CAJ | 학술논문

利用北京地区5 min 间隔的自动气象站降水观测资料，SA 雷达观测资料、FY-2卫星 TBB（Temperature of Black Body）资料、常规气象探空资料和1°×1°NCEP／NCAR 最终分析资料，对2006—2013年发生的10次极端暴雨事件（14个区（县）中，任意一个区县代表站24 h 内降水量≥100 mm，且暴雨区内至少有一个自动气象站降水强度≥40 mm／h）的基本特征进行了对比分析。结果表明：（1）长生命周期的单体或多单体组织合并的中尺度对流系统（第Ⅰ类中尺度对流系统）形成的暴雨中心一般位于北京西部山前地区或中心城区，这种分布与低空偏东气流的地形强迫作用或城市强迫作用有关；“列车效应”对应的多单体中尺度对流系统（第Ⅱ类中尺度对流系统）形成的极端暴雨事件往往与两次不同属性的降水过程有关：锋前暖区对流过程和锋面附近的对流过程。因此，降水分布往往平行于低空急流轴或锋面。（2）第Ⅰ类中尺度对流系统形成的极端暴雨过程局地性更强，全市平均降水量远小于暴雨量级（50 mm），其中，由混合型降水主导的极端暴雨事件一般是由几乎不移动的长生命周期单体反复生消造成的，对流高度相对较低；而深对流主导的极端暴雨事件一般由多单体组织、合并、加强造成，由于对流单体的上冲云顶很高，最低 TBB 一般低于－55℃，这类极端暴雨事件的短时强降水具有显著的间歇性：第一阶段的强降水与单体对流发展过程对应，以后的短时强降水与对流单体组织、合并过程对应。（3）“列车效应”对应的多单体中尺度对流系统暴雨过程，初始阶段一般表现为相互独立的两个对流带，即与锋面系统对应的对流带和与低空急流轴对应的暖区对流带，随着锋面对流带逐渐向暖区对流带移动，低空冷空气逐渐侵入到暖区对流带中，两条对流云带逐渐合并，对流活动进一步发展；或者由于暖区对流带截断锋面对流带的水汽入流，造成锋面对流减弱，而暖区对流带组织性更强，发展更加旺盛。与第Ⅰ类中尺度对流系统形成的极端暴雨过程不同，这类暴雨过程往往造成全市平均降水量达到暴雨（≥50 mm）甚至大暴雨（≥100 mm）。（4）不同类型的极端暴雨过程，大尺度水汽输送条件不同：“列车效应”造成的暴雨过程多数情况下由源于孟加拉湾和源于西太平洋的两支暖湿季风气流共同构成，大尺度水汽供应充沛；而第Ⅰ类中尺度对流系统中的混合型降水造成的暴雨过程的水汽来源主要与低空东南气流造成的近海水汽输送有关；第Ⅰ类中尺度对流系统中的深对流主导的深对流暴雨过程中整层水汽含量并不大，多数情况下水汽输送仅出现在对流层低层甚至仅在近地面层内。（5）大多数情况下，无论哪类性质的极端暴雨过程，在强降水发生时刻，雷达强回波高度一般在4 km 以下，仅有极个别时刻强回波中心高于5 km。极端暴雨过程中，环境大气对流有效位能（CAPE）的大小一般与对流发展高度（雷达回波顶高）具有较好的对应关系，但与强降水发生时刻回波强度、最强回波高度、降水强度的对应关系较差。利用北京地區5 min 間隔的自動氣象站降水觀測資料，SA 雷達觀測資料、FY-2衛星 TBB（Temperature of Black Body）資料、常規氣象探空資料和1°×1°NCEP／NCAR 最終分析資料，對2006—2013年髮生的10次極耑暴雨事件（14箇區（縣）中，任意一箇區縣代錶站24 h 內降水量≥100 mm，且暴雨區內至少有一箇自動氣象站降水彊度≥40 mm／h）的基本特徵進行瞭對比分析。結果錶明：（1）長生命週期的單體或多單體組織閤併的中呎度對流繫統（第Ⅰ類中呎度對流繫統）形成的暴雨中心一般位于北京西部山前地區或中心城區，這種分佈與低空偏東氣流的地形彊迫作用或城市彊迫作用有關；“列車效應”對應的多單體中呎度對流繫統（第Ⅱ類中呎度對流繫統）形成的極耑暴雨事件往往與兩次不同屬性的降水過程有關：鋒前暖區對流過程和鋒麵附近的對流過程。因此，降水分佈往往平行于低空急流軸或鋒麵。（2）第Ⅰ類中呎度對流繫統形成的極耑暴雨過程跼地性更彊，全市平均降水量遠小于暴雨量級（50 mm），其中，由混閤型降水主導的極耑暴雨事件一般是由幾乎不移動的長生命週期單體反複生消造成的，對流高度相對較低；而深對流主導的極耑暴雨事件一般由多單體組織、閤併、加彊造成，由于對流單體的上遲雲頂很高，最低 TBB 一般低于－55℃，這類極耑暴雨事件的短時彊降水具有顯著的間歇性：第一階段的彊降水與單體對流髮展過程對應，以後的短時彊降水與對流單體組織、閤併過程對應。（3）“列車效應”對應的多單體中呎度對流繫統暴雨過程，初始階段一般錶現為相互獨立的兩箇對流帶，即與鋒麵繫統對應的對流帶和與低空急流軸對應的暖區對流帶，隨著鋒麵對流帶逐漸嚮暖區對流帶移動，低空冷空氣逐漸侵入到暖區對流帶中，兩條對流雲帶逐漸閤併，對流活動進一步髮展；或者由于暖區對流帶截斷鋒麵對流帶的水汽入流，造成鋒麵對流減弱，而暖區對流帶組織性更彊，髮展更加旺盛。與第Ⅰ類中呎度對流繫統形成的極耑暴雨過程不同，這類暴雨過程往往造成全市平均降水量達到暴雨（≥50 mm）甚至大暴雨（≥100 mm）。（4）不同類型的極耑暴雨過程，大呎度水汽輸送條件不同：“列車效應”造成的暴雨過程多數情況下由源于孟加拉灣和源于西太平洋的兩支暖濕季風氣流共同構成，大呎度水汽供應充沛；而第Ⅰ類中呎度對流繫統中的混閤型降水造成的暴雨過程的水汽來源主要與低空東南氣流造成的近海水汽輸送有關；第Ⅰ類中呎度對流繫統中的深對流主導的深對流暴雨過程中整層水汽含量併不大，多數情況下水汽輸送僅齣現在對流層低層甚至僅在近地麵層內。（5）大多數情況下，無論哪類性質的極耑暴雨過程，在彊降水髮生時刻，雷達彊迴波高度一般在4 km 以下，僅有極箇彆時刻彊迴波中心高于5 km。極耑暴雨過程中，環境大氣對流有效位能（CAPE）的大小一般與對流髮展高度（雷達迴波頂高）具有較好的對應關繫，但與彊降水髮生時刻迴波彊度、最彊迴波高度、降水彊度的對應關繫較差。
