华南春季强对流天气过程的动能收支——(二)辐散风和旋转风动能的收支和转换

KINETIC ENERGY BUDGETS OF AN INTENSE CONVECTION EVENT DURING SPRING OVER SOUTH CHINA, PART——II: BUDGETS AND CONVERSION OF DIVERGENT AND ROTATIONAL KINETIC ENERGY

在第(一)部分的基础上,进一步讨论辐散风动能和旋转风动能的收支以及这两种动能之间的转换过程。结果表明,尽管辐散风动能在总动能中所占比重很小,但它的变化与强对流天气过程的发生发展有着更为密切的关系。计算结果表明,在辐散风动能与旋转风动能的转换函数{K_D,K_R)中,B项(代表垂直运动与旋转风动能的垂直变化的耦合)是最大的转换项;在强对流区,反映涡管伸缩机制的A项也是一个很重要的转换项。就区域时间平均而言,有旋转风动能向辐散风动能(K_R→K_D)转换。

Budgets of divergent and rotational kinetic energy of an intense convection event occurred on March 1st 1983 have been investigated in this part with operational observation data. It has been shown by the results that although the divergent kinetic energy is a small intergant in the total kinetic energy its variations are more closely related to the occurence and the development of the intense convection. Among the three integrants of the energy conversion function {K.D,KR} between KD(divergent kinetic energy) and KR(rotational kinetic energy), term B( ) is the major contributor and term A( ) is a close second in importance. For the time-area mean, the energy conversion {KD,KR} is negative indicating energy conversion from KR to KD.