Sensitivity of geodetic glacier mass balance estimation to DEM void interpolation [post]

Robert McNabb, Christopher Nuth, Andreas Kääb, Luc Girod
2018 unpublished
<p><strong>Abstract.</strong> Glacier mass balance is a direct expression of climate change, with implications for sea level, ocean chemistry, oceanic and terrestrial ecosystems, and water resources. Traditionally, glacier mass balance has been estimated using in-situ measurements of changes in surface height and density at select locations on the glacier surface, or by comparing changes in surface height using repeat, full-coverage digital elevation models (DEMs), also called
more » ... (DEMs), also called the geodetic method. DEMs often have gaps in coverage (<q>voids</q>) based on the nature of the sensor used and the surface being measured. The way that these voids are accounted for has a direct impact on the estimate of geodetic glacier mass balance, though a systematic comparison of different proposed methods has been heretofore lacking. In this study, we determine the impact and sensitivity of void-filling methods on estimates of volume change. Using two spatially complete, high-resolution DEMs over Southeast Alaska, USA, we compare 11 different void-filling methods on a glacier-by-glacier and regional basis. We find that a few methods introduce biases of up to 20 % in the regional results, while other methods give results very close (< 1 % difference) to the true, non-voided volume change estimates. Finally, we independently show using ASTER DEMs that some of best-performing methods are more robust than others, depending on the properties of the original DEMs, and therefore recommend that studies compare a few of these methods to estimate the uncertainty introduced by filling DEM voids.</p>
doi:10.5194/tc-2018-175 fatcat:dv4uw7ic7fbzhcq6tkhtipudg4