이용북경지구5 min 간격적자동기상참강수관측자료，SA 뢰체관측자료、FY-2위성 TBB（Temperature of Black Body）자료、상규기상탐공자료화1°×1°NCEP／NCAR 최종분석자료，대2006—2013년발생적10차겁단폭우사건（14개구（현）중，임의일개구현대표참24 h 내강수량≥100 mm，차폭우구내지소유일개자동기상참강수강도≥40 mm／h）적기본특정진행료대비분석。결과표명：（1）장생명주기적단체혹다단체조직합병적중척도대류계통（제Ⅰ류중척도대류계통）형성적폭우중심일반위우북경서부산전지구혹중심성구，저충분포여저공편동기류적지형강박작용혹성시강박작용유관；“열차효응”대응적다단체중척도대류계통（제Ⅱ류중척도대류계통）형성적겁단폭우사건왕왕여량차불동속성적강수과정유관：봉전난구대류과정화봉면부근적대류과정。인차，강수분포왕왕평행우저공급류축혹봉면。（2）제Ⅰ류중척도대류계통형성적겁단폭우과정국지성경강，전시평균강수량원소우폭우량급（50 mm），기중，유혼합형강수주도적겁단폭우사건일반시유궤호불이동적장생명주기단체반복생소조성적，대류고도상대교저；이심대류주도적겁단폭우사건일반유다단체조직、합병、가강조성，유우대류단체적상충운정흔고，최저 TBB 일반저우－55℃，저류겁단폭우사건적단시강강수구유현저적간헐성：제일계단적강강수여단체대류발전과정대응，이후적단시강강수여대류단체조직、합병과정대응。（3）“열차효응”대응적다단체중척도대류계통폭우과정，초시계단일반표현위상호독립적량개대류대，즉여봉면계통대응적대류대화여저공급류축대응적난구대류대，수착봉면대류대축점향난구대류대이동，저공랭공기축점침입도난구대류대중，량조대류운대축점합병，대류활동진일보발전；혹자유우난구대류대절단봉면대류대적수기입류，조성봉면대류감약，이난구대류대조직성경강，발전경가왕성。여제Ⅰ류중척도대류계통형성적겁단폭우과정불동，저류폭우과정왕왕조성전시평균강수량체도폭우（≥50 mm）심지대폭우（≥100 mm）。（4）불동류형적겁단폭우과정，대척도수기수송조건불동：“열차효응”조성적폭우과정다수정황하유원우맹가랍만화원우서태평양적량지난습계풍기류공동구성，대척도수기공응충패；이제Ⅰ류중척도대류계통중적혼합형강수조성적폭우과정적수기래원주요여저공동남기류조성적근해수기수송유관；제Ⅰ류중척도대류계통중적심대류주도적심대류폭우과정중정층수기함량병불대，다수정황하수기수송부출현재대류층저층심지부재근지면층내。（5）대다수정황하，무론나류성질적겁단폭우과정，재강강수발생시각，뢰체강회파고도일반재4 km 이하，부유겁개별시각강회파중심고우5 km。겁단폭우과정중，배경대기대류유효위능（CAPE）적대소일반여대류발전고도（뢰체회파정고）구유교호적대응관계，단여강강수발생시각회파강도、최강회파고도、강수강도적대응관계교차。
This paper analyses the fundamental properties of 10 extreme severe rain events (the event is defined as its precipita-tion ≥ 100 mm/(24 h)at any representative weather station among the 14 Districts or Counties with the rain intensity ≥40 mm/h over at least one automatic weather station)during 2006-2013 in the Beijing region,based on the rainfall data per 5 min of automatic weather stations,the data series of SA radar,TBB (Temperature of Black Body)of FY-2,routine sounding and 1°×1°NCEP/NCAR final analysis.The investigation results show that the severe rain centers,formed from long periodic convective cells or MCS organized/amalgamated by multi cells (typeⅠ),are usually located before the mountain or central ur-ban areas,and the distribution feature is related to the terrain forcing caused by easterlies airflow under the lower layer or the urban forcing.However,the extreme severe rain events which are dominated by the Train Effect associated with MCS of multi cells (typeⅡ)are connected with two different properties of raining process:The convective activity happening on the warming area and the other near a front,so the rainfall distributions are frequently parallel to the axis of low level jets or fronts.The precipitation distributions of the extreme rain events caused by MCS of typeⅠare more localized,and each of their average pre-cipitation of the whole administrative area is much lower than 50 mm.One of them is led by mixed convection,and its extreme rainfall