The Observed Behavior of Global Convection from an A-Train Perspective

Abstract:

Atmospheric convection plays a key role in influencing the large-scale circulation, but how the local environment impacts convective behavior and the associated radiative and precipitation features remain uncertain. Measurements from field campaigns have proven useful in postulating what processes produce the most intense storm systems and how these systems evolve, yet such measurements are limited to a small time period and geographic location. Using a global database of convective objects generated from four years of A-Train measurements, we extrapolate the seasonal cycles of the most intense storm systems observed in several field campaign regions globally and quantify how the anvil structure, precipitation yield and cloud fraction, and other characteristics vary with storm intensity and environment. We leverage the day and night sampling of instruments on board the A-Train to contrast the character of daytime and nighttime convection. Initial results suggest that the population of the most intense storms is greatest over the Amazon and the Congo, yet these storms tend to be smaller and yield less precipitation than those found in Southeast Asia and the tropical East Pacific Ocean. The roles of environmental conditions, such as vertical wind shear and large-scale vertical motion, in driving anvil area, precipitation production, and storm intensity are investigated.