Penetration of the Westerlies into the Northern Tibetan Plateau since the Late Pleistocene

Abstract:

It is currently suggested that climate change on the Tibetan Plateau has influenced alternately by the monsoon and the Westerlies at glacial-interglacial scale to decadal scale. However, the mechanisms driving climate change in the Tibetan Plateau remain unclear, since the extent of individual atmospheric systems has not yet been clearly defined because of the lack of a sufficient number of high quality paleoclimatic records with implicit proxies. This is especially true in the northern Tibetan Plateau where only a few short ice core and paleolimnological records are available. Here we present records of precipitation hydrogen isotopes (δDP) based on compound specific hydrogen isotope ratios of sedimentary leaf waxes at three lakes, Lake Qinghai, Lingge Co and Bangong Co on the northern Tibetan Plateau to investigate how the monsoon and the Westerlies influenced climate change since the Late Pleistocene. The δDP records at Lake Qinghai on the Northeastern TP and Bangong Co at the Northwestern TP show general monsoon influence during the Holocene. The δDP record at Lingge Co in the central northern TP show different patterns, implying that the lake was mostly influenced by the local water vapor recycling or the Westerlies.

Statistical analysis on modern precipitation isotope data, river water isotope data support that the isotope variability at Lingge Co reflects the Westerlies influence.

The δDP records at the three lakes suggest that the Westerlies prevailed in the central North TP, while the monsoon dominated in the eastern and western TP since the Late Pleistocene. More records are required to delineate the extent of the monsoon and the Westerlies on the TP during the Holocene.