摘要
利用2000-2016年常规观测、台站降水资料和NCEP的1°×1°再分析资料,对影响东北的北上温带气旋暴雪进行了统计研究。根据500 hPa环流形势分为低涡型、浅槽型和深槽型暴雪,并对这三种类型暴雪的气旋路径、强度变化、降水分布、水汽输送和热动力特征进行了详细分析。结果表明:低涡型和深槽型暴雪气旋路径为东北路,浅槽型暴雪气旋路径偏东,各类暴雪的气旋强度变化和降水分布因路径不同而有所差异;降雪最强时,低涡型和深槽型暴雪700和850 hPa都有低涡,浅槽型暴雪700 hPa为低槽。低涡型和深槽型暴雪中水汽通量散度辐合区与低层低涡气旋性闭合环流引起的辐合密切相关。浅槽型暴雪的水汽辐合源于槽前辐合;低涡型和深槽型暴雪发生在假相当位温暖舌中,浅槽型暴雪发生在较平直的假相当位温场中,深槽型和浅槽型暴雪的锋区要强于低涡型暴雪。降雪最强时,低涡型暴雪有1支高空急流,深槽型暴雪有2支高空急流,浅槽型暴雪高空急流有1支或2支。三类暴雪中心都位于北支高空急流入口区右侧或南支高空急流出口区左侧的位置。综合统计结果提出影响东北的北上温带气旋暴雪概念模型。
This paper investigated the statistical characteristics of snowstorms affected by northward extratropical cyclones in Northeast China by using the conventional observation data, station precipitation data and NCEP 1°×1° reanalysis data from 2000 to 2016. Snowstorms were classified into low vortex, shallow trough and deep trough patterns according to circulation patterns at 500 hPa. In addition, cyclone tracks, intensity change and associated precipitation distribution, water vapor transport and thermodynamic characteristics of snowstorms were analyzed in detail. The results showed that cyclones of low vortex and deep trough patterns moved northeastward while those of shallow trough pattern moved east-northeastward. Intensity change and precipitation distribution of all types of cyclone snowstorms resulted from moving paths of cyclones. Low vortex and deep trough pattern existed a low vortex at 700 hPa and 850 hPa whereas shallow though pattern exhibited a low trough at 700 hPa as the snowfall was at its peak. Water vapor flux convergence region of low vortex and deep trough pattern snowstorms were related to the convergence of cyclonic circulation and those of shallow trough pattern were mainly associated with convergence in front of troughs in low level. Snowstorms of low vortex and deep trough pattern occurred in warm tongue of pseudo-equivalent potential temperature while that of shallow trough pattern concentrated in relatively flat pseudo-equivalent potential temperature field. Front zone of deep trough and shallow trough pattern were more intensive than that of low vortex pattern. Low vortex and deep trough pattern snowstorm had one and two branches of upper level jet streams respectively, while shallow trough pattern had one or two upper level jet streams. The snowstorm centers were located on the right side to the entrance area of north branch or left side to the exit area of the south branch of upper jet stream. Conceptual model of snowstorms produced by northward extratropical cyclones in Northeast China was proposed finally.
作者
付亮
赵宇
杨成芳
赵玲
FU Liang;ZHAO Yu;YANG Chengfang;ZHAO Ling(Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)/Key Laboratory of Meteorological Disaster, Ministry of Education(KLME), Nanjing University of Information Science & Technology, Nanjing 210044, Jiangsu, China;Shandong Provincial Meteorological Observatory, Jinan 250031, Shandong, China;Heilongjiang Provincial Meteorological Observatory, Harbin 150030, Heilongjiang, China)
出处
《高原气象》
CSCD
北大核心
2018年第6期1705-1715,共11页
Plateau Meteorology
基金
国家自然科学基金项目(41475038
41475090)
关键词
东北暴雪
北上温带气旋
水汽通量
假相当位温
高空急流
Northeast China snowstorm
northern extratropical cyclone
water vapor flux
pseudo-equivalent potential temperature
upper level jet stream
