SNOW STUDIES IN ANTARCTICA

摘要

Seasonal distribution of snow at the South Pole and its relationship to stratigraphy was investigated in pits dug beside 4-yr old accumulation stakes. Results show that conventional stratigraphic methods yield thoroughly reliable values of accumulation rates. The bulk of the year's accumulation is deposited as dunes during winter and subsequently transformed into linear sastrugi so that by winter's end the amplitude of the surface relief exceeds the thickness of snow accumulated annually. During the summer these dunes and sastrugi are gradually worn down by sublimation-deflation, which is believed to be the significant factor in the formation of the remarkably uniform stratigraphy ob¬served in pits. An examination of bullet crystals in precipitation indicates that combinations of bullets originate as primary growth structures and that indi¬vidual bullets are formed as a result of the disintegration of these primary growth forms rather than by independent crystallization of pyramidally termi¬nated columns. Three years' measurements of snow accumulation on undulating surfaces around Byrd Station indicate that the undulations are being filled in. These results are discussed in the light of current knowledge of the origin and migration of such features.