phytoplankton in productive waters). Airborne observations ensure flexible flight
paths that allow observations of unexpected events to be acquired promptly. In this
chapter, we present an overview of remote sensing techniques, by focusing on
imaging spectrometry, for assessing water quality parameters in inland waters such
as lakes, streams, rivers, reservoirs and ponds (defined ‘Case-2 waters’ according to
a traditional remote sensing terminology). Then, we present examples of applications by using airborne Multispectral Infrared and Visible Imaging Spectrometer
(MIVIS) images of Italian inland waters acquired at a spatial resolution varying
from 3 to 5 m. Those examples include the retrieval of water quality parameters
(i.e. chlorophyll-a, suspended particulate matter and coloured dissolved organic
matter), the detection and monitoring of submerged vegetation, the observation of a
cyanobacteria bloom in productive lakes and the investigation of the signal
reflected by floating materials of terrestrial origin (i.e. pollens and oil).
Keywords Airborne • Cyanobacteria • Hyperspectral data • Lakes • Rivers • Water
quality
1 Introduction
Inland natural waters are complex physical–chemical–biological systems including
living and non-living materials that may be present in aqueous solutions or in
aqueous suspensions. Together with air bubbles, foams and scum besides inhomogeneity resulting from small-scale water eddies, these components determine the
bulk optical properties of inland waterbodies [1]. Such a complexity can be optically
defined as ‘Case-2’ waters according to water classification established by Morel
and Prieur [2]. These waters are influenced not just by phytoplankton and related
particles (e.g. organic particles from death and decay of phytoplankton) but also by
other substances introduced from outside the water column that vary independently
from phytoplankton (e.g. resuspension of bottom particles in shallow areas, inorganic and organic suspended matter from land drainages and tributary) [3].
Balance and interaction of water components determines the quality of these
delicate inland water ecosystems, whose quality is threatened by substances and
factors of different origin: for instance, the content of nutrients, suspended particulate matter (SPM) originating from soil erosion, the presence of heavy metals and
pesticides continuously added by anthropogenic sources. The quality of surface
water in lakes, rivers and reservoirs is a major concern around the world. Eutrophication of surface waters from human and agricultural wastes and nitrification of
groundwater from agricultural practices have affected large parts of the world, with
unpredictable consequences on the quality and preservation of ecosystem goods
and services [4].
When deterioration of inland water quality is caused by optically active substances, the effect of these changes can be observed with optical remote sensing
62
C. Giardino et al.
paths that allow observations of unexpected events to be acquired promptly. In this
chapter, we present an overview of remote sensing techniques, by focusing on
imaging spectrometry, for assessing water quality parameters in inland waters such
as lakes, streams, rivers, reservoirs and ponds (defined ‘Case-2 waters’ according to
a traditional remote sensing terminology). Then, we present examples of applications by using airborne Multispectral Infrared and Visible Imaging Spectrometer
(MIVIS) images of Italian inland waters acquired at a spatial resolution varying
from 3 to 5 m. Those examples include the retrieval of water quality parameters
(i.e. chlorophyll-a, suspended particulate matter and coloured dissolved organic
matter), the detection and monitoring of submerged vegetation, the observation of a
cyanobacteria bloom in productive lakes and the investigation of the signal
reflected by floating materials of terrestrial origin (i.e. pollens and oil).
Keywords Airborne • Cyanobacteria • Hyperspectral data • Lakes • Rivers • Water
quality
1 Introduction
Inland natural waters are complex physical–chemical–biological systems including
living and non-living materials that may be present in aqueous solutions or in
aqueous suspensions. Together with air bubbles, foams and scum besides inhomogeneity resulting from small-scale water eddies, these components determine the
bulk optical properties of inland waterbodies [1]. Such a complexity can be optically
defined as ‘Case-2’ waters according to water classification established by Morel
and Prieur [2]. These waters are influenced not just by phytoplankton and related
particles (e.g. organic particles from death and decay of phytoplankton) but also by
other substances introduced from outside the water column that vary independently
from phytoplankton (e.g. resuspension of bottom particles in shallow areas, inorganic and organic suspended matter from land drainages and tributary) [3].
Balance and interaction of water components determines the quality of these
delicate inland water ecosystems, whose quality is threatened by substances and
factors of different origin: for instance, the content of nutrients, suspended particulate matter (SPM) originating from soil erosion, the presence of heavy metals and
pesticides continuously added by anthropogenic sources. The quality of surface
water in lakes, rivers and reservoirs is a major concern around the world. Eutrophication of surface waters from human and agricultural wastes and nitrification of
groundwater from agricultural practices have affected large parts of the world, with
unpredictable consequences on the quality and preservation of ecosystem goods
and services [4].
When deterioration of inland water quality is caused by optically active substances, the effect of these changes can be observed with optical remote sensing
62
C. Giardino et al.