云导风资料同化在伴随模式同化系统中的应用

以一次发生在长江流域的暴雨过程为例,设计了几种数值试验方案,并进行模拟。结果表明,MM5伴随模式同化系统能有效改善初始场与模式的协调能力,提高模式对于降水场和其它要素场的预报;使用云导风资料修正初始场后直接模拟的效果比未使用时直接模拟的效果要好,对部分区域的强降水预报精度有一定程度的改善;使用伴随模式同化系统后,加入云导风资料的同化试验对其它要素的改善与直接同化常规资料的效果相比,改善优势不明显,但从各要素的误差来看,对于风场的改善最好。

Application of Cloud-Derived Wind Data Assimilation in MM5 Adjoint-Modei Assimilation System

Data assimilation experiments are conducted with the MM5 adjoint-model assimilation system made by adjoint codes.With a case of heavy rainfall occurred on 23 and 24 July 2002,several numerical simulation experiments with different schemes are performed.The results indicate: the MM5 Adjoint-model Assimilation System can not only improve the initial field effectively and promote the coordination with the model but also enhance precipitation and other elements' forecasts;the assimilation of cloud-derived wind(CDW) can improve the quality of upper-level winds;the effect of direct numerical simulation with CDW to improve the initial field is better than that without CDW;when using the adjoint-model assimilation system,the experiment adding CDW can directly improve the wind forecast,but comparing that without adding CDW,there is no obvious improvement over other elements' forecasts.