Winds in the Coastal Area of Adélie Land Are the Strongest the Wind Conditions There Were Also Extreme, and a Mean Surface Winds Found Anywhere at Sea Level on Earth

Home , Inexpressible Island

Winds in the coastal area to 20 percent, and although this correction might have been overdone according to Loewe (1972), a mean wind speed of of Adélie Land 19.1 meters per second was still calculated. Some 40 years later the French established the station Port Martin (figure 1), approximately 62 kilometers to the west of GERD WENDLER and J.C. ANDRÉ Cape Denison. Here, the wind was recorded 2.4 meters above the roof of a building, about 7.5 meters above the surrounding Geophysical institute ground. However, due to snow drifts, which buried the build- University of Alaska ing, the actual height was less and varied throughout the year. Fairbanks, Alaska 99775-0800 The 2 years of available data have been reported by Boujon (1954), Prudhomme and LeQuinio (1954), and LeQuinio (1956). The winds in the coastal area of Adélie Land are the strongest The wind conditions there were also extreme, and a mean surface winds found anywhere at sea level on Earth. Mawson, annual wind velocity of 17.9 meters per second was found. who was the first to set up camp on this coast, overwintered Because there was no comparison of the instruments, the ex- at Cape Denison, Commonwealth Bay (figure 1) and gave a posure of the instruments differed, and the time of observation vivid description of these winds in his popular book The Home was dissimilar, however, one cannot conclude from the rela- of the Blizzard (Mawson 1915). The winds are now known to tively small difference between each stations mean wind speed, be katabatic, and orographic forcing makes them severe in this which is windier. area (Parish and Wendler 1990). A third station, Dumont dUrville (figure 1), some 64 kilo- Wind velocities were recorded at Cape Denison for February meters west of Port Martin, was established during the mid- 1912 to October 1913 using a Robinson cup anemometer (Ma- 1950s on an island, Ile des Petrels. This island is located about digan 1929; Kidson 1946). The instrument was located on a 2 kilometers from the mainland, and Dumont dUrville is the outcrop which had a height of about 18 meters above the only station for which long-term climatological data are avail- surrounding terrain. After returning from Antarctica, the high able. The mean annual wind speed has been 10.5 meters per wind speeds were doubted because they were unequalled any- second, about half that measured at the other two stations. where on the surface of the Earth, including other parts of The anemometer is located on top of the meteorological ob- Antarctica. A recalibration was carried out at the Aerodyn- servatory, about 10 meters above the ground. amics Laboratory of the University of Melbourne (Basset 1923). The first question to be answered is if the difference in wind The calibration constant for strong winds was reduced by up speed has been caused by the location. The first two stations

138° 141° 144° 147° 150°

JDY EA

66° 66°

Port Martin

67° 67°

- .----

AD ELIE LAN0 C Webb

68° 68° N 100 ...... 0 80KM . -

KING GEORGE LAND 15°Om

69 69° 1380 1410 144° 147° 150° Figure 1. Area map of the Adélie coast.

1990 REVIEW 265 The controversy about which area is really the windiest station, Cape Denison or Port Martin, has never been resolved, and with the existing data set it is still impossible to decide. As part of the U.S.-French program TACO (Interaction At- mosphere Glace Ocean), in austral winter 1989-1990, we placed automated weather stations at Port Martin and Cape Denison. We wanted to place a third station either at Cape de la Motte, west of the Mertz Glacier, or between the Mertz and Ninnis Glaciers (figure 1) but failed due to bad weather and adverse ice conditions. These locations should also have very strong winds according to model simulations (Parish and Wendler 1990). The two stations that were established are located on outcrops, the one at Cape Denison being higher by about 20 meters. At Cape Denison, we were able to find at that place the original site of the anemometer, while the site at Port Martin was moved about 25 meters from its original location. Mawsons hut, which is illustrated in figure 2, is in reasonably good condition for standing in such an environment for nearly Figure 2. Mawsons hut at Cape Denison, Commonwealth Bay (20 80 years. January 1990). The hut was In fairly good shape but full of ice and At the time of writing, 1 full month of data is available. For snow. Note that a storm is coming up, quite suddenly, rather typical Port Martin (figure 3, block A), data from two wind sensors for the area (see Mawsons description). We had just enough time have been analyzed, one a cup and the other a propeller-type to make It back to the boat. anemometer. Two wind sensors were placed at both stations, so that chance of survival throughout the winter is increased. were located on the mainland while the latter was located on It can be seen that the wind speeds follow each other very an island. Hence, an automatic weather station was placed on nicely. For 69.1 percent of the observations, the propeller type the mainland in 1980, some 5 kilometers inland from the edge indicated higher values while for 29.7 percent, the cup type at an altitude of 240 meters. Eight years of data are available had higher ones. for comparison. After making a correction for the recording Looking at Cape Denison (figure 3, block B) it can be seen height—the automatic weather stations height was only 1.5 that the general trend is quite similar to Port Martin. The Feb- meters or so above the surface— agreement within 10 percent ruary 1990 wind speed at Cape Denison was higher than for was found for the mean values of the two stations, which were Port Martin for 71.6 percent of the time. The mean monthly about 10 kilometers from each other. Hence, it can be clearly wind speed suggests Cape Denison is the windier station when stated that the coastal area of Cape Denison-Port Martin is comparing only data points for which simultaneous measure- substantially windier than the Dumont dUrville area. ments were available at both stations. For both stations wind

Port Martin Cape Denison 40 40

35 35

25 . 120

15 Ii

10 5 l L

00 10 15 20 25 0 5 10 15 20 25 Feb 90 Feb. 90

Figure 3. Wind speed for February 1990 for Port Martin (A) (broken line denotes propeller-type anemometer, solid line denotes cup anemometer) and Cape Denison (B).

