The Tropical Convective Evolution in Different Rain Types over the West and East Pacific

Abstract

The TRMM PR and GSMaP products are analyzed to examine the variability in different types of precipitation under three rain intensity classes for investigating the evolution of tropical convection over the tropical western Pacific (WP) and eastern Pacific (EP). Composite time series are constructed around the GSMaP precipitation maxima for different precipitation types identified from the TRMM PR. The composite evolution is further broken down into weak, moderate, and strong rains, divided by applying quartile-based thresholds to rainfall maxima. The results show that the evolution of deep convection reaches a precipitation peak earlier by a few hours than stratiform evolution precipitation for strong and moderate rain regardless of the region. Deep convective rain still predominates in the WP weak rain, while shallow precipitation dominates the weak rain in EP. The composite time series of vertical velocity is overall physically consistent with the expectation from these findings. It is implied that the convective-stratiform lag and tilted updraft structure for strong rain are shared between WP and EP, while the attribution of weak rain can differ significantly between the regions.