Meteorological Reconnaissance A Brief Introduction (Part 1)
I have learned to my horror at our social functions that many (most?) of our members are very vague about 202's raison d'etre pre Search and Rescue. While I know little about the early Coastal Command work, I can help on Meteorological Reconnaissance. This note gathers together, from many sources, including The Met Office Library, John Malcolm and personal memory, the story of Meteorological reconnaissance in the Royal Air Force from the early days of World War 2 till the mid sixties particularly as practised on our Squadron. It does not pretend to be a precise history; it is only information and entertainment for our younger members. Perhaps someone will have to do the same some day for Search and Rescue!
Meteorological Reconnaissance Pre 202 Squadron
Even now with the advent of remote sensing systems like artificial satellites, the main method of finding out about the weather over the oceans is still to persuade merchant ships on passage to observe and report the weather every six hours. Sixty-odd years ago there was nothing else
With the outbreak of the Second World War, ships in the North Atlantic could no longer report their positions and weather and the Atlantic became what is known in the jargon as a "data sparse area". As an aside, the rate of attrition of merchant ships in wartime is demonstrated by the size of the British Voluntary Observing Fleet: the 995 British ships reporting weather in 1939 had been reduced to 480 when peacetime reporting restarted in 1945. The target number in 1945 for a reasonable network of ocean observations was 1000 British ships.
Knowledge of the weather, particularly predicted weather, is essential to the prosecution of modern (1900s onwards) warfare and those countries who had weather data during the war classified them SECRET. Other sources of information had to be found. One method used was long range aerial reconnaissance and, in Britain, the bulk of the task fell to Coastal Command.The use of aircraft for sounding the atmosphere over a spot from ground level to their ceiling began in the 1914-1918 war, mainly as an aid to artillery work, and had been routine since 1925; these provided early examples of the acronym - "THUM" from "Thermal Upper-Air Measurement" and "PRATA" from "Pressure and Temperature Sounding". (Nowadays we would have used the letter "S"). One such sounding was made at Worcester using Spitfires for many years until well after the war.
Long range reconnaissance, the kind done later by 202, began in Spring 1941 with three Met Flights, 1403, 1404 and 1405 , being established at Bircham Newton, St Eval and Aldergrove respectively to fly Blenheims. Soon afterwards 1407 Met Flight was formed to operate out of Reykjavik.1406 Met Flight was formed at Wick and absorbed 1408 Met Flight. These, however, were PRATA flights using Spitfire 2s. Flights were also formed to operate out of Tiree and Gibraltar. The image on the right "Tracks"shows the network of long range meteorological reconnaissance flights available in the latter part of the war, by which time some thirty flights a day were being made. There were also flights operated by the United States Army Air Force (and possibly Navy?) from Burtonwood, Newfoundland, Bermuda and the Azores. The principal Squadron involved was the 652nd Bomber Squadron of the 25th Special Reconnaissance Group operating Flying Fortresses. 269 Squadron RAF also operated out of Lagens from 1944.Initially these Flights were equipped with Blenheims, but soon progressed through Hampdens to Hudsons allowing them to progress towards truly long range work.
In 1943 Halifax and Ventura aircraft were approved for long and medium range reconnaissance and new squadrons, 517, 518, 519, 520 and 521, were formed or or moved into the reconnaissance field subsuming the earlier Flights. Brawdy, Tiree and Langham were added to the stations operating Met Flights.You will believe that the above is actually a drastic simplification of the formations, amalgamations and moves that took place then and the re-equipping was nothing like as simple as I suggest with each Command and Squadron claiming higher priority for available aircraft.
Two operational successes other than weather watching were recorded about this time: In April 1941 Flt Lt Douglas Bisgood was nearing the end of a RHOMBUS (fig1) sortie when he came across three Junkers 88 returning to Germany from a raid over England. Bisgood, a former fighter pilot, gave chase and one of them was shot down with the Blenheim's forward firing gun. He was awarded the DFC (or probably a Bar).
On 12 August 1942 the EPICURE (fig 1) flight from St Eval (Flt Lt Dennis Wykeham-Martin) spotted a u-boat on the surface and attacked. The boat crash dived, but was blown out of the water by two anti submarine bombs and sunk. The crew were commended by AOC 19 Group.
An indication of the spirit on those early Met Flights (and an inkling of what it must have been like to be Flight Commander) comes from the No 1403 Flight Line Book: "If the cloud base is more than 10 feet, a Blenheim can land because it is only 9 feet high". Initially the weather observing on RAF flights was done by the Navigator - a class of men that I have long regarded as the brains of the RAF. The decision to create a Meteorological Observer Section of the General Duties Branch of the RAF(VR) was promulgated late in 1942 and sufficient volunteers rapidly came from the mostly civilian Meteorological Office. Training began early in 1943. By the end of the war 20 RAF officers and 80 NCOs had been trained in addition to a number for the USAF. In addition to weather observing, training included navigation and air gunnery; in fact the first observers wore the AG Brevet. They didn't hang about in those days: from basic training to operational was not much over two months!
Sorties varied from day to day to suit operational requirements, but a typical triangular flight would be two low level legs with one high level one. The first, outward leg, would be about 700 nautical miles in length and would be flown at a pressure height of 950 millibars. This was achieved by the Met Observer using his barometer to talk the pilot onto that height and then the remainder of the leg was flown on the altimeter with no alterations to the sub-scale. If the mean sea level pressure made 950 MB an unwise height, 930 or even 920 could be used. Weather observations were made every 50 NM with a descent to 50 feet asl at every fourth position to measure the sea level pressure. On these "sea level" runs the height was estimated by the pilot. Enough said, though radio altimeters did come along later!
In addition to the barometer, the Met Observer had two main instruments: the psychrometer and the air speed indicator. This latter was essential to apply corrections for the effect of air friction to the temperature readings. The psychrometer was an aviation version of the familiar dry and wet bulb set and was mounted on a strut outside a window close to the observer with water being supplied to the wet bulb by pumping from a tank inside the aircraft.
Another example of the spirit (or something) prevailing in those days happened at Gibraltar when the Halifaxes were being modified and were not available for Met use and the Met Air Observers (as they were then called) flew with 202 Squadron on Catalinas. There was no provision to mount the external psychrometer strut and the temperatures were obtained by the MAO strapping the psychrometer to his arm and leaning out of a hatch for some minutes until the thermometers settled down and could be read accurately. At the end of the low level leg a climb was made from 50 feet to 500 MB with temperature measurements being made every 50 MB. More details of this procedure will appear in part 2 of this article.The return, low level leg was a near mirror image of the outward one.
Part two of this story, will cover Meteorological Reconnaissance after 1945 by No 202 Squadron, the Cold War and other 202 Squadron matters.
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