INVESTIGADORES
GAIERO Diego Marcelo
congresos y reuniones científicas
Título:
Tracing dust sources and transport mechanisms in Southern South America using geochemical, remote sensing and ground observation methods
Autor/es:
GAIERO DM., GASSÓ S AND CHEMALE, F.
Lugar:
Vienna, Austria
Reunión:
Congreso; EGU General Assembly 2008; 2008
Institución organizadora:
European Geosciences Union
Resumen:
Aeolian mineral dust atmosphere is an excellent tracer of the atmospheric circulation
and transport and is often used as proxy indicator of aridity on the continents. There
are different and complementary approaches to track dust mobilization. Satellite imagery
is is used evaluate dust dispersion, transport and the connection between dust
sources and sinks. Visibility observations can be used as a proxy of dust activity in
unpolluted regions when satellite imagery is obstructed by clouds. In addition, one
of the most powerful approaches to evaluate present and past dust provenance transported
from desert areas and deposited elsewhere in the ocean and continents consist
in the characterization of the mineralogical, chemical and isotopic (Sr, Nd and Pb)
composition of dust sources. By linking seasonal sampling of aerosols with thin layers
of dust accumulated in undisturbed lake and marine sediments or ice layers it is
possible to identify rapid changes in sources areas, which can be attributed to seasonal
variability in wind systems, trajectories, and intensity.
In order to evaluate present and paleo-atmospheric circulation and transport in southern
South America (SSA) we have been conducting seasonal dust sampling, satellites
and, ground observations along the Patagonian coast and Central Argentina since
2004. Additionaly, we started a sampling program of surface sediments of the potential
dust source areas (PSA) in SSA (e.g., Puna-Altiplano, Central-West Argentina and
Patagonia). Sediment samples from the different PSA show distinctive isotopic com
position thus allowing tracing back the origin of dust collected at the different dustposition thus allowing tracing back the origin of dust collected at the different dust
monitoring stations. Furthermore, their unequivocal chemical signature allows linking
them with sediments from different continental, marine and ice records in the southern
hemisphere, thus enhancing our understanding on paleo-atmospheric circulation and
on changes in the climatic conditions of the sources.
Our estimation of horizontal fluxes measured along the Patagonian coast is more than
200 times compared to the previously measured and modelled fluxes. Spikes in dust
fluxes are linked to westerly storms producing dust events which typically last for
one day. Satellite imagery reveals dust sources are linked to numerous topographic
lows of largely diverse dimensions ( 10s meter to kilometres) and are widespread
in the Patagonian surface. This suggests that Patagonian dust sources are not well
represented in global models.
in the Patagonian surface. This suggests that Patagonian dust sources are not well
represented in global models.
10s meter to kilometres) and are widespread
in the Patagonian surface. This suggests that Patagonian dust sources are not well
represented in global models.