Workshop

22 - 24 November 2002

Neresheim, Germany

14 Representatives from Austria(2), Germany(7), France(2), Slovenia (1) and Switzerland (2) took part in this meeting.

After opening the workshop, the Chairman of the Sailplane Development Panel Dr. Michael Rehmet was invited as a guest to give a short overview of the topical subjects of their working group; especially of the last meeting in Tehachapi/USA.

Program
Friday 19:00 - 21:30 Opening, Introduction of the participants,
Collecting items for the program
Saturday 09:00 - 12:30
14:00 - 18:30
20:00 - 22:00
Mountain wave forecasts
Convection models
Working groups
Sunday 09:00 - 14:00 Handbuch, homepage, future events
Closing lunch

Content

  1. Forecasts for Gliding

  2. 1.1. Waves
    1.2. Convection
  3. Handbuch
  4. Internet-Homepage
  5. Future events
  6. Any other business

 

1. Forecasts for Gliding

1.1 Waves

Ghislaine started with her lecture on "Dynamic Experiments in the Pyrenees" and summarized the results from the previous experiments Colombe (1967-70), Pyrex (1990) and Map (1999).

In the second part, an original study of the cross country flights between 1982 and 2002 gave the result: the real flights are quite in agreement with the previous meteorological experiences made by P.Porcheron in 1970 and A.Blanchard in 1990.

Because there is a great interest for dynamic phenomena from scientists as well as from pilots, we conclude: a good cooperation in experiments will improve our knowledge of this meso-scale phenomena.

And from the technical point of view the time is ready now: we have high performance gliders and precise data-loggers - they have only to be adapted to the scientific needs.

This excellent presentation about this meteorological phenomena encouraged everybody to contribute their results and ideas to this subject very openly.

Erland informed us about PC-Met/DWD, where cross-sections over the Alps give a good picture of wave positions.

Rene explained his wave forecasts, available on his homepage (www.mountain-wave-project.de). There you also can find a guestbook for verification.

Olivier and Jon started the discussion: What techniques do we have to forecast mountain waves and finally how should the forecast be presented to pilots?

Even the fine mesh models ( e.g. BRD/LM ) are not able to forecast all the details of waves pilots want to have. An alternative approach would be a statistical correlation between different wind directions and lift rates in different mountain-areas, e.g. the alptherm-regions. Or a spectral consideration, the correlation between the mountain sizes/shapes and the wavelengths at certain wind-speeds. A more practical approach would be to evaluate logger-data from wave-flights and work out some statistics in respect of the synoptic situation for different mountains.

Finally everybody agreed that all of these proposed methods could improve the forecast techniques and perhaps converge in the future.

Pilots requirements: wind direction, position and intensity of waves, foehn-cloud gaps

The required top of the mountain wave forecasts is Fl 240.

Referring to the presentation of mountain waves for pilots, the present status of symbols used, published in the documents or used in practice is as follows:
ICAO-Annex 3 - Meteorological Services for International Air Navigation, Symbols for significant weather, APP 1-16; Edition 1/11/01 Mountain waves
WMO Technical Note 158, Handbook of meteorological forecasting Chapter 7, Presentation of soaring forecasts, 7.2.2.2 Documentation
Austrian weather service, Alpfor
Waves with winddirection

The group suggests the following symbols:

Weak waves less than 1.75 m/s average updraft

Moderate waves 1.75 - 3 m/s average updraft

Strong waves more than 3,0 m/s average updraft

Additional arrows for the wind-direction
Example: weak wave with northwesterly wind

Remark:

Foehn-cloud gaps are nowadays not possible to forecast precisely, the grid-resolution of models is still too big. But nevertheless it is of vital importance for wave soaring that the best guessed nebulosity of wave clouds at different altitudes (derived from humidity of models) be presented to pilots along with wave strength, since 0 octas of rotors/lenties means more difficult "cheminements", like blue thermals, and 8 octas means that flights will be impossible, even if a strong wave is present.

Finally Rene presented the latest information on the in the Mountain Wave Project:

1.2 Convection

Inspired by the Ostiv-paper from Erland and Olivier presented at the XXV OSTIV Congress in St.Auban about convection analysis for the Sahara/Tamanrasset, Denis managed to fly three seasons in Morocco. His exciting experiences and impressions motivated the audience not only to fly there but also to get a better understanding about extraordinary convection schemes (cloud base 5-6000m), convergence lines along Atlas and Anti-Atlas and something like convergence-waves (?).

At the end of May, beginning of June he did a lot of flights over 1000km, the highlights being a 1250km triangle with 140km/h and a maximum distance of 1300km.

Picture about Morocco: http://volavoile.ouarzazate.free.fr/eldorado/

So perhaps sometime we can test in that area the "Toptask", presented afterwards by Olivier and Erland. This new flight planning tool is a means of combining the Top/Alptherm output with the performance of any glider, thus giving precise information about the distances you can fly. It will be tested next year in Germany and pilots should enjoy this sophisticated "game".

