Atmosphere Stuff

Name ______Period ______

Atmosphere Stuff

Read each topic and hi-lite/annotate

Answer practice questions to review your understanding

Watch videos and draw diagrams when required

WEATHER AND CLIMATE
We refer to the local, short-term conditions in an area as weather. This includes temperature, humidity, cloud cover, precipitation, wind speed, and atmospheric pressure. But weather only happens on time scales from seconds to days. The average weather in an area over a long period of time (at least several decades) is called climate.
Climate is defined by temperature and precipitation and is what determines plants in an area, which in turn, determines animals.
There are six different factors that affect the distribution of heat and precipitation around the world, thus leading to varying climates. These six factors are unequal heating of Earth by the Sun, atmospheric convection currents, the rotation of Earth, Earth’s orbit around the sun on a tilted axis, ocean currents, and Earth’s topography.
We will start with general information about the atmosphere, then explore these six climate-determining factors. / Practice
Which of the following is the best description of a region’s climate?
A.  The amount of rainfall that an area receives over a period of 1 year.
B.  The average precipitation over a 1-2 year time period.
C.  The average high temperature of a region.
D.  The average temperature and precipitation over several decades.
E.  The average temperature and rainfall over a period of 1-2 years.
Answer: ______
Take a deep breath. About 99% of the volume of air you inhaled consists of two gases: nitrogen (78%) and oxygen (21%). The remainder consists of water vapor (varying from 0.01% at the frigid poles to 4% in the humid tropics, for an average of about 1%), 0.93% argon (Ar), 0.039% carbon dioxide (CO2) and trace amounts of dust and soot particles as well as other gases including methane (CH4), ozone (O3), and nitrous oxide (N2O). / Review Question:
The atmosphere is 78% nitrogen but it is in a form we are unable to utilize. Describe how we are able to convert nitrogen gas (N2) into a more useable form (use appropriate vocab, feel free to draw diagram)
EARTH’S ATMOSPHERE
The density of the gas molecules per unit of air volume varies throughout the atmosphere because gravity pulls its gas molecules toward the earth’s surface. About 75-80% of the earth’s air mass is found in the atmospheric layer closest to earth’s surface – the troposphere. This layer extends about 11 miles above sea level at the equator and 4 miles above sea level over the poles. Most of the weather we experience occurs in this layer. Air currents, winds, and concentrations of CO2 and other greenhouse gases in the troposphere play a major role in the planet’s weather and climate.
The layers of the atmosphere are based on differences in temperature as altitude increases. Because of radiation from Earth and the objects on it, the troposphere is warmer at sea level (0 km altitude) and cools as altitude increases.
Moving away from Earth, the next layer of the atmosphere is the stratosphere. The stratosphere contains a layer of air with a high concentration of ozone molecules (O3), called the ozone layer. Stratospheric ozone is formed when oxygen molecules (O2) in this layer interact with ultraviolet (UV) radiation from the sun. The ozone layer keeps about 95% of the sun’s harmful UV radiation from reaching the earth’s surface. This UV filtering effect allows life to exist on Earth and protects us from sunburn, skin and eye cancers, cataracts, and damage to our immune systems. This absorption of UV also makes the stratosphere warm as altitude increases, a trend opposite to that of the troposphere.
Above the stratosphere is the mesosphere and then the thermosphere. Without any heat absorbing materials, the mesosphere is the coldest layer of the atmosphere. The thermosphere is sometimes broken down further into the ionsphere (an area of highly charged particles where auroras occur) and the exosphere (where many satellites orbit). Despite this distinction, the entire thermosphere warms as altitude increases.
Although there is no distinct beginning or end to any of the layers, the transition from one to another is known as a “pause”. For example, the transition from troposphere to stratosphere is called the tropopause. The stratopause divides the stratosphere and mesosphere and the mesopause divides the mesosphere and thermosphere. There is no pause after the thermosphere because it blends into space as the concentration of atmospheric molecules gets lower and lower. / Sketch and label:
http://ds9.ssl.berkeley.edu/LWS_GEMS/3/layers.htm
1  atmospheric layers (4)
1  temperature
1  ozone layer
Practice:
_____ In which level of the atmosphere does weather occur?
A. Troposphere
B. Stratosphere
C. Mesosphere
D. Thermosphere
E. Exosphere
_____ Which level of the atmosphere is the densest?
A. Troposphere
B. Stratosphere
C. Mesosphere
D. Thermosphere
E. Exosphere
_____ What best describes the density of the atmosphere?
A. It increases as you increase in altitude
