Orbital Asian summer monsoon dynamics revealed using an isotope-enabled global climate model.
The Asian summer monsoon dynamics at the orbital scale are a subject of considerable debate. The validity of Asian speleothem δ(18)O 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 δ(18)O 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.
Department of Earth Sciences, Earth and Climate Cluster, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands.
Thibaut
T
Caley
1] Department of Earth Sciences, Earth and Climate Cluster, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands [2] Laboratoire des Sciences du Climat et de l'Environnement (LSCE), CEA/CNRS-INSU/UVSQ, Gif-sur-Yvette F-91191, France.
Didier M
DM
Roche
Department of Earth Sciences, Earth and Climate Cluster, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, The Netherlands.
Hans
H
Renssen