Following his experiencies with the Alptherm, Olivier adjusted the convection model according to:

The last speaker on this subject, Andreas, presented the evaluation of the quality of the Alptherm forecast in Austria, prepared by Austro-Control:

200-1000 requests per day is a significant sign of acceptance of this product and exceeded all expectations.

Also the feedback from the pilots about the different forecast parameters ( wind, convection-height, thermals etc ) showed a clear bias to good and excellent.

 

2. Handbuch, German version

Status quo:

Rene found the original version of the text-file and unfortunately Jon did the same job independently. Nevertheless we do have now two word-versions, which should be very similar. Holger put all the graphics into 300dpi jpg and gif files.

Next steps:

Erland gets all the existing files. After checking by Erland the volunteers:

Hermann -Allgemeiner Teil, Olivier-Thermik, Rene-Wellen, Wolf-Dieter-Thermikwellen

will get their chapters to review (only with minor changes) them and to send it back to Erland as soon as possible.

Erland will contact Rene and Jon for support on improements for the Internet-version (colour-pictures etc. ). Either our webmaster Martin will integrate the Handbuch in the Internet or Rene and Jon will do it directly if they will get direct fdp-access to the DLR- server.

Our homepage will be the only way of publishing this manual; no paper version is planned.

At present the DWD is not able to be a publisher.

For the regular update of parts or chapters of the handbook, an editors-commission (Erland, Rene, Hermann & Jon) is set up, who decide about the handed in changes. In this way, a regular update apart from OSTIV-meetings is guaranteed and the independence of commercial interests is warranted.

A new international version is planned - an internet-translation-program may help the authors in translating their chapters.

 

3. Internet-homepage www.pa.op.dlr.de/ostiv

Martin informed the group by letter about our homepage:

Statistics: On average about 200 hits per month.

Guestbook: Pilots have to be encouraged to use this new discussion platform to ask questions and discuss meteorological matters.

So please look at this page from time to time and give your comments or answers.

Remark: Perhaps "Forum" would be better than "guestbook" ?

Links: Whenever you find a good link for our homepage please inform Martin so that he can add it !

Collected during our meeting:

www.wolkenatlas.de
volavoile.ouarzazate.free.fr

If you have something new about OSTIV activities or projects, please feed with this information our webmaster Martin and he will update our homepage!

 

4 Events 2003

4.1. Training- Seminar

Where and when?

Airfield Jaca, south-side of the Pyrenees

Information from Ghislaine:

"I had a discussion with the director of Jaca about our meeting there from 30th March to 13th April 2003 who said:

"I have the pleasure to give you the confirmation that it is possible, and that the team of Jaca will be happy to receive you.

On site, Duo Discus can be used for measuring!

To organise our stay best in Jaca it would help if you register early."

Up to now Wolf-Dieter, Thomas, Holger, Erland, Hermann, Christof and Rene showed their interest to come.

If you want to participate please send the name of pilot(s), glider and the dates wanted to Hermann.

More about the airfield: http://jaca.com/aerodromo/

4.2. XXVIII. OSTIV-Congress

Where? Leszno, Poland

When? most probably 25.7.-2.8. 2003 and Scientific session: 31 July and 1 August.

Everybody is invited to motivate him/herself or somebody else to present a paper.

4.3. Next Workshop

When ? 21.- 23. November 2003

Where? Thomas suggested Bremen, Lufthansaschule;

So I hope to see you at this place in one year again...

 

5. Ony other business

Christof reported on the evaluation of flight data from loggers as a basis for a "thermal map".

See: http://www.pfg.dk/termikanalyse/ and http://www.regnoc.com/hotspot/

His second information was about the possibility of vertical soundings with GPS- controlled microaircrafts, built by the Institut für Luft-und Raumfahrtsysteme.

  Books of interest
Les Pyrenees en Planeur

1994

Alain Blanchard Editions Odyssee, Route de Lavaur 81304 Graulhet Cedex

ISBN: 2-9507497-1-2

Vol.a.voile.pyrenees@wanadoo.fr

The Path of Soaring Flight

1998

Frank Irving Imperial College Press 203 Electrical Engineering Building London SW7 2BT ISBN 1-86094-055-2
Atmospheric Processes over Complex Terrain

1990

William Blumen et al. AMS, 45 Beacon Street, boston, Massachusetts 02108

ISBN 1-878220-01-2

An Album of Fluid Motions

1997

Milton Van Dyke The Parabolic Press PO Box 3032, Stanford California 94305-0030

ISBN: 0-915760-02-9

Gravity Currents

1997

John E Simpson Cambridge University Press

www.cup.cam.ac.uk

ISBN 0 521 66401 2

Fundamentals of Fluid Mechanics

2002

Bruce R. Munson et al. www.wiley.com/college/munson

ISBN 0-471-44250-X

Introduction to Micrometeorology

1998

S. Pal Arya www.academicpress.com

ISBN 0-12-059354-8

Meteorology for Scientists and Engineers

2000

Roland B. Stull www.brookscole.com

ISBN 0-534-37214-7

Multi Media Fluid Mechanics CD Cambridge University Press

ISBN 0-521-78748-3