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The mass per unit volume of a substance. Th oceanographic shorthand for density is "sigma-t".
Density is weight divided by the amount of space it occupies. Density can be expressed as kilograms per cubic meter (mass divided by volume). For instance, if a cubic meter (~264 gallons) of seawater weighs 1025 kg (~1 ton), it has a density of 1025 kg/m 3 . Another way you will see density expressed is as sigma-t, which is simply the density minus 1000. Seawater with a density of 1025 kg/m 3 has a sigma-t of 25. Seawater density is directly related to the salinity and temperature of seawater.


(1) Climate change (3) Oceanic primary productivity
(2) Ocean circulation (4) Air-sea heat exchange


Microwave (1.26, 1.41 GHz)

Platforms and Sensors

Platform Sensor
Aquarius ( launch September 2008) To be determined

Other sources for data

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Last updated: Oct 13, 2009 01:41 PM ET