Rates and Patterns of Shoreline Change Along the Arctic Coast of Alaska: Bering Strait to the U.S. Canadian Border
Abstract
The U.S. Geological Survey has assembled and analyzed rates of historical shoreline change along more than 2500 km of the Alaskan Arctic coast from the Bering Strait to the U.S. Canadian border. Using shoreline positions from 4 eras (1950s, 1980s, 2000s, and 2010), shoreline change rates were calculated every 50 m over 3 time periods: long-term (LT:1950s to 2010s), early short-term (MT; 1950s to 1980s), and late short-term (ST; 1980s-2010s) and summarized by geographic region and shoreline type (exposed, sheltered, mainland, and barrier coast).
Results show that the Arctic coast of Alaska was dominantly erosional from the 1950s to 2010s with 76 percent of transects measuring shoreline retreat. Mean long-term shoreline change rates of -0.8±0.1 m/yr were not significantly different than the short-term: MT: -0.7±0.1 m/yr and ST -0.8±0.1 m/yr. Rates were highly variable, however, ranging from -25 m/yr to +20 m/yr, with extreme rates associated with migration of barrier islands and limited sections of the mainland coast. Shoreline change rates along the Beaufort Sea coast were considerably higher (7 to 15%) and more variable compared to the Chukchi Sea Coast. Shorelines were generally more erosional during the ST compared to the MT along the Beaufort Sea Coast, however, along the Chukchi coast the trend was opposite, with highest mean erosion rates measured during the MT. Increases in mean erosion and accretion rates through time, along with an increase in the percent of the coast accreting, indicate that the coast is eroding more rapidly. This is particularly important on the exposed mainland coast where loss of the permafrost bluff and tundra landscape is permanent and the eroded material is entrained into the littoral system, redistributed, and deposited as more ephemeral and dynamic beach, spit, and barrier island landforms.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C13D1336G
- Keywords:
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- 0702 Permafrost;
- CRYOSPHERE;
- 0710 Periglacial processes;
- CRYOSPHERE;
- 4546 Nearshore processes;
- OCEANOGRAPHY: PHYSICAL;
- 6309 Decision making under uncertainty;
- POLICY SCIENCES & PUBLIC ISSUES