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Pete Ware · November 13th 04, 05:02 PM posted to sci.geo.meteorology

On 2004-11-12 13:38:00 -0500, (Brian Salt) said:

I'm researching a WWII airfield near where I live in Devon, U.K.

It appears that the meteorologists used balloons as part of the data
collection, but at that time they had no radar, etc., to help with
finding the height of the balloon.

The control tower of this airfield was equipped with two pillars to
which theodolites could be attached/mounted. Apparently, these were
used to determine the angle of ascent and the height of the balloon.

Does anyone have any idea how that could be done, given (as far as I
can see) that you need the horizontal distance to the balloon as well
as the angle to find the height? Or would the use of two theodolites
simultaneously, spaced at about 22 feet apart, allow the height to be
found without needing the horizontal distance?

TIA.

Brian Salt.
Remove NS from address before replying.

The two pillars probably just meant they had two theodolites.

The method used is based an an assumed rate of ascent. Fill the balloon
with the correct amount of hydrogen or helium, and it would rise at a
calculated rate. Copy down the azimuth and elevation at timed
intervals, then use calculations & now a computer to come up with the
wind direction and speed. I did it all the time as a weather observer.
Just part of the job.

Pete