Remocean System for the Detection of the Reflected ... - IEEE Xplore

IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING, VOL. 7, NO. 7, JULY 2014

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Remocean System for the Detection of the Reflected Waves from the Costa Concordia Ship Wreck Giovanni Ludeno, Carlo Brandini, Claudio Lugni, Daniele Arturi, Antonio Natale, Francesco Soldovieri, Bernardo Gozzini, and Francesco Serafino

Abstract—This paper presents the validation of the Remocean X-band wave radar as a tool for sea state monitoring in coastal zones, by processing the data collected and processed by the radar platform installed at the port of Giglio Island. In particular, the effectiveness of the sea wave height reconstruction has been tested during the storm on November 27, 2012, by focusing on the analysis of the spectral slope and the statistical properties of the ocean waves. A further proof of the effectiveness of the system has been shown by comparing both the estimated sea state parameters and 2-D directional spectrum with the benchmark forecasting models WaveWatchIII (WW3) and Simulating Wave Nearshore (SWAN). Index Terms—Marine X-band radar, sea state monitoring.

I. INTRODUCTION

T

HE DEPLOYMENT of X-band radar systems for sea state monitoring is of significant interest since this kind of systems enable sea state monitoring with a high spatial resolution (of the order of meters) in a range of few kilometers from the observation platform. Due to their low cost and easiness of installation together with their operative flexibility, X-band radars are especially suitable to scan the sea surface with high temporal rate, by exploiting fixed and/or moving observation platforms for ship navigation support and coastal areas monitoring purposes [1]–[3]. In this context, the more recent research efforts have been focused on the development of novel data processing procedure, based on the use of the normalized scalar product (NSP) method, for the reconstruction of the directional spectrum in nonhomogenous areas in coastal zone. This technique has been validated in several challenging cases, as for the Remocean system [4]–[6]. In particular, by

Manuscript received December 04, 2013; revised February 17, 2014; accepted April 17, 2014. Date of publication June 19, 2014; date of current version August 21, 2014. G. Ludeno, D. Arturi, A. Natale, F. Soldovieri, and F. Serafino are with the Institute for Electromagnetic Sensing of the Environment, National Research Council, Napoli I-80124, Italy (e-mail: serafi[email protected]; [email protected]. it; [email protected]). G. Ludeno is with the Second University of Naples, Department of the Industrial and Information Engineering, Aversa (Ce), 81031, Italy (e-mail: [email protected]). C. Brandini and B. Gozzini are with CNR-IBIMET, Biometeorology Institute, and LaMMA Consortium, Firenze I-50145, Italy (e-mail: [email protected]. toscana.it; [email protected]). C. Lugni is with the Institute of Marine Technology, National Research Council, INSEAN, 00128 Roma, Italy (e-mail: [email protected]). D. Arturi is with the Information Engineering Department, University “Mediterranea” of Reggio Calabria, Reggio Calabria 89124, Italy (e-mail: [email protected]). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/JSTARS.2014.2321048

considering the sea state monitoring in coastal areas, the performance of the Remocean system has been already assessed in [4] where the sea surface currents estimated by the NSP method have been compared with the measurements provided by a HF radar system, and in [5] where the bathymetry estimation provided by the NSP method has been compared with the ground truth measurements provided by the multibeam echo-sounder. In this study, we present the results achieved by exploiting the technique described in [5] for the bathymetry estimation and sea wave height reconstruction in coastal areas. It is worth noting that the X-band radar data processing is challenging in coastal areas, due to the high variability of the sea surface current and bathymetry, which makes the assumption of spatial homogeneity of the data unfeasible. Under this hypothesis of nonhomogeneity, it is not possible to use the data processing techniques usually adopted for deep water; thus, in order to overcome this drawback, here we exploit a novel technique [5], which use an enhanced version of the NSP, with the aim to make a local analysis of the sea surface current and bathymetry. As demonstrated in [7], the NSP technique allows at obtaining more accurate and robust estimations, so that the local analysis is improved. In this paper, by adopting the enhanced version of NSP, we analyzed the sea wave height in the Giglio Island port, where the Costa Concordia ship wreck is located. The presence of the wreck makes this area of high interest for scientific and applicative purposes, since the Remocean wave radar measurements, exploiting the above said data processing techniques, allowed at optimizing the design of the infrastructure deployed for the wreck recover. Costa Concordia cruise ship, with about 4200 passengers onboard, smashed its hull on 13th of January 2012 against the coast of Giglio Island, a tiny piece of land in the Tuscan Archipelago located in the Northwestern Mediterranean Sea (see Fig. 1). The state of emergency was declared to face the crisis and a number of different devices were installed on the island to monitor the ship wreck and to prevent oil spills in the sea. The Remocean system was installed at the Giglio Island by the LaMMA Consortium as a supporting observational tool providing information about the sea state, which was important for the removal operations of the Costa Concordia ship wreck. The radar data have been collected during the storm of November 27, 2012 by the system installed at the Giglio Island (Tuscany, Italy). The operational environment at Giglio Island is very challenging for the X-band radar system, due to the fact that we are very close to the coast and for the presence of the wreck, which arose sea state phenomena not easily predictable by the current provisional models.

