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BIOMICROMETEOROLOGY GROUP. CHARACTERIZING COLD AIR POOL DYNAMICS USING THERMAL IMAGERY. PRESENTED BY CHRIS JOHNSON. Photo Credit: The University of Utah. DESIGN OF EXPERIMENT. SODAR. THERMAL IMAGERY TO MAP COLD AIR POOL DYNAMICS.
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BIOMICROMETEOROLOGY GROUP CHARACTERIZING COLD AIR POOL DYNAMICS USING THERMAL IMAGERY PRESENTED BY CHRIS JOHNSON
DESIGN OF EXPERIMENT SODAR
THERMAL IMAGERY TO MAP COLD AIR POOL DYNAMICS Each pixel of temperature information will be associated with a position on the Earth and an elevation. But first the thermal imagery must be filtered, georeferenced, and orthorectified.
GEOREFERENCING THERMAL IMAGERY Known Object and Location • Identify objects in the image • Obtain accurate locations • Use known objects as Ground Control Points Ground Control Point
ORTHORECTIFICATION Data Gap
VALIDATION – Temperature Profile • Basic Functions: • Emits a sound pulse • Measures properties of sound backscattered from turbulent fluctuations • Emitted pulse frequency • Backscattered sound frequency • Intensity of backscattered sound • Relationship to IR Measurements: • Atmospheric Structure Parameters • Refractive Index Structure Parameter(CN2) • Temperature Structure Parameter (CT2) • Intensity related to CN2 • CN2 related to CT2 • CT2 directly calculated from temperature gradient
VALIDATION – Cold Air Pool Depth Assumption: The depth of the cold air pool is equal to the inversion height. Backscatter Intensity Potential Temperature ABL Conditions for Plot: Weak wind, surface radiatively cooling. Plot Credit: Beyrich, F., 1997. Mixing Height Estimation from SODAR Data. Atmospheric Environment 31, 3941-3953.
DESIGN OF EXPERIMENT SODAR