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Indian Ocean-Atmosphere Coupling: Its role on ENSO and Monsoon Variability. C. Perigaud (JPL), D. Neelin (UCLA), and J. McCreary (IPRC). Variability studied over 1980-2000 with:. * Data: FSU winds Arkin rainfall Reynolds SST
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Indian Ocean-Atmosphere Coupling: Its role on ENSO and Monsoon Variability C. Perigaud (JPL), D. Neelin (UCLA), and J. McCreary (IPRC)
Variability studied over 1980-2000 with: * Data: FSU winds Arkin rainfall Reynolds SST TOPEX sea level XBT from BRMC, Australia * Models: Indian and Pacific Oceans, Tropical Atmosphere, the Coupler the experiments (“forced” or “partially coupled”)
QTCM Atmosphere QTCM: Quasi-Equilibrium Tropical Circulation Model Neelin and Zeng (2000) Run forced by land + SST Reynolds 1980-2000---> CLIMa
IND4LM: Indian Ocean IND4LM:Model with 4-dynamic layers + halo-thermal mixing McCreary and Han (2000) Run forced by FSU winds +Arkin rain + Molinari heat---> CLIMo
OASIS Coupler OASIS: Ocean-Atmosphere SeaIce Soil, Terray et al. (1995) Here, it couples IND4LM (and tropical Pacific) with QTCM
FLXo=Anom+CLIMo SSTa=Anom+CLIMa FLXa=Anom+CLIMa SSTo=Anom+CLIMo
QTCM winds heat rain FSU winds Reynolds SST Ind4LM Sea level Salinity Temperature QTCM Ind4LM Experiments The two experiments differ by their inputs over the Indian ocean: Exp 0: SST_Ind4LM = Climatology Reynolds SST data Exp 1: SST_Ind4LM = 1980-2000 Reynolds SST data
Impact of Indian SSTs on Rainfall Rainfall at 92ºE, 7ºS
Conclusion • Indian SST anomalies are responsible for rainfall deficits over Indonesia in 1994 and 1997. Dipole mode is not the only mode of variability involving Indian Ocean-Atmosphere coupling. * Rain min associated with SSS min in 1994, with SSS max in 1997. * Forcing the Indian Ocean with realistic RAIN is crucial to simulate realistic SST.