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Changing surface-at...
Changing surface-atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland
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- Charalampidis, Charalampos, 1983- (författare)
- Uppsala universitet,Luft-, vatten- och landskapslära,Geological Survey of Denmark and Greenland (GEUS),Ice, Climate and Environment
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- van As, Dirk (författare)
- Geological Survey of Denmark and Greenland (GEUS)
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- Box, Jason E. (författare)
- Geological Survey of Denmark and Greenland (GEUS)
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- van den Broeke, Michiel R. (författare)
- Institute for Marine and Atmospheric Research in Utrecht (IMAU)
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- Colgan, William T. (författare)
- Geological Survey of Denmark and Greenland (GEUS)
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- Doyle, Samuel H. (författare)
- Aberystwyth University
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- Hubbard, Alun L. (författare)
- University of Tromsø
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- MacFerrin, Michael (författare)
- Cooperative Institute for Research in Environmental Sciences (CIRES)
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- Machguth, Horst (författare)
- Geological Survey of Denmark and Greenland (GEUS)
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- Smeets, C. J. P. Paul (författare)
- Institute for Marine and Atmospheric Research in Utrecht (IMAU)
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(creator_code:org_t)
- 2015-11-18
- 2015
- Engelska.
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Ingår i: The Cryosphere. - : Copernicus GmbH. - 1994-0416 .- 1994-0424. ; 9:6, s. 2163-2181
- Relaterad länk:
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https://doi.org/10.5...
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https://www.the-cryo...
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https://urn.kb.se/re...
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https://doi.org/10.5...
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Abstract
Ämnesord
Stäng
- We present 5 years (2009-2013) of automatic weather station measurements from the lower accumulation area (1840 m a.s.l. - above sea level) of the Greenland ice sheet in the Kangerlussuaq region. Here, the summers of 2010 and 2012 were both exceptionally warm, but only 2012 resulted in a strongly negative surface mass budget (SMB) and surface meltwater run-off. The observed run-off was due to a large ice fraction in the upper 10 m of firn that prevented meltwater from percolating to available pore volume below. Analysis reveals an anomalously low 2012 summer-averaged albedo of 0.71 (typically similar to 0.78), as meltwater was present at the ice sheet surface. Consequently, during the 2012 melt season, the ice sheet surface absorbed 28% (213 MJ m-2) more solar radiation than the average of all other years. A surface energy balance model is used to evaluate the seasonal and interannual variability of all surface energy fluxes. The model reproduces the observed melt rates as well as the SMB for each season. A sensitivity analysis reveals that 71% of the additional solar radiation in 2012 was used for melt, corresponding to 36% (0.64 m) of the 2012 surface lowering. The remaining 64% (1.14 m) of surface lowering resulted from high atmospheric temperatures, up to a + 2.6 degrees C daily average, indicating that 2012 would have been a negative SMB year at this site even without the melt-albedo feedback. Longer time series of SMB, regional temperature, and remotely sensed albedo (MODIS) show that 2012 was the first strongly negative SMB year, with the lowest albedo, at this elevation on record. The warm conditions of recent years have resulted in enhanced melt and reduction of the refreezing capacity in the lower accumulation area. If high temperatures continue, the current lower accumulation area will turn into a region with superimposed ice in coming years.
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences (hsv//eng)
Nyckelord
- energy balance
- Greenland
- ice sheet
- melt
- albedo
- feedback
- percolation
- refreezing
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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Charalampidis, C ...
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van As, Dirk
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Box, Jason E.
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van den Broeke, ...
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Colgan, William ...
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Doyle, Samuel H.
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visa fler...
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Hubbard, Alun L.
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MacFerrin, Micha ...
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Machguth, Horst
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Smeets, C. J. P. ...
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