Download Chapter 7 supplemental notes

Student Name: ____________________
Chapter 7: The atmosphere and space
ST Supplementary Notes
Purpose of this document:
The notes in this document are meant to supplement your textbook. You are responsible for
studying these supplementary notes AND all the ST sections of Chapter 7 in your textbook.
The Earth-Moon System:
Tides are mainly caused by the gravitational attraction of the Earth and Moon to each other,
but also by the gravitational attraction of the Earth and Sun to each other. The gravitational
force between the Earth and Moon is greater than the gravitational force between the Earth
and Sun. The gravitational force is directly proportional to mass and inversely proportional to
distance. Although the sun has more mass than the moon, the distance between the Earth and
Sun is much greater than the distance between the Earth and moon.
Source: http://oceanservice.noaa.gov/education/tutorial_tides/media/supp_tide02.html
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Student Name: ____________________
Chapter 7: The atmosphere and space
ST Supplementary Notes
The Earth-Moon System (continued):
The tidal range is the difference between the water levels at low and high tide. Spring tides
cause the tidal range to be greater than usual (lower low tides and higher high tides). Neap
tides cause the tidal range to be smaller than usual (higher low tides and lower high tides).
Please ALSO refer to the document provided in class named "What causes tides?"
Please ALSO refer to the video: "Watching the Tides"
https://www.youtube.com/watch?v=QcbN9SVkqYU
Source: http://oceanservice.noaa.gov/education/tutorial_tides/media/supp_tide01.html
Tidal Power Plant
Source: http://climatekids.nasa.gov/tidal-energy/
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Student Name: ____________________
Chapter 7: The atmosphere and space
ST Supplementary Notes
Variation of Atmospheric Pressure and Temperature with Altitude (vertical):
http://wps.prenhall.com/wps/media/objects/3083/3157782/blb1801.html
The gravitational force of the Earth pulls the air particles in the atmosphere towards the Earth's
surface. Consequently, the number of air particles in the atmosphere decreases with increasing
altitude (height). This means that the density of the atmosphere also decreases with increasing
altitude. Ninety-nine percent of the air molecules in the atmosphere are situated within 30km
of the Earth's surface.
Atmospheric pressure is the force that air particles exert when they collide with each other and
with other objects. When the density of air increases, the number of collisions between air
particles increases, therefore atmospheric pressure increases as well. Since air density
decreases with increasing altitude, it follows that atmospheric pressure also decreases with
increasing altitude.
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Student Name: ____________________
Chapter 7: The atmosphere and space
ST Supplementary Notes
Changes in Atmospheric Pressure and Temperature with Altitude (height):
Temperature is a measure of the degree of agitation of the particles of a substance. There are
two main factors that are responsible for the variations in temperature within the different
layers of the atmosphere: the density of air and the absorption of solar energy.
1) When the density of air increases, the number of collisions between air particles increases,
so the degree of agitation of the air particles (temperature) increases.
Most of the sun's high energy rays do not reach the troposphere. The temperature in the
troposphere decreases with increasing altitude, because the density of air decreases with
increasing altitude.
2) The greater the solar energy absorbed by air particles, the greater the degree of agitation of
the air particles (temperature).
In the thermosphere, the density of air is very low and it decreases with increasing altitude.
However, the air particles in the thermosphere absorb very high levels of solar energy. In fact,
the higher up within the thermosphere the air particles are, the greater the amount of solar
energy they absorb. Consequently, the temperature of the air particles in the thermosphere is
very high and it increases with increasing altitude.
In the stratosphere, the ozone layer absorbs high energy ultraviolet (UV) rays. In addition, the
ozone molecules higher up within the stratosphere absorb the highest energy UV rays.
Consequently, the temperature of the air particles in the stratosphere increases with altitude.
Changes in Pressure at the Surface of the Earth:
In an area of cold air, whether large (e.g. cold air mass) or small (e.g. high pressure centre),
molecules have less heat energy, so they move less (lower temperature) and closer to each
other. Since cold air has a greater density than warm air, it sinks. Consequently, more air
molecules push down on the surface of the Earth, so the pressure at the surface of the Earth
increases.
In an area of warm air, whether large (e.g. warm air mass) or small (e.g. low pressure centre),
molecules have more heat energy, so they move more (higher temperature) and further apart
from each other. Since warm air has a lower density than cold air, it rises. Consequently, more
air molecules move away from the surface of the Earth, so the pressure at the surface of the
Earth decreases.
