Seawater chemical and physical structure - 4 Flashcards
What is insolation?
The amount of sunlight striking Earth’s surface
Why does ocean surface temperature strongly correlate with latitude?
Because insolation decreases with distance from the equator
What is an isotherm?
Contour lines of equal temperature
What direction do isotherms trend?
Generally, east-west except where deflected by ocean currents
What do ocean currents do?
Transport warm water poleward on the western side of ocean basins and transport cold water equatorword on the eastern side of ocean basins
What is a thermocline?
A layer in which water temperature and density change rapidly with depth
How does the thermocline in polar and temperate oceans?
Temperate oceans have a seasonal thermocline whereas polar oceans do not
Where are highest ocean salinities found? Why?
Between 20º and 30º N and S … due to high evaporation rates compared to annual precipitation rates
Where is lowest ocean salinity found? Why?
equator and poleward of 30º … much lower evaporation rates relative to precipitation rates
What is a halocline?
A zone of rapid change in salinity with depth
Where is water stratification most pronounced?
Between 40ºN and 40ºS
The density of seawater is a function of …
Temperature, Salinity, Pressure
What is the pycnocline?
A layer in the water column where water density changes rapidly with depth
What 3 layers can we separate the water column into?
- Surface layer
- Pycnocline
- Deep layer
How thick is the surface layer?
100m
What % of the ocean volume is found in the surface layer?
2%
Why does the surface layer vary seasonally?
Because it is in contact with the atmosphere
What % of the ocean volume does the pycnocline represent?
18%
In low latitudes, the pycnocline coincides with …
A thermocline
In mid-latitudes, the pycnocline coincides with …
A halocline
What % of the deep layer does the deep layer represent?
80%
What is solubility?
The ability of something to be dissolved and go into solution
What is saturation value?
The equilibrium amount of gas dissolved in water at a given temperature, salinity and pressure
Solubility and saturation value for gases in seawater …
increases as temperate and salinity decreases and pressure increases
