摘要
利用多普勒雷达探测资料和NCEP再分析资料,对2003—2010年发生在江淮地区的6个龙卷超级单体风暴及其环境参数进行了分析。研究表明:(1)龙卷超级单体风暴H_(BASE)平均为1.7 km,H_(TOP)平均为9.1 km;H多在风暴的下部,近于下部的1/4处。H_(BASE)平均值比江淮地区各种超级单体的平均值低得多,H_(TOP)则略低。(2)龙卷超级单体I_(VIL)平均为25.6 kg/m^2,Z_(MX)平均为54.8 dBz。和江淮地区超级单体相比,龙卷I_(VIL)要小得多,而龙卷Z_(MX)略低。(3)龙卷超级单体的中气旋M_(BASE)、M_(TOP)和M_(SHR)平均值分别为1.2 km、3.9 km和14.4×10^(-3)s^(-1),和江淮地区超级单体相比,龙卷M_(BASE、M_(TOP)明显低,而M_(SHR)略高。(4)TVS参数最强时的VAD在12—45 m/s,V_(LLD)多大于30 m/s,V_(MXD)多超过30 m/s,V_(MXD)的高度不低于0.8 km,T_(DPT),在2.4—6.4 km,T_(BASE)在0.7—1.5 km,T_(TOP)在2.3—6.4 km,T_(MXSHR)超过22×10^(-3)s^(-1)。TVS参数最强时间与龙卷实际时间基本吻合,平均相差4.2 min;平均而言,TVS出现后6 min有龙卷发生。(5)雷达推算的龙卷超级单体的0—6 km风垂直切变比江淮地区超级单体的风垂直切变平均值高15.2%;龙卷发生前ICAPE平均为1752 J/kg,I_k为38℃,850 hPa到地面风切变平均超过12 m/s,850—500 hPa温差平均为23.7℃。龙卷发生前能量处在中等到强的状态,大气不稳定性较强,风垂直切变大。
Based on the Doppler radar detection data and the NCEP reanalysis data,6 tornado supercell storms in the Yangtze-Huaihe region from 2003 to 2010 and their environmental parameters were analyzed.The results show that：（1）H BASE average of the tornado supercell storms was 1.7 km,H TOP average was 9.1 km.The height of maximum reflectance factor was mostly in the lower part of the storm,close to somewhere quarter to its base.H BASE average was much lower than the mean averaged over all the supercell storms of the Yangtze-Huaihe region,but H TOP average was slightly lower.（2 ）I VIL average was 25.6 kg/m2 ,and Z MX average was 54.8 dBz.I VIL average was much smaller than the mean averaged over all supercell storms of the Yangtze-Huaihe region,but Z MX average was slightly lower.（3 ）MBASE average of the tornado supercell storms was 1.2 km,MTOP average was 3.9 km,and MSHR average was 14.4×10 -3 s-1 .Compared to the average for the Yangtze-Huaihe region,tornado MBASE and MTOP were obviously lower,but MSHR was slightly lower.（4）When TVS （Tornado Vortex Signa-ture）parameters got the maximum value,V AD was between 12 and 45 m/s,theV LLD was greater than 30 m/s,V MXD was larger than 30 m/s,the hight ofV MXD was not lower than 0.8 km,T DPT was between 2.4 and 6.4 km,the T BASE was between 0.7 and 1.5 km,TTOP was between 2.3 and 6.4 km,and T MXSHR exceeded 22×10^ -3 s^-1 .The maximum parameter occurrence time of TVS agreed with the actual time.On average,tornado appeared within 6 min after TVS appeared.And,（5）0-6 km vertical wind shear of the tornado supercell storm as detected by the radar was 15.2 percent higher than the averaged value over the Yangtze-Huaihe region.I CAPE average was 1752 J/kg,K index was 38℃,wind shear average from 850 hPa to the ground ex-ceeded 12 m/s,and,the temperature difference from 850 to 500 hPa was 23.7℃ before tornado happened.The energy was on a moderate to strong condition,the instability of the atmosphere was higher,and vertical wind shear became larger.
出处
《气象学报》
CAS
CSCD
北大核心
2014年第2期306-317,共12页
Acta Meteorologica Sinica
基金
国家自然科学基金项目(41140036
40475017)
关键词
龙卷
超级单体风暴
中气旋
TVS
环境参数
Tornado, Supercell storm, Mesocyclone, TVS, Environmental parameter
