Monday, 12 January 2004
Implementation of Coupled Skin Temperature Analysis and Bias Correction in the NASA GMAO finite-volume Data Assimilation System (fvDAS)
Hall AB
The NASA/NCAR finite-volume Global Climate Model (fvGCM) with the NCAR CLM (Community Land Model) version 2.0 was integrated into the NASA/GMAO fvDAS. Initially, an uncoupled surface skin temperature analysis and bias correction was performed based on GMAO TOVS (TIROS Operational Vertical Sounder) skin temperature observations. The bias correction technique uses TOVS observations along with 2 m conventional observations. A new method was developed for coupled skin temperature assimilation and bias correction where the analysis increment and bias correction term is passed into the CLM2 and considered a forcing term in the solution to the energy balance. For our purposes, the fvDAS CLM2 was run at 1° x 1.25° horizontal resolution with 55 vertical levels. The atmospheric analysis was performed 6-hourly, while the skin temperature analysis was performed hourly. The bias correction term, which was updated at the analysis times, was added to the skin temperature tendency equation at every timestep. Several assimilations were conducted and preliminary results will be presented.
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