Name: _______________________________________
Period:__________
Meteorology Unit
1
Vocabulary Terms
Weather –
Ozone –
Convection Currents –
Insolation –
Greenhouse effect –
Adiabatic –
Transpiration –
Dew Point Temperature –
Psychrometer –
Absolute humidity –
Relative humidity –
Clouds –
Precipitation –
Wind –
Pressure gradient –
Sea breeze –
2
Land breeze –
Coriolis effect –
Air mass –
Front –
Cyclone –
Anticyclone –
The Fujita Scale –
Hurricane –
Storm Surge –
Isobars –
Isotherms –
Climate –
El Nińo –
La Nińa –
Windward –
Leeward –
3
Directions: Read the following passages on below and then answer the questions that follow.
What is Weather?
We probably talk about weather more often than anything else. How often have you started talking to
people by saying, “Wow, look at that rain!” or "It is cold out today!”
Weather affects us in many ways. We dress according to the weather. We make plans hoping for certain
weather conditions. Sunny weather can make you feel happy. Rainy weather can make you feel sad.
Weather affects what kind of food you eat. It even affects how much your family pays for food.
Weather is an important aspect to life. But, what exactly is weather?
Weather is the present condition of the atmosphere at a particular location. It is different from place to
place. Weather is always changing from moment to moment.
Several conditions make up weather. A few major criteria are:
 air temperature
 air pressure
 precipitation (rain, snow, hail, sleet, drizzle)
 appearance of the sky (clear or cloudy)
 wind speed
 wind direction
 humidity (water in the air)
_______________________________________________________________________________________________________________________________________
The Atmosphere: What Is It?
Now that we know that weather is the condition of the atmosphere at a particular location, let's find out
more about the four layers that make up the atmosphere.
The layer of the atmosphere that is closest to the Earth is called the troposphere. This part of the
atmosphere is where we live and what we breathe. This is also the part of the atmosphere where most of the
Earth's weather occurs. Temperature in this part of the atmosphere decreases about 3.5 ºF for every 1,000 feet
that you go up. (That's 6.5 ºC for every 1,000 meters.) Finally, at a height of 6 to 10 miles above the Earth, or 10
to 16 kilometers, the temperature does not drop anymore. This area is known as the tropopause.
The second layer of the atmosphere is known as the stratosphere. This layer begins about 6 to 10 miles
above the Earth's surface and ends about 30 miles, or 48 kilometers, away from the Earth. There isn't very much
moisture in this layer, so there are usually not very many clouds. This is where airline pilots like to fly their jets
so their passengers are not bounced around by the weather. In the stratosphere, temperatures increase with
altitude until the top of the stratosphere is reached. This is called the stratopause. This upper part of the
stratosphere has most of the atmosphere's ozone, which traps ultraviolet rays from the sun.
The third layer of the atmosphere is called the mesosphere. This layer goes to a height of about 50 miles
above the Earth's surface. Like in the troposphere, temperature drops with increases in altitude in the
mesosphere. There are very strong winds that blow in this section of the atmosphere. Over most of the United
States they blow from west to east during the winter months and from east to west during the summer months.
Trails of the hot gases left by burning meteors may be seen in this layer of the atmosphere. The top part of the
mesosphere is called—you got it right—the mesopause.
The final layer is called the thermosphere. This layer is very thin and during the day is exposed to
radiation from the sun. It is very hot, with temperatures reaching as high as 1,100 ºF or 600 ºC. The
thermosphere may be divided into two parts: the ionosphere and the exosphere. The ionosphere is very
important for radio communications because it is able to reflect radio waves back to Earth and stop them from
continuing into space. This is also the part of the atmosphere that creates auroral displays (sometimes known as
the Northern Lights). The exosphere has almost no air. Satellites and other spacecraft can travel in this part of
the atmosphere with very little resistance. The molecules in this part of the atmosphere move very quickly.
