286
Using hyperspectral data from HyMap and AVIRIS, Khanna et al. (2018) monitored
how water primrose spread over a 12-year period (Fig. 12.6) and showed how it
fundamentally changed biophysical and ecological characteristics of the ecosystem,
including successional pathways.
12.2.3.4 Submerged Macrophytes
Mapping submerged macrophytes and macroalgae presents additional challenges
due to the presence of the water column. Detection of these plants is complicated by
the combined effects of inherent optical properties (IOPs) of the water column,
which are influenced by the diffuse attenuation of the water column itself and the
absorbing and scattering properties of its dissolved and suspended matter, and the
apparent optical properties (AOPs), which are controlled by weather, sun, and sensor view angles (which can lead to sun glint or insufficient signal returns) as well as
the influence of the air-water interface (Mertes et al. 1993; Bostater Jr. et al. 2004;
Morel and Bélanger 2006; Hestir et al. 2008). IOPs are difficult to account for
because water quality and depth can vary spatially and temporally with runoff, geomorphological gradients, meteorological conditions, flow conditions, land use practices, tidal stage, and phytoplankton phenology and community changes (Vis et al.
2003; Nelson et al. 2006; Hestir et al. 2008). Radiative transfer approaches are useful for classifying submerged species. Typically, they use either use model inversion
or look-up tables to solve the radiative transfer model in the water column to distinguish different optically active constituents (e.g., phytoplankton and other pigments,
suspended non-algal particulates, colored dissolved organic matter) and differentiate bathymetry and bottom type (see Odermatt et al. 2012; Giardino et al. 2018 for
Fig. 12.6 Water primrose expansion into open water and submerged vegetation habitat (June 2008
and November 2014) and finally into emergent marsh habitat (October 2016). (Reproduced from
Khanna et al. 2018)
E. A. Bolch et al.
Using hyperspectral data from HyMap and AVIRIS, Khanna et al. (2018) monitored
how water primrose spread over a 12-year period (Fig. 12.6) and showed how it
fundamentally changed biophysical and ecological characteristics of the ecosystem,
including successional pathways.
12.2.3.4 Submerged Macrophytes
Mapping submerged macrophytes and macroalgae presents additional challenges
due to the presence of the water column. Detection of these plants is complicated by
the combined effects of inherent optical properties (IOPs) of the water column,
which are influenced by the diffuse attenuation of the water column itself and the
absorbing and scattering properties of its dissolved and suspended matter, and the
apparent optical properties (AOPs), which are controlled by weather, sun, and sensor view angles (which can lead to sun glint or insufficient signal returns) as well as
the influence of the air-water interface (Mertes et al. 1993; Bostater Jr. et al. 2004;
Morel and Bélanger 2006; Hestir et al. 2008). IOPs are difficult to account for
because water quality and depth can vary spatially and temporally with runoff, geomorphological gradients, meteorological conditions, flow conditions, land use practices, tidal stage, and phytoplankton phenology and community changes (Vis et al.
2003; Nelson et al. 2006; Hestir et al. 2008). Radiative transfer approaches are useful for classifying submerged species. Typically, they use either use model inversion
or look-up tables to solve the radiative transfer model in the water column to distinguish different optically active constituents (e.g., phytoplankton and other pigments,
suspended non-algal particulates, colored dissolved organic matter) and differentiate bathymetry and bottom type (see Odermatt et al. 2012; Giardino et al. 2018 for
Fig. 12.6 Water primrose expansion into open water and submerged vegetation habitat (June 2008
and November 2014) and finally into emergent marsh habitat (October 2016). (Reproduced from
Khanna et al. 2018)
E. A. Bolch et al.