The Origin Of The Term "thermal Wind"

[knocker]

The first outstanding impact of meteorology on military operations in the war arose from the bombing of east coast towns by Zeppelins in the spring of 1915. In those days there was no observation of upper winds in, or above, a cloud layer, and very little on other occasions. The only effective guide to the upper wind was the geostrophic wind (gradient wind as it was then called). It was obvious from the synoptic charts, even reduced as they were, that the Zeppelins had been carried north and east of their target, London, by a SW geostrophic wind of which they had no knowledge prior to, or during, their passage across the North Sea. When the Director of the Met. Office, Dr. Shaw, brought this to the attention of the appropriate authorities, they began to think more seriously of meteorology as a factor in war.

But frequent Zeppelin raids continued over Britain and France, generally they flew too high for the British planes but not always, and as the war progressed by 1916 the planes were armed with explosives and incendiary bullets and this mixture proved deadly to the airships. To get around this problem a third generation of airships, the “height climbers†were built and capable of reaching an altitude of 20, 000 feet.

Using eleven of these new Zeppelins the Germans carried out a carefully planned raid against the industrial cities of northern England on October 19^th, 1917. It proved to be a disaster. One Zeppelin dropped its bombs over London, four were blown off course by a sixty-mile-an- hour gale and ended up over German occupied France, One was shot down by French anti-aircraft fire at 19, 000 ft, one crash landed, one fell intact into French hands and one disappeared without trace over the Mediterranean.

Failure to understand meteorological conditions is the key to this disaster. They failed to allow for the effect of a warm air mass to the west in turning a weak southerly wind at low levels into a strong northerly wind at very great heights. This led E. Gold, D.S.O., F.R.S., who was appointed meteorologist on the staff of the Field Service for France at the beginning of the war, to originate the term “thermal windâ€.

I got there in the end.

Edited September 18, 2010 by weather ship

[johnholmes]

nice explanation there Fred-you may now be asked to give more information what is meant by the term 'thermal wind' and possibly thickness as well!

I tend to duck these issues and use the excellent web site, partly set up Martin Rowley who I knew when forecasting, the link now that Martin has handed over his excellent data set to uk.sci.weather, is below

Just about every question about weather, forecasting etc is in there somewhere, including a first class glossary.

http://weatherfaqs.org.uk/

Edited September 18, 2010 by johnholmes