Results of a climate model for Triassic Pangaea
We have used a new General Circulation Model, GENESIS Version 1.02, derived from the U. S. National Center for Atmospheric Research Community Climate Model I (NCAR-CCM I) to simulate the climate of an Earth with realistic Pangaean geography. The climate model was run assuming that the ocean heat flu...
| Main Authors: | , , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Schweizerbart
1994
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| Subjects: | |
| Online Access: | https://oceanrep.geomar.de/id/eprint/35691/ https://oceanrep.geomar.de/id/eprint/35691/1/20170116125334.pdf |
| Summary: | We have used a new General Circulation Model, GENESIS Version 1.02, derived from the U. S. National Center for Atmospheric Research Community Climate Model I (NCAR-CCM I) to simulate the climate of an Earth with realistic Pangaean geography. The climate model was run assuming that the ocean heat flux was similar to that of today, atmospheric C02 content was four times that of today, the solar constant was 2 % less than today, and the Earth's orbit was circular, with mean obliquity 23.4°. Models were run for paleogeographies at 245 Ma (Scythian) and 225 Ma (Carnian). The results indicate that no ice cap would develop over the land, and there is no permanent sea ice. The seasonal temperature Variation in the interior of the continent is in the order of 50 °C. The Continental areas are very dry except for a few Coastal areas and along uplifts. The models both suggest an extreme seasonal monsoonal circulation, with strong westerly winds parallel to the entire coast of Gondwana and the east coast of Laurasia during the northern hemisphere summet. In both hemispheres, the effect is to cause coastal upwelling. The model also predicts permafrost in the deeper soil layers poleward of 50° N and S. The effects of topographic uplifts on the atmospheric circulation are pervasive. Topography strongly affects the monsoonal circulation causing major deviations of the wind Systems suggested in model runs with idealized geographies. Topography also plays a crucial role in concentrating rainfall in a few small areas. It is evident that in order to have a realistic Simulation of paleoclimate, an accurate representation of the paleotopography is essential. It is also evident that the paleoclimate models may be useful in suggesting geological criteria that can confirm or reject the predicted paleoclimatic conditions. |
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