Protocols for UAS-based observation

In Chapter 1 the terms and the characteristics of an unmanned spatial data collection system were defined along with the fields of application, advantages, and disadvantages of different solutions and sensors. This chapter will present an overview of existing protocols and broad guidelines on environmental unmanned aerial system (UAS)-based monitoring, including study design with the general and possible use of the platform and sensor/camera settings, comprising quality assurance (QA) with all necessary steps (i.e., georeferencing, radiometric calibration for optical and thermal sensors, programming the flight mission, and data processing) to fulfill a complete survey mission for a given en…

Critical analysis of the thermal inertia approach to map soil water content under sparse vegetation and changeable sky conditions

The paper reports a critical analysis of the thermal inertia approach to map surface soil water content on bare and sparsely vegetated soils by means of remotely sensed data. The study area is an experimental area located in Barrax (Spain). Field data were acquired within the Barrax 2011 research project. AHS airborne images including VIS/NIR and TIR bands were acquired both day and night time by the INTA (Instituto Nacional de Tecnica Aeroespacial) between the 11 th and 13 rd of June 2011. Images cover a corn pivot surrounded by bare soil, where a set of in situ data have been collected previously and simultaneously to overpasses. To validate remotely sensed estimations, a preliminary prox…

Batch Methods for Resolution Enhancement of TIR Image Sequences

Thermal infrared (TIR) time series are exploited by many methods based on Earth observation (EO), for such applications as agriculture, forest management, and meteorology. However, due to physical limitations, data acquired by a single sensor are often unsatisfactory in terms of spatial or temporal resolution. This issue can be tackled by using remotely sensed data acquired by multiple sensors with complementary features. When nonreal-time functioning or at least near real-time functioning is admitted, the measurements can be profitably fed to a sequential Bayesian algorithm, which allows to account for the correlation embedded in the successive acquisitions. In this work, we focus on appli…

Dinamica costiera: individuazione della linea di riva e stima della sue incertezze

La linea di riva, ha natura dinamica, ovvero è sottoposta a continui cambiamenti, a breve e lungo termine, causati da processi geomorfologici, idrodinamici e da fattori improvvisi e rapidi. La ricerca esamina le problematiche legate all’incertezza nell’individuazione della posizione della linea di riva, al variare del tempo, considerando sia aspetti geologico - geomorfologici che aspetti idraulico marittimi. Il caso studio è un tratto di costa marsalese (Trapani). Tale settore è caratterizzato da una costa bassa con sedimenti sabbiosi d'età olocenica. L’analisi diacronica è stata basata su ortofoto e cartografie per il periodo di tempo compreso tra il 1994 e il 2006. È da precisare che la m…

Stima da remoto delle caratteristiche evapotraspirative e di umidità del sistema suolo-vegetazione di un impianto viticolo su morfologia complessa

Obiettivo della ricerca è la messa a punto di tecniche di elaborazione d’immagini telerilevate al fine di analizzare le caratteristiche evapotraspirative e di umidità del sistema suolo-vegetazione. La valutazione di tali grandezze è, infatti, di notevole interesse poiché consente alle aziende viticole di ottimizzare i processi di produzione nonché la qualità del prodotto. L’evapotraspirazione effettiva del sistema suolo-vegetazione (ETa) è stata stimata mediante l’applicazione del SEBAL (Surface Energy Balance Algorithm for Land), un modello di bilancio energetico facente uso d’immagini telerilevate nel campo riflessivo ed emissivo dello spettro. Il modello, implementato nella versione Moun…

Monitoring Mediterranean marine pollution using remote sensing and hydrodynamic modelling

Human activities contaminate both coastal areas and open seas, even though impacts are different in terms of pollutants, ecosystems and recovery time. In particular, Mediterranean offshore pollution is mainly related to maritime transport of oil, accounting for 25% of the global maritime traffic and, during the last 25 years, for nearly 7% of the world oil accidents, thus causing serious biological impacts on both open sea and coastal zone habitats. This paper provides a general review of maritime pollution monitoring using integrated approaches of remote sensing and hydrodynamic modeling; focusing on the main results of the MAPRES (Marine pollution monitoring and detection by aerial survei…

Surface soil water content estimation based on thermal inertia and Bayesian smoothing

Soil water content plays a critical role in agro-hydrology since it regulates the rainfall partition between surface runoff and infiltration and, the energy partition between sensible and latent heat fluxes. Current thermal inertia models characterize the spatial and temporal variability of water content by assuming a sinusoidal behavior of the land surface temperature between subsequent acquisitions. Such behavior implicitly supposes clear sky during the whole interval between the thermal acquisitions; but, since this assumption is not necessarily verified even if sky is clear at the exact epoch of acquisition, , the accuracy of the model may be questioned due to spatial and temporal varia…

Analisi multispettrale finalizzata al monitoraggio degli invasi in Sicilia: limiti e potenzialità

La diffusione crescente di laghetti collinari sul nostro territorio ha suggerito la possibilità di avviare un’attività di ricerca volta ad identificare la portata del fenomeno, la sua evoluzione nel tempo e l’incidenza che esso può avere sul bilancio idrologico e sulla stima della risorsa idrica disponibile. Con questo primo lavoro si è iniziato ad indagare i limiti e le potenzialità delle tecniche di elaborazione di dati remoti nell’identificazione degli invasi, di vario tipo, e nella stima della risorsa idrica da essi intercettata. La metodologia, basata sulla classificazione d’immagini multispettrali, è stata esaminata per diverse risoluzioni spaziali ed ha permesso di conseguire una sti…

Utilizzo di immagini in multispettrale da satellite per lo studio della variabilità di alcuni parametri vegetativi e produttivi del vigneto

Soil moisture retrieval using crop water stress indicators

Effetti della cultivar e del regime colturale sulla risposta spettrale della chioma di Vitis vinifera L.

Caratterizzazione della rugosità e dell’umidità del suolo tramite dati radar multifrequenza e multipolarizzazione

Mapping phycocyanin cells density of Planktothrix rubescens in freshwater reservoirs

On the relationship between some production parameters and a vegetation index in viticulture

The use and timing of many agronomical practices such as the scheduling of irrigation and harvesting are dependent on accurate vineyard sampling of qualitative and productive parameters. Crop forecasting also depends on the representativeness of vineyard samples during the whole phenological period. This manuscript summarizes the last two years of precision viticulture in Sicily (Italy); agronomic campaigns were carried out in 2012 and 2013 within the "Tenute Rapitalà" and "Donnafugata" farms. Normalized Difference Vegetation Index derived from satellite images (RapidEye) acquired at berry set, pre-veraison and ripening phenological stages (occurred at June, July and August respectively) ha…

Estimation of the time lag occurring between vegetation indices and aridity indices in a Sicilian semi-arid catchment

The evolution of drought phenomena in a Sicilian semi-arid catchment has been analyzed processing both remote sensing images and climatic data for the period 1985-2000. The remote sensing dataset includes Landsat TM and ETM+ multispectral images, while the climatic dataset includes monthly rainfall and air temperature. The results have been specifically discussed for areas where it is possible to neglect agricultural activities and vegetation growth is only influenced by natural forcing. The main outcome of this study is the quantification of the time lag between the remote sensing retrieved vegetation indices and the aridity indices (AIs) calculated from climatic data. Moreover the obtaine…

Approccio GIS (Geografical Information System) per la stima dei parametri produttivi del vigneto

On the Influence of Spatial Resolution on Submerged Vegetation Mapping Using Satellite Images

Monitoring marine water quality of Sicily by means of remotely sensed imagery

Within the framework of the GEOGRID research project, a semi-automatic computational chain has been implemented in order to map the time evolution of marine water quality, around Sicily island, by means of satellite images. To this aim a set of MODIS (TERRA and AQUA) multispectral images has been acquired. An automatic system to georeference and calibrate the images has been implemented. All the procedures to map clorophill-a, total suspended solids and turbidity come from the literature, whereas models parameters have been calibrated by means of in situ measurements.

