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The method used to identify sea surface thermal features for estimating surface currents is presented. Results given have been obtained from investigations made in the Central Adriatic Sea off the coast of Monte Conero in the Marche Region, Italy, using Advanced Very High Resolution Radiometer (AVHRR) observations of NOAA-14, made simultaneously with the HF coastal radar system installed there. [ABSTRACT FROM AUTHOR]

According to the World Bank data catalogue, 6 , 862 records of reservoirs and their associated dams are present summing up a capacity of 6 , 197 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. [ABSTRACT FROM AUTHOR]

The aim of this paper is to show the feasibility of evaluating the sulphur dioxide (SO[SUB2]) flux emitted by Mt Etna volcano, using remotely sensed data of Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) in the thermal infrared (TIR). ASTER is one of the instruments on board the first Earth Observation System (EOS) satellite launched on 18 December 1999. To simulate the ASTER data, Multispectral Infrared and Visible Imaging Spectrometer (MIVIS) images, acquired during the 'Sicily '97' campaign, were used. The SO[SUB2] column abundance maps shown in this paper have been obtained by means of a simple algorithm based on the split-window technique. The parameters of the algorithm were computed using Moderate Resolution Atmospheric Radiance and Transmittance Model (MODTRAN) simulations performed with atmospheric profiles acquired during MIVIS flights. The mean SO[SUB2] flux on 12 and 16 June 1997, obtained using the ASTER simulated images,results in 42 and 33 kg s[SUP-1] respectively; these values are in good agreement with the results obtained by the inversion procedure used by Teggi et al. (1999) applied to the MIVIS data and with the Correlation Spectrometer (COSPEC) measurements performed during the campaign by other teams. [ABSTRACT FROM AUTHOR]

This paper presents a methodology capable of combining Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) imagery and ancillary data to estimate durum wheat production in Tuscany (Central Italy). First, the phenological stages of winter wheat are simulated by the use of an agro-meteorological model (Syrius 4.1). Next, MODIS NDVI images at 250 m spatial resolution are utilized to identify fields likely grown with winter wheat. The multitemporal NDVI profiles of these fields are then integrated with Syrius 4.1 outputs through a previously developed procedure in order to simulate wheat above-ground biomass and harvest index. This allows the computation of wheat yield, which, combined with relevant cropped area, provides provincial wheat production estimates. The methodology is tested using ground and MODIS data taken over four Tuscany provinces where winter wheat is widely cultivated. The accuracy of all estimated variables (wheat cropped area, yield and production) is finally evaluated against provincial statistical data. The results of this experiment indicate that the accuracy of wheat cropped area estimation and yield simulation is variable, but interannual production variations are reproduced well for all provinces. [ABSTRACT FROM AUTHOR]

This paper presents an evaluation of the nitrogen dioxide (NO2) trend inferred from UV-visible zenith-sky measurements performed at the 'Ottavio Vittori' ground-based research station (http://www.isac.cnr.it/cimone) at Monte Cimone (44.18° N, 10.7° E, 2165 m above sea level (a.s.l.)). Experimental data series are obtained from the measured spectra adopting a retrieval procedure according to differential optical absorption spectroscopy (DOAS) methodology. Data series cover the period from 1993 to 2009, with limited interruptions due to technical maintenance of the instrument or poor meteorological conditions. The NO2 trends are calculated with a linear regression model considering different factors assumed to contribute to NO2 atmospheric content. Before running the model, a procedure for data quality control was applied to reduce or exclude the influence of measurements affected by poor meteorological conditions or the vertical transport of polluted air masses from the lower troposphere. The negative trends obtained for sunrise (a.m.) and sunset (p.m.) NO2 measurements are in good agreement with previous studies accomplished for ground-based stations in the northern hemisphere. [ABSTRACT FROM AUTHOR]

