G05 GNSS++: Emerging Technologies and Applications

IAG (Geodesy)

25-Jun-2015, 08:30 - 10:00

Abstract content:

Tropospheric profiles of total refractivity from the collocation software COMEDIE

The refractivity of the troposphere is measured in GNSS (Global Navigation Satellite Systems) meteorology by zenith total delay (ZTD) and troposphere gradients in north and east directions. The collocation method can be applied to reconstruct the troposphere conditions based on GNSS and meteorological observations in an interpolation model.

In this study we reconstructed the total refractivity profiles over a western part of Switzerland using the least-squares collocation software COMEDIE (Collocation of Meteorological Data for Interpretation and Estimation of Tropospheric Pathdelays). Different datasets were included into collocation algorithms: total refractivity calculated from meteorological parameters at ground-based SwissMetNet sites as well as GNSS derived ZTD and horizontal gradients of ZTD from Automated GNSS Network for Switzerland (AGNES). The refractivity fields were compared to the values on the reference radiosonde station in Payerne. We are also investigating the application of collocation algorithms to improve modeling of refractivity field in Poland and Australia.

We presumed that introducing the horizontal gradients will improve the interpolation, but for the vertical interpolation case study in Switzerland at Payerne the refractivity field from the dataset with gradients was worse by about 0.5 ppm than the interpolation without gradients. Currently, we are actively researching the reason for results degradation (gradient noise, orography of Switzerland, parameterization problems).

K. Wilgan1, F. Hurter2, A. Geiger2, W. Rohm1, J. Bosy1.
1Wroclaw University of Environmental and Life Sciences, Institute of Geodesy and Geoinformatics, Wroclaw, Poland.
2ETH Zurich, Geodesy and Geodynamics Lab, Zurich, Switzerland.


GNSS meteorology     refractivity field     collocation     ZTD gradients