Sometimes they are moving so fast they are able to get away from the Earth's gravity. We are slowly losing
these parts of our atmosphere. But—don't fret too much---it should take billions of years before all of the air
around the Earth disappears.
4
Reading questions
1.) What are the four layers of the atmosphere, beginning with the layer closest to Earth's surface?
2.) Where does most of Earth's weather occur?
3.) Why do airline pilots like to fly in the stratosphere?
4.) If you see a falling star, in which part of the atmosphere do you think the meteor is traveling?
5.) Why is the ionosphere important for communications?
Structure of the Atmosphere: A Diagram
Directions: The graph below shows altitudes and temperatures for the four main layers of the atmosphere.
Label the four layers and then complete the statements that follow.
1. _____________________________________________
2. _____________________________________________
3. _____________________________________________
4. _____________________________________________
5. The coldest temperatures in the atmosphere occur at an altitude of about ______________________.
6. The hottest temperatures in the atmosphere occur in the _________________________.
7. Temperatures increase in the ______________ and _________________ layers of the atmosphere.
8. As you move up through the mesosphere, the temperature ____________________.
5
Insolation and Reflection of Solar Energy
Directions: Circle the answer that best completes each question below.
1. The diagram to the right
shows the altitude and apparent
position of the noontime Sun,
as seen from various latitudes
on Earth on a particular day of
the year. Letters A through D
represent locations on Earth's
surface.
What is the altitude of the
noontime Sun at the Equator
on this date?
(1) 23½°
(2) 43°
(3) 66½°
(4) 90°
1.
2.
3.
4.
2. On which date does the maximum
duration of insolation occur in the Northern
Hemisphere?
(1) March 21
(2) June 21
(3) September 23
(4) December 21
3. What is the primary reason the United States is warmer in July
than in February?
(1) The Earth is traveling faster in its orbit in February.
(2) The altitude of the noon Sun is greater in February.
(3) The insolation in the United States is greater in July.
(4) The Earth is closer to the Sun in July.
4. At which latitude would the duration of
insolation be greatest on December 21?
23½° South
0°
10° North
23½° North
5. The diagram to the right
represents a single light source
directly over surface ab when in
position 1. As the light is moved
from position 1 to position 2, which
is of equal distance form the
surface, what will happen to the
light intensity on the surface ab?
(1) decrease
(2) increase
(3) remain the same
(4) increase, then decrease
6
Use the diagrams below to answer questions 6 - 11. These diagrams show the general effect of the Earth's
atmosphere on insolation from the Sun at middle latitudes during both clear-sky and cloudy-sky conditions.
The graph shows the percentage of insolation reflected by the Earth's surface at different latitudes in the
Northern Hemisphere in winter.
6. Approximately what percentage of the insolation
actually reaches the ground at 45° North latitude on a
clear day?
(1) 45%
(2) 60%
(3) 80%
(4) 100%
9. Which factor keeps the greatest percentage of
insolation from reaching the Earth's surface on cloudy
days?
(1) absorption by cloud droplets
(2) reflection by cloud droplets
(3) absorption by clear-air gas molecules
(4) reflection by clear-air gas molecules
7. According to the graph, on a winter day at 70° N
10. Which statement best explains why, at high
latitude, what approximate percentage of the insolation latitudes, reflectivity of insolation is greater in winter
is reflected by the Earth's surface?
than in summer?
(1) 50%
(1) The North Pole is tilted toward the Sun in winter.
(2) 65%
(2) Snow and ice reflect almost all insolation.
(3) 85%
(3) The colder air holds much more moisture.
(4) 100%
(4) Dust settles quickly in cold air.
8. The radiation that passes through the atmosphere
and reaches the Earth's surface has the greatest
intensity in the form of
(1) visible-light radiation
(2) infrared radiation
(3) ultraviolet radiation
(4) radio-wave radiation
11. Buffalo, NY is located ≈ 43ºN. According to the
graph, on a winter day at this location, what
approximate percentage of the insolation is reflected
by the Earth's surface?
