Characteristics of hydrogen and oxygen stable isotopes in precipitation and the environmental controls in tropical monsoon climatic zone

摘要

The characteristics of hydrogen and oxygen stable isotopes and their environmental controls were investigated in five regions which were influenced by tropical monsoon climate from January 2015 to December 2016. The result showed that the local meteoric water line (LMWL) for each region deviated from the global meteorological water line (GMWL) in varying degrees and difference existed between wet and dry seasons. The isotopic composition and d-excess on temporal and spatial scales varied considerably among stations, showing the difference of the controlling air masses and the distance of water transport. Generally, the heavy isotopes depleted along the direction of monsoon flow. The influences of temperature and precipitation amount were studied by monadic regression analysis and bivariate regression analysis, the coefficients for both meteorological parameters were calculated. The "precipitation amount effect" was obvious in the whole area, while both positive and negative correlations were observed between temperature and isotopes, which showed the synergy of temperature and precipitation to stable isotopes. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.