266 ANTARCTIC JOURNAL February wind speeds at different coastal locations of Adélie Many people helped in the installation of the station. We are Land. Note that the historic observations were taken in thankful to C. Daudon, captain of the LAstrolabe and his different years. crew, the helicopter pilots, numerous personnel from EPF, and especially Robert Flint and Didier Simon, experts for the au- Dumont Port Cape tomatic weather stations. dUrviie D 10 Martin Denison

References February 1990 wind speed a - 8.1 16.0 18.3 Historic wind speeda 11.5 8.9 18.5 14.4 Bassett, W. 1923. Results of test made on a puff ball type anemometer for SIR Douglas Mawson. (Published as Appendix B., by C.T. Madigan Number of years 21 8 2 2 1929.) Boujon, H. 1954. Meteorological observations of Port-Martin in Adélie a In meters per second. Land, Part I. Surface and air observations from 14 February 1950 to 14 January 1951. Daily values and comments. Expeditions Polaires Fran çaises (Scientific Results Series S 5). (In French) Kidson, E. 1946. Australasian Antarctic Expedition, 1911-1914. Sci- speeds in excess of 30 meters per second were observed. In entific Reports, (Ser. B VI). Discussions of observations. general, an increase in wind speed for the month of February LeQuinio, R. 1956. Meteorological observations of Port-Martin in Adé- lie Land, Part I. Surface and air observations from 14 February 1950 is observed. This is typical because February is the month to 14 January 1951. Daily values and additions. Expeditions Polaires when a transition is made from summer to winter conditions Françaises (Scientific Results Series S 5). (In French) with stronger winds during the winter months. In contrast to Loewe, F. 1972. The land of storms. Weather. 27, 110-121. the present findings, historic data (table) show Port Martin Madigan, C.T. 1929. Australasian Antarctic Expedition, 1911-14. Sci- having higher wind speeds in February. Hence, it is impossible entific Reports, (Ser. B. IV). Tabulated and reduced records of the to obtain conclusive evidence which area has more severe wind Cape Denison Station, Adélie Land. speeds. More data will be needed to decide for certain. Mawson, D. 1915. The home of the blizzard, being the story of the Australian Otherwise, the climate is fairly warm for Antarctica: mean antarctic expedition 1911-14. London: Heinemann. temperatures of -6.3 °C at Cape Martin, and -7.7 °C at Cape Parish, T. and G. Wendler. 1990. The katabatic regime at Adélie Land, Antarctica. International Journal of Climatology, 10, 1-10. Denison are typical for the Adélie coast, and the wind hardly Prudhomme, A. and R. LeQuinio. 1954. Meterological observations ever changes direction. Monthly mean "constancy" values of of Port-Martin in Adélie Land, Part II. Atmospheric surface condi- 0.9 are being observed. tions from 15 January 1951 to 20 January 1952. Daily values. Critical This study was supported by National Science Foundation analysis. Expeditions Polaires Françaises (Scientific Results Series S5). (In grant DPP 87-14828 and Expeditions Polaires Francaises (EPF). French)

The katabatic wind regime Parish and Bromwich (1987) have shown that the pattern of near Terra Nova Bay, surface drainage currents over the antarctic continent is highly irregular. In certain portions of the continental hinterland, neg- Antarctica atively buoyant air becomes topographically channeled into "confluence zones," enabling the katabatic winds downstream to become enhanced. The Terra Nova Bay region is one such DAVID H. BROMWICH area (Bromwich and Kurtz 1982; Bromwich 1989a; Parish and Bromwich 1989a). A comprehensive observational study of the Byrd Polar Research Center katabatic wind regime in the vicinity of Terra Nova Bay is Ohio State University currently underway. Observational strategies have included Columbus, Ohio 43210 surface weather data collection from automatic weather stations (Bromwich 1989a), high-resolution satellite imagery anal- yses (Bromwich 1989b), airborne photography (Bromwich, THOMAS R. PARISH Parish, and Zorman 1990), and instrumental aircraft measure- ments (Parish and Bromwich 1989a). An automatic weather Department of Atmospheric Science station has been operating on Inexpressible Island since 1984; University of Wyoming four additional units were deployed at strategic locations in Laramie, Wyoming 82071 and around Terra Nova Bay during the 1987-1988 austral summer in support of this study. In addition, complementary au- ANDREA PELLEGRINI tomatic weather station observations have been collected by the Italian National Antarctic Research Program during this observing period. We are reporting on results from the auto- Comitato Nazionale matic weather station network for the calendar year from Feb- per la ricerca e per lo sviluppo dellEnergia Nucleare ruary 1988 to January 1989; results for parts of this interval are e delle Eneriie Alternative (ENEA) presented by Bromwich and Parish (1988, 1989), Parish and Antarctic Project Bromwich (1989b) and Bromwich et al. (1990). Rome, Italy The figure contains the annual results from the automatic

1990 REVIEW 267