Mechanisms Controlling the 4D Distribution of Rainfall and Latent Heating Over the Rainiest Region on Earth

Abstract

Global Precipitation Measurement satellite and ERA5 reanalysis data are used to study the 4D (latitude, longitude, altitude, time) distribution of rainfall intensity and latent heating fields over the rainiest region on Earth, located over western Colombia and the far eastern equatorial Pacific. The annual and interannual variability and the location of both variables' maxima are identified, and their spatiotemporal correlations are quantified. Static analyses of the winds show that the colder Choco low‐level jet (LLJ) and the warmer Caribbean‐Panama jet form a tropical frontal system. Dynamic analyses of 3D streamlines reveal that the Choco LLJ is at the core of a quasi‐permanent mini‐Hadley cell over the Pacific, with sinking motion between 6°S‐Equator and rising motion at 5°N–8°N, comprised between 1,000 and 700 hPa. Such vortex dynamics enhances the convergence of the northerly winds and the Panama jet, and exacerbates deep convection in association with the orographic lifting over the Colombian Andes. The large‐scale branches of that flow illuminate the shape and dynamics of the Walker cell over tropical South America. Correlation analyses illustrate the connections between rainfall and 3D winds as moisture transport mechanisms. Correlation and singular value decomposition analyses suggest that oceanic (continental) evaporation is associated with rainfall during the drier (wetter) season, and the importance of high‐levels temperatures and vertical integrals of diverse thermal and energy variables on rainfall bolster the view that the condensational heating is strongly coupled with the moisture transport flow and the convective ascent required to explain such extraordinary amounts of rainfall.