Arctic Field Projects
Project Title: Black carbon in Arctic snow and ice and its effect on surface albedo (Award# 0612636)
PI: Warren, Stephen G (sgw@atmos.washington.edu)
Phone: (206) 543.7230
Institute/Department: U of Washington, Department of Atmospheric Sciences
IPY Project? YES
Funding Agency: US\Federal\NSF\OD\OPP\ARC\ANS
Program Manager: Dr. William Wiseman (wwiseman@nsf.gov)
Discipline(s): | Cryosphere | Meteorology and Climate |
Science Summary:
Small light-absorbing carbonaceous particles ("black carbon", BC) are produced by incomplete combustion in burning of fossil fuels or biomass. The particles are often carried for several days by the atmosphere before being scavenged by raindrops or snow crystals. Radiative transfer modeling and previous published measurements indicate that parts-per-billion amounts of BC can reduce snow albedo significantly, potentially affecting the Arctic climate and the stability of sea ice. BC in snow and ice has recently been identified as one of the largest uncertainties in estimates of global radiative forcing for climate change, because of inadequate knowledge of the BC concentrations. In previous work, the BC content of snow on land and sea in the western Arctic was measured in 1983-4, suggesting possible reductions of albedo of 0-4%. However, there are indications from measurements in 1998 at the SHEBA location that snow in the Arctic Ocean may now be less polluted than 20 years ago. In this project an updated and more comprehensive survey will be undertaken, covering the eastern Arctic as well. Samples will be taken during March-May (i.e., near the time of maximum snow depth) on the Arctic Ocean, in tundra areas of Russia, Alaska, and Canada, in both wet-snow and dry-snow zones of the Greenland Ice Sheet, and on ice caps in Iceland. Glacier ice will be sampled in summer in the ablation zone of the Greenland Ice Sheet; there is evidence that its albedo is reduced by BC as well. Snow samples will be taken at several vertical levels through the snowpack. Snow samples will be collected by project personnel and also by volunteer researchers engaged in other projects at remote field camps. The snow will be melted and filtered; the filters will then be analyzed for light transmission as a function of wavelength, to separate the contributions to absorption by BC and soil-dust. The snow must be kept frozen until immediately before filtering, to avoid losses of BC to the container walls and to avoid algal growth; therefore, much of the analysis will be done near the collection sites. At one or more locations snow samples will be collected over the course of the melting season, to document the vertical redistribution of BC. BC is usually hydrophobic, so as the snow melts it may tend to concentrate at the surface, where it has a greater effect on albedo than if uniformly distributed. Spectral albedo will also be measured at some locations to relate the BC concentrations to their radiative effects. The effect of BC on the surface albedo will be estimated both regionally and seasonally, for use in climate modeling. Air sampling concurrent with snowfall events will be carried out at one or more locations, to determine the scavenging ratio, which is needed in atmospheric transport models that link emissions of aerosols to deposition in precipitation.
Logistics Summary:
With this project, researchers will collect snow to measure black carbon over a wide geographical swath of the Arctic. Information will update and make more comprehensive a 1984 survey of the soot content of snow on land and sea in the western Arctic. During the time of maximum snow depth, researchers will collect samples from arctic tundra, glacier ice, and sea-ice environments in Russia, Alaska, Canada, Greenland, Iceland and the Arctic Ocean. At times, cooperating researchers will collect the samples for this project's researchers; the samples will be kept frozen until the researchers can retrieve them. For other locations, the researchers will themselves travel to the research sites, collect the samples, and analyze them in the field. In 2006, a team of two will participate in an August GEUS-sponsored research campaign in Northeast Greenland. In 2007, three researchers will travel to Svalbard in March for a methods-intercomparison with a Scandinavian group, hosted by the Norwegian Polar Institute. Later that spring, two researchers will travel to Russia, where, accompanied by two Russian collaborators, they will sample snow at: Nar'yan Mar, Vorkuta, Khatanga, and Dikson. Samples will also be collected by Matthew Sturm in March-May during his snowmachine traverse across Canada and will be analyzed by Grenfell, as well as samples collected from North Pole. In summer, Warren will work in western Greenland to analyze samples collected at various AWS sites at Summit and above Thule. Warren will also collect snow near Raven Camp. All samples will be analyzed in the laboratory at Kangerlussuaq. During 2008, a researcher will conduct a spring campaign in Barrow, Alaska, hosting 4 Scandinavian collaborators. In addition, two UW researchers will collect and analyze snow in eastern Siberia in March-May: Yakutsk, Tiksi, Cherskii, Bilibino, Pevek. Two UW researchers will collect snow in three pits south of Camp Raven, at the Dye-2 site, in July, and analyze the samples in Kangerlussuaq. For 2009, a team of 3 will spend about 12 days in April/May sampling snow on the arctic islands of Canada, based a few days at each of four locations: Inuvik, Cambridge Bay, Igloolik, and Resolute. They will access their study sites via fixed-wing aircraft, on day-long round trips from each base. In Russia, the team’s collaborators will manage all sampling activities. In 2010, two researchers will work at Barrow to monitor the vertical redistribution of soot during the snowmelt process, for approximately two weeks in May. They will drive snowmobiles daily to Elson Lagoon, 10-20 km east of Barrow, for sampling. Meanwhile, Russian collaborators will finish the sampling at Tiksi. In mid-July, a team of three will travel to Greenland for field work at Raven Camp. After arriving Kangerlussuaq via the ANG logistics chain, the team will fly via ANG to Raven Camp. There, they will use snowmobiles to access sampling sites near the Dye-2 site. When this work is finished a bit more than a week later, the three will return to Kangerlussuaq and two will depart (one via ANG to Scotia, NY; one via commercial air to Copenhagen) while the PI will stay at Kangerlussuaq to analyze samples in the lab before departing via ANG.
