XXIX OSTIV Congress

August 6 - 13, 2008

Lüsse, Germany

Papers presented within the Meteorology Session

Nilton Renno Electric Sensor for Searching for Thermals Remotely
Roland Stuff Non-Viscous Vortex Generation due to Buoncy, an example of application of compulsive forces in fluids
Olivier Liechti The phase diagramm of soaring: flight mode transitions in combination of isolated and aligned lift patterns
Olivier Liechti Meteorological predictions of updrafts in aligned patterns
Edward Hindman Status of meteorological system for planing and evaluating glider flights in the northeast USA
Jörg Dumann A report on glider pilot activities to document leewave-events in northern Germany
Zafer Aslan Analysis od Cloud cover and effects on thermalspotential variation
Bahareh Bastanfard Analysis of the structure and dynamics of a surface frontal zone
Laleh Shabrang Analysis of blocking and its effects on cyclogenesis over the Mediterranean
Beda Sigrist Identification of slope wind areas using topografic models
Paper of interest presented in the Technical Session:
Christof Maul Comparative Statistical Analysis of Soaring Competitions
Hannes Ross Fly around the World with a Solar Powered Airplane


Summary of the papers presented within the Meteorology Session

Nilton Renno, USA: Electric Sensor for Searching for Thermals Remotely
The electric field near the surfce in fair weather conditions is of the order of 100-300 V/m around the globe. Thermals carry these charges upwards with the air rising from the surface forming modestly charged updrafts. The fact that thermals are charged allows them to be detected remotely with sensitive electric field sensors. The electric field sensor is so sensitive that it is capable of detecting them more than 1 km away. First measurements of thermals' electric fields with a miniature sensor mounted on the ground and in a Discus-2a sailplane have been done recently.
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Roland Stuff, Germany: Non-Viscous Vortex Generation due to Buoncy, an example of application of compulsive forces in fluids
This very theoretical lecture showed the mathematical background, necessary to calculate vortices. The theory presented is applied to the interference between an aircraft wake and atmospheric instability. In this case a latent atmospheric instability may be triggered off by the aircraft wake. An example was given from a B747 with a significant downdraft calculated.

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Olivier Liechti, Switzerland: The phase diagramm of soaring: flight mode transitions in combination of isolated and aligned lift patterns
In this paper the optimum cross-country speed of a glider is investigated which results from the climb rate when spiraling in isolated lift combined with gliding in patterns of aligned lift of a particular strength. By plotting the climb rate in isolated lift on one axis and the airmass vertical motion in aligned lift on the other axis isotach consists of two sections in terms of flight modes: dolphin and climp mode.The phase diagram of soaring flight modes is useful for flight planning if the climb rates in isolated and aligned lift can be predicted by meteorological models.
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Olivier Liechti, Switzerland: Meteorological predictions of updrafts in aligned patterns
In the second paper Olivier presented how to predict this combination of thermals and dynmic lifts. He used his well developed Top Task Competition tool and extende it to this kind od of aligned updrafts. With this extension the simulated ground speed has improved significantly for flights he evaluated in some examples.
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Edward Hindman, USA: Status of meteorological system for planing and evaluating glider flights in the northeast USA
Most gliders are equipped with GPS-flight recorders which store the position (x, y, z) as frequently as every 2-seconds. Further, the sinking speed of the glider as a function of forward speed is well-known. Consequently, these machines can be atmospheric probes; they can identify and measure regions of rising, sinking and horizontally moving air. Conversely, given predictions of the regions from a meso-scale numerical weather-prediction model, the glider can be 'flown' through the regions to predict the feasibility of a flight. Then, following the flight, the flight-recorder data can be compared with the predicted flight to help evaluate the weather predictions. Accordingly, a meteorological system consisting of the Regional Atmospheric Modeling System (RAMS) coupled with the glider flight algorithm TopTask Competition (TTC) was developed for Colorado USA and shown to be successful in predicting long-distance glider flights. Additionally, this study is a first-step toward an on-line glider pilot self-briefing system for the NE USA.

