Monthly mean temperature, pressure and wind speed data from a selection Antarctic stations and automatic weather stations for use in climatic research

Data from mobile platforms, such as ships and drifting buoys are not being collected since our goal is to derive time series of data at fixed locations. Surface and upper air data are being collected and the principal statistics derived are monthly and annual means. Daily data will not be provided in order to keep the data set to a manageable size.

With the resources available to the project, it is clearly not possible to collect all the informat ion that could be required by the whole range of investigations into change in the Antarctic. Instead a key set of meteorological variables (surface temperature, mean sea level pressure and surface wind speed, and upper air temperature, geopotential height and wind speed at standard levels) are being assembled and a definitive set of measurements presented for use by researchers.

A lot of stations have been operated in the Antarctic over the years; many for quite short periods. However, our goal here is to provide information on the long time series that can provide insight into change in the Antarctic. So to be included, the record from a station must extend for 25 years, although not necessarily in a continuous period, or be currently in operation and have operated for the last 10 years.

In READER we have chosen to use only data from year-round stations. It is important when using mean data to know the number of observations that were used in computing the means. As disc ussed in the data section, the READER mean monthly values are therefo re colour coded to indicate the percentage of possible observations used in computing each mean.

Metadata are being provided, where possible, to indicate the type of observing systems used to make the measurements, changes of observing site, changes of observing practice etc. The structure of the metadata is deliberately flexible and will vary considerable between stations, depending on what information is available. The READER data set is being disseminated via CD-ROM and through the World Wide Web at antarctica.ac.uk/met/READER/.

The first release of the data set covers the period up to the end of 2000 and contains all the data collected so far. However, there are still a number of significant gaps and it is hoped that these can be filled over the coming years. In particular, we still require more upper air data.

The data set will be kept up to date on a regular basis via the web site and new versions of the CD released periodically.