Measurements of the reflectance spectra of reef biota and inorganic substrates
indicate that the dominant types can be distinguished in situ (Knight et al., 1997;
Holden and LeDrew, 1999). In spite of the confounding effect of the overlying water
column (Lee et al., 1994; Holden and LeDrew, 1999, 2001, 2002; Purkis and
Pasterkamp, 2004), this inherent capability for spectral discrimination applies in some
degree to hyperspectral scanners mounted on aircraft flying low enough to minimize
atmospheric contamination (Clark et al., 1997; Gordon and Wang, 1994; Mumby et al.,
2001; Hu and Carder, 2002).
3.5 REMOTE SENSING OF THE REEF SYSTEM ENVIRONMENT
Aside from the control exerted by varying substrate composition, the gross
correlation between benthic metabolic performance and hydrodynamic closure is forced
by associated environmental gradients (Hatcher, 1990; Crossland et al., 1991).
Variation in the benthic light, temperature, and nutrient environments across a reef are
key axes for the determination of E, and are related to hydrodynamic closure, and more
broadly, latitude and land proximity (Crossland et al., 1991).
Low spatial resolution/high temporal resolution (>100 m, <10 days) oceanographic
and meteorological satellite sensors provide capabilities for monitoring the ocean
environment surrounding reef systems (Green et al., 2000; Mazel, 1999). Such
observation of the broader reef environment has also been termed “indirect” remote
sensing, distinct from the “direct” observation of reef substrates (Mazel, 1999). Low
spatial/high temporal resolution satellite sensors (Strong et al., 2000) are a class of
remote sensing instruments distinct from the moderate spatial and temporal resolution
satellite sensors routinely applied to the mapping of reef zonation and intra-zone
biotopes (Andréfouët et al. 2001a; Andréfouët et al., 2003b; Andréfouët et al., 2004).
Designed to serve the oceanographic and meteorological communities, sensors such as
the NASA SeaWiFS (McClain et al., 2004), NASA MODIS (Barnes et al., 2003), and
the NOAA AVHRR (Green et al., 2000) have excellent capabilities to enable the
modeling of environmental forcing variables (Gattuso and Jaubert, 1985; Gattuso et al.,
1993) for models of coral reef benthic metabolism (Andréfouët and Payri, 2001). The
discussion presented below briefly addresses the use of indirect remote sensing in the
modeling of reef system carbon and carbonate metabolism. [The reader is referred to
Chapter 11 (Newman et al.) in this volume for a comprehensive discussion of the
remote sensing capabilities for coastal environmental analysis.]
Meteorological satellite imaging allows the estimation of global or regional surface
irradiance fields, and oceanographic satellite imaging of ocean color provides the
synoptic concentrations of optically active sea water constituents on the same temporal
(daily) time scale. These multiple source satellite-derived products can be combined
within submarine light models to estimate photosynthetically available radiation
through the photic zone and at shallow benthic substrates. Various models for the
estimation of incident solar radiation based on satellite observations and routine
meteorological observations have been developed and evaluated (Bishop and Rossow,
1991; Chertock et al., 1991; Darnell et al., 1988; Dedieu et al., 1987; Frouin et al.,
1988; Pinker and Ewing, 1985). Estimates of downwelling surface shortwave radiation
can now be routinely made at accuracies within 20 W m
-2 on monthly time scales, and
at spatial scales that meet the requirements of reef system biogeochemical modeling
(Pinker et al., 1995).
Algorithms for estimating fluxes of photosynthetically available radiation that rely
on satellite visible wavelength imaging are now used routinely in models of terrestrial
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Coral Reef Ecosystem Process Studies & Remote Sensing
indicate that the dominant types can be distinguished in situ (Knight et al., 1997;
Holden and LeDrew, 1999). In spite of the confounding effect of the overlying water
column (Lee et al., 1994; Holden and LeDrew, 1999, 2001, 2002; Purkis and
Pasterkamp, 2004), this inherent capability for spectral discrimination applies in some
degree to hyperspectral scanners mounted on aircraft flying low enough to minimize
atmospheric contamination (Clark et al., 1997; Gordon and Wang, 1994; Mumby et al.,
2001; Hu and Carder, 2002).
3.5 REMOTE SENSING OF THE REEF SYSTEM ENVIRONMENT
Aside from the control exerted by varying substrate composition, the gross
correlation between benthic metabolic performance and hydrodynamic closure is forced
by associated environmental gradients (Hatcher, 1990; Crossland et al., 1991).
Variation in the benthic light, temperature, and nutrient environments across a reef are
key axes for the determination of E, and are related to hydrodynamic closure, and more
broadly, latitude and land proximity (Crossland et al., 1991).
Low spatial resolution/high temporal resolution (>100 m, <10 days) oceanographic
and meteorological satellite sensors provide capabilities for monitoring the ocean
environment surrounding reef systems (Green et al., 2000; Mazel, 1999). Such
observation of the broader reef environment has also been termed “indirect” remote
sensing, distinct from the “direct” observation of reef substrates (Mazel, 1999). Low
spatial/high temporal resolution satellite sensors (Strong et al., 2000) are a class of
remote sensing instruments distinct from the moderate spatial and temporal resolution
satellite sensors routinely applied to the mapping of reef zonation and intra-zone
biotopes (Andréfouët et al. 2001a; Andréfouët et al., 2003b; Andréfouët et al., 2004).
Designed to serve the oceanographic and meteorological communities, sensors such as
the NASA SeaWiFS (McClain et al., 2004), NASA MODIS (Barnes et al., 2003), and
the NOAA AVHRR (Green et al., 2000) have excellent capabilities to enable the
modeling of environmental forcing variables (Gattuso and Jaubert, 1985; Gattuso et al.,
1993) for models of coral reef benthic metabolism (Andréfouët and Payri, 2001). The
discussion presented below briefly addresses the use of indirect remote sensing in the
modeling of reef system carbon and carbonate metabolism. [The reader is referred to
Chapter 11 (Newman et al.) in this volume for a comprehensive discussion of the
remote sensing capabilities for coastal environmental analysis.]
Meteorological satellite imaging allows the estimation of global or regional surface
irradiance fields, and oceanographic satellite imaging of ocean color provides the
synoptic concentrations of optically active sea water constituents on the same temporal
(daily) time scale. These multiple source satellite-derived products can be combined
within submarine light models to estimate photosynthetically available radiation
through the photic zone and at shallow benthic substrates. Various models for the
estimation of incident solar radiation based on satellite observations and routine
meteorological observations have been developed and evaluated (Bishop and Rossow,
1991; Chertock et al., 1991; Darnell et al., 1988; Dedieu et al., 1987; Frouin et al.,
1988; Pinker and Ewing, 1985). Estimates of downwelling surface shortwave radiation
can now be routinely made at accuracies within 20 W m
-2 on monthly time scales, and
at spatial scales that meet the requirements of reef system biogeochemical modeling
(Pinker et al., 1995).
Algorithms for estimating fluxes of photosynthetically available radiation that rely
on satellite visible wavelength imaging are now used routinely in models of terrestrial
119
Coral Reef Ecosystem Process Studies & Remote Sensing