The Impact of Assimilating FY-3C GNOS GPS Radio Occultation Observations on GRAPES Forecasts  

作　　者：WANG Jin-cheng GONG Jian-dong HAN Wei 王金成;龚建东;韩威(Numerical Weather Prediction Center,China Meteorological Administration,Beijing 100081 China;National Meteorological Center,China Meteorological Administration,Beijing 100081 China)

机构地区：[1]Numerical Weather Prediction Center,China Meteorological Administration,Beijing 100081 China [2]National Meteorological Center,China Meteorological Administration,Beijing 100081 China

出　　处：《Journal of Tropical Meteorology》2020年第4期390-401,共12页热带气象学报（英文版）

基　　金：National Key R&D Program of China(2018YFC1506205,2018YFC1506702)。

摘　　要：In the present study, a gross quality control (QC) procedure is proposed for the Global Navigation Satellite System Occultation Sounder (GNOS) Global Positioning System radio occultation (GPS RO) refractivity data to remove abnormal data before they are assimilated. It consists of a climate extreme check removing data outside the range of the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) climate maxima and minima over approximately five years, and a vertical gradient check that rejects profiles containing super-refractions. These two QC steps were applied sequentially to identify outliers in GNOS GPS RO refractivity data during boreal winter 2013/2014.All of the abnormal refractivity profiles and the outliers at each level of the GNOS GPS RO observations were effectively removed by the proposed QC procedure. The post-QC GNOS GPS RO refractivity observations were then assimilated in the Global/Regional Analysis and PrEdiction System (GRAPES) using the three-dimensional variational(3D-Var) system. The impacts of the GNOS refractivity observation on GRAPES analysis and forecasting were evaluated and analyzed using an observation system experiment run over one whole winter season of 2013/2014. The experiment results demonstrated a positive impact of GNOS GPS RO data on analysis and forecast quality. The root mean squared error of GRAPES analysis temperature was reduced by 1%in the Southern Hemisphere (SH) extratropics and in the tropics, and the anomaly correlation scores of the forecasted 500-hPa geopotential height over the SH increased significantly during days 1 to 5. Overall, the benefits of using GNOS GPS RO data are significant in the SH and tropics.

关 键 词：GNOS FY-3C GPS RO Global NWP data assimilation GRAPES 

分 类 号：P456.7[天文地球—大气科学及气象学]