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- Title
The Isotopic Composition of Present-Day Antarctic Snow in a Lagrangian Atmospheric Simulation.
- Authors
Helsen, M. M.; Van de Wal, R. S. W.; Van den Broeke, M. R.
- Abstract
The isotopic composition of present-day Antarctic snow is simulated for the period September 1980–August 2002 using a Rayleigh-type isotope distillation model in combination with backward trajectory calculations with 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) data as meteorological input. Observed spatial isotopic gradients are correctly reproduced, especially in West Antarctica and in the coastal areas. However, isotopic depletion of snow on the East Antarctic plateau is underestimated, a problem that is also observed in general circulation models equipped with isotope tracers. The spatial isotope–temperature relation varies strongly, which indicates that this widely used relation is not applicable to all sites and temporal scales. Spatial differences in the seasonal amplitude are identified, with maximum values in the Antarctic interior and hardly any seasonal isotope signature in Marie Byrd Land, West Antarctica. The modeled signature of deuterium excess remains largely preserved during the last phase of transport, though the simulated relation of deuterium excess with δ18O suggests that parameterizations of kinetic isotopic fractionation can be improved.
- Subjects
ANTARCTICA; SNOW; ATMOSPHERE; WEATHER forecasting; METEOROLOGY; DEUTERIUM; WEATHER; ATMOSPHERIC circulation; SIMULATION methods &; models
- Publication
Journal of Climate, 2007, Vol 20, Issue 4, p739
- ISSN
0894-8755
- Publication type
Article
- DOI
10.1175/JCLI4027.1