Extended Range Prediction System and its Application

Abstract

The demand for prediction of weather and climate in the extended range (i.e. 2-3 weeks in advance) is quite visible now a day in the sectors depending on water resources, city planning, dam management, health management (e.g. protection against heat death) etc.. The demand has grown up manifold in the last five years with the experimental implementation of dynamical extended range prediction system (ERPS) by Indian Institute of Tropical Meteorology (IITM), Pune. At the heart of ERPS is a forecast system based on the NCEP-CFSv2 Ocean-Atmosphere coupled dynamical model (hereafter CFS), which is configured to run in two resolutions (T382 and T126) and an atmospheric only version (hereafter GFS) configured to run with CFS sea surface temperature (SST) boundary condition that is bias corrected with observations. The initial conditions to run the model are generated through an in-house developed perturbation technique using NCEP GODAS data assimilation system. From every initial condition the model is run for the next 28 days and a multi ensemble forecast run is created. Forecast product variables are then separated for sector specific application with suitable post processing and downscaling based on advanced statistical techniques. The article gives a brief overview of ERPS keeping the focus on few sector specific applications.