The Availability of Timely Global Oceanographic Data from Satellites
5
and the North Pacific, as well as in the Southern Ocean. Cod, salmon, and antarctic
euphausiids have been especially targeted for study.
The published studies and data sets arising from these programs are, of course, only
a fraction of the new material available from which to craft an ecological geography of
the sea. I have reviewed them briefly simply to support my contention that biological
oceanography has evolved in the last 20 years to the extent that what was not possible in
1985 can at least be attempted today.
The Availability of Timely Global
Oceanographic Data from Satellites
Our new ability to specify, using satellite-derived data, a few critical ecological processes under a wide range of ocean conditions, at sites selected to represent characteristic
regions, has far outstripped our ability to describe the distribution, abundance, and
biomass of the biota themselves. Although our accumulated biogeographic data clearly
demonstrate that individual taxa are indeed distributed discontinuously, as will be discussed in Chapter 2, these data are inadequate to partition ecological models among a
series of compartments to represent this discontinuity across the entire surface of the
ocean. Lacking this possibility, global biogeochemical models usually integrate ecological
processes as a parameterized continuum.
However, an ongoing technological revolution now provides the information required
to partition such models realistically, by locating at least some of the partitions in the
ocean to which pelagic ecology is sensitive. During the same period in which WOCE and
JGOFS delivered new understanding in their respective spheres, great advances were made
in the ability of satellite remote sensing systems to deliver high-precision information
at the global scale, describing aspects of the physical and biological state of the oceans.
Time-sensitive mapping of significant relationships between physics and biology in the
pelagic ecosystem is now possible and we can—for the first time—speak seriously about
dynamic observation of ecological processes at global and regional scale. Sensors carried
aboard environmental satellites now routinely obtain data representing conditions at the
surface of the oceans at very short time intervals and specify these at very small spatial
scales. To be sure, nothing is perfect, and data from high latitudes and from regions with
much cloud cover may be inadequate at some temporal scales, but what we have from
the rest cries out for innovative approaches to ecology.
Weather satellites operated by several national agencies deliver data on several important parameters of the sea surface; their scatterometers, altimeters, synthetic aperture
radars, and microwave radiometers deliver information on such characteristics as surface
roughness, elevation, topography, temperature, and upwelling radiation. The TopexPoseidon series of precision radar altimeters deliver sea surface topography, while spectroradiometers from OCI to MODIS measure upwelling irradiance at several wavelengths
from the sea surface and hence “ocean color.” Although only limited information is
obtained at each data point on the ocean surface, the flow of simple data at a resolution of
only a few kilometers, over the whole surface of the ocean, has been revolutionary. These
global products are supported by modeled output representing (for instance) mixed-layer
depth at short time intervals, though this is among the products now unfortunately
hidden behind a security fence.
Sea surface temperature (SST) is obtained with a precision of ±03
K by the Advanced
Very High Resolution Radiometer (AVHRR) instruments carried by the polar-orbiting
US-NOAA environmental satellites, starting with TIROS-N in 1978. The AVHRR is a
scanning spectral radiometer, sensing in the visible, the near-infrared, and the thermal
5
and the North Pacific, as well as in the Southern Ocean. Cod, salmon, and antarctic
euphausiids have been especially targeted for study.
The published studies and data sets arising from these programs are, of course, only
a fraction of the new material available from which to craft an ecological geography of
the sea. I have reviewed them briefly simply to support my contention that biological
oceanography has evolved in the last 20 years to the extent that what was not possible in
1985 can at least be attempted today.
The Availability of Timely Global
Oceanographic Data from Satellites
Our new ability to specify, using satellite-derived data, a few critical ecological processes under a wide range of ocean conditions, at sites selected to represent characteristic
regions, has far outstripped our ability to describe the distribution, abundance, and
biomass of the biota themselves. Although our accumulated biogeographic data clearly
demonstrate that individual taxa are indeed distributed discontinuously, as will be discussed in Chapter 2, these data are inadequate to partition ecological models among a
series of compartments to represent this discontinuity across the entire surface of the
ocean. Lacking this possibility, global biogeochemical models usually integrate ecological
processes as a parameterized continuum.
However, an ongoing technological revolution now provides the information required
to partition such models realistically, by locating at least some of the partitions in the
ocean to which pelagic ecology is sensitive. During the same period in which WOCE and
JGOFS delivered new understanding in their respective spheres, great advances were made
in the ability of satellite remote sensing systems to deliver high-precision information
at the global scale, describing aspects of the physical and biological state of the oceans.
Time-sensitive mapping of significant relationships between physics and biology in the
pelagic ecosystem is now possible and we can—for the first time—speak seriously about
dynamic observation of ecological processes at global and regional scale. Sensors carried
aboard environmental satellites now routinely obtain data representing conditions at the
surface of the oceans at very short time intervals and specify these at very small spatial
scales. To be sure, nothing is perfect, and data from high latitudes and from regions with
much cloud cover may be inadequate at some temporal scales, but what we have from
the rest cries out for innovative approaches to ecology.
Weather satellites operated by several national agencies deliver data on several important parameters of the sea surface; their scatterometers, altimeters, synthetic aperture
radars, and microwave radiometers deliver information on such characteristics as surface
roughness, elevation, topography, temperature, and upwelling radiation. The TopexPoseidon series of precision radar altimeters deliver sea surface topography, while spectroradiometers from OCI to MODIS measure upwelling irradiance at several wavelengths
from the sea surface and hence “ocean color.” Although only limited information is
obtained at each data point on the ocean surface, the flow of simple data at a resolution of
only a few kilometers, over the whole surface of the ocean, has been revolutionary. These
global products are supported by modeled output representing (for instance) mixed-layer
depth at short time intervals, though this is among the products now unfortunately
hidden behind a security fence.
Sea surface temperature (SST) is obtained with a precision of ±03
K by the Advanced
Very High Resolution Radiometer (AVHRR) instruments carried by the polar-orbiting
US-NOAA environmental satellites, starting with TIROS-N in 1978. The AVHRR is a
scanning spectral radiometer, sensing in the visible, the near-infrared, and the thermal