冷涡背景下风廓线资料在沈阳对流天气预报中的应用

Application of Wind Profiler Radar Data to Convective Weather Forecast Under Background of Cold Vortex in Shenyang

选取2013年9月—2014年10月影响沈阳城区的冷涡个例,利用风廓线雷达探测产品,分析其在两类对流天气(雷暴类和冰雹类)中的变化特征,寻找预警指标。结果表明:通过分析环流背景场、物理量特征值和风廓线雷达探测产品可以判别对流类型,且具有一定的预警时效。两类对流发生前均出现动量下传现象,雷暴类下传时间早于冰雹类,但大值风速偏小;雷暴类大气折射率结构常数大值区高度、垂直风切变大值区高度和对流发展高度均低于冰雹类。

Based on cold vortex cases influencing Shenyang during September 2013 to October 2014 and wind profiler radar data,the characteristics of profiler products were compared between thunderstorm and hailstone weather processes,and some nowcasting indicators were found. The results show that the severe convective weathers could be judged according to the diagnosis of large-scale circulation background,the physical quantity characteristic value and the profiler products. On this basis,some results were helpful to warning effectiveness. Before the two kinds of convective weathers happened,there was phenomenon of momentum transport downward,but it occurred earlier for thunderstorm weather,and extreme wind speed was smaller. The altitude of big value area of atmosphere refractive index structure constant and vertical wind shear,and convection development height were lower under thunderstorm condition than those under hail condition.