National Aeronautics and Space Administration

Abstract:
The relative merits of different ocean observation systems (moored buoys, Argo, satellite, XBTs and others) are evaluated by their impact on ocean analyses and subseasonal forecast skill. Several ocean analyses were performed where different ocean observation platforms were withheld from the assimilation in addition to one ocean analysis where all observations were assimilated. These ocean analyses products are then used for initializing a set of subseasonal forecasts to evaluate the impact of different ocean analyses states on the forecast skill. Results from the NASA GMAO and the European Centre for Medium-Range Weather Forecasts (ECMWF) assimilation systems and ensemble prediction systems’ experiments will be presented to highlight changes in the ocean analyses states in the tropical Indian and Pacific Ocean and their impact on the forecast skill from weather to subseasonal timescales. Coupled air-sea interaction processes relevant to weather and intraseasonal variability in the earth’s climate system are inadequately represented in regional and global coupled models. These inaccuracies could be related to either poor parameterization of model physics or insufficient model resolution to resolve the critical processes. New efforts in observations, process understanding and translation into weather and climate models are necessary for improvements in simulation and prediction of the intraseasonal variability and associated weather events. We will discuss the merits of different observation platforms in this context and future observation and model improvement pathways.