The National Science Foundation's Office of Polar Programs places automatic weather station (AWS) units in remote areas in Antarctica in support of meteorological research, applications, and operations. The basic AWS units measure air temperature, wind speed, and wind direction at a nominal height of 3 meters above the surface. Air pressure is measured at the height of the electronics enclosure. Some units measure relative humidity at 3 meters above the surface and the air temperature difference between 3 meters and 0.5 meters above the surface at the time of installation. The data are collected by the ARGOS Data Collection System on board the National Oceanic and Atmospheric Administration series of polar-orbiting satellites.
The table gives the AWS unit's site name, ARGOS identification number, latitude, longitude, elevation above sea level, site start date, and WMO number for the Global Telecommunications System for AWS units in operation in 1996. The AWS units are grouped together based on the area and are usually related to a single meteorological experiment. Stearns, et al. (1994) and Holmes, et al. (1995) describe the AWS activities during the two previous austral summers.
The AWS units are located in arrays for meteorological experiments and at other sites for operational purposes. Any one AWS may contribute to several experiments and all contribute to operational purposes, especially for preparing weather forecasts for aircraft flights to and from New Zealand and within Antarctica.
Some of the areas supported area:
The 1995-1996 Antarctic field season began on 2 November, 1995 when G. A. Weidner and R. E. Holmes left Madison, Wisconsin for McMurdo Station, Antarctica, arriving on 6 November 1995.
A Twin Otter flight was made to Sandra AWS site on 8 November. The unit was removed completely and AWS 8923 was returned to McMurdo to be repaired and redeployed at another site.
A Twin Otter flight was made on 9 November to Gill AWS site. Unfortunately, the site could not be located. The flight continued to Schwerdtfeger AWS site. One 1.5 m tower section was added and AWS 8913 was removed and returned to McMurdo to be repaired.
Weather prevented aircraft operations until 14 November, when a Twin Otter flight to Elaine site was made. The aerovane was stuck in one direction because of a build up of ice. The aerovane was replaced with a Belfort aerovane. Two boxes of three gel-cell batteries were installed, and the lower delta-T sensor was unburied and raised to a height of 0.7 meters above the snow.
Pegasus North AWS site was visited by snowmobile on 17 November 1995. Two boxes of three gel-cell batteries were installed.
On 18 November, an NSFA helicopter flight was made to Linda AWS site. A Bendix aerovane was installed. Upon return to the lab, it was discovered that the aerovane removed from Linda AWS site was in good working order. Therefore, the problem with the wind direction at Linda site was not the aerovane, but rather some other component. Weather prevented our scheduled return to Linda AWS site on 21, 22, and 23 November.
On 24 November, an NSFA helicopter flight was made to Linda AWS site. AWS 8915 was removed and replaced with AWS 8909. A new 0.9 m boom was installed along with a new lower delta-T unit. The height of the lower delta-T unit was 1.1 m above the snow surface.
Willie Field AWS site was visited by truck on 27 November, 1995. Two boxes of three gel-cell batteries were installed and the station was raised by one 1.8 m tower section. The Ultrasonic Depth Gauge (UDG) data were downloaded from the CR-10 data logger, and the UDG sensor was raised to a height of 1.36 m. The lower delta-T unit was raised to a height of 1.1 m.
G.A. Weidner and R.E. Holmes left McMurdo Station to return to Madison, WI on 30 November.
On 16 December, Dr. Charles Stearns and Jonathan Thom left Madison, WI for the USCG Polar Star in Hobart Tasmania, arriving there on 18 December. The Polar Star left Hobart on 20 December. Two dog house units were assembled for deployment on Young and Scott Islands. The dog house units did not function properly. AWS 8980 transmitted abnormally and no air pressure data was transmitted by 8983, so the trips to the islands had to be cancelled.
On 25 December a USCG helicopter flight was made to D-10 and AWS 8914 was removed and returned to the ship to be repaired. A second flight was made to D-10 and AWS 21364 was installed as well as a new 0.8 m boom equipped with vertical temperature difference and relative humidity sensors. The 1/8 in diameter antenna was replaced with a 1/4 in diameter antenna.
Also on 25 December, USCG helicopter flight was made to Sutton site but it could not be located. A flight was then made to Port Martin site. The tower was leaning and one guy cable was broken. A new guy cable was installed. A flight was also made to Cape Denison and the unit was found in good working order.
A USCG helicopter flight was made to Cape Webb on 26 December. The power supply was disconnected and then reconnected and the station began to cycle normally. A search for a more suitable site for the AWS was done by air but a better site was not located.
On 26 December a USCG helicopter flight was also made to Penguin Point. As with Cape Webb, the power supply was disconnected and then reconnected and the station began to cycle normally. The 1/8 in diameter antenna was replaced with a 1/4 in diameter antenna.
On 28 December, Greig Thompson left Madison, WI for McMurdo Station, arriving there on 4 January, 1996. Stearns and Thom arrived at McMurdo on 6 January. Unfortunately, two of the AWS units that had been left in the lab in McMurdo were not functioning normally when they arrived, limiting the resources thought available for use in West Antarctica and the Ross Ice Shelf. AWS 21356 was transmitting abnormally and AWS 8938 had a problem with the pressure data when the unit was placed in the enclosure. The pressure sensor functioned normally outside of the enclosure.
