Simona Zoffoli

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 management. 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 prototype of this kind of system has been setup and preliminary tested, using COSMO-SkyMed (CSK) and Sentinel-1 (S-1) data, to monitor 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.

Development of algorithms and products for supporting the Italian hyperspectral PRISMA mission: The SAP4PRISMA project

The SAP4PRISMA is a four year research project which aims at developing algorithms and products for the future PRISMA mission. The project started on May 2010 and is now entering his full activities as the ”PRISMA like” data set has been defined and the test areas were selected. The paper describes the main project objectives and the activities realized in the first 9 months of the project.

Ground Deformation Imagery of the May Sichuan Earthquake

The magnitude Mw = 7.8 earthquake that struck Chinas Sichuan region on 12 May 2008 (Figure 1a) has been imaged by the Italian Space Agencys (ASI) Constellation of Small Satellites for the Mediterranean Basin Observation (COSMO)-SkyMed radar Earth observation satellites. Five images were available—two preseismic spotlight mode images and three strip-map mode images, two of which are preseismic and one of which is postseismic. We used two strip-map images (acquired 1 month prior to and 3 days after the earthquake) to generate the first ever X-band (i.e., microwave frequency domain, corresponding to about 3- centi meter wavelength) coseismic interferogram, which clearly shows part of the strong ground deformation caused by the fault dislocation. We also performed a change detection analysis of the same data that highlighted several changes in the radar response, presumably due to strong seismic damage, as far as 80 kilo meters away from the epicenter.

New algorithm for processing hybrid strip-map/spotlight-mode synthetic aperture radar data

We present a new algorithm for processing hybrid strip-map/spotlight SAR data which is based on a two-step focusing strategy. The first step performs an azimuth raw data filtering operation implemented via the (azimuth) convolution between the SAR data and a chirp signal with a properly chosen constant chirp rate. Following this step, the spectral folding of the azimuth raw signal spectrum is resolved and the space-variant characteristics of the system transfer function are preserved. Therefore, we can achieve the full focusing of the data by a conventional strip-map processing step implemented in frequency domain and requiring only a minor modification. The proposed algorithm is simple, efficient and has the unique feature of being suitable for processing strip-map, spotlight and hybrid strip-map/spotlight mode, the first two being particular cases of the more general last one. The presented experiments are carried out on simulated data relative to the COSMO/SkyMed sensors operating in the hybrid strip- map/spotlight mode; these results clarify the rationale of the proposed approach and confirm its validity.

L-band SAR image processing for the determination of coastal bathymetry based on swell analysis

The present paper reports on some insights in the use of Synthetic Aperture Radars (SAR) for bathymetric data retrieval by exploiting variation in swell wave parameters approaching the shoreline. Since SAR signals are unable to penetrate sea surface and to reach seabed, echoed signals from sea surface are used to investigate underwater bathymetry in coastal area. A suitable data processing methodology is proposed to properly detect swell shoaling and refraction phenomena, and to accurately measure swell parameters. The described methodology is tested by using ALOS L-band SAR images over the Gulf of Naples, Italy. A Digital Elevation Model (DEM) of the investigated area is thus obtained. Results are consistent with the values reported in the Official Nautical Chart provided by the Italian Navy Hydrographic Institute.

The SIGRIS Project: A Remote Sensing System for Seismic Risk Management

SIGRIS (SIstema di osservazione spaziale per la Gestione del RIschio Sismico) is a pilot project aiming to the realization of a system, based on satellite remote sensing data, for the seismic risk management. The project is funded by the Italian Space Agency (ASI). ASI is deeply interested on the development of new applications, using satellite data, dedicated to the monitoring and management of the natural hazards. SIGRIS is focused on providing the information services for mapping, monitoring, forecasting and awareness of seismic risk. The Earth Observation products are generated by using GPS data, optical and SAR (Synthetic Aperture Radar) images. This project deals with the data exploitation of the new Italian Earth Observation mission: COSMO-SkyMed, a constellation of four satellites equipped with an X-band high resolution SAR.

