浙江2011-01-20强降雪过程降雪带南压成因的诊断分析  

Diagnostic Analysis of the Causes for Heavy Snowfall Belt Southward in Zhejiang on January 20th,2011

作　　者：蓝俊倩 余健 王健疆 

机构地区：[1]衢州市气象局,浙江衢州324000

出　　处：《气象与环境科学》2011年第4期52-58,共7页Meteorological and Environmental Sciences

基　　金：基于雷达资料和自动站的面雨量差值研究(2011QM06)资助

摘　　要：利用自动站、Micaps、雷达风廓线等资料和6 h间隔的NCEP1°×1°再分析资料,对浙江2011年1月20日强降雪过程中降雪带南压的成因进行了诊断分析。结果表明:高空槽、中低层切变配合近地面的冷空气渗透影响是强降雪发生的有利天气尺度背景;强降雪发生在低空西南急流左侧水汽通量散度的辐合区内,且低空西南急流的南压领先于降雪带的南压,700 hPa风速辐合线位置与降雪带前沿位置有较好的一致性;湿位涡斜压项的发展和移动与降雪带的南压有较好的一致性;850 hPa冷平流的南扩和800—600 hPa之间强暖平流的南伸,推动了降雪带的南压;雷达风廓线指示的低层冷平流作用比单站降雪开始时间早数小时,对本站温度条件的改变和降雪区的南压趋势有提前预示作用,可作为类似过程降水性质转换的参考依据之一。This paper uses automatic station data, Micaps data, radar wind profiler data and 6 h intervals NCEP 1° ×1 ° reanalysis data to analyze and diagnose the causes for snowfall belt southward of Zhejiang on 20th January, 2011. Results show that high-level trough and low-level wind shear with the infiltration of cold air near ground provide the favorable weather scale background which heavy snow occurred to. Heavy snowfall occurred in the water vapor flux divergence convergence zone which on the left of the low-southwestern jet and jet stream southward ahead of the snowfall belt southward. The 700 hPa wind convergence line position with the leading edge of snowfall belt are in good agreement. The develop- ment and movement of moist potential vorticity baroclinic term is in good relationship with snowfall belt southward. South stretch of 850 hPa cold advection and strong warm advection between 800 hPa to 600 hPa promote the snowfall belt southward. Radar wind profiles indicated low-level cold advection began several hours earlier than the single station snowfall. Low-level cold advection can indicate the site ten〉 perature change and snowfall belt southward in advance, so it could be used as a one of the reference that can indicate the conversion of the nature of precipitation in other similar snowfall processes.

关 键 词：强降雪 西南急流 温度平流 湿位涡 风廓线 

分 类 号：P458.3[天文地球—大气科学及气象学]