On 16 January, Stearns, Thompson and Thom left McMurdo Station for Up Stream Bravo. On 17 January, a Twin Otter flight was made to Elizabeth site and AWS 21361 was removed and replaced with new 21361 electronics. The antenna cable did not have the shield soldered to the TNC connector. The aerovane was replaced with a Bendix aerovane and the antenna cable was replaced with one that had the shield soldered to the TNC connector.
On 18 January a Twin Otter flight was made to J.C. site. The power supply was disconnected and then reconnected and the unit began to cycle normally. The malfunctioning wind direction was not checked because of the high wind speed at the time of the site visit. The flight continued on to Erin site, where the antenna cable was replaced with one that had the shield soldered to the TNC connector, but the unit still did not transmit. Because of limited resources, the electronics were not replaced at that time and the party returned to Up Stream Bravo.
Also on January 18, a Twin Otter flight was made to Theresa site. One battery box was not connected to the junction box. The power supply was disconnected and then reconnected and the station began to cycle normally. A second flight to Erin site was then made and AWS 21361 was replaced with 21363. A Belfort aerovane was also installed.
On 19 January, Stearns, Thom, and Thompson returned to McMurdo Station by LC-130.
The two AWS units that were returned to McMurdo from Up Stream Bravo did not have the antenna shield soldered to the connectors. All possible antenna connectors inside and external to the AWS electronics were examined and the shields soldered to the connectors.
On 23 January a Twin Otter flight was made to Marilyn site. The site was raised by clamping two 1.8 m Rohn tower sections to the exposed 2.0 m of Tri-ex tower using two sets of mounting bars. Three nylon rope guys were added as well. Two boxes of three gel-cell batteries were installed as well as a new power junction box and a new solar panel. The boom is now 3.8 m above the snow surface. The 1/8 in diameter antenna was replaced with a 1/4 in diameter one.
On 24 January a Twin Otter flight was made to Gill site and the site was raised in a similar fashion as that at Marilyn.
A Twin Otter flight was made to Schwerdtfeger site on 27 January and AWS 8913 was installed. A Bendix aerovane was installed as well as 2 boxes of three gel-cell batteries and new battery cables.
Using parts from those AWS units returned from Up Stream Bravo, AWS units 8980 and 8983 were repaired. Crew members of the USCG Polar Star installed dog house AWS 8980 at Young Island. Dog house AWS 8983 was not installed at Scott Island because of fog. AWS 8983 will be returned to Seattle for installation at Scott Island during the next field season.
On the Antarctic Peninsula, members of the British Antarctic Survey raised the AWS unit at Uranus Glacier on 28 November and installed AWS 8925 on the Ronne Ice Shelf on 30 November. On 10 December, Ski Hi site was visited and the station was in good working order and did not need to be raised. Members of the Long Term Ecological Research group replaced the batteries at Santa Claus AWS site on 14 January and installed a sea water temperature probe at Bonaparte Point AWS site on 13 February. The sea water temperature probe did not function properly.
Members of IFRTP installed AWS 8989 at Dome-C II on 12 December. On 15 December, Dome-C site was disconnected from the Radioactive Thermonuclear Generator and was connected to batteries. The station ran for approximately 18 days before the batteries were drained of power. AWS 8914 was removed from D-80 and AWS 8916 was installed on 24 January. In early February, AWS 21360 was installed at D-57 and AWS 8986 was installed at D-47. Also, AWS 31264 was removed from D-10 on 21 January and replaced with AWS 8919, but is currently not working.
Plans for next field season are to service sites as necessary that are accessible from McMurdo Station. Three units will be installed in support of meteorological support for McMurdo Station. They will be deployed near Cape Crozier, at Cape Bird, and on the Byrd Glacier neve. A dog house unit (AWS 8983) will be placed on Scott Island.
Units in West Antarctica will be serviced from Siple Dome and two additional units will be installed. One unit will be deployed at Siple Dome in support of S-153, and one unit will be deployed at 81.20S 126.10W for Dr. David Bromwich.
Three units will be service from South Pole Station. Clean Air site will be moved approximately two miles from its current location, along the edge of the clean air sector, and a snow temperature profile to a depth of 16 m will be installed. Henry and Nico sites will be raised. Also, Bonaparte Point, Santa Claus Island, and Racer Rock sites will be serviced by University of Wisconsin personnel from Palmer Station.
We were assisted in Antarctica by Jonathan Thom and Greig Thompson of the Department of Atmospheric and Oceanic Sciences, University of Wisconsin, NSFA-Meteorology, and by the crews of the Twin Otters, LC-130s, NSFA helicopters, USCG helicopters, and the USCG Polar Star. The AWS program is supported by National Science Foundation grant OPP 9419128.
References
Holmes, R.E., G.A. Weidner, and C.R. Stearns. 1995. Antarctic automatic weather stations: Austral Summer 1994-1995. Submitted to Antarctic Journal of the U.S., 30(5).
Stearns, C.R., G.A. Weidner, and R.E. Holmes. 1994. Antarctic automatic weather stations: Austral Summer 1993-1994. Antarctic Journal of the U.S., 29(5), 281-284.