Flow and turbulence characteristics in the presence of a discontinuous ligulate seagrass prairie

Mapping soil water content under sparse vegetation and changeable sky conditions: comparison of two thermal inertia approaches

A critical analysis of a thermal inertia approach to map surface soil water content on bare and sparsely vegetated soils by means of remotely sensed data is reported. The study area is an experimental field located in Barrax, Spain. In situ data were acquired within the Barrax 2011 research project. An advanced hyperspectral scanner airborne imager provides images in the visible/near-infrared and thermal infrared bands. Images were acquired both in day and night times by the Instituto Nacional de Técnica Aeroespacial between 12th and 13th of June 2011. The scene covers a corn irrigation pivot surrounded by bare soil, where a set of in situ data have been collected both previously and simult…

Monitoring Water Surface and Level of a Reservoir Using Different Remote Sensing Approaches and Comparison with Dam Displacements Evaluated via GNSS

Remote sensing allowed monitoring the reservoir water level by estimating its surface extension. Surface extension has been estimated using different approaches, employing both optical (Landsat 5 TM, Landsat 7 ETM+ SLC-Off, Landsat 8 OLI-TIRS and ASTER images) and Synthetic Aperture Radar (SAR) images (Cosmo SkyMed and TerraSAR-X). Images were characterized by different acquisition modes, geometric and spectral resolutions, allowing the evaluation of alternative and/or complementary techniques. For each kind of image, two techniques have been tested: The first based on an unsupervised classification and suitable to automate the process, the second based on visual matching with contour lines…

Indoor spectroradiometric characterization of plastic litters commonly polluting the Mediterranean Sea: toward the application of multispectral imagery

AbstractAround 350 million tonnes of plastics are annually produced worldwide. A remarkable percentage of these products is dispersed in the environment, finally reaching and dispersed in the marine environment. Recent field surveys detected microplastics’ concentrations in the Mediterranean Sea. The most commonly polymers found were polyethylene, polypropylene and viscose, ethylene vinyl acetate and polystyrene. In general, the in-situ monitoring of microplastic pollution is difficult and time consuming. The main goals of this work were to spectrally characterize the most commonly polymers and to quantify their spectral separability that may allow to determine optimal band combinations for…

On the use of unmanned aerial systems for environmental monitoring

[EN] Environmental monitoring plays a central role in diagnosing climate and management impacts on natural and agricultural systems; enhancing the understanding of hydrological processes; optimizing the allocation and distribution of water resources; and assessing, forecasting, and even preventing natural disasters. Nowadays, most monitoring and data collection systems are based upon a combination of ground-based measurements, manned airborne sensors, and satellite observations. These data are utilized in describing both small-and large-scale processes, but have spatiotemporal constraints inherent to each respective collection system. Bridging the unique spatial and temporal divides that li…

Critical Analysis Of Remote Sensing Techniques To Monitor Coastal Water Quality-Related Parameters

An automatic system for water quality assessment through MODIS L1B images

DETERMINAZIONE DELLE CARATTERISTICHE OTTICHE DI VEGETAZIONE SOMMERSA TRAMITE METODO MONTE CARLO

Si presentano i risultati di una ricerca volta alla determinazione della risposta spettrale della vegeta-zione sommersa mediante simulazioni stocastiche, con l’obiettivo di porre in risalto il range d’applicabilità (in termini di profondità e di lunghezza d’onda) delle tecniche di monitoraggio della vegetazione sommersa a partire da dati telerilevati. Per fare ciò è stato sviluppato e implementato un codice di calcolo che permette di ricostruire, mediante simulazioni stocastiche, la firma spettrale di oggetti posti sul fondale, una volta note le caratteristiche ottiche degli oggetti stessi e della colonna d’acqua. La flessibilità del modello di calcolo implementato ha inoltre permesso di es…

Use of differential SAR interferometry for detecting and measuring ground displacement due to a extensive landslide near Niscemi (Sicily, Italy)

Assessing the performance of a large-scale irrigation system by estimations of actual evapotranspiration obtained by Landsat satellite images resampled with cubic convolution

Abstract Remote sensing techniques allow monitoring the Earth surface and acquiring worthwhile information that can be used efficiently in agro-hydrological systems. Satellite images associated to computational models represent reliable resources to estimate actual evapotranspiration fluxes, ETa, based on surface energy balance. The knowledge of ETa and its spatial distribution is crucial for a broad range of applications at different scales, from fields to large irrigation districts. In single plots and/or in irrigation districts, linking water volumes delivered to the plots with the estimations of remote sensed ETa can have a great potential to develop new cost-effective indicators of irr…

Mapping evapotranspiration on vineyards: A comparison between Penman-Monteith and energy balance approaches for operational purposes

Estimation of evapotranspiration (ET) in Sicilian vineyard is an emerging issue since these agricultural systems are more and more converted from rainfed to irrigated conditions, with significant impacts on the management of the scarce water resources of the region. The choice of the most appropriate methodology for assessing water use in these systems is still an issue of debating, due to the complexity of canopy and root systems and for their high spatial fragmentation. In vineyards, quality and quantity of the final product are dependent on the controlled stress conditions to be set trough irrigation. This paper reports an application of the well-known Penman-Monteith approach, applied i…

Comparing actual evapotranspiration and plant water potential on a vineyard

Agricultural water requirement in arid and semi-arid environments represents an important fraction of the total water consumption, suggesting the need of appropriate water management practices to sparingly use the resource. Furthermore the quality and quantity of some crops products, such as grape, is improved under a controlled amount of water stress. The latter is related, on a side to actual evapotranspiration (ET) through water demand, on the other side to plant water content through leaf water potential. Residual energy balance approaches based on remote sensing allow to estimate the spatial distribution of daily actual ET at plant scale, representing an useful tool to detect its spati…

Using very high resolution (VHR) imagery within a GEOBIA framework for gully mapping: an application to the Calhoun Critical Zone Observatory

AbstractGully erosion is a form of accelerated erosion that may affect soil productivity, restrict land use, and lead to an increase of risk to infrastructure. An accurate mapping of these landforms can be difficult because of the presence of dense canopy and/or the wide spatial extent of some gullies. Even where possible, mapping of gullies through conventional field surveying can be an intensive and expensive activity. The recent widespread availability of very high resolution (VHR) imagery has led to a remarkable growth in the availability of terrain information, thus providing a basis for the development of new methodologies for analyzing Earth's surfaces. This work aims to develop a ge…

Confronto tra evapotraspirazione effettiva e potenziale idrico fogliare da dati telerilevati e micrometeorologici

The synergy of water quality and sea surface currents data in determining the spatio-temporal evolution of large-scale circulation features

Chlorophyll-a (CHL-a) and Sea Surface Temperature (SST), amongst others, are proxies or indicators for water quality and can be easily retrieved synoptically and almost in near-real time through satellite remote-sensing. However, as they evolve in space and time in response to winds and currents, a full resolution of the temporal and spatial scales of these latters is required and their influence in shaping the distribution of water quality parameters needs to be assessed. While providing synoptic views and revealing mesoscale features, satellites suffer, indeed, from inadequate representation of sub-grid physical processes and lack of temporal resolution. Conventional point-wise measuremen…

Comparison of potential vs. actual vegetation status by means of distributed hydrological bilance model and remore sensing data

A geostatistical approach to map near-surface soil moisture through hyperspatial resolution thermal inertia.

Thermal inertia has been applied to map soil water content exploiting remote sensing data in the short and long wave regions of the electromagnetic spectrum. Over the last years, optical and thermal cameras were sufficiently miniaturized to be loaded onboard of unmanned aerial systems (UASs), which provide unprecedented potentials to derive hyperspatial resolution thermal inertia for soil water content mapping. In this study, we apply a simplification of thermal inertia, the apparent thermal inertia (ATI), over pixels where underlying thermal inertia hypotheses are fulfilled (unshaded bare soil). Then, a kriging algorithm is used to spatialize the ATI to get a soil water content map. The pr…

Exploring the use of Unmanned Aerial Vehicles (UAVs) with the simplified ‘triangle’ technique for soil water content and evaporative fraction retrievals in a Mediterranean setting

Participation of Dr. Petropoulos has been funded by the ENViSIoN-EO Marie Skłodowska-Curie grant (grant No 752094), part of the European Union’s Horizon 2020 research and innovation programme. Part of the present collaborative work was also materialised in the framework of a short Term Scientific Mission (STSM) of the HARMONIOUS Cost Action which financially supported Dr Petropoulos’ visit between 4 to 15 February 2020 to the Department of Engineering of the University of Palermo, Italy. Η συμμετοχή του Δρ. Πετρόπουλου χρηματοδοτήθηκε από το πρόγραμμα της Ευρωπαϊκής Ένωσης για Έρευνα και Καινοτομία «Oρίζοντας 2020», δράση Marie Sklodowska - Curie , έργο ENViSIoN-EO (αριθ. 752094). Επίσης μέ…

E.O.-based estimation of transpiration and crop water requirements for vineyards: a case study in southern Italy

An efficient use of water for irrigation is a challenging task. From an agronomical point of view, it requires establishing the optimal amount of water to be supplied, at the correct time, based on phenological phase and water stress spatial distribution. Indeed, the knowledge of the actual water stress is essential for agronomic decisions, vineyards need to be managed to maintain a moderate water stress, thus allowing to optimize berries quality and quantity. Methods for quickly quantifying where, when and in what extent, vines begin to experience water stress are beneficial. Traditional point based methodologies, such those based on Scholander pressure chamber, even if well established ar…

Utilizzo della termografia per l’individuazione dell’infestazione da punteruolo rosso, la ricerca scientifica sul punteruolo rosso e gli altri fitofagi delle palme in Sicilia

Optical properties of Sicilian lakes during a Cyanophycea Planktothrix rubescens algal bloom