B. It decreases as you increase in altitude
C. It maintains a constant level throughout the atmosphere
D. It shows fluctuations up and down as you move through the layers of the atmosphere
E. It does not change
_____ What is the importance of the ozone layer?
A. It plays an important role in the greenhouse effect.
B. It reflects solar gamma reaction that would otherwise reach Earth’s surface.
C. It acts as an insulator for the earth and helps to maintain a livable temperature.
D. It absorbs incoming UV rays.
E. It reflects incoming heat back into space.
UNEQUAL HEATING OF EARTH
Factor 1: Variation in Sun’s Angle
Because of Earth’s spherical shape, sunlight strikes the earth at a perpendicular angle only at the equator. As you move away from the equator, the sun’s rays hit the earth at a more oblique angle. When the angle is more oblique, the sunlight must travel a longer distance through the atmosphere. This allows for a lot of energy to be absorbed by the atmosphere, leaving little to hit the earth. Near the equator, sunlight travels only a short distance through the atmosphere, less energy is absorbed, and more energy is left to hit the earth.
Factor 2: Angle of incidence
Air is heated much more at the equator, where the sun’s rays strike directly, than at the poles, where sunlight strikes at an angle and spreads out over a much larger area. These differences in energy input help explain why tropical regions near the equator are hot, why polar regions are cold, and why temperate regions in between generally have warm and cool temperatures.
The intense input of solar radiation in tropical regions leads to greatly increased evaporation of moisture from forests, grasslands, and bodies of water. As a result, tropical regions normally receive more precipitation than other areas of Earth.
Factor 3: Albedo
We will discuss later
EARTH’S TILT AND SEASONS
The earth is tilted 23.5° on its axis. The North Pole is always pointed toward the North Star. During the spring equinox (first day of spring), the equator (0° latitude) is facing directly toward the sun. In this “neutral” position, the equator is getting the most direct sunlight and the rest of the earth is getting indirect sunlight. (Reread the Unequal Heating of Earth summary if necessary.) Six months later, at the autumn equinox, the earth is in the same position except on the opposite side of its revolution around the sun.
During summer and winter, the northern hemisphere is tilted either toward (summer) or away from (winter) the sun. This means during our summer, our angle of incidence is higher and therefore we receive more energy per unit area and experience a higher average temperature. The opposite is true for our winter when we are tilted away from the sun.
Because the earth is only tilted 23.5° and we are at 40° N, we never get the sun’s most direct rays. During our summer, the direct rays shine on 23.5° N latitude, the Tropic of Cancer. During our winter, the direct rays shine on 23.5° S latitude, the Tropic of Capricorn. The area between these two tropics (equatorial region) is always receiving a lot of concentrated solar energy and stays warm year round. But since the warmest area shifts, so does the rain (formed when warm air rises, cools, and releases water as precipitation). Areas just north and south of the equator stay warm but may experience dry seasons during their respective winters.
A common misconception is that the earth is closer to the sun in the summer and farthest from the sun in the winter. Actually, Earth’s perihelion (peri=near, helios=sun) occurs around January 3. Earth’s aphelion (apo=away) occurs around July 4. The difference between these two distances is only about 5 million kilometers (about 3% of the distance to the sun), not enough to affect temperature. Earth’s tilt and its effect on the angle of incidence is the determining factor when it comes to seasons. / Practice:
_____ What region of the earth does the sun hit at the most direct angle?
A. North Pole (90° N) D. 30°-60° S
B. South Pole (90° S) E. Equator (0°)
C. 30°-60° N
_____ Which of the following is not true about the sun’s energy heating the earth?
A. The sun’s rays hit the earth at different angles depending on the latitude.
B. The sun’s rays are concentrated over a smaller surface area at the equator than they are in higher latitudes.
C. The polar regions reflect more sunlight than the tropical regions.
D. The sun’s rays are more strongly reflected in the lower latitude regions.
E. The unequal heating helps to determine an area’s climate.
http://astro.unl.edu/naap/motion1/animations/seasons_ecliptic.html
Use the above website to manipulate the sun and Earth to determine the cause of the seasons.
June marks Summer in the Northern hemisphere draw. Draw the relationship of the sun and Earth during this time. (Shapes not to scale). Draw North America, include the tilt of the axis of Earth (you can use a line through the poles), draw a line to represent the equator, shade the part of Earth that is in “darkness” and include arrows to indicate solar radiation hitting Earth from the sun.

