云南暴雨涡散场动能转换函数的动态分析

THE DYNAMICAL ANALYSES FOR THE CHARACTERISTICS OF DIVERGENT AND ROTATIONAL COMPONENTS OF KINETIC ENERGY FOR HEAVY RAIN IN YUNNAN

关键词:  动能转换  涡散场  函数  暴雨

Key words:  Kinetic energy conversion  Divergent and rotational components  Function  Heavy rain

摘要:

对1996年云南主汛期(6－8月)逐日散度风动能和旋转风动能之间的转换函数C(KD,KR)特征进行深入研究,同时分析了C(KD,KR)各项Af、Az、B、C在动能转换函数中所起的作用。研究结果表明,对流层内C(KD,KR)>0,同时对流层低层的C(KD,KR)>中高层的C(KD,KR)之和．极易出现暴雨过程;Af项在整个动能转换中起主要作用,71%的Af与C(KD,KR)具有相同的符号,Az项和B项在动能转换中起振荡作用,Az＋B控制着29%的动能转换方向。

Abstract:

This paper further studies the kinetic energy conversion function in the flood season(June toAugust) in 1996,and analyses effects on C(KD,KR) by terms Af, Az, B, C. The results showthat heavy rain processes will occur if C(KD,KR)>0 and C(KD,KR) in the lower torpephericlayers is larger than the sum of C(KD,KR) in the middle and high tropepheric layers. Term Afacts the main role in the kinetic energy conversion. 71% of signs of term Az are the same as that of C(KD,KR). Terms Az and B act to vibrate in the kinestic energy conversion. 29% of signs of the sum of terms Az and B are the same as C(KD,KR).