COSMO-SkyMed potential to detect and monitor Mediterranean maquis fires and regrowth: a pilot study in Capo Figari, Sardinia, Italy

Mediterranean maquis is a complex and widespread ecosystem in the region, intrinsically prone to fire. Many species have developed specific adaptation traits to cope with fire, ensuring resistance and resilience. Due to the recent changes in socio-economy and land uses, fires are more and more frequent in the urban-rural fringe and in the coastlines, both now densely populated. The detection of fires and the monitoring of vegetation regrowth is thus of primary interest for local management and for understanding the ecosystem dynamics and processes, also in the light of the recurrent droughts induced by climate change. Among the main objectives of the COSMO-SkyMed radar constellation mission there is the monitoring of environmental hazards; the very high revisiting time of this mission is optimal for post-hazard response activities. However, very few studies exploited such data for fire and vegetation monitoring. In this research, Cosmo-SkyMed is used in a Mediterranean protected area covered by maquis to detect the burnt area extension and to conduct a mid-term assessment of vegetation regrowth. The positive results obtained in this research highlight the importance of the very high-resolution continuous acquisitions and the multi-polarization information provided by COSMO-SkyMed for monitoring fire impacts on vegetation

COSMO-SKYMED: A SATELLITE TOOL FOR MONITORING CULTURAL HERITAGE

COSMO-SkyMed is the flagship Synthetic Aperture Radar (SAR) satellite constellation of the Italian Space Agency (ASI) that, among the many civilian applications for which it was originally conceived, is nowadays successfully exploited for cultural heritage applications. Current capabilities offered by both the First and Second Generations satellites are reviewed in light of the experience undertaken by ASI through data exploitation initiatives with scientific and commercial users, and more importantly in the framework of institutional projects and cooperation agreements such as those with the Colosseum Archaeological Park and the Italian Ministry of Culture (MiC). The interferometric nature of COSMO-SkyMed SAR acquisitions is the key feature exploited in structural and ground deformation monitoring of monuments and historical buildings, so as the constellation is currently the essential Earth Observation asset supporting MiC’s Extraordinary Plan of Monitoring and Conservation of Immovable Cultural Heritage. Further applications that could be enabled by COSMO-SkyMed data are explored through internal ASI research activity, such as the use of high resolution Digital Elevation Models (DEM) for topographic surveying of archaeological tells and condition assessment to estimate the impact due to natural and anthropogenic threats (e.g. looting, agriculture, destruction). Finally, current perspectives towards operational use and greater user uptake of COSMO-SkyMed for purposes of scientific downstream are opened by the new ASI programme Innovation for Downstream Preparation for Science (I4DP_SCIENCE)

Observing inland water bodies by means of X-band polarimetric SAR imagery from second generation COSMO-SkyMed constellation

This study aims at demonstrating the ability of full-polarimetric X-band synthetic arperture radar measurements provided by the COSMO-SkyMed second generation satellite constellation to extract the waterline of inland water bodies and to classify the land use/cover of the surroundings. The former task is undertaken using a state-of-the-art unsupervised method that exploits a global threshold constant false alarm rate method together with morphological filters and a Sobel edge detection algorithm; while the latter goal is pursued considering an unsupervised scattering-based approach the relies on the Wishart distribution and the eigendecomposition parameters of the coherency matrix.Experiments are carried out on satellite data set collected over the San Giuliano reservoir, in the South of Italy, where a full-polarimetric COSMO-SkyMed second generation image and a Sentinel-2 optical image are collected. Results show that the adopted methodologies allow effectively extracting the profile of the reservoir and providing classification outputs of the surroundings according to the dominant scattering mechanisms

On the extraction of the reservoirs’ waterline using polarimetric X-band SAR measurements: the case study of the San Giuliano reservoir, Italy

According to the World Bank data catalogue, (Formula presented.) records of reservoirs and their associated dams are present summing up a capacity of (Formula presented.) km3 of water. They play a crucial role in providing potable and irrigation water and, therefore, it is of paramount interest to effectively monitor such critical infrastructures. An effective approach is based on satellite remote sensing and, in particular, on the Synthetic Aperture Radar (SAR). In this paper, we critically investigate the use of polarimetric SAR measurements for reservoirs’ waterline estimation. Measurements of the novel COSMO-SkyMed Second Generation (CSG) X-band quad-polarimetric SAR related to the San Giuliano reservoir, in the South of Italy, are used to carry out an electromagnetic analysis of the different polarimetric scattering returns. Experimental results show that the cross-polarized channel, as well as the inter-channel phase, are noisy and, therefore, uninformative when used to design coherent polarimetric waterline extraction methods. From an electromagnetic viewpoint, this is due to the peculiarities of the reservoirs that call for low surface roughness and negligible wave pattern that, at once, result in a joint combination of un-tilted Bragg scattering and specular reflection. This implies that a low co-polarized backscatter and a cross-polarized signal largely below the system noise floor are to be expected. As a consequence, waterline extraction approaches that do not exploit the inter-channel phase, the so-called incoherent approaches, are shown to outperform the coherent ones