Mt. Etna volcanic plume from ASTER and HYPERION data by ASI-SRV modules

Volcanic plumes represent a visible indicator of volcanic activity. They vary in space and time, strongly influenced by the quiescent or eruptive status of the volcano. Different volcanic activities, such as volcanic clouds and plumes, inject into the atmosphere gases and aerosol at different latitudes, altitudes and with different times of residence. Released by the magma, plumes are a turbulent mixture of gases, solid particles and liquid droplets, emitted at high temperature continuously from summit craters, fumarolic fields or during eruptive episodes.

Volcanic risk system (SRV): ASI pilot project to support the monitoring of volcanic risk in Italy by means of EO data

The ASI-SRV(Sistema Rischio Vulcanico) project started at the beginning of the 2007 is funded by the Italian Space Agency (ASI) in the frame of the National Space Plan 2003-2005 under the Earth Observations section for natural risks management. Coordinated by the Istituto Nazionale di Geofisica e Vulcanologia (INGV), which is responsible at national level for the volcanic monitoring, the project has as main objective to develop a pre-operative system based on EO data and ground measurements integration to support the volcanic risk monitoring of the Italian Civil Protection Department. The project philosophy is to implement specific modules which allow to process, store and visualize through Web GIS tools EO derived parameters considering three activity phases: (1) knowledge and prevention; (2) crisis; (3) post crisis. In order to combine effectively the EO data and the ground networks measurements the system will implement a multi-parametric analysis tool, which represents and unique tool to analyze contemporaneously a large data set of data in ¿near real time¿. The SRV project will be tested his operational capabilities on three Italian volcanoes: Etna, Vesuvio and Campi Flegrei.

Towards coordinated regional multi-satellite InSAR volcano observations: results from the Latin America pilot project

Within Latin America, about 319 volcanoes have been active in the Holocene, but 202 of these volcanoes have no seismic, deformation or gas monitoring. Following the 2012 Santorini Report on satellite Earth Observation and Geohazards, the Committee on Earth Observation Satellites (CEOS) developed a 4-year pilot project (2013-2017) to demonstrate how satellite observations can be used to monitor large numbers of volcanoes cost-effectively, particularly in areas with scarce instrumentation and/or difficult access. The pilot aims to improve disaster risk management (DRM) by working directly with the volcano observatories that are governmentally responsible for volcano monitoring as well as with the international space agencies (ESA, CSA, ASI, DLR, JAXA, NASA, CNES). The goal is to make sure that the most useful data are collected at each volcano following the guidelines of the Santorini report that observation frequency is related to volcano activity, and to communicate the results to the local institutions in a timely fashion. Here we highlight how coordinated multi-satellite observations have been used by volcano observatories to monitor volcanoes and respond to crises. Our primary tool is measurements of ground deformation made by Interferometric Synthetic Aperture Radar (InSAR), which have been used in conjunction with other observations to determine the alert level at these volcanoes, served as an independent check on ground sensors, guided the deployment of ground instruments, and aided situational awareness. During this time period, we find 26 volcanoes deforming, including 18 of the 28 volcanoes that erupted – those eruptions without deformation were less than 2 on the VEI scale. Another 7 volcanoes were restless and the volcano observatories requested satellite observations, but no deformation was detected. We describe the lessons learned about the data products and information that are most needed by the volcano observatories in the different countries using information collected by questionnaires. We propose a practical strategy for regional to global satellite volcano monitoring for use by volcano observatories in Latin America and elsewhere to realize the vision of the Santorini report.

User oriented multidisciplinary approach to flood mapping: The experience of the Italian Civil Protection System

This paper describes two examples of synergistic management of EO based services for flood emergency monitoring. The first relates to the benefits of collaboration between decision makers, end users and experts reporting the case of the November 2014 Liguria and Po River flooding, when early activation, prior to the occurrence of the flood, was made possible and the second shows the benefits of the synergy between Sentinel-1 (S-1) and COSMO-SkyMed (CSK) contributing missions for monitoring floods at national scale. The two examples are referred to flood monitoring but the conclusions can be easily extended to other risks.