(1) 40%
(2) 65%
(3) 85%
(4) 100%
7
Adiabatic Lapse Rates
Directions: Circle the answer that best completes each question below.
Use the diagrams below to answer questions 1 – 3. Diagram A represents the flow of air over a
mountain. Diagram B shows the temperature of the ascending and descending air at various levels.
1. What is the approximate temperature of the
descending air at an elevation of 1,600 meters?
(1) +15°C
(2) +2°C
(3) 5°C
(4) 12°C
2. What is the total increase in the temperature of the
air as it descends from the top to the base of the
mountain?
(1) 15°C
(2) 22°C
(3) 3°C
(4) 27°C
3. The air warms as it descends on the leeward side of the mountain because
(1) air is compressed as it descends
(2) air expands as it descends
(3) air is heated by the Sun at the top of the mountain
(4) more precipitation occurs on the leeward side of the mountain than on the windward side
The diagram below shows wind flowing over
a mountain range.
4. As the wind flows down the leeward side of the mountain
range, the air becomes
(1) cooler and drier
(2) cooler and wetter
(3) warmer and drier
(4) warmer and wetter
8
Air Pressure
Directions: After reading the short excerpt on Air Pressure below, follow the instructions below.
Air consists of atoms and molecules that have mass. Therefore, air has mass. Because air has mass, it
also has other properties, including density and pressure. The amount of mass per unit volume of a
substance is called the density of the substance. The force per unit area is called pressure. Air pressure is the
result of the weight of a column of air pushing down on an area. The molecules in air push in all directions.
This is why air pressure doesn’t crush objects.
Falling air pressure usually indicates that a storm is approaching. Rising air pressure usually means that
the weather is clearing. A barometer is an instrument that measures changes in air pressure. There are two
kinds of barometers: mercury barometers and aneroid barometers. A mercury barometer consists of a
glass tube open at the bottom end and partially filled with mercury. The open end of the tube rests in a dish of
mercury, and the space above the mercury in the tube contains no air. The air pressure pushing down on the
surface of the mercury in the dish is equal to the weight of the column of mercury in the tube. At sea level, the
mercury column is about 76 centimeters high, on average. An aneroid barometer has an airtight metal
chamber that is sensitive to changes in air pressure. The thin walls of the chamber flex in and out as air pressure
changes, and the movements are recorded on a dial.
In weather reports, air pressure usually is given in inches of mercury. National Weather Service maps
indicate air pressure in millibars (mb). One inch of mercury equals 33.87 mb.
Altitude, or elevation, is the distance above sea level. Air pressure decreases as altitude increases. As
air pressure decreases, so does density. Sea-level air has the weight of the whole atmosphere pressing on it, so
air pressure is highest at sea level. Air pressure is much lower at the tops of mountains. There the low density of
air can make it hard to breathe because there is less oxygen in each cubic meter of air.
Directions: Study the figure to the right and then complete the following
statements.
1. Altitude is greater at point _____.
2. Air pressure is greater at point _____.
3. Density of the air is greater at point ______.
4. A cubic meter of air has less mass at point______.
5. The percentage of oxygen in the air at point A is ≈________%.
Directions: Answer the following questions in the space provided below.
6. State three properties of air.
7. Why doesn’t air pressure crush objects such as your desk?
8. What two units of air pressure are used in weather reports?
9
Temperature Scale Conversions
After reading the short excerpt on Temperature and Thermometers below, follow the instructions below.
Temperature and Thermometers
Temperature is the average amount of energy of motion in the molecules of a substance. It is a measure
of how hot or cold a substance is. Temperature is one of the most important elements of weather.
Air temperature is usually measured with a thermometer. A thermometer is a thin glass tube with a
bulb on one end that contains a liquid, usually mercury or colored alcohol. Thermometers work because liquids
expand when they are heated and contract when they are cooled. When the air temperature increases, the liquid
in the bulb expands and rises up the column. When the air temperature decreases, the liquid contracts and falls
back down the column.
