摘要
利用武汉新一代天气雷达资料,结合高空和地面观测资料,分析了2008年5月3日湖北东部一次强对流天气过程的弓形回波特征。结果表明:此次强对流天气过程的主要影响系统为500 hPa西风槽、低层切变线和地面冷锋,较强的层结不稳定和低层垂直风切变有利于弓形回波的产生;雷达资料分析表明,先后有三个不同空间尺度的弓形回波产生大风、暴雨等强对流天气,前两个由回波块、回波短带合并形成带状回波,该带状回波最后演变成一个尺度较大的弓形回波;弓形回波组合反射率因子达60 dBz,顶高14 km,垂直累积液态水含量55 kg/m2;弓形回波存在后部入流缺口、前沿强反射率因子梯度区及低层弱回波区;其后部有入流急流,两侧对应气旋性和反气旋性风场,且有γ尺度中气旋出现;地面中尺度低压带动弓形回波北部做涡旋运动,对逗点回波的形成有重要作用。
Bow echo of a severe weather event in the eastern part of Hubei on 3 MAY 2008 is analyzed with Wuhan CINRAD data and the observation data from upper-air and surface. The results show that 500 hPa trough, low-level shear line and surface cold-front formed the primary effective weather system. Unstable air and low-level vertical wind shear were favorable for bow echo occurrence. Radar data analyses showed that there were three different scale bow echoes which caused the severe convective weather. The first two were made by a merger of echo blocks and short echo line, then combined into echo line which evoluted into the last larger-scale bow echo and comma echo. Bow echo has the 60 dBz, 14 km top height, 55 kg/m2 vii, RIN, intensive reflectivity in the leading edge and WER. On velocity image, bow echo has RIJ corresponding to the cyclonic and anticyclonic wind field, low-level meso-γ-scale vortexes. Severe wind and rainstorm occurred in each stage of bow echo. The interaction of cold front and cyclonic stream field caused meso-scale low-pressure which makes the north of bow echo to move cyclonic and played a primary role in comma echo occurrence.
出处
《暴雨灾害》
2009年第4期306-312,共7页
Torrential Rain and Disasters
基金
中国气象局业务建设项目"灾害天气短时临近预报预警业务系统建设与改进"资助
