FROST Data Sets

Data collected during FROST includes:

Conventional surface and upper-air meteorological observations

Conventional surface and upper air observations, ship reports, drifting buoy data and AWS reports are being held in de-coded form in a computer data base at BAS. The GTS data received at Hobart and Bracknell have been merged with non-GTS observations collected after the SOPs. The data can be converted back into WMO coded form for input to re-runs of numerical analysis schemes. The complete set of in-situ observations collected during SOP-1 and SOP-3 are available on the Internet and can be obtained by anonymous FTP from directory /pub/frost at computer bssiaa.nbs.ac.uk. "Quick-look" gifs are available at pub/frost/SOP1 and pub/frost/SOP3, and are conveniently indexed here: sop1 and sop3. The surface synoptic and radiosonde data are in files july_synop.mer and july_ua.mer respectively.

Satellite imagery

The University of Wisconsin-Madison take the 4 km horizontal resolution Global Area Coverage (GAC) infra-red imagery collected by the NOAA polar orbiting satellites and data from the geostationary satellites in real time. From these they produce a polar stereographic composite image of the Southern Hemisphere south of 40o S. The composites are produced every three hours and are available for collection over the Internet via File Transfer Protocol (FTP). BAS hold copies of these images for all three of the SOPs.

The highest resolution meteorological satellite data that are routinely available are the 1 km horizontal resolution Advanced Very High Resolution Radiometer (AVHRR) images provided by the NOAA satellites. These data are broadcast in real-time along with Tiros Operational Vertical Sounder (TOVS) measurements and the automatic weather station observations. The High Resolution Picture Transmission (HRPT) data are currently taken by Palmer, McMurdo, Rothera and Casey stations. Because of the very large volumes of data involved it was decided not to copy all of these HRPT data, but to try and ensure that they would be available to workers via the national archives. The tapes of raw HRPT are therefore held by BAS (Rothera), the Arctic and Antarctic Research Center, Scripps Institution of Oceanography (Palmer and McMurdo) and the Bureau of Meteorology , Tasmania and Antarctic Regional Office, Hobart (Casey, SOP-2 and SOP-3 only).

New forms of satellite data

The new generation of satellite instruments provided data that allowed the production of a number of high level geophysical parameters that were of great value to FROST and which supplemented the limited amounts of in-situ data from the ocean areas. The scatterometers on the ERS-1/2 satellites provided surface wind vectors over the ice-free ocean and therefore showed small-scale circulation features and details of fronts. The scatterometer winds for the three SOPs have been obtained from the European Space Agency and used in the re-analysis of the surface charts.

Passive microwave satellite imagery

Data from the Special Sensor Microwave/Imager (SSM/I) on the US Defense Meteorological Satellite Program satellites have found many applications in the polar regions, both in meteorological and glaciological studies. The raw SSM/I data for the three SOPs are held at BAS and have been used by the University of Bonn to derive a number of products over the ice-free ocean using existing algorithms. These include surface wind speed, integrated water vapour, rain rate and columnar cloud liquid water.

Numerical analyses and forecasts

Numerical analyses and forecasts were obtained from four centres:

- The UK Met. Office who run a 19 level grid point model

- The US  National Center for Environmental Prediction who use a 28 level, global spectral model with a triangular truncation at wave number 126.

- The European Center for Medium-range Weather Forecasts who use a 31 level spectral model with a triangular truncation of T213.

- The Australian Bureau of Meteorology who run the Global Assimilation and Prediction (GASP) model that 19 levels and a rhomboidal truncation of R53.

Other data

In addition to the meteorological data, other fields of related parameters are being archived. These include the charts of sea ice extent and concentration produced by the NOAA/US Navy Fleet Weather Facility (FLEWEAFAC) National Ice Center (formerly the Joint Ice Center) and sea surface temperatures from the Australian Bureau of Meteorology .

Information on accessing FROST data can be obtained from John Turner (email J.Turner@BAS.AC.UK).