USE OF SATELLITE SAR DATA FOR SEISMIC RISK MANAGEMENT: RESULTS FROM THE PRE-OPERATIONAL ASI-SIGRIS PROJECT

In the framework of the National Space Programme, and of the European GMES Programme, the Italian Space Agency (ASI) has funded several pilot projects aimed at demonstrating the full potential of Earth Observation data in the monitoring and management of natural hazards. The SIGRIS (Earth Observation System for Seismic Risk Management) pilot project has developed a hardware/software infrastructure for the generation of decision support products for the seismic risk management. A pre-operational demonstration of the SIGRIS system is being carried out since June 2009 and various products to be used by civil protection authorities in either the Knowledge & Prevention or Crisis Management phases of seismic risk management, have been generated. SIGRIS products to support the Knowledge & Prevention activities are based on the integration of satellite and ground-based observations to constrain analytical and numerical models of the tectonic strain accumulation and of its long-term effects on the earthquake source. They include crustal deformation maps from time series DInSAR and GPS, and fault models to improve the seismic hazard assessment. SIGRIS products for the Crisis Management phase are instead focused on the quick generation of value added information needed to devise damage or event scenarios, and typically consist of damage assessment maps from high resolution optical and SAR data, co-seismic displacements maps from DInSAR analysis, seismic source models, maps of earthquake-induced environmental effects (landslides, surface fractures, ecc.). For these products a near-real time capability is required and new constellations, as COSMO-SkyMed , can now provide the necessary temporal revisit to fulfil this need. The SIGRIS system is also depending on other SAR satellites to ensure a faster and better coverage of the disaster areas: ENVISAT, Radarsat, TerraSar X, ALOS. We will present examples of the SIGRIS decision support products based on the integration of Earth Observation and ground data and discuss important issues related to disaster applications, as EO data programming, fast data access, data archival

Satellite Lidar Measurements as a Critical New Global Ocean Climate Record

The year 2023 marked the tenth anniversary of the first published description of global ocean plankton stocks based on measurements from a satellite lidar. Diverse studies have since been conducted to further refine and validate the lidar retrievals and use them to discover new characteristics of plankton seasonal dynamics and marine animal migrations, as well as evaluate geophysical products from traditional passive ocean color sensors. Surprisingly, all of these developments have been achieved with lidar instruments not designed for ocean applications. Over this same decade, we have witnessed unprecedented changes in ocean ecosystems at unexpected rates and driven by a multitude of environmental stressors, with a dominant factor being climate warming. Understanding, predicting, and responding to these ecosystem changes requires a global ocean observing network linking satellite, in situ, and modeling approaches. Inspired by recent successes, we promote here the creation of a lidar global ocean climate record as a key element in this envisioned advanced observing system. Contributing to this record, we announce the development of a new satellite lidar mission with ocean-observing capabilities and then discuss additional technological advances that can be envisioned for subsequent missions. Finally, we discuss how a potential near-term gap in global ocean lidar data might, at least partially, be filled using on-orbit or soon-to-be-launched lidars designed for other disciplinary purposes, and we identify upcoming needs for in situ support systems and science community development

The MOCAST+ Study on a Quantum Gradiometry Satellite Mission with Atomic Clocks

In the past twenty years, satellite gravimetry missions have successfully provided data for the determination of the Earth static gravity field (GOCE) and its temporal variations (GRACE and GRACE-FO). In particular, the possibility to study the evolution in time of Earth masses allows us to monitor global parameters underlying climate changes, water resources, flooding, melting of ice masses and the corresponding global sea level rise, all of which are of paramount importance, providing basic data on, e.g. geodynamics, earthquakes, hydrology or ice sheets changes. Recently, a large interest has developed in novel technologies and quantum sensing, which promise higher sensitivity, drift-free measurements, and higher absolute accuracy for both terrestrial surveys and space missions, giving direct access to more precise long-term measurements. Looking at a time frame beyond the present decade, in the MOCAST+ study (MOnitoring mass variations by Cold Atom Sensors and Time measures) a satellite mission based on an “enhanced” quantum payload is proposed, with cold atom interferometers acting as gravity gradiometers, and atomic clocks for optical frequency measurements, providing observations of differences of the gravitational potential. The main outcomes are the definition of the accuracy level to be expected from this payload and the accuracy level needed to detect and monitor phenomena identified in the Scientific Challenges of the ESA Living Planet Program, in particular Cryosphere, Ocean and Solid Earth. In this paper, the proposed payload, mission profile and preliminary platform design are presented, with end-to-end simulation results and assessment of the impact on geophysical applications

Gamma-Ray Burst observations by the high-energy charged particle detector on board the CSES-01 satellite between 2019 and 2021

