PNNL

Abstract

It has been proposed that air pollution increases the updraft speeds of warm convective clouds by reducing their supersaturation and, thereby, enhancing their buoyancy. Observations from the GoAmazon field campaign, sampled using subjective criteria, have been offered as evidence for this warm-phase invigoration. Here, we reexamine those GoAmazon observations using objective criteria and find no evidence that air pollution increases warm-phase updraft speeds. In particular, the observations yield no statistically significant relationship between aerosol concentrations and either moist-convective vertical velocity or reflectivity.