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Fig. 1. Tuscan Archipelago located in the Northwestern Mediterranean Sea. The red circle indicated the Giglio Island.

Anyway, the presence of the Costa Concordia allowed us to make a performance analysis of the X-band wave radar for the observation of phenomena rarely detectable in coastal zones. In particular, here, we focus on the 3-D (space-time) reconstruction of the sea surface in order to show the capability of the system to detect and characterize the waves reflected by the shipwreck. The analysis of these data is based on the evaluation of the spectral slope and the statistical properties of the sea waves with the aim of establishing if the X-band radar sea state estimation is consistent with the physical evolution of the sea wave reflected by the wreck. Furthermore, the reliability of the estimated sea state parameters, as the direction and the period T of the dominant wave, has been tested through a comparison with the direct measurements provided by a buoy located close to the ship wreck. This paper is organized as follows. Section II gives a brief description of the data processing, whereas the details of the measurement campaign are provided in Section III. Section IV is devoted at presenting and analyzing the results provided by the Remocean system in terms of wave height reconstruction, whereas the comparison of the sea state parameters estimation with the measurement provided by the buoy and the forecasting model are presented in Section V. Finally, conclusion follows. II. DATA PROCESSING The sea state reconstruction from X-band radar images can be stated as an inverse problem and provides parameters, such as wave direction, wavelength, period of dominant waves, significant wave height, sea surface current intensity and direction, and temporal-spatial evolution of the waves elevation (more details about the inversion approach can be found in [8] and [9]). The

usual inversion procedure cannot applied to X-band radar images acquired in coastal zone, where there are nonuniform values of the surface currents and bathymetry and to reconstruction the global wave spectrum we have developed a new strategy. The solution strategy to solve this linear inverse problem is schematized by the block diagram in Fig. 2 The block diagram can to be summarized as follows. As a first step, the raw X-band radar image sequence is subdivided in subareas whose extent is dictated by a tradeoff between the necessity to assume the sea surface current and bathymetry constant in such subareas (pushing to a narrowing of the subarea) and the necessity to achieve a reliable spectral analysis (pushing to the enlargement of the subarea). As a second step, the sub area radar image sequence is transformed into 3-D image spectrum by means of a 3-D-Fast Fourier Transform (3D-FFT); after, the effect of the received signal power decay along the range direction, which has a smaller variability compared with the one associated to the phase of the signal, is filtered by applying a high-pass (HP) filter; the resulting signal is the image spectrum [10], [11]. The third step aims at extracting the linear gravity wave components from the image spectrum . This filtering exploits the dispersion relation relating the wavenumber to the angular frequency through the sea surface current and the water depth . The dispersion relation is given by

where is the acceleration due to the gravity at the earth’s surface . and

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Fig. 3. Installation site of the Remocean system indicated by the red circle.

MEASUREMENT PARAMETERS

TABLE I REMOCEAN SYSTEM DURING

OF THE

THE

STORM

Fig. 2. Block diagram of the inversion procedure.

