GPS观测资料应用于中尺度数值预报模式的初步研究  

PRELIMINARY STUDY ON APPLYING GPS OBSERVATIONS TO MESOSCALE NUMERICAL WEATHER PREDICTION MODEL

作　　者：袁招洪[1,2] 丁金才[3] 陈敏[4] 

机构地区：[1]上海市气象局,上海200030 [2]南京气象学院,南京210044 [3]上海中心气象台,上海200030 [4]上海浦东新区气象中心,上海200235

出　　处：《气象学报》2004年第2期200-212,共13页Acta Meteorologica Sinica

基　　金：中国科学院知识创新工程重要方向项目 (KJCX2 SW T1 3 )

摘　　要：利用建立在长江三角洲地区GPS观测网中 11个站点的可降水量资料 ,对 2 0 0 2年 6月 2 3～ 2 4日影响长江三角洲地区的降水过程进行了MM5模式初始湿度场调整和Nudging同化试验。试验表明 :利用GPS测量的可降水量对模式初始湿度场进行调整能明显增强模式初始场描述水汽分布的能力 ,从而有效地控制模式积分初期对可降水量预报的误差 ,并对模式 6h累积降水量预报有较明显的改善作用。利用Nudging技术同化GPS可降水量资料对MM5预报效果改善较小 ,并且Nudging系数的增加对预报效果的影响不大。总体上 ,利用GPS可降水量资料调整模式初始湿度场对模式 6h累积降水预报效果的改善明显好于连续Nudging同化。试验还表明 :GPS资料对模式初始湿度场调整改善模式对累积降水量的预报主要是通过改善网格降水预报来实现的 ,而Nudging同化主要是通过改善次网格降水而提高模式降水预报能力的。Water vapor is a critical atmospheric variable for the description of the state and evolution of many physical processes. Lack of precise and continuous water vapor data is one of the major error sources in NWP. The Global Positioning System (GPS) can monitor the precipitable water (PW) continuously at low cost. The GPS data has been used to improve NWP in recent years. Based on the GPS precipitable water data at 11 sites of GPS networks in Yangtze delta, The experiments on initial humidity fields reanalysis and Nudging assimulation were conducted to investigate the improvement of MM5 simulation on railfall event from 23 to 24 July 2002. The results show that initial humidity fields reanalyzed by using GPS PW can obviously improve its capability in revealing the water vapor distribution, which can result in decreasing water vapor error in initial fields of MM5. It also can restrain PW prediction bias during the earlier period of model integration and improving the 6h accumulated precipitation prediction. Nudging assimulation of GPS PW data can improve precipitation prediction slightly with different effects at different precipitation thresholds, and increasing nudging gain coefficient play a little role in improving precipitation prediction. On the whole, the results which are obtained by the reanalysis are better than by the nudging assimulation. It's also found that the reanalysis influences the results of 6h accumulated precipitation on amount and occurring time through changing the non-convective precipitation prediction mainly. The precipitation prediction improved by the nudging assimulation are substantially associated with convective precipitation change.

关 键 词：GPS观测资料 中尺度数值预报模式 可降水量 同化 

分 类 号：P456.7[天文地球—大气科学及气象学]