中哈边境迁飞蝗虫降落的天气过程分析——以1999年塔城地区为例

Analysis of the weather process in the landing of migratory locusts in China-Kazakhstan border area:a case study for Tacheng in 1999

为明确中哈边境迁飞蝗虫降落过程的气象背景,选择中哈边境塔城地区蝗虫迁飞为害最严重的1999年为例,基于当年迁飞蝗虫降落时间、地点及为害程度等数据,利用中尺度气象预报与研究(weather research and forecasting,WRF)模式模拟塔城地区迁飞蝗虫降落的天气变化。结果表明,垂直速度达到0.22 m/s的下沉气流、风速为3 m/s以上的东南风向、降雨和低于19℃的温度胁迫是影响1999年7月10日中哈边境迁飞蝗虫降落的主要气象因素;统计当年迁入蝗虫降落事件,发现下沉气流、风向切变、降雨和低温在蝗虫降落过程中出现的频次占总迁入蝗虫降落事件的70%、50%、30%和10%,其中下沉气流和风向切变是影响蝗虫降落的主导因子。表明利用WRF模式可准确预测迁飞蝗虫跨境为害降落区域的天气过程。

To clarify the meteorological background of the migratory locust landing in China-Kazakhstan border area,the year 1999 was selected as a case,when the locust migration caused the most serious damage in Tacheng Area,based on the data of landing time,location and damage of migratory locusts in 1999,and the mesoscale meteorological forecast and research model(WRF)were used to simulate the weather change.The results showed that the meteorological factors affecting the landing of migratory locusts on July 10,1999 included downdraft with a vertical velocity of 0.22 m/s,southeastern wind direction with a wind speed of more than 3 m/s,rainfall and temperature stress below 19℃.According to the statistical data,the frequency of downdraft,wind shear,rainfall and low temperature accounted for 70%,50%,30%and 10%,respectively,of which the downdraft and wind shear were the main factors.The results provide an important basis for predicting the landing areas of migratory locusts in China-Kazakhstan border.