Thermal stratification
- Refers to horizontal separation of a relatively warmer surface layer of water from the cooler bottom waters.
- It occurs when differences in density of upper and lower strata become so great that the two strata can’t be mixed by wind.
- The upper stratum is called epilimnion and the lower stratum the hypolimnion.
- The stratum between the epilimnion and hypolimnion which has a marked temperature differential is termed as metalimnion or thermocline.
- The reverse process of mixing of all three layers is termed as destratification or overturns.
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Epilimnion |
Hypolimnion |
Metalimnion |
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Characterized by high temperature per unit depth, low density and gradual decrease in temperature pepr unit depth. |
Characterized by low temperature, high density and gradual decrease in temperature per unit depth. |
Characterized by layer of moderate temperature and density, and abrupt decrease in temperature per unit depth. |