Tuesday 27 October 1998
From: Matthew Lythe, BEDMAP Database Manager

Data coverage
Since the last update in August the quantity and spatial coverage of data added to the BEDMAP database has increased considerably. At this point in time we have recovered and reformatted in excess of 700,000 ice thickness records from nearly 50 expeditions conducted by national Antarctic programs and universities in Australia, Japan, Germany, Russia, the United Kingdom and the United States. A wide range of data have been incorporated ranging from oversnow seismic traverse data from the International Geophysical Year (IGY) to airborne radar missions conducted in the 1970s to ground based radio echo soundings carried out in the 1995/96 season. For a summary list of the data sets contained to date within the database please visit the BEDMAP web site at; http://www.nerc-bas.ac.uk/public/aedc/bedmap/mission_summary.html
A map showing the coverage of these data sets is also available at this site at;
http://www.nerc-bas.ac.uk/public/aedc/bedmap/bedmap_coverage.html

SPRI/NSF/TUD and BAS radio-echo sounding databases incorporated
Both of these substantial data sets have now been included within BEDMAP. The SPRI based database includes bedrock elevations captured during airborne RES missions flown between 1967 and 1979 by the Scott Polar Research Institute (SPRI) in association with the US National Science Foundation (NSF) and the Technical University of Denmark (TUD). Comprising a data set of over 70,000 values these data cover an area of 7 million square miles. They were the principal data used to prepare the 1983 SPRI Geophysical Folio "The Bedrock Surface of Antarctica". Formatting, validation and integration of the British Antarctic Survey Radio-Echo Sounding Database has also now been completed. This database of digitised airborne radar sounding data holds data for around 280 flights between 1966 and 1988 - over 200,000 measurements. It provides excellent coverage of the Antarctic Peninsula, Ronne Ice Shelf and Ellsworth Land.

JARE ground based RES Data from East Queen Maud Land
We have also now completed the capture of ice thickness data and corresponding descriptive metadata from the Japanese Research Expedition ground based RES missions prior to 1992. Collected in the area inland from the Asuka and Syowa stations, these data include those captured from JARE expeditions 10-11, 23,24,26, and 27 which cover surveys between 1969 and 1988. These data will be complemented in 1999 by the more recent JARE data to be provided by the Department of Applied Physics, Hokkaido University, Japan.

Upcoming activities
The focus will remain on the first phase of work identified at the first BEDMAP workshop, i.e. data collection and storage. This includes the recovery of data, the reformatting of these data to comply with the BEDMAP database format and also evaluation and validation of the data. Validation includes checks for trackline continuity (on oversnow traverse and airborne RES data) and anomalous values. Data sets soon to be incorporated include measurements from the 1951-52 Norwegian-British-Swedish oversnow traverse in Dronning Maud Land, RES data collected in Dronning Maud Land during the 1969 Belgian Antarctic Expedition and a number of airborne RES and seismic data sets collected by the Antarctic Division of Polar Marine Geological Research Expedition (PMGRE), St Petersburg, Russia. We will also be incorporating seismic and radio echo sound data collected by British and US scientists in more recent expeditions.

BEDMAP workshop 2
We would like to propose a second BEDMAP workshop for sometime in April or May 1999. Potentially held in Europe, issues for discussion may include an evaluation the compiled database (including cross-over analysis and refixing procedures and results), evaluation of the best available coastline and bathymetry data, identification of an appropriate geoid model and discussion over the interpolation methods to be used to produce the grid of bed elevation across Antarctica and the continental shelf. The workshop could also specify the final products to be produced by BEDMAP and the work plan to achieve this. This date seems appropriate as it comes towards the end of the first phase of work. We welcome any comments or suggestions relating to the timing, possible location or content of this workshop.