In December 2006 blooms of Planktothrix rubescens were found in the reservoir Prizzi in Sicily. Planktothrix is a genus of filamentous alga comprising approximately 6 species, between these the P. rubescens is sadly famous since this organism produces microcystins which are powerful hepatotoxins. Firstly found in Europe in 1825 on Geneva lake, recently (2006) those algae has been find out in Pozzillo, Nicoletti e Ancipa reservoirs (Enna Province), as well as in Prizzi (Palermo Province) and Garcia reservoirs (Trapani Province). Toxins produced by those bacteria (usually called microcystine LR-1 and LR-2) are highly toxic since they can activate oncogenes cells causing cancer pathologies on …

Coupling SAR X-band and optical data for NDVI retrieval: model calibration and validation on two test areas

Sustainability of modern agro-hydrology requires the knowledge of spatial and temporal variability of vegetation biomass to optimize management of land and water resources. Diversely from optical imaging, temporal resolution of active sensors, such as SAR, is not limited by sky cloudiness; thus, they may be combined with optical imageries to provide a more continuous monitoring of land surfaces. Several new SAR missions (e.g., ALOS-PALSAR, COSMO-SkyMed 1 and 2, TerraSAR-X, TerraSAR-X2, Sentinel 1) acquiring at X-, C- and L-bands and dual polarization capability, are characterized by a short revisit time (from 12 h to ~10 days) and high spatial resolution (<20 m). These satellites could prov…

Mapping evapotranspiration on vineyards: The Sentinel-2 potentiality

stimation of actual evapotranspiration in Sicilian vineyards, is an emerging issue since these agricultural systems. Indeed unlike other agricultural species (Vitis vinifera L. ) are generally cultivated under mild water stress, in order to enhance quality (Guadillère et al. , 2002. This has significant impacts on the management of the scarce water resources of the region. The choice of the most appropriate methodology for assessing water use in these systems is still an issue of debating, due to the complexity of canopy and root systems and for their high spatial fragmentation. In vineyards, quality and quantity of the final product are dependent on the controlled stress conditions to be s…

Sensitivity analysis on the relationship between vegetation growth and multi-polarized radar data

Spatially distributed soil moisture is required for watershed applications such as drought and flood prediction, crop irrigation scheduling, etc. In particular, an accurate assessment of the spatial and temporal variation of soil moisture is necessary to improve the predictive capability of runoff models, and for improving and validating hydrological processes forecasting. In recent years, several models have been developed in order to retrieve soil moisture using RADAR data. However, these models need precise prior knowledge about surface roughness. Within this framework, the present research aims to investigate the capabilities of multi polarimetric RADAR images to overcome the use of in …

Coherent flow and turbulence structures in fragmented meadows of the mediterranean seagrass posidonia oceanica

Power sensitivity analysis of multi-frequency, multi-polarized, multi-temporal SAR data for soil-vegetation system variables characterization

Abstract: The knowledge of spatial and temporal variability of soil water content and others soil-vegetation variables (leaf area index, fractional cover) assumes high importance in crop management. Where and when the cloudiness limits the use of optical and thermal remote sensing techniques, synthetic aperture radar (SAR) imagery has proven to have several advantages (cloud penetration, day/night acquisitions and high spatial resolution). However, measured backscattering is controlled by several factors including SAR configuration (acquisition geometry, frequency and polarization), and target dielectric and geometric properties. Thus, uncertainties arise about the more suitable configurati…

Modelling soil carbon fate under erosion process in vineyard

Soil erosion processes in vineyards beyond water runoff and sediment transport have a strong effect on soil organic carbon loss (SOC) and redistribution along the slope. The variation of SOC across the landscape determines a difference in soil fertility and vine productivity. The aim of this research was to study erosion of a Mediterranean vineyard, develop an approach to estimate the SOC loss, correlate the vines vigor with sediment and carbon erosion. The study was carried out in a Sicilian (Italy) vineyard, planted in 2011. Along the slope, six pedons were studied by digging 6 pits up to 60cm depth. Soil was sampled in each pedon every 10cm and SOC was analyzed. Soil erosion, detachment …

Effects of rainfall events on the evapotranspiration retrieved by an energy balance model

An alternative way to map the actual evapotranspiration (ET) spatial distribution at daily scale is the application of residual surface energy balance models to satellite images that are characterised by high temporal frequency and moderate spatial resolution, like those acquired by the MODIS sensors on board of TERRA and AQUA platforms. Within this research the well-known SEBAL model has been applied on an area located in the southern part of Sicily (Imera Meridionale catchment) using four images acquired between the 27th of March and the 11th of April 2007. The catchment extends for about 2000 km2 and includes both mountains and hill areas: the first are located in the northern part (the …

On the Accuracy of Cadastral Marks: Statistical Analyses to Assess the Congruence among GNSS-Based Positioning and Official Maps

Cadastral marks constitute a dense source of information for topographical surveys required to update cadastral maps. Historically, in Italy, cadastral marks have been the cartographic network for the implementation of mapping updates. Different sources of cadastral marks can be used by cadastral surveyors. In recent years, the cadastre is moving toward a digital world, and with the advancement of surveying technology, GNSS CORS technology has emerged in the positioning of cadastral marks. An analysis of congruence among cadastral marks using GNSS CORS and official maps is missing. Thus, this work aims to analyze the positional accuracy of some cadastral marks, located in Palermo, Italy, wi…

Processing hyperspectral mivis data in order to monitor submerged vegetation in shallow water

Proximal-sensing-powered modelling of energy-water fluxes in a vineyard: A spatial resolution analysis

Spatial resolution is a key parameter in energy–water surface flux modelling. In this research, scale effects are analyzed on fluxes modelled with the FEST-EWB model, by upscaling both its inputs and outputs separately. The main questions are: (a) if high-resolution remote sensing images are necessary to accurately model a heterogeneous area; and (b) whether and to what extent low-resolution modelling provides worse/better results than the upscaled results of high-resolution modelling. The study area is an experimental vineyard field where proximal sensing images were obtained by an airborne platform and verification fluxes were measured via a flux tower. Modelled fluxes are in line with th…

Assessing the performance of thermal inertia and Hydrus models to estimate surface soil water content

The knowledge of soil water content (SWC) dynamics in the upper soil layer is important for several hydrological processes. Due to the difficulty of assessing the spatial and temporal SWC dynamics in the field, some model-based approaches have been proposed during the last decade. The main objective of this work was to assess the performance of two approaches to estimate SWC in the upper soil layer under field conditions: the physically-based thermal inertia and the Hydrus model. Their validity was firstly assessed under controlled laboratory conditions. Thermal inertia was firstly validated in laboratory conditions using the transient line heat source (TLHS) method. Then, it was applied in…

Assessing daily actual evapotranspiration through energy balance: an experiment to evaluate the selfpreservation hypothesis with acquisition time

An operational use of the actual evapotranspiration estimates requires the integration from instantaneous to daily values. This can commonly be achieved under the hypothesis of daytime self-preservation of the evaporative fraction. In this study, it has been evaluated the effect of this assumption on the assessment of daily evapotranspiration from proximity sensing images acquired at hourly intervals over a homogeneous olive groove. Results have been validated by comparison with observations made by a micrometeorological (EC-flux tower) and an eco-physiological (sap flux) sensor. SEBAL model has been applied to thermal and multispectral images acquired during a clear day on August 2009 trou…

Analisi evolutiva della distribuzione della vegetazione sommersa in una laguna per mezzo di dati iperspettrali MIVIS

Front Matter: 7472

Critical analysis of empirical ground heat flux equations on a cereal field using micrometeorological data

The rate at which the net radiation is transferred to the soil as ground heat flux varies with surface characteristics. Surface energy balance algorithms use empirical relationships taking into account the effects of the canopy cover to insulate the soil through vegetation indexes, the soil capacity to absorb incoming net radiation via the albedo, and the surface temperature promoting the energy transfer. However empirical relationships are often dependent on local conditions, such as the soil humidity and vegetation type. Ground heat flux assumes a minimum value in case of full canopy cover and a maximum value for dry bare soil. Aim of the present research is the critical analysis of some …

Coupling two radar backscattering models to assess soil roughness and surface water content at farm scale

Remote sensing techniques are useful for agro-hydrological monitoring at the farm scale because the availability of spatially and temporally distributed data improves agricultural models for irrigation and crop yield optimization under water scarcity conditions. This research focuses on the surface water content retrieval using active microwave data. Two semi-empirical models were chosen as these showed the best performances in simulating cross and co-polarized backscatter. Thus, these models were coupled to obtain reliable assessments of both soil water content and soil roughness. The use of the coupled model enables one to avoid using roughness measured in situ. Remote sensing images and …

Mediterranean Maritime Pollution: The Role Of Remote Sensing To Monitor And Mitigate

Particle tracking in a gap of aquatic vegetation meadow

Aquatic vegetation considerably affects the flow field in water bodies, with influence increasing as the depth decreases. As a consequence, vegetation also affects suspended particle transport. In inshore sandy beds less than 40 m deep of the Mediterranean Sea, meadows of Posidonia oceanica are widespread. This plant is constituted by a tuft of very thin and flexible ribbon-like leaves about 1 cm wide and up to 1.5 m long; the meadow areal density can reach 1000-1200 plant/m2. Frequently, such meadows are not continuous but vegetated areas alternate with sand strips (“gaps”). The presence of such discontinuities noticeably affects the flow field and gaps can actually act as particle traps. …

