Weakly coupled atmosphere-ocean data assimilation: CAM-DART-POP [poster]
Hoar, T. J., Yeager, S., Collins, N. S., Raeder, K. D., Anderson, J. L., Danabasoglu, G., … Tribbia, J. (2010). Weakly coupled atmosphere-ocean data assimilation: CAM-DART-POP [poster]. In . Boulder, CO, US.
The Data Assimilation Research Testbed (DART) ensemble Kalman filter has been combined with the Community Atmosphere Model (CAM) and the Parallel Ocean Program (POP) to create weakly coupled ensemble analyses of the ocean that maintain a more desirable ensemble spread than if POP is forced with a... Show moreThe Data Assimilation Research Testbed (DART) ensemble Kalman filter has been combined with the Community Atmosphere Model (CAM) and the Parallel Ocean Program (POP) to create weakly coupled ensemble analyses of the ocean that maintain a more desirable ensemble spread than if POP is forced with a single atmosphere. The impact on the ocean of using an ensemble of atmospheric forcings is assessed by comparing the fit to the observations and the ensemble spread. The spread can be thought of as a measure of the uncertainty in the estimate of the system. Ensemble methods typically produce too little ensemble spread and analyses that give too little weight to observations. DART/CAM is used to create an 80-member atmospheric reanalysis assimilating all observations used in the NCEP/NCAR reanalysis. Each member of the CAM assimilation is forced from below by a single ocean analysis. A 48-member reanalysis with DART/POP is created using all temperature and salinity observations available in the World Ocean Database. The atmospheric forcings required for POP are obtained from the first 48 ensemble members from the CAM reanalysis, such that each POP instance uses a different sample estimate of the atmospheric forcing. The baseline case uses a single atmosphere for all the POP ensemble members. Show less