生态学研究
Eddy correlation station provides data for energy balancestudies. (Canada Glacier, Taylor Valley, Antarctica).
The Long-Term Ecological Research (LTER) program, sponsored bythe National Science Foundation, monitors ecological phenomena in arange of environments. The program supports 16 sites in NorthAmerica and two in Antarctica, including the newest site in theMcMurdo Dry Valleys—one of the most extreme deserts on Earth. The McMurdo LTER, headed by Dr. Robert Wharton, Jr. (DRI),is thecoldest and driest site. The study attempts to understand twoprocesses: the influence of physical and biological constraints ondry valley ecosystems, and the effects of material transport onthese ecosystems. All ecosystems are shaped by climate and materialtransport, but no where is this more apparent than in the dryvalleys. During a few summer weeks, temperatures breach thefreezing mark and glacial melt feeds ephemeral streams andperennially ice-covered lakes. This period is essential tosustaining life because most material transport (organic carbon,nutrients, and sediments) occurs during this time.
生态学研究
Weather station sites in the McMurdo Dry Valleys, Antarctica.
Biota that persist in this harsh environment are not evident tothe casual observer. Microscopic plants and organisms findrefuge in small melt pools on the glaciers(cryoconite holes),onbeds of ephemeral streams, in ice-covered lakes, and in the soil.
One of the study’s first steps was to establish a dataacquisition network to document the complex interactions betweenthe biological and physiochemical environments.
Harsh weather conditions in the dry valleys offer uniquechallenges for data collection. Equipment must surviveextreme temperatures and winds, a four-month absence of solarpower, and extended periods without maintenance. Further more, thediverse weather conditions require a weather network, as opposed toa single station common at other LTER sites.
By the completion of our third field season (February 1996),wewill be operating 11 Campbell Scientific meteorological stationsthat comprise the McMurdo LTER Automatic WeatherNetwork(LAWN). Six of these stations are located on lakeshores, and four are mounted on wooden stilts on local glaciers,including an eddy correlation station that aids in energy balancestudies.
McMurdo LTER also operates CR10-based systems that continuouslymeasure:
•level, temperature, and conductivity in three ice-coveredlakes.
•discharge, conductivity, and temperature in 14 streams.
•soil temperature at various depths in a warmingexperiment.
In all, the McMurdo LTER operates more than 30 CR10s and two21Xs.
In the future, the stations will transmit real-time data toMcMurdo Station (~100km east) for access via the Internet. This data will help us plan repairs and upgrades, and will be usedto compare Radars at (Canadian satellite recently launched) imagerywith surface conditions.