WRF/DART Forecasts from Weather Research and Forecasting model, assimilation from Data Assimilation Research Testbed. DART is general purpose ensemble filtering system. Easily applied to new models and observations. Available to community. See

Open issues More frequent cycling and/or use of “time interpolation.” Effects on balance? Higher resolution, nests, multiple spatial scales

D1 D2 D3.. obs

3DVarEnKF

Initializing “True” State and Ensemble Construct N+1 initial states –AVN analysis (1 Jan 03) + perturbations drawn randomly from 3DVar covariances Construct N+1 lateral BC’s –AVN analyses (1-10 Jan 03) + perturbations –Perturbations are deviations from Jan climatology, scaled by 0.2 EnKF uses first N initial states and LBCs; true state use N+1st –Ensemble and true state drawn from same pdf