For 2010: In Alaska, CPS will subcontract with BTS to provide (via on-the-ground logistics suppliers): rooms, meals, vehicle rentals, lab and work spaces, limited field gear, bear guards and guides. In Greenland, CPS will provide ANG coordination for passengers and cargo between New York and Raven Camp, user days in Kangerlussuaq and at Raven Camp, snowmachines and communications gear. All other logistics, including commercial travel on the return from Greenland, will be provided by the researchers from the grant.
| Season | Field Site | Date In | Date Out | #People |
| 2006 | Greenland - Kronprins Christian Land | 2 | ||
| 2007 | Greenland - Kangerlussuaq | 07 / 19 / 2007 | 08 / 13 / 2007 | 1 |
| 2007 | Norway - Svalbard | 03 / 22 / 2007 | 04 / 03 / 2007 | 3 |
| 2007 | Russia - Dikson Island | 05 / 03 / 2007 | 05 / 08 / 2007 | 4 |
| 2007 | Russia - Khatanga | 04 / 20 / 2007 | 04 / 28 / 2007 | 4 |
| 2007 | Russia - Nar'yan-Mar | 03 / 28 / 2007 | 03 / 31 / 2007 | 4 |
| 2007 | Russia - Noril'sk | 04 / 28 / 2007 | 05 / 03 / 2007 | 4 |
| 2007 | Russia - Vorkuta | 04 / 02 / 2007 | 04 / 07 / 2007 | 4 |
| 2008 | Alaska - Barrow | 04 / 12 / 2008 | 04 / 22 / 2008 | 6 |
| 2008 | Greenland - Kangerlussuaq | 07 / 21 / 2008 | 08 / 02 / 2008 | 2 |
| 2008 | Greenland - Raven | 07 / 23 / 2008 | 07 / 28 / 2008 | 2 |
| 2008 | Russia - Cherskii | 04 / 21 / 2008 | 04 / 30 / 2008 | 3 |
| 2008 | Russia - Tiksi | 04 / 10 / 2008 | 04 / 20 / 2008 | 3 |
| 2008 | Russia - Yakutsk | 04 / 01 / 2008 | 05 / 10 / 2008 | 3 |
| 2009 | Canada - Cambridge Bay, Victoria Island | 04 / 25 / 2009 | 05 / 09 / 2009 | 3 |
| 2009 | Canada - Igloolik | 04 / 25 / 2009 | 05 / 09 / 2009 | 3 |
| 2009 | Canada - Inuvik | 04 / 25 / 2009 | 05 / 09 / 2009 | 3 |
| 2009 | Canada - Resolute, Cornwallis Island | 04 / 25 / 2009 | 05 / 09 / 2009 | 3 |
| 2010 | Alaska - Barrow | 05 / 20 / 2010 | 06 / 12 / 2010 | 2 |
| 2010 | Greenland - DYE-2 | 07 / 20 / 2010 | 08 / 18 / 2010 | 3 |
| 2010 | Greenland - Kangerlussuaq | 07 / 19 / 2010 | 08 / 19 / 2010 | 4 |
| 2010 | Greenland - Raven | 07 / 20 / 2010 | 08 / 18 / 2010 | 3 |
| 2010 | Russia - Tiksi | 0 |
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