GEOG 306 Exam #1
Isotherm Map
lines on a map connecting points of equal temperature. Any point ON a line would be estimated to be that exact temperature, while points located between lines must be somewhere between those two temperatures.
Weather
the state of the atmosphere at a given time and place. It is what you are actually experiencing at any given time.
Combine Revolution and Tilt to Understand Seasons
- The vertical ray is not always at the Equator. - As the Earth revolves around the sun, the latitude of the vertical ray migrates. - It migrates north in our summer, and then south in our winter.\ - In other words, the Northern Hemisphere tilts towards the sun in June and away in Dec. - It moves as far north as the Tropic of Cancer - 23 1/2 °N (June Solstice) - It moves as far south as the Tropic of Capricorn - 23 1/2 °S (December Solstice) - It crosses the Equator (0°) twice during the year on the March and September Equinoxes!
ionosphere
A layer in the lower thermosphere where high energy solar radiation charges (literally electrifies) atoms of oxygen and nitrogen. This occurs mostly towards the poles creating the aurora borealis (northern lights) and the aurora australis (the southern lights).
If the maximum temperature for a particular day is 26°C and the minimum temperature is 14°C, the daily mean would be: A) 20°C B) 13°C C) 12°C D) 40°C E) cannot be determined with this data..
A) 20°C
On approximately what date will the sun pass directly overhead at 23.5 degrees North latitude? A) June 21. B) March 21. C) September 22. D) December 21. E) July 4.
A) June 21.
Low sun angles result in reduced solar energy at Earth because: A) energy is diffused (spread out) over a larger area. B) the Sun - Earth distance is extremely high. C) surface absorption is reduced. D) daily hours of sunshine are shorter. E) the solar rays are passing through much less atmosphere
A) energy is diffused (spread out) over a larger area.
The annual temperature range may be described as: A) the difference between the average temperatures of the warmest and coldest months. B) the sum of the average temperatures for each month of the year. C) the difference between maximum and minimum temperatures during the period of one month. D) the difference between the hottest and coldest temperatures measured during an entire year. E) the same as the annual average temperature.
A) the difference between the average temperatures of the warmest and coldest months.
If a radiosonde (weather balloon) measures a surface temperature of 50.0°F, what will the temperature be 6000 feet above the surface? (Base your answer on the normal lapse rate.) A. 29.0°F B. 39.0°F C. 44.0°F D. 50.0°F E. 71.0°F
A. 29.0°F
The normal lapse rate is: A. The average air temperature decrease observed from Earth's surface toward space. B. The exact air temperature change measured from Earth's surface toward space at a specific time and place. C. The increase in global atmospheric carbon dioxide. D. The decrease in stratospheric ozone caused by use of chlorofluorocarbons (CFCs). E. The rhythmic drumming noise caused by molecular collisions in the upper atmosphere.
A. The average air temperature decrease observed from Earth's surface toward space.
Earth's current angle of inclination (or tilt) is: A) 15° B) 23.5° C) 66.5° D) 90° E) 120°
B) 23.5°
An isotherm on a map: A) passes only through known weather station sites. B) represents the coldest place on the map. C) represents the warmest place on the map. D) identifies all places that have the same annual mean temperature. E) is a line which connects points of equal temperature.
E) is a line which connects points of equal temperature.
What is true about latent heat? A. It is measured in the same way as sensible heat. B. It is only detectable in the stratosphere. C. It is a form of potential chemical energy. D. It is a form of kinetic nuclear energy. E. It is absorbed by water when water melts and evaporates.
E. It is absorbed by water when water melts and evaporates.
Urban Heat Island
Large urban areas tend to be warmer than their immediate surrounding countryside. This occurs for several reasons: - City surfaces and building materials (concrete, asphalt, glass, etc) tend to absorb and store more heat than the surrounding countryside (trees, dirt, rocks, etc). - City surfaces quickly funnel precipitation runoff away from the city. This results in a huge reduction in evaporative cooling. In other words, instead of being hidden as latent heat through evaporation, a radiation surplus is much more likely to be felt as sensible heat. - City activities generate many sources of waste heat (e.g. factories, heaters, power plants, vehicles, etc) - City smog acts as a nighttime blanket, absorbing and re-radiating Earth's longwave energy back toward the surface.
