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Changes in the East Asian Summer Monsoon (EASM) precipitation intensity have been derived from loess-paleosol sequences and oxygen isotope (δ18O) records of well-dated stalagmites from several caves in China, and show that the strength of the EASM generally responds to changes in Northern Hemisphere (NH) summer insolation. In contrast, past continental air temperature dynamics are still poorly understood for this area, mainly due to the lack of paleotemperature records.
I here present a high-resolution record of East Asian air temperature over the past 130,000 years, derived from soil bacterial membrane lipids, i.e. branched glycerol dialkyl glycerol tetraethers (brGDGTs), preserved in a loess-paleosol sequence at the Mangshan section of the CLP. Distributional relationships of brGDGTs with both temperature and soil pH allows for direct comparison of our temperature record with precipitation-induced changes in soil pH. This reconstruction reveals that variations in monsoon precipitation consistently lag those in air temperature throughout the whole record at the dominant precession band, suggesting that northern hemisphere ice sheets may play an important role in modulating the response of EASM precipitation to insolation forcing. |