Influence of the Madden-Julian oscillation on the Indian Ocean cross-equatorial heat transport

Abstract

The Indian Ocean cross-equatorial heat transport (CEHT) anomalies associated with the Madden-Julian oscillation (MJO) are analyzed using the National Centers for Environmental Prediction Climate Forecast System Reanalysis for the period 1979-2010. The magnitude of MJO-related CEHT anomalies, seasonal dependence, and interannual modulations are examined. The magnitude of composite MJO CEHT anomalies is ∼30% (∼15%) of the amplitude of the seasonal climatology in winter (summer). Interannual modulation on average accounts for only ∼10% of the total magnitude of intraseasonal variability of a given year. MJO CEHT is largely contributed by temperature flux anomalies in the upper ∼140-m, with notable compensation between two characteristic layers. The significance of MJO CEHT anomalies, the nonnegligible magnitude of residual CEHT accumulated from intraseasonal anomalies during specific years, and the vertical compensation of temperature flux anomalies that give rise to the CEHT, have implications to the potential importance of upper ocean thermodynamics in MJO evolution and regional climate. Key Points MJO's impact on Indian Ocean cross-equatorial heat transport (CEHT) quantifiedSignificance of MJO CEHT relative to seasonal/interannual components evaluatedImportance of vertical structure/resolution to MJO CEHT discussed