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Moon and Weather
Name: Donald C.
Status: other
Age: 60s
Location: N/A
Country: N/A
Date: 10/16/2004
Question:
Does the moons phase affect the weather? Are there
atmospheric tides as with the seas? If so how would pressure be affected?
Replies:
The effect of the moon on weather is indirect in that the moon affects
ocean tides that can alter ocean currents that can affect weather. To your
second question, yes also, the gravitational pull of the moon does produce
atmospheric "tides"; however, the effect, while measurable is small and
overwhelmed by other atmospheric factors. Another effect, that while known
and measured for several decades at least, has recently begun to receive
more attention by geologists is the tidal effect of land masses. In
particular new satellites that can measure the topology of the earth show
unmistakable "ups and downs" due to the gravitational pull of the moon. It
has been hypothesized that these small shifts might be correlated with
earthquakes and/or volcanic activity.
Vince Calder
Donald,
The atmosphere, being a fluid, is affected by the moon,
resulting in an Atmospheric Tide, a wave that propagates
through the atmosphere. However, the increase in
atmospheric pressure that occurs at the front edge of
the wave is so slight that it is hard to detect from
the myriad of other waves that are always present in
the atmosphere.
David R. Cook
Atmospheric Research Section
Environmental Research Division
Argonne National Laboratory
Dear Donald-
The moon has no statistical effect on the weather...there is a minute
effect on atmospheric pressure.
"Tides are raised in the earth's solid crust and atmosphere as well as in
the oceans. Every body in the universe has some tidal effect, however small,
on every other body. This effect is directly proportional to the mass of the
body causing the tide but inversely proportional to the cube of the distance
between the bodies. The earth's nearby moon is about 2.17 times as effective
as the more massive sun in raising tides on the earth, even though the sun
exerts a much greater total force on the earth than does the moon. Thus, the
moon's proximity explains its dominant role in creating tides." See this
link for more details...
http://www.infoplease.com/ce6/sci/A0861550.html
There are atmospheric "tides" but they are mainly due to heating of the
upper atmosphere by the sun. They cause a diunral pressure variation, with
the maxima around 10 a.m. and 10 p.m. each day, with minima around 4 a.m.
and 4 p.m.
Here is a link explaining this phenomena...
http://www-das.uwyo.edu/~geerts/cwx/notes/chap01/diurnal.html
And here is an interesting fact...atmospheric tides were a factor in the
period of rotation of the planet Venus, which has a much denser atmosphere
than the Earth. Here is a link to further explain that...
http://www.imcce.fr/Equipes/ASD/Venus/venus1_en.html
Wendell Bechtold, meteorologist
Forecaster, National Weather Service
Weather Forecast Office, St. Louis, MO
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Update: June 2012
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