More Intense, Organized Deep Convection With Shrinking Tropical Ascent Regions

Abstract

AbstractChanges in the frequency and morphology of convection in a warming climate have major implications for the hydrologic cycle and continue to be a large source of variability in climate models. Recent studies of model output indicate a narrowing and intensification of the ascending branch of the Hadley circulation (i.e., the Intertropical Convergence Zone). The present work uses tropical ascent area fraction (Au) and Tropical Rainfall Measurement Mission precipitation features to study global tropical variability in convection with ascent area changes in the current climate. Ascent region convection becomes more intense and organized when Au is low. Overall increases in mean precipitation as the tropical ascent regions shrink are primarily driven by an increase in the areal extent of convective systems, rather than intensity of the convective system rainfall, suggesting an increase in the organization and aggregation of convection as the climate continues to warm.