Impact of ocean observation systems on ocean analyses and subseasonal forecasts in the Indo-Pacific region

Abstract:

We evaluate the relative merits of different ocean observation systems (moored buoys, Argo, satellite, XBTs and others) by their impact on ocean analyses and subseasonal forecast skill of weather and climate phenomena in the Indo-Pacific region. 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. We then use these ocean analyses products for initializing a set of subseasonal forecasts to evaluate the impact of different ocean analyses states on the forecast skill. We use the European Centre for Medium-Range Weather Forecasts (ECMWF) ensemble prediction system and the Japan Meteorological Agency-Meteorological Research Institute (MRI) for the twenty-year sub-seasonal hindcast experiments. Results from these hindcast experiments will be presented to highlight changes in the ocean analyses states and their impact on the forecast skill of the MJO, monsoon intraseasonal oscillations, as well as temperature and precipitation in the Indo-Pacific region.

Coupled air-sea interaction processes relevant to intraseasonal variability (e.g. the MJO, MISO) in the earth’s climate system are inadequately represented in regional and global coupled models. These inaccuracies could be related to the 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 ocean observation platforms in this context and also future observation and model improvement pathways for better understanding and simulation of climate variability in the Indo-Pacific region..