摘要
利用FNL1°×1°分析资料对比分析广东前汛期的2次暴雨过程,结果表明:这2次降水都处在低空急流通道里,空气中深厚的高绝对水汽含量为降水提供了良好的水汽背景条件;降水落区主要在强垂直涡度差和弱的对流抑制相重合区域,925 h Pa的风速辐合为5月11日降水的主要系统,而5月17日的主要降水系统则为500 h Pa的短波槽。通过barnes带通滤波在低层流场中发现有中尺度系统与雨区相配合,有利于降水效率。5月11日500 h Pa槽线的南落以及切变线南侧强上升运动抑制了切变线附近的上升运动使得降水在粤北比预报偏小;5月17日数值预报未能预报出500 h Pa的短波槽使得暴雨漏报。
Using the FNL data, we analyzed two processes of torrential rain in the annually first raining season in Guangdong. The results are shown as follows. Located in a low-level jet, both of the rains were supplied with large amount of water vapor as good conditions of precipitation. They were mainly precipitated in areas where large differences of vertical vorticity met with weak convection inhibition. A wind-velocity convergence at 925 hPa was the main system for the May 11 rain while a 500-hPa shortwave trough played a major role in the May 17 rain. It was found through the Barnes band-pass filter that mesoscale systems were associated with the rain area in the low-level flow field, which helped increase rain efficiency. On May 11, a trough moved southward at 500 hPa and ascending motion was intense south of the shear, inhibiting the ascending motion near the shear to make rainfall less than the forecast. On May 17, the numerical prediction failed to forecast a shortwave trough at 500 hPa to result in the missing of the torrential rain in forecast.
出处
《广东气象》
2015年第4期10-14,共5页
Guangdong Meteorology
关键词
天气学
暴雨
前汛期
带通滤波
广东
synoptics
torrential rain
annually first raining season
band-pass filter
Guangdong
