83
satellites such as the US GOES constellation allow continuous mapping of sea surface temperature (SST) at 4 km for the planetary disks in view.
Standard sensor systems aboard US and European operational environmental
(weather) satellites include the Advanced Very High Resolution Radiometer
(AVHRR), providing high-resolution visible, near, and far or thermal IR imagery,
the latter allowing sea surface temperature (SST) retrieval. The European Union’s
ESA European environmental ENVISAT satellite mission (2002–2012) carried a
multispectral visible/ IR scanner (MERIS) together with a wide array of land, ice,
and atmosphere sensors. NASA Earth Observing Mission satellites Aqua and Terra
carry ocean color sensors as well as a variety of other sensors. Currently, operational MODIS instruments measure ocean color in nine bands in the Visible/IR
across a swath width of 2300 km at 1 km resolution. VIIRS, a commercial instrument aboard a NOAA weather satellite, similarly uses nine ocean color bands in the
Visible/IR range over a swath width of 3000 km and a Horizontal Interval on Ground
(i.e., pixel resolution) <1.6 km at the end of the scan, hence considerably better at
nadir. Satellite-borne sea surface temperature (SST) radiometers, ocean color sensors, and sea surface salinity sensors are discussed in greater detail in Chap. 2.
Active instruments aboard dedicated satellites provide imagery ranging from the
fine-scale capability of detecting ship wakes using high-resolution synthetic aperture
radar to the detection of sea surface height anomalies on the order of tens of centimeters due to ocean current gradients and ocean eddies across horizontal ranges of tens
to thousands of kilometers. The Ocean Surface Topography Mission, a joint effort of
NASA, NOAA, CNES, and EUMETSAT, currently operates the Jason-2 satellite in
continuation of the TOPEX/POSEIDON and Jason-1 missions. This satellite transmits microwave pulses to the ocean surface and captures backscattered radiation.
Precise timing and atmospheric corrections allow sea surface height calculation to a
precision of about 5 cm. Such data makes its way into operational coastal ocean
observing since it is incorporated into global circulation models which in turn provide boundary conditions for nested regional and subregional models.
In addition to the primary role of GPS in positioning and navigation, the high
accuracy of the atomic clocks aboard these satellites provides temporal synchronization for a wide range of applications ranging from cellular communication networks to electrical power grids. In ocean observing, land- or buoy-based HF antenna
radar arrays for surface current measurement use this timing for synchronization
between stations to alternate transmit (Tx) and receive (Rx) functions between stations (Lipa et al. 2009), an application termed bistatic operation.
References
Davis RE, Webb DC, Regier LA, Dufour J. The autonomous Lagrangian circulation explorer
(ALACE). J Atmos Ocean Tech. 1992;9:264–85.
Lipa B, Whelan C, Rector B, Nyden B. F Radar bistatic measurement of surface current velocities:
drifter comparisons and radar consistency checks. Remote Sensing. 2009;1:1190–211. https://
doi.org/10.3390/rs1041190.
References
satellites such as the US GOES constellation allow continuous mapping of sea surface temperature (SST) at 4 km for the planetary disks in view.
Standard sensor systems aboard US and European operational environmental
(weather) satellites include the Advanced Very High Resolution Radiometer
(AVHRR), providing high-resolution visible, near, and far or thermal IR imagery,
the latter allowing sea surface temperature (SST) retrieval. The European Union’s
ESA European environmental ENVISAT satellite mission (2002–2012) carried a
multispectral visible/ IR scanner (MERIS) together with a wide array of land, ice,
and atmosphere sensors. NASA Earth Observing Mission satellites Aqua and Terra
carry ocean color sensors as well as a variety of other sensors. Currently, operational MODIS instruments measure ocean color in nine bands in the Visible/IR
across a swath width of 2300 km at 1 km resolution. VIIRS, a commercial instrument aboard a NOAA weather satellite, similarly uses nine ocean color bands in the
Visible/IR range over a swath width of 3000 km and a Horizontal Interval on Ground
(i.e., pixel resolution) <1.6 km at the end of the scan, hence considerably better at
nadir. Satellite-borne sea surface temperature (SST) radiometers, ocean color sensors, and sea surface salinity sensors are discussed in greater detail in Chap. 2.
Active instruments aboard dedicated satellites provide imagery ranging from the
fine-scale capability of detecting ship wakes using high-resolution synthetic aperture
radar to the detection of sea surface height anomalies on the order of tens of centimeters due to ocean current gradients and ocean eddies across horizontal ranges of tens
to thousands of kilometers. The Ocean Surface Topography Mission, a joint effort of
NASA, NOAA, CNES, and EUMETSAT, currently operates the Jason-2 satellite in
continuation of the TOPEX/POSEIDON and Jason-1 missions. This satellite transmits microwave pulses to the ocean surface and captures backscattered radiation.
Precise timing and atmospheric corrections allow sea surface height calculation to a
precision of about 5 cm. Such data makes its way into operational coastal ocean
observing since it is incorporated into global circulation models which in turn provide boundary conditions for nested regional and subregional models.
In addition to the primary role of GPS in positioning and navigation, the high
accuracy of the atomic clocks aboard these satellites provides temporal synchronization for a wide range of applications ranging from cellular communication networks to electrical power grids. In ocean observing, land- or buoy-based HF antenna
radar arrays for surface current measurement use this timing for synchronization
between stations to alternate transmit (Tx) and receive (Rx) functions between stations (Lipa et al. 2009), an application termed bistatic operation.
References
Davis RE, Webb DC, Regier LA, Dufour J. The autonomous Lagrangian circulation explorer
(ALACE). J Atmos Ocean Tech. 1992;9:264–85.
Lipa B, Whelan C, Rector B, Nyden B. F Radar bistatic measurement of surface current velocities:
drifter comparisons and radar consistency checks. Remote Sensing. 2009;1:1190–211. https://
doi.org/10.3390/rs1041190.
References