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Jörg Dumann, Germany: A report on glider pilot activities to document leewave-events in northern Germany
Detailed studies about waves have been made especially in the area around the Harz, an isolated mountain in northern Germany. A special forecasting system motivates the pilots to use all promising conditions for wave flights. Every wave flight is recorded and available on the internet with additional comments of the pilots. This exchange of the experiences allows a better understanding of special phenomenas..To gather more detailled meteorological information during the wave-flights a special logger were developed with several digital and analog ports available. Up to now we acquire temperature-, static pressure-, g-acceleration-data besides the postion. Fortunately the logger is a product of a radio amateur volunteer group. The complete kit of the logger-system costs around 100,-- Eur. Every year tehre is a meeting to discuss the pheomenas and to exchange expiriences between pilots and scientists.
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Zafer Aslan, Turkey: Analysis od Cloud cover and effects on thermals potential variation
The main aim of this paper is to analyse the climatologic variation effects on cloud cover and its role on thermal potential in selected areas in Turkey. It is reported that positive anomalies of North Atlantic Oscillations (NAO) resulted in decreasing trend of precipitation values in Eastern Mediterranean Area. Negative NAO anomalies accompanied by increasing precipitation values in and near vicinity of Turkey. To define the role of large scale effects like El Nino, La Nina and NAO, Wavelet Tools have been applied on different variables in recent years. This study covers 1D Wavelet packets and continuous wavelets on historical cloud cover values in North western and central parts of Turkey. Outputs of wavelet applications explain tele -connections between NAO and cloud cover variations and the role of this variation on thermal on the other word soaring potential of study area.
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Bahareh Bastanfard, Iran: Analysis of the structure and dynamics of a surface frontal zone
For the first time we had a speaker from Iran. Bahareh is a student from Teheran and it was not easy for her to come to Lüsse. She presented a synoptic view of the detailled structure of a coldfront. Physical parameters in connection with different cases of fronts were shown. Also interesting frontogenetic and frontolytic effects were considered. She was accompanied by her friend, also a student Laleh.
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Laleh Shabrang, Iran: Analysis of blocking and its effects on cyclogenesis over the Mediterranean
Laleh presented her studies about the processes of upper low developments over Mediterranean Sea. Interesting to hear, that this cyclones also have a significnt influence so far to Teheran. A distinction of different synoptic features in connection with blocking effects were made. Besides the impressive and very good presentations it is interesting, that this two students found the Ostiv via Internet and did not know anything about gliding before. Triggered by the exchange of ideas, now they are thinking about to finish her studies somewhere in Europe.
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Beda Sigrist, Switzerland: Identification of slope wind areas using topografic models
Beda was the last speaker of the day and the congress. He is the winner of the Ostiv-Diploma for his paper he presented 2006 in Eskilstuna. Based on the ideas of "TherMap"which indicates the "hot spots of updrafts in mountain ares he developed now a "WindMap". The goal is to find out the best places for slope soaring conditions taking into account different wind directions. He uses high resolution models of the orography and defined windfields. His results are in excellent agreement which was experienced by pilots during flights. In the next step he will try to get the windfield from model output and then he will get a very promising tool of "Slope wind forecasts".
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Paper of interest presented in the Technical Session:

Christof Maul, Germany: Comparative Statistical Analysis of Soaring Competitions

Satellite aided navigation in cross-country soaring provides a huge set of data which can be employed in order to characterize meteorological conditions or pilots' tactical decision making. A systematic statistical analysis of flight log data of the Lilienthal Glide 2007 at Lüsse, Germany, the European Gliding Championships (EGC07) at Issoudun, France, and the Junior World Gliding Championships (JWGC07) at Rieti, Italy, is presented. Flight log data are analyzed in order to extract vertical speed distributions and altitude distributions in space and time. The data allow to assess the role of climb in thermals and climb in straight flight.
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Hannes Ross, Germany: Fly around the World with a Solar Powered Airplane
Quite a few manned and unmanned solar powered aircraft have been developed and flown in the last 30 years. Objectives and missions cover a wide spectrum ranging from a pure technological goal to "Fly with Solar Energy" to civil or military surveillance and reconnaissance missions. However, none of those aircraft was able to demonstrate a continuous day and night operation until 2005. Development aspects of the Solar Impulse Program are described and a program status is provided.
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