PNNL

Abstract

The Maritime Continent (MC) exhibits a pronounced diurnal cycle in precipitation, with manyhigh-resolution models overestimating the diurnal peak and predicting earlier precipitation over the islands thanobserved. We hypothesize that part of this model bias comes from ignoring precipitation-induced surfacesensible heat flux (QP). To test this conjecture, we performed simulations with and without QP for April 2009and June 2006. The inclusion of QP reduced the bias in diurnal peak precipitation amplitude by 83% in April2009 and 23% in June 2006. Similarly, the bias in precipitation peak timing decreased by 26% and 15%,respectively. This bias reduction was even more prominent during periods of heavier rainfall. This improvement in both the amplitude and phase of diurnal precipitation also led to a reduction in bias for total precipitation by~10%. These findings suggest that QP cannot be neglected over the MC, particularly during heavy precipitation.