Self-Aggregation of Deep Convection and its Implications for Climate

Abstract

Purpose of Review: This paper reviews the self-aggregation of deep convection, its impact on the large-scale environment, its dependence on surface temperature, and its implications for climate. Recent Findings: Self-aggregation generates significant humidity variability, dries the mean state, reduces high cloud cover, and increases the ability of the atmosphere to cool to space. Some studies find that convection is more self-aggregated at warmer temperatures but other studies, or other ways of measuring the degree of self-aggregation, disagree. There is not a simple, monotonic relationship between self-aggregation and surface temperature. Summary: Self-aggregation, through its effect on the humidity distribution and radiative budget, can affect climate. However, there is uncertainty over how strong the modulation of climate by self-aggregation is, in part because of the ambiguity over its temperature dependence. There are some indications that self-aggregation may modestly reduce climate sensitivity even without a dramatic temperature dependence, but more research is needed to understand this behavior.