The most important change in observing practise has been the changeover from manual to automatic observing systems to do many of the routine synoptic observations. This change occurred in the mid-1980's at Halley and Faraday, and more recently also at Signy Island and Rothera Point, and involved the deployment of SCAWS (Synoptic and Climatological Automatic Weather Station) which was replaced in 1992 with MAWS (Modular Automatic Weather Station). Apart from standard checks to the data, e.g. for extreme values, including those due to equipment malfunction, and incorrect codes, the experience of trained meteorological observers as well as further scrutiny of some of the data suggests that the performance of automatic weather stations and instruments after initial installation has been satisfactory. Instruments are regularly and frequently calibrated. Regular on-site monitoring of the performance of SCAWS and MAWS by observers, including comparisons with measurements from standard meteorological equipment, also appears to have prevented systematic errors in measurement (details of error checking that has been systematically carried out on synoptic observations are noted in Appendix A1).
a) Location: 65ø15'S, 64ø16'W; Alt: 11 m
b) Observations: continuous observations from January 1956 to present at 3 hour intervals (8 observations/day).
c) Equipment history: Manual observation for all parameters prior to installation of SCAWS in April 1985. SCAWS in test phase until end of 1985 and replacing manual observations from January 1986. SCAWS replaced by MAWS in March 1992. MAWS PRT is aspirated.
a) Location (as of January 1992): 75ø53'S, 26ø04'W; Alt: 37 m
The station is situated on a moving ice shelf and has been periodically relocated over the recording period. Sites have all been located within about 10 km of the present position.
b) Observations: continuous observations from January 1957 to present at 3 hour intervals (8 observations/day). For the period of testing of SCAWS in 1986 manual 3 hourly observations ("BASYN SYNOP") are available on the database. Data included for other hours in this year is from the automatic equipment.
c) Equipment history: Manual observation for all parameters up to December 1986. Installation of SCAWS in January 1986 and in test phase until end of 1986. SCAWS replaced by MAWS in February 1992. The hourly SCAWS data for 1986 should be treated with caution as it is suspected instruments may have been improperly calibrated. MAWS PRT is aspirated.
a) Location: 67ø34'S, 68ø08'W; Alt: 16 m
b) Observations: continuous observations from March 1976 to present at 6 hour intervals (4 observations/day). Only 2 observations/day (0000 and 1200Z) in 1976. Data gaps in 1976.
c) Equipment history: Manual observation for all parameters prior to installation of MAWS in December 1990. MAWS in test phase until end of 1991 with manual observations of all parameters on the database up to this time.
a) Location: 60ø45'S, 45ø36'W; Alt: 7 m
b) Observations: continuous observations from January 1956 to December 1969 and January 1982 to present. Observations every 3 hours (8 observations/day) in first period and from January 1989, and every 4 hours (4 observations/day) at other times. Data complete up to 1969. Only wind speed, (no wind direction), pressure and temperature from 1982 to 1987. Infrequent cloud and visibility observations from 1988 to present, and gaps in other parameters due to lack of trained observer.
c) Equipment history: Manual observation for all parameters until SCAWS installed in 1988 and replaced by MAWS in 1992.
Jones, P.D. and Limbert, D.W.S. (1989): A data bank of Antarctic surface temperature and pressure data. Office of energy research, Report No. TR038. United States Dept. of Energy, Washington, 52pp. Meteorological Office (1982). Observer's Handbook. 4th Ed., H.M.S.O., London, 220pp.