May 28, 2013

Variability in the surface temperature and melt extent of the Greenland ice sheet from MODIS

Hall, Dorothy K., Comiso, Josefino C., DiGirolamo, Nicolo E., Shuman, Christopher A., Box, Jason E., Koenig, Lora S.
Geophysical Research Letters
  • Finds a positive trend and two major melt events from 2000 to present using satellite-derived moderate-resolution imaging spectroradiometer (MODIS) ice-surface temperature (IST) of the Greenland ice sheet
  • Finds IST increased by ~0.55 ± 0.44°C/decade, with the greatest increase (~0.95 ± 0.44°C/decade) found in northwestern Greenland where coastal temperatures and mass loss are also increasing and outlet glaciers are accelerating
  • IST shows the highest rates of increase during summer (~1.35 ± 0.47°C/decade) and winter (~1.30 ± 1.53°C/decade), followed by spring (~0.60 ± 0.98°C/decade). In contrast, a decrease in IST was found in the autumn (~−1.49 ± 1.20°C/decade), though the IST trends are not statistically significant with the exception of the trend in northwestern Greenland
  • States that major surface melt (covering 80% or more of the ice sheet) occurred during the 2002 and 2012 melt seasons where clear-sky measurements show a maximum melt of ~87% and ~95% of the ice sheet surface, respectively
  • Finds that in 2002, most of the extraordinary melt was ephemeral, whereas in 2012 the ice sheet not only experienced more total melt, but melt was more persistent, and the 2012 summer was the warmest in the MODIS record (−6.38 ± 3.98°C)
  • Data indicates that major melt events may not be particularly rare during the present period of ice sheet warming