The three standard scales for measuring temperature are Fahrenheit, Celsius, and Kelvin. Daniel Gabriel
Fahrenheit invented his initial temperature scale in the early 1700’s. Anders Celsius created a temperature scale
(which was actually reversed from its known version today) in 1742. In 1848, Lord William Thomson Kelvin
wrote a paper that called for need for an “infinite cold” (absolute zero), and thus this scale was named after him.
Directions: Using the temperature conversion chart from your ESRT’s (below), complete the data table below.
ºF
ºC
K
212
0
-40
310
293
10
140
Note: There isn’t a degrees symbol (º) used for
Kelvin temperatures.
10
Water in the Atmosphere
Directions: After reading the short excerpt below, follow the instructions below.
Recall that water is constantly moving between Earth and the atmosphere in the water cycle. Water vapor enters the
air by evaporation from the oceans and other bodies of water. Evaporation is the process by which water molecules
in liquid water escape into the air as water vapor. Some of the water vapor in the atmosphere condenses to form
clouds. Then rain and other forms of precipitation fall from the clouds toward Earth’s surface.
Humidity is a measure of the amount of water vapor in the air. The percentage of water vapor in the air
compared to the maximum amount the air could hold is called the relative humidity. Evaporation of moisture from
your skin removes heat and helps to keep your body’s temperature comfortable. If the relative humidity is high,
moisture on your skin evaporates slowly and cools your body less.
Relative humidity can be measured with a
psychrometer. A Psychrometer (see diagram to the
right) has two thermometers, a wet-bulb thermometer
and a dry bulb thermometer. Air is blown over both
thermometers. Because the wet-bulb thermometer is
cooled by evaporation, its reading drops below that
of the dry-bulb thermometer. The relative humidity
can be found by comparing the temperatures of the
wet-bulb and dry-bulb thermometers.
Clouds of all kinds form when water vapor in the air becomes liquid water or ice crystals. The process
by which molecules of water vapor in the air become liquid water is called condensation. As air cools, the amount
of water vapor it can hold decreases. When the air becomes saturated, some of the water vapor in the air condenses
to form droplets of liquid water. The temperature at which condensation begins is called the dew point. If the dew
point is below the freezing point, the water vapor may change directly into ice crystals. For water vapor to condense,
tiny particles must be present so the water has a surface on which to condense. Water that condenses from the air
onto a cold surface, such as blades of grass, is called dew. Frost is ice that has been deposited directly from the air
onto a cold surface. Water vapor condenses to form clouds when warm air rises.
Meteorologists classify clouds
according to their altitude of
development and shape. The 4 families
of height development are: Low, middle,
high, and vertical development. Of the
clouds shapes, the three basic are cumulus,
stratus, and cirrus.
Clouds that look like fluffy,
rounded piles of cotton are called cumulus
clouds. Cumulus clouds usually indicate
fair weather. Towering cumulus clouds
with flat tops, called cumulonimbus clouds,
often produce thunderstorms. Clouds that
form in flat layers are called stratus
clouds. Stratus clouds that produce rain or
snow are called nimbostratus clouds.
http://eo.ucar.edu/webweather/cloud3.htm
Wispy, feathery clouds are called cirrus clouds. Cirrus clouds are very high, and they are made mostly of ice
crystals. Clouds that form at or near the ground are called fog. Fog often forms when the ground cools at night after a
warm, humid day. All told, there are 10 basic cloud types.
11
Dew Point and Relative Humidity
Directions: Use your ESRT’s to complete the chart below. (Data from C. Burrows)
12
Winds
Directions: Use your ESRT’s to identify the global wind belts and calm areas in the figure below..
1. ____________________________
2. ____________________________
3. ____________________________
4. ____________________________
5. ____________________________
Air Masses
Directions: After reading the short excerpt on Air Masses, answer the questions that follow.
