Blue-ice area

Such blue-ice areas typically form when the movement of both air and ice are obstructed by topographic obstacles such as mountains that emerge from the ice sheet, generating particular climatic conditions where the net snow accumulation is exceeded by wind-driven sublimation and snow transports.

Blue-ice areas have a generally smooth and often[1] rippled appearance, a blue colour[2] and a sparseness of bubbles in the ice.

[7] This is because most aerodynamic drag is caused by surface anomalies less than a centimetre long, not larger uneven forms.

[8] The occurrence of supraglacial moraines at blue-ice areas has been reported;[9] these form when debris contained within a glacier accumulates at the surface due to melting or sublimation.

[18] Individual locations in Antarctica include areas of the Allan Hills,[11] the Queen Fabiola Mountains (the Yamato ice field there covers an area of 4,000 square kilometres (1,500 sq mi) and is the largest such structure),[19] Scharffenberg-Botnen[20] and the Sør Rondane Mountains.

[8] Blue-ice areas are regions where more snow is removed by sublimation or by wind than accumulates by precipitation or wind-driven transport,[2] leading to the emergence of (blue) ice.

[12] Such areas exist even in the coldest parts of Antarctica,[2] and they are characterized by high mean wind speeds and low precipitation.

[19] Once they have formed, the smooth surface prevents snow from accumulating as it is quickly blown away by the wind, and the blue colour increases the absorption of sunlight and thus sublimation; both these phenomena act to maintain the blue-ice area, and wind-driven transport of warm air can cause the blue-ice area to expand downwind.

Presumably, irregular surface topography obstructs ice flow and locally creates atmospheric conditions suitable for the development of blue-ice areas.

[9] Changes in mean wind speeds cause short-term fluctuations in the land covered by blue-ice areas.

This also led to increased research in the glaciological[2] and dynamical properties of blue-ice areas, and later to their meteorological and climatological implications.