Soil Water Content Assessment: Critical Issues Concerning the Operational Application of the Triangle Method

Knowledge of soil water content plays a key role in water management efforts to improve irrigation efficiency. Among the indirect estimation methods of soil water content via Earth Observation data is the triangle method, used to analyze optical and thermal features because these are primarily controlled by water content within the near-surface evaporation layer and root zone in bare and vegetated soils. Although the soil-vegetation-atmosphere transfer theory describes the ongoing processes, theoretical models reveal limits for operational use. When applying simplified empirical formulations, meteorological forcing could be replaced with alternative variables when the above-canopy temperatu…

Surface soil humidity retrieval by means of a semi-empirical coupled SAR model

In the last years, the availability of new technologies of Earth Observation encouraged researches to use integrated approaches for environmental monitoring. Even for agro-hydrological applications, remotely sensed data are available on wide areas allowing the retrieval of cost-effective and representative estimation of high spatial and temporal variability of the soil-vegetation system variables. In particular, soil water content plays an important role determining the partition of precipitation between surface runoff and infiltration and, moreover, influences the distribution of the incoming radiation between latent and sensible heat flux. As a consequence, distributed soil water content …

Trasporto di particelle sospese in una discontinuità di un prato di vegetazione acquatica

La vegetazione acquatica influenza sensibilmente il campo di moto e il trasporto solido nei corpi idrici. Nelle aree sottocosta del Mar Mediterraneo sono molto diffusi i prati di Posidonia oceanica, una pianta costituita da un ciuffo di foglie nastriformi molto lunghe e flessibili. Spesso i prati sono interrotti da frequenti strisce di sabbia, e tali discontinuità, modificando sensibilmente il campo di moto, possono agire come “trappole” per i sedimenti. Nella presente memoria, sulla base di un campo di moto sperimentale, si simula numericamente il trasporto di particelle sospese in una tale discontinuità. A tal fine si adotta un semplice modello lagrangiano che assume assenza di velocità r…

Influenza del clima ondoso e delle mareee sulla posizione della linea di riva: Lido Signorino (Marsala)

La conoscenza della posizione della linea di riva nel tempo è indispensabile per verificare la necessità di opere di difesa e per lo sviluppo di piani di gestione costiera. Essa rappresenta l’intersezione tra la superficie marina e quella terrestre, non è un’entità geometrica fissa, ma varia continuamente a causa del moto ondoso e delle fluttuazioni del livello marino ed è in continuo movimento a causa dei fenomeni di trasporto solido. La maggior difficoltà riscontrata nelle operazioni di rilievo è la determinazione esatta della sua posizione. Risulta pertanto necessaria la comprensione delle caratteristiche del moto ondoso (conoscenza delle mareggiate), dei livelli marini e del profilo tra…

Indagine sulla vulnerabilità alla desertificazione mediante l’utilizzo di dati termopluviometrici e telerilevati

NRTK, PPP or Static, That Is the Question. Testing Different Positioning Solutions for GNSS Survey

Worldwide, the determination of the coordinates from a Global Navigation Satellite System (GNSS) survey (in Network Real Time Kinematic, Precise Point Positioning, or static mode) has been analysed in several scientific and technical applications. Many of those have been carried out to compare Precise Point Positioning (PPP), Network Real Time Kinematic (NRTK), and static modes’ solutions, usually, using the latter as the true or the most plausible solution. This approach is not always possible as the static mode solution depends on several parameters (baseline length, acquisition time, ionospheric, and tropospheric models, etc.) that must be considered to evaluate the accuracy of the metho…

Sprectroradiometric characteristics of inland water bodies infestated by Oscillatoria rubescens algae

In December 2006 blooms of Oscillatoria rubescens were found in the reservoir Prizzi in Sicily. Oscillatoria is a genus of filamentous alga comprising approximately 6 species, between these the O. rubescens is sadly famous since this organism produces microcystins which are powerful hepatotoxins. Firstly found in Europe in 1825 on Geneva lake, recently (2006) those algae has been find out in Pozzillo, Nicoletti e Ancipa reservoirs (Enna Province), as well as in Prizzi (Palermo Province) and Garcia reservoirs (Trapani Province). Toxins produced by those bacteria (usually called microcystine LR-1 and LR-2) are highly toxic since they can activate oncogenes cells causing cancer pathologies on …

Caratterizzazione della vegetazione mediante immagini NOAA-AVHRR e modellistica idrologica

Comparison of methods to estimate LAI from remote sensing in maize canopies by inversion of 1-D and 3-D models

The inversion of canopy reflectance models is a procedure widely employed for the retrieval of LAI from remote sensing. However the accuracy of the estimates depends on a range of factors, most notably the realism of the canopy representation of the models employed and the a priori knowledge of some vegetation characteristics. The objective of the present work was to compare the performances and the operational limitations of the use of two contrasting type of radiative transfer models: a classical one-dimensional canopy reflectance model, PROSPECT+SAIL (PROSAIL) and a three-dimensional dynamic maize model (Lopez-Lozano et al., 2007) having greater realism in the description of the canopy s…

Latent heat flux variability and response to drought stress of black poplar: A multi-platform multi-sensor remote and proximal sensing approach to relieve the data scarcity bottleneck

Abstract High-throughput mapping of latent heat flux (λET) is critical to efforts to optimize water resources management and to accelerate forest tree breeding for improved drought tolerance. Ideally, investigation of the energy response at the tree level may promote tailored irrigation strategies and, thus, maximize crop biomass productivity. However, data availability is limited and planning experimental campaigns in the field can be highly operationally complex. To this end, a multi-platform multi-sensor observational approach is herein developed to dissect the λET signature of a black poplar (Populus nigra) breeding population (“POP6”) at the canopy level. POP6 comprised more than 4600 …

On the Use of the Eddy Covariance Latent Heat Flux and Sap Flow Transpiration for the Validation of a Surface Energy Balance Model

Actual evapotranspiration is assessed via surface energy balance at an hourly rate. However, a robust estimation of daily evapotranspiration from hourly values is required. Outcomes of surface energy balance are frequently determined via measures of eddy covariance latent heat flux. Surface energy balance can be applied on images acquired at different times and spatial resolutions. In addition, hourly actual evapotranspiration needs to be integrated at a daily rate for operational uses. Questions arise whether the validation of surface energy balance models can benefit from complementary in situ measures of latent heat flux and sap flow transpiration. Here, validation was driven by image ac…

On the processing of field spectroradiometric data for remote sensing mapping of submerged vegetation in coastal zones and lagoon environments

Surface soil humidity retrieval using remote sensing techniques: a triangle method validation

Soil humidity plays a key-role in hydrological and agricultural processes. In the rainfall-runoff processes the knowledge of its spatial distribution is fundamental to accurately model these phenomena. Furthermore in agronomy and agricultural sciences, assessing the water content of the root zone is required in order to optimize the plant productivity and to improve the irrigation systems management. Despite the importance of this variable the in situ measurements techniques based on Time Domain Reflectometry (TDR) or on the standard thermo-gravimetric methods, are neither cost-effective nor representative of its spatial and temporal variability. Indirect estimations via Earth Observation (…

Mappatura della vegetazione sommersa mediante immagini multispettrali telerilevate da satellite

Comparative Analysis Between Actual and Potential Evapotranspiration in a Sicilian Semi-Arid Catchment

Telerilevamento di aree archeologiche mediante dati iperspettrali MIVIS” (Remote sensing of archaelogical areas using hyperspectral MIVIS data)

The aim of this study is to examine the relationship between physical parameters and the spatial distribution of buried archaeological structures, using data acquired by the airborne hyperspectral sensor mivis in the visible, near infrared and thermal infrared wavelengths. The study areas are the territories of Halaesa, an important city in the Hellenistic-Roman period, and the Punic city of Mozia in Sicily. The influence of buried structures on thermal-radiative behaviour has been investigated using three parameters: Normalized Difference Vegetation Index (ndvi), thermal inertia, and Thermal Balanced Gradient. These techniques are shown to be particularly effective in identifying surface p…

Integration of terrestrial laser scanning and UAV-SFM technique to generate a detailed 3D textured model of a heritage building

The digital twin is among the Top 10 of the strategic technological trends for the period 2007-2019, and it represents a powerful tool for the conservation and enhancement of cultural heritage. It reproduces with "precision" a physical asset, thus allowing to investigate its structure and to analyze the deformations that occur over the years. Various techniques have been introduced to obtain high-resolution 3D models. Among these, the Terrestrial Laser Scanner (TLS) is widely recognized as the gold standard to generate accurate 3D metric reconstructions. TLS allows acquiring a lot of data (point cloud) in a fast way, being not in physical contact with the objects of investigation. By integr…

Comparison of Potential VS actual vegetation status by means of distributed hydrologic balance model and remote sensing data

Determinazione dell’umidità del sistema suolo-vegetazione mediante tecniche di remote sensing: una verifica del metodo triangolare

Enhancing TIR Image Resolution via Bayesian Smoothing for IRRISAT Irrigation Management Project

Accurate estimation of physical quantities depends on the availability of High Resolution (HR) observations of the Earth surface. However, due to the unavoidable tradeoff between spatial and time resolution, the acquisition instants of HR data hardly coincides with those required by the estimation algorithms. A possible solution consists in constructing a synthetic HR observation at a given time k by exploiting Low Resolution (LR) and HR data acquired at different instants. In this work we recast this issue as a smoothing problem, thus focusing on cases in which observations acquired both before and after time k are available. The proposed approach is validated on a region of interest for t…

Effetto della cultivar e del regime colturale sulla risposta spettrale della chioma in Vitis vinifera L.

