南海夏季风建立前后的大气能量收支

THE ENERGY BUDGETS BEFORE AND AFTER THE ESTABLISHMENT OF THE SUMMER MONSOON OVER THE SOUTH CHINA SEA

摘要:

本文用总动能、总有效位能、扰动动能和扰动有效位能四个收支方程计算了1980年4-6月南海南部(0-15°N,100-120°E)夏季风建立前(4月1日-5月9日)和夏季风建立后(5月18日-6月25日)各时段的大气能量收支,并对其结果进行了分析讨论,发现:(1)总动能主要是在制造项G(K)(汇)与耗散项D(K)(源)间达到平衡,夏季风建立后源汇强度值都增大了40%左右。(2)非绝热加热所直接制造的有效位能并不重要,高层总有效位能的水平通量辐合、中低层与总动能间的转换和由于参考气压的变化而引起总有效位能的增减对于总有效位能的收支作用较大,其作用在夏季风建立前后也明显不同。(3)扰动动能同总动能一样主要在制造项G(K)(汇)与耗散项D(K)(源)间平衡。夏季风建立后源汇强度增强。(4)扰动有效位能主要由非绝热加热制造,夏季风建立后制造量增大了16倍多。夏季风建立前,扰动有效位能主要因参考气压的改变而减少;夏季风建立后,扰动有效位能主要被转换为扰动动能和平均有效位能。

Abstract:

The kinetic energy and the available potential energy budgets for large scale disturbances and general flow of the tropical circulation were calculated over the South China Sea for April-June, 1980, when kinetic energy budget of general flow was characterized by an energy source, the so-called dissipation term, which compensated for the cross. iso baric destruction, and the cross-contour generation,the energy sink. They constitued a balance of eddy kinetic energy. Available potential energy balance in general flow was mainly determined by the coversion term and the term related to changes in the reference pressure. For eddy available potential energy, however, the diabatic heating was much significant, and the exchanges among Ke,As and Ae,the horizontal flux divergence, and the changes in the reference pressure, were all important. Again, resultant energy budget contents before the summer monsoon onset was found to be much different from that after the summer monsoon onset.