Workshop Meteorological Panel 25 - 27 September 2009 Pfaffstaetten near Vienna, Austria

PRESENTATIONS Saturday 26th

• Use of the Java TopTask Weather Browser
  Olivier Liechti (Switzerland)
  TopTask is an interactive Java based web application embedded in pc-met. It displays the Top-Therm forecasts for the actual and next day of potential flight distance (PFD) in Europe and some regions in the USA. The forecasts are based on the model chain of DWD, for Europe COSMO-EU and COSMO-DE forecasts are used, for other regions the global model GME is used. PFD's can interactively be selected for different glider classes. The forecast data can be archived for later analysis. In addition, this tool allows for the task planning based on PDF's and post-analysis of the flight after importing the IGC files. It also supports direct export/import into SeeYou.
  Presentation PDF (2 Mbyte)

• Improving Atmospheric Numerical Models using Meteorological and GliderFlight Recorded Data
  Edward Hindman (USA)
  In order to improve the forecast quality of TopTask for the USA, the forecasts of the Colorado State University RAMS model are used. However incorrect temperature and dew-point predictions caused unreliable PDF forecasts. In the course of 2008 several improvements related to the incoming solar radiation and soil moisture were conducted to RAMS. Comparison of the forecast with RAMS and with the DWD global model GME showed good agreement, but still some improvements of surface dew point predictions are necessary.
  Presentation PDF (1.2 Mbyte)

• Convective Structures in Clear-Air Echoes seen by a Weather Radar
  Martin Hagen (Germany)
  Modern weather radar systems are not only able to observe signals from precipitation, but they also show echoes from the cloud-free boundary layer. These echoes have low reflectivities and are normally not shown in the operational data. During summer time these echoes can be observed within a range of up to 50 km around the radar. The sources for the clear-air echoes can either be Bragg-scatter or insects. Observations by polarimetric weather radar give a strong indication that mainly insects cause clear-air echoes. Since insects act as passive tracers it is possible to visualize convective structures and motions.
  Presentation PDF (2.2 Mbyte)

• Climb Rate - Altitude Correlation from Analysis of IGC Files
  Christof Maul (Germany)
  IGC files form 3 championships are used to correlate climb rate with altitude. In order to access maximum meteorological climb rates only data from the distance flight phase were used, i.e. the pre-departure and the post-finish flight phase was manually removed. It is also necessary to separate circling from straight-climb flight phases. It was found that mean vertical speeds are essential independent of altitude which is in contrast to the accepted theory (e.g. T. Bradbury "Meteorology and Flight"). However a deeper analysis and using a 3rd order polynomial fit to maximum climb rates and then compared to the mean climb rates gave an excellent agreement with Bradbury's theory. A further analysis of the climb-rate data showed that a Gaussian normal distribution can be confirmed.
  Presentation PDF (0.9 Mbyte)

• Identification of Waves in IGC files
  Alfred Ultsch (Germany)
  Application of databionics to IGC files: pilots search for updrafts. The task is to develop an unsupervised classifier for climbs in IGC files and separation of thermals and waves. Based on flights in the Andes a classifier was developed. It is validated for the Alps using a manual analysis by Philip Ohrndorf of 160 flights. This was a cumbersome work since only 10 downloads per day from OLC are allowed.. An accuracy of 76% was achieved with the unsupervised classifier. These flights were used to present a wave climatology for the Alps. It can be assumed that the classifier gives similar accuracy for the Andes. For the Alps also an Artificial Neural Network could be constructed since training data sets are available.
  Presentation PDF (3.8 Mbyte)

• Mountain Waves - DWD's new Tool to Forecast Lee Waves
  Erland Lorenzen (Germany)
  The DWD high resolution model COSMO-DE (2.8 km horizontal resolution) allows the forecast of mountain waves at the German Mittelgebirge (small mountains up to 1500 m MSL). Waves up to 7000 m MSL have been forecasted at the Harz, Thüringer Wald, Schwarzwald and Riesengebirge. The Forecasts are consistent with the cloud structure observed by satellites.
  Presentation PDF (2.4 Mbyte)

• Are Cross-Country Wave-Flights possible almost without Mountains?
  Ralf Thehos (Germany)
  Especially during winter the DWD COSMO-DE model indicates wave structures without any relation to terrain. Wave structures are also sometimes visible in high resolution visible satellite images. Some flights by Ralf and colleagues in the Rhine Valley confirmed the wave structures. It is assumed that the waves are initiated at inversion layers with high wind speeds above.
  Presentation PDF (1.5 Mbyte)

• Stable and Convective wave clouds
  Julian West (Germany)
  Julian presented a number of impressive photos from wave clouds, rotors and morning glory clouds. Their stable and unstable appearance did leave a lot of questions which can not be answered in detail.
  Presentation PDF (0.6 Mbyte)

• Stratified Flows over the Sierras
  Larry Armi (USA)
  Larry presented results from the T-REX campaign (2006) over the Sierra Nevada. Airborne observation with an instrumented King Air within stratified flow showed that only gap flow is able to descent into the Owens Valley. The analysis of flight track and measured 3-dimensional wind was done with Google Earth. An impressive graphical presentation is possible with this new technology. The same kind of analysis was repeated for some flights within Föhn during the MAP campaign in 1999.
  presentation currently not available (paper under review)

• Enhancement of Convection in Arid Areas
  Markus Stracke (Austria)
  In savannah regions convection and thus precipitation can be enhanced by changing the surface properties, i.e. by enhancing the sensible heat flux. The evaporating water from irrigated areas will be recycled if the irrigated areas are surrounded by i.e. black tires.

• Gilding Safari Adventures without Crew
  Thomas Seiler (Germany)
  Thomas presented his experience from some safari flights within the last years. Without a supporting team he managed (in most cases) to fly tours through Germany for several days and to return to the starting point. The challenging goal of such flights is the weather forecast for several days. Each evening an airfield with towing possibility has to be reached.
  Presentation PDF (2.3 Mbyte)

• The Role of Climate Changing on Organisation of Thermals
  Ahmet Tokgözlü (Turkey)
  The authors from Turkey could not come themselves to Pfaffstätten to present their papers, but they did sent a presentation.
  Daily programs of gliding activities are based on convection potential in flight area. Vertical velocity, air temperature, wetness, vegetation cover, daily heating rate, instability condition and heat fluxes have a key role on prediction of flight lengths. The main aim of this study is to analyze temporal and spatial variations of air temperature and rainfall rate and climate changing effects on soaring conditions in Turkey.
  Presentation PDF (1.4 Mbyte)

DISCUSSION Sunday 27th

• The next SAA Convention will be held in Little Rock, Arkansas, USA, January 28-30, 2010.
• The next OSTIV congress will be during the World Gliding Championship in Szeged, Hungary. The dates for the OSTIV event are July 21 - 28, 2010
• The next workshop of the OSTIV Meteorological Panel will be in 2011
• Ward Hindman did announce that the "Technical Soaring" Journal is now available online http://journals.sfu.ca/ts/index.php/ts
• Hermann presented a message from the OSTIV president Loek Boermans. On that occasion Hermann announced that OSTIV will invite us for the dinner Saturday evening. Special Thanks to Loek from all participants!!
• The upcoming European regulations for pilot licences are currently under discussion. To avoid an unnecessary load on meteorological themes for glider pilots, suggestions on the structure of meteorological education have to be suggested to EASA. A working group lead by Ghislaine Facon was established during the workshop and will investigate meteorological themes for glider pilots within the next year.

Summary by Hermann Trimmel and Martin Hagen