Stable isotope composition of dew measured from 2014 to 2018 in Namibia, France, and the United States

As a supplementary or sometimes the only water source in dry regions, dew plays a critical role in the survival of organisms in such environments. The new hydrological tracer 17O-excess, with almost sole dependence on relative humidity, provides a new way to distinguish the evaporation processes and reconstruct the paleoclimate. Up to now, there is no daily dew isotope record on δ2H, δ18O, δ17O, d-excess, and 17O-excess. To fill this gap, here we collected daily dew (n=114) between July 2014 and April 2018 from three distinct climatic regions (i.e., Gobabeb-Namib Research Institute in the central Namib Desert with desert climate, Nice in France with Mediterranean climate, and Indianapolis in the central United States with humid continental climate). The isotopic composition (δ2H, δ18O, and δ17O) of dew was simultaneously analyzed using a Triple Water Vapor Isotope Analyzer (T-WVIA) based on Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) technique, and then d-excess and 17O-excess were calculated. The latitude, longitude, and elevation as well as three meteorological factors including temperature, relative humidity (RH), and vapour-pressure deficit (VPD) of the three collection sites were also provided here. This report presents daily dew isotope dataset under three different climatic regions. It is useful for researchers to use it as a data reference when studying global dew dynamics and dew formation mechanisms