2 Flashcards
What do we mean by shortwave radiation?
Radiation from the sun, also called solar radiation
What is attenuation of light?
Reduced intensity of solar radiation due to light scattering and absorption
What is the connection between attenuation of light and heating of surface water?
Absorption transfers radiation into heat
How does a large attenuation coefficient affect heating of the ocean?
A large attenuation coefficient means rapid attenuation with depth, and thus much absorption that transfers radiation into heat.
Why is the ocean blue?
Blue light penetrates the deepest in a clear ocean. Blue light is scattered most and absorbed the least. Therefore both the sky and the ocean are blue.
What makes sound propagate?
Sound propagates as pressure waves utilizing compressibility of the medium it propagates in. Larger compressibility means slower sound propagation speed.
How does the sound speed depend on temperature and pressure?
Sound speed decreases with decreasing temperature, but increases with increasing pressure.
What do we mean by net surface heat flux?
The sum of the four different types of heat fluxes exchanging heat across the ocean surface; the difference between fluxes that heats the ocean and fluxes that cools the ocean.
What are the four different types of surface heat flux?
- Solar radiation (shortwave radiation) 2. Longwave radiation (infrared) 3. Latent heat flux (evaporation/ice melting) 4. Sensible heat flux (heat conduction)
Which factors influence solar radiation?
Solar noon altitude, surface albedo, clouds and water vapor in the atmosphere.
Which factors influence longwave radiation?
Ocean surface temperature, clouds and water vapor in the atmosphere.
Which factors influence latent heat flux?
Degree of saturation of water vapor in the air near the ocean surface, and wind speed near the ocean surface.
Which factors influence sensible heat flux?
Temperature difference between the ocean surface and in the air near the surface, and wind speed near the ocean surface.
What is Molecular diffusion?
Spreading of a compound from high concentration towards low concentration (down-gradient diffusion)
Explain molecular viscosity and diffusion
Random movement of water molecules act as friction on currents (viscosity) and
spread properties of the water (diffusion).
What is the difference between turbulent and molecular viscosity and diffusion?
Internal friction and spreading due to molecular movement or turbulent movement.
Turbulent diffusion/viscosity is much faster than molecular diffusion/viscosity.
What in principle is the Kolmogorov length scale?
The smallest size of whirls in turbulence. Below this length scale turbulence is dissipated into heat.
Why is vertical (diapycnal) eddy diffusion generally smaller than horizontal (isopycnal) eddy diffusion?
Stability inhibit vertical movement, reducing the vertical size of whirls in turbulence.
What generates eddies and turbulence?
Generally a vertical or horizontal current shear, often between density layers.
What does the Richardsons number tell us?
The relative strength between the stability restoring force and the turbulence generation force (current shear). If the number is small, the flow is turbulent.
What do we mean by steady state?
A property of the fluid inside a specific volume is in steady state of its value does not change with time
What is the principle behind Knudsen’s relations?
Knudsen’s relations combines conservation of salt and conservation of volume in a basin with freshwater supply and water exchange with an adjacent ocean.
