sS90 Unit 6 Part 1 Atmospheric Stability

The stability of air is determined by measuring the _____ of the atmosphere at various heights.

• Temperature
• Atmospheric layers
• Unstable air
• Stable air

True or False: The most stable conditions occur during a temperature inversion when the temperature decreases with height.

• True 
• False

What is a temperature inversion?

• Environmental lapse rate is less than the wet adiabatic rate
• Environmental lapse rate is greater than dry adiabatic rate
• Environmental lapse rate is equal to adiabatic rates
• The temperature in a layer of air actually increases with altitude

In unsaturated air, as air rises, it cools at 10⁰C/KM. Which lapse rate it refer to?

• Dry adiabatic lapse rate

• Wet adiabatic lapse rate

• Environmental lapse rate

• Normal lapse rate

The picture shows

• Thermal gradient

• Normal conditions

• Thermal inversion

This number tells you the stability of the atmosphere and is a combination of: stability and dryness

• Probability of Ignition

• Relative Humidity

• Haines Index

• LAL

Based on your understanding of unstable air so far, which of the following statements correctly describes its impact on fire behavior. Unstable air _____. Select all that apply

• provides good smoke dispersion and improves visibility on a fire

• increases the inflow of fresh air, thereby promoting the growth of wildland fires and the development of convective columns

• limits smoke dispersion and lowers visibilities on a fire

• often results in increased windspeeds and gusty, erratic winds

Decide if the image above indicates stable or unstable conditions? Select the best answer.

• Stable

• unstable

A thermal belt is best described as

• the top of an inversion where a layer of warm air sits

• a layer of very cold air occurring during an inversion

• a layer of warm air during unstable conditions