WRF Working Group 4: 3D-VAR Data Assimilation System

Lead: John Derber
Email: wrf-wg4@wrf-model.org
Website: Working Group 4


Bob Aune, (NESDIS)
Ed Barker, (NRL)
Dale Barker, (NCAR)
Shu-hua Chen, (U_UCD)
John Derber, (NCEP)
Dezso Devenyi, (FSL)
Jidong Gao, (CAPS)


We are developing advanced 3D- variational (3D-Var) data assimilation tools for the WRF model. The analysis system must be able to properly resolve all variables and scales of importance of the assimilation system. This formidable problem will be addressed incrementally by analyzing scales and variables, which we currently know how to do and developing techniques to perform the analysis at smaller scales and with additional analysis variables. We have designed the framework of a basic 3D-Var analysis scheme capable of analyzing most standard meteorological data, and more recently (V2.0) included a number of of non-traditional data types e.g. SSM/I radiances and radar radial velocity. The WRF assimilation research will strive to develop the "forward models" (and their adjoints) by which the WRF model fields can be transformed and interpolated to the observation locations and values for each of these data, and for these operators to be portable to alternative assimilation algorithms (e.g alternative 3D-Var systems, 4D-Var, ensemble-based DA, etc.).