Note that the estimation of the current vector and water depth are needed to apply reliably the dispersion relation in the filtering step [12]. In this frame, here, we exploit a recently proposed approach for the surface current and depth estimation, which is based on the maximization of the NSP, [8]

is the amplitude of the image spectrum, is a characteristic function accounting for the support of the dispersion relation (1), and are the square amplitude of the image spectrum and , respectively. This technique has been shown to have better performance compared with the least square approach presented [7], [13] as regards the accuracy of the estimation. Once, the current and bathymetry have been estimated, the fourth step consists in reassembling the spectra in order to obtain a spectrum able to account for the sea surface current contributions estimated for each subarea (see the merging block in Fig. 2). The Band-Pass (BP) filter is built on the basis of the dispersion relation defined in (1) and then applied to the image spectrum ; the result of the filtering is the function . The fifth step aims at turning from the filtered radar image spectrum to the desired sea wave spectrum . This step requires the knowledge of the radar modulation transfer function (MTF), which accounts for the specific modalities of the electromagnetic sensing phenomenon. It is worth to stress that in this study case, we employ a MTF different from the one commonly adopted in literature [11]. More details on the evaluation of MTF here employed will be presented in Section IV. Finally, the knowledge of the wave spectrum allows determining the main sea state parameters; this is where

performed by generating the wave number directional spectrum , whose maximum provides the wavelength , the direction and period of the dominant wave. The last step aims at providing the time-spatial evolution of the wave height by performing an Inverse FFT (3D-IFFT) of the spectrum function . III. MEASUREMENT CAMPAIGN This section is devoted at describing the instrumentation and the measurement campaign carried during the storm on November 27, 2012. A CONSILIUM X-band radar radiating a maximum power of 25 kW and equipped with an 9 feet (2.74 m) long antenna was deployed. The radar antenna is located at the coordinates: ; . The antenna is installed on a lighting pylon at a height of 15 m above sea level (see Fig. 3). The data were collected on November 27, 2012 during a storm and the details of the acquisition parameters are given in Table I. Fig. 4 depicts a radar image collected during the storm, where it is possible to observe the sea wave pattern, the location of the radar indicated by the red triangle and the position of the Costa Concordia ship wreck as indicated by the red arrow.

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Fig. 4. Radar image collected during the storm. The position of the radar and the ship wreck is indicated by the red triangle and the red arrow, respectively.

Fig. 5. Sea wave height reconstruction provided by the Remocean system. The yellow arrow indicates the direction of the dominant wave mode, and the green arrow indicates the direction of the secondary wave mode.

IV. ANALYSIS OF THE SEA STATE RECONSTRUCTION The spectral slope and the statistical properties of the ocean waves have been evaluated, in order to establish if the sea state reconstruction provided by the Remocean system, has a physical meaning from the hydrodynamics point of view.

Fig. 6. Log–Log normalized 1-D-spectrum as function of the wavenumber (green solid line) in open sea. The power law curves , , , and the MTF function are also reported.

Fig. 5 depicts a spatial map of the sea wave height collected during the storm, where it is possible to note the presence of two different wave modes: 1) the dominant mode, coming from South-East, indicated by the yellow arrow; 2) wave mode, coming from South-West, is indicated by the green arrow. In particular, this spatial map has been obtained by the data processing of collected on November 27, 2012 at about 12:00 am (UTC). The spectral slope and the statistical properties of the ocean waves have been the subject of several research investigations, since the pioneering study of Phillips [14]. Based on a simple dimensional analysis, he concluded that in the equilibrium range, the wave spectrum of the ocean waves varies proportionally to . In his investigation, Phillips assumed the wind effects negligible on the limiting configurations of the waves and then on the wave spectrum within the inertial range. Using the “weak-turbulence theory,” Zakharov and Filonenko [15] demonstrated the existence of an analytical solution for the kinetic equation where the nonlinear interactions induce a frequency spectrum proportional to , i.e., to for the wavenumbers spectrum (assuming the relation dispersion for deep water, where is assumed). This theory was further confirmed by the theoretical study of Phillips [16]. However, the wave spectrum depends on several parameters that need to be fitted in the spectrum, among them: fetch, duration of wind blowing, existence of a swell. Full scale measurements of the ocean waves demonstrated as the exponent of the frequency power law of the wave amplitude spectrum is strongly varying, although most of them confirmed a scaling, in accordance with the weak-turbulence theory [17], [18]. In the following, wave radar measurements are used to estimate the power law for the wavenumber spectrum. Starting from

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Fig. 7. Log–Log normalized 1-D-spectrum as function of the wavenumber (green solid line) in open sea. The power law curves function (6) and (7) are also reported in (a) and (b), respectively.

the 3-D spectrum is obtained as

, the 2-D wavenumber spectrum

,

,

, and the MTF

case the MTF used is the one proposed by Nieto [11] and worldwide used in the practical applications < >

where ( and N defined in Table I). After, the wavenumber spectrum is transformed in polar coordinates as and the 1-D omnidirectional spectrum is calculated as

