there is an easy to understand scientific explanation for this, (I couldn't see any sprayers)
moisture is not evenly distributed through the air for several reasons. Sometimes, when conditions are right we can see the water vapor in the patches of high moisture condense. We call those clouds. The irregular distribution of moisture is there even when conditions are not right for precipitation into liquid state ie clear skies. When a plane flies through the sky it can hit these patches (basically invisible clouds) and adds moisture, producing a control, in the lower moisture areas it does not. Science, baby!
Here is a video from 1944 of the phenomenon.
http://www.youtube.com/watch?v=wfOre...layer_embedded
Sorry I haven't been able to watch any more "what in the world . ." yet. All my free time has been spent on MTS 59.
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