The Antarctic snow accumulation map is derived from a compilation of field measurements. Satellite observations from AMSR-E and AVHRR (Advanced Microwave Scanning Radiometer-EOS and Advanced Very High Resolution Radiometer) instruments are used to guide the interpolation. The effective resolution of the map is approximately 100 km. The estimates of root mean square percentage error apply to regional averages at scales of around 100 km by 100 km. On smaller scales, additional deviations of 30% r.m.s. are likely. Values for locations subject to melt may be unreliable. Units are (kg/m2/a), or (mm/a) water equivalent.
H2O2 (hydrogen peroxide) measurements were made using a HPLC-PCD (high-performance liquid chromatograph) system, between 2004 and 2005. The work was carried out at Halley Station, as part of the Chemistry of the Antarctic Boundary Layer and the Interface with Snow (CHABLIS) project (2001-2006).
Meteorological observations were taken between 2004 and 2005. The work was carried out at the Clean Air Sector Laboratory (Halley, Antarctica) as part of the CHABLIS project (2001-2006).
Measurements of the concentrations of major ions in snow samples, Halley Station, 2004-2005. Snow was collected using surface sampling and snow pits and analysed using ion chromatography. This work was carried out at Halley Station, as part of the Chemistry of the Antarctic Boundary Layer and the Interface with Snow (CHABLIS) project (2001-2006).
Three micro-power Automatic Weather Stations (AWS) with two sonic ranging sensors were deployed at field-sites situated at Rothschild Island, Latady Island and Smyley Island in January 2005. The AWS instruments included a wind vane and two humicaps on the mast and two sonic ranging sensors mounted on separate horizontal scaffold poles. The AWS data collected contributed to a project concerned with understanding how air mass origin and meteorology affect the mass accumulation of snow in areas of the Antarctic Peninsula, and how the atmosphere''s properties are preserved in the snow.
Ground truth measurements in the form of snow/ice cores were obtained from three sites in 2006: Rothschild Island, Latady Island and Smyley Island. The sites selected corresponded to the position of Automatic Weather Stations (AWS) deployed during the previous season. At both the Rothschild Island and Smyley Island sites the AWS - due to an unprecedented amount of snowfall - had been buried. Therefore, two cores, 8m and 12m in length, were obtained from the approximate position of the AWS, in addition to the sampling of a snow pit. At the Latady Island site, the top 60cm of the 5m AWS was protruding above the surface - again, due to an unprecedented amount of snowfall. A diagonally descending trench was dug to recover the AWS and two cores were collected at this site. This work was carried out as part of a project to understand how air mass origin and meteorology affect the mass accumulation of snow in areas of the Antarctic Peninsula, and how the atmosphere''s properties are preserved in the snow, Photographs of the expedition showing the ground layout, the situation of the cores and what was done when they were gathered are available and stored with the data.
Ice cores were drilled at four sites on the Antarctic Peninsula during the 2004-2005 austral summer. Loggers designed to measure the compaction of snow were installed in boreholes, these sensors took a measurement every hour and were sensitive to downward movements of less than a millimetre. Automatic Weather Stations (AWS), sonic snow rangers and thermistor strings were also installed at each site, measuring the snow arriving at hourly intervals. A network of stakes was surveyed by GPS to provide horizontal strain rates, of the glacier, at each location. The flow away from the sites was compared with the snowfall from the ice cores to show up any imbalance. This work was carried out as part of the CVaCS-DECAP project (Correction, Verification and Context, of Satellite-Derived Elevation Changes on the Antarctic Peninsula). The aim of the project was to measure the various factors that affect altitude of snow surfaces in Antarctica, in order to validate data from satellite altimeters. In particular, it aimed for a better understanding of the factors affecting snowpack compaction rates, by accurate measurement of compaction over a period of several years.