Climate Dynamics

, Volume 39, Issue 5, pp 1093–1105

Impact of ice sheet induced North Atlantic oscillation on East Asian summer monsoon during an interglacial 500,000 years ago

Article

DOI: 10.1007/s00382-011-1213-z

Cite this article as:
Sundaram, S., Yin, Q.Z., Berger, A. et al. Clim Dyn (2012) 39: 1093. doi:10.1007/s00382-011-1213-z

Abstract

Marine Isotope Stage (MIS) 13, an interglacial about 500,000 years ago, is unique due to an exceptionally strong East Asia summer monsoon (EASM) occurring in a relatively cool climate with low greenhouse gas concentrations (GHG). This paper attempts to find one of the possible mechanisms for this seeming paradox. Simulations with an Earth System model LOVECLIM show that the presence of ice sheets over North America and Eurasia during MIS-13 induces a positive phase of the winter North Atlantic Oscillation (NAO) like feature. The ocean having a longer memory than the atmosphere, the oceanic anomalies associated with NAO persists until summer. The signals of summer NAO are transmitted to East Asia to reinforce the monsoon there through the stationary waves excited at the Asian Jet entrance. The geopotential height shows clearly a mid-latitude wave train with positive anomalies over the eastern Mediterranean/Caspian Sea and the Okhotsk Sea and a negative anomaly over Lake Baikal. This reinforces the effect of the high-latitude wave train induced independently by the Eurasian ice sheet topography as shown in previous study. These features reinforce the Meiyu front and enhance the precipitation over East Asia. The results obtained from LOVECLIM are further confirmed by an atmospheric general circulation model, ARPEGE.

Keywords

North Atlantic OscillationEast Asian summer monsoonBlocking highsInterglacial MIS-13Ice sheets

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  1. 1.Earth and Life Institute (ELI), Georges Lemaitre Centre for Earth and Climate Research (TECLIM)Université Catholique de LouvainLouvain la NeuveBelgium