The vertical moisture structure and precipitation intensity distributions associated with tropical convective systems

In the tropics, the majority of high-intensity precipitation comes from the organization of multiple convective cells into mesoscale convective systems (MCS). Here, we use a synthesis of multi-decade satellite and reanalysis data to investigate relationships between the column water vapor content (CWVC), instability (CAPE), and precipitation from MCS. We find a linear relationship between MCS maximum precipitation intensity and CAPE and a sharp, nonlinear relationship between this maximum precipitation intensity and CWVC. The latter suggests that a deep layer of inflow to the MCS dominates buoyancy and precipitation production. From these multidecade data, we can also illustrate robust shifts in the probability distributions of precipitation intensity with the El Niño Southern Oscillation. El Niño-La Niña relative gains and losses in precipitation intensity can be understood with a vertical momentum budget and the role of environmental relative humidity and large-scale circulation therein. Understanding the associated vertical moisture structure and instability is essential to better predict future variability in tropical precipitation.