A huge body of air that has similar temperature, humidity, and air pressure throughout it is called an air
mass. Scientists classify air masses according to temperature and humidity. Tropical (T), or warm, air masses
form in the tropics and have low air pressure. Polar (P), or cold, air masses form north of 50° north latitude
and south of 50° south latitude and have high air pressure. Maritime (m) air masses form over oceans and are
humid. Continental (c) air masses form over land, in the middle of continents, and are dry.
Although there are other types, there are four major types of air masses influence the weather in
North America: maritime tropical (mT), continental tropical (cT), maritime polar (mP), and continental
polar (cP). mT air masses from the Gulf of Mexico bring warm, humid air to the eastern United States. mT air
masses from the Pacific Ocean bring warm, humid air to the West Coast. cT air masses from the Southwest
bring hot, dry air to the southern Great Plains. mP air masses from the Pacific Ocean bring cool, humid air to
the West Coast. mP air masses from the Atlantic Ocean are often pushed out to sea by westerly winds. cP air
masses from central and northern Canada bring cold air to the central and eastern United States.
This map shows the
air masses that bring
typical weather to
North America.
13
1. Name the four kinds of air masses this map shows.
2. Which of these air masses move in from:
a. the north? _________________________
3. Which air mass brings
a. cold and DRY air? __________________
b. the south? _________________________
b. warm and DRY air? _________________
c. the land? __________________________
c. cold and MOIST air? ________________
d. the ocean? _________________________
d. warm and MOIST air? _______________
Fronts
Directions: After reading the short excerpt on Air Masses, answer the questions that follow.
The prevailing westerlies generally push air masses from west to east in the United States. As air masses
move across the land and the oceans, they bump into each other. However, if they have different temperatures
and densities, they do not mix. The area where the air masses meet and do not mix becomes a front. When air
masses meet at a front, the collision often causes storms and changeable weather.
There are four major types of fronts: cold fronts, warm fronts, stationary fronts, and occluded
fronts. A cold front forms when cold air moves underneath warm air, forcing the warm air to rise. Cold fronts
move quickly and bring cold, dry air. A warm front forms when warm air moves over cold air. Warm fronts
move slowly and bring warm, humid air. A stationary front forms when cold and warm air masses meet but
neither one has enough force to move the other. It may bring many days of clouds and precipitation. An
occluded front forms when a warm air mass is caught between two cooler air masses. The warm air mass is cut
off, or occluded, from the ground. The occluded warm front may cause clouds and precipitation.
Base your answer on the weather map to the
right, which shows air temperature and winds
for a few locations in the eastern half of the
United States. A large low-pressure system is
shown on the map.
1.) Which type of front extends eastward from
the low-pressure center?
1.
2.
3.
4.
cold
warm
occluded
stationary
2.) If the cold front advances faster than the
warm front, what kind of front is the most likely
result?
1. a longer warm front
2. a longer cold front
3. an occluded front
4. a stationary front
14
The map shows weather
systems over the central and
eastern United States and
weather data for several
cities.
3.) DRAW the general flow
of wind around the low.
4.) Most weather systems
like this one move across the
United States toward the
1.
2.
3.
4.
southwest
southeast
northwest
northeast
5.) In the next few hours the
temperature in Atlanta, GA
will probably
1. increase
2. decrease
3. remain the same
4. increase then
decrease
6.) Which cross-sectional
diagram (to the right) of the
lower atmosphere along line
AB best represents the fronts
and the movement of air
masses?
15
Cyclones and Anticyclones
Directions: Circle the answer that best completes each question below.
1.) Which map to the right best represents the normal
air circulation around a high-pressure air mass located
over central New York State?
2.) Which map view best shows the movement of
surface air around a low-pressure system in the
Northern Hemisphere?
3.) Surface winds within a low-pressure system (in the Northern hemisphere) generally flow
1.
2.
3.
4.
clockwise and toward the center of the system
clockwise and away from the center of the system
counterclockwise and toward the center of the system
counterclockwise and away from the center of the system
16
Severe Weather – Thunderstorms and Tornadoes
Directions: After read the following sentence, answer the question that follows:
An Earth science class is preparing a booklet on emergency preparedness.
