Project OC3

Atmosphere-ocean interactions between the high and low latitudes control global climate variability and ultimately the Earth's transport of energy from warm equatorial regions to cold polar latitudes. Paleoclimate research and climate models demonstrate that biological and physical processes operating in polar regions play a key role in driving and amplifying global climate variability on timescales from decades to millennia. Ocean circulation changes in polar latitudes are transferred to the tropics both in the surface ocean and in intermediate water masses. On the other hand, tropical atmosphere-ocean variability such as changes in the El Niño-Southern Oscillation has a strong impact on Polar Regions and interacts with high-latitude interannual to decadal-scale climate modes (Liu et al. 2002).
It is proposed to derive atmosphere and ocean climate signals at millennial and up to decadal time scales focusing on the climate variability during the Holocene and its contrast to the last glacial. The Project will utilize high resolution sediment records from the polar North and South Pacific to be collected during five expeditions with RV POLARSTERN and RV SONNE scheduled for 2009-2011, augmented by ongoing work on ultra-high resolution records from the Chilean Fjords and adjacent continental margin as well as from the Scotia Sea which connects our Project to the Atlantic Southern Ocean. Further support comes from two Cluster of Excellence Projects now integrated in OC3, which provide information on dust records (ice and marine, A12) and tropical thermocline variability (A10). OC3 is strongly related to IPCC 2007 requirements as well as the international initiatives IPICS (40-kyr and 2-kyr networks) and PAGES-BIPOMAC. The proxy-data framework will be flanked by existing and new climate model baseline simulations focusing on different states of glacial climate (Last Glacial Maximum, millennial-scale variability during Marine Isotope Stage 3), and the Holocene. Proxy data from the Pacific realm may be put into global perspectives by our global model simulations with respect to both the spatial and temporal characteristics of teleconnections and in more detail by designing specific sensitivity experiments (e.g., partial coupling method).