Lo studio consente di caratterizzare le risposte spettrali all’invaiatura di chioma ed acino di alcune cultivar a bacca nera della piattaforma ampelografica siciliana. La variabilità tra le risposte spettrali delle foglie all’interno della stessa chioma, nonché le variazioni spettrali anche al variare del regime irriguo consentono di effettuare un’analisi comparativa delle cultivar. In questo quadro, le firme spettrali integrano la descrizione ampelografica di chioma e bacche che caratterizza la Vitis Vinifera L.. Infine l’applicazione su un’area pilota di tecniche di classificazione di immagini remote basate sulle caratteristiche spettrali delle cultivar, consente di valutarne le performan…

Regional Soil Moisture Retrieval Using Remotely Sensed Crop Water Stress Indicators

The classification of submerged vegetation using hyperspectral MIVIS data

The aim of this research is to use hyperspectral MIVIS data to map the Posidonia oceanica prairies in a coastal lagoon (Stagnone di Marsala). It is approximately 12 km long and 2 km wide and is linked to the open sea by two shallow openings. This environment is characterised by prairies of phanerogams, the most common of which is Posidonia oceanica, an ideal habitat for numerous species of fish, molluscs and crustaceans. A knowledge of the distribution of submerged vegetation is useful to monitor the health of the lagoon. In order to classify the MIVIS imagery, the attenuation effects of the water column have been removed from the signal using Lyzenga’s technique. A comparison between class…

Detection of a reservoir water level using shape similarity metrics

The matching between reservoirs’ water edge and digital elevation model’s (DEM) contour lines allowed determining the water level at the acquisition date of satellite images. A preliminary study was conducted on the Castello dam (Magazzolo Lake), between Alessandria della Rocca and Bivona (Agrigento, south-Italy). The accuracy assessment of the technique was than evaluated from the comparison between classified and reference objects using similarity metrics about the shape, theme, edge and position, through the plugin STEP of open source software GIS. Moreover, an independent GIS technique was implemented to evaluate the water level, based on a distances’ array between existing contour line…

Coastal zone water quality: Calibration of a water-turbidity equation for MODIS data

AbstractA nephelometric turbidity algorithm has been specifically calibrated for coastal waters in Sicily. To this purpose, intensive field campaigns were performed in July, August and September 2008. Measurements were collected in situ in three different gulfs. Statistical analysis suggests that field data should be spatially grouped but temporally separated; hence, new calibration parameters have been proposed.Turbidity retrieved by applying the algorithm using literature coefficients and the ones calibrated in situ are shown and compared. The comparison demonstrated that a specific calibration was necessary for quantitatively monitoring turbidity in Sicilian gulfs.

Effects of morphology on watershed actual evapotranspiration estimation by means of SEBAL model

Vegetation index retrieval by coupling optical and SAR images

Monitoring spatial and temporal variability of Vegetation Indices (VIs) is important to manage land and water resources, with significant impact on the sustainability of modern agriculture Although algorithms based on optical data give accurate products, cloud cover dramatically reduces the temporal resolution of these outputs. The launch of new Synthetic Aperture Radar (SAR) constellations such as COSMO-Skymed opened new opportunities to develop agro-hydrological applications. Indeed, these satellites may represent a suitable source of data for operational applications due to their high spatial and temporal resolutions (10 m in StripMap PingPong acquisition mode, best revisit time with 4 s…

Misure termografiche da pallone aerostatico per la diagnosi precoce di attacchi da punteruolo rosso delle palme

Planktothrix rubescens in freshwater reservoirs: The Sentinel-2 potentiality for mapping phycocyanin concentration

In December 2006 blooms of Planktothrix rubescens were found in the Prizzi reservoir in Sicily. P. rubescens is sadly famous for producing microcystins (MC), which are harmful hepatotoxins. Recently (2006) P. rubescens has been found in the Pozzillo, Nicoletti, Ancipa, Prizzi and Garcia reservoirs. This paper compares the optical properties of the water of an infested reservoir and those of a clear water reservoir. Furthermore it evaluates an empirical method based on bands product to evaluate the phycocyanin cell density from MODIS, Landsat ETM+ and Sentinel-2 images. Spectroradiometric field campaigns were carried out in February/March 2008 to quantify the spectral transparencies of two w…

Daytime sensible heat flux estimation over heterogeneous surfaces using multitemporal land-surface temperature observations

Equations based on surface renewal (SR) analysis to estimate the sensible heat flux (H) require as input the mean ramp amplitude and period observed in the ramp-like pattern of the air temperature measured at high frequency. A SR-based method to estimate sensible heat flux (HSR-LST) requiring only low-frequency measurements of the air temperature, horizontal mean wind speed, and land-surface temperature as input was derived and tested under unstable conditions over a heterogeneous canopy (olive grove). HSR-LST assumes that the mean ramp amplitude can be inferred from the difference between land-surface temperature and mean air temperature through a linear relationship and that the ramp freq…

Coupling a hydro-maritime model and remotely sensed techniques to assess the shoreline positioning uncertainty: the Marsala coast study case

The severe erosion phenomena affecting the Mediterranean coasts are strictly related to geophysical characteristics and socio-economic pressures. This suggests the need of monitoring and modelling the phenomenon in order to quantify its strength. In fact, the shoreline position, as well as its temporal evolution, provides important information for designing defence structures and for the development of a coastal management plan. The shoreline has a dynamic nature as it changes both in the short and long period. Those changes are caused by geo-morphological (e.g. bars and barrier island development etc.) and hydrodynamic (wave motion, tides and flows) processes, as well as by sudden and fast…

Integrazione di dati telerilevati in modelli idrologici: pre-elaborazione di immagini riprese da sensori aviotrasportati CASI ed ATM

Daily evapotranspiration assessment by means of residual surface energy balance modeling: A critical analysis under a wide range of water availability

Summary An operational use of the actual evapotranspiration assessed by remote sensing approaches requires the integration of instantaneous fluxes to daily values. This is commonly achieved under the hypotheses of daytime self-preservation of evaporative fraction and negligible daily ground heat flux. The aim of this study is to evaluate the effect of these assumptions on estimate daily evapotranspiration over a full phenological cycle, including phases characterized by significant changes both in net radiation and vegetation cover. To assess the reliability of these hypotheses, the observations made by a flux tower, installed within a homogeneous field of cereal located in the valley part …

The use of the Specht distributed hydrologic balance model for an analysis of vegetation state

Post-processing of Pixel and Object-Based Land Cover Classifications of Very High Spatial Resolution Images

The state of the art is plenty of classification methods. Pixel-based methods include the most traditional ones. Although these achieved high accuracy when classifying remote sensing images, some limits emerged with the advent of very high-resolution images that enhanced the spectral heterogeneity within a class. Therefore, in the last decade, new classification methods capable of overcoming these limits have undergone considerable development. Within this research, we compared the performances of an Object-based and a Pixel-Based classification method, the Random Forests (RF) and the Object-Based Image Analysis (OBIA), respectively. Their ability to quantify the extension and the perimeter…

Using Optical and Thermal Data for Tracking Snowmelt Processes in Alpine Area

Alpine catchments represent a fundamental reservoir of fresh water at midlatitude. Remote sensing offers the opportunity to estimate snow properties in the optical, thermal and microwave domains. In particular, the possibility to estimate snow density from remote sensing is relevant and still represents a great challenge for the remote sensing scientific community. Since changes of snow density and liquid water content occur continuously in the snowpack, spatial and temporal patterns of optical and thermal data can give information about snowmelt processes. The main goal of this study is to evaluate if snow thermal inertia can be an indicator of snowmelt processes and to evaluate its relati…

On the influence of flexible vegetation on flow fields in shallow water: a flume experiment

Validation of HF radar sea surface currents in the Malta-Sicily Channel

Abstract A network of High-Frequency radar (HFR) stations runs operationally in the Malta-Sicily Channel (MSC), Central Mediterranean Sea, providing sea surface current maps with high temporal (1 h) and spatial (3 × 3 km) resolutions since August 2012. Comparisons with surface drifter data and near-surface Acoustic Doppler Current Profiler (ADCP) observations, as well as radar site-to-site baseline analyses, provide quantitative assessments of HFR velocities accuracy. Twenty-two drifters were deployed within the HFR domain of coverage between December 2012 and October 2013. Additionally, six ADCP vertical current profiles were collected at selected positions during a dedicated field survey.…

