A STUDY OF THE DIABIATIC HEATING ASSOCIATED WITH THE MADDEN-JULIAN OSCILLATION

It has been inferred from numerous studies analyzing outgoing longwave radiation (OLR) data in the tropics that cumulus convection injects energy through released latent heat into the global-scale, 30-60 day (Madden-Julian, MJ) oscillation of divergent circulation, which is well portrayed by velocity potential (chi) anomalies. To substantiate this inference regarding the global scope of the diabetic hearing effect, we propose an chi-maintenance equation chi = chi-Q - chi-H A. The values chi-Q and chi-H A are the contributions of vertical differential diabatic and adiabatic heating to chi, respectively. The 4-year (1979 and 1985-1987) upper-air daily data generated by the Global Data Assimilation System of the National Meteoroligical Center were used to compute global chi, chi-Q, and chi-H A anomalies, and the global-scale chi-MJ oscillation is shown to be related to diabatic heating by H(VD)(= DELTA-2-chi-Q) anomalies. To understand the geographic relation between the differential diabatic heating effect and the global-scale chi-MJ oscillation, composite charts of chi and H(VD) anomalies during various stages of this oscillation were constructed. Centers of positive (negative) H(VD) anomalies coincided with divergent (convergent) centers of chi-anomalies. It was also found that the geographic distributions of our H(VD) anomalies and the OLR anomalies from previous studies resembled each other. These findings support the inferences from previous studies that maintaining the global-scale chi-MJ oscillation is linked to diabatic heating through the latent heat released by cumulus convection.