IRSI

The infrared sky imager (IRSI) measures cloud fraction and precipitable water vapor. The IRSI captures hemispheric sky images and provide time series retrievals of fractional sky cover during both day and night. The instrument provides diurnal sky imagery in the mid-infrared atmospheric window and imagery during daylight hours in the visible wavelengths for cloud retrievals. The software automatically identifies cloudy and clear regions and calculates fractional sky cover.