Earth Science, Tarbuck Chapter 17 Flashcards
What is latent heat
the heat required to convert a solid into a liquid or vapor, or a liquid into a vapor, without change of temperature.
When melting occurs, does latent heat cause heating or cooling
Cooling
When freezing occurs, does latent heat cause heating or cooling
Heating
What is sublimation
conversion of a solid directly to a gas, without passing
through the liquid state
What is vapor pressure
pressure in the air in a saturated environment caused by water vapor
What does it mean when the air is saturated
When the air cannot hold anymore water vapor
What does increasing vapor pressure cause
more water vapor molecules to return to being liquid
What is the mixing ratio
the mass of water vapor in a unit of air compared to the remaining mass of dry air
How to determine mixing ratio
Mass of water vapor /mass of dry vapor
What is Relative humidity
ratio of the air’s actual water-vapor content to the
amount of water vapor required for saturation at that
temperature
A decrease in temperature leads to what reaction in relative humidity levels if water vapor stays constant
relative humidity rises
What happens when water vapor is added but saturation is already at 100 percent
Water condenses
What is the dew point
temperature at which water vapor starts to condense
For every _____ increase in dew-point temperature, air holds about twice as much water vapor
10 Celsius or 18 Fahrenheit
Why does dew often occur during the night?
Temperatures are cooler, dew temperature is cooler, relative humidity is increased
What is adiabatic temperature changes
When air is compressed, the temperature rises. When air is expanded, it cools down. Heat energy is not added or taken away
What is the dry adiabatic rate
Ascending air cools at a constant rate of 10 c for every 1000 meters, and descending air heats at the same rate. Only applies for unsaturated air.
What is the wet adiabatic rate
Ascending air cools at a constant rate of 5 c for every 1000 meters, and descending air heats at the same rate. Only applies for saturated air. Occurs at higher elevations once air reaches dew point and water condenses
Why is the wet adiabatic rate slower than the dry adiabatic rate
Latent heat is released when water condenses
Air tends to _______ vertical movement
resist
4 processes that can cause air to rise
Orographic lifting, Frontal lifting, convergence, and localized convective lifting
What is orographic lifting
elevated terrain, like a mountain range, acts as a barrier to the flow of air, causing it to ascend the mountain and undergo adiabatic cooling
What is a rainshadow desert
When air undergoes orographic lifting, when it reaches the leeward side of the mountain or elevated terrain, most of the water vapor is already lost and it heats adiabatically as it goes down the mountain or elevated terrain.
What is frontal lifting
when warm and cool air masses collide, they create fronts. Cool air acts as a barrier to the warm air, which rises.
What is convergence in air masses
When air masses meet, air escapes upward
What are thermals
air parcels that rise due to being warmer
what is localized convective lifting
When air in a small area is warmed by the sun, it rises
What are sun showers
mid-afternoon rains caused by localized convective lifting
What is stable air
Air that resists upward movement
When does air stop rising
When it reaches an altitude where temperature is equal to that of its surrounding air
What is unstable air
Air that doesn’t stop rising until temperature is equal to surrounding air
What is environmental lapse rate
The rate at which the air temperature changes with height in the atmosphere surrounding a cloud or a rising parcel of air
stable air creates what type of clouds
widespread and little vertical thickness
unstable air creates what type of clouds
towering thunderstorms
What are cloud condensation nuclei
Surfaces for water-vapor condensation at high elevations
What are hygroscopic nuclei
Water absorbing Cloud Condensation Nuclei
3 basic forms of clouds
Cirrus, Stratus, Cumulus
Define Cirrus clouds
clouds that form delicate, veil-like strands. Very thin and light
Define Stratus clouds
clouds consisting of sheets or layers
Define Cumulus clouds
Clouds that consist of globular cloud masses
The term “Nimbus” added to the name of a cloud means what
Cloud is a major producer of precipitation
Composition of High Clouds
Ice crystals or super cooled water droplets
Composition of Middle Clouds
Water droplets or Ice crystals
Composition of low clouds
Water droplets
Cloud types that make up the high cloud family
Cirrus, Cirrostratus, CirroCumulus
What are thermal inversions in air masses
When a warm air mass overlays a cool one, it stops the cooler air mass from rising, trapping pollutants
Middle clouds family
Altocumulus, Altostratus
What does “Alto” mean when added to a cloud
Belongs in Middle Cloud family
Clouds with Vertical Development
Cumulus, Cumulonimbus
Low clouds family
Stratocumulus, Stratus, Nimbostratus
What is fog defined as
Cloud with base at or near the surface
Why does fog dissipate a few hours after sunrise
Fog is evaporated
Different Ways fog can be created
Radiation Fog, Advection Fog, Upslope Fog, Steam Fog, Frontal Fog.
How is radiation fog created
ground cooled by radiation cools surrounding air, leading to it to meet its dew point and water condenses.
How is Advection fog created
Warm, moist air blows over a cold surface, leading to water to condense
How is Upslope Fog created
When an air mass goes up a elevated surface, say a mountain for example, it cools adiabatically and can sometimes form fog
How does steam fog form
When cool unsaturated air moves over a warm body of water,enough moisture may evaporate to saturate the air above, forming fog that rises.
How does frontal fog form
raindrops falling from relatively
warm air above the frontal surface evaporate in the
cooler air below, causing it to become saturated
Water droplets take a long time to drop through the sky, what usually happens to them
Evaporated into unsaturated air
2 processes responsible for precipitation
Bergeron Process and Collision-Coalescence Process
Liquid Water below freezing is called what
Supercooled
Supercooled water does what when in contact of a solid
Freezes
Describe the Bergeron Process
Supercooled water comes in contact with Cloud Condensation Nuclei, freezing. More Super cooled water builds on this frozen ice crystal until it is heavy enough to fall down as snow or rain(if melted).
Describe Collision-Coalescence Process
When warm clouds, where supercooled water is not found, water on hygroscopic nuclei, such as sea salt, form larger droplets, which fall and collide with other small droplets, eventually falling as rain.
Note that Hygroscopic Nuclei is required for this to occur
