Browsing by Author "Nugent, Paul Winston"

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Deployment of the third-generation infrared cloud imager : a two-year study of Arctic clouds at Barrow, Alaska
(Montana State University - Bozeman, College of Engineering, 2016) Nugent, Paul Winston; Chairperson, Graduate Committee: Joseph A. Shaw
Cloud cover is an important but poorly understood component of current climate models, and although climate change is most easily observed in the Arctic, cloud data in the Arctic is unreliable or simply unavailable. Ground-based infrared cloud imaging has the potential to fill this gap. This technique uses a thermal infrared camera to observe cloud amount, cloud optical depth, and cloud spatial distribution at a particular location. The Montana State University Optical Remote Sensor Laboratory has developed the ground-based Infrared Cloud Imager (ICI) instrument to measure spatial and temporal cloud data. To build an ICI for Arctic sites required the system to be engineered to overcome the challenges of this environment. Of particular challenge was keeping the system calibration and data processing accurate through the severe temperature changes. Another significant challenge was that weak emission from the cold, dry Arctic atmosphere pushed the camera used in the instrument to its operational limits. To gain an understanding of the operation of the ICI systems for the Arctic and to gather critical data on Arctic clouds, a prototype arctic ICI was deployed in Barrow, AK from July 2012 through July 2014. To understand the long-term operation of an ICI in the arctic, a study was conducted of the ICI system accuracy in relation to co-located active and passive sensors. Understanding the operation of this system in the Arctic environment required careful characterization of the full optical system, including the lens, filter, and detector. Alternative data processing techniques using decision trees and support vector machines were studied to improve data accuracy and reduce dependence on auxiliary instrument data and the resulting accuracy is reported here. The work described in this project was part of the effort to develop a fourth-generation ICI ready to be deployed in the Arctic. This system will serve a critical role in developing our understanding of cloud cover in the Arctic, an important but poorly understood region of the world.
Wide-angle infrared cloud imaging for cloud cover statistics
(Montana State University - Bozeman, College of Engineering, 2008) Nugent, Paul Winston; Chairperson, Graduate Committee: Joseph A. Shaw
The Infrared Cloud Imager (ICI) is a radiometrically calibrated thermal infrared imaging instrument currently in development at Montana State University to measure cloud cover statistics. This instrument was developed originally as part of a joint U.S.-Japan effort to study the arctic atmosphere. The ICI provides localized high-resolution data relative to satellites images and, in contrast to visible imaging systems, provides continuous day and night operation. While the original instrument proved the capabilities of using radiometrically calibrated thermal infrared images to produce cloud coverage measurements, this instrument was limited. These limits were primarily the instrument's large size, relatively high cost, narrow field of view, and need to recalibrate the camera for each image. The work presented here covers work conducted to develop two prototypes of a second-generation ICI instrument, and the work which laid the groundwork for the development of a fully deployable version of these systems. These systems are to be used to measure cloud cover statistics for the characterization of optical communication paths by the Optical Communication Group at NASA JPL.