Hands-On, Minds-On Meteorology Description | Programming | Operation Pollution Description The pollution application allows the student to see how both natural and man-made aspects of the atmosphere combine to cause pollution. click for whole shot   Objectives The objective of this application is to show how pollution can change given varying wind speeds, pollution source concentrations, and atmospheric conditions. Programming Theory The theory is simple. The idea is to program a simple Gaussian Plume Model. The equation that computes Pollution concentration depends on distance, height of source, wind speed, and stability parameters. The last of these are computed off a table developed by Pasquill (1961) and used repeatedly. Assumptions Continuous emission of source downwind direction is not less than 1000m Pollutant is stable No removal of pollutant -- 100% reflection Gaussian distribution in crosswind and vertical Steady-state conditions (~1hr) Constant Wind Speed Constant wind direction with height Effect on wind shear on horizontal diffusion is neglected Dispersion parameters are independent on Z and function of x alone Averaging time of all quantities is the same Rural Area Pollutant is SO2 Equations Gaussian Plume Model Pasquill Table Meteorological conditions defining Pasquill turbulence types Surface Wind Speed (m/s) Daytime Insolation Nighttime Insolation Strong Moderate Slight Thin Overcast Cloudiness <2 A A-B B - - 3 AB B C E F 4 C B-C C D E 5 C C-D D D D >6 C D D D D (More information on both of these can be found in Lyons and Scott: Principles of Air Pollution Meteorology -- pg. 95 Fig. 3.19) Other Graphics: The plume is simply a gray blob with varying transparency. For each point in the x-y plane (top) or x-z plane (bottom), the pollution is calculated. That point is then given a transparency value (0 = totally invisible, 255 = totally opaque). Right now, the transparency value equals the pollution value, and for pollution > 255, the transparency value is set to 255. Operation Running the Program Click the 'Pollution' icon. Change the source volume and wind speed by sliding the appropriate scrollbars. Change the Solar Radiation / Atmospheric condition by choosing the appropriate radio button. Stability changes based on changes in both solar/atmospheric conditions but also wind speed. Change the stack height by clicking and dragging the arrow next to the top of the stack in the lower window. (Range: 10-40m) Click and drag on the guy in the lower half of the window to change his distance from the smoke stack. (Range 25-125m) Enable the Graphing Tool by click the appropriate button. Extra Knowledge N/A Department of Atmospheric Sciences University of Illinois at Urbana Champaign Created by Dan Bramer: Last Modified 07/27/2004 send questions/comments to bramer@atmos.uiuc.edu