13A.2 A Tropical Cyclone Case Study using the Model Constrained 3D-Var Data Assimilation Scheme

Friday, 29 June 2007: 10:45 AM
Summit A (The Yarrow Resort Hotel and Conference Center)
Xudong Liang, Shanghai Typhoon Institute, Shanghai, China; and K. Zhao and D. Wang

More recently, some researches are focused on using weak constraints to reduce the dynamic imbalance between model variables based on the idea that unbalanced initial conditions often generates high-frequency oscillations with amplitude larger than those observed in nature. One of the approaches is using some physical constraints such as steady advective-diffusive equation in McIntosh and Veronis (1993), dynamical constraint in Brausseur (1991), Brausseur and Haus (1991) and Ishikawa et al. (2001). In this study, a new 3DVar method is proposed with full dynamics and physics in the numerical model as constraints following Ishikawa et al. (2001). The Model Constrained 3DVar (MC-3DVar) scheme can be resolved without time integrating but ensuring the balance between variables in the initial conditions. A MC-3DVar scheme is fulfilled using MM5 and its adjoint. Using this new 3DVar scheme, a tropical cyclone case is analyzed. To obtain the details of the landfall tropical cyclone, Multi-data such as Dropsonde, QuikSCAT, Cloud Drift Winds and Doppler Radar data are assimilated.
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