scholarly journals Importance of the advection scheme for the simulation of water isotopes over Antarctica by general circulation models: a case study with LMDZ-iso (LMDZ5a revision 1750)

2017 ◽  
Author(s):  
Alexandre Cauquoin ◽  
Camille Risi
Keyword(s):  
General Circulation ◽  
General Circulation Models ◽  
Temperature Relationship ◽  
Water Isotopes ◽  
Good Representation ◽  
Advection Scheme ◽  
Atmospheric General Circulation ◽  
Atmospheric General Circulation Models ◽  
Polar Water

Abstract. Atmospheric general circulation models (AGCMs) are known to have a warm and isotopically enriched bias over Antarctica. We test here the hypothesis that these biases are consequences of a too diffusive advection. Using the LMDZ-iso model, we show that a good representation of the advection, especially on the horizontal, is very important to reduce the bias in the isotopic contents of precipitation above this area and to improve the modelled water isotopes – temperature relationship. A good advection scheme is thus essential when using GCMs for paleoclimate applications based on polar water isotopes.

scholarly journals A Review of Water Isotopes in Atmospheric General Circulation Models: Recent Advances and Future Prospects

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Xi Xi
Keyword(s):  
Model Validation ◽  
General Circulation ◽  
Hydrological Cycle ◽  
General Circulation Models ◽  
Water Isotopes ◽  
Future Prospects ◽  
Surface Evaporation ◽  
Atmospheric General Circulation ◽  
Atmospheric General Circulation Models ◽  
Water Isotopologues

Stable water isotopologues, mainly 1H2O, 1H2HO (HDO), and H12O18, are useful tracers for processes in the global hydrological cycle. The incorporation of water isotopes into Atmospheric General Circulation Models (AGCMs) since 1984 has helped scientists gain substantial new insights into our present and past climate. In recent years, there have been several significant advances in water isotopes modeling in AGCMs. This paper reviews and synthesizes key advances accomplished in modeling (1) surface evaporation, (2) condensation, (3) supersaturation, (4) postcondensation processes, (5) vertical distribution of water isotopes, and (6) spatial δ18O-temperature slope and utilizing (1) spectral nudging technique, (2) higher model resolutions, and (3) coupled atmosphere-ocean models. It also reviews model validation through comparisons of model outputs and ground-based and spaceborne measurements. In the end, it identifies knowledge gaps and discusses future prospects of modeling and model validation.

The Last Interglaciation in Northeast Siberia

1995 ◽  
Vol 43 (2) ◽  
pp. 147-158 ◽  
Author(s):  
Anatoly V. Lozhkin ◽  
Patricia M. Anderson
Keyword(s):  
General Circulation ◽  
General Circulation Models ◽  
The Arctic ◽  
The North ◽  
River Terraces ◽  
Atmospheric General Circulation ◽  
Winter Temperatures ◽  
Atmospheric General Circulation Models ◽  
Arctic Coast ◽  
Organic Deposits

AbstractAlluvial, fluvial, and organic deposits of the last interglaciation are exposed along numerous river terraces in northeast Siberia. Although chronological control is often poor, the paleobotanical data suggest range extensions of up to 1000 km for the primary tree species. These data also indicate that boreal communities of the last interglaciation were similar to modern ones in composition, but their distributions were displaced significantly to the north-northwest. Inferences about climate of this period suggest that mean July temperatures were warmer by 4 to 8°C, and seasonal precipitation was slightly greater. Mean January temperatures may have been severely cooler than today (up to 12°C) along the Arctic coast, but similar or slightly warmer than present in other areas. The direction and magnitude of change in July temperatures agree with Atmospheric General Circulation Models, but the 126,000-year-B.P. model results also suggest trends opposite to the paleobotanical data, with simulated cooler winter temperatures and drier conditions than present during the climatic optimum.

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