Toward the Development of a Coupled COAMPS-ROMS Ensemble Kalman Filter and Adjoint with a focus on the Indian Ocean and the Intraseasonal Oscillation

LONG-TERM GOALS.The long-term goals of this research project are to: 1. Develop a regional coupled ocean-atmosphere model comprising the Navys CoupledOcean/Atmosphere Mesoscale Prediction System (COAMPS) and the Regional OceanModeling System (ROMS). 2. Explore data assimilation strategies in regional coupled ocean-atmosphere models with aspecific focus on air-sea interaction in the tropical Indian Ocean. OBJECTIVES.The project has the following objectives:(1) Interface ROMS and COAMPS with the Data Assimilation Research Testbed (DART)system at NCAR.(2) Compare the performance of the Ensemble Kalman Filter (EnKF) using the DataAssimilation Research Testbed (DART) and 4-dimensional variational (4D-Var) approaches todata assimilation in ocean only and atmosphere only experiments.(3) Develop a coupled model capability based on the pre-existing COAMPS and ROMS systemsusing the Earth System Modeling Framework (ESMF). (4) Investigate the merits of the EnKF approach for assimilating data into a coupled model,particularly in the highly dynamic tropical Indian Ocean where air-sea interactions play afundamental role shaping the monsoon circulation.