两次滇黔准静止锋锋区结构的对比分析  

Contrastive Analysis on Frontal Structure of Quasi-Stationary Front in Two Precipitation Processes of Yunnan-Guizhou

作　　者：杜小玲 蓝伟 

机构地区：[1]贵州省气象台,贵州贵阳550002 [2]贵州省气象局,贵州贵阳550002

出　　处：《高原气象》2010年第5期1183-1195,共13页Plateau Meteorology

基　　金：国家自然科学基金项目(40930950;40865003)资助

摘　　要：利用常规观测资料和NCEP 1°×1°格点再分析资料,对滇黔准静止锋上的低温雨雪冰冻天气（简称08冻雨过程）及阴雨天气（简称09阴雨天气）的锋区结构特征及准静止锋的形成和维持进行了对比分析。锋区结构共同点表现在：在水平方向上,准静止锋在850 hPa的水平温度梯度大,是等温线密集区;锋后低空逆温显著,平均逆温强度达2-8℃,逆温中心位于贵州东部-湖南西部之间。在垂直方向上,锋区表现为等sθe的密集区,锋区在经向上向北倾斜,向上伸展高度接近600 hPa附近;准静止锋天气一旦持续,锋区在850 hPa上表现为正的涡度带以及水平风的辐合区;与准静止锋锋生密切相关的锋生函数为正值。不同点表现在：近地面温度场垂直结构的差异是导致准静止锋降水属性不同的重要原因;在08冻雨过程中,温度场在垂直方向不仅具有＂冷暖冷＂的结构特征,还具有较深厚的＂一层模式＂结构特征。在09阴雨天气中,低空温度场存在冷中心,但温度高于0℃。在锋区结构上,08冻雨过程表现为宽而平缓且向北倾斜,09阴雨天气在750 hPa以下表现为狭窄而陡峭,并在16°-17°N之间存在副热带锋区。造成锋区结构特征差异的重要原因在于,锋生函数的水平辐合项和变性项对准静止锋的贡献存在差异。The frontal structure features of quasi-stationary front in two precipitation processes of Yunnan and Guizhou and its formation and maintenance are analysed.The two precipitation processes are the cryogenic freezing rain and snow weather at the beginning of 2008 and low-temperature and rain weather at the beginning of the spring in 2009.There are both similar and different features.The similar features are： In the horizontal direction, 850 hPa temperature gradient are dense and the frontal zone are the compact district of isotherm.Behind the frontal zone,the low level inversion is very significant,the average inversion intensity is 2～8℃,its center lies between the eastern Guizhou and the western Hunan.In the vertical direction,the frontal zone are the compact district of the pseudoequivent potential temperature,it slopes northward and stretch upwards near 600 hPa.The frontal zone are the positive vorticity zone and the convergence zone of the horizontal wind on 850 hPa when the quasi-stationary front continus.The frontogenetical function that connected with quasi-stationary front both are positive.Yet the different feature are： the temperature difference of the surface layer is an important reason.In the vertical direction,the temperature field have not only cold-warm-cold characteristics but also one-level model characteristic in 2008,on the contrary,the temperature field has not the two characteristics in 2009.The low-level temperature field has cold center,which is above 0℃.The frontal structure are wide and gently slope northward in 2008,but it is narrow and sharp below 750 hPa in 2009.At the same time,there is an low subtropic frontal zone between 16°-17°N.The important difference causing frontal structure is that the horizontal convergence and denaturation of the frontogenetical function are difference to quasi-stationary front.

关 键 词：滇黔 准静止锋 锋区结构特征 锋生函数 

分 类 号：P458.3[天文地球—大气科学及气象学]