Greenland albedo rebounds from snowfall but is again followed widespread high air temperatures

In the latest update of daily Greenland reflectivity (a.k.a., albedo) observed by the NASA MODIS sensors, we see the effect of fresh snow brightening the ice sheet surface after the extreme low albedo in mid July, 2012. Late July’s reflectivity remains below other years in the observational record since 2000 and the values are trending lower again because of the darkening effect of near-surface air temperatures reported for 24-31 July being near or above the melting point, according to ground observations maintained by Konrad Steffen, director of the Swiss Federal Institute for Forest, Snow and Landscape Research. The earlier high melt area episode was 11-15 July, 2012.

Daily ice sheet averaged reflectivity values for 13 individual years beginning in 2000. 0-3200 m refers to the elevation range of the whole ice sheet.

If the 24-31 July high temperatures are on par with those from 11-15 July, 2012 and if there is not another summer snowfall at the higher elevations of the ice sheet, I’d expect the albedos to decline further, reaching say 65.5% in the coming days.

These results are after the externally-reviewed publication Box et al. (2012), citation below.

Work Cited

  • Box, J. E., Fettweis, X., Stroeve, J. C., Tedesco, M., Hall, D. K., and Steffen, K.: Greenland ice sheet albedo feedback: thermodynamics and atmospheric drivers, The Cryosphere, 6, 821-839, doi:10.5194/tc-6-821-2012, 2012. open access

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Reflectivity (a.k.a. albedo) anomaly computed as the July average albedo for 5 km grid cells for the 12 year period (2000-2011) minus July 2012 values. Negative anomaly values mean the ice sheet is darker than average.

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