梅雨锋动力锋生方程组及其应用

DYNAMIC FRONTOGENETICAL EQUATIONS OF MEIYU FRINT AND ITS APPLICATION

利用湿静力温度Ｔ＿σ作为参数，导出梅雨锋锋生的方程组，并用该方程组计算了１９９１年江淮梅雨锋强降水的个例。结果表明：该方程组可分析梅雨锋的动力锋生；在梅雨锋中存在近似垂直分布的对称的横向次级环流，环流中于冷侧的横向穿锋环流可建立湿状态的稳定性；非地转变形项对梅雨锋锋生（消）起主导作用，同时次级环流的上升运动与锋生有正反馈关系，另外，梅雨锋中Ｔ＿σ水平锋生对未来６小时降水具有一定的指示意义。

Using T_σ as frontogenetical parameter,the frontogenetical equations which can beused in meiyu front are derived. Because horizontal temperature gradient is very weak,and the moist gradient is very strong in meiyu front,classical dynamical frontogeneticalequations can not be used for diagnosis。Some cases of strong precipitation from meiyu front over Jiang-Huai valley in 1991are calculated.The results indicate that meiyu front dynamical frontogenetic equationscan be applied in these cases。There exist cross front secondary circulations in meiyufront,and the circulations is nearly vertical.The cross front circulation from dry andcold regime can establish moist static stability.The frontogenetical(frontolytical)iscaused mostly from ageostrophic metamorphonesis term,and it has a positive feedbackrelation with ascending motion of frontogenesis.The horizontal frontogenesis of T_σinmeiyu front has well indicating action for future six hours precipitation。