华南一次暴雨过程的中尺度结构

利用合成分析方法检验了一次华南暴雨的三维气象要素场的分布。发现一个具有微冷锋特徵的辐合线是造成这次暴雨的主要中系统。在低层,暴雨区的后部存在着弱下沉气流,并导致了一个相应的低层冷区和地面弱流出辐散气流。中、高层是一中尺度暖区。暴雨区介于天气尺度高、低空急流之间,并且有向着最大上升区移动的趋势。      

华南前汛期暖区暴雨流场结构的特征

采用国家气象中心整编的１９５１－１９９０年中国１６０测站的月平均温度和月总降水量资料以及北半球５００ｈＰａ月平均高度场和海平面气压场资料，讨论近４０年来中国气候型转变与北半球大气环流特征的变化关系。     

江淮切变线—梅雨锋次级环流的诊断研究

本文利用推广的Sawyer－Eliassen锋面次组环流方程对一次江淮切变线──梅雨锋系统的次级环流进行了诊断研究，讨论了它的特征以及形成。发现各强迫项在不同地理位置所起的作用是不同的，所形成的环流特征也不同。高低空急流及凝结加热对次级环流的形成和加强起着重要作用。     

西南低空急流的能量学分析

本文分析了梅雨期内三次西南低空急流的实例,结果表明,散度风动能产生和积云对流效应是低中空急流的动能来源,而影响散度风动能产生的主要物理因子是潜热加热,温度平流以及ω方程中散度项的作用。     

MOIST POTENTIAL VORTICITY DIAGNOSIS OF A MEIYU FRONTAL HEAVY RAIN PROCESS SIMULATION DURING SUMMER,1991

In this paper,the heavy rain process from June 30 to July 2,1991,has been simulated by MM4.and three-dimensional moist potential vorticity distribution of the simulation results has beencalculated.It is shown that moist potential vorticity is an important physical variable to reveal heavyrain structure and dynamic mechanisms.Negative moist potential vorticity corresponds to the Meiyufront-wind shear line system and the negative center corresponds to the heavy rain center.Negativemoist potential vorticity mainly attributes to the effects of meridional baroclinic term and convectiveunstable term.The former is favourable to the maintenance of zonal precipitation and the latter is themechanism of the heavy rain center propagating along the rain belt.The heavy rain is contributed bythe cooperative effects of conditional convective instability,baroclinic instability and upper air inertialinstability.