摘要
利用探空、地面观测资料和NCEP 1°×1°再分析资料,对2015年8月14日川西平原暖区暴雨进行了诊断分析和数值模拟。结果表明,副热带高压增强北抬,低层南风建立,东亚大槽南压引导偏北风进入四川盆地与南风辐合,从而导致了强降水。南风为暴雨区提供了水汽,使近地层假相当位温明显增大,导致川西平原上空对流不稳定加剧,配合较强的垂直上升速度,有利于出现暴雨。经中尺度滤波后,成都、乐山均出现辐合流场,揭示出暴雨开始和南移的过程。低层的风场辐合是成都强降水的动力抬升机制,数值模拟发现700h Pa偏北风和偏南风辐合,是眉山强降水的触发机制。乐山的水汽和抬升条件较弱,其降水也明显弱于眉山和成都。
By using sounding data, surface observation and 1° X 1°NCEP reanalysis data,diagnostic analysis andcal simulation have been performed for a heavy rainfall on August 14, 2015 , in warim region results shoethat the subtropical high strengthened and moved northward, the south wind in the lower troposphere came by. TheEast Asia trough moved southward, led the low _ level northerly winds into Sichuan Basin. The northerly and southerly windsconverged, which resulted in the heavy rain. The south wind provided moisture, enlarged the potential pseudo _ equivalenttemperature in the layer near the surface which made convective instability intensified, and velocity, all that was advantagous to heavy rainfall. By mesoscale filtering, There was convergence in flow field in Chengdu andLeshan, which corresponded to the beginning and southward moving of the rainstorm. The dynamic lifting mechanism of rainstorm in Chengdu. The numerical simulation found that the convergence of northerly andsoutherly winds at 700hPa was triggering mechanism of rainstorm in Meishan. Less moisture and weaker lifting that in Chend or Meishan resuilted in less rainfall in Leshan.
出处
《高原山地气象研究》
2017年第3期31-39,共9页
Plateau and Mountain Meteorology Research
基金
眉山市气象局科研项目"成都平原一次暖区短时强降水特征分析及数值模拟"
关键词
暖区暴雨
对流不稳定
湿位涡
中尺度滤波
数值模拟
heavy rainfall in warm region, convective instability, moist potential vorticity,mesoscale filtersimulation
