Extraordinary blowing snow transport events in East Antarctica
In the convergence slope/coastal areas of Antarctica,
a large fraction of snow is continuously eroded and
exported by wind to the atmosphere and into the ocean. Snow
transport observations from instruments and satellite images
were acquired at the wind convergence zone of Terra Nova
Bay (East Antarctica) throughout 2006 and 2007. Snow
transport features are well-distinguished in satellite images and can extend vertically up to 200 m as first-order quantitatively estimated by driftometer sensor FlowCaptTM.
Maximum snow transportation occurs in the fall and winter
seasons. Snow transportation (drift/blowing) was recorded
for*80% of the time, and 20% of time recorded, the flux is
[10-2 kg m-2 s-1 with particle density increasing with
height. Cumulative snow transportation is *4 orders of
magnitude higher than snow precipitation at the site. An
increase in wind speed and transportation (*30%) was
observed in 2007, which is in agreement with a reduction in
observed snow accumulation. Extensive presence of ablation
surface (blue ice and wind crust) upwind and downwind of
the measurement site suggest that the combine processes of
blowing snow sublimation and snow transport remove up to
50% of the precipitation in the coastal and slope convergence area. These phenomena represent a major negative effect on the snow accumulation, and they are not sufficiently taken into account in studies of surface mass balance. The observed wind-driven ablation explains the inconsistency between atmospheric model precipitation and measured snow accumulation value.
Authors: Scarchilli, C., Frezzotti, M., Grigioni, P., De Silvestri, L., Agnoletto, L., Dolci, S.