气象与环境学报
氣象與環境學報
기상여배경학보
JOURNAL OF METEOROLOGY AND ENVIRONMENT
2014年
1期
8-14
,共7页
中尺度对流云团%雷暴%低空风切变
中呎度對流雲糰%雷暴%低空風切變
중척도대류운단%뇌폭%저공풍절변
Mesoscale convective cloud cluster%Thunderstorm%Low-level wind shear
利用NCEP格点资料模拟2011年8月21日沈阳地区的冰雹天气过程,结合机场自动观测数据、多普勒雷达资料和卫星云图等分析冰雹的形成机制。结果表明:此次冰雹天气是由冷涡内部的中尺度涡旋引起的,卫星云图上的中尺度云团是中尺度涡旋的产物;0℃等温线位于600 hPa,-20℃位于450 hPa附近,两者之间厚度为2 km左右;冰雹发生前,斜升气流的最大上升速度为20 m·s-1以上,水分累积区位于0℃层以上,保证了水分累积区均由过冷水滴组成;高层干冷空气倾斜下侵到中低层的暖湿空气中,对强对流的发生发展起到了至关重要的作用;低层MPV1为强对流提供对流不稳定机制,中层MPV2为强对流提供了对称不稳定机制,高层两种不稳定共存,均为对流发展贡献力量;对流有效位能积累和释放随时间的演变对冰雹的出现有一定的指示意义;10:30多普勒雷达图显示回波强度随高度增强,速度图上存在西南低空急流,有利于对流的发展。
利用NCEP格點資料模擬2011年8月21日瀋暘地區的冰雹天氣過程,結閤機場自動觀測數據、多普勒雷達資料和衛星雲圖等分析冰雹的形成機製。結果錶明:此次冰雹天氣是由冷渦內部的中呎度渦鏇引起的,衛星雲圖上的中呎度雲糰是中呎度渦鏇的產物;0℃等溫線位于600 hPa,-20℃位于450 hPa附近,兩者之間厚度為2 km左右;冰雹髮生前,斜升氣流的最大上升速度為20 m·s-1以上,水分纍積區位于0℃層以上,保證瞭水分纍積區均由過冷水滴組成;高層榦冷空氣傾斜下侵到中低層的暖濕空氣中,對彊對流的髮生髮展起到瞭至關重要的作用;低層MPV1為彊對流提供對流不穩定機製,中層MPV2為彊對流提供瞭對稱不穩定機製,高層兩種不穩定共存,均為對流髮展貢獻力量;對流有效位能積纍和釋放隨時間的縯變對冰雹的齣現有一定的指示意義;10:30多普勒雷達圖顯示迴波彊度隨高度增彊,速度圖上存在西南低空急流,有利于對流的髮展。
이용NCEP격점자료모의2011년8월21일침양지구적빙박천기과정,결합궤장자동관측수거、다보륵뢰체자료화위성운도등분석빙박적형성궤제。결과표명:차차빙박천기시유랭와내부적중척도와선인기적,위성운도상적중척도운단시중척도와선적산물;0℃등온선위우600 hPa,-20℃위우450 hPa부근,량자지간후도위2 km좌우;빙박발생전,사승기류적최대상승속도위20 m·s-1이상,수분루적구위우0℃층이상,보증료수분루적구균유과랭수적조성;고층간랭공기경사하침도중저층적난습공기중,대강대류적발생발전기도료지관중요적작용;저층MPV1위강대류제공대류불은정궤제,중층MPV2위강대류제공료대칭불은정궤제,고층량충불은정공존,균위대류발전공헌역량;대류유효위능적루화석방수시간적연변대빙박적출현유일정적지시의의;10:30다보륵뢰체도현시회파강도수고도증강,속도도상존재서남저공급류,유리우대류적발전。
Based on the NCEP grid data,a hail weather process on August 21,2011 in Shenyang region was simu-lated and its formation mechanism was analyzed using the automatic observation data collected at the airport, Doppler radar data and satellite image.The results show that the hail weather is caused by mesoscale vortex of cold vortex over northeastern China,so is mesoscale cloud cluster on the satellite cloud images.The 0 ℃and -20 ℃i-sothermal lines are located in 600 hPa and near 450 hPa,respectively,and the thickness between them is about 2 km.Before the hail occurs,the maximum ascending speed of obliquely ascending airflow is more than 20 m·s-1 and water vapor accumulation region is located in the layer above 0 ℃,which ensures that the water accumulated area consists of super cooled water droplet.The upper dry cold air invades into the warm-wet air of middle-low level,which is important to convective occurrence and development.The MPV1 in the low level provides the con-vective instability mechanism for strong convection;the MPV2 in the middle level is for symmetric instability mechanism;two unstable mechanisms coexist in the high level and both contribute to the development of convec-tion.The evolution of convective available potential energy accumulation and release with the time is indicative to hail.At 10:30,the echo intensity increases with the height on Doppler radar map.There is southwest low level jet on the velocity map.Both are favorable to the development of convective.