利用NCEP.DOE再分析数据分析了2008年1月26~28日中国南方罕见的低温雨雪冰冻天气的扰动能量的生成以及各种能量之间的转换。在急流中平均动能(Km)先转换成相互作用动能(Ki)然后再转化成扰动动能(Ke)。相互作用动能流是顺急流方向的。位势高度平流和有效位能与扰动动能的转化生成的扰动动能比平均动能转化的要小一个量级。中国中南部扰动有效位能(Ae)的产生主要由平均有效位能(Am)间接提供,其中相互作用有效位能(Ai)流起到了关键作用。生成的扰动有效位能在26日12:00(协调世界时)主要来源于两个地区:一个位于青藏高原,另一个位于中国东北部。随着两个主要源地的向东移动,转化也向东移动。相互作用有效位能流的方向同时存在逆急流方向和顺急流方向。
Local energy generation and conversion in freezing rain and snowstorms over southern China between 26 and 28 January 2008 were investigated using the NCEP-DOE Reanalysis 2 data. In the subtropical jet, the mean kinetic energy (Km) converts energy into interaction kinetic energy (Ki)flow, and then transient-eddy kinetic energy (Ke) is gained from the Ki flow. The Ki flow has the same orientation as the subtropical jet. The term for baroclinic conversion between Ke and Ae (ωeαe) and the geopotential height advection terms were about one order of magnitude lower than the terms for the conversions between Km and Ki (C(Km, Ki)) and between Ki and Ke (C(Ki, Ke)). The transient-eddy available potential energy (Ae) mainly obtained energy indirectly from the mean available potential energy (Am) over central-southern China because of the interaction available potential energy (Ai) flow. At 1200 UTC on 26 January 2008, there were two sources ofAi flow, one over the Tibetan Plateau and the other over northeastern China. The two sources shifted eastward over time so the energy conversions also shifted eastward. The Ai flows had two orientations, one being the orientation opposite that of the subtropical jet and the other in the same direction as the subtropical let.