water Article Isoscape of δ18O in Precipitation of the Qinghai-Tibet Plateau: Assessment and Improvement Yudong Shi 1, Shengjie Wang 1,* , Mingjun Zhang 1, Athanassios A. Argiriou 2 , Rong Guo 3, Yang Song 1 and Xiaofan Zhu 4 1 College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China;
[email protected] (Y.S.);
[email protected] (M.Z.);
[email protected] (Y.S.) 2 Laboratory of Atmospheric Physics, Department of Physics, University of Patras, GR-265 00 Patras, Greece;
[email protected] 3 Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China;
[email protected] 4 Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China;
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[email protected] Received: 6 November 2020; Accepted: 30 November 2020; Published: 2 December 2020 Abstract: The spatial distribution of stable water isotopes (also known as an isoscape) in precipitation has drawn increasing attention during the recent years. In this study, based on the observations at 32 stations, we assessed two widely applied global isoscape products (Regionalized Cluster-based Water Isotope Prediction (RCWIP) and Online Isotopes in Precipitation Calculator (OIPC)) at the Qinghai-Tibet Plateau (QTP) and then established an improved isoscape of oxygen isotopes in precipitation on a monthly basis using a regionalized fuzzy cluster method. Two fuzzy clusters can be determined, which is consistent using three meteorological data. The monthly isoscapes show the seasonal movement of high and low isotopic value regions across the QTP and reveal the influences of monsoon and westerly moisture. According to the cross validation, the δ18O in precipitation in the new monthly isoscapes for the QTP we propose performs better compared to the existing global products.