Remote sensing of cooling tower and factory stack plumes may provide unique information on the constituents of the plume. Potential information of the power generated by the plant or the chemical composition of the factory products may be gathered from thermal emission and absorption in the infrared band, or from scattering of light in the visible band. A new model for generating synthetic images of plumes has been developed using DIRSIG, a radiometrically based ray-tracing code. Existing models that determine the characteristics of the plume (constituents, concentration, particulate sizing, and temperature) are used to construct the plume in DIRSIG. The effects of scattered light using Mie theory and radiative transfer, as well as thermal self-emission and absorption from within the plume, are modeled for different regions of the plume. Both single and multiple scattering methods are available. The ray-tracing accounts for radiance from the plume, atmosphere, and background. ' Synthetic generated images of a cooling tower plume, composed of water droplets, and a factory stack plume, composed of methyl chloride, are produced for visible, MWIR, and LWIR bands. Images of the plume from different sensor platforms are also produced. Observations are made on the interaction between the plume and its background and possible effects for remote sensing. Images of gas plumes using a hyperspectral sensor are illustrated. Several sensitivity studies are done to demonstrate the effects of changes in plume characteristics on the resulting image. Inverse algorithms that determine the plume effluent concentration are tested on the plume images. A validation is done on the gas plume model using experimental data collected on a SF6 plume. Results show the integrated plume model to be in good agreement with the actual data from five to one hundred meters from the stack exit. The scattering models are tested against MODTRAN. The validity and limitations of these models are discussed as a result of these tests. Finally two atmospheric scattering phenomena are illustrated to demonstrate qualitatively the scattering models.
Library of Congress Subject Headings
Cooling towers; Smoke plumes; Remote sensing--Industrial applications
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Kuo, S. Didi, "Synthetic image generation of factory stack and water cooling tower plumes" (1997). Thesis. Rochester Institute of Technology. Accessed from
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