In this paper we report the detection of five strong Gamma-Ray Bursts (GRBs) by the High-Energy Particle Detector (HEPD-01) mounted on board the China Seismo-Electromagnetic Satellite (CSES-01), operational since 2018 on a Sun-synchronous polar orbit at a $\sim$ 507 km altitude and 97$^\circ$ inclination. HEPD-01 was designed to detect high-energy electrons in the energy range 3 - 100 MeV, protons in the range 30 - 300 MeV, and light nuclei in the range 30 - 300 MeV/n. Nonetheless, Monte Carlo simulations have shown HEPD-01 is sensitive to gamma-ray photons in the energy range 300 keV - 50 MeV, even if with a moderate effective area above $\sim$ 5 MeV. A dedicated time correlation analysis between GRBs reported in literature and signals from a set of HEPD-01 trigger configuration masks has confirmed the anticipated detector sensitivity to high-energy photons. A comparison between the simultaneous time profiles of HEPD-01 electron fluxes and photons from GRB190114C, GRB190305A, GRB190928A, GRB200826B and GRB211211A has shown a remarkable similarity, in spite of the different energy ranges. The high-energy response, with peak sensitivity at about 2 MeV, and moderate effective area of the detector in the actual flight configuration explain why these five GRBs, characterised by a fluence above $\sim$ 3 $\times$ 10$^{-5}$ erg cm$^{-2}$ in the energy interval 300 keV - 50 MeV, have been detected.Comment: Accepted for publication in The Astrophysical Journal (ApJ

USE OF SATELLITE SAR DATA FOR SEISMIC RISK MANAGEMENT: RESULTS FROM THE PRE-OPERATIONAL ASI-SIGRIS PROJECT

In the framework of the National Space Programme, and of the European GMES Programme, the Italian Space Agency (ASI) has funded several pilot projects aimed at demonstrating the full potential of Earth Observation data in the monitoring and management of natural hazards. The SIGRIS (Earth Observation System for Seismic Risk Management) pilot project has developed a hardware/software infrastructure for the generation of decision support products for the seismic risk management. A pre-operational demonstration of the SIGRIS system is being carried out since June 2009 and various products to be used by civil protection authorities in either the Knowledge & Prevention or Crisis Management phases of seismic risk management, have been generated. SIGRIS products to support the Knowledge & Prevention activities are based on the integration of satellite and ground-based observations to constrain analytical and numerical models of the tectonic strain accumulation and of its long-term effects on the earthquake source. They include crustal deformation maps from time series DInSAR and GPS, and fault models to improve the seismic hazard assessment. SIGRIS products for the Crisis Management phase are instead focused on the quick generation of value added information needed to devise damage or event scenarios, and typically consist of damage assessment maps from high resolution optical and SAR data, co-seismic displacements maps from DInSAR analysis, seismic source models, maps of earthquake-induced environmental effects (landslides, surface fractures, ecc.). For these products a near-real time capability is required and new constellations, as COSMO-SkyMed , can now provide the necessary temporal revisit to fulfil this need. The SIGRIS system is also depending on other SAR satellites to ensure a faster and better coverage of the disaster areas: ENVISAT, Radarsat, TerraSar X, ALOS. We will present examples of the SIGRIS decision support products based on the integration of Earth Observation and ground data and discuss important issues related to disaster applications, as EO data programming, fast data access, data archival.PublishedBergen, NO1.10. TTC - Telerilevamentoope

Linear Dispersion Relation and Depth Sensitivity to Swell Parameters: Application to Synthetic Aperture Radar Imaging and Bathymetry

Long gravity waves or swell dominating the sea surface is known to be very useful to estimate seabed morphology in coastal areas. The paper reviews the main phenomena related to swell waves propagation that allow seabed morphology to be sensed. The linear dispersion is analysed and an error budget model is developed to assess the achievable depth accuracy when Synthetic Aperture Radar (SAR) data are used. The relevant issues and potentials of swell-based bathymetry by SAR are identified and discussed. This technique is of particular interest for characteristic regions of the Mediterranean Sea, such as in gulfs and relatively close areas, where traditional SAR-based bathymetric techniques, relying on strong tidal currents, are of limited practical utility

Gravity from space by Cold Atom Interferometry: the MOCASS study and preliminary results

