Three years of dust monitoring in southern South América: what have we learned?

GAIERO, DIEGO M.

Puerto Madryn

Workshop; Multidisciplinary Workshop on Southern South American Dust; 2007

CIGeS/CENPAT/Weizmann Inst./NASA Goddard

The estimates for the magnitude of the dust fluxes from southern South America (SSA) are largely based on the model results, some of which have been suggested to have significant difficulties in reproducing the daily surface dust concentrations and the seasonal cycle of dust advection from Patagonia. Although models and satellite data analysis provide much needed information regarding the flux of mineral dust from Patagonia, both methods have significant drawback. Only in-situ measurements of mass concentration and vertical and horizontal fluxes can validate model and satellite estimates. In this talk I will present preliminary data of dust fluxes at five stations on SSA (Central Argentina and Patagonia) over a three year period. Each site is equipped with dust traps and a weather station. Two different types of traps are used for measuring wind blown flux: i) Big Spring Number Eight (BSNE) sampler suited to estimate horizontal fluxes and ii) pyramidal receptacles (CP), suited to estimate the vertical fluxes. Average vertical dust fluxes are higher in the northern part of the study area and are mainly associated to higher rainfall compared to Patagonia. On the contrary, along the Patagonian coast estimations of horizontal dust fluxes are more than 200 times compared to the vertical fluxes and to fluxes predicted by models. The higher horizontal dust fluxes measured during short time periods are linked to westerly storms producing dust events which typically last for 1 day. Our recent findings suggest that there is dust sources linked to numerous topographic lows widespread in the Patagonian surface and probably they may not be captured by global models due to their localized features.