2008年初昆明准静止锋生消及移动成因分析

On the causes of frontogenesis,frontolysis and movement of Kunming Quasi-Stationary Front in early 2008

利用2008年1—2月常规观测数据、ERA-Interim再分析数据和DEM地形高度数据,从环流形势、天气系统及锋生函数诊断3方面分析了2008年初昆明准静止锋生消及移动的成因.结果表明:锋面位置和锋面前后冷暖气团的相对强弱、锋后东风的强度、南支槽强度和位置、西太平洋副热带高压和各系统配置有关;锋生初期,风场的变化快于温度场,东风的强度和厚度可指示冷空气的强度和厚度;锋生区东西跨度约2~3个经度,可视为静止锋的锋区宽度,当锋生区整体西进至104°E以西,锋面可越上云贵高原西部,西进时锋生区向上可超过700 h Pa;水平辐散项对锋生和锋面西进更有预见性,水平变形项中切变变形起主要作用,垂直运动倾斜项对锋消的作用较大,非绝热加热项对锋面的生消及西进均有正的贡献.

Based on the ground meteorological elements of January and February,2008, interim daily reanalysis data and DEM data, this paper has explored the causes of frontogenesis, frontolysis and movement of Kunming Quasi-Stationary Front in early 2008 from three aspects, namely, circulation situation, weather system and frontogenesis function.The results indicate that the movements of front are related to the strength of cold and warm air; the strength of east wind, intensity and location of south westerly trough, subtropical high and configurations a- mong weather systems.At the beginning of frontogenesis,change of wind filed is more rapid than that of tempera- ture filed, and the strength and thickness of east wind can indicate the strength and thickness of cold air. Fronto- genetieal area is about 2--3 longitudes, which can be seen as the width of front. When the whole frontogenetical area moves to the west of 104~E ,the font can climb to the western Yunnan-Guizhou Plateau, and frontogenetical area is above 700 hPa when front moving westward.Divergence term is of predictable significance to frontogenesis and movement. Wind shear is important to horizontal deformation term, and vertical motion tilting term makes a difference to frontolysis, non-adiabatic heating term to frontogenesis, frontolysis and movement of front.