Comment on tc-2022-43

Abstract

The δ18O of gaseous oxygen in ice core air bubbles (δ18Obub) has been widely used for reconstruction of climate changes in polar glaciers. Yet, less is known about its climatic implication in alpine glaciers as the lack of continuous record. Here, we present a long-term δ18Obub record from the Tanggula glacier in the central Tibetan Plateau (TP). It shows that there is a good correlation between the variation of the δ18Obub in this alpine ice core and the accumulation or melting of the glacier. The more developed the firn layer on glacier surface, the more positive the δ18Obub is. The more intense the glacier melting, the more negative the δ18Obub is. Combined with the chronology of the ice core air bubbles, we reconstructed the glacier variations since the late Holocene in the central TP. It showed that there were four accumulation and three deficit periods of glaciers in this region. The strongest glacier accumulation period was from 1610–300 B.C., which corresponding to the Neoglaciation. The most significant melting period was the last 100 years, which corresponding to the recent global warming. During the Little Ice Age, glacier accumulation in the central TP was not significant, and even short deficit events occurred. Comparisons of the late Holocene glacier variation in the central TP with hemispheric glacier and climate variations showed that it was closely related to the North Atlantic Oscillation.