Gfdl's SPEAR Seasonal Predictions: Initialization and Bias Correction with Coupled Data Assimilation

Experimental operational seasonal predictions are successfully initialized in GFDL's new SPEAR prediction system. The new initialization scheme includes models with two atmosphere resolutions, and is based on coupled model analysis with improved ocean data assimilation (ODA) in SPEAR's MOM6 ocean component. The new ODA system makes use of efficient parallelization and MOM6 library, and its speed enables an iterative approach to improve coupled model initialization. The impact of atmosphere nudging on seasonal prediction is explored with the SPEAR prediction system. A new ocean tendency adjustment (OTA) scheme is explored with the climatological increments of ocean state variables from ODA in the ARGO era. OTA can serve as bias correction for both the reanalysis and prediction. Preliminary results of seasonal predictions with OTA show reduced model drift and improved ENSO anomaly prediction.