A proposed global atmospheric monitoring network based on standard stars

The feasibility of developing a network of telescopes to monitor the composition of the nighttime atmosphere using stellar spectrophotometry is explored. Spectral measurements of the extinction of starlight by the atmosphere would allow, for instance, quantification of aerosol, cloud, water-vapor, and ozone levels over the full range of elevation and azimuth. These measurements, when combined with data from solar spectrophotometry derived from other instruments, would provide continuous day/night monitoring of the atmospheric composition from the ground. The foundation for such an effort would be a set of stable standard stars with known top-of-the-atmosphere spectral irradiances traceable to international standards based on the SI system of units. Fully automated, reliable, easily maintained and highly costeffective replicas of the spectrophotometric telescope used to calibrate the standard stars can be deployed worldwide at sites such as atmospheric and astronomical observatories.