Alaska tidewater glacier terminus positions, 1948-2012
2014 (English)In: J GEOPHYS RES-EARTH, ISSN 2169-9003, Vol. 119, no 2, 153-167 p.Article in journal (Refereed) Published
A significant portion of the world's glacier ice drains through tidewater outlets, though much remains unknown about the response to recent climate change of tidewater glaciers. We present a 64 year record of length change for 50 Alaska tidewater glaciers. We use U.S. Geological Survey topographic maps to provide a base length for glaciers before 1970. Using all available cloud-free Landsat images, we manually digitize calving front outlines for each glacier between 1972 and 2012, resulting in a total of more than 10,000 outlines. Tidewater glacier lengths vary seasonally; focusing on the 36 glaciers terminating in tidewater throughout the study period, we find a mean ( standard deviation) seasonal variation of 60 85m a(-1). We use these oscillations to determine the significance of interannual changes in glacier length. All 36 glaciers underwent at least one period (1 year) of significant advance or retreat; 28 glaciers underwent at least one period of both significant advance and retreat. Over the entire period 1948-2012, 24 of these glaciers retreated a total ( uncertainty) of 107.950.29 km, 11 advanced a total of 7.71 +/- 0.20, and one (Chenega Glacier) did not change significantly. Retreats and advances are highly variable in time; several glaciers underwent rapid, short-term retreats of a few years duration. These retreats occurred after large changes in summer sea surface temperature anomalies; further study is needed to determine what triggered these retreats. No coherent regional behavior signal is apparent in the length record, although two subregions show a coherence similar to recent observations in Greenland. Key Points <list list-type="bulleted"> <list-item id="jgrf20191-li-0001">Alaska tidewater glacier length record, 1948-2012 <list-item id="jgrf20191-li-0002">Tidewater glacier retreat not constant in time <list-item id="jgrf20191-li-0003">Some retreats appear to be triggered by changes in ocean temperature
Place, publisher, year, edition, pages
2014. Vol. 119, no 2, 153-167 p.
tidewater glaciers, Alaska, glacier change
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:uu:diva-227209DOI: 10.1002/2013JF002915ISI: 000333032300005OAI: oai:DiVA.org:uu-227209DiVA: diva2:729677