本文利用热带测雨卫星(TRMM)上搭载的测雨雷达(PR)十年的探测结果,对夏季中国南方对流降水和层云降水的气候特征进行了分析。研究结果表明:夏季中国南方层云降水频次较对流降水频次高出两倍以上,而对流降水强度至少是层云降水强度的4倍;就整个中国南方而言,这两种类型的降水对总降水量贡献相当。日变化分析表明夏季中国南方大部分地区的对流降水主要出现在午后,层云降水出现时间并不集中,但这两类降水的频次日变化均显示了明显的地域性特征;对降水廓线日变化的分析结果表明,对流降水和层云降水廓线的日变化主要表现在"雨顶"高度的日变化,即对流降水云的厚度有明显的日变化变化特征,不同地区的降水廓线存在明显的差异。降水率剖面分析结果显示了对流降水的"雨顶"高度日变化较层云降水剧烈,降水率的日变化则相反,且层云降水率的地域性特征更强。
The characteristics of summer convective and stratiform precipitation in southern China are investigated based on measurements by TRMM Precipitation Radar(PR)from 1998 to 2007.Results indicate that the frequency of stratiform precipitation is two times higher than that of convective precipitation,but the conditional rain rate of convective precipitation is nearly four times larger than that of stratiform precipitation,which result in the two types of precipitation have the same contribution to total rain.The distributions of both convective and stratiform precipitation suggest remarkable regionality.The frequency of convective precipitation reaches the peak in the afternoon over most of southern China,while the frequency of stratiform precipitation distributes mildly.The diurnal cycles of convective and stratiform precipitation profiles are mainly displayed in the variation of "storm top",namely,the variation of precipitation cloud depth.Moreover,the profiles of two types of precipitation over different regions are obviously distinct.The cross sections of two types of precipitation not only show that the variation of the "storm top" of convective precipitation is much sharper than that of stratiform precipitation,but also show the diurnal cycle of the conditional rain rate of stratiform precipitation is sharper than that of convective precipitation.The conditional rain rate of stratiform precipitation changes more significantly among different regions.