Aerial Thermography of Pond Recirculation Plumes
Thermal signatures offer a myriad of industrial uses. Much of that utility is in applications where visible band imagery or visual assays don't sense significant "Delta-Anything" (meaning that human visual acuity is of little or no value in differentiating phenomana in a matter).
The following image is an orthogonal (vertical) aerial thermograph of a landscape pond in a residential subdivision. Water is circulated from the pond so that it may be filtered and otherwise processed, then returned to the pond via pump to nozzles located beneath the water's surface. In the event that a segment of the return system is inoperative-for whatever reason-it can be very difficult to diagnose or even recognize the failure.
Aerial thermography can very quickly, effectively, and affordably assay an enormous number of such features, even geotagging the images with Latitude, Longitude, water surface elevation, and water surface temperature readings.
The following graphic is a page from a standard software report on the image above.
Four plumes are incorporated into this report page, and they are labeled Plumes A through D. The context for those plumes is also assayed. The first (large) Histogram beneath the image is that for the context of the plumes and is useful in determining the baseline temperature of the pond's surface served by the associated returns. In this case, the average temperature is 2.4° Centigrade, though this is not a calibrated temperature (it's accurate primarily for comparison, not for absolute measurement-though it certainly can be when forensically prudent).
The plumes average 2.9° Centigrade-about half of a degree warmer than the context-and this metric too is not calibrated but is useful for comparison. That temperature is produced by the warmth of the ground and equipment the processed water has experienced during it's experiences in the filter, pumps, etc. This collected warmth is mitigated by the return trip beneath the water (often the pipes may actually not be buried but simply submerged) and the water's ascent to the surface-which itself may be variable between nozzles.
The individual histograms demonstrate the thermal nature of each plume and are intriguing, to say the least. Although they are relatively homogenous in terms of their mean (average), their skewness and kurtosis are substanially distinguished. This may be due to the variables mentioned in the previous paragraph.
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