buttman wrote in
:

On Jul 23, 12:47*pm, Mxsmanic wrote:
buttman writes:
Theres a little "eye" that looks up at the sky at various points.
It detects if there is cloud, or sky. The sensor is prone to
errors, though. Sometimes if it's broken, it'll say its overcast
because some of the sensors are pointing diagonally and are sensing
the side of the cloud. I had an ATC college-style text book that
had a very informative diagram of how they worked, but that book is
long gone.

http://www.cyanogen.com/products/cloud_main.htm

here is an example of one.

Cool--I wouldn't mind having one (useful for photography as well as
astro
nomy
and aviation). *However, it's still a ground-based sensor, so it
would
only
see the first level of clouds. *Conversely, a satellite would only
see
the top
layer of clouds. *If there are three or four layers of clouds, how do
w
eather
services discover them?

The same is true for temperature, humidity, and pressure. *Pressure
you
can
probably infer from surface pressure, and temperature you can guess
at in
a
similar way. *Humidity is more vague. *I'm curious as to how all of t
hese get
measured aloft.

And what about winds? *Weather services seem to have awareness of
winds
aloft,
but where are they getting the measurements? *Winds aloft may have no
correlation with surface winds and can change a lot over short
distances.
*You
could set up probes, but that's a lot of probes to launch and recover
eve
n to
cover small areas. *You could rely on PIREPs, but that seems kind of
hi
t and
miss. *So how is it really done?

How are the paths and speeds of jet streams determined?

When I was in college I took a meteorology class which was taught by a
grad student who spent the last summer doing an internship at a
weather station. She worked with the people who did the Upper Air
Charts. She said they release balloons at least every day, which is
how they get their measurements. From there they use the data to make
forecasts.

As far as in-between could layers, its only reported by pireps.

Nope, wrong again, fjukktard.

Not that it matters, since your "student" will never ever fly.


Bertie