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Oceanography Lab. Water Masses & How We Study Them. Water Mass. A large volume of water that can be identified as having common origin or source area They sink based on their density Retain their original Temperature Salinity Oxygen (some times). Thermohaline Circulation.
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Oceanography Lab Water Masses & How We Study Them
Water Mass • A large volume of water that can be identified as having common origin or source area • They sink based on their density • Retain their original • Temperature • Salinity • Oxygen (some times)
Thermohaline Circulation • Deep ocean circulation is called thermohaline circulation • Influenced by • Temperature • Salinity • Pressure • Which affect the density of the water mass • Thermohaline circulation is very slow • 1 cm/sec
Determination of Density • Density of seawater is greater than 1 g/cm3, but less than 1.1 g/cm3 • Sigma “t” = σt = (density -1) * 1000 • What is the σt of a water mass of 1.02594 • σt = 25.94
Temperature – SalinityDiagram Water with a salinity of 32‰ (parts per thousand) at a temperature of 10°C has a σt of 24.64 or a density of 1.02464 Every point is this line, called the isopycnal, has a density of 24.00 So if you know the water temperature and salinity you can determine the σt of a water mass What is the σt of a water mass at 2°C with a salinity of 30 ‰?
Caballing • Mixing of two water masses with the same density but different temperatures and salinities • Produces a water mass with higher σt than the previous unmixed water masses.