Substantial Sea Surface Temperature Cooling in the Banda Sea Associated With the Madden‐Julian Oscillation in the Boreal Winter of 2015

Substantial (∼2°C) basin averaged sea surface temperature (SST) cooling in the Banda Sea occurred less than a 14-day period during 2015 boreal winter Madden-Julian Oscillation (MJO). Such rapid and large associated with MJO has not been reported at least last two decades. Processes that control substantial event are examined using high-resolution ocean reanalysis one-dimensional (1-D) model simulations. Previous studies suggest MJO-induced SST variability is primarily controlled by heat flux. However, budget analysis of indicates entrainment produced vertical mixing contributes more flux for driving basin-wide event. Analysis further demonstrates prominent coastal upwelling around islands southern occurs near end period. The upwelled cold waters advected currents to area within Sea, which maintains SST. These results compared another MJO-driven 2007 mostly driven Sensitivity experiments, initial conditions events replaced each other, demonstrate elevated thermocline strong El Niño largely responsible intensified generated colder subsurface waters.