暴雨灾害
暴雨災害
폭우재해
TORRENTIAL RAIN AND DISASTERS
2014年
2期
156-162
,共7页
台风暴雨%水汽辐合%中尺度滤波%湿位涡
檯風暴雨%水汽輻閤%中呎度濾波%濕位渦
태풍폭우%수기복합%중척도려파%습위와
heavy rain caused by typhoon%water vapor convergence%mesoscale filter%moist potential vorticity
利用多普勒天气雷达、地面加密观测资料及NCEP格点再分析资料，从低层环境场、雷达回波特征、湿位涡分布等方面，对比分析路径相似的“启德”(1213号)和“纳沙”(1117号)台风造成广西降水条件的差异。结果表明：“启德”东侧的东南风急流强，水汽强辐合中心偏于台风中心附近，降水强度大，而“纳沙”水汽辐合主要位于东北气流与东南气流的汇合区，降水范围大；两者在越南北部登陆后其后部均存在窄长带状的中尺度强回波特征，但“纳沙”的螺旋回波雨带伸展范围更宽、持续时间更长“；纳沙”因有冷空气侵入，近地面层气流出现多个分支，更有利于形成中尺度涡旋和气流汇合带，是其比“启德”产生较大范围强降水的重要因素；两者的降水分布与低层湿位涡负值区有较好对应关系，强降水落区主要位于湿正压项(VMPV1)负值区和斜压项(VMPV2)正值区相叠加的区域，而“启德”的VMPV1负值比“纳沙”小，其对应的降水强度也较大。
利用多普勒天氣雷達、地麵加密觀測資料及NCEP格點再分析資料，從低層環境場、雷達迴波特徵、濕位渦分佈等方麵，對比分析路徑相似的“啟德”(1213號)和“納沙”(1117號)檯風造成廣西降水條件的差異。結果錶明：“啟德”東側的東南風急流彊，水汽彊輻閤中心偏于檯風中心附近，降水彊度大，而“納沙”水汽輻閤主要位于東北氣流與東南氣流的彙閤區，降水範圍大；兩者在越南北部登陸後其後部均存在窄長帶狀的中呎度彊迴波特徵，但“納沙”的螺鏇迴波雨帶伸展範圍更寬、持續時間更長“；納沙”因有冷空氣侵入，近地麵層氣流齣現多箇分支，更有利于形成中呎度渦鏇和氣流彙閤帶，是其比“啟德”產生較大範圍彊降水的重要因素；兩者的降水分佈與低層濕位渦負值區有較好對應關繫，彊降水落區主要位于濕正壓項(VMPV1)負值區和斜壓項(VMPV2)正值區相疊加的區域，而“啟德”的VMPV1負值比“納沙”小，其對應的降水彊度也較大。
이용다보륵천기뢰체、지면가밀관측자료급NCEP격점재분석자료，종저층배경장、뢰체회파특정、습위와분포등방면，대비분석로경상사적“계덕”(1213호)화“납사”(1117호)태풍조성엄서강수조건적차이。결과표명：“계덕”동측적동남풍급류강，수기강복합중심편우태풍중심부근，강수강도대，이“납사”수기복합주요위우동북기류여동남기류적회합구，강수범위대；량자재월남북부등륙후기후부균존재착장대상적중척도강회파특정，단“납사”적라선회파우대신전범위경관、지속시간경장“；납사”인유랭공기침입，근지면층기류출현다개분지，경유리우형성중척도와선화기류회합대，시기비“계덕”산생교대범위강강수적중요인소；량자적강수분포여저층습위와부치구유교호대응관계，강강수락구주요위우습정압항(VMPV1)부치구화사압항(VMPV2)정치구상첩가적구역，이“계덕”적VMPV1부치비“납사”소，기대응적강수강도야교대。
Using data from Doppler weather radar, intensive automatic weather stations and NCEP reanalysis , we have analyzed the differ-ences of environmental conditions in producing rainfalls in Guangxi by typhoon Kai-tak (1213) and Nesat (1117), which had similar tracks, focusing on their low-level environment fields, radar reflectivity and contribution of moist potential vorticity (MPV) etc. Results show that there is a strong southeasterly jet on the east side of Kai-tak, and a strong moist convergence center tends to be around the typhoon center where there is the intense rainfall, while the moisture convergence zone formed by typhoon Nesat mainly locates in the area where northeaster-ly was met by southeasterly, and rain fell in a broader area. There is a narrow and long strong mesoscale radar echo band in the back of ty-phoon Kai-tak and Nesat after they made landfall the northern Viet Nam. Although the spiral rain band around Nesat stretched over a wider range and lasted for a longer period. There were the multiple airflow branches near the ground around Nesat because of the intrusion of cold air that is more favorable to the formation of mesoscale vortex and airflow convergence zone, which is believed to be the main reason that leads to a broader area of severe precipitation in Nesat than in Kai-tak. The rain area induced by two typhoons well corresponds to the negative val-ue centers of MPV. Their severe precipitation centers are situated where negative moist barotropc term VMPV1 is overlapped by positive baro-clinic term VMPV2. Since the negative VMPV1 value in the rain zone generated by Kai-tak is smaller than that by Nesat, the rainfall caused by Kai-tak is stronger than that by Nesat.