The use of this MTF function is not able to provide accurate estimation of the spectral slope, as shown by Fig. 6. With the aim to best fit the power law of the weak turbulence theory, for data in open sea, two different MTFs have been tested for the case of the Roma cruise ship. The two MTF functions are reported as follows:
< > The related 1-D-spectra are reported in Fig. 7. For the case of Roma cruise ship, the MTF of (7) well reproduces the weak turbulence behavior in the equilibrium range, here identified for < < . A similar MTF < has been used here to identify the wave measurement in front of Giglio Island (coastal region). The related 1-D omnidirectional spectrum is reported in Fig. 8.

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Fig. 8. Log–Log normalized 1-D-spectrum as function of the wavenumber k (green solid line). The power law curves , , , and the adopted MTF function are also reported.

V. COMPARISON AND RESULTS This section is devoted at presenting and comparing the results provided by Remocean system in terms of sea state parameters estimation, thanks to the inverse scheme described in Section II, where the MTF the one exploited is the one given by in (8). Starting from 2-D wavenumber spectrum , it is possible to determine the characteristic sea state parameters in terms of wavelength, wave direction, wave period of the dominant wave. Fig. 9(a) depicts the directional spectrum obtained by the dataset collected on November 27, 2012 at about 12:00 am (UTC); the directional spectrum exhibits two spectral modes: the dominant one and a secondary mode associated to the sea waves reflected by the Costa Concordia wreck (see the red arrow in Fig. 5). The reliability of the results of the Remocean system has been tested by a comparison with different the measurements of a buoy located in the vicinity of the wreck. As a further proof of the reliably of the Remocean results, the outcomes of the Remocean analysis have been compared with the ones of the provided by an operational forecasting system available at the LaMMA Consortium, which are based on the WaveWatch III (WW3) [19] and Simulating Wave Nearshore (SWAN) [20] models and do not account the presence for the Costa Concordia wreck.

Both models are able to simulate main wave generation, propagation, and dissipation phenomena such as wind-wave generation, nonlinear wave-wave interactions, dissipation due to bottom friction, large scale propagation, and breaking. These two models had different behaviors: WW3—in the philosophy of the WAM (Wave Model) is a model best suited to describe the propagation of waves at oceanic scales, SWAN is a model best suited to describe waves behaviors in near-shore areas. Nowadays, WW3 and SWAN share much in common with regard to physical aspects, but WW3 is still more suitable to deal with wave generation/propagation on large scales, whereas SWAN is numerically more efficient (due to implicit integration schemes), to solve the basic equations for wave action balance at higher resolution (well below 1 km) [20]. For the forecasting system in use at the LaMMA Consortium, a SWAN model at 600 m resolution is embedded onto a WW3 model implemented over a wide area covering all the Tyrrhenian Sea at about 3 km resolution. The details of the bathymetry and the coast at such resolutions are quite different, so only with the higher resolution model it is possible to evaluate the effects of wave refraction. Notice that phase-averaged wave models such as WW3 and SWAN are not able to represent back-scattered waves neither reflected waves. Fig. 9 shows how the spectrum detected by the wave radar is consistent with the one representing a dominant wave from South-East calculated by models. The waves reflected by the ship, with a peak specular with respect to the direction of dominant wave and with the same wavelength, can obviously be represented by such phase-averaged wave. The evaluation of such a reflection has shown to be very important for wreck removal activities, as it allows us to calibrate specific phaseresolving models. Finally, Table II provides the comparison among the Remocean, WW3, and SWAN results and the ground truth obtained by the buoy measurements for the dominant sea wave impinging on the wreck. Moreover, we also provide the estimation results which can be obtained by exploiting the MTF commonly used in literature [11]. As can be seen in Table II, the estimates of the period and direction obtained from the Remocean system are very similar to the direct measurement provided by the buoy with the difference of a few degrees regarding the direction of the wave.

