High- and low-latitude forcings on regional hydroclimate variability in Northeast China during Marine Isotope Stage 2

Abstract

The scarcity of well-dated, highly temporally resolved, paleoclimate records during the Marine Isotope Stage (MIS) 2 in Northeast (NE) China limits our understanding of the hydroclimate history in East Asian monsoon (EAM) region under different boundary conditions and the prediction of future hydroclimate changes. Meanwhile, it has not been comprehensively investigated how high- and low-latitude forcings, as crucial driving factors of global climate change, impact regional hydroclimate on various timescales during the MIS 2. This study applies phytolith-based principal component 1 scores, sum proportions of grain size-based end-members 2 and 3, and values of loss-on-ignition at 550 °C from the Dadong profile, to provide new evidence of hydroclimate changes during the MIS 2 in NE China. The results suggest that the regional humidity was low during the Last Glacial Maximum, and gradually increased during the subsequent Last Deglaciation. Additionally, the typical climate pattern of “warm-humid/cold-dry” in the EAM region was showed during a series of millennial oscillations. Combined with multiple records from NE China, it is observed that the orbital-scale hydroclimate changes during the MIS 2 were relatively consistent in different regions, and were mainly regulated by the ice sheet extents under the control of Northern Hemisphere high-latitude summer insolation. On the millennial scale, however, the hydroclimate changes suggested significant asynchrony or even anti-phase, indicating that the climate pattern may not always be similar to the typical EAM pattern. We propose that a series of sea-land-air interactions under the coupling of North Atlantic Deep Water activities in high latitudes and El Niño-Southern Oscillation in low latitudes, may be responsible for this complicated pattern. This study provides new insights into the climate evolution in NE china and its relationship with the high- and low-latitude forcings, which is beneficial for the explanation of mechanisms behind climate variability in this region.