The Qinghai-Xizang Plateau (QP), often referred to as the "Asian Water Tower", is a vital source of water for nearly two billion people. Understanding how precipitation patterns in this region will change in the coming decades is crucial for water resource management and climate adaptation. However, projecting near-term precipitation changes has been challenging due to significant uncertainties in climate models.
A new study published in Atmospheric and Oceanic Science Letters addresses this issue by analyzing near-term (2026–2055) precipitation projections for the QP using 100 ensemble members from the MPI-ESM climate model. The research team—from the Chinese Academy of Meteorological Sciences, China—found that while the QP is expected to experience an overall wetting trend, there is considerable uncertainty in precipitation trends across the southern QP.
"The southern Qinghai-Xizang Plateau exhibits a complex east–west dipole pattern in precipitation changes, which is strongly influenced by the phase transition of the Interdecadal Pacific Oscillation," explains the corresponding author of the study, Prof. Jian Li. "A positive Interdecadal Pacific Oscillation phase transition tends to enhance precipitation in the eastern part of the southern QP while suppressing it in the western part, and a negative phase transition has the opposite effect."
This uncertainty has made it difficult for policymakers to make informed decisions about water resource management. To address this, the researchers applied a method to adjust the Interdecadal Pacific Oscillation phase transition in the simulation members, which significantly improved the consistency of precipitation projections.
"By aligning the Interdecadal Pacific Oscillation phase transitions across the ensemble members, we were able to increase the consistency of our projections from 50% to 70% and 55% for positive and negative Interdecadal Pacific Oscillation phase transitions, respectively," says Dr. Yin Zhao, lead author of the study.
The findings of this study have important implications for adaptive water resource management in the QP region. "Accurate simulation of Interdecadal Pacific Oscillation phase transitions is critical for improving near-term precipitation projections," emphasizes Prof. Jian Li.
