利用中尺度天气图分析方法, 结合雷达资料分析了2010年9月1日发生在陕西中部的一次强对流天气过程。结果表明: (1)在弱天气尺度系统影响下, 天气尺度分析不足以判断强天气发生的潜势条件; (2)探空资料的中尺度及其综合图分析能够清楚地反映冷暖平流、 干线、 湿舌、 显著流线及切变线的位置, 是强对流天气分析的有效手段; (3)08:00地面温度、 露点温度能较好地指示关中以北黄土高原上强对流发生的潜势条件, 通过14:00地面资料加密分析, 能清楚地看出地面冷锋的位置及冷暖、 干湿空气的交汇区域, 有利于确定强对流发生区域。(4)新生对流云主要位于地面干线附近, 下垫面对对流云初生也有较大的影响。尽管陕西西南部有较多的新生对流云, 但云顶延展高度较低, 产生闪电、 雷暴和冰雹等天气的几率较小。(5)对流云发展过程中形成的强天气指示回波对预警有重要的作用, 此次冰雹天气发展过程中形成明显的“V”形缺口、 回波穹窿及上冲云顶, 中层与下层强回波中心的水平位移超过1 km, 45 dBz强回波延伸高度超过7 km, 这些指标对强对流天气预警有较好的指示意义。
Using the mesoscale weather chart analysis technique and Doppler radar observation data, the mesoscale features of severe convective weather process in middle Shaanxi Province on 1 September 2010 are analyzed. The obtained results are as follows: (1) The synoptic-scale analysis can't well confirm the potential conditions of severe convective weather under the influence of weak synoptic-scale weather system. (2) The mesoscale and comprehensive analysis of radiosonde data can clearly reflect temperature advection, dry line, moisture tongue, significantly streamline, which is an effective means of analysis of severe convective weather. (3)The surface and dew point temperature at 08:00 can well indicate potential conditions of severe convective weather trigger in Loess Plateau in the north of Shaanxi, while the position of surface cold front and intersection region of clod and warm air or wet and dry air can be well shown by analyzing 14:00 surface data, which can help to determine the exact region of severe convective trigger. (4) Dry line and terrain have significant effects on convective cloud initiation, which mainly lies near underlying. Although more convection cloud triggered in southwestern Shaanxi, but cloud top height is lower than other region, so it has little possibility that lightning, hailstorm and thunderstorm are triggered. (5)The formated radar echo in the process of convection cloud developing plays an important role in severe weather warning. There is ‘V’-shaped gap, echo fornix and overshooting cloud top in process of the hail cloud development, and the central horizontal displacement between the middle level strong echo and the low level one is more than 1 km. The 45 dBz strong echo extended height in the storm is over 7.0 km. All of these metrics above are good indications of the severe convective weather warning.
[1]张小玲, 张涛, 刘鑫华, 等. 中尺度天气的高空地面综合图分析[J]. 气象, 2010, 36(7): 143-150.
[2]陆汉城. 中尺度天气原理和预报[M]. 北京: 气象出版社, 2000: 1-297.
[3]Browning K A. The evolution of tornadic storms[J]. J Atmos Sci, 1965, 22: 664-668.
[4]Browning K A. The growth environment of hailstones[J]. Met Mag, 1967, 96: 202-211.
[5]Lemon L R, Doswell C A. Severe thunderstorm evolution and mesocyclone structure as related to tornadogenesis[J]. Mon Wea Rev, 1979, 107: 1184-1197.
[6]Kropfli R A, Miller L J. Kinematic structure and flux quantities in a convective sto rm from dual-Doppler radar observations[J]. J Atmos Sci, 1976, 33(3): 520-529.
[7]Dixon M , Wiener G. Titan: Thunderstorm Identification, Tracking, Analysis, and Nowcasting-A radar-based methodology[J]. J Atmos Oceanic Tech, 1993, 10(6): 785-796.
[8]王在文, 郑永光, 刘还珠, 等. 蒙古冷窝影响下北京降雹天气特征分析[J]. 高原气象, 2010, 29(3): 763-777.
[9]刘一玮, 寿绍文, 解以扬, 等. 热力不均匀场对一次冰雹天气影响的诊断分析[J]. 高原气象, 2010, 30(1): 226-234.
[10]张腾飞, 段旭, 鲁亚斌, 等. 云南一次强对流冰雹过程的环流及雷达回波特征分析[J]. 高原气象, 2006, 25(3): 531-538.
[11]李江波, 王宗敏, 王福侠, 等. 华北冷涡连续降雹的特征与预报[J]. 高原气象, 2011, 30(4): 1119-1131
[12]许新田, 王楠, 刘瑞芳, 等. 2006 年陕西两次强对流冰雹天气过程的对比分析[J]. 高原气象, 2010, 29(2): 447-460.
[13]潘留杰, 朱伟军, 周毓荃, 等. 环北京地区八月风暴云的气候分布特征[J]. 高原气象, 2010, 29(6): 1579-1586.
[14]陶云, 段旭, 段长春, 等. 云南冰雹的变化特征[J]. 高原气象, 2011, 30(4): 1108-1118.
[15]顾光芹, 史印山, 池俊成, 等. 河北省冰雹气候特征及其与环流异常的关系[J]. 高原气象, 2011, 30(4): 1132-1138.
[16]Uccellini L W, Corfidi S F, Junker N W, et al. Report on the surface analysis workshop at the National Meteorological Center 25-28 March 1991[J]. Bull Amer Meteor Soc, 1991, 73: 459-471.
[17]杜继稳, 侯明全, 梁生俊, 等. 陕西省短期天气预报技术手册[M]. 北京: 气象出版社, 2007: 253-267.
[18]Dixon M. Titan user guide[EB/OL].(2005)[2009207220].http://www.ral.ucar.edu/projects/titan/docs/.
[19]周毓荃, 潘留杰, 张亚萍. TITAN系统的移植开发及个例应用[J]. 大气科学学报, 2009, 32(6): 752-764.
[20]朱乾根, 林锦瑞, 寿绍文, 等. 天气学原理和方法[M]. 北京: 气象出版社, 2003: 401-411.
[21]肖辉, 吴玉霞, 胡朝霞, 等. 旬邑冰雹的早期识别与数值模拟[J]. 高原气象, 2002, 21(2): 159—166.
[22]Lemon L R. On the use of storm structure for hail identification [C]. Preprints, 18th Conf. on Radar Meteorology, 1978: 203-206.
[23]Waldvogel A, Federer B, Grimm P. Criteria for the Detection of Hail Cells[J]. J Appl Meteor, 1979, 18: 1521-1525.