中亚低涡背景下中天山地区一次短时强降水过程中尺度特征
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摘要
利用常规气象观测资料、区域自动气象站观测资料及卫星、多普勒天气雷达、风廓线等非常规探测资料和美国气象环境预报中心(National Centers for Environmental Prediction,NCEP)逐日4次的1°×1°再分析资料,对2015年6月27—28日中天山地区一次短时强降水过程的中尺度对流条件和对流系统特征进行分析。结果表明:此次中天山地区强降水天气过程是中亚低涡前部的东北—西南向气旋式切变和深厚的西南暖湿气流共同作用引发的,低层切变和气旋式辐合的动力抬升、地面中尺度辐合线是此次强对流天气的直接触发因子。里海和咸海南侧的水汽沿着中亚低涡底部的偏西气流和前部的西南气流输送至强降水区,为此次短时强降水过程提供了充沛的水汽条件。大气可降水量的跃变和风廓线产品的垂直变化特征与短时强降水的开始、加强及减弱具有较好的对应关系;红外云图反映了中天山地区短时强降水发生在对流云团云顶亮温(Temperature of Black Body,TBB)梯度最大处;短时强降水由低质心和高效率的降水回波造成的,降水强度与回波顶高度存在较好的正相关关系。
Using the data from conventional and automatic weather stations,Doppler radar, satellite and wind-profiler radar as well as the associated NCEP( National Centers for Environmental Prediction) reanalysis,we analyzed the convective conditions and mesoscale characteristics of a short-time heavy rainfall in the middle Tianshan area on June 27-28,2015. The results indicate that this strong convective weather process is caused by the interaction of the northeast to southwest anticyclonic shear in front of the central Asian vortex and the deep warm-wet flow coming from southwest. The direct impact systems to this process are convective instability, including the dynamic lifting condition, shear line in the lower troposphere, surface mesoscale convergence line and the cyclone type convergence center. The convergence of water vapor at the bottom of the central Asian vortex along west and that in front of the central Asian vortex along southwest attributes a favorable vapor condition to this process. Analysis shows that the abrupt variation of GPS-PWV( Global Position System,Precipitable Water Vapor) and vertical variation of wind from wind-profiler radar have a good correspondence to the beginning, strengthening and ending of the precipitation. Satellite IR imagery shows that the short-time strong rainfall occurs at the maximum gradient area of the brightness temperature of convective clouds and is identified by the low centroid and the high-efficiency precipitation echoes. The precipitation intensity is positively correlated with the height of echo top.
Using the data from conventional and automatic weather stations,Doppler radar, satellite and wind-profiler radar as well as the associated NCEP( National Centers for Environmental Prediction) reanalysis,we analyzed the convective conditions and mesoscale characteristics of a short-time heavy rainfall in the middle Tianshan area on June 27-28,2015. The results indicate that this strong convective weather process is caused by the interaction of the northeast to southwest anticyclonic shear in front of the central Asian vortex and the deep warm-wet flow coming from southwest. The direct impact systems to this process are convective instability, including the dynamic lifting condition, shear line in the lower troposphere, surface mesoscale convergence line and the cyclone type convergence center. The convergence of water vapor at the bottom of the central Asian vortex along west and that in front of the central Asian vortex along southwest attributes a favorable vapor condition to this process. Analysis shows that the abrupt variation of GPS-PWV( Global Position System,Precipitable Water Vapor) and vertical variation of wind from wind-profiler radar have a good correspondence to the beginning, strengthening and ending of the precipitation. Satellite IR imagery shows that the short-time strong rainfall occurs at the maximum gradient area of the brightness temperature of convective clouds and is identified by the low centroid and the high-efficiency precipitation echoes. The precipitation intensity is positively correlated with the height of echo top.
引文
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[15]李崇,吉曹翔,夏传栋,等.沈阳地区强对流天气潜势预报环境参数特征分析[J].气象与环境学报,2016,32(6):43-51.
[16]牛淑贞,张一平,梁俊平,等.郑州市两次短时强降水过程的环境条件和中尺度特征对比[J].暴雨灾害,2016,35(2):138-147.
[17]王囝囝,黄振,邹善勇,等.大连地区短时强降水天气特征及预报指标研究[J].气象与环境学报,2016,32(4):32-38.
[18]艾永智,杨传荣,李蕊.玉溪一次强对流天气的中尺度特征分析[J].高原气象,2015,34(5):1391-1401.
[19]方翀,毛冬艳,张小雯,等.2012年7月21日北京地区特大暴雨中尺度对流条件和特征初步分析[J].气象,2012,38(10):1278-1287.
[2]张家宝,邓子风.新疆降水概论[M].北京:气象出版社,1987:400.
[3]杨莲梅,张云惠,秦贺,等.中亚低涡研究若干进展及问题[J].沙漠与绿洲气象,2015,9(5):1-8.
[4]江远安,包斌,王旭.南疆西部大降水天气过程的统计分析[J].新疆气象,2001,24(5):19-20.
[5]张云惠,杨莲梅,肖开提·多莱特,等.1971—2010年中亚低涡活动特征[J].应用气象学报,2012,23(3):312-321.
[6]李如琦,李建刚,唐冶,等.中亚低涡引发的两次南疆西部暴雨中尺度特征对比分析[J].干旱气象,2016,34(2):297-304.
[7]李圆圆,肖开提·多莱特,杨莲梅,等.一次中亚低涡造成的新疆暴雪天气过程分析[J].气象科学,2014,34(3):299-304.
[8]李改琴,杜丽娅,赵海青,等.豫北一次强降水过程的多尺度诊断[J].干旱气象,2016,34(5):828-835.
[9]曾波,谌芸,李泽椿.中国中东部地区夏季中尺度对流系统发生前环境场特征[J].高原气象,2016,35(2):460-468.
[10]李大为,梁红,贾冬婵,等.“20110714”沈阳短时强降水多普勒雷达回波特征[J].气象与环境学报,2013,29(2):75-80.
[11]张晰莹,徐玥.一次夏季低涡系统中MCS演变特征[J].气象与环境学报,2013,29(2):1-5.
[12]俞小鼎.短时强降水临近预报的思路与方法[J].暴雨灾害,2013,32(3):202-209.
[13]孙继松,陶祖钰.强对流天气分析与预报中的若干基本问题[J].气象,2012,38(2):164-173.
[14]樊李苗,俞小鼎.中国短时强对流天气的若干环境参数特征分析[J].高原气象,2013,32(1):156-165.
[15]李崇,吉曹翔,夏传栋,等.沈阳地区强对流天气潜势预报环境参数特征分析[J].气象与环境学报,2016,32(6):43-51.
[16]牛淑贞,张一平,梁俊平,等.郑州市两次短时强降水过程的环境条件和中尺度特征对比[J].暴雨灾害,2016,35(2):138-147.
[17]王囝囝,黄振,邹善勇,等.大连地区短时强降水天气特征及预报指标研究[J].气象与环境学报,2016,32(4):32-38.
[18]艾永智,杨传荣,李蕊.玉溪一次强对流天气的中尺度特征分析[J].高原气象,2015,34(5):1391-1401.
[19]方翀,毛冬艳,张小雯,等.2012年7月21日北京地区特大暴雨中尺度对流条件和特征初步分析[J].气象,2012,38(10):1278-1287.