The National Science Foundation (NSF) Ultraviolet (UV) Monitoring Network provides data on ozone depletion and the associated effects on terrestrial and marine systems. Data are collected from 7 sites in Antarctica, Argentina, United States, and Greenland. The network is providing data to researchers studying the effects of ozone depletion on terrestrial and marine biological systems. Network data is also used for the validation of satellite observations and for the verification of models describing the transfer of radiation through the atmosphere.