Group B, Poster #206, SCEC Community Models (CXM)
Tropospheric delay estimates for InSAR derived from Vienna Mapping Function products
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Poster Presentation
2023 SCEC Annual Meeting, Poster #206, SCEC Contribution #13274 VIEW PDF
f motion and deformation. Here we present a potential improvement to the GACOS method by deriving the delay due to the stratified troposphere from physical equations rather than an empirical function, the coefficients for which are taken from the Vienna Mapping Function (VMF) products, which are derived from ray-tracing through the ECMWF numerical weather model through time. We then fix this stratified tropospheric term and estimate the turbulent part using the same inverse distance weighting method and a spline interpolation scheme, as opposed to GACOS's Iterative Tropospheric Decomposition (ITD) approach, which iterates to converge on coefficients for the two empirical terms. We see reductions in the differences (standard deviations) between the InSAR time series compared to GNSS time series projected into the InSAR line-of-sight over Southern California when applying our method compared to the GACOS correction, which improves the agreement between InSAR and GNSS in some areas while degrading it in others. The latter is observed particularly over regions of higher elevation so we conclude that our improved definition of the stratified tropospheric delay, and the application of VMF height-dependent mapping functions to the incidence angle of InSAR data, may be significant in this improvement. Our approach produces similar agreement between the two types of geodetic observations as produced by the method of Guns et al. (2022).
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Citation: Floyd, M., & Guns, K. A. (2023, 09). Tropospheric delay estimates for InSAR derived from Vienna Mapping Function products. Poster Presentation at 2023 SCEC Annual Meeting.
Keywords: InSAR, troposheric delay, GNSS
Relevant SCEC Themes:
Stress and Deformation Over Time
Community Models
