Written by Thomas Zwinger.

Study of interaction between katabatic storms and blue ice areas

Blue ice areas (BIAs) cover about 1% of the glaciated area of the Antarctic ice sheet. At higher altitude they exist because of reoccurring meteorological conditions that clear the ice surface from its snow or firn cover in a consistent and frequent manner.

Katabatic front above the blue ice area

BIAs, hence, can be very constant features and - by their flow properties - potentially also act as a source for easily accessible ice-core climate records in less interior regions of the ice-sheet. By using Elmer as a CFD code the authors investigate the interaction of a katabatic storm front with the ice surface at the high-elevation BIA at Scharffenberbotnen, Dronning Maud Land, Antarctica. The simulations were performed using the variatonal multi-scale (VMS) method in Elmer in a CFD-like simulation of the air-flow above the terrain. The main finding was that the present day geometry of the surrounding nunataks at the valley redirect the fast turbulent air flow exactly towards the region of the inner BIA. A simulation run on a modified terrain resembling the higher ice thickness (and smoother surface) at the Late Glacial Maximum revealed that this effect of redirection of the wind-impact occurred only after the lowering of the ice sheet.

 

Zwinger, T., T. Malm,  M. Schäfer, R. Stenberg, and J.C. Moore, 2015. Numerical simulations and observations of the role of katabatic winds in the creation and maintenance of Scharffenbergbotnen blue ice area, Antarctica, The Cryosphere, 9, 1415-1426, doi:10.5194/tc-9-1415-2015 [link to paper]