Understanding the changing Arctic climate requires detailed knowledge of the spatial and radiative properties of Arctic clouds. However, quantifying the relationships between cloud temporal and spatial distribution and radiative impacts requires more continuous and accurate measurements. Important gaps in the capabilities of current satellite- and ground-based cloud sensors can be filled with an Arctic network of ground-based long-wave infrared cloud imagers. This project will deploy an Infrared Cloud Imager (ICI) to measure the spatial and temporal distribution and optical properties of Arctic clouds continuously (day and night) for a full annual cycle at Barrow, Alaska, while also developing a new, compact version of this unique instrument that will enable future operation of a network of autonomous cloud sensors throughout the non-coastal Arctic. ICI data will enable many studies on relationships such as cloud spatial-temporal variability and cloud radiative forcing. Broader impacts will include providing an immediately valuable data stream in a cross-agency cooperation between the NSF and the Department of Energy (DOE), helping to establish the long-needed capability of diurnal cloud amount measurements at the North Slope of Alaska facility in Barrow, Alaska, and providing unique cross-disciplinary training of graduate and undergraduate students in engineering and science.