2013年云南冬季四次降雪天气过程对比分析  

Comparative Analysis of Four Snow Events in Yunnan in the Winter of 2013

作　　者：潘娅婷[1] 杨芳园[1] 李晓鹏[1] 邹灵宇 

机构地区：[1]云南省昆明市气象台,昆明650500

出　　处：《高原山地气象研究》2017年第2期22-28,共7页Plateau and Mountain Meteorology Research

基　　金：昆明市区域创新与科技惠民重点项目(TQ2015 1 S 00169);云南省气象局科研项目(TQ201603)共同资助

摘　　要：利用NCEP 1°×1°资料和实况观测资料,针对2013年冬季云南4次降雪过程,使用诊断和对比的方法,分析研究4次降雪过程在形成机理等方面的异同点。结果表明:4次降雪中南支槽型降雪强度和范围明显强于非南支槽型;700h Pa上高度场北高南低型和锋区密集型为主要环流形势;南支槽前的西南暖湿气流与北方冷空气的交汇,会导致降水的明显加强。在锋面附近形成的中尺度垂直环流系统,随着北方冷空气进一步南下,θ_(se)线陡立区的存在或移动引起南方暖湿气流带来的水汽凝结和不稳定能量的释放,从而为降雪提供了足够的抬升凝结条件,降雪或强降雨就发生在θ_(se)线陡立区附近以及暖湿不稳定区域;强大的地面冷高压南压和地面冷空气的参与,能够为降雪提供有利的温度条件,更有利于降雪天气的产生和维持。By using upper air observational data, surface observational data,NCEP 1°× 1° reanalysis data, 4 snow proces-ses in Yunnan in winter 2013 were comparative analyzed and diagnosed. The similarities and differences were analyzed about formation mechanism of 4 snow processes,and so on. The results showed that in the 4 snow processes in Yunnan, snowing inten-sity and area caused by the south trough pattern was stronger than no south trough pattern on 500hPa obviously, the north high-er and south lower about height fields,the front area density on 700hPa. Precipitation was obviously strengthened by the south west warm meets cold air. The strong water vapor flux convergence belt and area can better indicate the snow processes of Yun-nan. The snow always appears in the area of strong water vapor convergence and closed to the side of strong cold air in the east and north of the convergence center. Because the updraft and the downdraft in the south and the north coexisted, the meso - scale vertical circulation near the front area may establish. When the cold air from the north moved to the south, the θse sharp-ness area also moved to the south, the coupling between the right entrance of the upper jet and the vertical circulation of the frontal zone, and then caused the water vapor brought by the south warm moist airflow to condense and the unstable energy to release, providing enough uplift condensation condition for the snow. Temperature condition was provided by moving to south a-bout stronger ground cold high and involving about ground cold air,and were in favor of generating and supporting.

关 键 词：诊断分析 南支槽 水汽通量辐合 θse线陡立区 地面冷空气 

分 类 号：P458.3[天文地球—大气科学及气象学]