About the August, 2014 dark Greenland photos
29 October, 2014
What we know, the southern Greenland ice sheet hit record low reflectivity in the period of satellite observations since 2000 due to a ~2 month drought affecting south Greenland….
Snowfall summer 2014 for south Greenland would have kept the melt rates down by brightening up the surface. Summer 2014, at the PROMICE.org QAS_A site, we recorded ice loss from the surface at a place we thought was above equilibrium line altitude, where the surface would lose no ice in an ‘average climate’. The higher than normal melt rates allowed the impurities to concentrate near the surface in a process documented for snow surfaces by Doherty et al. (2013).
To avoid misinterpretation, black carbon is only part of the darkness, the rest is dust and microbes (See Dumont et al. 2014 and Benning et al. 2014). The photos are from the lowest part of the ice sheet’s elevation. The upper elevations do not get nearly this dark. This satellite image illustrates for west Greenland how dark the surface gets, down to 30% reflectivity.
- Benning, L.G. A.M. Anesio, S. Lutz & M. Tranter, Biological impact on Greenland’s albedo, Nature Geoscience 7, 691 (2014) doi:10.1038/ngeo2260
- Doherty, S. J., T. C. Grenfell, S. Forsstro¨ m, D. L. Hegg, R. E. Brandt, and S. G. Warren (2013), Observed vertical redistribution of black carbon and other insoluble light-absorbing particles in melting snow, J. Geophys. Res. Atmos., 118, 5553–5569, doi:10.1002/jgrd.50235.
- Dumont, M., E. Brun, G. Picard, M. Michou, Q. Libois, J-R. Petit, M. Geyer, S. Morin and B. Josse, Contribution of light-absorbing impurities in snow to Greenland’s darkening since 2009, Nature Geoscience, 8 June, 2014, DOI: 10.1038/NGEO2180
This lecture is from January, 2013