2008—2012年东北三省强对流天气的统计分析

Statistical Analysis of the Strong Convective Weather in the Northeast China

针对东北三省强对流天气短时预报的难题,首先统计分析了该地区强对流天气发生的时空分布特征,发现2008—2012年东北三省强对流天气主要发生在14—20时,而在08—14时相对较少;主中心区基本维持在辽宁西部地区,发生频数呈"南北多、中间少"的态势,且月平均发生频数逐月减小。其次,以哈尔滨、长春和沈阳站为例,利用实况探空资料计算对流参数,并对强对流天气历史样本进行预报技巧评分,确定对流参数阈值,回报TSS评分最大可达0.477。最后,通过2013年的独立样本的试报,检验新的阈值。检验结果表明,TT、TTMod和MK指数对东北三省的强对流天气有较好的指示意义。综合分析历史和独立样本,利用08时探空资料计算各指数作预报时,哈尔滨和沈阳地区TT、TTMod指数的预报效果相对较好,而长春地区TTMod和MK指数预报效果较好。

Aiming at the problem of strong convection weather nowcasting of Northeast region, firstly, the spatial-temporal distribution of strong convection weather was analyzed by using the routing sounding and surface observation data from 2008 to 2012. The results show that severe convective weather mainly occurred in the north and the south parts, with a dominant center located in the west of Liaoning Province. The severe convective weather mainly occurred during 14 ：00-20：00 in the Northeast China. Secondly, taking Harbin, Changchun and Shenyang stations as examples to calculate the stability indexes. By comparing the skill scores of the historical sample test results, the maximum TSS skill score of severe convective weather reached 0.477.Finally, through the 2013 independent sample test report, the results show that there was a good indication of TT, TTModand MK indexes for the strong convection weather in the northeast region. According to the comprehensive analysis of the history and the independent samples, the forecast effect of TT, TTModindexes in Harbin and Shenyang area was relatively good, while the TTMod and MK indexes forecast effect was better in the Changchun area by using 08：00 radiosonde data to calculate the index.