Convective heating and precipitation estimates for the tropical South Pacific during fgge, 10‐18 january 1979

A modified version of ECMWF analyses is used to compute heat and moisture budgets during part of FGGE SOP‐1 (10‐18 January 1979) for an area which contains the South Pacific convergence zone (SPCZ). Precipitation estimates are derived as residuals and compared with those derived from a GOES IR satellite technique. The 12‐hour precipitation rates derived from the heat budget appear to be reasonably accurate, whereas those obtained from the moisture budget contain some error due to the contribution from the local rate of change term. Moreover, the heat budget estimates are generally in good agreement with the IR estimates. the axis of maximum precipitation derived from the heat budget is aligned well with the lowest values of outgoing long‐wave radiation (OLR), which represent high, cold cloud tops resulting from deep cumulus convection. As expected, the vertical advection term is found to be the dominant term in the heat budget which, together with radiative cooling, indicates an approximate balance between adiabatic cooling and diabatic heating. the vertical profiles of convective heating obtained from the heat budget are compared with those derived by other investigators using similar methods for other geographical regions. the present profiles, which show maximum heating near 500 mb, are more comparable to those for the western North Pacific than to those in the eastern Atlantic.