Nearshore oceanographic observations at Drew Point, Alaska, Summers 2009 and 2010

The Arctic climate is changing, inducing accelerating retreat of ice-rich permafrost coastal bluffs. Along Alaska’s Beaufort Sea coast, erosion rates have increased roughly threefold from 6.8 to 19 m per yr since 1955 while the sea ice-free season has increased roughly twofold from 45 to 100 days since
1979. We develop a numerical model of bluff retreat to assess the relative roles of the length of sea ice-free
season, sea level, water temperature, nearshore wavefield, and permafrost temperature in controlling
erosion rates in this setting. The model captures the processes of erosion observed in short-term
monitoring experiments along the Beaufort Sea coast, including evolution of melt notches, topple of ice
wedge-bounded blocks, and degradation of these blocks. Model results agree with time-lapse imagery
of bluff evolution and time series of ocean-based instrumentation. Erosion is highly episodic with 40% of
erosion is accomplished during less than 5% of the sea ice-free season. Among the formulations of the
submarine erosion rate we assessed, we advocate those that employ both water temperature and nearshore
wavefield. As high water levels are a prerequisite for erosion, any future changes that increase the frequency
with which water levels exceed the base of the bluffs will increase rates of coastal erosion. The certain
increases in sea level and potential changes in storminess will both contribute to this effect. As water
temperature also influences erosion rates, any further expansion of the sea ice-free season into the
midsummer period of greatest insolation is likely to result in an additional increase in coastal retreat rates.
This dataset includes observations of water level, water temperature, and wave field collected in 2009 and 2010 near Drew Point, AK by investigators Anderson, Overeem, and Wobus, with help from Adam LeWinter. This data was used in a publication published in 2014 by Barnhart et al. Barnhart, K. R., R. S. Anderson, I. Overeem, C. Wobus, G. D. Clow, and F. E. Urban (2014), Modeling erosion of ice-rich permafrost bluffs along the Alaskan Beaufort Sea coast, Journal of Geophysical Research Earth Surface, 119, doi:10.1002/2013JF002845. Platform/Station/Site/Ship Information: A map of the sites can be found in Figure 2 of Barnhart et al. (2014). Exact latitude/longitude locations and temporal durations for each instrument is provided in the attached README.