塔里木盆地南缘沙尘暴天气的螺旋度特征分析

利用NCEP再分析资料和常规地面观测资料,对发生在塔里木盆地南缘的四次沙尘暴天气进行了螺旋度场的诊断分析。结果表明:沙尘暴发生区上空螺旋度的垂直分布特征在对流层下层为正值区(对应气旋式涡度区),在对流层中上层为负值区(对应反气旋式涡度区),这种垂直结构对形成像沙尘暴这样的中尺度天气系统而言,构成了低空强辐合、高空强辐散的深厚上升运动区,是十分有利于沙尘暴发展的一种型式。

Applying of helicity to analysis of sand-dust storms in south of the Tarim Basin

Using NCEP reanalysis data(horizontal resolution 1°×1°)and the conventional ground observational data,the helicity of four typical sandstorm happened in south of the Tarim Basin were analyzed.The results show that as an important physical parameter in analyzing and predicting strong convective weather,the helicity also has good indication in the forecasting of sandstorm in south of the Tarim Basin.The distribution of helicity over the sandstorm area were negative at higher levels and positive at lower levels during four sandstorm weather process.