The geodetic mass balance of Eyjafjallajokull ice cap for 1945-2014: processing guidelines and relation to climate

摘要

Mass-balance measurements of Icelandic glaciers are sparse through the 20th century. However, the large archive of stereo images available allows estimates of glacier-wide mass balance ((B) over dot) in decadal time steps since 1945. Combined with climate records, they provide further insight into glacier-climate relationship. This study presents a workflow to process aerial photographs (1945-1995), spy satellite imagery (1977-1980) and modern satellite stereo images (since 2000) using photogrammetric techniques and robust statistics in a highly automated, open-source pipeline to retrieve seasonally corrected, decadal glacier-wide geodetic mass balances. In our test area, Eyjafjallajokull (S-Iceland, similar to 70 km(2)), we obtain a mass balance of (B) over dot(1945)(2014) = -0.27 +/- 0.03 m w.e.a(-1), with a maximum and minimum of (B) over dot(1984)(1989) = 0.77 +/- 0.19 m w.e.a(-1) and (B) over dot(1994)(1998) = -1.94 +/- 0.34 m w.e.a(-1), respectively, attributed to climatic forcing, and (B) over dot(2009)(2010) = -3.39 +/- 0.43 m w.e.a(-1), mostly caused by the April 2010 eruption. The reference-surface mass balances correlate with summer temperature and winter precipitation, and linear regression accounts for 80% of the mass-balance variability, yielding a static sensitivity of mass balance to summer temperature and winter precipitation of - 2.1 +/- 0.4 m w.e.a(-1)K(-1) and 0.5 +/- 0.3 m w.e.a(-1) (10%)(-1), respectively. This study serves as a template that can be used to estimate the mass-balance changes and glaciers' response to climate.