Late Holocene coupled moisture and temperature changes on the northern Tibetan Plateau

Abstract

The northern Tibetan Plateau involves complex interactions between the mid-latitude westerly circulation and the subtropical Asia monsoon circulation, acting as a bridge communicating high and low latitude climatic processes. Previous studies from the region suggest relatively wet conditions in cold periods during the late Holocene, for instance, the Little Ice Age (LIA). However, the inference of such temperature-moisture association is subject to the large uncertainty in lacustrine 14C chronology, due to the particularly large lake reservoir effect in the region. Here we take a different approach by reconstructing paired temperature and moisture records from the same sediment cores to assess the temperature-moisture association, independent of chronology uncertainty. We use alkenone indices UK′37 and %C37:4 to reconstruct high resolution temperature and moisture changes simultaneously from two lakes in the Qaidam Basin, northern Tibetan Plateau, over the last ∼2500 years. Characterized by marked climatic variability, our paired records confirm the warm-dry and cold-wet association in arid northwestern China during the late Holocene, opposite to the warm–wet and cold–dry association in subtropical Asian monsoonal regions. Our moisture records further suggest substantially drier conditions during the Medieval Warm Period (MWP) than the current warm period. Lastly, the temperature and moisture changes inferred from our records can be well correlated with solar irradiance changes, suggesting a possible link between solar forcing and natural climate variability during the late Holocene on the northern Tibetan Plateau.