Week 5 ICCR

Inversion

A layer of air in which the temperature increases with height

Is it easy or hard for molecules to mix in an inversion?

Hard

What does an inversion act like?

The lid on a jar. It closes off that air from new molecules entering it

T/F: Pollutants have weight

True

How can you find the concentration of pollutants that mixed into air?

Dividing the mass of the polltant by the mass of the air it mixes into

When there is not inversion, what is the mixing called?

Unconfined mixing

What is unconfined mixing?

Mixing that happens in air that is not closed from inversion

What is the dispersion coefficient?

Lets us know how fast and what material will diffuse into the atmosphere

How do we get a rough estimate of the dispersion coefficient?

Estimate the size of the eddies and the speed at which they turn over in a turbulent atmosphere

Why is the dispersion coefficient only used in unconfined mixing?

Because there is no mixing in inversion

What is really important in unconfined mixing?

Time (think of tea bags diffusing)

The longer you wait the _______ dilute an area will be

more

What is turbulent dispersion?

The diffusion of material being very fast at first then slowing down

What is plume?

The collection of pollutants/materials that wind blows around

What two factors change the amount of pollutant that a plume can give off somewhere?

Wind direction and distance

What is lapse rate?

The rate of change of temperature with height

What is the typical lapse rate?

-6.5 degrees Celsius per kilometer

During inversion, is lapse rate positive or negative?

Positive since there is a positive correlation between increase in height and increase in heat/temp

What does adiabatic lapse rate mean?

The rate of cooling as a parcel of air rises

What is a stable environment?

Air and the environment around it interact with each other so the temperature remains constant

In a stable environment, if a parcel is lifted upward, what does it want to do?

Sink back down since it is denser

T/F: The environment is usually in a stable state

True

What is adiabatic lapse rate?

The rate of cooling as a parcel of air rises

Two possible things that may happen to molecules are Inversion or Unconfined Mixing. Please compare and contrast these two.

Inversion occurs when there is a layer of air in which the temperature increases with height and the air is “closed”. Inversion is like a lid on a jar and it keeps molecules from mixing together. Conversely, unconfined mixing occurs when air is not closed like it would be in inversion, meaning molecules can more easily mix together

Which of the following is not true about the dispersion coefficient?

a) It can help tell us how fast added material will diffuse

b) It is represented by the symbol K

c) It is only used in unconfined mixing

d) It can be used for inversion, when there is no unconfined mixing

D

The Lapse rate is the rate of change of ______ with _______

Temperature, height

________ dispersion if the diffusion of materials being bery fast at first then slowing down

Turbulent

What is the unit of measurement for lapse rate?

degrees celsius per meter

What does adiabatic mean?

Not adding heat