Abstract
Abstract. The mass balance of glaciers and ice caps is sensitive to changing climate conditions. The mass changes derived in this study are determined from elevation changes derived measured by the Ice, Cloud, and land Elevation Satellite (ICESat) for the time period 2003–2009. Four methods, based on interpolation and extrapolation, are used to regionalize these elevation changes to areas without satellite coverage. A constant density assumption is then applied to estimate the mass change by integrating over the entire glaciated region. The main purpose of this study is to investigate the sensitivity of the regional mass balance of Arctic ice caps and glaciers to different regionalization schemes. The sensitivity analysis is based on studying the spread of mass changes and their associated errors, and the suitability of the different regionalization techniques is assessed through cross-validation. The cross-validation results shows comparable accuracies for all regionalization methods, but the inferred mass change in individual regions, such as Svalbard and Iceland, can vary up to 4 Gt a−1, which exceeds the estimated errors by roughly 50% for these regions. This study further finds that this spread in mass balance is connected to the magnitude of the elevation change variability. This indicates that care should be taken when choosing a regionalization method, especially for areas which exhibit large variability in elevation change.
Highlights
The most recent assessments from the Intergovernmental Panel on Climate Change (Vaughan et al, 2014) and theSnow, Water, Ice and Permafrost in the Arctic Assessment (AMAP, 2012) state that the mass loss from glaciers and ice sheets is a major contributor to sea-level rise
We focus on five regions in the Arctic: Iceland (ICEL), Svalbard (SVLB), the Russian High Arctic (RUS), Canadian Arctic North (CAN) and Canadian Arctic South (CAS)
The along-track rates of elevation change have been derived for the five regions: ICEL, SVLB, CAS, CAN and RUS
Summary
The most recent assessments from the Intergovernmental Panel on Climate Change (Vaughan et al, 2014) and theSnow, Water, Ice and Permafrost in the Arctic Assessment (AMAP, 2012) state that the mass loss from glaciers and ice sheets is a major contributor to sea-level rise. The use of satellite altimetry to determine the elevation change in the major ice sheets has been possible since the late 1980s and was pioneered by Zwally et al (1987), Wingham et al (1998) and others In recent years this has been expanded to ice caps and glaciers using both satellite and airborne altimetry, in studies such as Gardner et al (2011), Moholdt et al (2010a, 2012), Abdalati et al (2004) and Arendt et al (2002, 2006). Determining the regional rate of change in the entire glaciated area involves interpolation or extrapolation (referred to hereinafter as regionalization) of the elevation changes to unmeasured areas away from the satellite ground tracks This regionalization might introduce a large uncertainty to the volume estimate, as the track coverage over individual ice caps and glaciers are usually limited
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