Analisi multitemporale delle relazioni tra parametri produttivi e indice di vegetazione in viticoltura

L’efficacia degli interventi agronomici dipendono dalla capacità di programmazione in termini di tempo e intensità di intervento. Questultimi aspetti possono essere calibrati tramite una corretta conoscenza delle caratteristiche produttive e qualitative dei parametric di campo e della loro variabilità nel tempo e nello spazio. La viticoltura di precisione fornisce un supporto valido alla definizione della variabilità di campo e temporale dei parametric vegetative e produttivi. Questo lavoro sintetizza due anni di viticoltura di precisione in Sicilia, nelle campagne agronomiche consotte nel 2012 e 2013 in due aziende vitivinicole “Tenute Rapitalà” e “Donnafugata”. L’indice di vegetazione nor…

The impact of soil erosion on soil fertility and vine vigor. A multidisciplinary approach based on field, laboratory and remote sensing approaches

Soil erosion processes in vineyards, beyond surface runoff and sediment transport, have a strong effect on soil organic carbon (SOC) loss and redistribution along the slope. Variation in SOC across the landscape can determine differences in soil fertility and vine vigor. The goal of this research was to analyze the interactions among vines vigor, sediment delivery and SOC in a sloping vineyard located in Sicily. Six pedons were studied along the slope by digging 6 pits up to 60 cm depth. Soil was sampled every 10 cm and SOC, water extractable organic carbon (WEOC) and specific ultraviolet absorbance (SUVA) were analyzed. Erosion rates, detachment and deposition areas were measured by the po…

On the influences of vegetation biomass on COSMO-Skymed X-band

The knowledge of spatial and temporal variability of land cover is important to manage water resources for yield forecasting, water stress prediction, irrigation water management and flood protection. Cloud cover dramatically reduces the temporal resolution of optical data thus limiting their operational use; in addition, the spatial resolution is often inadequate for applications in heterogeneous areas. On the other hand, algorithms based on Synthetic Aperture Radar (SAR) implemented to retrieve vegetation parameters are not yet fully validated. New SAR missions (COSMO-Skymed and Terrasar-X) may represent a suitable source of data for operational uses due to the high spatial and temporal r…

Critical analysis of thermal inertia approaches for surface soil water content retrieval

The “thermal inertia” method to retrieve surface soil water content maps on bare or sparsely-vegetated soils is analysed. The study area is a small experimental watershed, where optical and thermal images (in day and night time) and in situ data were simultaneously acquired. The sensitivity of thermal inertia to the phase difference between incoming radiation and soil temperature is demonstrated. Thus, to obtain an accurate value of the phase difference, the temporal distance between thermographs using a three-temperature approach is evaluated. We highlight when a cosine correction of the temperature needs to be applied, depending on whether the thermal inertia formulation includes two gene…

Tecnica Differenziale Interferometrica per l’individuazione di un dissesto: il caso della frana di Niscemi

Thermal inertia modeling for soil surface water content estimation: A laboratory experiment

We are proposing a new method for estimating soil surface water content from thermal inertia distributions retrieved from visible–near infrared (VISNIR)and thermal infrared (TIR) images. A drying experiment was conducted on three fi ne-textured soils while acquiring multispectral VIS-NIR and TIR images. Simultaneous measurements of soil water content and thermal inertia were conducted by the thermogravimetric method and the heat pulse technique, respectively. Direct measurements were used to test the thermal inertia approach proposed by Murray and Verhoef that requires only knowledge of soil porosity and can be easily inverted to derive soil water content from thermal inertia. For the three…

Introducing Thermal Inertia for Monitoring Snowmelt Processes With Remote Sensing

Thermal inertia has been successfully used in remote sensing applications that span from geology, geomorphology to hydrology. In this paper, we propose the use of thermal inertia for describing snow dynamics. Two different formulations of thermal inertia were tested using experimental and simulated data related to snowpack dynamics. Experimental data were acquired between 2012 and 2017 from an automatic weather station located in the western Italian Alps at 2,160 m. Simulations were obtained using the one‐dimensional multilayer Crocus model. Results provided evidences that snowmelt phases can be recognized, and average snowpack density can be estimated reasonably well from thermal inertia o…

Telerilevamento di aree archeologiche mediante dati iperspettrali MIVIS

The aim of this study is to examine the relationship between physical parameters and the spatial distribution of buried archaeological structures, using data acquired by the airborne hyperspectral sensor MIVIS in the visible, near infrared and thermal infrared wavelengths. The study areas are the territories of Halaesa, an important city in the Hellenistic-Roman period, and the Punic city of Mozia in Sicily. The influence of buried structures on thermal-radiative behaviour has been investigated using three parameters: Normalized Difference Vegetation Index (NDVI), thermal inertia, and Thermal Balanced Gradient. These techniques are shown to be particularly effective in identifying surface p…

Assessing the performance of different model-based techniques to estimate water content in the upper soil layer

he knowledge of soil water content (SWC) of the upper soil layer is important for most hydrological processes occurring over vegetated areas and under dry climate. Because direct field measurements of SWC are difficult, the use of different type of sensors and model-based approaches have been proposed and extensively used during the last decade. The main objective of this work is to assess the performance of two models estimating SWC of the upper soil layer: the transient line heat source method and the physically based Hydrus-1D model. The models' performance is assessed using field measurements acquired through a Time Domain Reflectometer (TDR). The experiment was carried out on an olive …

An interpolation-based data fusion scheme for enhancing the resolution of thermal image sequences

In several human activities, such as agriculture and forest management, the monitoring of radiometric surface temperature is key. In particular both high spatial resolution and high acquisition rate are desirable but, due to the hardware limitations, these two characteristics are not met by the same sensor. The fusion of remotely sensed data acquired by sensors with different spatial and temporal resolution is a profitable choice to face this issue. When the real-time requirement is relaxed, the data sequence can be processed as a whole, allowing to improve the final result. Within this framework, we propose a novel batch sharpening strategy, relying on interpolation, data fusion and Bayesi…

Investigating the Relationship between X-Band SAR Data from COSMO-SkyMed Satellite and NDVI for LAI Detection

Monitoring spatial and temporal variability of vegetation is important to manage land and water resources, with significant impact on the sustainability of modern agriculture. Cloud cover noticeably reduces the temporal resolution of retrievals based on optical data. COSMO-SkyMed (the new Italian Synthetic Aperture RADAR-SAR) opened new opportunities to develop agro-hydrological applications. Indeed, it represents a valuable source of data for operational use, due to the high spatial and temporal resolutions. Although X-band is not the most suitable to model agricultural and hydrological processes, an assessment of vegetation development can be achieved combing optical vegetation indices (V…

Un sistema integrato di telerilevamento e modellistica idrodinamica per il monitoraggio delle praterie a Posidonia oceanica

Optimizing the Sampling Area across an Old-Growth Forest via UAV-Borne Laser Scanning, GNSS, and Radial Surveying

Aboveground biomass, volume, and basal area are among the most important structural attributes in forestry. Direct measurements are cost-intensive and time-consuming, especially for old-growth forests exhibiting a complex structure over a rugged topography. We defined a methodology to optimize the plot size and the (total) sampling area, allowing for structural attributes with a tolerable error to be estimated. The plot size was assessed by analyzing the semivariogram of a CHM model derived via UAV laser scanning, while the sampling area was based on the calculation of the absolute relative error as a function of allometric relationships. The allometric relationships allowed the structural …

Analysis of technical criticalities for GIS modelling an Urban noise map

This paper analyzes criticalities and strengthens of a procedure used to model the acoustic map of the vehicular traffic of an urban agglomeration. The research is based on a pilot project for the acoustic mapping of a portion of the city of Palermo (Italy). Simulations indicate that the acoustic climate was in line with expectations and with typical of large Italian cities. The most remarkable result was obtained by an increase in the number of reflections (from two to five), while the influence of the height of the building (from 9 to 18 meters) was negligible – on the order of a few points per thousand. Regarding the analysis conducted with the ‘Gden Method’, acoustic values do not diver…

Effect of morphology on remote sensing-based evapotranspiration assessment at basin scale

CALYPSO: LA RETE RADAR HF PER IL MONITORAGGIO DELLE CORRENTI MARINE SUPERFICIALI NEL CANALE TRA LA SICILIA E MALTA (MAR MEDITERRANEO)

Il canale tra le isole di Sicilia e Malta si trova in una delle principali rotte marittime del Mediterraneo e in una regione strategica per le piattaforme di estrazione petrolifera, quindi seriamente esposta al rischio di eventi di sversamento di idrocarburi in mare. Ciò può costituire una grave minaccia agli ecosistemi locali e alle attività economiche, tra le quali il turismo e la pesca. I danni derivanti da un eventuale sversamento sarebbero incalcolabili per l'arcipelago maltese, dove le risorse marine ed il turismo rappresentano i principali proventi economici e, in maniera analoga, per la Sicilia. Le misure di prevenzione e di mitigazione, insieme a un rapido intervento e a un process…

