What has triggered the idea behind
Many birds find their
best updrafts using inbuilt rules honed over millions of years of
evolution. Compared to this, statistical maps based on actual flight
tracks tend to show thermal hotspots along "trodden paths",
typically in the vicinity of gliding airfields, usually neglecting
basic conditions such as the time of the year or the daytime. On the
other hand physical models permitting to identify thermal hotspots
considering these basic conditions are bound to be very complex and
require a lot of computer power to simulate results.
Our idea was therefore to try a
computerized model using simple empirical rules derived from descriptions
of experienced pilots, and to then validate and refine them by comparing
the results with actual glider flight logs available on OLC. After
about two years of trial and error research, the computed thermal
maps started to become more and more realistic and to arouse the attention
of renown glider pilots and meteorologists of OSTIV. Their encouragement
finally led to the publication of the the model in the OSTIV Journal.
On the occasion of the opening of the Gliding
World Championships 2008 at Lüsse/Berlin, Germany, OSTIV
considered TherMap to be " a quantum leap in analyzing and optimizing
flight paths in known and unknown orographies".
Who is behind TherMap ?
In 2004 Beda Sigrist, a senior Swiss glider pilot with a background
in computer modelling, was intrigued by the fact that the vast knowledge
of experienced pilots had never been translated into a computer model
permitting to show the thermal hotspots on a map. Impressed by the
precision of the regional meteorological forecasting tools of RegTherm
and TopTherm, he started to investigate the possibilities of making
use of presently available topographic data. With the help of descriptions,
particularly of Jochen von Kalckreuth, the primary advice of
Olivier Liechti (Initiator of Regtherm and Toptherm), the encouragement
of OSTIV, particularly of Hermann Trimmel, as well as the positive
response of many other experienced glider pilots, he pursued the development
of TherMap up to the present version.
The feedback by pilots and experts
has permitted to continuously improve the model and to update this
site with still better maps. In this respect particular thanks go
to Alfred Ultsch, for his additional validations on the basis
of flightlogs, his publication of the findings (ref. 9), and for his
pertinent improvement proposals. Further thanks go to Iakov Shrage,
a top competition glider pilot besides 21500 hours as an airline pilot,
who encouraged the extension of this site to also cover the region
of Slovakia. The further evolution, the extension to US regions down
to 35 degrees latitude, with very high sun elevations during summer
months, became possible thanks to the initiative and practical advice
of Sergio Colasevic. This step also required further developments
to make the maps more readable.
Can the application behind
TherMap be purchased?
It might of course be interesting to make available the source code
used to generate the maps. The developments do however continue. If
the source code was distributed, the product would have to be wrapped
up as a professional package with regular updating procedures, to
ensure that the users would always dispose of the latest version.
This would however result in a costly commercial approach requiring
considerable resources. In addition it would also be in conflict with
the conditions set by SRTM, the distributor of the satellite data,
which is basically only made available for noncommercial use.
What possibilities exist to
use the TherMap model for topographically smoother regions ?
This is a question we continue to ask ourselves. With the introduction
of the thermal pressure model it became possible to produce maps for
regions outside the higher mountains, such as the Jura. In topographically
still less pronounced regions the local variations of the surface
becomes smaller and more scattered, making it more difficult to identify
topographically induced thermal takeoff areas. In addition the flight
level above ground are usually higher than in mountain areas, making
it also more difficult to validate possible thermal models on the
basis of flight track data. However thermals always have a physical
cause. It may therefore be possible that other than orographic causes
may some day be identified and used to produce similar maps for flatter
exist to generate TherMap images reflecting the actual local meteorological
conditions at a given time?
This question can probably only be answered in the longer term. In
Europe diagrams showing the hourly meteorological evolution are available
for regions of 50 to 100 kilometers. On this basis in would, in principle,
be possible to generate corresponding TherMap presentations. The data
would however have to be paid, because it would have to be supplied
for automatic processing. In addition there would also be the costs
of daily processing. Finally one has to keep in mind that the actual
demand for such highly detailed maps would be rather marginal.
Can TherMap be extended to other region?
The development of TherMap has also been the result of intensive
information exchange with experts and experienced pilots, because
the models represent only partly physical processes, the
other parts being rather models of the perception of experienced
pilots. For any new region to be addressed it is therefore crucial
to have competent and experienced counterparts to properly adjust
and validate the models, if necessary. With pertinent help of local
colleagues it would however be a pleasure to extend the scope of
TherMap to further suitable regions.
Can the maps also be used by paragliders?
The publications of the TherMap maps has also been well received
by the paragliding community. Due to their slower speed and lower
gliding ratio, paragliders are more interested in the hotspots within
more limited regions. In countries such as Switzerland,
paragliding "highway" maps have been successfully established
on the basis of statistical analyses of flight logs. Therefore the
resulting routes are more determined by the preferred paraglider
takeoff locations, hence leaving out many interesting areas known
by glider pilots and shown on TherMap.