Chapter 7 Flashcards
What is evaporation?
The phase change of a liquid to a gas
Define transpiration.
The transfer of water into the air via leaf pores or stomata
What does humidity measure?
The water vapor content of the air
What is saturation?
Holding all the moisture it can
What is specific humidity?
The weight of water vapor in the air per unit weight of air, which includes the weight of water vapor
Define mixing ratio.
The weight of water vapor per unit weight of dry air
What is vapor pressure?
The partial pressure created by water vapor
What is saturation vapor pressure?
The pressure that water vapor creates when the air is fully saturated
Define relative humidity.
The ratio of the amount of water vapor in the air to its saturation point
What is condensation?
The phase change of water vapor into a liquid
What are condensation nuclei?
Act as a platform for condensation to take place, increasing the size of a droplet and decreasing surface tension
What is dew?
Small droplets of water that form as a result of condensation
Define fog.
A cloud that forms near the ground
What is radiation fog?
Forms during the evening under cloudless skies and with little to no wind
What is steam fog?
Occurs when cool dry air settles over a warm, moist surface
Define advection fog.
Forms when warm and moist air travels over a cool surface
What is upslope fog?
Forms when moist air is forced up a slope
What is frontal fog?
Associated with weather fronts, especially a warm front
What is the saturated adiabatic rate?
If the air is saturated, the rate of temperature change is .6 C/100 meters
What is the dry adiabatic rate?
If the air is dry, the rate of temperature change is 1 C/100 meters
Define stable air.
Stable atmospheric conditions prevail when the environmental lapse rate is less than the saturated adiabatic rate
What is unstable air?
Air is unstable when the environmental lapse rate is greater than the dry adiabatic rate
Describe a cirrus cloud.
Appear as wispy thin veils or detached filaments composed mostly of ice
What is a cirrostratus cloud?
A transparent, whitish veil of cloud that usually covers much of the sky
Define altostratus.
Formless layer of grayish cloud that cover most if not all the sky
What are stratus clouds?
Appear as a uniform dark-gray layer of clouds covering the entire sky
Describe cumulus clouds.
Appear as small, cotton ball-like clouds that generally form by convection
What is a nimbostratus cloud?
Dark-gray layer of clouds that cover the entire sky; the prefix ‘nimbo’ indicates that these clouds are precipitating
Define cumulonimbus clouds.
Form during very unstable conditions
What is a phase change?
The transition of a substance from one state of matter to another