A post-fire analysis of vegetation dynamics in semi-forested areas using multi-temporal remote sensing imagery

Monitoring agricultural ecosystems

The world’s population is predicted to reach nearly 10 billion by 2050, and at the same time, economic growth and improving living standards in developing countries are driving up food consumption. To accommodate these increasing demands for food, the agricultural sector will need to produce at least 50% more food by 2050. The increasing food production will need to be accomplished not only on degrading soils, with depleting freshwater resources and while experiencing climate change but also sustainably to ensure long-term food and water security. With little existing space to expand current agricultural extents, the increased food production needs to be realized within existing farms throu…

Un modello energetico-idrologico per la stima distribuita dell’evapotraspirazione alla scala di bacino: prime applicazioni

On the Choice of the Most Suitable Period to Map Hill Lakes via Spectral Separability and Object-Based Image Analyses

Technological advances in Earth observation made images characterized by high spatial and temporal resolutions available, nevertheless bringing with them the radiometric heterogeneity of small geographical entities, often also changing in time. Among small geographical entities, hill lakes exhibit a widespread distribution, and their census is sometimes partial or shows unreliable data. High resolution and heterogeneity have boosted the development of geographic object-based image analysis algorithms. This research analyzes which is the most suitable period for acquiring satellite images to identify and delimitate hill lakes. This is achieved by analyzing the spectral separability of the su…

Toward a Comprehensive Dam Monitoring: On-Site and Remote-Retrieved Forcing Factors and Resulting Displacements (GNSS and PS–InSAR)

Many factors can influence the displacements of a dam, including water level variability and environmental temperatures, in addition to the dam composition. In this work, optical-based classification, thermal diachronic analysis, and a quasi-PS (Persistent Scatter) Interferometric SAR technique have been applied to determine both forcing factors and resulting displacements of the crest of the Castello dam (South Italy) over a one-year time period. The dataset includes Sentinel-1A images acquired in Interferometric Wide swath mode using the Terrain Observation with Progressive Scans SAR (TOPSAR); Landsat 8 Thermal Infrared Sensor (TIRS) thermal images, and Global Navigation Satellite System …

Turbidity analysis in Sicilian coastal zones by means of remote sensing images and spectroradiometric measurements

Water turbidity has a wide range of variability both spatially and temporally. Rivers transport sediments to the river mouth following a seasonal behaviour and occasionally during flood events (Doxaran et al., 2006; Pribble et al., 2001). Once in the sea, sediments are spatially driven by currents, and re-suspended by waves from the bottom, changing water turbidity in the tidal and sub-tidal zones (Cloern et al., 1989; Uncles et al., 2002; Wolanski & Spagnol, 2003). Moreover human activities such as transport and dredging occasionally and locally influence turbidity magnitude and distribution (Schoellhamer, 1996). In recent years the pollution of the maritime environment suggests that only …

Soil Water Content Diachronic Mapping: An FFT Frequency Analysis of a Temperature–Vegetation Index

Among the indirect estimation approaches of soil water content in the upper layer of the soil, the &ldquo

A Scan-to-BIM Approach for the Management of Two Arab-Norman Churches in Palermo (Italy)

The paper shows the results of the research activities carried out by the Department of Engineering at the University of Palermo (Italy), which assessed the application of the Heritage Building Information Modelling (HBIM) methodology through a Scan-to-BIM approach to two local churches belonging to the medieval period. This project was motivated by a renewed interest from the city administrators towards the conservation of cultural heritage dating back to the Arab-Norman domination in Sicily since one of the two buildings was included in the UNESCO World Heritage Sites list in 2015. The morpho-typological style of the churches has been acquired by high-detailed 3D surveys, which provided t…

Soil water content assessment: Seasonal effects on the triangle method

Among indirect estimations of the soil water content in the upper layer, the "triangle method" is based on the relationship between the optical and thermal features sensed via Earth Observation. These features are controlled by water content at surface and within root zone, but also by meteorological forcing including air temperature and humidity, and solar radiation. Night and day-time MODIS composite land-surface temperature (LST) allowed applying the thermal admittance version of the method; by taking into account the temporal admittance of the soil, this version was previously found achieving high accuracy in estimate the soil water content at high spatial resolution within a short time…

Assessing actual evapotranspiration via surface energy balance aiming to optimize water and energy consumption in large scale pressurized irrigation systems

Satellite imagery provides a dependable basis for computational models that aimed to determine actual evapotranspiration (ET) by surface energy balance. Satellite-based models enables quantifying ET over large areas for a wide range of applications, such as monitoring water distribution, managing irrigation and assessing irrigation systems’ performance. With the aim to evaluate the energy and water consumption of a large scale on-turn pressurized irrigation system in the district of Aguas Nuevas, Albacete, Spain, the satellite-based image-processing model SEBAL was used for calculating actual ET. The model has been applied to quantify instantaneous, daily, and seasonal actual ET over high- …

Testing two temporal upscaling schemes for the estimation of the time variability of the actual evapotranspiration

Temporal availability of grapes actual evapotranspiration is an emerging issue since vineyards farms are more and more converted from rainfed to irrigated agricultural systems. The manuscript aims to verify the accuracy of the actual evapotranspiration retrieval coupling a single source energy balance approach and two different temporal upscaling schemes. The first scheme tests the temporal upscaling of the main input variables, namely the NDVI, albedo and LST; the second scheme tests the temporal upscaling of the energy balance output, the actual evapotranspiration. The temporal upscaling schemes were implemented on: i) airborne remote sensing data acquired monthly during a whole irrigatio…

Preliminary results of the crustal seismic profile acquired in the frame of the Siripro Project

Forest accessibility, Madonie mountains (northern Sicily, Italy): implementing a GIS decision support system

Valorisation and sustainable exploitation of woody biomass from cultivation interventions might be an important opportunity to track alternative development trails for rural communities in natural protected areas. The governance of Mediterranean protected areas is characterized by overlapping, sometimes conflicting institutions, stakeholders and regulations, causing negative impacts on decision-making processes. We present an open source GIS-based decision support system tool for mapping forest accessibility and optimizing woody biomass extraction. Two models were implemented to support forest managers during the decision-making process in designing and managing wood-energy supply chains. T…

Planktothrix rubescens in freshwater reservoirs: remote sensing potentiality for mapping cell density

Planktothrix rubescens is sadly famous for producing microcystins (MCs), which are powerful hepatotoxins. During the winter 2005/06, P. rubescens has been found in the Pozzillo, Nicoletti, Prizzi and Garcia reservoirs, Sicily; in 2008 it was also detected in SS. Trinita di Delia and Castello reservoirs. Indeed, during periods of low shortwave irradiance such as winter, when light weakly penetrates water column and the water cools, P. rubescens filaments float up to the surface, forming red-colored blooms. Ancillary meteorological measurements highlighted low air temperatures between two frosts in December 2007 and February 2008, with a simultaneous reduction in the incoming total solar radi…

Reservoir monitoring using satellite SAR and GNSS: a case study in southern Italy

Recently, it has been demonstrated that it is possible to relate water levels of a reservoir with its dam displacements. Water levels were determined via remote sensing, while dam displacements were measured via Global Navigation Satellite System (GNSS). Results have shown that displacements and water levels are correlated.Water levels at the Magazzolo reservoir in southern Italy were firstly retrieved using two remote sensing approaches: by visual matching between the reservoir shoreline and contour lines, and by evaluating the surface extent via unsupervised classification to estimate the water levels with an area/depth relation. Dam displacements were measured using GPS receivers on the …

Un confronto tra stime di evapotraspirazione effettiva basate su dati telerilevati in sistemi agricoli e condizioni di stress idrico

Comparison of sensible and latent heat fluxes computed by a surface energy balance algorithm and measured eddy covariance fluxes across rainfall events

Un modello di inerzia termica per la stima del contenuto idrico del suolo da immagini termiche e multispettrali

Robustified smoothing for enhancement of thermal image sequences affected by clouds

Obtaining radiometric surface temperature information with both high acquisition rate and high spatial resolution is still not possible through a single sensor. However, in several earth observation applications, the fusion of data acquired by different sensors is a viable solution for so called image sharpening. A related issue is the presence of clouds, which may impair the performance of the data fusion algorithms. In this paper we propose a robustified setup for the sharpening of thermal images in a non real-time scenario, capable to deal with missing thermal data due to cloudy pixels, and robust with respect to cloud mask misclassifications. The effectiveness of the presented technique…

A thermal inertia model for soil water content retrieval using thermal and multispectral images

Soil moisture is difficult to quantify because of its high spatial variability. Consequently, great efforts have been undertaken by the research community to develop practical remote sensing approaches to estimate the spatial distribution of surface soil moisture over large areas and with high spatial detail. Many methodologies have been developed using remote sensing data acquiring information in different parts of the electromagnetic spectrum. Conventional field measurement techniques (including gravimetric and time-domain reflectometry) are point-based, involve on-site operators, are time expensive and, in any case, do not provide exhaustive information on the spatial distribution of soi…

Sinergia tra mappe di qualità delle acque e correnti superficiali nella determinazione strutture di circolazione

La mappatura delle variabili di qualità delle acque, quali la clorofilla-a (CHL-a) e la Temperatura Superficiale del mare (SST-Sea Surface Temperature) viene effettuata routinariamente dai sensori satellitari per l’osservazione della terra. I satelliti forniscono una visione sinottica di questi parametri, praticamente in tempo reale e su larga scala. Ad ogni modo, le relazioni tra i parametri di qualità delle acque e le forzanti fisiche che ne determinano le variabilità spazio-temporali, quali campi di vento e di correnti, necessitano uno studio approfondito.