Temperature Controls
Latitude, Elevation, and Proximity to Ocean
Mechanical Thermometers
Mechanical thermometers rely on the expansion and contraction of a substance which occurs when the substance changes temperature. Such substances include mercury, alcohol, and metal.
Chloropleth Map
Shows temperatures based on shading and or colors which are proportional to the temperature values.
Temperature
a measure of the level of kinetic energy is a substance - in other words, how fast the molecules are vibrating.
Meteorology
a more formal term for the scientific study of the atmosphere and of the phenomena that we normally call weather. It originally referred to debris falling from space (like a meteorite) but now only refers to Earth and atmospheric phenomena.
Temperature Gradient
refers to the temperature difference across a certain distance. A high gradient means that there is a huge difference (shown by tightly spaced isotherms), while a low gradient means that there is a very low difference (shown by widely spaced isotherms).
Latent Heat
the heat involved in the change of phase of water from solid to liquid to gas. It cannot be measured by a thermometer. When water melts or evaporates, latent heat is going into the water. When water condenses or freezes, latent heat is coming out of the water.
Shortwave (Solar) vs Longwave (Earth)
- Many people think that the sun heats our atmosphere, but in reality the sun is first absorbed at the surface, causing it to heat. Only then does the surface heat the lowest atmosphere by conduction. This is because our atmosphere mostly transmits shortwave (solar) radiation rather than absorbing it. - For longwave radiation it is basically the opposite. The longwave radiation emitted by Earth is mostly absorbed by our atmosphere, rather than transmitting all the way out to space. - For both of these reasons listed above, it is appropriate to think of the troposphere (the lowest layer of the atmosphere) as being heated from below.
Annual Cycle
- The annual cycle of temperature change during the year is the result of seasonal changes in sun angle and hours of daily sunlight. - There is virtually no change in annual temperature near the equator, where there is little change in sun angles and hours of sunlight per day. Conversely, the farther one gets from the equator, the greater seasonal variation there is in angles, hours, and thus temperature. - As with the daily temperature cycle, the highest and lowest temperatures of the year generally occur later than the peak radiation surpluses and deficits.
Daily Cycle
- The daily cycle of temperature is caused by Earth's rotation, which causes most locations to rotate into sunlight and darkness during any 24 hr period. - When the sun "rises" the sun angle increases causing the radiation surplus to increase until its peak at solar noon. - The temperature continues to rise, though, as long as there is still a radiation surplus (usually until 3 or 4 in the afternoon). - At this point radiation outputs exceed inputs, causing a radiation deficit which leads to cooling.
Ocean Currents (wind pushes water!)
- The world's ocean currents are massive heat - distribution systems, moving warm water towards the poles (where it loses the heat) and returning cold water toward the tropics (where it gains it again). - For reasons explained later, cold currents tend to flow along west coasts, while warm currents tend to flow along east coasts. This has a direct impact on coastal climates in these locations.
Annual Mean Temperature Range Map
- This map shows the difference between average temps in the warmest and coldest months. - Low latitude marine locations have the lowest annual ranges (minimal seasonal change). - High latitude continental locations have the highest annual ranges (max seasonal change).
January and July Mean Temperature Maps
- You should note the major patterns which result from the temperature controls previously discussed. - It should be obvious that temperature generally decreases from the equator toward the poles. - It should also be obvious that extreme hot and cold locations occur on land surfaces. - Lastly, you should be able to find locations at the same latitude where marine and continental influences are evident.
Astronomical vs Climatological Seasons
Astronomical seasons are based on the dates of the solstices and equinoxes, while the climatological seasons are simply based on the months of the year.
Mie Scattering (causes red/orange sunsets)
At sunrise or sunset when the sun is low on the horizon, the incoming solar energy is actually passing through more atmosphere than when the sun is high above. As a result, virtually all of the shorter wavelengths (blue/violet) are fully scattered (i.e. completely filtered out) before reaching Earth. The only wavelengths remaining are red and orange.
Atmospheric Interference
Atmosphere reflects and absorbs solar energy. This means that the Sun's energy is weakened on its way to Earth. Higher sun angles pass through less atmosphere (and have less interference), while lower sun angles pass through more atmosphere (and have more interference).
