国长江中下游入梅日期也有一定的指示意义。在近几年的实际应用中,这种正相关关系保持着较好的稳定性。

The seasonal transition of Indian high in early summer and its relation with general circulation in Northern Hemisphere and summer precipitation in China

The paper discusses the relation between the seasonal transition from winter to summer indicated with evacuation of high from Indian area and general circulation in Northern Hemisphere and summer precipitation in China. It shows that during the early (late) year of seasonal transition from winter to summer negative (positive) anomaly of 500hPa height field in Indian area is dominant, West Pacific subtropic high is to the north (south), summer rainfall is plentiful (less). The anomaly disturbance of 500hPa height field in Indian area propogates as a wave along a passage through the extratropics in East Asia and polar to Western Hemisphere.