Evaluation of different InSAR multi-baseline construction methods over a dam in southern Italy

Monitoring dam displacements using different techniques allows an evaluation of their structural behaviour over time. In this study, dam displacements (for the Castello dam, Agrigento, Italy) have been investigated using different Interferometric Synthetic Aperture Radar (InSAR) techniques exploiting a freely available dataset from the EU Copernicus Sentinel-1 SAR built by the European Space Agency (ESA). The dataset includes Sentinel 1A (S1A) images acquired in dual-polarization and Interferometric Wide (IW) swath using the Terrain Observation with Progressive Scans SAR (TOPSAR) mode. Three main Multi-Baseline Construction methods based on the identification of Persistent Scatterers (PS) h…

COMBINED INTERPRETATION OF ACOUSTIC VELOCITY AND RESISTIVITY MODELS: THE SIRIPRO PROJECT CASE

Monitoring displacements of an earthen dam using GNSS and remote sensing

This paper shows the results of a scientific research in which a GNSS continuous monitoring system for earth-dam deformations has been developed, then, deformations have been related with reservoir water surface and level. The experiment was conducted near Bivona (Sicily, Italy), on the Castello dam (Magazzolo Lake). On the top of the dam three control points were placed and three GNSS permanent stations were installed. The three stations continuously transmitted data to the control centre of the University of Palermo. The former has been determined using freely available satellite data (specifically Landsat 7 SLC-Off) collected during the whole study period (DOYs 101 to 348 2011). Issues r…

Downscaling hydrodynamics features to depict causes of major productivity of Sicilian-Maltese area and implications for resource management

Abstract Chlorophyll- a ( CHL-a ) and sea surface temperature ( SST ) are generally accepted as proxies for water quality. They can be easily retrieved in a quasi-near real time mode through satellite remote sensing and, as such, they provide an overview of the water quality on a synoptic scale in open waters. Their distributions evolve in space and time in response to local and remote forcing, such as winds and currents, which however have much finer temporal and spatial scales than those resolvable by satellites in spite of recent advances in satellite remote-sensing techniques. Satellite data are often characterized by a moderate temporal resolution to adequately catch the actual sub-gri…

An integrated information system for the acquisition, management and sharing of environmental data aimed to decision making

This paper reports the first results of the Project SESAMO - SistEma informativo integrato per l’acquisizione, geStione e condivisione di dati AMbientali per il supportO alle decisioni (Integrated Information System for the acquisition, management and sharing of environmental data aimed to decision making). The main aim of the project is to design and develop an integrated environmental information platform able to provide monitoring services for decision support, integrating data from different environmental monitoring systems (including WSN). This ICT platform, based on a service-oriented architecture (SOA), will be developed to coordinate a wide variety of data acquisition systems, based…

FOTOGRAMMETRIA CONVENZIONALE E SENSORE AD IM-MAGINI “CASI”: APPLICAZIONI ALLA MAPPATURA DELLA VEGETAZIONE SOMMERSA

Obiettivo della ricerca è stato quello di testare l’applicabilità delle tecniche che fanno uso di dati te-lerilevati (multispettrali e da aerofotogrammetria convenzionale) da piattaforma aerea per il monito-raggio delle praterie di Posidonia oceanica. L’analisi multitemporale ha permesso di monitorare l'e-voluzione del “limite superiore” delle praterie sommerse evidenziando l'impatto della pressione an-tropica sulla componente biotica fotoautotrofa dell'ecosistema marino costiero. Dallo studio è emer-so che l'analisi dei dati telerilevati da aereo fornisce un contributo essenziale all’indagine del pae-saggio vegetale a media e piccola scala, consentendo sia un monitoraggio periodico di vast…

Early warnings of Rhynchophorus ferrugineus infestation of Phoenix canariensis: a proximity thermal sensing approach

Phoenix canariensis represents one of the most relevant ornamental plants within Mediterranean environment. In the last few years the infestation of a curculio coleopteron, namely the Rhynchophorus ferrugineus, caused a widespread decimation of these palms. Unluckily damages caused by the insect are evident only in the advanced phase of the disease making futile almost any plant treatment. Early warning of this disease may represents the only way to setup efficient actions to fight the coleopteron in trees where it takes over, thus limiting its spreading in contiguous palms. This research aims to achieve the former result by processing: i) short and long-wave images of the crown acquired du…

A diachronic analysis of estuarine turbidity due to a flood following an extreme rainfall event

During floods following rainfall events characterized by long return period, rivers bring to their mouths the higher concentration of sediments. This paper deals with a qualitative assessment of coastal water and turbidity load in estuarine waters as a consequence of an intense rainfall event occurred on the 16t h and 17 th September 2003 in the eastern part of Sicily. Although empirical relationships to estimate turbidity using remote sensing can be found in literature, however models parameters need to be calibrated through in situ measures acquired via intensive field campaigns. The algorithm used within this research was calibrated using field data acquired during three periods in 2008 …

A sensitivity analysis of a surface energy balance model to LAI (Leaf Area Index)

The LAI is a key parameter in hydrological processes, especially in the physically based distribution models. It is a critical ecosystem attribute since physiological processes such as photosynthesis, transpiration and evaporation depend on it. The diffusion of water vapor, momentum, heat and light through the canopy is regulated by the distribution and density of the leaves, branches, twigs and stems. The LAI influences the sensible heat flux H in the surface energy balance single source models through the calculation of the roughness length and of the displacement height. The aerodynamic resistance between the soil and within-canopy source height is a function of the LAI through the rough…

Soil water content monitoring: a verification of thermal inertia approaches on low spatial, high temporal resolutions images

Soil water content is directly connected with soil evaporation and plant transpiration processes; in particular, soil water content within the root zone, is readily available to evapotranspiration. Thus, in agricultural sciences, the assessment of the spatial distribution of soil water content could be of utmost importance in evaluating crop water requirement. In spite of limitations to applicability due to contingent cloud cover, water content of the upper part of the soil can be determined by applying the thermal inertia approach by coupling optical and thermal infrared images. The thermal inertia formulation, rigorously retrieved on bare soil, has been also verified on soils partially co…

Measurements and Observations in the XXI century (MOXXI) : innovation and multi-disciplinarity to sense the hydrological cycle

ISI Document Delivery No.: FV7JXTimes Cited: 4Cited Reference Count: 249Tauro, Flavia Selker, John van de Giesen, Nick Abrate, Tommaso Uijlenhoet, Remko Porfiri, Maurizio Manfreda, Salvatore Caylor, Kelly Moramarco, Tommaso Benveniste, Jerome Ciraolo, Giuseppe Estes, Lyndon Domeneghetti, Alessio Perks, Matthew T. Corbari, Chiara Rabiei, Ehsan Ravazzani, Giovanni Bogena, Heye Harfouche, Antoine Brocca, Luca Maltese, Antonino Wickert, Andy Tarpanelli, Angelica Good, Stephen Alcala, Jose Manuel Lopez Petroselli, Andrea Cudennec, Christophe Blume, Theresa Hut, Rolf Grimaldi, SalvatoreTaylor & francis ltdAbingdon; To promote the advancement of novel observation techniques that may lead to new so…

Mapping snow density through thermal inertia observations

Snow, as a fundamental reservoir of freshwater, is a crucial natural resource. Specifically, knowledge of snow density spatial and temporal variability could improve modelling of snow water equivalent, which is relevant for managing freshwater resources in context of ongoing climate change. The possibility of estimating snow density from remote sensing has great potential, considering the availability of satellite data and their ability to generate efficient monitoring systems from space. In this study, we present an innovative method that combines meteorological parameters, satellite data and field snow measurements to estimate thermal inertia of snow and snow density at a catchment scale.…

Laboratory Measurements of Flow and Turbulence in Discontinuous Distributions of Ligulate Seagrass

Turbulent flow characteristics were investigated in laboratory flume studies of a ligulate plant canopy interrupted by a gap representing discontinuities observed in seagrass prairies. The reliability of velocity measurements obtained using an acoustic Doppler velocimeter within the canopy was shown using specifically designed experiments. In relatively fast flow (mean velocity 5.5 cm s−1), the mean flow profile was logarithmic above the canopy, had an inflection point near its top, and uniformly low values within it. Within the gap, a recirculation cell formed. Reynolds stress maxima were approximately coincident with the mean flow inflection point. Quadrant analysis revealed an ejection-d…