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Application of ray-tracing through the high resolution numerical weather model HIRLAM applying the Conformal Theory of Refraction

Susana Garcia Espada (Institutionen för rymd- och geovetenskap, Rymdgeodesi och geodynamik) ; Rüdiger Haas (Institutionen för rymd- och geovetenskap, Rymdgeodesi och geodynamik) ; Francisco Colomer Sanmartin
Proceedings of the 20th Meeting of the European VLBI Group for Geodesy and Astrometry (1864-1113). p. 133-137. (2011)
[Konferensbidrag, övrigt]

In space geodetic techniques like VLBI and GPS, accuracy is limited by atmospheric propagation effects by neutral atmosphere in the troposphere. In recent years numerical weather models (NWM) have been applied to improve mapping functions which are used for tropospheric delay modeling in VLBI and GPS data analyses. A troposphere correction model applying ray-tracing through the Limited Area numerical weather prediction (NWP) HIRLAM 3D-VAR model and applying the Conformal Theory of Refraction is developed. The advantages of HIRLAM model are the high spatial resolution (0.2◦x0.2◦) and the high temporal resolution in prediction mode (every 3 hours). The advantages of the Conformal Theory of Refraction (Moritz, 1967) is that the atmospheric propagation effects are evaluated along the line of sight and the known vacuum elevation angle is used so no iterative calculations are needed. When ray-tracing through HIRLAM profiles and calculating the slant delays using the Conformal Theory of Refraction, we include the effect of an inhomogeneous atmosphere in the slant delays values.

Nyckelord: HIRLAM, NWM, ray-tracing, Conformal Theory of Refraction



Denna post skapades 2011-10-10. Senast ändrad 2016-05-24.
CPL Pubid: 147017