Christine, Article...View of Arctic Temperatures from Drifting Ice..
Otto Yul'evich Schmidt (1891-1956), a well-known explorer in the Arctic, established the first drifting station, called "Severnyipolyus-1" or "North Pole-1", on 21 May 1937; the idea had its roots in a decree signed by Lenin in March of 1921. The purpose of these northern manned stations was to collect data on a variety of geophysical parameters including the relief of the sea-floor, composition and circulation of the water, sea ice, marine biology, magnetic fields, and of course, the climate of the Arctic. As the government-sponsored scientific program advanced in sophistication, measurements were made of the vertical thermal structure of the atmosphere. The initial North Pole-1 station ended its operation in February 1938, and the drifting scientific stations were not fully operational again until the 1950s (Gordienko, 1962).
The stations typically went into service in April when nearly 24 hours of daylight existed, the thickness and rigidity of the ice were at their maximum, and storm activity was at a minimum. The average length of time on the ice for the scientists was one year, but some stations were occupied for more than three years. There were many times when multiple ice stations were floating around in the Arctic. Virtually all stations began their trip north of 75°N and near 170°W to maximize their movement around the pole – the average speed was less than two miles a day.
Station crews typically included a designated leader, a dozen or so scientists, a radio operator, one doctor, one cook, and one mechanic. The members had to be physically fit and most had previous Arctic expedition experience. Many of these hardy scientists found their niche in life and "wintered-over" on numerous missions; one fellow reportedly spent over 30 years of his life afloat in the Arctic!
The official and personal logbooks from the expeditions are full of accounts of the difficulties that members of the drift teams endured. Not only did the Arctic winter climate present dangers day after day with air temperatures sometimes below -40°C (-40°F), but the fractures of the ice could force entire camps to be dangerously relocated under most extreme weather conditions. And of course, there was the psychological demand associated with a long and dark stay on a block of ice with a band of your comrades.
By 1954, the floating stations had "modern" radiosonde equipment capable of tracking balloons sent into the atmosphere. Among other valuable information, the sensing systems provided a measurement of near-surface air temperatures for each day of observation. The meteorological and positional observations were taken each day near 12Z and no entry was permitted in the analyses if taken before 11Z or after 13Z.
The data from the floating observatories were kindly supplied to us via the National Snow and Ice Data Center (NSIDC, 1997). Ice stations NP-3 through NP-31 operated from April 1954 to July 1990; there are 12,884 valid daily observations for our analyses. For each day, the "Arctic" temperature was determined by first establishing average temperature from 75°N to 80°N and then for 80°N to 90°N. The two values were then areally averaged to determine an estimate of daily Arctic temperature; these were then averaged to determine average monthly temperature. All monthly values were converted into anomalies (deviations from normal), and these monthly anomalies were then averaged to determine the annual temperature anomaly for the Arctic. The floating ice stations are obviously imperfect platforms for making a regional temperature measurement, but given the incredible human effort involved, a look at the records should prove interesting.
A plot of mean annual temperature anomalies from 1954 to 1990 is presented in Figure 1, and as seen there, the temperatures actually cooled by a slight amount (0.11°C) over the 37 years of record. Looking exclusively at the dark months of November to February, the record reveals a cooling of twice that amount. Although none of this cooling is statistically significant, there is absolutely no evidence of warming from the floating station record. This finding is in agreement with Kahl et al. (1993a, 1993b) who found no warming in the Arctic troposphere over similar time periods.
Figure 1. Mean annual temperature anomalies (¡C) for the Arctic floating stations: 1954-1990.
Many of the numerical global climate models predict significant warming in the Arctic region, particularly in winter, for a build-up of atmospheric greenhouse gas concentrations. However, as seen in the floating ice records, no overall or winter warming was observed by the scientists over the 1954 to 1990 period of data collection. Although many Soviet observers afloat on the ice must have prayed for warmer temperatures, their prayers remained unanswered, despite the promise of global (and Arctic) warming.
Further Reading
Gordienko, P.A. 1962. "Scientific observations from, and the nature of drift of the 'North Pole' stations." in Problems of the Arctic and Antarctica, A.F. Treshnikov, editor; translated from Russian by J.H. Slep, J.B. Filimonov, and A. Malahoff). Leningrad: Arctic and Antarctic Research Institute, Main Administration of the Northern Sea Route, Ministry of the Navy, USSR, pp. b-1 to b-19.
Kahl, J.D., D.J. Charlevoix, N.A. Zaitseva, R.C. Schnell, and M.C. Serreze, 1993a: Absence of evidence for greenhouse warming over the Arctic Ocean in the past 40 years. Nature, 361, 335-337.
Kahl, J.D.W., M.C. Serreze, R.S. Stone, S. Shiotani, M. Kisley, and R.C. Schnell, 1993b: Tropospheric temperature trends in the Arctic: 1958-1986. Journal of Geophysical Research, 98, 12,825-12,838.
National Snow and Ice Data Center. 1997. "Daily Arctic Rawinsonde Data from Soviet Drifting Ice Stations, NSIDC-0060. Digital data available from nsidc@kyyos.colorado.edu. Boulder, Colorado: National Snow and Ice Data Center, University of Colorado. |
