Discharge of effluent gas is an inescapable byproduct of many physical processes. The type or characteristics of the discharge potentially indicate the nature of the process. Observation of factory stack gases, for example, may indicate the level of pollutants being emitted into the atmosphere or the nature of the process being carried out in the factory. In this work, we have developed an improved model of plume dispersion suitable for synthetic image generation (SIG) applications. The technique partially utilizes a new EPA model that discretizes the plume into a series of small puffs (rather than the implicit mono lithic form used in prior regulatory and SIG work) . The locations and sizes of these puffs are then perturbed to approximate the location and size of the plume at any given instant and to incorporate the effects of high-frequency wind fluctuation. We have incorporated an improved model for plume temperature calculation and a more accurate method for calculating the aggregate self-emitted radiance for rays traced through the plume. We have also developed novel techniques simulating the interaction of plumes with their surroundings. Our primary application of this work is the simulation of heating of roofs by vents of various types. The technique can also be used to simulate vehicle exhaust and other similar effects. Finally, we have established a protocol for future modification of plume calculation algorithms by end-users of the Digital Imaging and Remote Sensing Image Generation (DIRSIG) code and implemented the present methods as prototypes. This Generic Plume Interface (GPI) protocol defines a message set used to request that the plume effect along a particular ray be calculated and to communicate back to DIRSIG the concentrations and temperatures along the ray. With this construct in place, any off-the-shelf tool can be interfaced with DIRSIG through a simple user-written interpreter to make appropriate inputs to the tool for each ray and to translate the output into the proper format.

Library of Congress Subject Headings

Smoke plumes--Mathematical models; Air--Pollution--Measurement--Mathematical models; Atmospheric diffusion--Mathematical models; Remote sensing--Data processing; Imaging systems

Publication Date


Document Type


Department, Program, or Center

Chester F. Carlson Center for Imaging Science (COS)


Schott, John


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