title: Evaluation of multi-resolution satellite sensors for assessing water quality and bottom depth of Lake Garda.
abstract: In this study we evaluate the capabilities of three satellite sensors for assessing water composition and bottom depth in Lake Garda, Italy. A consistent physics-based processing chain was applied to Moderate Resolution Imaging Spectroradiometer (MODIS), Landsat-8 Operational Land Imager (OLI) and RapidEye. Images gathered on 10 June 2014 were corrected for the atmospheric effects with the 6SV code. The computed remote sensing reflectance (Rrs) from MODIS and OLI were converted into water quality parameters by adopting a spectral inversion procedure based on a bio-optical model calibrated with optical properties of the lake. The same spectral inversion procedure was applied to RapidEye and to OLI data to map bottom depth. In situ measurements of Rrs and of concentrations of water quality parameters collected in five locations were used to evaluate the models. The bottom depth maps from OLI and RapidEye showed similar gradients up to 7 m (r = 0.72). The results indicate that: (1) the spatial and radiometric resolutions of OLI enabled mapping water constituents and bottom properties; (2) MODIS was appropriate for assessing water quality in the pelagic areas at a coarser spatial resolution; and (3) RapidEye had the capability to retrieve bottom depth at high spatial resolution. Future work should evaluate the performance of the three sensors in different bio-optical conditions.
authors.affiliation: National Research Council of Italy, Institute for Electromagnetic Sensing of the Environment, Milano 20133, Italy. giardino.c@irea.cnr.it.
authors.forename: Claudia
authors.initials: C
authors.lastname: Giardino
authors.affiliation: National Research Council of Italy, Institute for Electromagnetic Sensing of the Environment, Milano 20133, Italy. bresciani.m@irea.cnr.it.
authors.forename: Mariano
authors.initials: M
authors.lastname: Bresciani
authors.affiliation: National Research Council of Italy, Institute for Electromagnetic Sensing of the Environment, Milano 20133, Italy. cazzaniga.i@irea.cnr.it.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Cazzaniga
authors.affiliation: Earth Observation and MAPping GmbH & Co.KG, Seefeld 82229, Germany. schenk@eomap.de.
authors.forename: Karin
authors.initials: K
authors.lastname: Schenk
authors.affiliation: Earth Observation and MAPping GmbH & Co.KG, Seefeld 82229, Germany. rieger@eomap.de.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Rieger
authors.affiliation: National Research Council of Italy, Institute of Marine Sciences, Venezia 30122, Italy. federica.braga@ve.ismar.cnr.it.
authors.forename: Federica
authors.initials: F
authors.lastname: Braga
authors.affiliation: National Research Council of Italy, Institute for Electromagnetic Sensing of the Environment, Milano 20133, Italy. matta.e@irea.cnr.it.
authors.forename: Erica
authors.initials: E
authors.lastname: Matta
authors.affiliation: National Research Council of Italy, Institute for Electromagnetic Sensing of the Environment, Milano 20133, Italy. brando.v@irea.cnr.it.
authors.forename: Vittorio E
authors.initials: VE
authors.lastname: Brando