气象与环境学报
氣象與環境學報
기상여배경학보
JOURNAL OF METEOROLOGY AND ENVIRONMENT
2011年
4期
66-71
,共6页
暴雪%边界层%回流天气%东风%渤海
暴雪%邊界層%迴流天氣%東風%渤海
폭설%변계층%회류천기%동풍%발해
Snowstorms%Boundary layer%Backflow weather%Easterly wind%The Bohai Sea
2008年12月20—21日和2010年1月3日天津地区分别出现了历史同期罕见的暴雪天气。为了提高对这种极端天气发生机理的认识,利用多种资料对这两次天气过程进行了分析。结果表明:两次暴雪过程均属于回流型降雪,但环流形势和影响系统的演变却不尽相同。影响系统分别为高空横槽(高空槽)、850 hPa切变(850 hPa低涡切变)和地面倒槽(地面气旋),水汽源自700 hPa西南气流和边界层东风的水汽输送。由于两次过程均与边界层东风相伴,特别对渤海西岸边界层东风对降雪天气的影响和作用进行探讨,表明偏东风不仅为本地输送一定量级的水汽,同时这种具有冷湿特征的东风还会与内陆具有暖湿结构的偏南风形成地面辐合线,加强地面的动力抬升作用,产生上升运动,有利于雨雪天气的加强和维持,因此可以认为边界层东风对暴雪的发生发展起到了显著的作用。
2008年12月20—21日和2010年1月3日天津地區分彆齣現瞭歷史同期罕見的暴雪天氣。為瞭提高對這種極耑天氣髮生機理的認識,利用多種資料對這兩次天氣過程進行瞭分析。結果錶明:兩次暴雪過程均屬于迴流型降雪,但環流形勢和影響繫統的縯變卻不儘相同。影響繫統分彆為高空橫槽(高空槽)、850 hPa切變(850 hPa低渦切變)和地麵倒槽(地麵氣鏇),水汽源自700 hPa西南氣流和邊界層東風的水汽輸送。由于兩次過程均與邊界層東風相伴,特彆對渤海西岸邊界層東風對降雪天氣的影響和作用進行探討,錶明偏東風不僅為本地輸送一定量級的水汽,同時這種具有冷濕特徵的東風還會與內陸具有暖濕結構的偏南風形成地麵輻閤線,加彊地麵的動力抬升作用,產生上升運動,有利于雨雪天氣的加彊和維持,因此可以認為邊界層東風對暴雪的髮生髮展起到瞭顯著的作用。
2008년12월20—21일화2010년1월3일천진지구분별출현료역사동기한견적폭설천기。위료제고대저충겁단천기발생궤리적인식,이용다충자료대저량차천기과정진행료분석。결과표명:량차폭설과정균속우회류형강설,단배류형세화영향계통적연변각불진상동。영향계통분별위고공횡조(고공조)、850 hPa절변(850 hPa저와절변)화지면도조(지면기선),수기원자700 hPa서남기류화변계층동풍적수기수송。유우량차과정균여변계층동풍상반,특별대발해서안변계층동풍대강설천기적영향화작용진행탐토,표명편동풍불부위본지수송일정량급적수기,동시저충구유랭습특정적동풍환회여내륙구유난습결구적편남풍형성지면복합선,가강지면적동력태승작용,산생상승운동,유리우우설천기적가강화유지,인차가이인위변계층동풍대폭설적발생발전기도료현저적작용。
Rarely intense snowstorms occur on December 20-21,2008 and January 3,2010 respectively in Tianjin.These two weather processes were analyzed based on multiple data in order to understand the mechanism of this weather.The results indicate that two snowfall events are both backflow-type snowstorms despite synoptic patterns and major weather systems in each case are distinctly different.Main weather systems are the horizontal trough at the upper level,850 hPa shear and surface inverted trough(surface cyclone).Moreover,southwesterly airflow in 700 hPa provides moisture condition.Two processes are both accompanied by boundary layer easterly wind.The easterly wind not only transports some moisture,but also produces the surface convergence line with the warm and damp southerly wind,which could strengthen the lifting action and could generate lifting motion.Therefore,it is favorable to strengthen and maintain this weather process.Boundary layer easterly wind is playing a significant role in the initiation and development of snowstorm.