From: Martin Shough <parcellular.nul> Date: Fri, 23 Dec 2011 09:51:21 -0000 Archived: Fri, 23 Dec 2011 10:59:16 -0500 Subject: Tornado And Hail Frequency Vs. Day Of The Week Dear List There have been some claims over the years that types of UFO reporting might vary with the day of the week. I recall in particular John Keel's "Wednesday phenomenon". If this was ever rigorously tested I'm not aware of it, nevertheless it's intriguing that tornado and hail activity does proveably follow such a law and that there may be a mechanism to explain why. Perhaps other types of atmospheric phenomena could have a similar anthropogenic signature? ----- Source: PhysOrg.Com http://tinyurl.com/c5a653v December 22, 2011 JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116, D20211, 14 PP., 2011 doi:10.1029/2011JD016214 Abstract This study shows for the first time statistical evidence that when anthropogenic aerosols over the eastern United States during summertime are at their weekly mid-week peak, tornado and hailstorm activity there is also near its weekly maximum. The weekly cycle in summertime storm activity for 1995-2009 was found to be statistically significant and unlikely to be due to natural variability. It correlates well with previously observed weekly cycles of other measures of storm activity. The pattern of variability supports the hypothesis that air pollution aerosols invigorate deep convective clouds in a moist, unstable atmosphere, to the extent of inducing production of large hailstones and tornados. This is caused by the effect of aerosols on cloud drop nucleation, making cloud drops smaller and hydrometeors larger. According to simulations, the larger ice hydrometeors contribute to more hail. The reduced evaporation from the larger hydrometeors produces weaker cold pools. Simulations have shown that too cold and fast-expanding pools inhibit the formation of tornados. The statistical observations suggest that this might be the mechanism by which the weekly modulation in pollution aerosols is causing the weekly cycle in severe convective storms during summer over the eastern United States. Although we focus here on the role of aerosols, they are not a primary atmospheric driver of tornados and hailstorms but rather modulate them in certain conditions. ----- Martin Shough Listen to 'Strange Days... Indeed' - The PodCast At: http://www.virtuallystrange.net/ufo/sdi/program/ These contents above are copyright of the author and UFO UpDates - Toronto. They may not be reproduced without the express permission of both parties and are intended for educational use only.
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