Download Name

Name:____________________
Date:______________
Adapted from geoteach.com and http://www.weatherdudes.com/facts_display.php?fact_id=35
Lab 19 Drawing Planetary Winds
What Causes Wind?
Wind is caused by the difference in pressure from one point on the earth’s surface to
another. The air moving from the area of higher pressure to the area of lower pressure is
called wind. The air does not move directly from the point of highest pressure to the point of
lowest pressure. The earth’s rotation affects the air flow by deflecting it to the right. This
effect is called the Coriolis Effect. In the Northern Hemisphere, this causes air to flow
clockwise around high pressure areas and counter-clockwise around low pressure
areas.
In General, the difference in pressure across the globe is caused by the uneven heating of
the Earth’s surface from the sun. This is due to several factors. Land warms and cools much
faster than water. (Land has a lower specific heat than water, pg 1 of ESRT’s) and, of course,
latitude affects how much solar radiation is received each day and returned to space each
night.
Purpose: To draw Planetary Wind Belts by carefully following a precise set of directions.
Materials: Ruler, colored pencils, Earth Science Reference Tables (page 14)
Procedure:
1. Remove the last page of this lab, the sheet with the blank map of Earth.
2. On that map connect the tick marks on both the left and right side of the map with a ruler and pencil.
3. In the right margin of your paper label the lines with the following latitude numbers:
0°
30°N
30°S
60°N
60°S
90°N
90°S
4. On the left hand side label the pressure of the lines of latitude using the words “High” and “Low”.
Start by labeling the North Pole “High” and alternate between high and low as you label each line
below it. (eg. High, Low, High, Low, Ect.)
5. Draw 3 arrows in each of the six sections on your map in the direction the air is moving in that
section. These lines should be straight. (Air go from _______ to ________)
6. With a red colored pencil draw new arrows. This time draw arrows that show the Coriolis Effect.
- Northern Hemisphere winds deflect Right
- Southern Hemisphere winds deflect Left
Hint: Look down the arrow towards the point, then deflect the wind in the correct direction.
7. Label each wind belt with the proper name in the middle of the section.
Winds are name according to the direction from which they come:
-
Polar Easterlies (Both Poles)
Northeast tradewinds
Southeast tradewinds
Prevailing (South) Westerlies
Prevailing (North) Westerlies
8. On the right hand side of the map use a green color pencil to indicate (With a small circle) and label
the Subtropical jet stream in both hemispheres.
9. On the right hand side of your map indicate (With a small circle) and label the Polar Front jet stream
in Blue colored pencil.
10. On the left hand side of the map draw a convection current showing the pattern of air flow between
0° and 30°N. Draw a second convection current between 30°S and 60°S.
Planetary Wind Lab Questions.
1. The deflection (bending) of wind, ocean water and objects flying through the air is known as
the _______________________ effect.
2. What causes wind?
3. Explain why cold air is “heavier” and therefore exerts more pressure than warm air.
4. Why is air at 0° and 60 ° north and south latitude wetter, while the air at 30 ° north and south
latitude is drier? (hint: look at what the air is doing at these locations)
Regents Questions.
You will need to use page 4 Surface Ocean Currents and 14 Planetary Wind and Moisture Belts in the
Troposphere, in your Earth Science Reference Tables to answer these questions.
The diagram below represents the planetary wind and moisture belts in Earth's Northern Hemisphere.
Using this diagram, answer questions 1 and 2.
______ 1. The climate at 90° north latitude is dry because the air at that location is usually
A) cool and sinking
B) warm and rising
C) warm and sinking
D) cool and rising
______ 2. The climate at 0 ° latitude is wet because the air at that location is usually
A) cool and sinking
B) warm and rising
C) warm and sinking
D) cool and rising
______ 3. Which map below best represents the global prevailing surface wind patterns
responsible for generating Atlantic Ocean currents?
______ 4.Which map best represents the direction of surface winds associated with the high- and
low-pressure systems?
______ 5.Which graph best shows the average annual amounts of precipitation received at different
latitudes on Earth?
The weather map below shows surface air-pressure readings, in millibars, at various locations in the
United States and Canada. The 1,020-millibar isobars have been drawn and labeled.
Draw the 1,024 and 1,028-millibar isobars on the weather map provided.