The parallel tangent linear and adjoint models for WRF (WRFPLUS V3.3) have been re-developed based on latest WRF model since 2010. Compared to the previous version of WRFPLUS, WRFPLUS V3.3 has significant improvements on the parallel performance, accuracy and software stability. It can be used in data assimilation, adjoint analysis and forecast sensitivity to observation (FSO) etc.

So far, in addition to its applications in adjoint analysis and FSO, WRFPLUS V3.3 has been coupled with WRF data assimilation system (WRFDA) toward the WRF 4D-Var system and coupled with Gridpoint Statistical Interpolation (GSI) system toward the GSI based WRF 4D-Var system. This talk will give a brief introduction about the development, performance of WRFPLUS V3.3 and its application in WRF 4D-Var and GSI based WRF 4D-Var.