Stable isotope variations of daily precipitation from 2014-2018 in the central United States

Stable isotopes of hydrogen and oxygen (delta H-2, delta O-18 and delta O-17) serve as powerful tracers in hydrological investigations. To our knowledge, daily precipitation isotope record especially O-17-excess is rare in the mid-latitudes. To fill such knowledge gap, daily precipitation samples (n=446) were collected from June 2014 to May 2018 in Indianapolis, Indiana, U.S.A Triple Water Vapor Isotope Analyzer (T-WVIA) based on Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) technique was used to concurrently measure precipitation isotopic variations (delta H-2, delta O-8 and delta O-17). Meanwhile, O-17-excess and d-excess as second-order isotopic variables were calculated to provide additional information on precipitation formation and transport mechanisms. This study presents a four-year daily precipitation isotope dataset for mid-latitudes, and makes it available to researchers around the world who may use it as a reference for site comparisons and for assessing global hydrological models.