Chapter 7: APPLICATIONS
of critical importance for extracting useful information about ocean currents
from SAR imagery, since for this case O/2 is comparable to the thickness of
the viscous sublayer.
7.1.5 Microwave imagery
A variety of the oceanic structures such as fronts, meanders, eddies, and
river plumes can be studied using microwave imagery. Figure 7-5 shows a
convergent front on the continental shelf detected by airborne X-band radar
operating in the 2.4-3.8 cm wavelength range. This is an image collected by
Farid Askari (NRL) near Cape Hatteras, NC during the first High Resolution
Remote Sensing Experiment. This converging front (rip) developed at the
shoreward boundary of a Gulf Stream meander and the continental shelf
waters. The red line indicates high backscatter, while the dark blue line
supposedly corresponds to low backscatter due to an accumulation of
surfactants on the north side of the rip.
The appearance of sharp frontal interfaces is usually an indication of an
active subduction process (Chapter 5). Remotely sensed images of sharp
frontal interfaces may therefore potentially contain information about the
vertical structure of the upper ocean.
7.1.6 Monochromatic and color imagery
Monochromatic aerial photography was the first method to trace spatial
structures manifested on the ocean surface. Introduction of color
photography provided wider opportunities for studying and monitoring the
ocean from space.
In addition to photographic methods, non-photographic sensor systems
and space imaging systems have been intensively developing. A significant
advance in sensor technology resulted from subdividing spectral ranges of
radiation into bands (intervals of continuous wavelengths), and allowing
sensors in several bands to form multi-spectral images.
A system for remote sensing of the ocean color consists of a sensor with
a narrow field of view, aimed at a point on the ocean surface (IOCCG,
2000). Special devices allow for the sensor to scan the ocean surface (also
due to the motion of the satellite with respect to the earth surface). The data
acquired from different points on the ocean surface constitute its color
image. The sensor receives radiometric signals in the visible and near
infrared bands of the electromagnetic spectrum. The information content of
the signal depends on the spectral resolution and the number of selected
wavelengths. For example, on the SeaWiFS satellite, several bands cover the
blue, green, and red parts of the visible spectrum and the near infrared range.
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of critical importance for extracting useful information about ocean currents
from SAR imagery, since for this case O/2 is comparable to the thickness of
the viscous sublayer.
7.1.5 Microwave imagery
A variety of the oceanic structures such as fronts, meanders, eddies, and
river plumes can be studied using microwave imagery. Figure 7-5 shows a
convergent front on the continental shelf detected by airborne X-band radar
operating in the 2.4-3.8 cm wavelength range. This is an image collected by
Farid Askari (NRL) near Cape Hatteras, NC during the first High Resolution
Remote Sensing Experiment. This converging front (rip) developed at the
shoreward boundary of a Gulf Stream meander and the continental shelf
waters. The red line indicates high backscatter, while the dark blue line
supposedly corresponds to low backscatter due to an accumulation of
surfactants on the north side of the rip.
The appearance of sharp frontal interfaces is usually an indication of an
active subduction process (Chapter 5). Remotely sensed images of sharp
frontal interfaces may therefore potentially contain information about the
vertical structure of the upper ocean.
7.1.6 Monochromatic and color imagery
Monochromatic aerial photography was the first method to trace spatial
structures manifested on the ocean surface. Introduction of color
photography provided wider opportunities for studying and monitoring the
ocean from space.
In addition to photographic methods, non-photographic sensor systems
and space imaging systems have been intensively developing. A significant
advance in sensor technology resulted from subdividing spectral ranges of
radiation into bands (intervals of continuous wavelengths), and allowing
sensors in several bands to form multi-spectral images.
A system for remote sensing of the ocean color consists of a sensor with
a narrow field of view, aimed at a point on the ocean surface (IOCCG,
2000). Special devices allow for the sensor to scan the ocean surface (also
due to the motion of the satellite with respect to the earth surface). The data
acquired from different points on the ocean surface constitute its color
image. The sensor receives radiometric signals in the visible and near
infrared bands of the electromagnetic spectrum. The information content of
the signal depends on the spectral resolution and the number of selected
wavelengths. For example, on the SeaWiFS satellite, several bands cover the
blue, green, and red parts of the visible spectrum and the near infrared range.
447