The United States Network for Isotopes in Precipitation (USNIP) is collaboration between the University of Alaska Anchorage and the University of Colorado at Boulder. This project constitutes an effort to provide d 18 O and d D isotopic values for ~80 sites across the United States using the National Atmospheric Deposition Program (NADP) sampling stations. This project contributes to the IAEA/WMO Global Network for Isotopes in Precipitation (GNIP) program and cooperates with other national networks including the Canadian Network for Isotopes in Precipitation.
Determining the isotopic composition of modern precipitation provides the fundamental background required for hydrologic studies. As part of the GNIP database, this data will be accessible to the scientific community for regional, continental, and global studies. Isotopes in precipitation provide a framework for surface and groundwater hydrology, synoptic climatology at multiple temporal and spatial scales, plant-water interactions, and paleoclimate applications. This research is supported by the Earth System History (ESH) program of the National Science Foundation.
R. W. Vachon, J. W. C. White, E. Gutmann, and J. M. Welker. 2007. Amount-weighted annual isotopic (d18O) values are affected by the seasonality of precipitation: A sensitivity study. Geophysical Research Letters, 34: L21707, doi:10.1029/2007GL030547.
Methods details for Welker et al. EOS paper (submitted)