 |
| Titel |
GPS Tomography: Water Vapour Monitoring for Germany |
| VerfasserIn |
Michael Bender, Galina Dick, Jens Wickert, Armin Raabe |
| Konferenz |
EGU General Assembly 2010
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250036182
|
|
|
|
|
|
| Zusammenfassung |
| Ground based GPS atmosphere sounding provides numerous atmospheric quantities
with a high temporal resolution for all weather conditions. The spatial resolution
of the GPS observations is mainly given by the number of GNSS satellites and
GPS ground stations. The latter could considerably be increased in the last few
years leading to more reliable and better resolved GPS products. New techniques
such as the GPS water vapour tomography gain increased significance as data from
large and dense GPS networks become available. The GPS tomography has the
potential to provide spatially resolved fields of different quantities operationally, i. e.
the humidity or wet refractivity as required for meteorological applications or the
refraction index which is important for several space based observations or for precise
positioning.
The number of German GPS stations operationally processed by the GFZ in
Potsdam was recently enlarged to more than 300. About 28000 IWV observations and
more than 1.4 millions of slant total delay data are now available per day with a
temporal resolution of 15 min and 2.5 min, respectively. The extended network leads
not only to a higher spatial resolution of the tomographically reconstructed 3D
fields but also to a much higher stability of the inversion process and with that to an
increased quality of the results. Under these improved conditions the GPS tomography
can operate continuously over several days or weeks without applying too tight
constraints.
Time series of tomographically reconstructed humidity fields will be shown and different
initialisation strategies will be discussed: Initialisation with a simple exponential profile,
with a 3D humidity field extrapolated from synoptic observations and with the
result of the preceeding reconstruction. The results are compared to tomographic
reconstructions initialised with COSMO-DE analyses and to the corresponding model
fields.
The inversion can be further stabilised by making use of independent adequately
weighted observations, such as synoptic observations or IWV data. The impact of such
observations on the quality of the tomographic reconstruction will be discussed
together with different alternatives for weighting different types of observations. |
|
|
|
|
|
|