Concept information
Preferred term
CLIMATE CHANGE
Definition
- The climate of Alaska has changed substantially over the last 100 years for which direct observations are available. For the last 50 years reliable data are available, while before this time calibration of the instrumentation was spotty, and major breaks in the observations have occurred. During the last 50 years the temperature in Alaska increased by some 3°F (Stafford, Wendler and Curtis 2000, Theoretical and Applied Climatology 67, 33-44), which is about 6 times the worldwide rate of about 1°F per century. This increase varied both in place and time, and seasonally, winter showed the largest increase followed by spring. The temperature increase was not steady over the 50 years; in the mid-seventies a strong temperature increase was observed (Hartmann and Wendler 2005, Journal of Climate, in press). Since then the temperature has not increased, with the exception of the North Slope. This strong, sudden temperature increase indicates that it is due to a circulation change, and at least not directly caused by increased greenhouse gases. We plan to further investigate the climate change, not only for mean values, but also for extremes. Sea ice has decreased in the Southern Beaufort Sea and a good correlation between sea ice concentration and mean annual temperatures of coastal station was observed (Wendler, Moore, Curtis and Stuefer 2002, Proceedings of the 16th IAHR International Symposium, 202-210). This decrease in the sea ice leads to more open water, and during stormy periods, more erosion of the coastline occurs due to more wave action resulting from a longer fetch. There are further some indications that storminess has increased. The increased erosion rate is of great importance for villages at the North and west coast of Alaska, Shishmaref being the most prominent one, but for sure not the only one. We plan to investigate the relationship between temperature, sea ice, storminess and erosion. The surface energy budget for different ice concentration and ice types are proposed to be studied during a cruise in the Arctic Ocean jointly with our Russian colleagues. The observed temperature increase has resulted also in glacier retreat. The mass balance of a glacier is the result of solid precipitation and the melting in summer due to temperatures above the freezing level. Most of the glaciers, and the largest in sice are found in the southern Alaska (Bering and Malaspina Glaciers, Juneau and Harding Ice Fields), where the temperature is much warmer than in the northern Alaska, however, the snow fall is also much higher by a factor of 10. The retreat is especially large in the Brooks Range, where the temperature increase was accompanied by a decrease in precipitation (Curtis Wendler Stone Dutton 1998, International Journal of Climatology 18, 1687-1707). McCall Glacier, studied since the IGY, is a typical example. We propose to investigate the glacier behavior in each of the 3 major mountain ranges as function of the climatic change observed since IGY. There is a good background of selected glaciers since IGY on which our study will concentrate. Summary provided by http://classic.ipy.org/development/eoi/proposal-details.php?id=114 (en)
Broader concept
- A - C (en)
URI
https://gcmd.earthdata.nasa.gov/kms/concept/d91ab3c6-89b0-4748-b824-1e3d45e49049
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