VI. CONCLUSION This paper has shown the effectiveness of the Remocean system for the sea state monitoring in coastal zones based on the radar observations at Giglio Island, where Remocean system is deployed as an “observational” tool for a support to the Costa Concordia wreck removal operations. In particular, the presence of an “artificial” obstacle as the Costa Concordia has permitted to show the reliability of the Remocean system in order to detect and characterize the phenomenon of the reflection of the sea waves (associated to the dominant mode) impinging on the wreck. The good performance of the Remocean system in the reconstruction/monitoring of the sea dominant mode has been assessed by the comparison with the

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Fig. 9. Directional spectrum obtained by Remocean system (a) and forecast model [WW3 and SWAN (b) and (c), respectively].

COMPARISON BETWEEN

THE

TABLE II BUOY, REMOCEAN, INVERSION WITH NIETO MTF, WW3 MODEL

ground truth measurements provided by a buoy, and estimated wave spectra were also compared with model results. The Remocean system allows a more reliable characterization of the sea dominant mode with respect to the models. Furthermore, X-band radar system allows at detecting and characterizing the secondary mode arising by the reflection of the sea waves by the wreck. These secondary modes are not accounted for by the presently available models used for the operational forecasting activities at Giglio Island.

REFERENCES [1] R. Young, W. Rosenthal, and F. Ziemer, “Three-dimensional analysis of marine radar images for the determination of ocean wave directionality and surface currents,” J. Geophys. Res., vol. 90, pp. 1049–1059, 1985. [2] F. Ziemer and W. Rosenthal, “Directional spectra from shipboard navigation radar during LEWEX,” in Directional Ocean Wave Spectra: Measuring, Modeling, Predicting, and Applying, R. C. Beal, Ed. Baltimore, MD, USA: The Johns Hopkins Univ. Press, 1991, pp. 125–127. [3] W. J. Plant and W. C. Keller, “Evidence of Bragg scattering in microwave Doppler spectra of sea return,” J. Geophys. Res., vol. 95, pp. 16299–16310, 1990. [4] F. Serafino et al., “REMOCEAN: A flexible X-band radar system for seastate monitoring and surface current estimation,” IEEE Geosci. Remote Sens. Lett., vol. 9, no. 5, pp 822–826, Sep. 2012. [5] G. Ludeno, S. Flampouris, C. Lugni, F. Soldovieri, and F. Serafino, “A novel approach based on marine radar data analysis for high resolution bathymetry map generation,” IEEE Geosci. Remote Sens. Lett., vol. 11, no. 1, pp. 234–238, Jan. 2014. [6] G. Ludeno et al., “X-band marine radar system for high speed navigation purposes: A test case on a cruise ship,” IEEE Geosci. Remote Sens. Lett., vol. 11, no. 1, pp. 244–248, Jan. 2014. [7] W. Huang and E. Gill, “Surface current measurement under low sea state using dual polarized X-band nautical radar,” IEEE J. Sel. Topics Appl. Earth Observ. Remote Sens., vol. 5, no. 6, pp. 1868–1873, Dec. 2012. [8] F. Serafino, C. Lugni, and F. Soldovieri, “A novel strategy for the surface current determination from marine X-Band radar data,” IEEE Geosci. Remote Sens. Lett., vol. 7, no. 2, pp. 231–235, Apr. 2010. [9] F. Serafino, C. Lugni, J. C. Nieto Borge, V. Zamparelli, and F. Soldovieri, “Bathymetry determination via X-band radar data: A new strategy and numerical results,” Sensors, vol. 10, no. 7, pp. 6522–6534, Jul. 2010.

