Jet Contrail Identification Using the AVI-IRR Infrared Split Window

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  • 1 Naval Environmental Prediction Research Facility, Monterey, California
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Abstract

Advanced Very High Resolution Radiometer channels 4 (11 μm) and 5 (12 μm) are used together to produce images which greatly enhance contrails. Four steps are required: 1) select coregistered digital data sets from the two channels; 2) convert each raw grayshade to a calibrated brightness temperature; 3) substract corresponding channel 5 temperatures from channel 4 temperatures, creating a field of temperature differences; and 4) display these differences as an image. On the image, the earth's surface and all but thin ice clouds are associated WM small temperature differences (of about −1 to +2 K in the midlatitudes) and appear dark. Newly formed contrails and other thin ice clouds, which are associated with larger temperature differences (of about +2 to +6 K in the midlatitudes), appear bright and stand out well against a dark background.

Abstract

Advanced Very High Resolution Radiometer channels 4 (11 μm) and 5 (12 μm) are used together to produce images which greatly enhance contrails. Four steps are required: 1) select coregistered digital data sets from the two channels; 2) convert each raw grayshade to a calibrated brightness temperature; 3) substract corresponding channel 5 temperatures from channel 4 temperatures, creating a field of temperature differences; and 4) display these differences as an image. On the image, the earth's surface and all but thin ice clouds are associated WM small temperature differences (of about −1 to +2 K in the midlatitudes) and appear dark. Newly formed contrails and other thin ice clouds, which are associated with larger temperature differences (of about +2 to +6 K in the midlatitudes), appear bright and stand out well against a dark background.

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