Abstract: | Whether climatic changes in high latitudes of the Northern Hemisphere since the last glaciation have effects on the Tibetan
Plateau monsoon, and the variation characteristics of the Plateau monsoon itself are still not solved but of great significance.
The 22-m high-resolution loess-paleosol sequence in the Hezuo Basin on the northeastern Tibetan Plateau demonstrates that
the Plateau winter monsoon experienced a millennial variation similar to high latitude Northern Hemisphere, with cold events
clearly correlated with Heinrich events but less for the warm events (Dansgarrd-Oeschger events). It may indicate that the
climate system at high latitudes in the Northern Hemisphere had played an important role in both the Plateau monsoon and the
highlevel westerlies. On 104 year scale, there are two distinct anomalous changes, which are not found in the records from high latitude northern hemisphere,
revealed by the loess grain size in the Hezuo Basin. One is that there was a considerable grain size increase at ∼36 kaBP,
suggesting an abrupt enhancement of the Plateau winter monsoon at that time; the other is that, during 43–36 kaBP, the grain
size decreased distinctly, indicating a notable weakening of the Plateau winter monsoon around that period. Both of the two
anomalies suggest that the Tibetan climate may have been controlled by some other factors, besides the high latitude climatic
changes in the Northern Hemisphere. |