ON THE INTERFEROMETRIC AND POLARIMETRIC CAPABILITIES OF THE ARGENTINIAN L-BAND SARAT SYSTEM

Abstract. In this paper, some results obtained through the processing of data acquired from the Argentinian L-band SARAT system are presented. SARAT is an airborne system that was developed as a first conceptual step toward the design of the Argentinian L-Band satellite mission SAOCOM-1. In particular, some studies relevant to the data focusing, and also regarding the interferometric and polarimetric capabilities of the SARAT system are hereby shown. The considered dataset, relevant to an area located in the Cordoba province, Argentina, has been provided by the National Commission of Space Activities of Argentina (CONAE). This work has been developed in the framework of a collaboration between the Italian Space Agency (ASI) and CONAE

Interferometric Assessment of SAOCOM-1 TOPSAR Data

— SAOCOM-1 constellation operates in three acquisition modes: Stripmap (SM), TOPSAR Narrow (TNA and TNB) nd TOPSAR Wide (TW). Since repeat pass SAOCOM-1 TOPSAR acquisitions are not synchronized, the generation of the related interferometric products is not guaranteed, as it happens instead for the synchronized repeat pass TOPSAR acquisitions, such as those of Sentinel-1. In this work, we assess the suitability of SAOCOM-1 TOPSAR acquisitions for generating interferometric products. To this aim, we first discuss the constraints that must be fulfilled by the repeat pass non-synchronized TOPS acquisitions in order to make it feasible the generation of usable interferograms. Then, we verify if SAOCOM-1 TOPSAR acquisitions fulfill these constraints. For this purpose, we present an analysis based on the use of a data set composed by 18 TNB images relevant to a single subswath illuminating a region located in the South-West of Argentina.From this data set, we were able to select 48 pairs that guarantee the spectral superposition needed for interferometric purposes. We verified that the 50% of these 48 pairs fulfill the constraintrequired to avoid in the corresponding interferograms the presence of non-coherent azimuth stripes, whose azimuth extension depends on one side on the mis-synchronization percentage between the repeat pass acquisitions, and on the other side on the overlapping percentage between adjacent bursts of the same acquisition. Summing up, the presented analysis proves the potential of SAOCOM-1 TOPSAR acquisitions to obtain interferometric products, despite the absence of bursts synchronization between repeat pass acquisitions.Fil: Euillades, Jorge Alejandro. Universidad Nacional de Cuyo. Facultad de Ingenieria. Instituto de Capacitación Especial y Desarrollo de Ingeniería Asistida por Computadora; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Roa, Yenni L.. Centre National de la Recherche Scientifique; FranciaFil: Euillades, Leonardo Daniel. Universidad Nacional de Cuyo. Facultad de Ingenieria. Instituto de Capacitación Especial y Desarrollo de Ingeniería Asistida por Computadora; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería; ArgentinaFil: Euillades, Pablo Andrés. Universidad Nacional de Cuyo. Facultad de Ingenieria. Instituto de Capacitación Especial y Desarrollo de Ingeniería Asistida por Computadora; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Rosell, Patricia Alejandra. Universidad Nacional de Cuyo. Facultad de Ingenieria. Instituto de Capacitación Especial y Desarrollo de Ingeniería Asistida por Computadora; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Solarte, Edinson A.. Centre National de la Recherche Scientifique; FranciaFil: Perna, Stefano. Centre National de la Recherche Scientifique; Franci

Atmospheric corrections in interferometric synthetic aperture radar surface deformation – a case study of the city of Mendoza, Argentina

Differential interferometry is a remote sensing technique that allows studying crustal deformation produced by several phenomena like earthquakes, landslides, land subsidence and volcanic eruptions. Advanced techniques, like small baseline subsets (SBAS), exploit series of images acquired by synthetic aperture radar (SAR) sensors during a given time span. <br><br> Phase propagation delay in the atmosphere is the main systematic error of interferometric SAR measurements. It affects differently images acquired at different days or even at different hours of the same day. So, datasets acquired during the same time span from different sensors (or sensor configuration) often give diverging results. Here we processed two datasets acquired from June 2010 to December 2011 by COSMO-SkyMed satellites. One of them is HH-polarized, and the other one is VV-polarized and acquired on different days. <br><br> As expected, time series computed from these datasets show differences. We attributed them to non-compensated atmospheric artifacts and tried to correct them by using ERA-Interim global atmospheric model (GAM) data. With this method, we were able to correct less than 50% of the scenes, considering an area where no phase unwrapping errors were detected. We conclude that GAM-based corrections are not enough for explaining differences in computed time series, at least in the processed area of interest. We remark that no direct meteorological data for the GAM-based corrections were employed. Further research is needed in order to understand under what conditions this kind of data can be used

On the Interferometric and Polarimetric Capabilities of the Argentinian L-Band Sarat System

