New Delhi: Pine Island Glacier witnessed the blowing snow and sea smoke this October, which was an exceptional occurrence recorded by the Landsat 8 satellite. Having been one of the glaciers that is rapidly receding, Pine Island Glacier is situated in the West Antarctic Ice Sheet and calving ice into the Amundsen Sea. Although the glacier is famous for huge iceberg production, this month’s event was centred on marginally shallow water meteorological phenomena associated with winds blowing over the glacier front and surrounding waters.
NASA glaciologist Christopher Shuman from the University of Maryland, Baltimore County said that “sea smoke” is formed when cold air from Antarctica rushes over warmer water. Here, winds forced the sea ice offshore and consequently, slightly warmer water rose from the bottom. If cold air blew across this warmer water, water vapour quickly formed frost into thin ice crystals, which resembled smoke floating above the water surface.
Because of the clear skies that prevailed on October 10, this phenomenon that is usually obscured by clouds was observable. From the image captured by the Operational Land Imager (OLI) on the Landsat 8, sea smoke was observed close to the glacier front and along the northern margin, which provided an excellent view against the background of the glacier.
Blowing snow due to strong katabatic winds
The strong winds blew during the spring and created streams of snow over the ice sheet, which left white lines on the scene. These winds develop from a cold, dense air mass that has been built up in the interior of Antarctica during the winter. These cold air flows are referred to as katabatic winds; they rush downward towards the coast as spring arrives and bring along sudden gusts.
The largest plumes were observed to originate from an especially crevassed zone along the southern margin of Pine Island Glacier, which is a region of jumbled ice. The glaciologist explained that the magnitude and frequency of such winds are critical in the polar climate, acting on snow distribution and sublimation near the coast.
The effect of global warming on Antarctic ice sheets
These strong winds affect blowing snow that in turn affects the surface mass balance of the West Antarctic Ice Sheet. However, the extent to which wind-driven snow loss contributes to the glacier’s overall ice mass over the longer term is uncertain, primarily because of a dearth of field measurements, and problems associated with satellite observations in Antarctica. This beautiful and dramatic spectacle of sea smoke and blowing snow demonstrates the dynamic forces at work in the Antarctic and the glaciers that are so sensitive to them as they extend from the continent into the sea.
