 |
| Titel |
Linking glacier annual mass balance and glacier albedo retrieved from MODIS data |
| VerfasserIn |
M. Dumont, J. Gardelle, P. Sirguey, A. Guillot, D. Six, A. Rabatel, Y. Arnaud |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1994-0416
|
| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 6, no. 6 ; Nr. 6, no. 6 (2012-12-19), S.1527-1539 |
| Datensatznummer |
250003882
|
| Publikation (Nr.) |
 copernicus.org/tc-6-1527-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| Albedo is one of the variables controlling the mass balance of
temperate glaciers. Multispectral imagers, such as MODerate Imaging
Spectroradiometer (MODIS) on board the TERRA and AQUA satellites,
provide a means to monitor glacier surface albedo. In this study,
different methods to retrieve broadband glacier surface albedo from
MODIS data are compared. The effect of multiple reflections due to
the rugged topography and of the anisotropic reflection of snow and
ice are particularly investigated. The methods are tested on the
Saint Sorlin Glacier (Grandes Rousses area, French Alps). The
accuracy of the retrieved albedo is estimated using both field
measurements, at two automatic weather stations located on the
glacier, and albedo values derived from terrestrial photographs. For
summers 2008 and 2009, the root mean square deviation (RMSD) between
field measurements and the broadband albedo retrieved from MODIS
data at 250 m spatial resolution was found to be 0.052 or
about 10% relative error. The RMSD estimated for the MOD10
daily albedo product is about three times higher. One decade
(2000–2009) of MODIS data were then processed to create a time
series of albedo maps of Saint Sorlin Glacier during the ablation
season. The annual mass balance of Saint Sorlin Glacier was
compared with the minimum albedo value (average over the whole
glacier surface) observed with MODIS during the ablation
season. A strong linear correlation exists between the two
variables. Furthermore, the date when the average albedo of the
whole glacier reaches a minimum closely corresponds to the period
when the snow line is located at its highest elevation, thus when the
snow line is a good indicator of the glacier equilibrium line. This
indicates that this strong correlation results from the fact that
the minimal average albedo values of the glacier contains
considerable information regarding the relative share of areal
surfaces between the ablation zone (i.e. ice with generally low
albedo values) and the accumulation zone (i.e. snow with
a relatively high albedo). As a consequence, the monitoring of the
glacier surface albedo using MODIS data can provide a useful means
to evaluate the interannual variability of the glacier mass
balance. Finally, the albedo in the ablation area of Saint Sorlin
Glacier does not exhibit any decreasing trend over the study period,
contrasting with the results obtained on Morteratsch Glacier in the
Swiss Alps. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|