Articles | Volume 4, issue 2
Clim. Past, 4, 79–90, 2008
https://doi.org/10.5194/cp-4-79-2008

Special issue: The East Asian Monsoon: past, present and future

Clim. Past, 4, 79–90, 2008
https://doi.org/10.5194/cp-4-79-2008

  23 May 2008

23 May 2008

The Eurasian ice sheet reinforces the East Asian summer monsoon during the interglacial 500 000 years ago

Qiuzhen Yin, A. Berger, E. Driesschaert, H. Goosse, M. F. Loutre, and M. Crucifix Qiuzhen Yin et al.
  • Catholic University of Louvain, Institute of Astronomy and Geophysics G., Lemaître, Chemin du Cyclotron 2, 1348 Louvain-la-Neuve, Belgium

Abstract. Deep-sea and ice-core records show that interglacial periods were overall less "warm" before about 420 000 years ago than after, with relatively higher ice volume and lower greenhouse gases concentration. This is particularly the case for the interglacial Marine Isotope Stage 13 which occurred about 500 000 years ago. However, by contrast, the loess and other proxy records from China suggest an exceptionally active East Asian summer monsoon during this interglacial. A three-dimension Earth system Model of Intermediate complexity was used to understand this seeming paradox. The astronomical forcing and the remnant ice sheets present in Eurasia and North America were taken into account in a series of sensitivity experiments. Expectedly, the seasonal contrast is larger and the East Asian summer monsoon is reinforced compared to Pre-Industrial time when Northern Hemisphere summer is at perihelion. Surprisingly, the presence of the Eurasian ice sheet was found to reinforce monsoon, too, through a south-eastwards perturbation planetary wave. The trajectory of this wave is influenced by the Tibetan plateau.