1.) State one safety measure that should be taken to minimize danger from the threat of a thunderstorm.
2.) State one safety measure that should be taken to minimize danger from the threat of a tornado.
Base your answer to questions 3 - 4 on the cross section below, which shows a typical cold front moving over
New York State in early summer.
3.) Explain why the warm, moist air is rising at the frontal boundary.
4.) Central Canada was the geographic source region for the cP air mass shown in the cross section. Identify the
most likely geographic source region for the mT air mass shown in the cross section.
Base your answer to questions 5 - 6 on the data table and map on the next page and on your knowledge of Earth
science. The data table shows the altitude of the top of a thunderstorm cloud and the probability of hail being
formed for a location in New York State. The map shows the average number of days per year hail strikes the
ground in different regions of the United States.
17
5.) Describe the relationship between the altitude of the top of a thunderstorm cloud and the probability that hail
will be produced by that cloud.
6.) Name a city or town in New York State that has an average number of 2 days per year where hail strikes the
ground according to the map above.
Base your answer to questions 7 - 9 on the passage, map and data table on the next page and on your knowledge
of Earth science. The passage describes a tornado produced from a thunderstorm that moved through a portion
of New York State on May 31, 1998.
New York Tornado
A small tornado formed and moved through the town of Apalachin, New York, at 5:30 p.m., producing
winds between 40 and 72 miles per hour. The tops of trees were snapped off, and many large limbs fell to the
ground. The path of the destruction measured up to 200 feet wide. At 5:45 p.m., the tornado next moved
through the town of Vestal where winds ranged between 73 and 112 miles per hour. Many people experienced
personal property damage as many homes were hit with flying material.
At 6:10 p.m., the tornado moved close to Binghamton, producing winds between 113 and 157 miles per
hour. A 1000-foot television tower was pushed over, and many heavy objects were tossed about by the strong
winds. Then the tornado lifted off the ground for short periods of time and bounced along toward the town of
Windsor. At 6:15 p.m., light damage was done to trees as limbs fell and small shallow-rooted trees were pushed
over in Windsor.
The tornado increased in strength again at 6:20 p.m. as it moved into Sanford. Some homes were
damaged as their roof shingles and siding were ripped off. One mobile home was turned over on its side. The
tornado moved through the town of Deposit at 6:30 p.m., creating a path of destruction 200 yards wide. The
tornado skipped along hilltops, touching down occasionally on the valley floors. However, much damage was
done to homes as the tornado’s winds reached their maximum speeds of 158 to 206 miles per hour. The tornado
weakened and sporadically touched down after leaving Deposit. By 7:00 p.m., the tornado had finally ended its
1 -hour rampage.
18
Map of Lower Central New York State
The Fujita Scale
F-Scale Wind Speed
Number
(mph)
Type of Damage Done
F0
40-72
Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages
sign boards.
F1
73-112
The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes
pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be
destroyed.
F2
113-157
Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over;
large trees snapped or uprooted; light object missiles generated.
F3
158-206
Roof and some walls torn off well constructed houses; trains overturned; most trees in forest
uprooted
F4
207-260
Well-constructed houses leveled; structures with weak foundations blown off some distance; cars
thrown and large missiles generated.
F5
261-318
Strong frame houses lifted off foundations and carried considerable distances to disintegrate;
automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel reinforced
concrete structures badly damaged.
7.) The tornado mentioned in this passage traveled from Apalachin to Vestal, then to Binghamton, on to
Windsor, next to Sanford, and finally to Deposit. List the approximate Fujita Intensity scale values for each city
the tornado hit in the spaces provided:
Apalachin _____ Vestal _____
Binghamton _____ Windsor _____ Sanford _____ Deposit _____
8.) Using the map above and the cities and towns listed in question #7, DRAW a line showing the approximate
path of the tornado from 5:30pm to 6:30p.m on May 31, 1998.
