Patterns and Controls of Erosion Along the Coastline of the Barrow Environmental Observatory, Northern Alaska

Erosion along high latitude shorelines are among the highest in the world. With changing climatic conditions the vulnerability of arctic shorelines is increasing as a consequence of longer exposure to ice free seas. The Barrow Environmental Observatory (BEO) is bounded on the east by the 10.7 km long Elson Lagoon shoreline of the Beaufort Sea. The 10.7-km Elson Lagoon section is one of 24 key sites identified under the circumarctic Arctic Coastal Dynamics (ACD) program that is coordinated by the International Permafrost Association (IPA). During 2005 the Joint Committee for the International Polar Year (IPY JC) approved the new project Arctic Circum-Polar Coastal Observatory-Networks (ACCO-Net; Project 90). The Elson Lagoon key site with its shoreline erosion measurements dating back to the late 1940s is a major contributing site to the ACD and ACCO-Net projects. Rates of erosion along the 2 to 4 m high, ice and organic rich permafrost bluffs have been monitored annually at 14 transects since 2002 as part of the Arctic Coastal Dynamics (ACD) program. Continuous, ground-based Differential Global Positioning System (DPGS) surveys have been conducted along the entire length of the BEO coastline in 2003, 2006, 2007, 2008 and 2009. Mean erosion rate from DGPS measurements for the six-year period is at 1.97 m/yr. Only until recently have we been able to compare summer and fall erosion rates by surveying the coastline repeatedly during early and late summer seasons. Early summer surveys were conducted in June before complete sea-ice breakup and in August after bluff exposure to the ice-free lagoon. Analysis for the years 2006 to 2009 show similar total rates of erosion for the entire sampling period, but rates calculated for the Fall were markedly more variable than rates calculated for the summer. This presentation will explore the relative importance of a range of factors such as land cover type, orientation of the coastline to prevailing wind direction, and elevation in controlling erosion.