NRL operates a network of of instruments making continuous measurements of middle atmospheric water vapor (at 22 GHz), ozone (at 110 GHz), and chlorine monoxide (at 278 GHz). The measurements are made from Lauder, New Zealand (H2O and O3), Mauna Loa and Mauna Kea, Hawaii (H2O, O3, and ClO), Table Mountain, California (H2O) and Scott Base, Antarctica (ClO). Most of measurements have been made since the early or mid-1990's and are being continuously updated to take advantage of of improvements in microwave technology. The data is used for satellite validation, studies of diurnal variations, seasonal variations, and multi-decadal trends. The measurements are made at sites of the international Network for the Detection of Atmospheric Composition Change (NDACC), where coincident measurements of other atmospheric constituents are available in a shared data base.