Which is NOT a quality of water that causes it to heat and cool more slowly than land? A) It has a higher specific heat than land (e.g. dirt and rock). B) It tends to be much heavier than land (e.g. dirt and rock). C) It absorbs and releases latent heat (hidden heat), while land does not. D) It is transparent, while land is not. E) It easily flows and mixes, while land does not.
B) It tends to be much heavier than land (e.g. dirt and rock).
Generally speaking, marine locations such as San Francisco have <_____________> winters and <____________> summers when compared to continental locations at the same latitude (such as Wichita, Kansas). A. <cooler>...<warmer> B. <warmer>...<cooler> C. <warmer>...<warmer> D. <cooler>...<cooler>
B. <warmer>...<cooler>
Which best describes the vertical pattern of atmospheric pressure? A. It is lowest at Earth's surface and increases toward space. B. It is highest at Earth's surface and decreases toward space. C. It remains constant (unchanged) from Earth's surface toward space. D. There is no detectable pattern. E. It fluctuates randomly from Earth's surface toward space.
B. It is highest at Earth's surface and decreases toward space.
The Solution
By the mid-1980s, research had made it clear that CFCs were responsible for damaging the ozone. In 1987 representatives from all over the world joined together in Montreal, Canada and agreed to phase out the use of CFCs. This agreement (known as the "Montreal Protocol") is widely recognized as one of the greatest successes in international environmental cooperation. Ozone destruction has slowed significantly and, in come cases, reversed.
How is the annual mean temperature calculated? A) It is the average of the warmest and the coldest temperatures recorded during that year. B) It is the average of the warmest and the coldest monthly mean temperatures. C) It is the average of all 12 monthly mean temperatures. D) It is the average of all the daily mean temperatures for the year. E) It is the average of all the monthly mean temperatures for the last 10 years.
C) It is the average of all 12 monthly mean temperatures.
If a radiosonde (weather balloon) rises 5000 feet above the surface and measures a temperature decrease of 25.0 F°, what is the environmental lapse rate? A. 2.5F° / 1000ft B. 3.5F° / 1000ft C. 5.0F° / 1000ft D. 10.0F° / 1000ft E. 25.0F° / 1000ft
C. 5.0F° / 1000ft
In general, low latitude areas (near the equator) experience a radiation <_________> and high latitude areas (near the poles) experience a radiation <__________>. A. <surplus> ...... < surplus> B. < deficit > ...... < deficit > C. < surplus> ...... < deficit > D. <deficit > ...... < surplus>
C. < surplus> ...... < deficit >
Which is a true statement about the heat index? A. Increased humidity causes the air temperature to increase significantly. B. Wind makes the human body feel colder because it blows the heat away. C. Increased humidity causes the human body to feel warmer than it would be if the air were drier. D. It is measured using specially designed thermometers. E. It is only a factor at temperatures below 70°F
C. Increased humidity causes the human body to feel warmer than it would be if the air were drier.
The average temperature in Sacramento for the month of July is 75.5° F. This is an example of what type of data? A. weather B. meteorology C. climate D. pressure E. atmospheric
C. climate
In terms of hours of daily sunlight and angle of sun above the horizon, which conditions will provide the highest inputs of solar radiation at any particular location on Earth? A. low hours, low angles B. low hours, high angles C. high hours, high angles D. high hours, low angles
C. high hours, high angles
Celsius
Celsius sets the melting point of ice at 0°C and the boiling point of water at 100°C
Albedo Differences
Cloudy vs Clear: - Clear skies (low albedo conditions) result in overall higher temps and higher daily temperature ranges. This is because during the day maximum sunlight (shortwave) reaches the surface (maximizing heating), while at night most longwave escapes to space (maximizing cooling). - Cloudy skies (high albedo conditions) result in overall lower temps and lower daily temperature ranges. This is because during the day minimum sunlight (shortwave) reaches the surface (reducing heating), while at night most longwave is absorbed by clouds and radiated back toward the surface (minimizing cooling). Snow/Ice vs Rock/Soil: - Snowy and icy surfaces are actually colder than nearby ice/snow free surfaces because so much of the incoming sun's energy is simply reflected back toward space.
