Abstract

Doppler radar data (radial velocity and reflectivity) assimilation capability has been developed with the MM5 3D-Var system. To assimilate radial velocity and reflectivity data, the 3D-Var system includes analyses of vertical velocity increments, as well as the increments of cloud water and rainw... Show moreDoppler radar data (radial velocity and reflectivity) assimilation capability has been developed with the MM5 3D-Var system. To assimilate radial velocity and reflectivity data, the 3D-Var system includes analyses of vertical velocity increments, as well as the increments of cloud water and rainwater mixing ratios. The model total water mixing ratio is used as a control variable in the MM5 3D-Var system. A warm rain process, its linear and adjoint are incorporated into the system to partition the moisture and water hydrometeor increments. Richardson's equation is used to balance the increments of vertical velocity and other dynamic and thermodynamic variables. The observation operators for Doppler radial velocity and reflectivity are developed and incorporated into the 3D-Var system. A case study is conducted for the landfalling Typhoon Rusa (2002) in South Korea. Experiments show positive impacts of assimilating Doppler radar data on the tracks and rainfall simulations of Typhoon Rusa (2002). Show less