Observations of enhanced thinning in the upper reaches of Svalbard glaciers
Changes in the volume and extent of land iceof the Svalbard archipelago have been the subject of considerableresearch since their sensitivity to changes in climatewas first noted. However, the measurement of thesechanges is often necessarily based on point or profile measurementswhich may not be rep...
| Published in: | The Cryosphere |
|---|---|
| Main Authors: | , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Copernicus GmbH
2012
|
| Subjects: | |
| Online Access: | https://doi.org/10.5194/tc-6-1369-2012 http://ecite.utas.edu.au/89652 |
| Summary: | Changes in the volume and extent of land iceof the Svalbard archipelago have been the subject of considerableresearch since their sensitivity to changes in climatewas first noted. However, the measurement of thesechanges is often necessarily based on point or profile measurementswhich may not be representative if extrapolatedto a whole catchment or region. Combining high-resolutionelevation data from contemporary laser-altimetry surveysand archived aerial photography makes it possible to measurehistorical changes across a glaciers surface without theneed for extrapolation. Here we present a high spatial resolutiontime-series for six Arctic glaciers in the Svalbardarchipelago spanning 1961 to 2005. We find high variabilityin thinning rates between sites with prevalent elevationchanges at all sites averaging −0.59 0.04ma −1 between19612005. Prior to 1990, ice surface elevation was changingat an average rate of −0.52 0.09ma −1 which decreased to−0.76 0.10ma −1 after 1990. Setting the elevation changesagainst the glaciers altitude distribution reveals that significantincreases in thinning rates are occurring most notablyin the glaciers upper reaches. We find that these changesare coincident with a decrease in winter precipitation at theLongyearbyen meteorological station and could reflect a decreasein albedo or dynamic response to lower accumulation.Further work is required to understand fully the causes ofthis increase in thinning rates in the glaciers upper reaches.If on-going and occurring elsewhere in the archipelago, thesechanges will have a significant effect on the regions futuremass balance. Our results highlight the importance of understandingthe climatological context of geodetic mass balancemeasurements and demonstrate the difficulty of using indexglaciers to represent regional changes in areas of strong climatologicalgradients. |
|---|