Stability Flashcards
What is a stable situation?
A small change is resisted and the system returns to it’s previous state
What is a neutral situation?
A small change is neither resisted nor enlarged
What is an unstable situation?
A small change initiates a bigger change
What does adiabatic mean?
No heat input or output
What happens to a parcel of air as it expands without heat input from the surroundings?
It’s pressure and temperature drop and it’s volume increases
What is enviromental lapse rate?
The temperature change with height in the atmosphere.
How is the stability of air detemined?
By comparing the enviromental lapse rate to the dry and moist adiabatic lapse rates
What does temperature inversion mean?
Icreasing temperature with height
How do stable conditions come about?
Formed by cooling of lower air layers
How do unstable conditions come about?
Formed by warming of lower air levels
What is fumigation?
With warming near ground level, downward mixing takes place, confining the smoke emissions to a narrow layer
What is looping?
In unstable conditions, the plume rises and falls as light winds take it away. If this happens without too much dispersion of pollutants, the plume follows a looping path.
What is coning?
In neutral conditions, the enviromental lapse rate equals the dry adiabatic lapse rate and the plume spreads up and down about equally without turbulence
What is lofting?
Stable air near the ground and unstable air aloft gives no downward mixing and the best conditions for sending plumes upwards
What are the four main processes leading to cloud formation?
Convection,
Topographic lifting,
Convergence,
Uplift along weather fronts