MOCASS (Mass Observation with Cold Atom Sensors in Space) is an on-going study project funded by the Italian Space Agency in the framework of preparatory activities for future missions and payloads of Earth Observation. The object of the proposal is an innovative satellite gravity mission based on advanced cold atom interferometry (CAI) accelerometers, with the aim of modelling the static and time-variable gravity field of the Earth with high accuracy and resolution and of monitoring mass variations that occur on and below the Earth surface. The basic idea is a GOCE mission follow-on, launching a unique spacecraft with an on-board instrument capable of measuring some functionals of the Earth gravitational potential. The improvement with respect to the GOCE mission concept can only be achieved by going beyond the technology of electrostatic gradiometers, taking advantage of a new generation of sensors, such as cold atom interferometers. In the framework of the MOCASS study, the instrument characteristics are defined in terms of long-term stability, accuracy, and spectral responses. Then simulations on gravity field recovery based on the space-wise approach already used for the GOCE data processing are implemented. Finally an analysis on the geophysical signals that can be detected given the simulated mission performance are performed, with particular attention to hydrologic and tectonic modelling of changing masses. First simulations have already been performed by considering the GOCE orbit parameters but assuming that a CAI gradiometer is on board the spacecraft. This allows direct comparisons between GOCE and MOCASS performances. Instrument error spectra have been defined depending on the orbit and CAI configurations, all of them characterized by a flat error spectrum in the low frequencies, differently from the one of the GOCE electrostatic accelerometers. Given the error spectrum and the interferometer integration spectral response, simulated observations have been produced and processed by the space-wise approach, which basically consists in a sequential application of a Wiener filter, a local collocation gridding and a spherical harmonic analysis. From sample statistics, the accuracy of the recoverable gravity field model can then be evaluated and compared with the expected gravity signal from selected geophysical phenomena, e.g. orogen geodynamics and glacier melting. Although the study is at this time not complete, these preliminary investigations show promising results

Activation of the SIGRIS monitoring system for ground deformation mapping during the Emilia 2012 seismic sequence, using COSMO-SkyMed InSAR data

On May 20, 2012, at 02:03 UTC, a moderate earthquake of local magnitude, Ml 5.9 started a seismic sequence in the central Po Plain of northern Italy The mainshock occurred in an area where seismicity of comparable magnitude has neither been recorded nor reported in the historical record over the last 1,000 years. The aftershock sequence evolved rapidly near the epicenter, with diminishing magnitudes until May 29, 2012, when at 07:00 UTC a large earthquake of Ml 5.8 occurred 12 km WSW of the mainshock, starting a new seismic sequence in the western area; a total of seven earthquakes with Ml >5 occurred in the area between May 20 and June 3, 2012. Immediately after the mainshock, the Italian Department of Civil Protection requested the Italian Space Agency to activate the Constellation of Small Satellites for Mediterranean Basin Observation (COSMO-SkyMed) to provide Interferometric Synthetic Aperture Radar (InSAR) coverage of the area. COSMO-SkyMed consists of four satellites in a 16-day repeat-pass cycle, with each carrying the same SAR payload. In the current orbital configuration, within each 16-day cycle, image pairs with temporal baselines of 1, 3, 4 and 8 days can be formed from the images acquired by the four different sensors. Combined with the availability of a wide range of electronically steered antenna beams with incidence angles ranging from about 16˚ to 50˚ at near-range, this capability allows trade-offs between temporal and spatial coverage to be exploited during acquisition planning. A joint team involving the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and the Istituto per il Rilevamento Elettromagnetico dell'Ambiente (IREA-CNR) was activated to generate InSAR-based scientific products to support the emergency management. In this framework, the ASI and DPC requested that INGV activated the Space-based Monitoring System for Seismic Risk Management (SIGRIS). SIGRIS consists of a hardware/software infrastructure that is designed to provide the DPC with value-added information products in the different phases of the seismic cycle. During earthquake emergencies, its goal is to rapidly provide decision-support products, such as validated ground-displacement maps and seismic source models. This study reports the details of the activation of the SIGRIS system in the case of the Emilia sequence. It provides a description of the COSMO-SkyMed datasets and processing procedures, as well as selected interferometric results for the coseismic and post-seismic ground deformation. […

A Prototype System for Flood Monitoring Based on Flood Forecast Combined with COSMO-SkyMed and Sentinel-1 Data

The use of synthetic aperture radar (SAR) data is presently well established in operational services for flood man- agement. However, some events might be missed because of the limited area that can be observed through a SAR image and the need of programming SAR acquisitions in advance. To tackle these problems, it is possible to setup a system that is able to trigger the SAR acquisitions based on flood forecasts and to take advantage of the various satellite SAR sensors that are presently operating. On behalf of the Italian Civil Protection Department (DPC), a proto- type of this kind of system has been setup and preliminary tested, using COSMO-SkyMed (CSK) and Sentinel-1 (S-1) data, to mon- itor the Po River (Northern Italy) flood occurred in November 2014. This paper presents the prototype system and describes in detail the near real-time flood mapping algorithm implemented in the system. The algorithm was previously developed to classify CSK images, and is modified here in order to be applied to S-1 data too. The major outcomes of the monitoring of the Po River flood are also analyzed in this paper, highlighting the importance of the in advance programming of the radar acquisitions. Results demonstrate the reliability of the flood predictions provided by the model and the accuracy of the flood mapping algorithm. It is also shown that, when CSK and S-1 data are simultaneously acquired, their joint use allows for an interpretation of some ambiguous radar signatures in agricultural areas