Ocean Sci. Discuss., 9, 2535-2559, 2012
www.ocean-sci-discuss.net/9/2535/2012/
doi:10.5194/osd-9-2535-2012
© Author(s) 2012. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal Ocean Science (OS). Please refer to the corresponding final paper in OS.
Impact of the sea surface temperature forcing on hindcasts of Madden-Julian Oscillation events using the ECMWF model
E. de Boisséson1,2, M. A. Balmaseda2, F. Vitart2, and K. Mogensen2
1CNRM/GAME, URA 1357, 42 avenue Gaspard Coriolis, 31057, Toulouse, France
2European Centre for Medium Range Forecast, Shinfield Park, RG2 9AX, Reading, UK

Abstract. This paper explores the sensitivity of the prediction of Madden Julian Oscillation (MJO) events to different aspects of the sea surface temperature (SST) in the European Centre for Medium-range Weather Forecasts (ECMWF) model. The impact of temporal resolution of SST on the MJO is first evaluated via a set of monthly hindcast experiments. The experiments are conducted with an atmosphere forced by persisted SST anomalies, monthly and weekly SSTs. Skill scores are clearly degraded when weekly SSTs are replaced by monthly values or persisted anomalies. The new high resolution OSTIA SST daily reanalysis would in principle allow to establish the impact of daily versus weekly SST values on the MJO prediction. It is found however that OSTIA SSTs provide lower skill scores than the weekly product. Further experiments show that this loss of skill cannot be attributed to either the mean state or the daily frequency of OSTIA SSTs. Additional diagnostics show that the phase relationship between OSTIA SSTs and tropical convection is not optimal with repspect to observations. Such result suggests that capturing the correct SST-convection phase relationship is a major challenge for the MJO predictions.

Citation: de Boisséson, E., Balmaseda, M. A., Vitart, F., and Mogensen, K.: Impact of the sea surface temperature forcing on hindcasts of Madden-Julian Oscillation events using the ECMWF model, Ocean Sci. Discuss., 9, 2535-2559, doi:10.5194/osd-9-2535-2012, 2012.
 
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