2 1A collection of small water droplets or ice crystals falling slowly through the air a(n)Cloud
3 2The crystals or droplets that make up clouds form when condensation or sublimation occurs more quickly than the process of:Evaporation
4 3A cloud that forms near or on Earth’s surface is:Fog
5 4 What must be available for water vapor to condense and form a cloud? A solid surface
6 5The lowest layer of the atmosphere is thetroposphere
7 6What is present in the troposphere that is essential for cloud formation?Tiny suspended particles
8 Dust from Africa's Saharan Desert lingers in high altitudes as it crosses the Atlantic Ocean. This picture was taken from an aircraft northeast of Barbados in Cumulus clouds can be seen poking through the tops of the dust layer, which is seen as a milky white haze.
9 7Suspended particles that provide a surface for water vapor to condense are calledCondensation nuclei
10 8 What happens when water molecules collect on condensation nuclei? Water droplets form
11 9 What condition must the air be in for clouds to form? The rate of condensation must be higher than the rate of evaporation.
12 10 The net condensation that forms clouds may be caused by The cooling of air
13 11What happens to molecules in rising air?They move farther apart.
14 12 What occurs in adiabatic cooling? The temperature of an air mass decreases as the air rises.
15 13 What does the adiabatic lapse rate describe? The rate at which the temperature of rising or sinking air changes
16 14 What is the adiabatic lapse rate of clear air? -1oC for every 100m that air rises
17 15 What is the average adiabatic lapse rate of cloudy air? Between -0.5oC and -0.9oC per 100 m that air rises
18 16 Why does cloudy air have a slower rate of cooling than clear air? Because of the release of latent heat as water condenses.
19 17What two things happen to the energy from the sun when it reaches Earth’s surface?Earth’s surface absorbs it and then reradiates it as heat
20 18 Describe what happens to air near Earth’s surface. It absorbs heat, it rises, expands, and then cools
21 19What is the name of the altitude where net condensation begins to form clouds?Condensation level
22 20How does the mixing of two bodies of moist air with different temperatures cause clouds to form?The combination causes the temperature of air to change. The combined air may be cooled to below its dew point, which results in clouds.
23 21 What are the results of air being forced upward? The cooling of the air and cloud formation.
24 22 What kind of terrain may force air upward? Sloping terrain, such as a mountain range
25 23 How do large clouds associated with storm systems form? As a mass of cold, dense air enters an area and pushes a less dense mass of warmer air upward.
26 24What is the name of the process in which the temperature of an air mass decreases as it moves over a cold surface, such as cold ocean or land?Advective cooling
27 25What happens when an air mass moves over a surface colder than the air is?The cold surface absorbs heat from the air and the air cools.
28 26What must happen in order for air cooled by adiabatic cooling, mixing, lifting, or advective cooling to form clouds?The air must be cooled to below its dew point.
29 27What two features are used to classify clouds?Shape and altitude
30 28Name the three basic forms of clouds.Stratus, cumulus, and cirrus
31 29 What are the three altitude groups of clouds and their heights? Low clouds (0 to 2,000m)Middle clouds (2,000 to 6,000m)High clouds (above 6,000m)
32 30Stratus clouds:Clouds with a flat base forming at very low altitudes.
33 31Altostratus clouds:Middle-altitude clouds that usually produce little precipitation.