9.) Using the path you drew for question number 8 above, state the approximate length (to the nearest whole
mile) of the tornado path from 5:30pm to 6:30p.m on May 31, 1998: ________ miles
19
Severe Weather – Hurricanes
Base your answer to questions 1 + 2 on the map below and on your knowledge of Earth science.
The map shows areas of hurricane formation and normal hurricane paths in the Atlantic Ocean during
May, July, and September. The areas of hurricane formation usually have surface ocean-water temperatures
greater than 80°F.
1.) How does the area of hurricane formation change from May to
September?
2.) State one reason why most hurricane paths curve northeastward as hurricanes move north of 30° N latitude.
--------------------------------------------------------------------------------------------------------------------------------------Directions: Fill in each blank in the diagram with one of the following phrases:
Path of hurricane; eye of hurricane; warm, moist air; and wind direction.
20
Directions: Answer the following questions in the space provided.
5. Why should you be on the lookout for tornadoes during a severe thunderstorm?
6. Why should you avoid touching metal objects during a thunderstorm?
7. Where is the safest place to be during a tornado?
8. Why does a hurricane lose strength once it passes over land?
9. What should you do if you are caught in a snowstorm?
Directions: Fill in the blank with the correct letter of the statement that best fits each term.
_____ 10. storm
a. a tropical storm that has winds of 119 kilometers per hour or higher
_____ 11. lightning
b. a sudden spark, or energy discharge, between parts of a cloud or between the cloud
and the ground
_____ 12. tornado
c. a violent disturbance in the atmosphere
_____ 13. hurricane
d. a rapidly whirling, funnel-shaped cloud that reaches down from a storm cloud to
touch Earth’s surface
_____ 14. storm surge
e. move away temporarily
_____ 15. evacuate
f. a “dome” of water that sweeps across the coast where a hurricane lands
21
Weather Station Models
Directions: Using the station models below, decode the weather conditions and record the information
displayed in the following table:
22
Directions: In the chart below, you’ll find meteorological data that was taken at several different New York
State airports. Use this data to create station models for each city listed in the table.
23
Weather Maps/ Isobars and Isotherms
Directions: The map below shows wind direction and air pressure for several different weather stations.
Connect the areas of equal air pressure on the map to form isobars. Label each isobar with the correct air
pressure. You should have an isobar for each of the following pressures: 996, 1000, 1004, 1008, 1012, and 1016
millibars. Interpolate between numbers where necessary. Work from the lowest to the highest pressure. Also
label the low-pressure center “L” and the high-pressure center “H.” Then answer the following questions.
1. Describe/ show the direction of wind movement around the center of high air pressure.
2. Describe/ show the direction of wind movement around the center of low air pressure.
3. Describe/ show the direction that winds appear to blow between centers of high and low pressure.
24
Ocean Currents
Directions: After reading the short excerpt on Ocean Currents, answer the questions that follow.
Currents are large streams of moving water that flow through the oceans. Unlike waves, currents carry water
great distances. Some currents move water at the surface of the ocean. Other currents move water deep below
the surface.
Surface currents, which affect water to a depth of several hundred meters, are driven mainly by
winds. Therefore, surface currents follow the major wind patterns of the globe, moving in a circular pattern in
the five major ocean basins. The Coriolis effect, which is the effect of Earth’s rotation on the direction of winds
and currents, is the reason for this circular pattern. The Coriolis effect causes currents to curve to the right in the
Northern Hemisphere and to the left in the Southern Hemisphere. The largest, most powerful surface current in
the North Atlantic Ocean is the Gulf Stream.
Climate is the pattern of temperature and precipitation typical of an area over a long period of time.
Currents affect climate by moving cold and warm water around the globe. A surface current warms or cools
the air above it, influencing the climate of the land near the coast.
Deep currents are caused by differences in density rather than surface winds. Density, in turn,
depends on temperature and salinity. When ice forms near the poles, the salinity of the remaining liquid water
increases. This cold, salty water is dense and sinks, flowing along the ocean floor as a deep current. Deep
currents carry cold water from the poles back toward the equator. They flow much more slowly than surface
currents.
