The Impact of Diurnal Air–Sea Coupling on the Surface and Atmospheric Energy Balance during the Suppressed Phased of the MJO

While investigations continue to show the importance of atmospheric moist dynamics and convection as a driving factor in the development and propagation of Madden Julian Oscillation (MJO) events, it is also known that the upper ocean mixed layer responds strongly and may feedback onto the development and decay of related intraseasonal variability. Results from the recent DYNAMO campaign have indicated a potential role for diurnal modulation of convection in preconditioning of the environment prior to the active phase of the MJO. However, the exact mechanisms by which this diurnal coupling arises and the resultant impacts on surface and atmospheric energy budgets remain unclear. How do air-sea feedbacks relate to the observed diurnal modulation?

This work will provide a long-term (15-year) multi-faceted diagnostic analysis of the surface and atmospheric energy balances during the suppressed-to-active transition of the MJO events over the Indian Ocean. Observations from multiple satellites (AIRS/AMSU, MODIS, CERES), reanalyses, and in situ observations (buoys, Argo) are used to investigate moisture and energy variability specifically with respect to the strength of diurnal ocean surface temperature warming. The diurnal modulation of clouds and associated radiative fluxes are discussed. Finally, the consistency of estimated surface energy fluxes with oceanic mixed layer heat content variability is examined.