T639数值产品对影响新疆主要系统的预报检验评估

Verification and Assessment of the Forecasting of Influence System in Xinjiang by T639 Model Products

使用T639L60模式2009—2010年1°×1°分辨率72 h预报时效内的高度场预报产品及ECMWF客观分析场,采用天气学检验方法,对新疆主要天气影响系统(西西伯利亚低槽、乌拉尔大槽、北方横槽和中亚低值系统)数值产品的预报能力进行检验。主要从影响系统生成时间、中心强度、槽线位置、移动速度4个方面进行检验。检验结果表明:T639模式对新疆影响系统具有较好的预报性能,尤其对48h内的预报能力非常高。但因影响系统和预报时效不同其预报能力也有较大差异,对越深厚的低槽系统,T639模式的预报效果越好;T639产品对西西伯利亚低槽和乌拉尔大槽出现时间预报偏早的较多,而北方横槽和中亚低值系统偏晚的多;对西西伯利亚低槽和中亚低值系统槽线位置预报偏快的较多,而乌拉尔大槽和北方横槽偏慢的多。

Based on the T639 model data （1°×1°） of 72 h height field from 2009 to 2010 and the objective analysis data of ECMWF from September 2007 to February 2008 as well as the classification of synoptic system in Xinjiang, the forecast products were validated by synoptic verification method in terms of start time, intensity of system center, position of trough line, and the moving velocity of synoptic system. The results indicate that the forecast of synoptic system in Xinjiang is accurate based on T639 model, especially for 48 h forecasts. Forecast ability is different because of the difference of influence system and prediction time. The deeper the upper level trough, the better. The start time of synoptic system had an earlier pre- diction to West Siberian trough and Ural trough, and just the opposite for northern transversal trough and central Asia low-pressure system. The position of trough line had a faster moving prediction to West Sibe- rian trough and central Asia low-pressure system, and just the opposite for northern transversal trough and Ural trough.