干旱气象
榦旱氣象
간한기상
GANSU METEOROLOGY
2014年
1期
87-92
,共6页
暴雨%垂直速度%位温%水汽通量散度
暴雨%垂直速度%位溫%水汽通量散度
폭우%수직속도%위온%수기통량산도
rainstorm%vertical velocity%potential temperature%moisture flux divergence
2011年6月23日下午到夜间，受蒙古低涡东移南下天气过程及冷暖空气共同作用影响下，北京地区出现了强雷雨天气过程，局部地区降雨量达到大暴雨标准。此次大暴雨过程具有突发性、局地性、短时性和高雨强等特点。利用常规天气资料、fnl再分析6 h资料等，对此次大暴雨过程进行了分析，并对其成因作了初步讨论。结果表明：东移南下的蒙古低涡及北京北部、贝加尔湖以东的外蒙古境内的阻塞高压为此次天气过程的影响系统，北京地区处于低槽前部的不稳定区。由垂直速度场可以看出，北京地区处于垂直速度大值中心，同时位温随高度增加而减小的分布状况，表明暴雨发生时北京地区大气层结是极不稳定的，地面低压辐合带配合高空东移的横槽造成高低空辐散带叠加，产生了极强的上升运动，有利于大暴雨的发生发展。近地面东南风将渤海的水汽源源不断地输送到北京地区，借助强的上升运动，在高空呈现很强的水汽通量辐合，为大暴雨的发生提供了充足的水汽条件。
2011年6月23日下午到夜間，受矇古低渦東移南下天氣過程及冷暖空氣共同作用影響下，北京地區齣現瞭彊雷雨天氣過程，跼部地區降雨量達到大暴雨標準。此次大暴雨過程具有突髮性、跼地性、短時性和高雨彊等特點。利用常規天氣資料、fnl再分析6 h資料等，對此次大暴雨過程進行瞭分析，併對其成因作瞭初步討論。結果錶明：東移南下的矇古低渦及北京北部、貝加爾湖以東的外矇古境內的阻塞高壓為此次天氣過程的影響繫統，北京地區處于低槽前部的不穩定區。由垂直速度場可以看齣，北京地區處于垂直速度大值中心，同時位溫隨高度增加而減小的分佈狀況，錶明暴雨髮生時北京地區大氣層結是極不穩定的，地麵低壓輻閤帶配閤高空東移的橫槽造成高低空輻散帶疊加，產生瞭極彊的上升運動，有利于大暴雨的髮生髮展。近地麵東南風將渤海的水汽源源不斷地輸送到北京地區，藉助彊的上升運動，在高空呈現很彊的水汽通量輻閤，為大暴雨的髮生提供瞭充足的水汽條件。
2011년6월23일하오도야간，수몽고저와동이남하천기과정급랭난공기공동작용영향하，북경지구출현료강뇌우천기과정，국부지구강우량체도대폭우표준。차차대폭우과정구유돌발성、국지성、단시성화고우강등특점。이용상규천기자료、fnl재분석6 h자료등，대차차대폭우과정진행료분석，병대기성인작료초보토론。결과표명：동이남하적몽고저와급북경북부、패가이호이동적외몽고경내적조새고압위차차천기과정적영향계통，북경지구처우저조전부적불은정구。유수직속도장가이간출，북경지구처우수직속도대치중심，동시위온수고도증가이감소적분포상황，표명폭우발생시북경지구대기층결시겁불은정적，지면저압복합대배합고공동이적횡조조성고저공복산대첩가，산생료겁강적상승운동，유리우대폭우적발생발전。근지면동남풍장발해적수기원원불단지수송도북경지구，차조강적상승운동，재고공정현흔강적수기통량복합，위대폭우적발생제공료충족적수기조건。
From afternoon to night of June 23,2011,the strong thunderstorm weather process occurred in Beijing due to the Mongolia vortex moving eastward and southward and the effect of cold and warm air,and during the storm weather process,localized rainfall reached the standard of heavy rainstorm.This rainstorm weather had some characteristics including the suddenness,local,short-term and high rainfall intensity.Based on conventional weather information and the FNL analysis data of six hours,the storm weather process was analyzed and a preliminary discussion about its formation causes was made in this paper.The results show that the Mongo-lia vortex moving eastward and southward and the blocking high over Mongolia resulted in this weather process,Beijing happened to be at the unstable region in front of the trough.From the analysis of vertical velocity,Beijing was located in the center of maximum verti-cal velocity,and the potential temperature decreased with height increase,which indicated that the atmospheric stratification was ex-tremely instable over this region when heavy rainfall occurred.Ground pressure convergence zone cooperated with the transverse trough moving eastward over the up level resulted in divergence zone overlapping,which produced the strong ascending motion,and it was conducive to the development of rainstorm.The southeast wind near the ground transported vapor from Bohai to the Beijing area,and with the strong ascending motion,the strong convergence of moisture flux occurred at up level,which provided adequate moisture con-ditions for the rainstorm.
