Estimation of mass balance of Dongkemadi glaciers with multiple methods based on multi-mission satellite data

Abstract

In the context of climate change and variability, the change of glaciers over Qinghai-Tibet Plateau (QTP) has substantial impact on regional water resource and supply in a large geographical area in Asia. In this study, the recent change of glaciers in the Dongkemadi region in the central QTP was estimated by using multi-date Landsat images acquired over 2000–2011 and altimetry data derived from ICESat over 2003–2008. The biased elevation sampling of ICESat footprints in different laser periods was corrected before trend fitting of elevation changes by estimating the gradients of elevation changes. The results show that glaciers experienced notable recession in the last decade, at a linear shrinking rate of 0.21 km2 (0.26%) y−1 in area and a thinning rate of 0.56 m y−1. Mass balances based on ICESat (−421.2 ± 83 mm y−1 w.e) and area-volume scaling method (−487.2 ± 96 mm y−1) agree well with the in-situ measurements of Xiao Dongkemadi (−444.6 mmy−1 w.e.), giving uncertainties with density assumptions. The results were compared with other studies, and indicate accelerated recession which may be linked with a significant warming trend in recent decades over the QTP. This study demonstrates consistent glacier changes respectively derived from different time-series data, and the potential of consensus estimates by combining multi-mission satellite data.