Canadian High Arctic glacier surface mass budget (1950-2009)
Abstract
The Canadian High Arctic (> 74 °N) contains the largest volume of land ice on Earth outside of the ice sheets, accounting for ~22% of the volume of all glaciers, ice caps, and ice fields. Despite the region’s relatively high density of long-term (50+ years) surface mass balance records, the only published measurement based estimate of regional mass change was produced using airborne laser altimetry surveys of the region’s major ice masses. From these surveys it was estimated that between 1995 and 2000 the Canadian High Arctic was losing land ice at a rate of 12 Gt3 a-1. Since that time the Canadian High Arctic has experienced some of the warmest summer temperatures and most negative glacier mass balances on record. To estimate recent changes in the region’s surface mass balance and to place these changes in a longer-term context we simulate the surface mass balance for the period 1950 to 2009 using a temperature-index model that is forced with downscaled NCEP/NCAR climate reanalysis temperatures and precipitation. Prior to downscaling, the reanalysis field were corrected for biases using an extensive observational dataset that was compiled specifically for this study. The model is run at a horizontal resolution of 0.5 km by 0.5 km in order to resolve the observed steep spatial gradients in melt and was calibrated using over 3500 point measurements of surface mass balance spanning a period greater than 50 years. Uncertainties are assessed using the Monte Carlo method. Model results show a period of increased surface mass loss between 1956 and 1962 and a recent acceleration in loss rates since 2007. Modeled surface loss rates for the period 2003-2009 are an order of magnitude larger than the 1963-2003 average and, when combined with an estimate of the mass loss rate by iceberg calving, are generally consistent with independent estimates from IceSat laser altimetry and GRACE satellite gravimetry.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.C34A..06G
- Keywords:
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- 0720 CRYOSPHERE / Glaciers;
- 0762 CRYOSPHERE / Mass balance;
- 0798 CRYOSPHERE / Modeling