At first thought, studying the oceans from space seems to be a bizarre idea.
Space observation helps oceanographers do research with manned and unmanned
space systems. The space systems can be satellites and/or space shuttles that
observe various features of the ocean such as sea-surface winds, sea-surface
temperatures, waves, ocean currents, frontal regions, and sea color.
Technological advances have greatly improved the ability of oceanographers to
gather and use information that is received. Oceanography as viewed from space
has and will become more and more valuable as we begin to understand more of the
world's oceans. Projects Space oceanography uses a number of different sciences
to research the oceans that include physics, geology, biology, chemistry, and
engineering (Cracknell 13). This is evident in the projects that send satellites
into space for observation of our oceans. In 1992, the Topex/Poseidon project
was launched to observe the interaction between the ocean and the atmosphere (Cracknell
17). The Topex/Poseidon mission is to gather information about sea level heights
and ocean currents (Cracknell 17). The Topex/Poseidon orbits above the earth at
840 miles and has a 10-day repeating cycle in which it takes pictures of all of
the earth (Cracknell 17). Information about the how the sea level changes can
tell scientists that there are changes in ocean currents and in climate patterns
(Cracknell 25). This information is valuable to both oceanographers and
meteorologists because it gives information about the phenomena, El Nino. Figure
1 is a picture of how the Topex/Poseidon works. Figure 1(NASA) The Topex/Poseidon
receives information as to what it is supposed to do from a beacon on earth. The
satellite then gathers the information it is supposed to gather and then sends
it to the beacon on earth. The beacon on earth processes this information so
that scientists can use it. As the Topex/Poseidon nears the end of observation
new developments are being made to continue with similar work. Jason 1 is an
observation satellite that will look at extending research about the interaction
of oceans with the atmosphere, improving predictions about the climate, continue
to monitor El Nino, and observe ocean eddies (Cracknell 26). These satellites
are leading the way to a better understanding of our oceans as well as weather
on planet earth. History Observations of oceanographic features with pictures
were first realized with the invention of the camera (Pinet 181). Soon after the
invention of the Camera, hot air balloons were used to take high altitude
pictures of the land and sea, for mapping purposes (Pinet 181). In World War II,
pilots took pictures of large areas of land that were used to develop strategies
in the war (Pinet 181). At the beginning of the space age, just after World War
II, rockets (although never in orbit) used movie cameras to photograph the
surface (Pinet 182). The first manned shuttles took pictures of Earth and
realized there were many observations of the oceans to be made (Pinet 182). Soon
remote sensing came into action as satellites were sent into orbit (Pinet 182).
Process of Remote Sensing Remote Sensing involves two types of instruments,
passive and active (Gautier 58). Passive instruments detect natural energy that
is reflected or emitted from the Sun (Gautier 59). Scientists use a variety of
passive remote sensors such as a radiometer, imaging radiometer, and
spectrometer. A radiometer measures the intensity of electromagnetic radiation
in a band of wavelengths in the spectrum (Gautier 59). The spectrum is a measure
of the visible, infrared (heat), and microwaves emitted from the Earth (Gautier
60). An imaging radiometer has the capability to scan an area and provide pixels
of an area giving more detailed images of the surface than a radiometer (Gautier
60). A spectrometer detects, measures, and analyzes the wavelengths of the
spectrum using prisms to separate the colors (Gautier 61). Active instruments
provide electromagnetic radiation to observe an object (Gautier 69). Satellites
that use active instruments send a pulse of energy towards the object being
observed, then wait for the energy to be reflected (Gautier 69). This energy is
then picked up as weaker or stronger in areas, which can define what features
the satellite is looking at (Gautier 70). Some active instruments are radar,
scatterometer, and lidar (Gautier 71). Radar uses radio or microwaves to emit
electromagnetic radiation upon an object and record the time between when the
energy leaves and comes back (Gautier71). A scatterometer uses microwaves the
same way as radar, but it can measure wind speed and direction (Gautier71).
Lidar uses lasers to transmit a light source on the object being observed, they
can calculate a number of elements in the atmosphere (Gautier 71). With all of
this scientists are able to determine the heights of the oceans, able to predict
weather patterns and the effects on the ocean. Future Unmanned space systems are
the most cost-effective way to observe the planet (Victorov 109). The human eye
however, has the best ability to observe the earth in a visual perspective (Victorov
110). Humans in space play a valuable role in the observation of oceans (Victorov
111). In the future people will be permanently stationed in space stations to
observe and research the earth (Victorov 111). How the satellites work
Satellites that observe the surface of the earth rotate at the same speed as the
earth, this enables them to take pictures from pole to pole (Victorov 123).
Figure 2 is a diagram of a Geostationary Operational Environmental Satellite
(GOES). Figure 2(NASA) A "GOES" satellite rotates above the earth at
22,000 miles. The camera on the satellite sends photographs back to earth
through its antenna (Robinson 34). Solar panels use the sun to produce energy,
and the solar sail and trim tab keep the satellite from spinning out of orbit
when the solar wind hits the satellite (Robinson 34). Ocean color can indicate a
number of things to an oceanographer, such as amount of plankton, and amount of
vegetation (Gautier 117). The color of the ocean changes slightly, from a bright
blue to a dark blue or black (Robinson 118). These changes in color happen when
plankton float freely and concentrate in areas (Robinson 119). These
concentrations are called blooms and are shown off the coast of Angola in Figure
3. Figure 3 The ocean color can also turn into a blue-green because of the
presence of large amounts of vegetation (Robinson 124). Together, these colors
can indicate to scientists the productivity of the oceans and potential for
greater amounts to wildlife (Robinson 125). Figure 4 is a false color image that
shows the amount of plankton in the ocean. Figure 4 The microscopic plankton are
the basis of the marine food web, without plankton all marine life would suffer.
Thus, the importance of the information from the false color images of plankton
on the earth becomes more valuable. Conclusion Oceanography is a new science
that will unleash a lot of new information to us on how planet earth works.
Oceanography from space will be a tool for find out more about our oceans, but
there are limited things it can do. It is expected that few major developments
in oceanography will occur with satellites. The development of satellite
oceanography will bring together ideas from all sciences to an overall
understanding about oceans and earth as a whole.