北半球夏季对流性降水特征及其与厄尔尼诺的关系

摘要

利用2003-2014年6-8月CMORPH 3 h卫星降水资料,统计分析北半球夏季对流性降水的空间分布,发生的概率,日变化以及其对厄尔尼诺事件的响应等特征.结果表明,对流性降水在6-8月除了发生于热带辐合带等海域外,北美中部,东南亚和热带非洲等陆地区域更为突出.其降水强度发生在10～11 mm·h-1之间的概率最大,极端强对流性降水发生在陆地上的概率大于海洋.对流性降水的日变化表现为,陆地上于傍晚(18-20时)和夜间(22-01时)有两个峰值;海洋上对流性降水多出现于夜间到早晨这段时间,而下午出现的概率最低.厄尔尼诺发展年,海洋上对流性降水增强,而陆地上发生的概率总体偏小,衰减年则相反;中国东部,尤其是长江以南地区的非对流性降水在厄尔尼诺发展年,多于正常年,与对流性降水的响应不一致.%Based on 3-hour CMORPH satellite precipitation data during 2003-2014,the convective precipitation characteristics of spatial distribution,occurrence probability,diurnal variation and its response to the E1 Ni(n)o were analysed.Results show that the convective precipitation is mainly distributed on the ocean near ITCZ,central North America,Southeast Asia and tropical Africa,etc.The convective precipitation occurrence probability is the largest between the intensity of 10-11 mm·h-1,and the probability of extreme strong convective precipitation of land is greater than that of ocean.The diurnal variation of convective precipitation is presented with two peaks on land,in the evening(18-20 LST) and midnight(22-01 LST).And its occurrence probability is lager between midnight and morning on ocean.The convective precipitation increases on ocean and decreases on land in developing years of El Ni(n)o,while the weakening years are opposite.Nonconvective precipitation on the eastern part of China is more during the El Ni(n)o years than that during normal years,and the results are different form the response of the convective precipitation.