Observing intertidal coastal areas using full-polarimetric C- and X-band synthetic aperture radar measurements

This study is to analyze the multi-polarization/multi-frequency backscattering from intertidal areas using polarimetric Synthetic Aperture Radar (SAR) imagery collected by the C-band Radarsat-2 (RS2) and the X-band Cosmo-SkyMed Second Generation (CSG) satellite missions

Novel metrics for validation of PIV and CFD in IC engines

In-cylinder flow motion has a significant effect on mixture preparation and combustion. Therefore, it is vital that CFD engine simulations are capable of accurately predicting the in-cylinder velocity fields. High-speed planar Particle Image Velocimetry (PIV) experiments have been performed on a single-cylinder GDI optical engine in order to validate CFD simulations for a range of engine conditions. Novel metrics have been developed to quantify the differences between experimental and simulated velocity fields in both alignment and magnitude. The Weighted Relevance Index (WRI) is a variation of the standard Relevance Index that accounts for the local velocity magnitudes to provide a robust comparison of the alignment between two vector fields. Similarly, the Weighted Magnitude Index (WMI) quantifies the differences in the local magnitudes of the two velocity fields. The WRI and WMI are normalised and combined to produce a combined metric, the Combined Magnitude and Relevance Index (CMRI), that quantifies the differences between two flow fields in both magnitude and alignment simultaneously. PIV measurements were made every 5°ca in the central tumble plane during the induction and compression strokes. The WRI, WMI and CMRI metrics are used to validate numerical simulations of the motored in-cylinder flow measured with PIV for a range of valve lift profiles and engine speeds

ANALYSIS OF FULL-POLARIMETRIC SAR MEASUREMENTS COLLECTED IN THE INTERTIDAL AREA OF SOLWAY FIRTH BY COSMO-SKYMED 2ND GENERATION MISSION

This study is to analyze the multi-polarization backscattering from intertidal areas using polarimetric synthetic aperture radar imagery collected by the X-band Cosmo-SkyMed Second Generation satellite mission. In this study, we focus on the Solway Firth (Scotland) area that includes different habitats as wetland, salt marshes, sand dunes, and mudflats. In particular, mudflats presents a large variability of normalized radar cross section that may limit significantly the classification performance of intensity-based approaches. Within this context, for the first time, we exploit full-polarimetric Cosmo-SkyMed Second Generation imagery collected in StripMap mode

Silver-catalyzed regio- and stereoselective formal carbene Insertion into unstrained C-C σ-Bonds of 1,3-dicarbonyls

A regio- and stereoselective silver-catalyzed formal carbene insertion into 1,3-dicarbonyls has been developed, using N-nosylhydrazones as diazo surrogates. Two new C-C bonds are constructed at the carbenic carbon center through the selective cleavage of the C-C(=O) σ-bond of acyclic 1,3-dicarbonyls, enabling the preparation of various synthetically useful polysubstituted γ-diketones, γ-ketoesters, and γ-ketoamides in high yields. The in situ formation of a donor-acceptor cyclopropane, via reaction of the enolate of the 1,3-dicarbonyl with an electrophilic silver carbenoid, is proposed as a key process in the catalytic cycle

COSMO-SkyMed potential to detect and monitor Mediterranean maquis fires and regrowth: a pilot study in Capo Figari, Sardinia, Italy

Mediterranean maquis is a complex and widespread ecosystem in the region, intrinsically prone to fire. Many species have developed specific adaptation traits to cope with fire, ensuring resistance and resilience. Due to the recent changes in socio-economy and land uses, fires are more and more frequent in the urban-rural fringe and in the coastlines, both now densely populated. The detection of fires and the monitoring of vegetation regrowth is thus of primary interest for local management and for understanding the ecosystem dynamics and processes, also in the light of the recurrent droughts induced by climate change. Among the main objectives of the COSMO-SkyMed radar constellation mission there is the monitoring of environmental hazards; the very high revisiting time of this mission is optimal for post-hazard response activities. However, very few studies exploited such data for fire and vegetation monitoring. In this research, Cosmo-SkyMed is used in a Mediterranean protected area covered by maquis to detect the burnt area extension and to conduct a mid-term assessment of vegetation regrowth. The positive results obtained in this research highlight the importance of the very high-resolution continuous acquisitions and the multi-polarization information provided by COSMO-SkyMed for monitoring fire impacts on vegetation

Direct transformation of terminal alkynes into amidines by a silver-catalyzed four-component reaction

An unprecedented conversion of terminal alkynes into N-sulfonimidamides (amidines) is reported by a silver-catalyzed, one-pot, four-component reaction with TMSN3, sodium sulfinate, and sulfonyl azide. The reaction scope includes both aromatic and aliphatic alkynes. A possible cascade reaction mechanism, consisting of alkyne hydroazidation, sulfonyl radical addition, 1,3-dipolar cycloaddition by TMSN3, and retro-1,3-dipolar cycloaddition, is proposed. TMSN3 is found to play an essential role in each step of the reaction