The Global Network of Isotopes in Precipitation (GNIP) is a worldwide isotope monitoring network of hydrogen and oxygen isotopes in precipitation, initiated in 1960 by the International Atomic Energy Agency (IAEA) and the World Meteorological Organization (WMO), and operates in cooperation with numerous partner institutions in Member States.
The analysis of the temporal and spatial variations of environmental isotopes in precipitation (mainly oxygen-18 and deuterium) provides basic data for the use of isotopes in hydrological investigations within the scope of water resources inventory, planning and development.
GNIP is available through the WISER portal (Water Isotope System for Data Analysis, Visualization and Electronic Retrieval). Participation in the GNIP is possible by registering on the Isotope Hydrology Collaboration Site.