An Infrared Sky Imager for the Atmospheric Radiation Measurement Program Climate Research Facility

At the U.S. DOE's Atmospheric Radiation Measurement (ARM) Program Climate Research Facility, fractional sky cover has only been reliably determined during daytime hours utilizing the Total Sky Imager (TSI). Measurement of nighttime sky cover has long been a critical programmatic gap in ARM's observational data set and is an important factor in understanding the life cycle of clouds. It is recognized that infrared sky imaging technology has held great promise in closing this gap. In addition, this technology has the distinct advantage that its ability to characterize clouds is identical for day or night conditions. Requests for proposals were issued for a commercially-available infrared sky imager that resulted in the purchase of a Solmirus Corporation All Sky Infrared Visible Analyzer (ASIVA) and deployment at the ARM Southern Great Plains site. The instrument captures diurnal, hemispheric images of the sky in both the infrared and visible spectrum and provides values of fractional sky cover utilizing the radiometrically-calibrated data. Correlations between the ASIVA and TSI measurement methods will be discussed in this poster paper as well as additional analysis techniques being developed to improve this correlation.