Claudia Giardino - Academia.edu (original) (raw)

Papers by Claudia Giardino

Remote Sensing for Agriculture, Ecosystems, and Hydrology, 1998

ABSTRACT

Italian Journal of Remote Sensing, 2009

Journal of Applied Remote Sensing, 2007

ABSTRACT Temporal variation in the extent of submerged macrophytes along the littoral zone of Sir... more ABSTRACT Temporal variation in the extent of submerged macrophytes along the littoral zone of Sirmione Peninsula in the southern part of Lake Garda (Northern Italy) was investigated using imaging spectrometry. Two images, with a spatial resolution of 5 m were acquired by the Multispectral Infrared and Visible Imaging Spectrometer (MIVIS) in the summers of 1997 and 2005. Image data were first geocoded and then corrected for both atmospheric and skylight reflection effects at the water surface using the 6S radiative transfer code. The two images were inverted using a bio-optical model, which was parameterised with the inherent optical properties of the lake. The inversion utilized the spectral range from 0.48-0.60 mu m because it simultaneously provided the lowest environmental noise and the best atmospheric correction performances for the two scenes and produced images of bottom depth and of two substrate classes: bare sand and submerged vegetation, representing a mixture of valuable freshwater species. The MIVIS-derived bottom depth ranges and patterns were comparable to a bathymetry chart with a deviation less than 5%. In 2005, the image was consistent with contemporaneous in-situ derived knowledge on macrophyte distribution. In 1997, the substrate image map was deemed reasonable with respect to the macrophyte distribution documented in 2000. The comparison of the substrate products for the two dates showed a marked decrease in macrophyte beds, with a concomitant increase in sandy substrates. In the 8-year interval the extent of submerged macrophyte decreased from 72% to 52%. We expect that this study will contribute to increased knowledge of macrophyte colonisation patterns of the Sirmione Peninsula, where, despite their ecological significance, changes have been poorly documented.

Remote Sensing of Environment, 2007

For testing the integration of the remote sensing related technologies into the water quality mon... more For testing the integration of the remote sensing related technologies into the water quality monitoring programs of Lake Garda (the largest Italian lake), the spatial and spectral resolutions of Hyperion and the capability of physics-based approaches were considered highly suitable. Hyperion data were acquired on 22nd July 2003 and water quality was assessed (i) defining a bio-optical model, (ii) converting

Extensions of submerged macrophyte and their variation in time along the littoral zone of Sirmion... more Extensions of submerged macrophyte and their variation in time along the littoral zone of Sirmione Peninsula, in the southern part of Lake Garda (Northern Italy), were investigated from imaging spectrometry. Two images with a ground resolution of 5 m were acquired by the Multispectral Infra- red and Visible Imaging Spectrometer (MIVIS) during summer 1994, 1997, 2000 and 2005. Image data

The successful launch of MERIS in March 2002 has given a great opportunity to understand the chan... more The successful launch of MERIS in March 2002 has given a great opportunity to understand the changes of water colour with high temporal and spatial resolutions. In this study, potentials of MERIS sensor were investigated to describe variations of optically active substances of Lake Garda. The basin is located in the Italian sub-alpine lacustrine district, where several other lakes and

Noisy spectra were simulated from laboratory 2000-2500 nm reflectance spectra of polymineralic sa... more Noisy spectra were simulated from laboratory 2000-2500 nm reflectance spectra of polymineralic sand samples and synthetic composite spectra, using MIVIS calibration parameters and measured solar irradiance both with and without diffuse atmospheric radiance at the sensor. Noise content variation in output data with varying sensor parameters and atmospheric conditions was analysed, as well as noise effects in spectral feature identification.

article i nfo Traditional methods for aerosol retrieval and atmospheric correction of remote sens... more article i nfo Traditional methods for aerosol retrieval and atmospheric correction of remote sensing data over water surfaces are based on the assumption of zero water reflectance in the near-infrared. Another type of approach which is becoming very popular in atmospheric correction over water is based on the simultaneous retrieval of atmospheric and water parameters through the inversion of coupled

MERIS (A) ATSR …, 2005

... First name dot last name at hut dotfi 2. Finnish Environment Institute P0 BOX 140, SF-00251 H... more ... First name dot last name at hut dotfi 2. Finnish Environment Institute P0 BOX 140, SF-00251 Helsinki, FINLAND ... For this campaign 32 channels that match the MODIS (EQS Terra and Aqua satellites) and MERIS channels in the wavelength range 437-89 1 nm were selected. ...

