一次极端降水过程中不同相态降水过程的锋生特征对比研究  

A comparative study on frontogenesis characteristics in different phase during an extreme precipitation process

作　　者：梁红丽[1] 祁文[2] 陈艳[3] 周宁芳 连钰 LIANG Hongli;QI Wen;CHEN Yan;ZHOU Ningfang;LIAN Yu(Yunnan Meteorological Observatory, Kunming 650034, China;Tongling Meteorological Office of Anhui, Tongling 244100, China;Meteorological Science Institute of Yunnan, Kunming 650034, China;National Meteorological Center, Beijing 100081, China)

机构地区：[1]云南省气象台,云南昆明650034 [2]安徽省铜陵市气象局,安徽铜陵244100 [3]云南省气象科学研究所,云南昆明650034 [4]国家气象中心,北京100081

出　　处：《自然灾害学报》2018年第2期149-160,共12页Journal of Natural Disasters

基　　金：国家自然科学基金项目(41365007;41365006)~~

摘　　要：2015年1月8日夜间~10日,云南出现暴雨和暴雪并存天气,是1961年以来1月最极端的一次降水过程,利用NCEP/NCAR再分析资料,对不同相态降水过程中锋生作用及其伴随的次级环流特征进行对比分析,探讨强雨雪产生机制。结果表明,孟加拉湾至滇南的水汽输送偏离气候平均度达3σ,滇南锋区中心强度为-5×10-5K·m-1,异常冷暖气流在云南交汇造成此次强雨雪天气。进一步地锋生函数分析表明,2015年初强雨雪中,暴雨前期低层水平辐合及上升运动加剧,使降水出现峰值,此后水平变形场(主要是切变变形)的增长,使锋生作用维持,但强度明显减弱;对于暴雪而言,第一次降雪峰值的形成主要是倾斜项作用;第二次降雪峰值的形成则主要是水平变形项中的伸长变形增长和倾斜项作用。次级环流上升支处的强上升运动为强雨雪天气提供了有利的动力条件。A rainstorm and snowstorm weather occurred in Yunnan from the evening of 8 to 10 January 2015, which was the most extreme precipitation process in January since 1961. Based on NCEP/NCAR reanalysis data, fronto- genetic function and characteristics of front secondary circulation in different phase were diagnosed. Furthermore, the production mechanism of strong rain and snow was discussed. It was showed that the water vapor transport from Bay of Bengal to South Yunnan deviating from climatological mean degree reached 3o-, center intensity of frontal zone in South Yunnan was -5 ×10^-5K·m^-1, namely anomaly cold and warm airflow intersected in Yunnan, which made this strong rain and snow weather. Furthmore, frontogenesis function analysis showed that at the prophase of heavy rain, horizontal convergence in lower layer and ascending motion aggravated, which made precipita- tion reach peak. Thereafter, horizontal deformation field, especially shear deformation＇ s increasing made frontoge- netic function maintain, but strength was obviously weak. For the snowstorm, the first peak formation of snowfall was mainly inclined item function, while the second, they were horizontal deformation and inclined items＇ functions, among horizontal deformation item, it was mostly growth of elongation deformation. In addition, strongly aseending motion in front secondary circulation＇ s ascending branch provided favorably dynamic condition to strong rain and snow weather.

关 键 词：极端降水 异常性 不同相态 锋生函数 锋面次级环流 

分 类 号：P458[天文地球—大气科学及气象学] X43[环境科学与工程—灾害防治]