华东区域快速更新同化试验

A RAPID UPDATE ASSIMILATION EXPERIMENT FOR EAST CHINA AREA SHANGHAI-NANJING EXPRESSWAY

基于GRAPES模式,使用快速更新循环同化技术,对华东地区五种观测资料(常规的探空资料TEMP、地面报SYNOP、飞机报AIREP、船舶报SHIPS和非常规的雷达VAD风资料)进行同化分析,通过2008年6月、7月和8月三个月的连续试验以及个例分析,初步检验GRAPES_RUC系统在上海的本地化情况。试验结果表明,GRAPES_RUC系统对小雨和中雨的预报较好,对暴雨(大于50 mm)几乎没有预报能力,这与参与评定的样本数有较大关系;GRAPES_RUC系统对形势场有较好的把握能力,总体上与NCEP分析场较为一致。总体而言,基于GRAPES模式建立的快速循环同化系统预报基本稳定可靠,且具有一定的预报能力和指导意义。模式基本能对强对流系统做出预报,但强度偏弱;而对于突发性较强的强对流系统,临近预报能得到较好的预报效果。

Based on GRAPES model and using the Rapid Update Cycle technique, five kinds of observation data are assimilated for the area of East China （TEMP, SYNOP, AIREP, SHIPS and radar VAD wind data）. In order to preliminarily verify the localization of GRAPES_RUC system in Shanghai, three months of continuous experiments and case analyses from June to August in 2008 have been performed. The results are shown as follows. The GRAPES_RUC system is good at forecasting light and moderate rain and almost has no forecast ability for heavy rain （greater than 50ram）, probably due to the number of samples verified. GRAPES_RUC system is able to grasp the synoptic situation field better, which is consistent with the NCEP analysis field. For case analyses of typhoons and heavy rain, GRAPES_RUC system also performances well. Overall, GRAPES_RUC system is basically stable, reliable, and is able of forecasting for guidance. The system is also able to forecast severe convective weather but underestimates the intensity. The system predicts well explosive convective weather.