2013年湖北省两次降雪过程对比分析  

Contrast Analysis of Two Snowfall Events in Hubei 2013

作　　者：张萍萍[1] 吴翠红[1] 祁海霞[1] 王晓玲[1] 张宁[2] 

机构地区：[1]武汉中心气象台,武汉430074 [2]湖北省气象局科技与预报处,武汉430074

出　　处：《气象》2015年第4期418-426,共9页Meteorological Monthly

基　　金：湖北省气象局科技支撑项目(2014Y01)资助

摘　　要：利用常规观测资料、NCEP再分析资料、微波辐射计及多普勒雷达等资料对2013年2月7—8日干雪过程、2月18—19日湿雪过程,从水汽、不稳定、动力及温湿层结方面进行对比分析,得出如下结论:(1)2月7—8日的干雪过程水汽层次浅薄,水汽输送支仅为700 hPa弱西南气流;2月18—19日的湿雪过程水汽充沛,水汽输送支为700 hPa强西南急流和850 hPa东南气流。(2)干雪过程低层冷平流强,层结稳定。湿雪过程低层暖平流强,冷暖交汇使大气不稳定度增加。(3)干雪过程中弱暖湿气流沿深厚冷空气垫爬升,动力辐合位于中高层,次级环流的形成减弱上升运动。湿雪过程中弱冷空气楔入到强暖湿气流底部,迫使其抬升,形成深厚上升运动区,次级环流的形成增强上升运动。(4)干雪过程整层温度<0℃,700 hPa出现冷性逆温层,-10℃层位于925 hPa附近,水汽密度、液态水含量、整层水汽含量较小;湿雪过程700 hPa出现暖性逆温层,-10℃层位于500 hPa附近,水汽密度、液态水含量、整层水汽含量较大。在上述研究的基础上给出了干、湿雪形成的三维物理模型,该模型从温湿(风)垂直层结上面体现出了干、湿雪形成的主要环境背景差异,对于干、湿雪预报具有一定的参考价值。Based on conventional weather chart,NCEP reanalysis data,microwave radiometer products and Doppler radar observations,the water vapor,thermal and dynamic conditions,temperature and humidity stratification during 7—8(dry snow) and 18—19(wet snow) February 2013 are comparatively analyzed.The results show that:(1) The vapor transportation branch in dry snow process is weak southwest air current at 700 hPa,but the vapor transportation branch in wet snow process is the strong southwest air current at 700 hPa and the southeast air current at 850 hPa with sufficient moisture.(2) There is strong cold advection and stable atmospheric layer in dry snow process.However,strong warm advection exits in wet snow process in which cold and warm flow intersection makes atmospheric instability enhanced.(3)The southwest current ascends on the cooling cushion in dry snow process with convergence at middle-high levels,and the secondary circulation inhibits ascending motion.In wet snow process,the cold air inserts the bottom of warm flow,making warm flow lifted,and the secondary circulation supplies a continuous and powerful updrafts.(4) The temperature is lower than 0℃ at all levels with cold inversion layer and low vapor density,liquid water content and water vapor content at all levels in dry snow,and the level of -10℃ is found at 925 hPa.On the contrary,warm inversion layer exists in wet snow with high vapor density,liquid water content and water vapor content at all levels,and the level of -10℃ is at 500 hPa.Finally,three-dimensional physical model for the formation of dry snow and wet snow is built based on the above researches.The model reflects the main environmental background difference of temperature and humidity air stratification,which has certain reference significance for dry and wet snow forecasting.

关 键 词：干雪 湿雪 次级环流 液态水含量 物理模型 

分 类 号：P458.121[天文地球—大气科学及气象学]