东江水库对山区盆地大气强对流活动的影响

Impact of Dongjiang Reservoir on Severe Atmospheric Convection in Mountainous Area Basin

鉴于山区水库盆地多山地峡谷,拥有大面积水体,其动力和热力非均匀性对强对流活动的影响亟待研究,以2006年7月热带气旋碧利斯(Bilis)活动期间发生于湖南省东江水库的一次强对流活动为例,基于高时空分辨率的多普勒天气雷达基本反射率数据,利用时空数据分析方法探索这次强对流活动的特征,揭示强对流活动在水库盆地复杂地表环境影响下的活动规律。研究发现,该带状强对流系统的活动集中于水库盆地之内,造成了盆地内外降水的巨大差异,而马蹄形盆地地形可能是造成此现象的重要原因之一;强对流系统的发展和移动路径与库区内山地、峡谷的走向高度一致,喇叭口等地形有助于对流活动的增强;东江水库大面积水体与陆地形成的水陆热力性质差异,也可能有助于强对流活动的发展。

Due to the large areas of water and mountainous terrain,the inhomogeneous characteristics of the reservoir basin in mountainous area have a significant impact on severe convections.Based on high-resolution Doppler radar reflectivity data,a severe thunderstorm occurred in Dongjiang Reservoir basin during the period of Typhoon Bilis（2006）has been introduced to study the relationships between the large reservoir basin and severe convections.Our investigations found that the banded-structure thunderstorm concentrated in Dongjiang Reservoir basin and contributed great rainfalls amount in the basin,which probably was a result of the basin＇s U-shaped topography.Moreover,the tracks of the thunderstorm coincided with the mountain ranges and valleys in the basin,and the trumpet-shaped topography could intensify the thunderstorm.Besides,the water-land thermal difference in Dongjiang reservoir basin also could contribute to the development of the severe convections.