VARIABILITY IN THE INDIAN SUMMER MONSOON PRECIPITATION AND LAKE LEVELS IN EASTERN TIBET

The Indian summer monsoon (ISM) is the primary source of precipitation to the Tibetan Plateau. Surface waters and glaciers within the Third Pole Environment are the headwaters for some of the largest rivers throughout southern Asia. Predicting variability in the ISM is limited when reliant on modern monitoring data for a process that can have annual and decadal variability. Expanding on precipitation records using paleoclimate data makes it possible to track variability on a decadal scale. This study is using sediment cores and surface sediments to assess paleo precipitation and lake levels. Samples were collected from three small lakes in Eastern Tibet: Galang Co, Nir ‘Pa Co, and Paru Co in 2011 and 2015. Initial analyses include bulk density, organic carbon and total carbonate concentrations, and grain sizes while future work will focus on leaf wax isotopes for precipitation inferences. The 2011 core from Nir ‘Pa Co showed shifts in grain size and composition that indicate periods of wet and dry climate and correlate with other regional climate records that are focused on ISM precipitation variability. By expanding the record with additional cores, we aim to provide a more thorough assessment of decadal variability in the ISM. Shifts in ISM is relevant for future climate predictions and management in light of changing precipitation levels and reservoir reserves.