摘要
分别计算热量和水汽收支方程,得出1991年长江中下游梅雨期(5月18日至7月13日)降水区内面积平均的视热源Q_1和视水汽汇Q_2高度时间剖面图,由该图的垂直分布特征,可以看出梅雨期可分为三个降水时段,每个时段加热的强度和垂直分布形式互不相同,其中第三时段明显呈现典型对流性降水性质。其次对收支方程垂直积分,得出105—122°E,24—40°N区域第三时段内Q_1和Q_2高度-时间积分的水平分布图,两者水平分布形式比较一致,且与实际降水量分布较为吻合,说明加热场主要由凝结加热过程所致,同时也证实上述Q_1和Q_2的计算结果是可靠的。
The daily variations of area-averaged apparent heat source Q_1 and the apparent moisture sink Q_2 during Mei-Yu over the middle and lower valley of the Yangtze River have been estimated with the budget calculation method. Three precipitation periods are divided according to the vertical pattern, but the intensity and vertical profiles differ from each other and the third period is characterized by convective rain. In addition, integrating (1) and (2), the mean horizontal distribution of Q_1 and Q_2 for the third period is obtained. It is revealed that the horizontal distribution of the vertically integrated heat source coincides with that of moisture sink, and with the observed precipitation amount. This shows that the heating processes for Mei-Yu season result from condensation by precipitation and that the computations of Q_1 and Q_2 are reliable.
关键词
梅雨期
暴雨
降水
热量
水汽
The budget of heat and moisture, heavy rain during Mei-Yu, feedback effects
