Stratification Flashcards
What mathematical concept is used to describe stratification?
Stratification is described mathematically through density differences (∆ρ = ρ1 - ρ2).
What happens when stratification increases?
adds stability to water column.
What does stable mass distribution do in a stratified ocean?
resists vertical motion.
What is Brunt-Väisälä frequency (N) used for?
N quantifies stratification by measuring natural oscillation resulting from vertical displacement.
What indicates strong stratification according to Brunt-Väisälä frequency?
A large N indicates strong stratification and high stability.
What occurs during the mixing process in the ocean?
Mixing raises center of mass of water column and converts kinetic energy into potential energy.
What are the main layers mentioned in the ocean’s vertical structure?
The main layers are the thermocline, halocline, pycnocline, and mixed layer.
What is the importance of the surface mixed layer?
crucial for air-sea exchange and tropical cyclone development.
What characterizes the typical vertical structure of the open ocean?
It features a warmer, lighter upper mixed layer and a cooler, heavier lower stratified layer.
What can stratification block from mixing?
gases, nutrients, and heat between surface layer and deep ocean.
How does solar heating affect stratification?
Increased solar radiation reduces surface density, leading to increased stratification.
What seasonal changes impact mixed layer depth?
Winter leads to maximum mixed layer depth due to wind stirring and cooling, while summer results in thinner mixed layers.
What does the density anomaly in mixed layer depth refer to?
It refers to long-term averages of density differences in the mixed layer.
What role does wind mixing play in the mixed layer?
deepens mixed layer by entraining fluid from below.
How does buoyancy loss due to cooling/evaporation affect the mixed layer?
causes dense water at the surface to become unstable, leading to mixing.
What happens when buoyancy gain from heating/precipitation occurs in the mixed layer?
stabilizes surface water, can make the mixed layer shallower.
Why does mixing create a stair-step pattern in density and temperature profiles?
Multiple episodes of heating, cooling, and mixing contribute
What is an effect of tropical cyclones on the mixed layer?
significant storm-driven mixing, which deepens the pycnocline.
How can long-term seasonal stratification affect biological production?
Seasonal stratification controls biological production cycle due to impact on temperature and density gradients.
What happens to the mixed layer at the end of winter?
deepens to maximum thickness due to erosion of stratification.
What are the characteristics of an unstable density distribution?
vertical motion within water column.
What is a key characteristic of the neutral state in stratification?
density has no influence on vertical motion.
How is the mixed layer affected by diurnal heating?
Diurnal heating can lead to variability in mixed layer depth due to the difference between daytime heating and nighttime cooling.
What is the effect of storm timing on mixing efficiency?
The timing of storms, especially in seasonally stratified shelves, can affect the efficiency of storm-driven mixing.
