Some observations at Halley Bay in seismology, glaciology and meteorology

• Published in: Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 1960
• Subjects: Ice Shelf
• Online Access: http://dx.doi.org/10.1098/rspa.1960.0100; https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.1960.0100

1. Seismology Considerable microseismic activity was observed at Halley Bay during the summer season from December to February, particularly during on-shore winds. Examples of microseismic and wind observations are shown to illustrate the nature of the relation between these two observations. The short-period three-component Willmore seismograph used on the floating ice-shelf was found to record P earth waves from earthquakes at most epicentral distances but S waves were badly recorded. 2. Glaciology The results of elevation, temperature and accumulation studies on the ice-shelf are presented and discussed. These indicate that the ice-shelf was floating with its flat upper surface maintained at 28.6 m above sea level by the yearly addition of about 1 m of snow with a mean density of 0.36 g cm -3 . The results of daily accumulation studies are examined these show that during winter considerable ablation occurred during 24 h and therefore the net accumulation of longer periods may be due to precipitation greatly in excess of the net accumulation. Geomagnetic survey measurements over a small area around the base showed that the coastal features of the ice-front were defined by geological structure beneath the ice-shelf. 3. Meteorology ( a ) The seasonal features of the behaviour of the atmosphere over Halley Bay up to a height of about 20 km are shown and discussed with special reference to wind and tempera­ture changes. A notable feature is the small annual range of monthly mean air temperatures through the troposphere, where extremes are about 10 °C apart, and the increase in the range of mean air temperatures through the stratosphere culminating, at the top of the ascents, in extremes 59.3 °C apart at the 30 mb surface. ( b ) The variation of total and diffuse solar radiation received at Halley Bay on a horizontal surface is examined for dependence on solar elevation, cloud, and drifting snow. With a solar elevation of between 5 and 35°, total solar radiation is within 5 % of 75 % of the estimated ...