气象与环境科学
氣象與環境科學
기상여배경과학
METEOROLOGICAL AND ENVIRONMENTAL SCIENCES
2011年
4期
31-39
,共9页
马月枝%王新红%宋培玲%王兵
馬月枝%王新紅%宋培玲%王兵
마월지%왕신홍%송배령%왕병
强降水%副高%垂直螺旋度%干冷空气侵入%中β云团
彊降水%副高%垂直螺鏇度%榦冷空氣侵入%中β雲糰
강강수%부고%수직라선도%간랭공기침입%중β운단
heavy rainstorm%subtropical high%vertical helicity%dry cold air intrusion%meso- β cloud
利用常规观测资料、卫星云图和NCEP全球分析资料(FNL),对2010年8月13日豫北沿黄地区出现的短时强降水过程进行了诊断分析。结果表明:这次强降水过程是在低槽东移、副高东退南压的形势下,由高、低空急流,中低层切变线,以及地面倒槽和弱冷空气等影响系统共同作用造成的。强降水发生时暴雨区低层水汽辐合跃增,配合强劲的垂直上升运动,在暴雨区上空建立深厚的湿层。过程前期的副高控制为强降水的发生积聚了大量的不稳定能量,强降水区正好位于低层能量锋区的南侧,同时CAPE值的锐减时段对应着最强降水时段。低层弱的干冷空气侵入是本次暴雨过程产生的重要触发机制,高层干冷空气的侵入有利于干层的形成和维持,干层的存在加强了对流不稳定性,对暴雨的加强和发展起重要作用。强降水过程中低层正的垂直螺旋度演变趋势与强降水的落区和降水强度变化有较好的对应关系。垂直螺旋度中低层正中心、高层负中心,这种上下耦合的结构特点对系统自身的发展及暴雨的维持十分有利。
利用常規觀測資料、衛星雲圖和NCEP全毬分析資料(FNL),對2010年8月13日豫北沿黃地區齣現的短時彊降水過程進行瞭診斷分析。結果錶明:這次彊降水過程是在低槽東移、副高東退南壓的形勢下,由高、低空急流,中低層切變線,以及地麵倒槽和弱冷空氣等影響繫統共同作用造成的。彊降水髮生時暴雨區低層水汽輻閤躍增,配閤彊勁的垂直上升運動,在暴雨區上空建立深厚的濕層。過程前期的副高控製為彊降水的髮生積聚瞭大量的不穩定能量,彊降水區正好位于低層能量鋒區的南側,同時CAPE值的銳減時段對應著最彊降水時段。低層弱的榦冷空氣侵入是本次暴雨過程產生的重要觸髮機製,高層榦冷空氣的侵入有利于榦層的形成和維持,榦層的存在加彊瞭對流不穩定性,對暴雨的加彊和髮展起重要作用。彊降水過程中低層正的垂直螺鏇度縯變趨勢與彊降水的落區和降水彊度變化有較好的對應關繫。垂直螺鏇度中低層正中心、高層負中心,這種上下耦閤的結構特點對繫統自身的髮展及暴雨的維持十分有利。
이용상규관측자료、위성운도화NCEP전구분석자료(FNL),대2010년8월13일예북연황지구출현적단시강강수과정진행료진단분석。결과표명:저차강강수과정시재저조동이、부고동퇴남압적형세하,유고、저공급류,중저층절변선,이급지면도조화약랭공기등영향계통공동작용조성적。강강수발생시폭우구저층수기복합약증,배합강경적수직상승운동,재폭우구상공건립심후적습층。과정전기적부고공제위강강수적발생적취료대량적불은정능량,강강수구정호위우저층능량봉구적남측,동시CAPE치적예감시단대응착최강강수시단。저층약적간랭공기침입시본차폭우과정산생적중요촉발궤제,고층간랭공기적침입유리우간층적형성화유지,간층적존재가강료대류불은정성,대폭우적가강화발전기중요작용。강강수과정중저층정적수직라선도연변추세여강강수적락구화강수강도변화유교호적대응관계。수직라선도중저층정중심、고층부중심,저충상하우합적결구특점대계통자신적발전급폭우적유지십분유리。
By using routine observational data, satellite cloud image and the FNL data of NCEP, the rainstorm event over northern Henan along the Yellow River on 13 August 2010 is analyzed. The result shows that the heavy rains is affected directly by the Western Pacific Subtropical High(WPSH) when it interacts with mid-latitude though in addition to upper and lower-level jets, the shear line of middle and lower layer, ground though, and invasion of weak cold air. In heavy rain area the lower water vapor rapidly jump as the heavy rain happens. With the strong vertical ascending motion the deep moisture layer is established over the heavy rain area. Before the event plenty of instability energy has been accumulated for the control of the subtropical high and the heavy rain area is located just south of energy frontal zone of low layer. The plummeted time of CAPE value corresponds to heavy rainfall time. Weak dry cold air from the north at the low layer is the important trigger mechanism of the heavy rain. The invasion of dry cold air at upper layer is useful to the formation and maintenance of dried air layer which strengthens the con- vection instability and plays an important role in the strength and development of the heavy rain. During the heavy rainfall the variation trend of positive vertical helieity of mid-low layers has a good corresponding relationship with heavy rain area and precipitation intensity. The allocation of positive center at the mid-low layers and negative center at the upper layers is useful to the development of the system and the continuation of heavy rain.