干旱气象
榦旱氣象
간한기상
GANSU METEOROLOGY
2011年
4期
478-482
,共5页
罕见降雪%低温%天气气候分析
罕見降雪%低溫%天氣氣候分析
한견강설%저온%천기기후분석
the rare snowfall%low temperature%synoptic and climatic analysis
2008年1月中下旬位于西北地区东部的陇东黄土高原出现近60 a罕见阴雪低温天气,利用NCEP/NCAR大气环流资料分析了环流背景和物理量特征。结果表明:西伯利亚脊强盛,青藏高原西部低槽和中国东部弱脊维持,东亚大槽偏北,青藏高原南支气流强,控制中亚、中国北方大部和西北地区的冷气团强盛活跃,500 hPa和700 hPa西北地区东部为负距平,700 hPa降温强。700 hPa相对湿度西北地区东部处于正距平中心,500 hPa相对湿度也在70%以上。700 hPa风场在98°~110°E、35°~40°N存在明显的切变,水汽通量和散度分析表明,降雪期间低层存在水汽输送和辐合。主要降雪时段700~500 hPa散度场表现为辐合,200 hPa表现为辐散;700~200 hPa涡度场表现为正涡度区,在降雪过程中有弱的动力抬升作用,降雪强度大。
2008年1月中下旬位于西北地區東部的隴東黃土高原齣現近60 a罕見陰雪低溫天氣,利用NCEP/NCAR大氣環流資料分析瞭環流揹景和物理量特徵。結果錶明:西伯利亞脊彊盛,青藏高原西部低槽和中國東部弱脊維持,東亞大槽偏北,青藏高原南支氣流彊,控製中亞、中國北方大部和西北地區的冷氣糰彊盛活躍,500 hPa和700 hPa西北地區東部為負距平,700 hPa降溫彊。700 hPa相對濕度西北地區東部處于正距平中心,500 hPa相對濕度也在70%以上。700 hPa風場在98°~110°E、35°~40°N存在明顯的切變,水汽通量和散度分析錶明,降雪期間低層存在水汽輸送和輻閤。主要降雪時段700~500 hPa散度場錶現為輻閤,200 hPa錶現為輻散;700~200 hPa渦度場錶現為正渦度區,在降雪過程中有弱的動力抬升作用,降雪彊度大。
2008년1월중하순위우서북지구동부적롱동황토고원출현근60 a한견음설저온천기,이용NCEP/NCAR대기배류자료분석료배류배경화물리량특정。결과표명:서백리아척강성,청장고원서부저조화중국동부약척유지,동아대조편북,청장고원남지기류강,공제중아、중국북방대부화서북지구적랭기단강성활약,500 hPa화700 hPa서북지구동부위부거평,700 hPa강온강。700 hPa상대습도서북지구동부처우정거평중심,500 hPa상대습도야재70%이상。700 hPa풍장재98°~110°E、35°~40°N존재명현적절변,수기통량화산도분석표명,강설기간저층존재수기수송화복합。주요강설시단700~500 hPa산도장표현위복합,200 hPa표현위복산;700~200 hPa와도장표현위정와도구,재강설과정중유약적동력태승작용,강설강도대。
By using NCEP/NCAR data,this paper analyzed the circulation background and the physical quantity characteristic of the rare snowy and low temperature weather event occurred on January 10 to 31 in 2008 in eastern region of Gansu province.The results indicated that during this weather process,the Siberia ridge was powerful,the trough in the west Qinghai-Tibet Plateau and the weak ridge in East China persisted,with the abnormally northerly location of East Asian trough and the strong south branch jet stream in Qinghai-Tibet plateau,the cold air mass was active which controlled the middle of Asia and the North China and Northwest China.The temperature at the level of 700 hPa decreased strongly.The center of 700 hPa relative humidity positive anomaly was located in the eastern of Northwest China,and 500 hPa relative humidity was more than 70%.The 700 hPa wind had obvious shear in the range of 98°-110°E and 35°-40°N.There was transfer and convergence of moisture at the lower level during the period of snow falling,but smaller than that of autumn precipitation.The vorticity was positive from700 to 200 hPa.