Multiscale Air–Sea Interactions during TOGA COARE

Abstract

Abstract Two distinct intraseasonal oscillations (ISO) are found in the tropical ocean atmosphere in the western Pacific region during Tropical Ocean Global Atmosphere Coupled Ocean–Atmosphere Response Experiment (TOGA COARE). The ISO is characterized by cycles of dry–wet phases in the atmosphere due to the passage of Madden–Julian oscillations, and corresponding warming/shoaling–cooling/deepening cycles in the ocean mixed layer (OML). During the wet phase, 2–3-day disturbances and diurnal variations in the atmosphere are pronounced. During the dry phase, diurnal cycles in sea surface temperature (SST) is much enhanced while the OML is shallow. These multiscale coupled air–sea variations are further investigated with an ocean mixed-layer model forced by the observed surface heat, water, and momentum fluxes. The variations of ocean mixed layer are shown to be crucially dependent on the vertical distribution of solar radiation, that is, diurnal SST variability primarily determined by the absorbed solar radi...