Search results for " idrologia"
showing 10 items of 476 documents
Investigating the Relationship between X-Band SAR Data from COSMO-SkyMed Satellite and NDVI for LAI Detection
2013
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…
Time series of Cosmo-SkyMed data for landcover classification and surface parameter retrieval over agricultural sites
2012
This paper reports on the results of an Italian project aimed at investigating the use of X-band COSMO-SkyMed (CSK) SAR data for applications in agriculture and hydrology. Existing classification and retrieval algorithms have been tailored to CSK data and time series of crop, leaf area index and soil moisture maps have been retrieved and assessed through the comparison with in situ data collected over three agricultural sites. In addition, the CSK-derived surface parameters have been integrated into crop growth and hydrologic models and the resulting improvements have been assessed. Results indicate that multi-temporal dual-polarized CSK data are very well-suited for agricultural crop class…
Power sensitivity analysis of multi-frequency, multi-polarized, multi-temporal SAR data for soil-vegetation system variables characterization
2017
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…
Monitoring Water Surface and Level of a Reservoir Using Different Remote Sensing Approaches and Comparison with Dam Displacements Evaluated via GNSS
2018
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…
Thermal inertia modeling for soil surface water content estimation: A laboratory experiment
2012
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…
AN INTEGRATED SYSTEM FOR THE ANALYSIS OF RAINFALL-TRIGGERED LANDSLIDES
2011
La presente ricerca mira a fornire un sistema integrato per l'analisi delle frane attivate da precipitazioni, sviluppando due diverse metodologie: un'analisi statica per l'individuazione delle zone maggiormente propense a produrre scivolamenti (susceptibility mapping) su scala spaziale regionale, ed un'analisi dinamica per la prevision del dove e quando un evento franoso potrebbe veri carsi, ad una scala spaziale di maggior dettaglio . L'analisi statica comporta lo sviluppo di modelli statistici in grado di stimare la probabilità di eventi franosi, sulla base della correlazione tra fattori predisponenti le frane e gli eventi storici. L'esito dell'analisi è la derivazione di una mappa suscet…
FOTOGRAMMETRIA CONVENZIONALE E SENSORE AD IM-MAGINI “CASI”: APPLICAZIONI ALLA MAPPATURA DELLA VEGETAZIONE SOMMERSA
2001
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…
THERMOGRAPHIC CHARACTERIZATION OF A LANDFILL TROUGH AN UNMANNED AERIAL VEHICLE
2019
The use of the thermal imaging camera for Unmanned Aerial Vehicle (UAV) survey is to date very common for environmental analysis, especially if high spatial resolution images are required. Some analyses require images to be acquired close to sunrise, to avoid the influence of the incident solar radiation on the surface temperature, as in the case of a landfill survey. Indeed, thermal anomalies due to generated landfill biogas can be characterized once other heat sources are excluded. In this framework, thermal images need to be processed similarly to optical images by typical photogrammetric workflows producing both a Digital Surface Model (DSM) and an ortho-image. The low spatial resolutio…
Analysis of tide measurements in a Sicilian harbour
2011
Designing of ports and coastal protection works as well as planning of coastal human activities require knowledge of tidal oscillations. The latter vary noticeably from site to site and present an “astronomic” component, which is roughly periodic, and a “meteorological” component which is usually considered as random. In this paper, the tidal oscillations observed in a Sicilian harbour in the period 1999-2009 are analysed statistically, in order to recognize a probability distribution which allows one to predict the highest tidal levels. First, the measurements are used to obtain, for each year, the astronomic tide by the harmonic analysis by the software package T_TIDE. The difference betw…
Comparison between hybrid moving bed biofilm reactor and activated sludge system: a pilot plant experiment
2010
The paper presents the comparison between the traditional activated sludge system (AS) and a hybrid moving bed biofilm reactor (HMBBR). In particular, an experimental campaign has been carried out at the WWTP in Palermo (Italy), on a pilot plant consisting of two pre-anoxic schemes. The aerated tank of the HMBBR line was filled with suspended carriers (AnoxKaldnes™ K1), with a 30% filling ratio. The hydraulic load of the HMBBR line was increased up to two times the AS one. Further, in order to distinguish the additional contribution of the attached biomass for the HMBBR system, in the two lines the Mixed Liquor Suspended Solids (MLSS) was maintained as equal as possible. The monitoring peri…