湿热力平流参数在贵州初夏强降水中的运用

使用NCEP(1°×1°)再分析资料计算湿热力平流参数及其积分,通过对比分析2008—2009年初夏(5—6月)地面实况降水与该因子积分后的中心大值区的对应关系。理论分析表明:湿热力平流参数综合体现了锋区附近大气的动力、热力及水汽作用,相对于常用的相当位温、湿度等常用物理量来说,在一定程度上包含了广义位温及位温平流的相互作用,对实际非均匀饱和大气的动热力变化及水汽有较好的反映。统计分析也表明:积分后的湿热力平流参数中心值区与地面6小时强降水落区有较好的对应关系,它的变化趋势及移动方向与强降水区的变化也较一致,能作为短时强降水落区预报提供参考;利用NCEP/NCAR(1°×1°)再分析资料和Micaps地面实况降水资料,选取2009年6月7-9日发生在贵州的强降水过程为例,通过把湿热力平流参数与此次过程中动、热力场结合进行诊断分析,进一步表明该参数能综合地反应锋面强降水系统中的水汽、动力及热力的垂直结构特征,能作为造成强降水的锋面系统的示踪物。

Muggy advection parameter's application to summer heavy precipitation forecast in Guizhou

The Moist Thermodynamic Advection Parameter（Gmtp）,adopted by Gao et al,is studied in this paper.It is found that Gmtp,which contains information of interactions among general potential temperature and advection of potential temperature,may serve as a physical tracker to detecting weather system leading to frontal heavy rainfall.Utilizing the National Center for Environmental Prediction/National Center Atmospheric Research（NCEP/NCAR） 1°×1°grid data and the surface observational data with 6h interval to test the ability of calculated Gmtp in Gui Zhou during early summer（May and Jun） of 2008 and 2009.Meanwhile,one set of diagnoses are performed.The analyses indicate that the parameter shares a similar horizontal distribution pattern and evolution tendency with the 6-h accumulation of observed surface rainfall.They are closely correlated.