Linking glacier annual mass balance and glacier albedo retrieved from MODIS data

Abstract

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 snowline is located at its highest elevation, thus when the snowline 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 a 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 inter-annual 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

Annual Glacier-Wide Mass Balance (2000–2016) of the Interior Tibetan Plateau Reconstructed from MODIS Albedo Products

“…Recently, some researchers have proposed that this albedo-based method may be extrapolated to other neighboring glaciers under similar climate conditions [21][22][23] based on the robust relationship between MODIS-derived albedo and annual mass balance. In this study, the good agreement between mass balance estimates derived from the albedo-based method and the geodetic Conversely, the magnitude of glacier mass loss (increase) in the GLDD is slightly bigger (smaller) than the PIC, although the glacier-covered area in the GLDD is about two and a half times bigger.…”

“…Hence, we used 10% of the annual maximum MO&YD10A1 values as the MO&YD10A1 albedo errors according to these previous studies. Using the method proposed in [22,23],…”

“…Among these glacier properties, recent studies have revealed that the variation of glacier-wide surface albedo has shown outstanding potentials in obtaining annual or seasonal mass balance, because minimum surface albedo was directly related to AAR and ELA. Dumont et al [22] concluded that a strong linear correlation exits between minimum Moderate Resolution Imaging Spectroradiometer (MODIS)-derived albedo value and glacier mass balance, which could be used to retrieve inter-annual variations of glacier mass balance. Sirguey et al [23] confirmed that minimum glacier-wide albedo was a reliable predictor for annual mass variability in a maritime glacier and reconstructed both winter and summer balance records.…”

“…In recent years, remote sensing techniques have proven to be useful for glacier monitoring, since the available satellite sensors are increasing and their spatial, radiometric and temporal resolutions are improved [11,12].Glacier mass fluctuations can be calculated by using several parameters derived from remote sensing images, e.g., the difference between two digital elevation models (DEMs) at different times [13][14][15][16], the equilibrium-line altitude (ELA) at the end of the hydrological year [12,17,18], the accumulation-area ratio (AAR) [19,20] over a glacier, and the average glacier surface albedo [21][22][23][24]. Among these glacier properties, recent studies have revealed that the variation of glacier-wide surface albedo has shown outstanding potentials in obtaining annual or seasonal mass balance, because minimum surface albedo was directly related to AAR and ELA.…”

Cross-Comparison of Albedo Products for Glacier Surfaces Derived from Airborne and Satellite (Sentinel-2 and Landsat 8) Optical Data

“…Several studies have used Landsat or MODIS data to derive glacier surface albedo distribution [20][21][22] and compared their results with local automated weather stations [23] or linked them to glacier mass balance estimates [2,24]. In particular, the 500 m MODIS albedo product was used in several studies [2][3][4]25].…”