资源环境科技发展态势分析平台

The Indian Space Research Organization launched SCATterometer Satellite-1 (SCATSat-1) satellite by PSLV-C35 on 26 September 2016 from Sriharikota. In this study, SCATSat-1 retrieved winds are assimilated in the regional atmospheric model subsequent to preliminary evaluation of SCATSat-1 retrieved winds against National Centers for Environmental Prediction final analyses. The Weather Research and Forecasting (WRF) model and its three- and four-dimensional variational (3D-Var and 4D-Var) data assimilation system are used to demonstrate the importance of SCATSat-1 retrieved winds on short-range weather prediction. In the first set of experiments, two parallel runs are performed with and without assimilation of SCATSat-1 retrieved winds using 6-hourly cycling during entire month of December 2016. Results suggest that assimilation of SCATSat-1 retrieved winds improved the WRF model analyses and subsequent forecasts of winds and moisture. In the second set of experiments, parallel assimilation experiments are performed with SCATSat-1 retrieved winds using 3D-Var and 4D-Var method for the entire lifetime of tropical cyclone Ockhi as a case study. Results suggest that assimilation of SCATSat-1 winds has positive impact on Ockhi tropical cyclone prediction with slightly better forecast skill for 4D-Var technique. Moreover, assimilation of SCATSat-1 retrieved winds improved predictions of surface convergence and accumulated rainfall. In the last set of experiments, forecast sensitivity to observations are performed for SCATSat-1 retrieved different resolution winds using the WRF tangent linear and adjoint models for the entire lifetime of tropical cyclone Ockhi. Results suggest that SCATSat-1 retrieved winds have positive impact on tropical cyclone simulation.