Impact of Tectonic and Orbital Forcing on African Climate in a Regional Model
Abstract
The development of the East African Rift System (EARS) during the last 20 million years caused by tectonic forcing is supposed to influence the regional climate in Africa. However, also changes in the Earth’s orbital parameters have an influence on climate on these timescales. To analyse the influence of both tectonic and orbital forcing the non-hydrostatic regional climate model CLM is applied. The regional simulations are driven by different global simulations performed with the coupled ocean-atmosphere general circulation model ECHO-G. To analyse the impact of tectonic forcing different topographies representing different stages of the development of the EARS are applied in the models. The results indicate that the tectonic forcing has a strong impact on climate in Africa caused by changes in the circulation. To analyse the impact of orbital forcing orbital parameters leading to a strong change in insolation are chosen. One example is the last interglacial at 125000 years before present when the seasonality of insolation on the northern (southern) hemisphere is strongly enhanced (weakened) compared to preindustrial or present-day conditions. The simulation of this timeslice shows a strong impact of orbital forcing on climate in large parts of Africa caused by altered moisture transport.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFM.A33A0203P
- Keywords:
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- 1637 GLOBAL CHANGE / Regional climate change;
- 3355 ATMOSPHERIC PROCESSES / Regional modeling