Urban mapping techniques using high spectral and spatial resolution (HSSR) data were investigated. To this aim, this paper proposes a novel mean shift (MS)-based multiscale method, and different spatial approaches are compared, including differential morphological profiles (DMPs), pixel shape index (PSI), the fractal net evolution approach (FNEA), and the proposed MS method. These spatial features were computed based on a dimensionally reduced representation that was obtained using the non-negative matrix factorization (NMF) transform. The support vector machine (SVM) was then used for classification. These algorithms were evaluated using two HSSR datasets that were obtained by using the Reflective Optics System Imaging Spectrometer (ROSIS) sensor over the urban area of Pavia, northern Italy. The results show that the spatial approaches can effectively complement the spectral features for urban mapping, and the proposed MS-based multiscale algorithm can give comparable or even better results than the FNEA, DMPs and other traditional algorithms. [ABSTRACT FROM AUTHOR]

In areas with complex three-dimensional features, slope and aspect interact with light conditions and significantly affect the spatial structure of images acquired by remote sensing instruments (for example, by changing the distribution of shadows and affecting the texture of high resolution imagery). In this scenario, this paper analyses the potential and the effectiveness of an automatic classification system to identify three fundamental vegetation classes (forest, grassland and crops) in the complex topography of the Italian Alps (Autonomous Province of Trento, Italy). This classification system is based on the fusion of spectral information provided by the SPOT-5 multi-spectral channels (Ground Instantaneous Field of View, GIFOV, equal to 10 m) and textural information extracted from airborne digital orthophotos (GIFOV equal to 1 m) and is designed to be user-friendly. The texture of the digital orthophotos was modelled using defined bidirectional variograms, thereby extracting additional information unavailable in first-order texture analyses. Using SPOT-5 multi-spectral information alone, the classification accuracy in the investigated alpine area was equal to 87.5%, but increased to 92.1% when texture information was included. In particular, the texture information significantly increased the classification accuracy for crops (from 68.9% to 87.9%), especially orchards that tend to be classified as lowland deciduous forests, and herbaceous crops (such as maize) that are often misclassified as grasslands. A further simple majority analysis increased the ability of detecting grassland, crops and urban zones. The combination of the majority analysis and the proposed automatic classification system seems an effective approach to classifying vegetation types in highly fragmented and complex Alpine landscapes on a regional scale. [ABSTRACT FROM AUTHOR]

This paper describes a Synthetic Aperture Radar sea surface waves simulator, based on the velocity bunching theory and developed in the Matlab® programming language. The software has been designed and implemented for educational use. The present version of this software is run in classes at National Oceanographic Centre of Southampton, UK and at the Universita di Napoli Parthenope, Italy. [ABSTRACT FROM AUTHOR]

This paper deals with terrestrial long-range laser scanner applications, gives an overview of topics related to this methodology, provides real and tested information about laser scanners, and analyses the reflectance of different materials. After positive results obtained during an experimental test executed in Bologna (Italy) on March 2005, the INGV (Bologna, Italy) and CODEVINTEC srl (Milan, Italy) planned a mission over the Mount Vesuvius volcano (Naples, Italy). For the first time, a wide crater area composed of low reflectivity materials was completely surveyed, creating a very accurate digital surface model. In this work, a long-range laser scanner was used to create high-precision surveys that demonstrated very low residual values in scan comparisons. The results lead to the conclusion that this methodology is suitable for surface monitoring proposals. [ABSTRACT FROM AUTHOR]

This paper concerns the time variation in mean sea surface temperature measurements on a regional scale by using AVHRR data. The studied algorithm uses sub‐pixel resolution, precise geolocation and determination of the cloudy pixels. In order to indicate cloudy pixels, thresholds based on regional temperature maps are applied instead of the average temperatures of the Mediterranean Sea. Special calculations have been made for coastline pixels. The zone considered is the sea off the Tuscan region of Italy. [ABSTRACT FROM AUTHOR]

In recent years, SAR interferometry has become one of the most popular emerging techniques for the assessment of ground displacements, and, as such, it is of great interest as a possible operational tool for civil protection institutions having to deal with landslide risk. The paper presents some of the results obtained in northern Italy during a research project aimed at testing the potentiality of the application of C‐band space‐borne interferometry and Ku‐band ground based interferometry during different specific civil protection activities. Main research objectives were the detection of the movements of complex earth and rock slides affecting built‐up areas during the 1990s, and the near real‐time monitoring of a reactivated rotational earth slide over an emergency period of 15 days. Results of space‐borne interferometry did qualitatively fit with the geological interpretation of the mass movements and with ground truths such as damaged buildings and in situ monitoring systems. However, this was not achieved in quantitative terms, suggesting that this technique should be used limitedly for displacement recognition and not monitoring. On the other hand, ground‐based interferometry proved valuable both for a qualitative and a quantitative estimate of slope movements. Nonetheless, the research has also enabled the limitations that are still to be tackled in order to bring these systems to an operational usage in civil protection to be highlighted. [ABSTRACT FROM AUTHOR]

