Katabatic winds

The extreme climate of the ice sheet, in particular in its north central part is dominated by stable high pressure regimes, that are perturbed only from time to time by the passage of depressions.The existence of this anticyclonic sheet is at the origin of a large negative radiation balance and leads to a strong thermal surface inversion. The layers of dense cold air, formed through contact with the ice flow, downward the slope through gravity. 

Originating usually from the center and the crests of the icecap, these diverging fluxes first propagate along the strongest gradient and are then subsequently deviated clock-wise
by the Coriolis force closer to the coasts.
 
The direction and strength of these katabatic winds is strongly linked to the global topography of the ice sheet and the local relief of the mountains and valleys in the coastal areas. In general, these winds are mainly characterized by their:
• constancy in direction,
• temporal periodicity,
• weak average strength.
 
Despite the last parameter, the constancy of the katabatic winds an their direct link to the topography create a favorable frame for the realization of kite supported long distance expeditions.


Model of the katabatic winds. Arrows: direction
and strength at 10m for given date and time. Image:
Heinemann and Klein.

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