Biomass-burning aerosol over northern Australia

Abstract

Australia’s two main continental aerosol types are mineral dust from the arid interior, and smoke from biomass burning in the tropical north. In this study we examine the seasonal cycle of aerosol optical properties from two sites in the Australian tropics: Lake Argyle and Jabiru. In each case we see a distinct seasonal cycle, with highest values of aerosol loading occurring during spring, the height of the savanna burning season. The seasonal cycle of Ångström exponent, a simple but effective guide to particle size, shows that it is fine mode particles which dominate during this time, as expected of biomass burning aerosol. We have also examined size distribution retrievals, and found similar results. An examination of these distributions for successive days showed results consistent with the dual effects of advection, and particle growth expected of smoke aging