Assessment of interannual variations in the surface mass balance of 18 Svalbard glaciers from the Moderate Resolution Imaging Spectroradiometer/Terra albedo product

摘要

We estimate annual anomalies of the surface mass balance of glaciers on Svalbard for the period 2000–2005 (six years), by calculating the so-called “satellite-derived mass balance” (B sat ) from time series of satellite-derived surface albedos. The method needs no other input variables. Surface albedos are extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS)/Terra albedo product. We validate the MODIS albedos by comparing them with in situ measurements on Kongsvegen, and we find a low root-mean-square error of 0.04 for higher-quality MODIS data. Confidence in the MODIS product is also provided by realistic profiles of albedo along glacier centerlines. We apply the method to 18 glaciers that are evenly distributed over the archipelago. Correlation coefficients of time series of B sat and direct measurements of the annual mass balance on Kongsvegen and Hansbreen are highly significant (0.94 and 0.82, respectively). Moreover, spatial distributions of the anomalies for individual years are coherent. Disadvantages of the method are that absolute values of the mass balance cannot be determined and that the interannual variability is underestimated. The latter might be corrected by equations to be established with mass balance models.