Arctic Cloud Infrared Imaging

16 July 2012 - 31 July 2014

Lead Scientist: Joseph Shaw

Observatory: nsa, nsa

The 3rd-generation Infrared Cloud Imager (ICI) instrument was deployed close to the Great White facility at the North Slope of Alaska site and operated as autonomously as possible. The ICI instrument was operated 24 hours per day, 7 days per week, obtaining one cloud image at a user-selected interval that varied from approximately 1 minute and up. Typical operation was to obtain one image in a 1-5-minute period. At interesting periods, a high-temporal-resolution mode was employed, during which the imager acquired one image every few seconds. This mode was usually continued for several tens of minutes. The radiometrically calibrated thermal sky images were processed to remove atmospheric emission (using ARM-measured precipitable water vapor and air temperature). The resulting images allowed identification of cloud and no-cloud pixels in each image, and also estimation of the cloud optical depth for each cloudy pixel. These image sequences were processed to produce histograms of cloud fraction by season and month. A particularly noteworthy product of this campaign was separate cloud histograms for daytime and nighttime, focusing on the ICI's unique ability (relative to a visible imager) to obtain measurements with unchanging sensitivity during day and night.

Timeline

2016

Shaw JA. 2016. Arctic Clouds Infrared Imaging Field Campaign Report. Ed. by Robert Stafford, DOE ARM Climate Research Facility. DOE/SC-ARM-16-002. 10.2172/1248496.

2013

Shaw J and P Nugent. 2013. Infrared Cloud Imager Measurements at Barrow, Alaska. Presented at 4th Atmospheric System Research (ASR) Science Team Meeting. Potomac, MD.


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Campaign Data Sets

IOP Participant Data Source Name Final Data
Joseph Shaw Infrared Cloud Imager Order Data