Targeting Optimal Use of GPS Humidity Measurements in Meteorology
The TOUGH project is now finished. It has been a succesful project. The
main results from TOUGH are now being utilised in the systems
for operational use of near real time ground based GPS data in
meteorology that are emerging. Both when it comes to establishing
a GPS delay observing system (see
E-GVAP) and regarding use of GPS delays in numerical weather
prediction. To study in various degrees of detail
the results from TOUGH follow the links under
"Results" en the left-hand column.
Knowledge of the atmospheric distribution of water vapour is of key
importance in weather prediction and climate research. It is tightly
coupled to processes like energy transfer, precipitation, and is an
important greenhouse gas. However, currently there is lack of knowledge
about the actual humidity field, both due to a shortage of observations
and a sub-optimal handling of humidity in the data assimilation
systems, which are used to make estimates of the actual atmospheric
field. Such fields are used to start numerical weather prediction and
for climate monitoring. Global Positioning System (GPS) signals are
particularly sensitive to water vapour. In the TOUGH project we have
and refined methods enabling optimal use of GPS data from existing
European GPS stations in numerical weather prediction models, and
assessed the impact of such data upon the skill of weather forecasts.
TOUGH was an interdiciplinary project between 15 institutes with expertise
in the GPS system and meteorological institutes, coordinted by the
Danish Meteorological Institute (DMI). It ran from February 2003 to
TOUGH is a shared-cost project (contract EVG1-CT-2002-00080)
co-funded by the Research DG of the European Commission within the
RTD activities of the Environment and Sustainable Development
sub-programme (5'th Framework Programme).
TOUGH is open to collaboration with other institutes working in the field.
An important part of the project is to make other potential users of ground
based GPS atmospheric products aware of this type of observations.
For further information, please, utilise the links on the TOUGH homepage
or contact the TOUGH team at firstname.lastname@example.org.
These figures shows a case with significant improvement of a forecast
when ground based GPS observations are included among the observations
specifying the field from which the computer calculates the exptected
future weather. To the left is the observed rain over a 12 hour period.
Below are the predicted amounts over the same period. Green,
yellow, red, and violet colors indicate severe large amounts of rain,
with violet being the highest.
Forecast rain with GPS
Forecast rain without GPS