SURFACE WIND OBSERVATION DATA ASSIMILATION IN GRAPES

With the advances of numerical weather simulation and reduced data assimilation updating cycle,surface observation data assimilation becomes more and more important in data assimilation systems,and a better data assimilation system should contain the restriction of thermodynamic processes in the surface layer.In this paper,a new surface wind observation operator is utilized in GRAPES_3DVAR,with the restriction of thermodynamic process in PBL.In order to research the ability of assimilation and forecast with new surface wind observation operators,some experiments are run using the GRAPES model.The major results indicate that the new method of surface wind observation operator has positive impact on forecast with GRAPES model.