- 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
from part of NSIDC’s Greenland-today 20 August, 2014 post…
Our colleague Jason Box of the Geological Survey of Denmark and Greenland (GEUS), and graduate student Johnny Ryan of Aberystwyth University spent much of the summer on the western ice sheet at Camp Dark Snow, near Kangerlugssuaq on the Arctic Circle (67 degrees north latitude at 1,010 meters above sea level). The team was investigating the Greenland surface albedo, climate, and surface melting, and how these evolve during summer. As part of the research, they have been using drones (Unmanned Aerial Vehicles, or UAVs) to photograph the surface from low altitude to examine the development of surface structures associated with melting. Strips of images and albedo measurements from the UAV are compared with simultaneous satellite images from the NASA MODIS sensor as an intermediate state to relate ground albedo measurements with that of the entire ice sheet. UAV photos reveal a surface riven with fractures, and drained by ephemeral rivers of melt water. The mid-summer melt surface in this area is pocked with 0.5 to 1 meter-wide (1.5 to 3 feet-wide) potholes with black grit and dust collected at the bottom. This black material is called cryoconite, and is comprised of dust and soot deposited on the surface, and melted out from the older ice exposed by melting. The dark patches are often glued together by tiny microbes.
ps. Professors Alun Hubbard and Niel Snooke at Aberystwyth University deserve a lot of credit for the UAV development.
Arrived yesterday to Kangerlussuaq, west Greenland, now 6 AM, we’re just about out the door in effort to put more numbers on how fire and other factors are affecting Greenland’s reflectivity as part of the Dark Snow Project.
I just received this 27 July, 2014 NASA MODIS satellite image showing wildfire smoke drifting over Greenland ice.
Premier climate video blogger Peter Sinclair is a key component of the Dark Snow Project because of our focus on communicating our science to the global audience. The video below was shot and edited last night quickly as we prepare for a return to our camp a few hours from now.
The video does not comment on the important issue of carbon. So, here’s a quick research wrap-up… Wildfire is a source of carbon dioxide, methane and black carbon to the atmosphere. Jacobson (2014) find that sourcing to be underestimated in earlier work. Graven et al. (2013) find northern forests absorbing and releasing more carbon by respiration due to Arctic warming’s effects on forest composition change. At the global scale, the land environment produces a net sink of carbon, taking up some 10% of the atmospheric carbon emissions due to fossil fuel combustion (IPCC, 2007). Yet, whether northern wildfire is becoming an important source of atmospheric carbon (whether from CO2 or CH4 methane) remains under investigation. University of Wisconsin-Madison researchers find:
“fires shift the carbon balance in multiple ways. Burning organic matter quickly releases large amounts of carbon dioxide. After a fire, loss of the forest canopy can allow more sun to reach and warm the ground, which may speed decomposition and carbon dioxide emission from the soil. If the soil warms enough to melt underlying permafrost, even more stored carbon may be unleashed.
“Historically, scientists believe the boreal forest has acted as a carbon sink, absorbing more atmospheric carbon dioxide than it releases, Gower says. Their model now suggests that, over recent decades, the forest has become a smaller sink and may actually be shifting toward becoming a carbon source.
“The soil is the major source, the plants are the major sink, and how those two interplay over the life of a stand really determines whether the boreal forest is a sink or a source of carbon
- Danish Meterological Institute provided the NASA MODIS satellite image
- Graven, H.D., R. F. Keeling, S. C. Piper, P. K. Patra, B. B. Stephens, S. C. Wofsy, L. R. Welp, C. Sweeney, P.P. Tans, J.J. Kelley, B.C. Daube, E.A. Kort, G.W. Santoni, J.D. Bent, 2013, Enhanced Seasonal Exchange of CO2 by Northern Ecosystems Since 1960, Science: Vol. 341 no. 6150 pp. 1085-1089, DOI: 10.1126/science.1239207
- Climate Change 2007: Working Group I: The Physical Science Basis, IPCC Fourth Assessment Report: Climate Change 2007
- Jacobson, M. Z., 2014, Effects of biomass burning on climate, accounting for heat and moisture fluxes, black and brown carbon, and cloud absorption effects, J. Geophys. Res. Atmos., 119, doi:10.1002/2014JD021861.
A large number of uncontrolled fires are burning across the Canadian NWT. The prevailing flow brings some of that smoke to darken Greenland ice.
via Brian Kahn of Climate Central
“The amount of acres burned in the Northwest Territories is six times greater than the 25-year average to-date according to data from the Canadian Interagency Forest Fire Center.
Boreal forests like those in the Northwest Territories are burning at rates “unprecedented” in the past 10,000 years according to the authors of a study put out last year. The northern reaches of the globe are warming at twice the rate as areas closer to the equator, and those hotter conditions are contributing to more widespread burns.
The Intergovernmental Panel on Climate Change’s landmark climate report released earlier this year indicates that for every 1.8°F rise in temperatures, wildfire activity is expected to double.
We have a team on Greenland ice right now, and until mid August, tasked with measuring the impact of dark particles on ice melt. We are asking for support to increase our abilities to detect smoke landing on Greenland ice. The support will help us afford expanding our laboratory work.