气候与环境研究
氣候與環境研究
기후여배경연구
CLIMATIC AND ENVIRONMENTAL RESEARCH
2014年
3期
311-320
,共10页
肖科丽%王娜%魏娜%王越%肖舜
肖科麗%王娜%魏娜%王越%肖舜
초과려%왕나%위나%왕월%초순
极端降水%环流形势%年代际变化%海温异常
極耑降水%環流形勢%年代際變化%海溫異常
겁단강수%배류형세%년대제변화%해온이상
Extreme precipitation%Circulation pattern%Interdecadal variation%Sea surface temperature anomaly
利用NCEP /NCAR再分析资料,对陕西省2010年盛夏极端多雨的形成机理进行了个例分析研究。结果表明:2010年盛夏极端多雨的主要成因是大尺度环流形势异常及海温异常等多种因素综合作用的结果。在500 hPa高度场上欧亚中高纬区为“两脊一槽”型分布,乌拉尔山阻塞高压与咸海到巴尔喀什湖的低压槽稳定维持,低槽分裂冷空气沿中纬度西风带东移,与西太平洋副热带高压外围西北侧暖湿气流在陕西上空相汇,是造成2010年陕西盛夏极端多雨的直接原因。来自南海的水汽输送在850 hPa、700 hPa上表现都很显著,来自孟加拉湾的水汽只有850 hPa表现明显。La Ni?a事件当年陕西盛夏降水易偏多利于出现极端降水。盛夏降水量年代际变化特征显示,陕西中部和南部2010年处于一个年代际的多雨期内,出现极端降水的可能性增大。
利用NCEP /NCAR再分析資料,對陝西省2010年盛夏極耑多雨的形成機理進行瞭箇例分析研究。結果錶明:2010年盛夏極耑多雨的主要成因是大呎度環流形勢異常及海溫異常等多種因素綜閤作用的結果。在500 hPa高度場上歐亞中高緯區為“兩脊一槽”型分佈,烏拉爾山阻塞高壓與鹹海到巴爾喀什湖的低壓槽穩定維持,低槽分裂冷空氣沿中緯度西風帶東移,與西太平洋副熱帶高壓外圍西北側暖濕氣流在陝西上空相彙,是造成2010年陝西盛夏極耑多雨的直接原因。來自南海的水汽輸送在850 hPa、700 hPa上錶現都很顯著,來自孟加拉灣的水汽隻有850 hPa錶現明顯。La Ni?a事件噹年陝西盛夏降水易偏多利于齣現極耑降水。盛夏降水量年代際變化特徵顯示,陝西中部和南部2010年處于一箇年代際的多雨期內,齣現極耑降水的可能性增大。
이용NCEP /NCAR재분석자료,대합서성2010년성하겁단다우적형성궤리진행료개례분석연구。결과표명:2010년성하겁단다우적주요성인시대척도배류형세이상급해온이상등다충인소종합작용적결과。재500 hPa고도장상구아중고위구위“량척일조”형분포,오랍이산조새고압여함해도파이객십호적저압조은정유지,저조분렬랭공기연중위도서풍대동이,여서태평양부열대고압외위서북측난습기류재협서상공상회,시조성2010년협서성하겁단다우적직접원인。래자남해적수기수송재850 hPa、700 hPa상표현도흔현저,래자맹가랍만적수기지유850 hPa표현명현。La Ni?a사건당년협서성하강수역편다리우출현겁단강수。성하강수량년대제변화특정현시,협서중부화남부2010년처우일개년대제적다우기내,출현겁단강수적가능성증대。
Based on analyzed NCEP/NCAR data, the mechanisms for extreme rain events during the midsummer of 2010 has been investigated. The results show an abnormal general circulation caused mainly by the sea surface temperature. There is a two ridges and one trough circulation pattern above mid-high latitude at 500 hPa, where the Eurasia and the Ural blocking highs and the low between the Aral Sea and Lake Balkhash were kept stable, and the small trough split from the low migrated eastwards along the westerly in mid-latitude Asia, converging with warm humid air masses from the northwest edge of the west Pacific subtropical high above Shaanxi. These factors directly resulted in extremely rainy weather during the high summer of 2010. The greater amounts of water vapor from the periphery of the Arabian Sea, the highs in the South China Sea and the western Pacific subtropics transported to Shaanxi at 850 hPa, and the formation of a strong cyclonic convergence zone in Shaanxi and its upstream region were all very conducive to the occurrence and continuation of extreme precipitation. At 700 hPa, two clear vapor conveyor belts and, upstream of Shaanxi, a generating and developing southwest vortex (the main system causing the rainstorm in Shaanxi) occurred. Decadal variations in precipitation during high summer also indicated that after 2010 Shaanxi was in a decadal period during which the possibility of extremely rainy weather was quite great. Further, during La Ni?a event years, the high summer in Shaanxi also favours extremely rainy weather.