Extreme accumulation on Patagonian ice fields revealed by high-resolution regional climate modeling
Abstract
Gravimetric observations and differential DEM's indicate that the Patagonian ice fields are currently thinning and retreating. Little is known, however, on the mechanisms that drive this ice mass loss. In particular, surface mass balance (SMB) of the ice fields is poorly constrained, because the wet southern Andes climate complicates performing in-situ measurements. Instead, regional climate modeling may provide the first, independent estimate of the ice field's SMB. Here we present results from a high-resolution (5.5 km) regional atmospheric climate and multi-layer snow model (RACMO2), forced by ERA-Interim atmospheric and ocean surface fields (1979-2013). The model is evaluated using existing weather stations, precipitation gauges, and available glacier firn cores. Our results confirm the occurrence of extremely high accumulation on the higher portions of both ice fields (10-35 m w.e. of snow per year). Precipitation is abundant throughout the entire year, and driven by quasi-continuous atmospheric westerlies, in combination with significant orographic forcing. On the other hand, we find strong ablation on the outlet glacier tongues, although these are only partly resolved by the model grid. Integrated over the ice fields, we find no significant recent trend in the SMB.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.C21B0630L
- Keywords:
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- 0720 CRYOSPHERE Glaciers;
- 0762 CRYOSPHERE Mass balance 0764 Energy balance;
- 3354 ATMOSPHERIC PROCESSES Precipitation;
- 3355 ATMOSPHERIC PROCESSES Regional modeling