This paper discusses the preprocessing, clustering, and labelling steps of data supplied from NOAA Advanced Very High Radiometers (AVHRR) to monitor vegetation phenology in a complex area (Vulture Basin, Italy). Time cluster maps of Normalized Difference Vegetation Index (NDVI) are compared with a land use map and a Digital Elevation Model of the region. This study results show that AVHRR/NDVI well discriminates forested areas whatever the altitude may be; whereas the phenology of cultivated fields must be distinguished between plain and mountain phenology. The pixels not fitting into this picture mostly account for three peculiar microclimatic situations (two long and narrow valleys and a smooth, sunny mountain area). [ABSTRACT FROM AUTHOR]

This paper describes a synergetic use of satellite radar images and ancillary information to detect flooded areas at their peak and evaluates its potential with mapping. The procedure was tested on the catastrophic flood that occurred in Regione Piemonte in Italy in November 1994. Two ERS-1 synthetic aperture radar (SAR) images were processed, one acquired one month before the flood and the other acquired three days after the event. Visual interpretation and two different thresholding techniques were performed. The flood map derived shows only a small fraction (20%) of the actually flooded lands because of the time delay between the flood peak and the satellite overpass. To overcome this limitation, the authors developed a new procedure to estimate the flooded area at the peak time by integrating the flooded area from SAR imagery with digital topographic data from a GIS technique. This method allowed inundated areas covering 96.7% of the flooded area officially recorded by the local government to be mapped. The proposed procedure is suitable for mapping flooded areas even when satellite data are acquired some days after the event, thus overcoming the constraint of temporal resolution in the application of SAR imagery in hydrology. [ABSTRACT FROM AUTHOR]

Multi-frequency and multi-temporal polarimetric SAR measurements, carried out during SIR-C/X-SAR missions over the Montespertoli area have been analysed and compared with data collected at the same frequency and polarization, but at different dates, with the NASA/JPL AIRSAR. This paper presents an analysis of the achieved results aiming at evaluating the contribution of SAR data for estimating some geophysical parameters which play a significant role in hydrological processes and in particular soil moisture and roughness. The study has pointed out that in the scale of surface roughness typical of agricultural areas, a co-polar L-bandsensor gives the highest information content for estimating soil moisture and surface roughness. The sensitivity to soil moisture and surface roughness for individual fields is rather low since both parameters affect the radar signal. However, considering data collected at different dates and averaged over a relatively wide area that includes several fields, the correlation to soil moisture is significant, since the effects of spatial roughness variations are smoothed. On the other hand the sensitivity to surface roughness is better manifested at a spatial scale, integrating on time to reduce the effects of moisture variation. The retrieval of both soil moisture and surface roughness has been performed with good results by means of a semi-empirical model. [ABSTRACT FROM AUTHOR]

In this paper we demonstrate SAR system capability for detecting and characterizing marine surface slicks. During an aircraft measurement campaign over the Gulf of Genoa (Italy), a multi-frequency SAR system, operating in P-, L- and C-bands, explored a sea area heavily covered by slicks. At the same time in situ measurements were performed with an interferential microwave probe, installed on board a small boat, capable of measuring high resolution sea spectra up to frequencies of capillary waves. By plotting SAR pixel intensity versus sea wave Bragg frequency we obtained wide portions of the sea spectrum region affected by the surface film damping. Spectra derived from SAR imagery and from gauge data present comparable slopes and furthermore the ratio between clean to slicked water spectrum obtained with the two techniques were surprisingly similar. This demonstrates the multi-frequency SAR systems ability to detect and characterize sea surface films assuming the Bragg mechanism in the radar backscatter. The outlined analysis suggests a simple methodology to monitor coastal water quality by using airborne SAR. [ABSTRACT FROM AUTHOR]