The Gordon Bennett Race 1987 seen from Meterology
The selection of the launch place, Seefeld in Tyrol, had a strong influence for my being dispatched to this race as meteorological supervisor: born in Tyrol, my boss thought, I would know the local winds best. But nevertheless, thanks to all the native people, who supported me with their best “hot tips”.
Collecting weather information was very tricky, for there was no connection to the data base of the meteorological service. All material had to be transported up there from the weather office at the airport by car or a helicopter of the Austrian Automobile Club. For the latest update, I had to collect actual information from mountain stations and weather balloons from my colleagues at Innsbruck by phone. Thanks to all. The Central Office for Meteorology and Geodynamic calculated trajectories (movements of an air mass), based on a network model of the EZMW (European Centre for Medium Term Weather Forecast) out of Seefeld in different altitudes, which were handed out to the teams.
The weather-situation at the weekend of October 3rd or 4th, 1987, promised to become interesting: While the lower layers of the atmosphere (up to about 6000 ft ASL) were ruled by a moderate, but north of the Alps quite fast stream of air from south-south-east. The layers above 10.000 ft were dominated by a short term wedge which crossed the Alps at that time with a streaming from the north-west. So basically, for balloonists there were two possibilities to make long flights out of Seefeld:
- By using the wind from the south in the lower altitude, to slip to the Bavarian foothills of the Alps through the mountains of the Karwendel, then to hope there to stay clear of the ADIZ (prohibited area along the “Iron Curtain”), to enter a fast ground wind from the southeast over the Bavarian Forest, or
- To climb quickly to about 12.000 ft ASL (which means to loose the possibility of a low flight later) and to fly there toward Yugoslavia with the wind from the north-west.
My duty as meteorological supervisor was, to calculate the possibilities of these two opportunities, check them for their risks and to supply the teams with a realistic base for their planning.
The synoptic situation on the day of the launch (October 3rd.): A flat low on the ground above France creates at its front a streaming from the south-south-east, which reaches up to 15 – 20 knots ground wind above the easterly foothills of the Alps. At medium altitudes (700 hPa) is a wedge over the westerly Alps, creating a moderate streaming from the north-west at its front side. The situation becomes complicated by a small, closed low in the altitude above the easterly Alps, leading to more clouds in the AC and SC level and even creating some rain in the area of Salzburg.
Though the race would be done under visual meteorological conditions, I was sure, that the competitors would not cross these particular multiple layers of clouds.
On the afternoon of the launch day, tension rose to a summit, unexpected and unwished in this kind of event. The coverage of clouds grew and their base started to sink down to 6000 ft ASL, while the south wind was too weak in the lower layers, to assure a flight through the Karwendel mountains to the foothills of the Alps. The nervousness of the teams met my own one, and for quite some time, my promises that the clouds would reduce, did not sound very convincing anymore.
At about 5 p.m. my own tests with pi-balls showed the first positive results. The streaming from the south was now strong enough, to guide the balloons gently but determined through the main valley in the direction of Scharnitz/Munich; there, after a short calm, the streaming from the south-east would become vivid and (hopefully), before reaching the prohibited borders to Czechoslovakia and the German Democratic Republic, would lead to areas of no problems. The Ac/Sc clouds however proved to be very hardy and did not start to disappear until one hour prior to launch (9 p.m. local). As soon as the first stars could be seen in the sky, the mood among the teams obviously rose, and most of the competitors decided, to climb quick to use the northwest component of the wind, even if this would mean a crossing of the Hohe Tauern mountains (3.800 meters!).
The results confirm the decisions made: The streaming from the northwest proved to be fast and brought the winner close to the border of Albania, this met the calculated trajectories quite well.
Finally I want to say, that I did not want to miss the experience of this race, for especially among balloonists, you find the most critical, but also best informed customers of the weather service.
After meteorologist Dr. Herbert Pümpel, praised by all competitors, now a German pilot, Thomas Fink from Nürnberg shall tell his story. Together with his friend from the balloon club of Augsburg, Erich Märkl, he flew to the best result of a German team since 1928, which was rank three.Return to 31st Coupe Aéronautique Gordon Bennett