Tibetan Plateau Precipitation Modulated by the Periodically Coupled Westerlies and Asian Monsoon

Abstract

Knowledge of decadal-centennial-scale precipitation cycles is important for predicting the status of water resources and thus food security in the region influenced by the “Asian Water Tower” (the Tibetan Plateau, TP). However, the drivers of these precipitation cycles in the TP remain unclear. Here we present a 1,656-years (5-years-resolution) mean annual precipitation record reconstructed by fossil pollen assemblages from the annually laminated sediments of a lake in the TP interior. The record reveals three dominant cycles, with lengths of ∼200-, ∼88-, and ∼60-years, associated with changes in the Westerlies and the Asian monsoon. These precipitation cycles suggest that the current high precipitation in the TP interior results from the superposition of cyclic highs in precipitation, and this trend may continue for the next several decades.