Download Name Date Period Part IV: Atmospheric Lifting, Cloud Formation

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Part IV: Atmospheric Lifting, Cloud Formation & Coriolis Effect Study Guide
A. Types of Lifting
a. What causes atmospheric lifting to occur?
Unstable air- Warmer air is close to the ground and rises because it is less dense than
cool air.
b. Orographic Lifting
i. Why does this type of lifting occur?
The mountain forces the warm air up
ii. Describe what happens to the air during this type of lifting.
Warm air rises due to the presence of the mountain. As the air rises, the
temperature decreases cause clouds to form on the windward side of the
mountain. The Air continues over the mountain and sinks without any water
vapor causing a dry climate on the leeward side of the mountain.
iii. What is the difference between the Windward and Leeward side of the
mountain?
Windward- side the wind is coming from, wet and cool
Leeward- opposite side of the mountain, hot and dry
iv. What occurs on the Leeward side of the mountain?
A Rain Shadow
1. Why does this occur?
When air rises on the windward side of the mountain, water vapor in
the air condenses to form and cloud therefore, there is no water vapor
in the air when it reaches the leeward side of the mountain creating a
dry climate.
c. Convective Lifting
i. Why does this type of lifting occur?
This occurs when the surface becomes warm from the sun’s radiation, warming
up the surrounding air.
ii. Where does this occur on Earth?
The Equator
d. Convergent Lifting
i. Why does this type of lifting occur?
Low Pressure
e. Frontal Lifting
i. Why does this type of lifting occur?
When warm and cool air masses meet
ii. Why does the cold air sink and the warm air rise?
Cold air is denser than warm air causing it to sink and warm air to rise
B. Humidity & Saturation
a. Define Humidity:
The amount of water vapor in the air
b. What is relative humidity?
Amount of humidity in the air expressed as a ratio or percentage
c. What will occur when relative humidity has reached 100%?
Clouds will form
d. Define saturation:
The maximum amount of water vapor the air can hold at a given temperature
e. How does water vapor saturation change with temperature?
Warmer air can hold more water vapor than cold air
C. LCL & Dew Point
a. What does LCL stand for?
Lifting Condensation Level
b. Define LCL:
The height/ altitude when water vapor condenses to form a cloud
c. What is Dew Point?
The temperature at which water vapor condenses
i. How does dew point affect cloud formation?
As air rises, temperature decreases. When the air has reached the Dew Point,
the water vapor in the air will condense to form clouds
d. What will happen to water vapor temperature as it increases in altitude in the
troposphere?
It will get colder or decrease
e. Why do clouds appear to be flat at the bottom in the sky?
The flat bottom is the where the water vapor has reached the dew point and the
condensation level. Below that point, the water in the air is still water vapor (gas).
D. Cloud Formation
a. What is a cloud?
Water droplet suspended in the air
b. Starting with the Sun’s radiation, describe how clouds form in the Troposphere.
The Sun’s radiation heats Earth’s surface. Through conduction, the surrounding air is
then heated. When air gets warm, it begins to rise. As air rises in altitude in the
Troposphere, temperature and pressure decrease (go down) causing the air to cool and
expand. Once the air has reached the dew point, the water vapor will condense into
water droplets and form at the condensation level. As long as there is enough water
vapor rising, the cloud will continue to build until the water droplets become too large
and fall as precipitation (rain, sleet, hail, snow).
c. Define Condensation nuclei:
Microscopic particles suspended (floating) in the air where water vapor condenses
around (sticks to) to form a cloud. (Remember the smoke in our Cloud in the Bottle lab)
E. Formation of a Thunderstorm
a. Name and describe the 3 stages of a thunderstorm
i. Stage 1: Cumulus Stage
Warm air rises causing water vapor to condense at the Dew Point & Condensation
level forming a Cumulus Cloud.
ii. Stage 2: Mature Stage
Warm moist air continues to rise with, creating a large Cumulonimbus Cloud.
This is the Thunderstorm. Updrafts and downdrafts are occurring at the same
time. The downdrafts bring down precipitation and strong winds.
iii. Stage 3: Dissipating Stage
Updrafts stop and downdrafts take over cloud. If there is no rising air, clouds do
not form. Cumulonimbus cloud turns back into a cumulus cloud.
F. Coriolis Effect
a. What is the Coriolis Effect?
The curving of wind due to Earth’s rotation. The Earth spins at different speed based on
latitude. This causes air to be “deflected” and not move in a straight line.
b. How does the Coriolis Effect affect winds and weather systems?
Global Winds curve rather then move in a straight line. Earth’s rotation causes
Hurricanes to spin in different direction depending on if it is located in the Northern
Hemisphere or Southern Hemisphere.
G. Review previous topics
a. What is the order of the layers of the atmosphere?
Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere
b. How does temperature change with altitude in the Troposphere?
Temperature decrease with altitude (gets colder)
c. Wind moves from HIGH pressure to LOW pressure.
d. Warm air RISES, cold air SINKS.
e. What are the 3 types of heat transfer?
Radiation, Conduction, Convection
i. Explain how each type of heat transfer heats and changes the atmosphere.
Radiation- (moves in waves) comes from the sun and heats Earth’s surface
Conduction- (moves through touch) air close to the surface is heated because it
is touching the surface
Convection- (move due to difference in temperature) warm air rises, cold air
sinks