GFDL's SPEAR seasonal prediction system: Initialization and Ocean Tendency Adjustment (OTA) for coupled model predictions

SPEAR is an effort to develop a seamless system for prediction and research across time scales. The ensemble-based ocean data assimilation (ODA) system is updated for Modular Ocean Model Version 6 (MOM6), the ocean component of SPEAR.

Ocean initial conditions for seasonal predictions, as well as an ocean state estimation, are produced by the MOM6 ODA system in coupled SPEAR models. Initial conditions of the atmosphere, land, and sea ice components for seasonal predictions are constructed through additional nudging experiments in the same coupled SPEAR models. A bias correction scheme called ocean tendency adjustment (OTA) is applied to coupled model seasonal predictions to reduce model drift.