Of Mis6 East Asian Summer Monsoon Sub-orbital-scale Climate Change

The author reconstructs a high resolution climate record of East Asian monsoon during late penultimate glaciation (160~130kaBP), based on 10 dating ages and 658 data of stable isotopic compositions as well as stalagmites annual layers. The records illustrated characters of East Asian monsoon rapid climatic changes during the penultimate glaciation, which bears a very similar pattern to millennial scale changes during the last glaciation. This provides further evidence for a general relationship between high frequency variability of East Asian monsoon and the global events.In the processional scale, the stalagmites δ18O curve follows records from Antarctic ice core as well Chinese loess. The similarity suggests that global climate changes were driven by the orbital variability of 65N summer insolation. Based on the Dole effect, the hydrological cycle of low latitude ocean provides main source for precipitation of the East Asian summer monsoon.In the millennial scale, calcite δ18O records display a high-frequency oscillation. There are two extremely dry events as expressed in rapid positive shift in the stalagmites δ18O record. The ages are 138.7kaBP and 136.2kaBP, respectively. A magnitude of the stalagmite δ18O variability for the Heinrich events during the studied interval reaches 1.49% and 2.66%o, respectively, similar to that of the Heinrich-type events during the last glaciation from the stalagmite δ18O records in the same cave. In addition, there are 11 climate wet events as reflected by negative values of stalagmites δ18O that resemble SST variability in Atlantic region (40N). A amplitude of the stalagmite δ18O values averages 1.5%, which is similar to that of the Dansgaard-Oeschger events during the last glaciation. Under the millennial scale, stalagmites δ18O records appear high frequency and low amplitude(less than 0.5%o).The δ18O record from the last glacial and the penultimate glacial periods resemble processional orbital variability of 65N summer insolation and appear high frequency variability in the millennial-centennial scale. But the oscillations of the last glaciation show more large amplitude than that of the penultimate late glaciation. This implications that climate events during difference glaciation may be triggered by different factors.In the processional scale, stalagmite δ13C and δ18O record is a clear positive correlation during the penultimate glaciation, but a negative correlation during the last glaciation; in the millennial-centennial scale, stalagmite δ13C and δ18O record is a clear negative correlation during the penultimate glaciation and the last glaciation.