The Data Assimilation Research Testbed (DART): Ensemble Data Assimilation for NCAR Community Earth System Models

The Data Assimilation Research Testbed (DART) is a community facility for ensemble data assimilation developed and maintained by the National Center for Atmospheric Research (NCAR). DART provides data assimilation capabilities for nearly all NCAR community earth system models. The ensemble data assimilation tools provided by DART allow NCAR models to produce ensemble forecasts. The data assimilation process involves combining short model forecasts with observations to produce ensemble analyses that can be used for subsequent forecasts of any length. This process of confronting the model with observations facilitates model evaluation and improvement. The ensemble analyses and forecasts produced by DART can also enable analysis and understanding of the earth system. Examples are provided from a selection of NCAR community models and include: 1). Data assimilation in the newly developed regional configuration of the Model for Prediction Across Scales (MPAS); 2). Initial results from a multi-year atmospheric reanalysis with the Community Atmosphere Model (CAM6) in the newly released Community Earth System Model (CESM) version 2.0; 3). Data assimilation results of novel observations such as solar induced fluorescence (SIF) and total water storage (TWS) in the Community Land Model (CLM5) and the NOAH-MP components of the Community Terrestrial System Model (CTSM); 4). Application of DART to the WRF-Hydro hydrometeorological forecasting system; 5). Ensemble chemical weather prediction with the WRF-Chem regional atmospheric chemistry model.