East Asian monsoon variations directly recorded in the Greenlandic North-GRIP ice core

Abstract

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 (north-central Greenland). The East Asian Winter Monsoon (EAWM) 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 EAWM. Further, variations of the East Asian Summer Monsoon (EASM) strength are coincident with changes of the Ca2+/particle ratio at North-GRIP. In light of these findings and taking d18O as a proxy for North Atlantic temperature we investigate the rapid climatic transitions during the last glacial period (Dansgaard-Oeschger events). We discuss differences between the changes of EAWM, EASM, and North Atlantic temperature regarding their timing at these rapid transitions; this can be done with unforeseen accuracy because all proxies are from the same archive and do not underlie relative dating uncertainties. Furthermore we find that before 75ka BP (i.e. before the MIS 4/5-transition) atmospheric circulation patterns in the northern hemisphere as well as teleconnections between North Atlantic circulation and the East Asian Monsoon system must have been substantially different. They underwent considerable reorganisation, which may be linked to the build up of large ice sheets in the northern hemisphere during this time