December marks Summer in the Northern hemisphere draw. Draw the relationship of the sun and Earth during this time. (Shapes not to scale). Follow the same directions from above

Practice
_____The primary cause of Earth’s seasons is the
A.  Constant tilt of Earth’s rotational axis with respect to the plane of its orbit around the Sun
B.  Changing distance of Earth from the Sun at different times of the year
C.  Periodic wobbling of Earth on its axis of rotation
D.  Changing relative positions of Earth, its Moon and the Sun
E.  Periodic changes in solar energy output
_____ What latitude receives the most direct sunlight throughout the year?
A. 90° N
B. 30°-60° N
C. 0°
D. 30°-60° S
E. 90° S

EARTH’S ROTATION AND THE CORIOLIS EFFECT
In the northern hemisphere, large air masses generally appear to curve clockwise and in the southern hemisphere, they appear to curve counterclockwise. This curving pattern is a result of the earth’s rotation in an eastward direction as winds move above the surface. The apparent curvature of object traveling long distances on Earth is known as the Coriolis effect. On a global scale, this effect produces steady, reliable wind patterns, such as the trade winds and mid-latitude Westerlies. Ocean currents also experience the Coriolis effect and curve clockwise in the northern hemisphere and counterclockwise in the southern hemisphere.
Imagine you are in space looking down at the North Pole (the center of your field of view). As the earth spins on its axis, the North Pole is moving much slower than the equator because it’s a much smaller area. In 24 hours a point near the North or South Pole (Point A) will not travel nearly as far as a point near the equator (Point B).
An object (like a large mass of air or water) traveling from Point B to Point A will be moving faster than the middle portion of the hemisphere and will end up to the right of Point A. The same object traveling from A to B will be moving slower than Point B and will land behind Point B. Both examples show a clockwise (to the right) curve according to the point of origination. The same effect is seen in the southern hemisphere, with object appearing to curve counterclockwise (to the left) according to the direction they came from.
Large masses of air, moving long distances, like Earth’s atmospheric convection cells are influenced by the Coriolis effect. This is seen in the world’s prevailing winds. The six major wind belts (formed by the six convection cells) all curve clockwise in the northern hemisphere and counterclockwise in the southern hemisphere. The winds on either side of the equator are the Northeast and Southeast trade winds. From 30°-60° are the Westerlies. At the North and South Pole are the polar easterlies. Winds are always named for the direction they come from.


Watch the following video about the Coriolis Effect:
https://www.youtube.com/watch?v=i2mec3vgeaI
If you threw a paper airplane North from Texas what is the most likely place it would land:
A.  California
B.  Nebraska
C.  Delaware
D.  Mexico
An object moving from the Equator south would move to the ______(assuming you were facing South)
Identify the hurricane of the hurricane pictures below (Northern or Southern Hemisphere)