“96.8”暴雨过程的尺度分离动能方程的诊断

DIAGNOSIS OF “96 8”TORRENTIAL RAIN WITH THE SCALE SEPERATION KINETIC ENERGY EQUATION

用尺度分离的动能平衡方程，对１９９６年８月３～５日华北地区台风暴雨过程雨区内的动能制造和转换进行诊断．结果表明：动能在暴雨发展过程逐渐减小，动能转换项也是逐渐减小的．暴雨发生前，尺度相互作用制造项ＧＫＭＳ起最重要的作用，大尺度动能制造项次之，中尺度动能制造项消耗少量的动能；暴雨发生时，尺度相互作用和天气尺度运动仍制造动能，只是比发生前明显减少，中尺度运动由消耗动能转变为制造动能，动能转换主要来源于低层且数值明显减少；暴雨发生后，动能制造项数值仍为正，此时天气尺度动能制造最重要，但数值比前两阶段小，动能的转换主要出现于高层．可见，此次暴雨过程总动能的制造项一直为正，主要出现于高层，只是其制造量逐渐减小；动能转换是从低层向高层进行的，水平转换项起主要作用，是一种尺度减小的动能转换过程．

Using the scale seperation kinetic energy equation,the generations and transformations of kinetic energy during the torrential rain process of North China in August 1996 are calculated. The results show that during the developing process of “96 8”torrential rain, the kinetic energy was gradually decreased, and so was the kinetic energy transformation. Before the torrential rain, GKMS played the most important role, and GKS the second, whereas GKM dissipated a few energy. During the torrential rain, GKMS produced the energy, but less than before apparently, GKM also produced energy, the energy conversions mainly came from low level. After the torrential rain, the producers of the kinetic energy were still greater than zero, at that time GKS was the most important one and the amount was less than the first two periods, and the conversions appeared over upper level. It is shown that during the torrential rain process the total producers of kinetic energy were always positive, they mainly appeared over high level, but the amount of kinetic energy was decreased gradually. The conversion of kinetic energy was from low level to high level, the horizontal term played the main role, and it was an energy transformation process of scale reduction.