AND

SWAN RESULTS

[10] I. R. Young, W. Rosental, and F. Zeimer, “A three-dimensional analysis of marine radar images for the determination of ocean wave directionality and surface currents,” J. Geophys. Res., vol. 90, pp. 1049–1059, 1985. [11] J. C. Nieto Borge, R. G. Rodriguez, K. Hessner, and I. P. Gonzales, “Inversion of marine radar images for surface wave analysis,” J. Atmos. Ocean. Technol., vol. 21, pp. 1291–1300, 2004. [12] J. C. Nieto Borge and C. GuedesSoares, “Analysis of directional wave fields using X-band navigation radar,” Coastal Eng., vol. 40, pp. 375–391, 2000. [13] J. C. Nieto Borge, “Analisis de Campos de OleajeMediante Radar de Navegacion en Banda X-,” Ph.D. dissertation, Dept. Physics, Universidad de Alcalá, Madrid, Spain, 1997. [14] O. M. Phillips, “On some properties of the spectrum of wind-generated ocean waves,” J. Mar. Res., vol. 16, pp. 231–240, 1958. [15] V. E. Zakharov and N. Filonenko, “Energy spectrum for stochastic oscillations of the surface of a liquid,” Soviet Phys. Dokl., vol. 11, 1967. [16] O. M. Phillips, “Spectral and statistical properties of the equilibrium range in wind-generated gravity waves,” J. Fluid Mech., vol. 156, pp. 505–531, 1985. [17] Y. Toba “Local balance in the air-sea boundary processes. III. On the spectrum of wind waves,” J. Oceanogr. Soc. Japan, vol. 29, pp. 209–220, 1973. [18] K. K. Kahma, “A study of the growth of the wave spectrum with fetch,” J. Phys. Oceanogr., vol. 11, p. 1503, 1981. [19] H. L. Tolman. (2009). User Manual and System Documentation of WAVEWATCH III version 3.14. NOAA NWS NCEP MMAB Technical Note 276 [Online]. Available: polar.ncep.noaa.gov/waves/wavewatch/wavewatch. shtml [20] R. C. Ris, L. H. Holthuijsen, and N. Booij, “A third-generation wave model for coastal regions,” J. Geophys. Res., vol. 104, no. C4, pp. 7667–7681, Apr. 15, 1999. Giovanni Ludeno was born in Caserta, Italy, on January 28, 1984. He received the Master’s degree in telecommunication engineering from the University “Mediterranea” of Reggio Calabria, Reggio Calabria, Italy, in 2011, and is working toward the Ph.D. degree at the Second University of Naples, Caserta, Italy, in 2012. From November 2011 to October 2012, he was on scholarship with the Institute for Electromagnetic Sensing of the Environment (IREA) CNR of Naples, Naples, Italy. From October 2012 to February 2014, he was a Research Fellow with the company Vitrociset SpA, Roma, Italy, dealing with the analysis of X-band radar data for the detection of reflective targets on the sea surface, carrying out this activity at the IREA-CNR in Naples. Currently he is a Research Fellow with the IREA-CNR. His research interests include remote sensing with special regard to the development of innovative strategies for the estimation of sea state parameters, surface currents, and bathymetry through high resolution nautical X-band radar data.

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Daniele Arturi was born in Reggio Calabria, in 1986. He received the Master’s degree in telecommunications engineering from the University of studies “Mediterranea” of Reggio Calabria in collaboration with the IREA-CNR of Naples, Naples, Italy, and is currently pursuing the Ph.D. degree in telecommunications engineering at the same university, always in collaboration with the IREA-CNR of Naples. From September 2011 to September 2012, he worked as a Consulent in Accenture S.p.A., Milan, Italy, mainly on activities related to telecommunications world. Currently, he is working as a Consulent in Vitrociset S.p.A., Roma, Italy, for PON-01936 HABITAT project dealing with these topics and with the development of a prototype for the harbor security. Antonio Natale was born in Naples, Italy, on July 3, 1982. He received the B.S. and M.S. degrees (cum laude) in telecommunication engineering from the University of Naples Federico II, Napoli, Italy, in 2005 and 2008, respectively, and received the Ph.D. degree from the University of Naples Federico II, in 2012. In 2011, he was as a Visiting Student with the Surrey Space Centre (SSC), University of Surrey, Surrey, U.K. In that period, he was the Principal Researcher for the project “Applications for S-band SAR” funded by EADS Astrium Ltd, SSC. Since April 2012, he has been with the Istituto per il Rilevamento Elettromagnetico dell’Ambiente (IREA), Italian National Research Council (CNR), Naples, Italy. In 2013, he spent a period at the NATO-CMRE (Centre for Maritime Research and Experimentation, La Spezia, Italy as a visiting scientist to develop strategies for target detection and tracking from high resolution incoherent radar data. His research interests include remote sensing, with special regard to modeling of electromagnetic scattering from natural surfaces, as well as simulation and processing of synthetic aperture radar (SAR) signals, development of techniques for both the retrieval of sea state parameters, and the target detection via marine radar data. Dr. Natale was awarded the IEEE GRS South-Italy Chapter prize in 2009 for the best Italian thesis in remote sensing discussed in 2008 and, moreover, he received the “2009 S. A. Schelkunoff Transactions Prize Paper Award” from the IEEE Antennas and Propagation Society for the best paper published in 2008 in the IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION. Francesco Serafino graduated in electronic engineering from the University of Reggio Calabria, Reggio Calabria, Italy, in 2000, and received the International Ph.D. degree in information and communication technologies from the University Federico II of Naples, Naples, Italy, in collaboration with the Delft Institute for Earth–Oriental Space Research (DEOS), in 2005. Since September 2007, is a Researcher with CNR IREA, where for over 10 years has been dedicated to the Synthetic Aperture Radar (SAR) image processing, differential SAR interferometry, and 3-D and 4-D SAR tomography. His research interests include the extraction of hydrodynamic parameters from the analysis of X-band radar images with particular reference to the estimation of surface currents and the reconstruction of bathymetry maps. Dr. Serafino has been a Reviewer for the most prestigious scientific journals and international conferences in its field and inventor of two European patents and the author of over 60 publications in prestigious international journals and conferences. Bernardo Gozzini received the degree in agricultural science. He is a Research Scientist at IBIMET-CNR with experience in biometeorology and meteorology/ modelling application. Mr. Gozzini is a Sole Director at LaMMA Consortium (Environmental Modelling and Monitoring Laboratory for Sustainable Development). The main sectors in which the LaMMA Consortium specializes are meteorology, climatology, geographic information systems (GIS), and geology.

