Articles | Volume 11, issue 2
Clim. Past, 11, 305–326, 2015

Special issue: Integrated analysis of interglacial climate dynamics

Clim. Past, 11, 305–326, 2015

Research article 19 Feb 2015

Research article | 19 Feb 2015

The evolution of sub-monsoon systems in the Afro-Asian monsoon region during the Holocene– comparison of different transient climate model simulations

A. Dallmeyer1, M. Claussen1,2, N. Fischer1, K. Haberkorn2, S. Wagner3, M. Pfeiffer4, L. Jin5, V. Khon6,7, Y. Wang8, and U. Herzschuh8,9 A. Dallmeyer et al.
  • 1Max Planck Institute for Meteorology, Bundesstrasse 53, 20146 Hamburg, Germany
  • 2Meteorological Institute, Centrum für Erdsystemforschung und Nachhaltigkeit (CEN), Universität Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany
  • 3Helmholtz Center Geesthacht, Institute for Coastal Research, 21502 Geesthacht, Germany
  • 4Alfred Wegener Institute for Polar and Marine Research, 27568 Bremerhaven, Germany
  • 5Key Laboratory of Western China's Environmental Systems, Lanzhou University, Research School of Arid Environment and Climate Change, Lanzhou 730000, China
  • 6Institute of Geosciences, Christian-Albrechts Universität zu Kiel, Ludewig-Meyn-Str. 10-14, 24118 Kiel, Germany
  • 7A. M. Obukhov Institute of Atmospheric Physics RAS, Pyzhevsky 3, 117019 Moscow, Russia
  • 8Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, 14473 Potsdam, Germany
  • 9Institute of Earth and Environmental Science, University of Potsdam, Karl-Liebknecht-Strasse 24–25, 14476 Potsdam, Germany

Abstract. The recently proposed global monsoon hypothesis interprets monsoon systems as part of one global-scale atmospheric overturning circulation, implying a connection between the regional monsoon systems and an in-phase behaviour of all northern hemispheric monsoons on annual timescales (Trenberth et al., 2000). Whether this concept can be applied to past climates and variability on longer timescales is still under debate, because the monsoon systems exhibit different regional characteristics such as different seasonality (i.e. onset, peak and withdrawal). To investigate the interconnection of different monsoon systems during the pre-industrial Holocene, five transient global climate model simulations have been analysed with respect to the rainfall trend and variability in different sub-domains of the Afro-Asian monsoon region. Our analysis suggests that on millennial timescales with varying orbital forcing, the monsoons do not behave as a tightly connected global system. According to the models, the Indian and North African monsoons are coupled, showing similar rainfall trend and moderate correlation in centennial rainfall variability in all models. The East Asian monsoon changes independently during the Holocene. The dissimilarities in the seasonality of the monsoon sub-systems lead to a stronger response of the North African and Indian monsoon systems to the Holocene insolation forcing than of the East Asian monsoon and affect the seasonal distribution of Holocene rainfall variations. Within the Indian and North African monsoon domain, precipitation solely changes during the summer months, showing a decreasing Holocene precipitation trend. In the East Asian monsoon region, the precipitation signal is determined by an increasing precipitation trend during spring and a decreasing precipitation change during summer, partly balancing each other. A synthesis of reconstructions and the model results do not reveal an impact of the different seasonality on the timing of the Holocene rainfall optimum in the different sub-monsoon systems. Rather they indicate locally inhomogeneous rainfall changes and show that single palaeo-records should not be used to characterise the rainfall change and monsoon evolution for entire monsoon sub-systems.