Assessing spatio-temporal variability and trends in modelled and measured Greenland Ice Sheet albedo (2000–2013)
Accurate measurements and simulations of Greenland Ice Sheet (GrIS) surface albedo are essential, given the role of surface albedo in modulating the amount of absorbed solar radiation and meltwater production. In this study, we assess the spatio-temporal variability of GrIS albedo during June, July,...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2014-12-01
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| Series: | The Cryosphere |
| Online Access: | http://www.the-cryosphere.net/8/2293/2014/tc-8-2293-2014.pdf |
| _version_ | 1828811397197201408 |
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| author | P. M. Alexander M. Tedesco X. Fettweis R. S. W. van de Wal C. J. P. P. Smeets M. R. van den Broeke |
| author_facet | P. M. Alexander M. Tedesco X. Fettweis R. S. W. van de Wal C. J. P. P. Smeets M. R. van den Broeke |
| author_sort | P. M. Alexander |
| collection | DOAJ |
| description | Accurate measurements and simulations of Greenland Ice Sheet (GrIS) surface
albedo are essential, given the role of surface albedo in modulating the
amount of absorbed solar radiation and meltwater production. In this study,
we assess the spatio-temporal variability of GrIS albedo during June, July,
and August (JJA) for the period 2000–2013. We use two remote sensing products
derived from data collected by the Moderate Resolution Imaging
Spectroradiometer (MODIS), as well as outputs from the Modèle
Atmosphérique Régionale (MAR) regional climate model (RCM) and data
from in situ automatic weather stations. Our results point to an overall
consistency in spatio-temporal variability between remote sensing and RCM
albedo, but reveal a difference in mean albedo of up to ~0.08
between the two remote sensing products north of 70° N. At low
elevations, albedo values simulated by the RCM are positively biased with
respect to remote sensing products by up to ~0.1 and exhibit
low variability compared with observations. We infer that these differences
are the result of a positive bias in simulated bare ice albedo. MODIS
albedo, RCM outputs, and in situ observations consistently indicate a
decrease in albedo of −0.03 to −0.06 per decade over the period 2003–2013 for the GrIS ablation area.
Nevertheless, satellite products show a decline in JJA albedo of −0.03 to
−0.04 per decade for regions within the accumulation area that is not
confirmed by either the model or in situ observations. These findings appear
to contradict a previous study that found an agreement between in situ and
MODIS trends for individual months. The results indicate a need for further
evaluation of high elevation albedo trends, a reconciliation of MODIS mean
albedo at high latitudes, and the importance of accurately simulating bare
ice albedo in RCMs. |
| first_indexed | 2024-12-12T09:26:17Z |
| format | Article |
| id | doaj.art-f41adc74b45a4700955490abcd6ba640 |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-12-12T09:26:17Z |
| publishDate | 2014-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-f41adc74b45a4700955490abcd6ba6402022-12-22T00:29:01ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242014-12-01862293231210.5194/tc-8-2293-2014Assessing spatio-temporal variability and trends in modelled and measured Greenland Ice Sheet albedo (2000–2013)P. M. Alexander0M. Tedesco1X. Fettweis2R. S. W. van de Wal3C. J. P. P. Smeets4M. R. van den Broeke5Graduate Center of the City University of New York, 365 5th Ave., New York, NY, 10016 USAGraduate Center of the City University of New York, 365 5th Ave., New York, NY, 10016 USADepartment of Geography, Université de Liège, Place du 20-Août, 7, 4000 Liège, BelgiumInstitute for Marine and Atmospheric research Utrecht, Utrecht University, Princetonplein 5, 3584 CC Utrecht, the NetherlandsInstitute for Marine and Atmospheric research Utrecht, Utrecht University, Princetonplein 5, 3584 CC Utrecht, the NetherlandsInstitute for Marine and Atmospheric research Utrecht, Utrecht University, Princetonplein 5, 3584 CC Utrecht, the NetherlandsAccurate measurements and simulations of Greenland Ice Sheet (GrIS) surface albedo are essential, given the role of surface albedo in modulating the amount of absorbed solar radiation and meltwater production. In this study, we assess the spatio-temporal variability of GrIS albedo during June, July, and August (JJA) for the period 2000–2013. We use two remote sensing products derived from data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS), as well as outputs from the Modèle Atmosphérique Régionale (MAR) regional climate model (RCM) and data from in situ automatic weather stations. Our results point to an overall consistency in spatio-temporal variability between remote sensing and RCM albedo, but reveal a difference in mean albedo of up to ~0.08 between the two remote sensing products north of 70° N. At low elevations, albedo values simulated by the RCM are positively biased with respect to remote sensing products by up to ~0.1 and exhibit low variability compared with observations. We infer that these differences are the result of a positive bias in simulated bare ice albedo. MODIS albedo, RCM outputs, and in situ observations consistently indicate a decrease in albedo of −0.03 to −0.06 per decade over the period 2003–2013 for the GrIS ablation area. Nevertheless, satellite products show a decline in JJA albedo of −0.03 to −0.04 per decade for regions within the accumulation area that is not confirmed by either the model or in situ observations. These findings appear to contradict a previous study that found an agreement between in situ and MODIS trends for individual months. The results indicate a need for further evaluation of high elevation albedo trends, a reconciliation of MODIS mean albedo at high latitudes, and the importance of accurately simulating bare ice albedo in RCMs.http://www.the-cryosphere.net/8/2293/2014/tc-8-2293-2014.pdf |
| spellingShingle | P. M. Alexander M. Tedesco X. Fettweis R. S. W. van de Wal C. J. P. P. Smeets M. R. van den Broeke Assessing spatio-temporal variability and trends in modelled and measured Greenland Ice Sheet albedo (2000–2013) The Cryosphere |
| title | Assessing spatio-temporal variability and trends in modelled and measured Greenland Ice Sheet albedo (2000–2013) |
| title_full | Assessing spatio-temporal variability and trends in modelled and measured Greenland Ice Sheet albedo (2000–2013) |
| title_fullStr | Assessing spatio-temporal variability and trends in modelled and measured Greenland Ice Sheet albedo (2000–2013) |
| title_full_unstemmed | Assessing spatio-temporal variability and trends in modelled and measured Greenland Ice Sheet albedo (2000–2013) |
| title_short | Assessing spatio-temporal variability and trends in modelled and measured Greenland Ice Sheet albedo (2000–2013) |
| title_sort | assessing spatio temporal variability and trends in modelled and measured greenland ice sheet albedo 2000 2013 |
| url | http://www.the-cryosphere.net/8/2293/2014/tc-8-2293-2014.pdf |
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