Carlo Brandini received the Ph.D. degree in hydrodynamic engineering from the University of Padua, Padua, Italy, in 2001. He is a Researcher at IBIMET-CNR and he is contributing since 2001 to the activities of the LaMMA Consortium in which he serves as responsible for Oceanography activities. His interests include extreme waves dynamics, and regional/coastal oceanography aspects, with a main experience on numerical models for waves propagation, ocean circulation modeling and biogeochemical implications, the design of advanced marine monitoring systems both on a regional and national level, and through the participation to national and international initiatives. Claudio Lugni graduated in aeronautical engineering, and received the Ph.D. degree in theoretical and applied mechanics from the University of Rome, Rome, Italy. He is a Senior Researcher at CNR-INSEAN, Roma, Italy, and Adjunct Professor in Marine Hydrodynamics at NTNU, Centre of Excellence AMOS, Norway. He is a Director of the INSEAN-Department ‘Seakeeping and Maneuvering’ from 2008 to 2010. He managed 5 international research projects and partecipated to several Italian and European Research Project. His research interests include concerned the theoretical, numerical, and experimental studies of the violent hydrodynamic phenomena involved in the wave-structure interactions, the unsteady evolution of nonlinear free-surface flows (wave propagation, wave-breaking, sloshing), wave-structure interaction (wave impact, slamming, water-on-deck, hydroelasticity), ship motion (seakeeping), ship maneuvering (maneuverability), and renewable energy (wind offshore turbine) and also sloshing flows, water-on deck, slamming, and hydroelastic interactions. He is an author/coauthor of over 90 peer reviewed papers, of which 35 on ISI-Scopus International Journals. Dr. Lugni is a member of the International Towing Tank Conference (ITTC) from 2002 to 2003. In 2003, he was a Visiting Scientist with the Centre of Excellence on Ships and Ocean Structures (CeSOS), Trondheim, Norway, and presently ongoing within the new borne Centre for Autonomous Marine Operations and Systems (AMOS), Trondheim, Norway. Francesco Soldovieri (M’10) received the Laurea degree in electronics engineering from the University of Salerno, Salerno, Italy, in 1992, and the Ph.D. degree in electronics engineering from the University of Naples “Federico II,” Naples, Italy, in 1996. In 1993, he joined the Electromagnetic Research Group, University of Naples; and in 1998–1999, he held a Postdoctoral Fellowship with the same university. In 2001, he joined as a Researcher with the Institute for Electromagnetic Sensing of the Environment, Italian National Research Council (IREACNR), Naples, Italy, where he has been a Senior Researcher since 2006. His research interests include electromagnetic diagnostics, inverse scattering, GPR applications, antenna diagnostics and characterization, and security applications. Dr. Soldovieri was the General Chair of the International Workshop on Advanced Ground Penetrating Radar 2007. Since 2002, he has been involved in the Technical Committees of the GPR Conference and IWAGPR Workshop. He has been a Special Guest Editor for Issues on the Journal of Applied Geophysics, Near Surface Geophysics, and Advances in Geosciences. He was awarded the 1999 Honorable Mention for the H.A. Wheeler Applications Prize Paper Award of the IEEE Antennas and Propagation Society.