边界层风廓线雷达资料在浙中强对流天气中的应用

Application of Boundary Wind Profile Radar to Severe Convective Weather Forecast in Central Zhejiang

利用义乌CFL-03边界层风廓线雷达资料,对浙中地区15次强对流天气过程进行了分析。结果表明:(1)水平风不仅能提前于天气图数小时获知冷空气入侵,预判强对流的发生,而且通过对低空西南急流尤其是超低空西南急流或偏南急流的研究发现,其对短时暴雨或降雹能提供非常有利的信息,同时任何风向的超低空急流都可以作为判断雷雨大风的依据;(2)垂直速度和大气折射率结构常数(CN^(2))的大小能较好地反映降水开始和结束,而降水发生时,功率谱密度表现为正径向速度,谱宽变宽,且各信号形状较为相似;(3)当径向速度图出现速度模糊现象,尤其是在低层时,地面对应有大风。风廓线雷达资料对强对流天气的发生发展有较可靠的指示意义。结合多普勒雷达资料,可有效加强本地短临预报能力。

Fifteen severe convective weather cases are analyzed based on Yiwu CFL-03 boundary layer wind profile radar data. The results are as follows:(1) From horizontal wind data the information about cold air mass invasion can be obtained prior to weather synoptic maps. It is helpful to predict severe convective weather and low-level southwest jet, especially ultra low-level southwest jet or southerly jet, which is helpful for short-term rainstorms or hails. The ultra low-level jet is also an indicator of thunderstorm gales.(2) Vertical wind and CN~2 are good indicators to reflect the beginning and termination of a rainfall process. For rain events, radial velocity is positive, spectral width broadens in power spectral density diagrams, and the shapes of all signals are similar.(3) Velocity ambiguity in radial velocity maps denotes severe weather processes. Strong wind is happening if velocity ambiguity is at a low level. The wind profiler radar is a reliable instrument to predict the occurrence and development of severe convective weather. The local short-term and nowcasting capability can be effectively strengthened with the Doppler radar data.