Oceanography Section 2 Flashcards
Section 2
What are deep-water currents driven by
Density differences
Warm vs cold water
Warm water is less dense, has more energy, molecules take up more space. Warm water is in low latitudes, cold in high latitudes
What is salinity
The amount of salt in water. Higher salinity = higher density. Expressed as PSU, meaning 1 part per thousand.
What does precipitation, evaporation, melting, freezing and runoff do to salinity
Precipitation - decrease, Evaporation - Increase , Melting - decrease , freezing - increase, runoff - decrease
How do you measure salinity
You can either measure the electrical conductivity or take the water, evaporate water, measure salt
Where does melting and freezing happen
Higher latitudes
How does precipitation and evaporation happen
When air rises precipitation happens when air sinks evaporation happens
How does runoff happen
depends on the stream flow in the region
How is the salinity in the equator
Average salinity (34-35PSU). Rising air = more clouds but also highest temperature and so precipitation and evaporation happen
how is the salinity in 30 degrees
High salinity (36-37). Warm, air sinks = less clouds. Not much precipitation but a lot of evaporation
how is the salinity in high latitudes
Low salinity (32-33). Cold, low evaporation. much precipitation.
What is thermohaline circulation
Circulation of water caused by density differences and upwelling. Water sinks in the poles and is forced up by upwelling
What is upwelling and downwelling
Upwelling is when water is forced up, downwelling is when water is forced down
Why do animals benefit from upwelling
nutrients sink to the bottom of the ocean so when upwelling occurs those nutrients go to the animals.
What is the mixed layer
The layer at the top of the water. Gets stirred up by wind so temperature and salinity is similar throughout. Exists between both 60N and S. Characteristics rely on latitude
What is the intermediate layer
The layer between mixed and deep. Temp and salinity changes from mixed layer characteristics to meet deep layer’s.
What is the deep layer
Formed at the poles. Cold with low salinity, will always be cold with low salinity.
What is thermocline
when temperature decreases drastically with depth
What is halocline
when salinity decreases drastically with depth
what is pycnocline
when density changes drastically with depth
How can humans and climate change get rid of thermohaline circulation
If water gets warm the density of water decreases and so the water doesn’t sink and so thermohaline circulation can’t happen
