| NSF Org: |
OPP Office of Polar Programs (OPP) |
| Recipient: |
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| Initial Amendment Date: | September 14, 2010 |
| Latest Amendment Date: | September 14, 2010 |
| Award Number: | 1022996 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Neil R. Swanberg
OPP Office of Polar Programs (OPP) GEO Directorate for Geosciences |
| Start Date: | September 15, 2010 |
| End Date: | August 31, 2013 (Estimated) |
| Total Intended Award Amount: | $190,000.00 |
| Total Awarded Amount to Date: | $190,000.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
51 COLLEGE RD DURHAM NH US 03824-2620 (603)862-2172 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
51 COLLEGE RD DURHAM NH US 03824-2620 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | ARCSS-Arctic System Science |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.078 |
ABSTRACT
The PIs will make key measurements needed to accurately estimate the direct radiative forcing by aerosols over the central Greenland ice sheet. Sampling will take place over a field season that will occur from the spring through fall of 2011. It will include real-time measurements of aerosol physical and optical properties (size distribution, multi-wavelength scattering, σsp, and backscattering, σbsp, coefficients as well as the multi-wavelength absorption coefficient, σap) needed to estimate the aerosol single scattering albedo, ω, and asymmetry parameter, g. Additional measurements of the wavelength-dependent optical depth, τλ, as well as the spectral surface reflectance, Rs will also be made. These data will serve as input to a radiative transfer model that will be used to estimate the direct aerosol radiative forcing at the surface and top of the atmosphere over Greenland. Sources and source regions of the direct radiative forcing will be determined by the chemical composition of the aerosols sampled. It is hypothesized that dust, biomass burning and fossil fuel combustion aerosols often exert a positive direct radiative forcing many times greater than that of anthropogenic greenhouse gases. Additional characterization of snow albedo, which varies occurs on timescales of hours to days, will be made to determine whether it, too, exerts a significant influence on the direct aerosol forcing over Summit. Surface snow grain properties and surface snow chemistry will be determined at high temporal frequency to explore the link between the variability in these properties and the surface albedo.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
A key component of the Arctic climate is the Greenland Ice Sheet, which has the potential to dramatically influence sea level depending on the amount of melting that occurs, as well as climate. Observations show that the melt extent of the Greenland Ice Sheet during summer months is increasing, quite likely due to the warming that has taken place across the Arctic. Although a portion of this warming can be attributed to greenhouse gases, there is growing evidence that soot particles from biomass burning and fossil fuel combustion have the potential to warm the air over the Greenland ice sheet.
Our work involved sampling soot in the air and snow over the Greenland ice sheet as well as the surface reflectance, all of which are key parameters that determine whether soot particles are potenially warming the atmospheric above Greenland. Our results indicate that the levels of soot particles reaching Greenland have a significant impact on the amount of the suns energy that is absorbed in the atmosphere, suggesting that the recent warming and snow melt observed in Greenland are in part due to human activities that generate soot particles. In the snow, we found that the levels of soot are so small that they have a very small effect on the amount of sunlight absorbed by the snow (much less than 1% increase compared to pure snow). In fact, we found that dust in the snow absorbed more sunlight than the soot, but even the combined effects of soot and dust were tiny.
An educational aspect of our proposal involved working with local schools in Atlanta and we had a middle school teacher travel with us to Greenland. A rewarding component of our work was interacting with middle school kids, and teaching them about climate change, glaciers, and their importance with respect to a sustainable future.
Last Modified: 12/17/2013
Modified by: Jack E Dibb
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