Uso de interferometría diferencial para monitorear deformaciones de terreno en la comuna de Corvara, provincia de Bolzano, Italia

Tesis (Magister en Aplicaciones Espaciales de Alerta y Respuesta Temprana a Emergencias)--Universidad Nacional de Córdoba, Facultad de Matemática, Astronomía, Física y Computación, 2016.Maestría conjunta con el Instituto de Altos Estudios Espaciales "Mario Gulich"-CONAE.El deslizamiento de Corvara (Alpes Italianos) se encuentra activo desde hace más de 10.000 años. Campañas de monitoreo GPS en los últimos 15 años han revelado vectores de deformación de hasta 50 metros para solo un año (Caroli, 2009). Para ese trabajo el deslizamiento de Corvara se toma como caso de estudio para comparar diferentes imágenes SAR y diferentes técnicas para medir deformaciones en el terreno, y para evaluar la factibilidad del procesado interferométrico (InSAR) en estas aplicaciones. Por un lado se prueba el algoritmo Permanent Scatterers (PS) con 27 imágenes Cosmo Skymed en órbita descendente, y por el otro se procesan dos conjuntos de 16 imágenes Sentinel-1A (banda C) en órbita ascendente y descendente con el algoritmo Small Baselines Subset (SBAS).The Corvara Landslide (Italian Alps) has been active for over 10,000 years, and systematic ground GPS monitoring within the last 15 years has revealed displacement vectors of up to 50 meters for only one year (Caroli, 2009). In this work the Corvara landslide is taken as case study in order to compare different spaceborne SAR images and techniques to retrieve ground deformation and to evaluate the feasibility of Inteferometry (InSAR) processing for these applications. On one side the Permanent Scatterers (PS) algorithm is used to process a set of 27 Cosmo Skymed images (X-band) in descending mode acquired over the study area. The presence of 16 artificial Corner Reflectors, designed according to Cosmo Skymed wavelength and acquisition geometry, has been crucial for the implementation of this technique in a rapidly moving and poorly coherent study area. On the other side two datasets of 16 Sentinel-1A images C-band) in ascending and descending mode are processed with the Small Baselines Subset (SBAS) algorithm, where achieving a coherent enough combination of interferometric pairs without discarding large portions of data becomes essential. Both families of algorithms are intended to generate deformation time series and to retrieve parameters such as deformation velocity, terrain height and cumulative displacement. The Corner Reflectors are also used as ground control points to validate the time series derived from the three datasets. Local environmental factors and sensor characteristics such as the monitored time period, magnitude of the measured movements, difficulties related to X and C band wavelengths and algorithms limitations are analyzed in order to understand the performance of these techniques in a mountainous landslide area like Corvara

Assessment of L-Band SAOCOM InSAR coherence and its comparison with C-Band: A case study over managed forests in Argentina

The objective of this work is to analyze the behavior of short temporal baseline interferomet ric coherence in forested areas for L-band spaceborne SAR data. Hence, an exploratory assessment of the impacts of temporal and spatial baselines on coherence, with emphasis on how these effects vary between SAOCOM-1 L-band and Sentinel-1 C-band data is presented. The interferometric coherence is analyzed according to different imaging parameters. In the case of SAOCOM-1, the impacts of the variation of the incidence angle and the ascending and descending orbits over forested areas are also assessed. Finally, short-term 8-day interferometric coherence maps derived from SAOCOM-1 are especially addressed, since this is the first L-band spaceborne mission that allows us to acquire SAR images with such a short temporal span. The analysis is reported over two forest-production areas in Argentina, one of which is part of the most important region in terms of forest plantations at the national level. In the case of SAOCOM, interferometric configurations are characterized by a lack of control on the spatial baseline, so a zero-baseline orbital tube cannot be guaranteed. Nevertheless, this spatial baseline variability is crucial to exploit volume decorrelation for forest monitoring. The results from this exploratory analysis demonstrates that SAOCOM-1 short temporal baseline interferograms, 8 to 16 days, must be considered in order to mitigate temporal decorrelation effects and to be able to experiment with different spatial baseline configurations, in order to allow appropriate forest monitoring.This research was funded by the project INTERACT PID2020-114623RB-C32 funded by the Spanish MCIN /AEI /10.13039 /501100011033.Peer ReviewedPostprint (published version

Assessment of L-Band SAOCOM InSAR Coherence and Its Comparison with C-Band: A Case Study over Managed Forests in Argentina

The objective of this work is to analyze the behavior of short temporal baseline interferometric coherence in forested areas for L-band spaceborne SAR data. Hence, an exploratory assessment of the impacts of temporal and spatial baselines on coherence, with emphasis on how these effects vary between SAOCOM-1 L-band and Sentinel-1 C-band data is presented. The interferometric coherence is analyzed according to different imaging parameters. In the case of SAOCOM-1, the impacts of the variation of the incidence angle and the ascending and descending orbits over forested areas are also assessed. Finally, short-term 8-day interferometric coherence maps derived from SAOCOM-1 are especially addressed, since this is the first L-band spaceborne mission that allows us to acquire SAR images with such a short temporal span. The analysis is reported over two forest-production areas in Argentina, one of which is part of the most important region in terms of forest plantations at the national level. In the case of SAOCOM, interferometric configurations are characterized by a lack of control on the spatial baseline, so a zero-baseline orbital tube cannot be guaranteed. Nevertheless, this spatial baseline variability is crucial to exploit volume decorrelation for forest monitoring. The results from this exploratory analysis demonstrates that SAOCOM-1 short temporal baseline interferograms, 8 to 16 days, must be considered in order to mitigate temporal decorrelation effects and to be able to experiment with different spatial baseline configurations, in order to allow appropriate forest monitoring