Effects of anthropogenic pollution on warm clouds in the Amazon: a modelling study

Abstract

Amazonia is under continuous changes, and atmospheric aerosol concentrations there vary from natural clean conditions to heavy polluted, following the seasonal cycle of deforestation and agriculture practices. These high concentrations of aerosols play an important role in the atmospheric composition modification but also on convection, cloud formation and the precipitation regimes, with important regional and global climatic implications. Part of the anthropogenic pollution in the region comes actually from large metropolitan areas, such as Manaus, a city of two million people surrounded by 2000 km of pristine forest. The anthropogenic emissions from Manaus form a pollution plume that propagates downwind, interacting with the naturally occurring biogenic aerosol particles, modifying its optical and chemical properties. This situation provides an opportunistic setting for a mechanistic evaluation of anthropogenic perturbations to the properties of the atmospheric particle population, and its effects on clouds and climate. These are exactly the general objectives of the GoAmazon 2014/15 experiment. In this project, the student will use GoAmazon data to investigate the effects of anthropogenic pollution on the natural aerosol hygroscopicity and CCN activity and, using models, infer the potential effects on tropical warm clouds development. (AU)