Physical Oceanography Flashcards
True or false, warm fluid rises and cold sinks?
True
Does fluid move from a low pressure to high or high to low?
Higher pressure to lower pressure
What are the 3 main sources of water circulation?
Wind stress, density differences (temperature, salinity) and tidal movements
What is the Coriolis effect?
Fluid is not attached to the Earth and so does not move in a straight line. As the Earth rotates, fluid is DEFLECTED.
Which way is water deflected in the Northern and Southern Hemispheres?
Northern Hemisphere = deflection to righ
Southern Hemisphere = deflection to left
What are subtropical gyres?
Rotating systems of currents in ocean basins.
Elongated and intensified by Coriolis effect
Water ‘piles’ up at surface.
Why is deep water colder?
Cold currents are denser than warm so sink
What are estuaries?
The connection between freshwater river and marine ocean. Have daily alternations in fresh and seawater.
What are estuaries important for?
Very important habitat for juvenile marine species. Highly productive.
What is the thermocline?
Transition layer between the warmer mixed water at the surface and the cooler deep water below.
What does dimictic mean?
There are two periods during a year where there is full turnover of deep and surface water through vertical mixing and temperature differences are negligible.
When do the two periods of full turnover generally occur?
Spring and Autumn
What is stratification of water influenced by?
Temperature and salinity, resulting in pressure differences
When does stratification of the water column generally occur?
Summer and winter
Why does stratification occur in the summer?
Surface water is warmer than usual due to more sunlight and increased temperature, meaning that deeper waters are cooler
