Laser ceilometer measurements of Australian dust storm highlight need for reassessment of atmospheric dust plume loads

The wide ranging impacts of atmospheric dust have received much attention over the past two decades. This research has been driven by need to better resolve the roles of dusts in atmospheric processes; biogeochemical cycles, particularly in response to changing land use and climate; and impacts on human health. Global dust emissions are estimated to range from 1000 and 2000 Mt yr(-1). These estimates have been derived from sediment budgets based on surface monitoring of dust concentrations, analyses of palaeo-dust deposits and satellite monitoring of dust plumes. However, significant discrepancies remain between estimated dust transport rates and dust deposition measured directly, or constructed from sediment records. Here we present the first surface based laser ceilometer measurements of a major dust plume in eastern Australia, the largest dust source of the Southern Hemisphere. Results indicate that previous estimates of dust plume loads may have been overestimated by up to 120%. We conclude that new research is required to accurately quantify dust plume loads to enable the highest confidence of modelled dust emissions and their impacts, particularly on climate at this time of unprecedented uncertainty of future climate. Citation: McGowan, H. A., and J. Soderholm (2012), Laser ceilometer measurements of Australian dust storm highlight need for reassessment of atmospheric dust plume loads, Geophys. Res. Lett., 39, L02804, doi: 10.1029/2011GL050319.