Search results for " turbidity."
showing 5 items of 5 documents
Coastal zone water quality: Calibration of a water-turbidity equation for MODIS data
2013
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.
Investigating marine shallow waters dynamics to explore the role of turbidity on ecological responses
2009
The ecological tangible effect of the complex interaction between sediments and water column in shallow waters is represented by turbidity which is a common feature of most aquatic ecosystems: it varies both temporally and spatially; it can cover a huge area and persist for a long period or it can be very localized and temporary. Among many factors able to generate turbidity, wind generated wave action and water mass movements due to tides seem important in causing resuspension of sediments. Although there is much research spent in last decades on this topic and many models to explain the complexity of the wind-water-sediment interaction, some interactive aspects are too site specific and t…
Potential Cyclic Steps in a Gully System of the Gulf of Palermo (Southern Tyrrhenian Sea)
2016
Multibeam bathymetric data revealed the occurrence of atrain of bedforms along a gully system in the Gulf of Palermo, Southern Tyrrhenian Sea. The observed gullies, located in the westernmost sector of the Gulf of Palermo, incise the outer shelf at a depth of 120 m and converge at the Zafferano Canyon, connecting to the Palermo Basin at a the depth of 1300 m. Bedforms develop along these gullies and along the thalweg of the canyon, displaying an average wavelength of 200 m, with maximum values of 340 m. Their gully floor location combined with their wave length, upslope asymmetry and crescent shape point to a possible cyclic steporigin of these bedforms. Preliminary numerical modeling sugge…
Monitoring marine water quality of Sicily by means of remotely sensed imagery
2008
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.
Turbidity analysis in Sicilian coastal zones by means of remote sensing images and spectroradiometric measurements
2009
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 …