At 09:17 12 November 2015, krasw wrote:
On Wednesday, 11 November 2015 15:18:02 UTC+2, danlj wrote:
I am researching shear wave and thermal wave.
=20
For example, the WI glider altitude record was set by Ted Clausing in
the=
rmal wave.
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For example, on 4/24/98, bases were 7000 msl, thermal wave took gliders
t=
o 16-20,000 msl over lower Michigan, and stacked lenticulars were seen.
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If you understand how to predict where shear and thermal wave will
occur,=
I'd be delighted to hear about that!
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In any case, if you'll send me dates/locations of thermal-wave flights,
a=
nd altitudes achieved, and a bit of story about the conditions, this
would
=
be wonderful. Attaching a log file would be a bonus.
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Send to: dleroyj AT gmail.com
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Thanks!
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DrDan

Thermal waves are pretty well researched subject in meteorology. I did a
sh=
ort paper of thermal waves ages ago and still have a box full of printed
ar=
ticles. Well known glider pilot-meteorologists such as Joachim Kuettner
and=
Tom Bradbury are good starting point for search. They observed thermal
wav=
es in 60's and 70's. There was at least one big measurement campaign in
US
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during 80's or 90's. They flew fully instrumented plane several times
over
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convective boundary layer and reported widespread wave occurrence. Model
st=
udies followed.


We have a bit of an advantage in the UK in that cloud flying is permitted
and that makes it a lot easier to get into thermal wave. I've done quite a
lot of it over the last 45 years. I've also discussed it with both Joachim
and Tom. My experience is that very weak (reduced sink usually) wave,
close the the up-wind side of the cumulus top, is there more often than
not. It might even be more accurate to call this "cumulus ridge lift".
Classic streets with upper wind, immediately above the inversion, at a
significant angle to this (doesn't have to be 90 degrees, 60 or so will
do), producing good usable wave (best I've ever seen was about 8 knots), is
quite rare in the UK but I've experienced a fair number over the years.