[M-GI29] Data assimilation: A fundamental approach in geosciences

[MGI29-06] Development of a coupled atmosphere-ocean data assimilation system in the Japan Meteorological Agency: evaluation and future plan

*Yosuke Fujii^1,2, Chiaki Kobayashi¹, Ichiro Ishikawa¹, Yuhei Takaya¹, Toshiyuki Ishibashi¹, takuma yoshida³ (1.Meteorological Research Institute, Japan Meteorological Agency, 2.The Institute of Statistical Mathematics, 3.Japan Meteorological Agency)

Keywords:Coupled Data Assimilation, Tropical Instability Wave, TAO array

The Meteorological Research Institute (MRI) of the Japan Meteorological Agency (JMA) has been developing a coupled atmosphere-ocean data assimilation system for more than 10 year. The current system, MRI-CDA1, is based on the coupled atmosphere-ocean general circulation model and separated atmosphere and ocean analysis routines adopted in JMA’s operational weather and climate prediction systems. In this presentation, we evaluate the coupled reanalysis generated by MRI-CDA1, the sea surface air temperature field in the reanalysis. The atmosphere-ocean coupling generates realistic SST variations associated with tropical instability waves, and the SAT field responds to the SST variations in the subseasonal time scale. The SST-SAT relationships on the weather timescale were also recovered in the coupled reanalysis, although they are hardly seen in the uncoupled reanalysis generated by the same system. The coupled model physics generates weather timescale SST variations consistent with the atmospheric state, and the atmospheric parameters respond to the SST variations through the coupled model physics. As the result, correlations of SAT in the coupled reanalysis with buoy observations are increased. In this presentation, we will also introduce the future plan of the coupled data assimilation system development in JMA.