XXIX OSTIV CongressAugust 6 - 13, 2008Lüsse, Germany |
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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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