is usually caused by long periodic or hardly moving convective cells to be generated and dissipated repeatedly,with the convection height relatively low.However,the extreme rain events led by deep convection are usually caused by multi cells to develop,organize and combine,and the lowest TBB of this typical MCS is usually lower than -55℃ since convective cloud top develops high.Short-time strong rainfall of these extreme events is intermittent:the initial rainfall corresponds with convective cells developing,and the second period is connected to the process of their organizing and combining.This study indicates that typeⅡMCS (Train Effect)shows often the two independent convection zones in the first stage:One is connected with the front and the other is a warm convection zone related to a low level jet.When the front moves toward the warm convection zone,the cold air in the low layer passes into the warm convection area gradually,the two convection zones begin to amalgamate slowly into single one while convective activity becomes to flourish,or since convection in the warm side prevents inflow of vapor,the front convection zone becomes weaker and weaker,meanwhile,the warm convection develops with more blossoming and organ-izing.The MCS ,unlike MCS of typeⅠ,is usually to give rise to the city wide torrential rain (≥ 50 mm)even heavy rain-storm (≥ 100 mm).The large scale vapor conditions are obviously different among the various typical convective severe pre-cipitation processes.In most cases the vapor sources of the severe rain to be connected with Train Effect are related to two warmly moist monsoon flows:one originates from the Bay of Bengal and the other is from the western Pacific Ocean,so the large scale vapor supplies are abundant.However,the vapor of the severe precipitation led by mixed convection of the typeⅠMCS is connected principally with offshore southeasterly wind in the low level;the vapor of the typeⅠMCS dominated by deep convection exists mostly in the lower troposphere even only near the surface,and in most cases the total vapor content of large scale is much less than others.No matter which extreme severe rain events,the strongest radar echo heights are rarely higher than 5 km,in most cases are lower than 4 km during the heaviest rainfall.The CAPE levels of the ambient atmosphere have of-ten good relationship with convective heights (Top of Radar reflectivity),but correspondence among the ambient CAPE,mo-mentary convection intensity and level of the strongest reflectivity or the maximum rainfall intensity is completely heterogene-ous.