Another type of water movement is upwelling. This is the upward movement of cold water from the
ocean depths to replace warm surface water moved away by winds. Upwelling brings up tiny ocean organisms,
minerals, and other nutrients from the deeper layers of the water. Areas of upwelling usually attract huge
schools of fish that feed on these nutrients.
Complete the following table.
SECTION
ANDR
5. How do surface currents affect climate?
6. Why does upwelling attract huge numbers of fish?
Fill in the blank to complete each statement.
7. ___________________ are large streams of moving water that flow through the oceans.
8. The effect of Earth’s rotation on the direction of winds and currents is called the ________________.
9. ______________ is the pattern of temperature and precipitation typical of an area over a long period of time.
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10. The Canaries Current along the west coast of
11. In the Northern Hemisphere, planetary winds
Africa and the Peru Current along the west coast of
blowing from north to south are deflected, or curved,
South America are both
toward the west. This deflection is caused by the
1. warm currents that flow away from the Equator
1. unequal heating of land and water surfaces
2. warm currents that flow toward the Equator
2. movement of low-pressure weather systems
3. cool currents that flow away from the Equator
3. orbiting of Earth around the Sun
4. cool currents that flow toward the Equator
4. spinning of Earth on its axis
El Niño—A Warm Ocean Current
Directions: After reading the short excerpt on Ocean Currents, answer the questions that follow.
From the fall of 1997 through the spring of 1998, the
weather across the United States, and the rest of the
world, was highly unusual. Tornadoes devastated parts of
Florida. The upper Midwest enjoyed a mild winter. The
West Coast braced for floods and mudslides. Australia
and Indonesia faced droughts and brush fires. All of
these unusual weather patterns could be traced to one
event—El Niño.
El Niño is a warm current in the Pacific Ocean off the
coast of South America. El Niño is a Spanish term that
means the Christ child. Peruvian sailors gave this name
to the current because it usually appears during the
Christmas season. An El Niño occurs when the easterly
trade winds over the central and western Pacific Ocean
weaken. Normally, these trade winds blow off the coast
of South America to the west. These winds push the
warm ocean water at the surface toward the western part
of the Pacific Ocean near Australia and Indonesia. As the
warm water evaporates, clouds form that bring rain to
Indonesia and Australia. The water that is blown
westward is replaced by an upwelling of cold water
along the coast of South America. This cold water is full
of food and nutrients for fish and other marine animals.
During an El Niño, the easterly trade winds blowing off the coast of South America weaken, and the warm
water flows back toward the east. The upwelling of cold water along the coast of South America stops. Since
the warm water is moving eastward, the clouds form much farther east. These clouds bring rain to the coasts of
North and South America, leaving Australia and Indonesia with droughts. An El Niño occurs every two to
seven years and is sometimes followed by a La Niña, a cold ocean current. El Niño is not just a recent event.
Historical records show occurrences of El Niño’s as early as 1567.
1. What causes an El Niño to occur?
2. Identify the climate factors that change during an El Niño.
3. How would an El Niño affect the fishing industry in South America?
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4. Why do countries in the western Pacific, such as Australia and Indonesia, experience droughts during an El
Niño?
5. Does El Niño cause a permanent change in the climate? Explain.
Windward and Leeward Winds
Directions: Answer the questions that follow.
The cross section below shows the prevailing winds
that cause different climates on the windward and
leeward sides of this mountain range.
1.) Compared to the climate conditions on the leeward
side of this mountain range, the conditions on the
windward side are usually
1.
2.
3.
4.
cooler and wetter
cooler and drier
warmer and wetter
warmer and drier
2.) The diagram shows warm, moist air moving off the ocean and over a mountain, causing precipitation
between points 1 and 2.
Describe two changes that occur to the warm, moist air between points 1 and 2 that would cause cloud
formation.
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