三穗汛期强降水特征及地形影响分析

Analysis on the Characteristics of Heavy Precipitation and Topographic Influence in Flood Season in Sansui Guizhou

该文利用2010—2020年三穗县9个乡镇气象观测站降水资料,结合地形特征,运用对比分析方法,探讨三穗强降水天气时空分布特征与地形的关系。结果表明:5—9月是三穗强降水高发期,占全年强降水总次数的86.7%;在汛期相同环境条件下,由于三穗地形四周高、中心低,强降水大值中心分布在台烈—良上等偏西偏南一带,与三穗南高北低、西高东低的地形基本吻合,且降水不同量级日数分布与地形分布存在一致性,均呈现南部多于北部。另外,雨带多从偏西北、偏西、西南等方向进入并影响三穗,但受地形的影响降水呈不同的分布,尤其西南部地势较高并处于迎风坡,交汇气流在此停留时间较长,导致该处更容易出现强降水天气过程,且降水量往往更大。

Based on the precipitation data of the meteorological observation stations in the 9 towns of Sansui from 2010 to 2020,and in combination with topographic characteristics,the relationship between the spatial and temporal distribution characteristics of heavy precipitation and the topographic characteristics in Sansui is explored by using the method of comparative analysis.The results show that May-September is the period of high occurrence of heavy precipitation in Sansui,accounting for 86.7%of the number of heavy precipitation throughout the year.Because the terrain of Sansui is high all around and the center is low,under the same environmental conditions in the flood season,the large value center of the heavy rainfall in Sansui is mainly located in the south-west of Tailie-Liangshang,which is higher in the south and lower in the north.The topographical distribution of west-high and east-low is basically consistent,and the distribution of days of precipitation of different magnitudes is consistent with the topographical distribution,showing that there are more in the south than in the north.In addition,the rain belt mostly enters and affects the three ears from the northwest,west,southwest,etc.but the topography leads to a different distribution of precipitation levels.In particular,the higher terrain in the southwest often forms an upwind slope effect,which makes the flow of confluence.Staying in the southwest for a long time makes the southwest more prone to heavy precipitation weather processes,and the amount of precipitation is often greater.