暴雨过程低空急流区域的动能平衡分析  

Energy Transformation in Two Lower Tropospheric Jets Accompaning Storm Rainfalls

作　　者：辜旭赞 方慈安 吴宝俊 

机构地区：[1]湖南省气象台 [2]中国气象科学院

出　　处：《气象》1996年第9期3-9,共7页Meteorological Monthly

摘　　要：用有限区域细网格客观分析系统，诊断和分析了１９９３年、１９９４年的两次伴随着暴雨过程的低空急流选定区域内的动能平衡。发现，虽然计算区域内平均总动能较大，且有其一定的变化，但计算出的各时次总动能产生值比其变率却一般要大两个量级以上，表明“波动”间，即“网格（大尺度）－次网格（小尺度）”运动之间的相互作用相当重要。求两次过程的平均则分别为２００、－２０６Ｗ·ｍ－２。表明前次过程平均为动能源区，具有“大尺度—小尺度（暴雨）”方向转换（耗散）动能的直接环流特征；后次过程平均为动能汇区，具有“小尺度—大尺度”方向转换（反馈）动能的间接环流特征，即存在一个所谓“负粘滞”问题。Kinetic energy budgets were prepared for lower tropospheric jet stream accompaning storm rainfalls of two courses in 1993 and 1994,with the use of analyses from a limited area fine mesh model (100×100km 2,ten layers) as well as objective analysis system.It shows that the generation rate of kinetic energy ( K ) by pressure forces is always two three orders bigger than change rate of K for every time.But the average generation rate as 200 206W/m 2 respectively,and the former was a source of kinetic energy,characterized by a large scale direct solenoidal circulation,the latter was a sink for subgrid to grid scale energy transfer,done by a indirect solenoidal circulation.So the kinetic energy changes of the small (subgrid ) scale flow (lead by storm motions) paralleled those of the large scale flow.This indicates a need for considering the apparent phenomenon of negative viscosity in mesoscale numerical atmospheric modeling for prediction of storm rainfalls.

关 键 词：动能平衡 暴雨 细网格模式 低空气流区 

分 类 号：P458.121.1[天文地球—大气科学及气象学]