www.clim-past-discuss.net/4/459/2008/ doi:10.5194/cpd-4-459-2008 © Author(s) 2008. This work is distributed under the Creative Commons Attribution 3.0 License. Monsoon response to changes in Earth's orbital parameters: comparisons between simulations of the Eemian and of the Holocene 1Laboratoire des Sciences du Climat et de l'Environnement, Unité mixte CEA-CNRS-UVSQ, Orme des Merisiers, bât. 712, 91191 Gif-sur-Yvette Cedex, France 2School of Geographical Sciences, Univ. of Bristol, University Road – Bristol BS8 1SS, UK Abstract. Monsoon is the major manifestation of the seasonal cycle in the tropical regions, and there is a wide range of evidence from marine and terrestrial data that monsoon characteristics are affected by changes in the Earth's orbital parameters. We consider 3 periods in the Eemian and in the Holocene that present some analogy in the Earth's orbital configuration in terms of obliquity and precession. Simulations with the IPSL_CM4 ocean-atmosphere coupled model allow us to discuss the response of the Indian and African monsoon in terms of amplitude and response to the insolation forcing. Results show that precession plays a large role in shaping the seasonal timing of the monsoon system. Differences are found in the response of the two sub-systems. They result from the phase relationship between the insolation forcing and the seasonal characteristics of each sub-system. Also the response of the Indian Ocean is very different in terms of temperature and salinity when the change in insolation occurs at the summer solstice or later in the year. Monsoon has a large contribution to heat and water transports. It is shown that the relative importance of monsoon on the change in the energetic of the tropical regions also vary with precession. Discussion Paper (PDF, 2733 KB) Interactive Discussion (Closed, 4 Comments) Final Revised Paper (CP) Special Issue Citation: Braconnot, P., Marzin, C., Grégoire, L., Mosquet, E., and Marti, O.: Monsoon response to changes in Earth's orbital parameters: comparisons between simulations of the Eemian and of the Holocene, Clim. Past Discuss., 4, 459-493, doi:10.5194/cpd-4-459-2008, 2008. Bibtex EndNote Reference Manager XML |