Investigation of rapid climate changes and their consequences for the Asian Monsoon during the younger climate history
CAHOL aims to reconstruct rapid climate changes, so called tipping points, and their consequences for the central Asian climate as well as the interaction between the monsoon and the westerly wind systems. A tipping point marks a threshold where the climate transitions from a stable state into another stable state takes place. As a consequence, climate regions may shift while the frequency and consequences of extreme events may change. The interaction of the westerly wind system and the Asian monsoon affects the climate of central Asia on seasonal and decadal as well as on orbital time scales. The understanding of the interplay of both climatic systems is still insufficient but can be improved with the help of high-resolution climate archives. The focus of CAHOL is, therefore, the transition phase between the Holocene climate optimum and the late Holocene as well as phases of strong cooling and aridity for the entire Holocene, which are probably connected to multi-decadal climate changes in the North Atlantic sector, for instance due to the AMO (Atlantic Multidecadal Oscillation) or NAO (North Atlantic Oscillation).
To reconstruct these tipping points, sediment archives from the lake Chatyr Kol (Kyrgyzstan, westerly wind system), the northeast Arabian Sea (transitions zone westerly wind system and Indian Monsoon) as well as the South China Sea (East Asian Monsoon) will be investigated using biogeochemical, micro-palaeontological and terrestrial-geochemical proxies. These reconstructions should provide the basis for climate simulations of those tipping points. Overall, the project’s outcome should help to estimate regional climate impacts and hazards evolving in a changing climate.
The Institute for Geology of the University of Hamburg is part of the sub-project “WP2: Arabian Sea” and aims at the reconstruction of the variability of the Indian Monsoon and its interactions with the westerly wind system. Therefore, a marine sediment core from the Arabian Sea (offshore Pakistan), which comprises the whole Holocene, will be investigated using biogeochemical and terrestrial geochemical methods. The focus is to reconstruct the sea surface temperature (alkenones), the primary productivity (organic carbon, carbonate/opal, d15N) as well as to quantify the terrigenous input (grain size, d13Ccarb).
Project partner WP1 (Chatyr Kol, SE Kyrgyzstan):
- German Research Centre for Geoscience (GFZ), Potsdam (Prof. Dr. Achim Brauer, Dr. Jens Mingram)
- Max Planck Institute for Biogeochemistry (MPI), Jena (Prof. Dr. Gerd Gleixner)
- Institute for Geosystems and Bioindication, TU Braunschweig (Prof. Dr. Antje Schwalb)
- Institute for Meteorology, FU Berlin (Prof. Dr. Ulrich Cubasch, Dr. Bijan Fallah)
Project partner WP2 (Arabian Sea):
- Institute for Geology, University of Hamburg (Dr. Nicole Burdanowitz , Dr. Birgit Gaye)
- Leibniz Center for Tropical Marine Ecology (ZMT), Bremen (Dr. Tim Rixen)
- Department of Geosciences (FBG), University of Tübingen (Dr. Hartmut Schulz)
- Institute for Geosciences (IfG), University of Kiel (Dr. Joachim Segschneider)
Project partner WP3 (South China Sea):
- Center for Marine Environmental Sciences (MARUM), Bremen (Prof. Dr. Michael Schulz, Dr. Mahyar Mohtadi)
Duration of the project: 2016-2019
Information about the project at the IfG: Dr. Nicole Burdanowitz , Dr. Birgit Gaye