New developments of the real-time operational NCAR-ATEC ensemble-RTFDDA (E-4DWX) forecasting system

The E-RTFDDA (ensemble real time four dimensional data assimilation) is a WRF-based innovative mesoscale real-time ensemble data analysis and forecasting system, which contains multi-model, multi-physics and multi-perturbation approaches, and is the core of ATEC (US Army Test and Evaluation Command) four-dimensional weather system (E-4DWX) technology. A 30-member E-RTFDDA system with three nested domains with grid sizes of 30, 10 and 3.33 km has been running on a Department of Defense high-performance computing platform for years. Several other E-RTFDDA systems have also been implemented for supporting real-time wind energy prediction in US and China.

This study focuses on several new enhancements to the E-RTFDDA system. The NCAR DART-EnKF (Data assimilation research testbed-ensemble Kalman filter) system has been integrated into E-RTFDDA to enhance the E-RTFDDA member perturbation and data assimilation. The enhancement allows DART EnKF to take the advantages of E-RTFDDA by deriving error covariance using the multiple perturbation E-RTFDDA forecasts; and meanwhile, the updated EnKF means and a subset of EnKF members are used to perturb initial conditions. Also integrated are the WRF-NMM (non-hydrostatic mesoscale model system) and the WRF SKEB (stochastic kinetic-energy backscatter scheme) ensemble perturbations. The results of the system performance and sensitivity studies will be presented.