Dynamical and Thermal Problems in Vortex Development and Movement.Part I:A PV-Q View  

作　　者：郑永骏 吴国雄 刘屹岷 

机构地区：[1]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences [2]Graduate University of the Chinese Academy of Sciences

出　　处：《Acta meteorologica Sinica》2013年第1期1-14,共14页

基　　金：Supported by the National Basic Research and Development(973)Program of China(2012CB417203 and 2010CB950403);National Natural Science Foundation of China(40875034 and 40925015)

摘　　要：Based on the Lagrangian change equation of vertical vorticity deduced from the equation of three-dimensional Ertel potential vorticity （PVe）, the development and movement of vortex are investigated from the view of potential vorticity and diabatic heating （PV Q）. It is demonstrated that the asymmetric dis-tribution in the vortex of the non-uniform diabatic heating in both vertical and horizontal can lead to the vortex＇s development and movement. The theoretical results are used to analyze the development and move-ment of a Tibetan Plateau （TP） vortex （TPV）, which appeared over the TP, then slid down and moved eastward in late July 2008, resulting in heavy rainfall in Sichuan Province and along the middle and lower reaches of the Yangtze River. The relative contributions to the vertical vorticity development of the TPV are decomposed into three parts： the diabatic heating, the change in horizontal component of PVe （defined as PV2）, and the change in static stability θz. The results show that in most cases, diabatic heating plays a leading role, followed by the change in PV2, while the change of θz usually has a negative impact in a stable atmosphere when the atmosphere becomes more stable, and has a positive contribution when the atmosphere approaches neutral stratification. The intensification of the TPV from 0600 to 1200 UTC 22 July 2008 is mainly due to the diabatic heating associated with the precipitation on the eastern side of the TPV when it uplifted on the up-slope of the northeastern edge of the Sichuan basin. The vertical gradient of diabatic heating makes positive （negative） PVe generation below （above） the maximum of diabatic heating; the positive PVe generation not only intensifies the low-level vortex but also enhances the vertical extent of the vortex as it uplifts. The change in PVe due to the horizontal gradient of diabatic heating depends on the vertical shear of horizontal wind that passes through the center of diabatic heating. The horizontal gradient of diabatBased on the Lagrangian change equation of vertical vorticity deduced from the equation of three-dimensional Ertel potential vorticity （PVe）, the development and movement of vortex are investigated from the view of potential vorticity and diabatic heating （PV Q）. It is demonstrated that the asymmetric dis-tribution in the vortex of the non-uniform diabatic heating in both vertical and horizontal can lead to the vortex＇s development and movement. The theoretical results are used to analyze the development and move-ment of a Tibetan Plateau （TP） vortex （TPV）, which appeared over the TP, then slid down and moved eastward in late July 2008, resulting in heavy rainfall in Sichuan Province and along the middle and lower reaches of the Yangtze River. The relative contributions to the vertical vorticity development of the TPV are decomposed into three parts： the diabatic heating, the change in horizontal component of PVe （defined as PV2）, and the change in static stability θz. The results show that in most cases, diabatic heating plays a leading role, followed by the change in PV2, while the change of θz usually has a negative impact in a stable atmosphere when the atmosphere becomes more stable, and has a positive contribution when the atmosphere approaches neutral stratification. The intensification of the TPV from 0600 to 1200 UTC 22 July 2008 is mainly due to the diabatic heating associated with the precipitation on the eastern side of the TPV when it uplifted on the up-slope of the northeastern edge of the Sichuan basin. The vertical gradient of diabatic heating makes positive （negative） PVe generation below （above） the maximum of diabatic heating; the positive PVe generation not only intensifies the low-level vortex but also enhances the vertical extent of the vortex as it uplifts. The change in PVe due to the horizontal gradient of diabatic heating depends on the vertical shear of horizontal wind that passes through the center of diabatic heating. The horizontal gradient of diabat

关 键 词：Tibetan Plateau vortex vorticity development potential vorticity diabatic heating Lagran-gian change 

分 类 号：P432[天文地球—大气科学及气象学]