In this paper, some results obtained through the processing of data acquired from the Argentinian L-band SARAT system are presented. SARAT is an airborne system that was developed as a first conceptual step toward the design of the Argentinian L- Band satellite mission SAOCOM-1. In particular, some studies relevant to the data focusing, and also regarding the interferometric and polarimetric capabilities of the SARAT system are hereby shown. The considered dataset, relevant to an area located in the Cordoba province, Argentina, has been provided by the National Commission of Space Activities of Argentina (CONAE). This work has been developed in the framework of a collaboration between the Italian Space Agency (ASI) and CONAE

Monitoring volcano deformation at La Soufrière, St Vincent during the 2020–21 eruption with insights into its magma plumbing system architecture

Measurements of surface deformation provide valuable insight into sub-volcanic processes operating before, during and after eruptions. Here, we investigate the drivers behind the 2020-21 effusive-explosive episode at La Soufrière volcano in St. Vincent using Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data between 2018 and 2021, and geodetic modelling. We observe inflation up to six months before the start to the effusive phase, which continued as the dome extruded. Once the eruption transitioned to the explosive phase, the volcano rapidly deflated, the bulk happening within the first three days of explosions. Our analytical modelling distinguishes three pressure source depth ranges contributing to this eruptive episode: 16 - 20, ∼6 and <1 kilometres. Deformation data are therefore in line with a vertically extensive magmatic system being tapped pre- and syn-eruption with interaction between deep and shallow reservoirs by ascending magma batches. The combined use of GPS and InSAR proved to be instrumental for constraining the deformation field active during this eruptive episode. The direction of future geodetic monitoring at La Soufrière should therefore utilise both techniques with a view towards maximising coverage while making up for shortfalls in station upkeep and variations in satellite overpass regularity.Fil: Camejo Harry, Michal. University of Oxford; Reino Unido. The University of the West Indies; Trinidad y TobagoFil: Pascal, Karen. The University of the West Indies; Trinidad y TobagoFil: Euillades, Pablo Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingenieria. Instituto de Capacitación Especial y Desarrollo de Ingeniería Asistida por Computadora; ArgentinaFil: Grandin, Raphaël. Institut de Physique Du Globe de Paris; FranciaFil: Hamling, Ian. Gns Science; Nueva ZelandaFil: Euillades, Leonardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingenieria. Instituto de Capacitación Especial y Desarrollo de Ingeniería Asistida por Computadora; ArgentinaFil: Contreras Arratia, Rodrigo. The University of the West Indies; Trinidad y TobagoFil: Ryan, Graham A.. The University of the West Indies; Trinidad y TobagoFil: Latchman, Joan L.. The University of the West Indies; Trinidad y TobagoFil: Lynch, Lloyd. The University of the West Indies; Trinidad y TobagoFil: Jo, Minjeong. Universities Space Research Association; Estados Unido

Fig. S6: Monitoring volcano deformation at La Soufrière, St Vincent during the 2020–21 eruption with insights into its magma plumbing system architecture

Unwrapped interferogram using ALOS-2 images obtained between 07/04/2021 and 21/04/2021 (ascending track, path 36 and frame 250). This exemplifies the inability of ALOS-2 radar to detect deformation related to the explosive phase (9–22 April 2021) due to the low signal-to-noise ratio and widespread lack of coherence

Fig. S3: Monitoring volcano deformation at La Soufrière, St Vincent during the 2020–21 eruption with insights into its magma plumbing system architecture

Vertical cGPS time-series for SVGB, SVGG, SVGF and SVGR stations projected into SAOCOM radar LOS with respect to SVGK reference station. Red triangles indicate dates of the scenes used before and after the explosive phase (06/01/2021 and 14/03/2022)

Fig. S1: Monitoring volcano deformation at La Soufrière, St Vincent during the 2020–21 eruption with insights into its magma plumbing system architecture

Surface deformation in the 2018–21 time-interval from Sentinel-1 small-baseline analysis. Top: mean line-of-sight velocity from Sentinel-1 descending track 156. Positive velocity corresponds to motion towards the satellite. The image is in radar geometry, and has been flipped and rotated so as to align approximately with a geographical orientation. X- and Y-coordinates are the number of pixels in range and azimuth, respectively. Bottom: time-series of displacement for five selected pixels. Locations of the pixels are displayed with the same symbols on the upper panel. Orange dashed line shows the onset of the effusive phase (27 December 2020)

Fig. S4: Monitoring volcano deformation at La Soufrière, St Vincent during the 2020–21 eruption with insights into its magma plumbing system architecture

Distribution of best-fitting model solutions for I2 pre-eruption (effusive) deformation using (a) point-, (b) dyke- and (c) penny-shaped crack sources. Modelled dyke using Sentinel-1 data for I3 phase from Joseph et al. (2022) shown as black open rectangle