Dynamical and Thermal Problems in Vortex Development and Movement. Part II: Generalized Slantwise Vorticity Development  

作　　者：吴国雄 郑永骏 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15-25,共11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：The development of vertical vorticity under adiabatic condition is investigated by virtue of the view of potential vorticity and potential temperature （PV-θ） and from a Lagrangian perspective. A new concept of generalized slantwise vorticity development （GSVD） is introduced for adiabatic condition. The GSVD is a coordinate independent framework of vorticity development （VD）, which includes slantwise vorticity development （SVD） when a particle is sliding down the concave slope or up the convex slope of a sharply tilting isentropic surface under stable or unstable condition. The SVD is a special VD for studying the severe weather systems with rapid development of vertical vorticity. In addition, the GSVD clarifies VD and SVD. The criteria for VD and SVD demonstrate that the demand for SVD is much more restricted than the demand for VD. When an air parcel is moving down the concave slope or up the convex slope Of a sharply tilting isentropic surface in a stable stratified atmosphere with its stability decreasing, or in an unstable atmosphere with its stability increasing, i.e., its stability θz approaches zero, its vertical vorticity can develop rapidly if its CD is decreasing. The theoretical results are employed to analyze 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 change of PV2 contributed to the intensification of the TPV from 0000 to 0600 UTC 22 July 2008 when it slid upward on the upslope of the northeastern edge of the Sichuan basin, since the changes in both horizontal vorticity ~？~ and baroclinity Os have positive effects on the development of vertical vorticity. At 0600 UTC 22 July 2008, the criterion for SVD at 300 K isentropic surface is satisfied, meaning that SVD occurred and contributed significantly to the development of vertical vorticity. The appearance of the stronger signals concerniThe development of vertical vorticity under adiabatic condition is investigated by virtue of the view of potential vorticity and potential temperature （PV-θ） and from a Lagrangian perspective. A new concept of generalized slantwise vorticity development （GSVD） is introduced for adiabatic condition. The GSVD is a coordinate independent framework of vorticity development （VD）, which includes slantwise vorticity development （SVD） when a particle is sliding down the concave slope or up the convex slope of a sharply tilting isentropic surface under stable or unstable condition. The SVD is a special VD for studying the severe weather systems with rapid development of vertical vorticity. In addition, the GSVD clarifies VD and SVD. The criteria for VD and SVD demonstrate that the demand for SVD is much more restricted than the demand for VD. When an air parcel is moving down the concave slope or up the convex slope Of a sharply tilting isentropic surface in a stable stratified atmosphere with its stability decreasing, or in an unstable atmosphere with its stability increasing, i.e., its stability θz approaches zero, its vertical vorticity can develop rapidly if its CD is decreasing. The theoretical results are employed to analyze 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 change of PV2 contributed to the intensification of the TPV from 0000 to 0600 UTC 22 July 2008 when it slid upward on the upslope of the northeastern edge of the Sichuan basin, since the changes in both horizontal vorticity ~？~ and baroclinity Os have positive effects on the development of vertical vorticity. At 0600 UTC 22 July 2008, the criterion for SVD at 300 K isentropic surface is satisfied, meaning that SVD occurred and contributed significantly to the development of vertical vorticity. The appearance of the stronger signals concerni

关 键 词：potential vorticity vorticity development slantwise vorticity development generalized slant-wise vorticity development 

分 类 号：P432[天文地球—大气科学及气象学]