Asynchronous climate change in Asia and Europe during the B/A YD transition
Ice cores from central Greenland are the temporally best resolved records of northern hemisphere climate of the last glacial period. Here we show that during the last glacial period (MIS 4 to MIS 2) East Asian Monsoon variations are directly recorded in the North-GRIP ice core. The East Asian Winter...
|Summary:||Ice cores from central Greenland are the temporally best resolved records of northern hemisphere climate of the last glacial period. Here we show that during the last glacial period (MIS 4 to MIS 2) East Asian Monsoon variations are directly recorded in the North-GRIP ice core. The East Asian Winter Monsoon strength as inferred from Chinese loess deposits correlates well with the concentration and size distribution of insoluble mineral particles in the North-GRIP core, and we infer that the ice core microparticle record can be taken as a proxy for East Asian Winter Monsoon strength. Further, reconstructions of the Asian summer monsoon strength, which controls the transport of moisture into the source regions, correlate well with the Ca/dust ratio at North-GRIP: e.g. the onset of at approx. 14.8 ka BP and the depression during MIS4, which have been inferred from East Asian loess-paleosol sequences, are also seen at NGRIP. These findings yield a new basis for ice core interpretation and put tighter constrains on the dating of Chinese loess-paleosol sequences. Finally, we take d18O as a proxy for North Atlantic region temperature and compare the timing of climatic changes in Europe and Asia at rapid climatic transitions during the last glacial period; this can be done with high temporal accuracy because all proxies are from the ice core and do not underlie relative dating uncertainties. We find that at rapid cold-to-warm transitions during the last glacial period Asian winter monsoon changes synchronously with North Atlantic region temperature, while Asian summer monsoon lags by approx. 45 years. We also find that the onset of the Younger Dryas event appears ~350 years earlier in the Asian summer monsoon than is commonly recognized for North Atlantic region temperature, which suggests the possibility of a remote trigger of the Younger Dryas event. Apart from the climatological implications this is important for high-precision cross-dating records of European temperature with East Asian records of summer monsoon strength such as speleothems.|