Wind speed events and wind direction at Pegasus site
the Italian National Antarctic Research Programme reinstalled the unit at Pat Site. References Keller, L., G. Weidner, C. Stearns, and M. Sievers. 1989. Antarctic automatic weather station data for the calendar year 1988. Madison: University of Wisconsin. Savage, M., and C. Stearns. 1985. The climate in the vicinity of Ross Island, Antarctica. Antarctic Journal of the U.S., 20, 1-8.
Wind speed events and wind direction at Pegasus site during 1989 CHARLES R. STEARNS and GEORGE A. WEIDNER
Department of Meteorology University of Wisconsin Madison, Wisconsin 53706
On 22 January 1989 an automatic weather station unit was installed on the Ross Ice Shelf between the ice shelf edge and White and Black islands at the blue ice region being considered for an aircraft runway (figure 1). The purpose of the automatic weather station unit was to monitor the meteorology of the blue ice region to find out if the site is satisfactory for aircraft operations. The automatic weather station location was 77.97°S 166.49°E near the site of the downed aircraft Pegasus. The unit operated until 11 November 1989 when the it was removed for installation on Mount Erebus. The blue ice in the area of the Pegasus aircraft is unusual when compared to nearby locations such as the present site of Williams Field. The presence of blue ice indicates that at sometime in the past the snow was extensively melted and refrozen to form the blue ice. The depth of the blue ice also indicates that the melting and refreezing may have occurred almost annually. Sublimation and deposition of moisture may occur in the blue ice area. Previous experience has shown that the wind field around obstacles when the vertical static stability of the atmosphere is very high is strongly influenced by the obstacles. On the Ross Ice Shelf near Ross Island, the variation in the horizontal wind flow is largely determined by the obstacles. Examples of the wind flow are shown in Slotten and Stearns (1987) and Stearns and Wendler (1988). The Pegasus automatic weather station unit was equipped with a relative humidity sensor at 3 meters and with thermocouples to measure the vertical temperature difference between the nominal heights of 0.5 and 3.0 meters. Combining the air temperature, vertical air temperature difference, relative humidity and wind speed with appropriate theory of profile structure in the surface layer of the atmosphere estimates can be made of the sensible and latent heat flux from the to the atmosphere. The results show that melting of the snow did not occur during the record period. The maximum air temperature recorded was below zero. The maximum temperature 258
Slotten, H., and C. Stearns. 1987. Observations of the dynamics and kinematics of the atmospheric surface layer on the Ross Ice Shelf, Antarctica. Journal of Climate and Applied Meteorology, 26, 1,731-1,743. Stearns, C. 1988. Automatic weather station project. Antarctic Journal of the U. S., 22, 16-20. Stearns, C., and G. Weidner. 1989. Antarctic automatic weather stations: Austral summer 1988-1989. Antarctic Journal of the U.S., 24, 242-243. Stearns, C., and G. Wendler. 1988. Research results from Antarctic automatic weather stations. Reviews of Geophysics, 26, 45-61.
at Ferrell and Marble Point sites is above freezing in January and December, 1989. Any melting of the snow or ice is most likely to occur during the months of December and January. The table shows that the winter temperatures at Pegasus site are low enough to freeze liquid water on or near the ice surface. The Pegasus Site wind data used for analysis was the 3 hourly observation selected from the complete data set obtained from Service ARGOS on magnetic tape. The wind speed and the wind direction are recorded on the 3 hourly data sets as 0 if the wind speed is less than 0.5 meters per second. The wind direction is sorted into categories 100 wide using intervals of 0
Wind speed events and wind direction at Pegasus site during 1989 CHARLES R. STEARNS and GEORGE A. WEIDNER
Department of Meteorology University of Wisconsin Madison, Wisconsin 53706
On 22 January 1989 an automatic weather station unit was installed on the Ross Ice Shelf between the ice shelf edge and White and Black islands at the blue ice region being considered for an aircraft runway (figure 1). The purpose of the automatic weather station unit was to monitor the meteorology of the blue ice region to find out if the site is satisfactory for aircraft operations. The automatic weather station location was 77.97°S 166.49°E near the site of the downed aircraft Pegasus. The unit operated until 11 November 1989 when the it was removed for installation on Mount Erebus. The blue ice in the area of the Pegasus aircraft is unusual when compared to nearby locations such as the present site of Williams Field. The presence of blue ice indicates that at sometime in the past the snow was extensively melted and refrozen to form the blue ice. The depth of the blue ice also indicates that the melting and refreezing may have occurred almost annually. Sublimation and deposition of moisture may occur in the blue ice area. Previous experience has shown that the wind field around obstacles when the vertical static stability of the atmosphere is very high is strongly influenced by the obstacles. On the Ross Ice Shelf near Ross Island, the variation in the horizontal wind flow is largely determined by the obstacles. Examples of the wind flow are shown in Slotten and Stearns (1987) and Stearns and Wendler (1988). The Pegasus automatic weather station unit was equipped with a relative humidity sensor at 3 meters and with thermocouples to measure the vertical temperature difference between the nominal heights of 0.5 and 3.0 meters. Combining the air temperature, vertical air temperature difference, relative humidity and wind speed with appropriate theory of profile structure in the surface layer of the atmosphere estimates can be made of the sensible and latent heat flux from the to the atmosphere. The results show that melting of the snow did not occur during the record period. The maximum air temperature recorded was below zero. The maximum temperature 258
Slotten, H., and C. Stearns. 1987. Observations of the dynamics and kinematics of the atmospheric surface layer on the Ross Ice Shelf, Antarctica. Journal of Climate and Applied Meteorology, 26, 1,731-1,743. Stearns, C. 1988. Automatic weather station project. Antarctic Journal of the U. S., 22, 16-20. Stearns, C., and G. Weidner. 1989. Antarctic automatic weather stations: Austral summer 1988-1989. Antarctic Journal of the U.S., 24, 242-243. Stearns, C., and G. Wendler. 1988. Research results from Antarctic automatic weather stations. Reviews of Geophysics, 26, 45-61.
at Ferrell and Marble Point sites is above freezing in January and December, 1989. Any melting of the snow or ice is most likely to occur during the months of December and January. The table shows that the winter temperatures at Pegasus site are low enough to freeze liquid water on or near the ice surface. The Pegasus Site wind data used for analysis was the 3 hourly observation selected from the complete data set obtained from Service ARGOS on magnetic tape. The wind speed and the wind direction are recorded on the 3 hourly data sets as 0 if the wind speed is less than 0.5 meters per second. The wind direction is sorted into categories 100 wide using intervals of 0