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Student Name: ____________________
Chapter 7: The atmosphere and space
ST Supplementary Notes
High pressure centre/
Anticyclone/
Depression
Low pressure centre/
Cyclone
Source: http://www.slideshare.net/rmarchetto/weather-and-climate-2120822
High and low pressure centres at surface without coriolis force:
Surface winds move away from high pressure centres and towards low pressure centres.
High and low pressure centres at surface with coriolis force in Northern hemisphere:
The Coriolis force causes winds in the Northern hemisphere to deviate to the right from their point of
origin. In the Northern hemisphere, wind deviates to the right as it moves away from high pressure
centres. Consequently, in the Northern hemisphere, surface winds circulate clockwise around high
pressure centres, but counter-clockwise around low pressure centres (the opposite occurs in the
Southern hemisphere.
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Student Name: ____________________
Chapter 7: The atmosphere and space
ST Supplementary Notes
Temperature
Volume
(maximum altitude)
Average density
Surface Pressure
Pressure aloft
at same altitude
Warm air mass
Higher (warm)
Cold air mass
Lower (cold)
Greater (Higher)
Low
Low
Smaller (Lower)
High
High
Higher
Lower
Changes in Pressure with Latitude (from equator to poles) Aloft (above):
H aloft
L aloft
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Student Name: ____________________
Chapter 7: The atmosphere and space
ST Supplementary Notes
Changes in Pressure with Latitude (from equator to poles) Aloft (above):
Source: http://www.meted.ucar.edu/dynamics/thermal_wind/print.htm
The air particles near the equator get a higher concentration of radiant energy from the sun, so
they move more (higher temperature) and further apart from each other. Consequently, this
warm air takes up a larger volume and has a lower density.
The air particles near the poles get a lower concentration of radiant energy from the sun, so
they move less (lower temperature) and closer to each other. Consequently, this cold air takes
up a smaller volume and has a higher density.
The top of the troposphere is closer to the surface of the Earth near the poles than near the
Equator, because the warm air near the equator takes up a larger volume than the cold air near
the poles. The warm air at the equator rises, whereas the cold air at the poles sinks.
Consequently, there are more air particles at the surface of the Earth near the poles than near
the equator. The overall number of particles in the atmosphere does not change. This means
that there are more air particles aloft (higher up) near the equator than near the poles. The
pressure aloft is thus higher near the equator than near the poles. Wind aloft moves from the
equator towards the poles, from higher pressure to lower pressure.
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Student Name: ____________________
Chapter 7: The atmosphere and space
ST Supplementary Notes
Winds aloft:
Winds aloft move faster than winds at the surface, because the air particles encounter less
obstacles (e.g. tree and buildings). In addition, to moving from higher to lower pressure, winds
aloft are deflected by the Coriolis force. In the Northern hemisphere, winds are deflected
towards the right from their point of origin. In the Southern hemisphere winds are deflected
towards the left from their point of origin.
Weather associated with high pressure (anti-cyclone) and
low pressure (cyclone/depression) centres at the surface:
Low pressure centres at the surface are usually associated with clouds and precipitation. Low
pressure at the surface is caused by warm air rising. This warm air cools (loses heat) as it rises
(since the temperature decreases with increasing altitude), so it leads to condensation, the
formation of clouds, and precipitation.
High pressure centres at the surface are usually associated with clear and sunny skies. High
pressure at the surface is cause by cold air sinking.
Source: https://sites.google.com/site/badinoweatherquest/stage-2---forecast-weather/stage-2--forecasting
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Student Name: ____________________
Chapter 7: The atmosphere and space
ST Supplementary Notes
Warm and Cold Fronts:
Warm and cold air masses both move towards low pressure centres at the surface, so they
eventually collide.
Warm front
Formation
Horizontal
Movement
Precipitation
Clouds
Warm air mass
displaces cold air mass
Cold front
Cold air mass displaces
warm air mass
Slow
Light rain (quantity),
Over large area,
Long duration
Fast
Heavy rain (quantity),
Over small area,
Short duration
Stratus
Cumulus
Source: http://slideplayer.com/slide/1447163/
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Student Name: ____________________
Chapter 7: The atmosphere and space
ST Supplementary Notes
Source: http://usatoday30.usatoday.com/weather/wlowpres.htm
The Greenhouse Effect and Global Warming:
Please refer to the supplemental diagram and notes completed in class.
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