暴雨灾害
暴雨災害
폭우재해
TORRENTIAL RAIN AND DISASTERS
2011年
3期
227-233
,共7页
卢卫垦%叶子祥%庄千宝%余贞寿
盧衛墾%葉子祥%莊韆寶%餘貞壽
로위은%협자상%장천보%여정수
暴雨%低空东南风急流%超地转%地转平衡
暴雨%低空東南風急流%超地轉%地轉平衡
폭우%저공동남풍급류%초지전%지전평형
heavy rain%southeasterly low-level jet%supergeostrophy%geostrophic balance
利用NCEP再分析资料、气象卫星云图资料、自动气象站监测网资料,对浙江中南部沿海2010年7月24-26日大暴雨过程和同年9月20日暴雨过程进行对比分析。结果表明:两次暴雨过程均伴有低空东南风急流,但前者浙江中南沿海地区出现大暴雨、局部特大暴雨,低层具有明显超地转特征,由局地生成的β中尺度对流云团引发;后者同一地区仅出现大雨到暴雨,边界层无明显超地转风出现,其发生与登陆台风带来的弱降水云系有关。在边界层风速急增、超地转最强的时段内,容易发生大暴雨或特大暴雨;超地转风发生时,由于地形作用及边界层摩擦效应,低层风垂直切变和海陆风速切变明显加强;若边界层风速处于地转平衡状态,则不利于大暴雨发生。
利用NCEP再分析資料、氣象衛星雲圖資料、自動氣象站鑑測網資料,對浙江中南部沿海2010年7月24-26日大暴雨過程和同年9月20日暴雨過程進行對比分析。結果錶明:兩次暴雨過程均伴有低空東南風急流,但前者浙江中南沿海地區齣現大暴雨、跼部特大暴雨,低層具有明顯超地轉特徵,由跼地生成的β中呎度對流雲糰引髮;後者同一地區僅齣現大雨到暴雨,邊界層無明顯超地轉風齣現,其髮生與登陸檯風帶來的弱降水雲繫有關。在邊界層風速急增、超地轉最彊的時段內,容易髮生大暴雨或特大暴雨;超地轉風髮生時,由于地形作用及邊界層摩抆效應,低層風垂直切變和海陸風速切變明顯加彊;若邊界層風速處于地轉平衡狀態,則不利于大暴雨髮生。
이용NCEP재분석자료、기상위성운도자료、자동기상참감측망자료,대절강중남부연해2010년7월24-26일대폭우과정화동년9월20일폭우과정진행대비분석。결과표명:량차폭우과정균반유저공동남풍급류,단전자절강중남연해지구출현대폭우、국부특대폭우,저층구유명현초지전특정,유국지생성적β중척도대류운단인발;후자동일지구부출현대우도폭우,변계층무명현초지전풍출현,기발생여등륙태풍대래적약강수운계유관。재변계층풍속급증、초지전최강적시단내,용역발생대폭우혹특대폭우;초지전풍발생시,유우지형작용급변계층마찰효응,저층풍수직절변화해륙풍속절변명현가강;약변계층풍속처우지전평형상태,칙불리우대폭우발생。
The comparative analysis on the extra heavy rain case during 24—26 July of 2010 and the heavy rain case on 22 September 2010 at the middle and southern coast area of Zhejiang were studied by using NCEP reanalysis data,satellite images and observations of automatic weather station.The conclusions are drawn that two heavy rain cases given above are all followed by southeasterly low-level jet.The extra heavy rain(excessive heavy rain in some areas) occurred in the middle and southern coast area of Zhejiang is triggered by meso-β-scale convective clusters which originated locally,and there are obvious supergeostrophic features in low-level in the case.The heavy rain occurred in the above coast area is related to the weak precipitation nephsystem brought by landed typhoon,and there is not obvious supergeostrophic wind in boundary layer in the case.Extra(or excessive) heavy rain is generated easily when the wind speed in boundary layer increases rapidly and the supergeostrophic wind becomes the strongest.When the supergeostrophic wind appeared,the joint function of topographic forcing effect and frictional effect in the boundary layer leads to the obvious reinforcement of vertical wind shear in low-level and sea-land breeze shear.It is unfavorable to the formation of extra heavy rain that the wind speed is in geostrophic balance in boundary layer.