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Contrasting snow and ice albedos derived from MODIS, Landsat ETM+ and airborne data from Langjökull, Iceland

Contrasting snow and ice albedos derived from MODIS, Landsat ETM+ and airborne data from Langjökull, Iceland
Contrasting snow and ice albedos derived from MODIS, Landsat ETM+ and airborne data from Langjökull, Iceland
Surface albedo is a key parameter in the energy balance of glaciers and ice sheets because it controls the shortwave radiation budget, which is often the dominant term of a glacier's surface energy balance. Monitoring surface albedo is a key application of remote sensing and achieving consistency between instruments is crucial to accurate assessment of changing albedo. Here we take advantage of a high resolution (5 m) airborne multispectral dataset that was collected over Langjökull, Iceland in 2007, and compare it with near contemporaneous ETM+ and MODIS imagery. All three radiance datasets are converted to reflectance by applying commonly used atmospheric correction schemes: 6S and FLAASH. These are used to derive broadband albedos. We first assess the similarity of albedo values produced by different atmospheric correction schemes for the same instrument, then contrast results from different instruments. In this way we are able to evaluate the consistency of the available atmospheric correction algorithms and to consider the impacts of different spatial resolutions. We observe that FLAASH leads to the derivation of surface albedos greater than when 6S is used. Albedo is shown to be highly variable at small spatial scales. This leads to consistent differences associated with specific facies types between different resolution instruments, in part attributable to different surface bi-directional reflectance distribution functions. Uncertainties, however, still exist in this analysis as no correction for variable bi-directional reflectance distribution functions could be implemented for the ETM+ and airborne datasets.
Albedo measurement, Landsat, MODIS, Snow, Ice, Glacier, Ice cap, Spatial scales, FLAASH, 6S
0034-4257
183-195
Pope, Ed L.
2043c317-9ba0-4cbb-a47f-a36f9020417e
Willis, Ian C.
3078eb3f-8e81-4d36-9201-e08645141ec5
Pope, Allen
adcf367d-17d9-4d2b-9340-f020570d83fe
Miles, Evan S.
c78ddd34-1513-45ec-810d-f1d9acc6543f
Arnold, Neil S.
39fa17a0-a607-4466-bb55-29c990441c77
Rees, W. Gareth
820e8486-d408-4587-bddc-0a981301a69b
Pope, Ed L.
2043c317-9ba0-4cbb-a47f-a36f9020417e
Willis, Ian C.
3078eb3f-8e81-4d36-9201-e08645141ec5
Pope, Allen
adcf367d-17d9-4d2b-9340-f020570d83fe
Miles, Evan S.
c78ddd34-1513-45ec-810d-f1d9acc6543f
Arnold, Neil S.
39fa17a0-a607-4466-bb55-29c990441c77
Rees, W. Gareth
820e8486-d408-4587-bddc-0a981301a69b

Pope, Ed L., Willis, Ian C., Pope, Allen, Miles, Evan S., Arnold, Neil S. and Rees, W. Gareth (2016) Contrasting snow and ice albedos derived from MODIS, Landsat ETM+ and airborne data from Langjökull, Iceland. Remote Sensing of Environment, 175, 183-195. (doi:10.1016/j.rse.2015.12.051).

Record type: Article

Abstract

Surface albedo is a key parameter in the energy balance of glaciers and ice sheets because it controls the shortwave radiation budget, which is often the dominant term of a glacier's surface energy balance. Monitoring surface albedo is a key application of remote sensing and achieving consistency between instruments is crucial to accurate assessment of changing albedo. Here we take advantage of a high resolution (5 m) airborne multispectral dataset that was collected over Langjökull, Iceland in 2007, and compare it with near contemporaneous ETM+ and MODIS imagery. All three radiance datasets are converted to reflectance by applying commonly used atmospheric correction schemes: 6S and FLAASH. These are used to derive broadband albedos. We first assess the similarity of albedo values produced by different atmospheric correction schemes for the same instrument, then contrast results from different instruments. In this way we are able to evaluate the consistency of the available atmospheric correction algorithms and to consider the impacts of different spatial resolutions. We observe that FLAASH leads to the derivation of surface albedos greater than when 6S is used. Albedo is shown to be highly variable at small spatial scales. This leads to consistent differences associated with specific facies types between different resolution instruments, in part attributable to different surface bi-directional reflectance distribution functions. Uncertainties, however, still exist in this analysis as no correction for variable bi-directional reflectance distribution functions could be implemented for the ETM+ and airborne datasets.

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More information

Accepted/In Press date: 30 December 2015
Published date: 15 March 2016
Keywords: Albedo measurement, Landsat, MODIS, Snow, Ice, Glacier, Ice cap, Spatial scales, FLAASH, 6S
Organisations: Geology & Geophysics

Identifiers

Local EPrints ID: 391996
URI: http://eprints.soton.ac.uk/id/eprint/391996
ISSN: 0034-4257
PURE UUID: 1b496677-8d33-456e-aabf-d22dc806eb12

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Date deposited: 12 Apr 2016 14:17
Last modified: 15 Mar 2024 05:29

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Contributors

Author: Ed L. Pope
Author: Ian C. Willis
Author: Allen Pope
Author: Evan S. Miles
Author: Neil S. Arnold
Author: W. Gareth Rees

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