Orbital Asian summer monsoon dynamics revealed using an isotope-enabled global climate model

Thibaut Caley (1) , Didier M. Roche (2, 3, 1) , Hans Renssen (1)

1 VU - Vrije Universiteit Amsterdam [Amsterdam]
2 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
3 CLIM - Modélisation du climat

The Asian summer monsoon dynamics at the orbital scale are a subject of considerable debate. The validity of Asian speleothem delta O-18 records as a proxy for summer monsoon intensity is questioned together with the ultimate forcing and timing of the monsoon. Here, using the results of a 150,000-year transient simulation including water isotopes, we demonstrate that Asian speleothem d18O records are not a valid proxy for summer monsoon intensity only at the orbital timescale. Rather, our results show that these records reflect annual variations in hydrologic processes and circulation regime over a large part of the Indo-Asian region. Our results support the role of internal forcing, such as sea surface temperature in the equatorial Pacific, to modulate the timing of monsoon precipitation recorded in paleo-proxies inside the Asian region.

Domaines: Sciences de la Terre

Thibaut Caley, Didier M. Roche, Hans Renssen. Orbital Asian summer monsoon dynamics revealed using an isotope-enabled global climate model. Nature Communications, 2014, 5, pp.5371. ⟨10.1038/ncomms6371⟩. ⟨cea-01103627⟩