Glaciations and palaeoclimate of the last millennium in the Drongtso Lungpa Co Valley, southeastern Tibetan Plateau, based on cosmogenic ¹⁰Be exposure dating and glacier modelling

The temperate glaciers of the southeastern Tibetan Plateau (TP) are highly sensitive to climate change. In this study, 11 exposure ages were obtained from the Drongtso Lungpa Co Valley in the southeastern TP to constrain the timing of glaciations during the late Holocene. The 10Be exposure dating method was employed to reconstruct the palaeoclimate during glaciations, using coupled mass balance and ice flow models. The results uncovered three typical glacial events, constrained at 1002 & PLUSMN; 190 CE, 1623 & PLUSMN; 149 CE, and 1874 & PLUSMN; 116 CE. The modelling results showed that the temperature during the glacial event at 1002 & PLUSMN; 190 CE was 2.8-1.8 degrees C lower than today, while the precipitation amounts were 20-70 % higher than the present-day level. The modelled temperature during the 1623 & PLUSMN; 149 CE event was 1.5-0.6 degrees C lower than today, while the modelled precipitation amounts were 10-50 % higher than today. The modelled temperature during the 1874 & PLUSMN; 116 CE event was 1.5-0.75 degrees C lower than today, while the modelled precipitation amounts were up to 30 % higher than the present-day level. A comparison with the ages of glacial events of the southern TP indicated that the timing of glacial variations in the Drongtso Lungpa Co Valley kept pace with other places in the southern TP. These other places experienced glacial events during similar to 950-1200 CE, similar to 1200-1700 CE, and similar to 1750-1900 CE.