International Journal of Remote Sensing, 2003

The Science of the total environment, 2001

Remote Sensing of Environment, 2010

International journal of oral …, 1994

During 1975-87, 105 patients with squamous cell carcinoma (SCC) of the lip were surgically treate... more During 1975-87, 105 patients with squamous cell carcinoma (SCC) of the lip were surgically treated. All patients underwent radical resection of the tumor. Only the patients with palpable lymph nodes had a simultaneous neck dissection. All patients were followed up for at least 5 years. Of the 80 patients without palpable lymph nodes, only three developed lymph-node metastasis. Of the 25 patients with palpable lymph nodes who underwent modified neck dissection, four had recurrence of lymph-node metastasis at a different level. The over-all 5-year survival rate was 97%. The survival rate for patients with lymph-node metastasis was 88%.

ABSTRACT The Curonian Lagoon, the largest in Europe (total surface area 1584 km2), is located in ... more ABSTRACT The Curonian Lagoon, the largest in Europe (total surface area 1584 km2), is located in the southern part of the Baltic Sea, from which it is separated by a narrow sand bar and to which it is connected by the Klaipeda Straits. It is characterised by shallow eutrophic waters (mean depth 3.8 m) with average low salinity (<5‰) due to the nutrient-rich freshwaters discharged by the river Nemunas. Cyanobacteria blooms, including species producing toxic metabolites, have been a frequent phenomenon in summer. In this study a series of MERIS Full Resolution (FR) satellite images acquired between 2004 and 2009 during summer periods were used to assess the temporal evolution and spatial variability of the lagoon water quality in terms of chlorophyll-a. The models/algorithms were calibrated/validated with field data collected in 2009, based on in situ radiometric (remote sensing reflectance -Rrs-) and limnological (chlorophyll-a concentrations -chl-a-) measurements. The chl-a concentrations were estimated by developing a semi-empirical band ratio (Rrs(708)/Rrs(664)) equation applied to MERIS images after correction for atmospheric effects with the 6S code. Results from this study suggest elevated spatial and temporal variability of chl-a. Spatial variability probably arises from the mosaic of situations within the Curonian lagoon in terms of bottom sediment features, nutrient availability in the water column, water depth and hydrodynamics. Temporal variability is probably linked to complex and interplaying metereological and environmental constraints such as the length of the ice cover period, average water temperatures, wind-induced sediment re-suspension, the pattern of precipitations and river-associated nutrient transport to the lagoon. This study stresses the importance of remote sensing as a valid tool for long-term whole ecosystem studies. The preliminary results need more through analyses and intersection with other environmental data in order to better comprehend algal bloom determinants in complex and extremely dynamic systems such as coastal lagoons.

ABSTRACT In this study we present calibration/validation activities associated with satellite MER... more ABSTRACT In this study we present calibration/validation activities associated with satellite MERIS image processing and aimed at estimatingchl a and CDOM in the Curonian Lagoon. Field data were used to validate the performances of two atmospheric correction algorithms,to build a band-ratio algorithm for chl a and to validate MERIS-derived maps. The neural network-based Case 2 Regional processor wasfound suitable for mapping CDOM; for chl a the band-ratio algorithm applied to image data corrected with the 6S code was found moreappropriate. Maps were in agreement with in situ measurements.This study confirmed the importance of atmospheric correction to estimate water quality and demonstrated the usefulness ofMERIS in investigating eutrophic aquatic ecosystems.

The Science of the total …, 2001

Some bio-physical parameters, such as chlorophyll a concentration, Secchi disk depth and water su... more Some bio-physical parameters, such as chlorophyll a concentration, Secchi disk depth and water surface temperature were mapped in the sub-alpine Lake Iseo (Italy) using Landsat Thematic Mapper (TM) data acquired on the 7 March 1997. In order to adequately investigate the ...

... [4] Ruiz-Verdu, R., S. Koponen, T. Heege, R. Doerffer, C. Brockmann, K. Kallio, T. Pyhälahti,... more ... [4] Ruiz-Verdu, R., S. Koponen, T. Heege, R. Doerffer, C. Brockmann, K. Kallio, T. Pyhälahti, R. Pena, A. Polvorionos, J. Heblinski, P. Ylöstalo, L. Conde, D. Odermatt, V. Estelles and J. Pulliainen. Development of MERIS lake water algorithms: Validation results from Europe. ...