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Neither dust nor black carbon causing apparent albedo decline in Greenland's dry snow zone: Implications for MODIS C5 surface reflectance
Author(s) -
Polashenski Chris M.,
Dibb Jack E.,
Flanner Mark G.,
Chen Justin Y.,
Courville Zoe R.,
Lai Alexandra M.,
Schauer James J.,
Shafer Martin M.,
Bergin Mike
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl065912
Subject(s) - albedo (alchemy) , snow , environmental science , moderate resolution imaging spectroradiometer , atmospheric sciences , greenland ice sheet , spectroradiometer , climatology , reflectivity , geology , meteorology , satellite , ice sheet , geography , oceanography , physics , art , performance art , optics , art history , astronomy
Remote sensing observations suggest Greenland ice sheet (GrIS) albedo has declined since 2001, even in the dry snow zone. We seek to explain the apparent dry snow albedo decline. We analyze samples representing 2012–2014 snowfall across NW Greenland for black carbon and dust light‐absorbing impurities (LAI) and model their impacts on snow albedo. Albedo reductions due to LAI are small, averaging 0.003, with episodic enhancements resulting in reductions of 0.01–0.02. No significant increase in black carbon or dust concentrations relative to recent decades is found. Enhanced deposition of LAI is not, therefore, causing significant dry snow albedo reduction or driving melt events. Analysis of Collection 5 Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data indicates that the decline and spectral shift in dry snow albedo contains important contributions from uncorrected Terra sensor degradation. Though discrepancies are mostly below the stated accuracy of MODIS products, they will require revisiting some prior conclusions with C6 data.