摘要
利用常规观测资料、NCEP再分析资料和自动气象站观测数据,分析了2013年12月14-15日河口县一次持续性的冬季暴雨天气过程。结果表明:此次冬季暴雨过程来自孟加拉湾的中高层深厚南支槽迅速加强东移,槽底深入孟加拉湾中部,槽前不断加强的西南急流将暖湿气流输送到滇南,底层切变线南移的同时配合地面冷锋,导致了此次河口冬季的持续性暴雨天气;此外,中低层来自孟加拉湾的暖湿气流在河口区域形成能量积集区和强烈的水汽辐合区,为持续性强降雨提供了充足的水汽;河口区域在底层辐合、中高层辐散的耦合作用下,有强烈的上升运动,槽前暖湿气流受低层冷空气和地形的强迫抬升作用,进一步加强了整层的辐合上升运动,为此次强降雨的发展提供了良好的动力抬升机制;由于地形原因,冷空气进入河口后,受河谷和山区地形影响在山前迎风坡一侧形成冷垫堆积,积蓄的对流性不稳定能量成为此次过程的触发机制。
Analyzed a continuous winter rainstorm weather process in Hekou County from Dec. 14th to Dec. 15th, 2013 through conventional observation data, NCEP reanalysis data and automatic weather station observation data. The results show that: in this process, the middle and high-level deep south branch trough from the Bay of Bengal quickly strengthened eastward, the trough low penetrated into the middle of the Bay of Bengal, the strengthening southwest jet stream in front of the trough transported warm and humid air to southern Yunnan, and the bottom shear line moved southward. At the same time,in conjunction with the ground cold front, it led to the continuous rainstorm in the winter of the estuary;during this process, the warm and humid airflow from the Bay of Bengal in the middle and lower layers formed an energy accumulation area and a strong water vapor convergence area in the estuary area,which is continuous Strong rainfall provides sufficient water vapor;the estuary area has strong upward movement under the coupling effect of bottom-level convergence and midto-high-level divergence. In addition, the warm and humid air flow in front of the trough is forced to uplift by the low-level cold air and topography, which further strengthens The convergent ascending movement of the entire layer provides a good dynamic uplifting mechanism for the occurrence and development of this heavy rainfall;due to topographical reasons, after cold air enters the estuary, it is affected by the valley and mountainous terrain to form a cold cushion on the side of the windward slope in front of the mountain Accumulated and accumulated convectively unstable energy becomes the trigger mechanism of this process.
作者
梁效铭
LIANG Xiao-ming(Hekou County Meteorological Bureau,Honghe,Yunnan 661300)
出处
《农业灾害研究》
2021年第9期61-62,共2页
Journal of Agricultural Catastrophology
关键词
冬季暴雨
南支槽
切变线
冷空气
Winter heavy rain
South branch trough
Shear line
Cold air
