The ocean in motion
Ocean currents transport warm and cold water over enormous territories. Many of these currents are fundamental to the climate of the areas.
Satellites are important tools for rapid supervision of large ocean areas, surveying current changes and contributing to increased knowledge about the pattern of ocean currents. |
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| The ocean in constant circulation |
| The ocean covers about 71 % of the globe and is therefore very essential to the environment and the life on the Earth. These enormous quantities of water are in constant circulation and transport large quantities of heat and energy from one area to another on the globe, for instance along the coast of Western Norway. |
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| Temperature and salinity decide the density of the water |
| The fresh water of rivers and lakes contains little salt, but in sea water there is so much salt that it may be tasted. The ocean salts consist of 92 substances, but it is primarily sodium (Na+) and chloride (Cl-) also called table salt (Na+Cl-), which, in fact, is extracted from seawater. |
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| How does seawater move? |
| The large systems of ocean currents are first and foremost driven by a combined effect of wind, atmospheric pressure on the surface and the differences of density between various water masses. |
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| The seabed |
| The seabed has at least as great variations in its topography as the landscape above sea level. For the five large oceans the mean ocean depth is 4 000 metres. If we include all ocean areas, the mean ocean depth is 1 200 metres. |
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| Ocean currents |
| The heating from the sun and the differences this involves in terms of temperature, salinity and density, are essential for the ocean currents. |
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| How are ocean currents measured? |
| The speed and the direction of the ocean currents may be measured by a number of more or less technical instruments. |
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| Satellite measurements of ocean currents |
| From the image-forming satellite sensor AVHRR on board the NOAA satellite, it is possible to survey ocean currents by measuring variations in the temperature of the ocean surface. |
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| The North Atlantic current- from the Mexican Gulf to the coast of Norway |
| The climate of Norway and its surrounding areas is considerably warmer than for equivalent areas lying equally far north. |
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| An integrated observation and warning system – field measurements, satellite observations and ocean models |
| The oceans of the world are enormous. Even if one is aiming at supervising only a small part, the challenges are enormous for collecting sufficient information about the state and variation of the ocean. |
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