OH Pepsios

An ultraviolet spectrometer of Pepsios design has been constructed and used for measurements of the vertical column abundance of atmospheric hydroxyl. Ground-based observations are made of the spectroscopic absorption of sunlight by OH at 3081.7 Å. The measurements are of relevance to the problem of stratospheric ozone. The spectrometer is a series arrangement of four pressure-scanned Fabry-Perot etalons with vernier spacer ratios. The spectral resolution of 0.06 cm−1 permits the identification and measurements of the sharp absorption feature from cool terrestrial OH against the solar background. The observations from Fritz Peak Observatory, Colo., are presently contributing to a new data base on this atmospheric trace constituent which should be of importance in the understanding of middle atmospheric photochemical processes.