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| An Analysis of the Eddy Kinetic Energy Budget of a Southwest Vortex during Heavy Rainfall over South China |
| FU Shen-Ming,SUN Jian-Hua,ZHAO Si-Xiong,LI Wan-Li |
| Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029;Graduate University of Chinese Academy of Sciences, Beijing 100049,Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029,Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029,Graduate University of Chinese Academy of Sciences, Beijing 100049；Cold and Arid Regions Environment and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000 |
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Abstract Based on the 6-hour-interval reanalysis data with 1o×1o resolution from the National Center for Environmental Prediction/the National Center for Atmospheric Research (NCEP/NCAR), the eddy kinetic energy (EKE) budget of a southwest vortex (SWV) that caused heavy rainfall in Guangxi over South China (from 1200 UTC 11 to 0000 UTC 13 June) is calculated. The results are as follows: (a) The SWV is a kind of subtropical vortex, with characteristics of both an extratropical vortex and a tropical vortex. (b) In the case examined, large-scale circulation and other perturbation fields contributed to the formation and development of the SWV. (c) When the SWV moved from weak large-scale circulation EKE areas to strong ones, the EKE of the SWV increased, and vice versa. (d) Sub-grid processes and frictional dissipation were the main sinks of the SWV EKE, which contributed to the decay of the SWV. (e) The residual term (RES) and the Total (composite effect of all right hand side (rhs) terms except the RES in the EKE equation) varied almost in the same tendency, which kept the EKE varying in a moderate way. (f) The EKE between 550 hPa and 850 hPa increased most intensively, corresponding to the vertical stretching of the SWV.
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Received: 16 March 2009
Revised: 15 April 2009
Accepted: 18 April 2009
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