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- Title
Atmospheric moisture supersaturation in the near-surface atmosphere at Dome C, antarctic plateau.
- Authors
Genthon, Christophe; Piard, Luc; Vignon, Etienne; Madeleine, Jean-Baptiste; Casado, Mathieu; Gallée, Hubert
- Abstract
Supersaturations in the natural atmosphere are frequent at the top of the troposphere where cirrus clouds form, but are very infrequent near the surface where the air is generally warmer and laden with liquid and/or ice condensation nuclei. An exception is the surface of the high antarctic plateau. One year of atmospheric moisture measurement at the surface of Dome C on the East Antarctic plateau is presented and compared with results from 2 models implementing cold microphysics parametrizations: the European Center for Medium-range Weather Forecasts through its operational analyzes, and the Model Atmosphérique Régional. The measurements are obtained using commercial hygrometry sensors modified to allow air sampling without affecting the moisturecontent even in case of supersaturation. Supersaturations are very frequent in the observations and in the models, but the statistical distribution differs both between models and observations and between the 2 models, living much room for improvements in both models. Unadapted hygrometry sensors generally fail to report supersaturations, and most reports of atmospheric moisture on the antarctic plateau are thus likely biased low. This is unlikely to strongly affect estimations of surface sublimation because supersaturations are more frequent as temperature is lower, and moisture quantities and thus water fluxes are very small anyway. Ignoring supersaturation may be a more serious issue when considering water isotopes, a tracer of phase change and temperature, largely used to interpret snow and ice samples from the antarctic plateau and reconstruct past climates and environments from ice cores. Longer and more continuous in situ observation series to test parameterizations of cold microphysics, such as those used in the formation of cirrus clouds in climate models, can be obtained at surface levels than higher in the atmosphere.
- Subjects
EAST Antarctica (Antarctica); WEATHER forecasting; TROPOSPHERE; SUPERSATURATION; CIRRUS clouds
- Publication
Atmospheric Chemistry & Physics Discussions, 2016, p1
- ISSN
1680-7367
- Publication type
Article
- DOI
10.5194/acp-2016-670