Statement of Purpose:
Over the last two decades, the Greenland Ice Sheet (GrIS) has been losing mass at an alarming rate. From 2003 to 2009, ~50% of the total mass loss was from the southeast region, which exhibits the widest range of outlet glacier behavior_s_ found in any region of the GrIS. Outlet glaciers can be used to examine the changes occurring on the peripheries of the ice sheet. Helheim, Fenris, and Midgard glaciers exhibit different calving rates despite their close proximity within Sermilik fjord. Moreover, available velocity data show that these glaciers have different flow patterns and rates (Rignot and Mouginot, 2012). This study highlights an important application of the Landsat archive: modern changes in outlet glacier behavior. When compared to Helheim and Fenris glaciers, Midgard Glacier has experienced a more extreme net retreat (~16 km from 1972 to 2016). Helheim and Fenris glaciers both exhibited an oscillatory retreat pattern with significantly smaller net retreats (5 km and 3 km, respectively). Understanding these glaciers’ differing behaviors can help us to better predict how the GrIS will react to continued warming.
Description of Data Sets:
All data used to show the calving front positions were obtained from Landsat 1, 5, 7, and 8 satellite images during late spring to late summer months; Landsat imagery was downloaded from the Earth Explorer website between Feb. and Mar. 2016. Color composites were made from bands 6, 5, and 4 for Landsat 1; bands 3, 2, and 1 for Landsat 5 and 7; and bands 4, 3, and 2 for Landsat 8. Landsat 7 images obtained after May 31, 2003 have thick black lines present on the image due to the Scan Line Corrector failing. We used all available, high-quality Landsat imagery for this study. We were able to have the same path/row spatial coverage for most time steps, however some images have different spatial coverage. Images for 1998 and 2000 were mosaicked from two Landsat scenes that were acquired minutes apart. The annotated context/overview image was created in ArcGIS 10.3.1 with a 2016 Landsat 8 432 RGB color composite image, overlaid with velocity data from 2009 [Rignot, E., and J. Mouginot (2012), Ice flow in Greenland for the International Polar Year 2008–2009, Geophys. Res. Lett., 39, L11501, doi:10.1029/2012GL051634]. The velocity data was provided to us by our advisor, Dr. Beata Csatho (firstname.lastname@example.org), who received the data directly from E. Rignot. The photograph of Helheim Glacier (looking NNW) was taken in the field and provided by Dr. Leigh Stearns (email@example.com).