Comparison of Atmospheric Corrections Models to Satellite Interferometry Data on Kamchatka Region

In this paper, a comparative analysis of the results of applying atmospheric corrections to real displacement fields calculated by differential interferometry for the volcanic region of Kamchatka during the active phase of eruptions accompanied by significant changes in the atmospheric composition is carried out. Atmospheric corrections were calculated in two ways: 1) according to phase delay data from the online service GACOS (Generic Atmospheric Corrections Online Service), 2) by delays calculated using an empirical weather model based on data from local meteorological and GNSS stations in Kamchatka. An analysis of the effectiveness of each correction model was carried out and an assessment of their impact on the displacement fields was made. The positive result satisfying the conditions of noise reduction and tropospheric effect decrease was obtained for 74% of interferograms with GACOS correction, and for 48% of interferograms corrected using the empirical weather model. In some cases, the empirical model corrections were more accurate than the GACOS corrections. The analysis of the influence of atmospheric corrections on the displacement field has shown that in some cases the GACOS model introduces changes in the displacement field, forming regions of positive or negative anomalies that have no connection with the original displacement field. The atmospheric correction model, calculated from data of regional local meteorological stations that are not included in the international synoptic list, is useful for supplementing and developing methods for eliminating the atmospheric component of the interferometric phase. The performed study showed that in the Kamchatka region, GACOS models in many cases effectively eliminate atmospheric noise and improve the precision of the estimation of displacement fields. On the other hand, in some cases the corrections may introduce additional noise, so we do not recommend using default corrections without comparing the original and corrected displacement fields, with special attention to analysing the displacements that appeared after the introduction of corrections.

satellite interferometry, synthetic aperture radar (SAR), Kamchatka, atmospheric corrections, geostatistics, variogram