What is the most basic cause of heating at Earth's surface? A) warm air blown in from other locations B) heat conducted from Earth's deep interior C) a net deficit of radiation at the surface D) a net surplus of radiation at the surface E) sunspots and other solar flaring activity
D) a net surplus of radiation at the surface
Earth's perihelion: A) coincides with the Northern Hemisphere summer solstice. B) is the basic reason we have summer in the Northern Hemisphere. C) coincides with the Southern Hemisphere winter solstice. D) occurs when Earth is closest to the Sun. E) only occurs once every ten years.
D) occurs when Earth is closest to the Sun.
From June 21 to December 21 in Sacramento, hours of sunlight per day are <_________> and angle of sun above the horizon are <__________>. A. <increasing> ...... < increasing > B. < increasing > ...... < decreasing > C. < decreasing > ...... < increasing > D. <decreasing> ...... < decreasing >
D. <decreasing> ...... < decreasing >
Which is the most abundant gas in the troposphere? A. oxygen B. carbon dioxide C. water vapor D. nitrogen E. argon
D. nitrogen
Hours Per Day (How long is it out?)
Daylength is a critical factor determining how much energy is received at any given location on earth. The longer the sun is in the sky, the more energy is received. The shorter the sun is in the sky, the less energy is received...
Earth is closest to the Sun during: A) Northern hemisphere autumn. B) Southern hemisphere autumn. C) Southern hemisphere winter. D) Northern hemisphere summer. E) Northern hemisphere winter.
E) Northern hemisphere winter.
Which of these surfaces would likely have the highest albedo? A. Rainforest B. Green pasture. C. Blacktop parking lot. D. Sandy beach. E. Snow covered field
E. Snow covered field
Which layer of the atmosphere do humans live in? A. ionosphere B. thermosphere C. mesosphere D. stratosphere E. troposphere
E. troposphere
Rotation
Earth makes one full rotation (spin) on its axis every 24 hours. This defines one full day.
Revolution (Orbit)
Earth travels around the Sun, making one full journey every 365.25 days.
Earth's Tilted Axis
Earth's axis is tilted 23 1/2 ° from a right angle with the plane of the ecliptic; the North axis is always pointed to a fixed point in space (Polaris, also called the North Star).
Electric Thermometers (thermistors)
Electric thermometers rely on changes in the rate of electricity flow which occur as temperature increases or decreases. These types of thermometers detect temperature changes almost immediately and are ideal for digital displays and for recording and sending data electronically.
Energy and Related Concepts
Energy is something that can do work - generally it can make something move... Energy can be chemical (food, gasoline), thermal (hot air or water), nuclear (the sun), radiant (light), or gravitational.
Fahrenheit
Fahrenheit sets the melting point of ice at 32°F and the boiling point of water at 212°F
Daily Range = max - min
Gives us an idea of how extreme the temperature differences were for the day.
Annual Range = highest monthly mean - coldest monthly mean
Gives us an idea of how extreme the temperature differences were for the entire year.
Daily Mean = sum of 24 hourly measurements ÷ 24 (or [max + min] ÷ 2)
Gives us one temperature to represent the whole day.
Monthly Mean = sum of daily means ÷ number of days in the month
Gives us one temperature to represent the whole month.
Annual Mean = sum of monthly means ÷ 12
Gives us one temperature to represent the whole year.
Heat (or thermal energy)
Heat is the energy contained in a substance based on its temperature. It is important to note that a small amount of a very hot substance will likely NOT contain as much total heat as a huge amount of a lukewarm substance. For example, there is more heat in a lukewarm swimming pool than there is in a mug of boiling water.
Angles Above the Horizon (How high is it in the sky?)
Higher sun angles (i.e. when the sun is higher in the sky) deliver more energy at Earth's surface compared to lower angles. This occurs for two reasons: Beam Concentration: Higher sun angles are more concentrated (focused) while lower sun angles are more diffused (spread out). Atmospheric Interference: Atmosphere reflects and absorbs solar energy. This means that the Sun's energy is weakened on its way to Earth. Higher sun angles pass through less atmosphere (and have less interference), while lower sun angles pass through more atmosphere (and have more interference).
Beam Concentration
Higher sun angles are more concentrated (focused) while lower sun angles are more diffused (spread out).
Theory
In everyday terms, people often use the word theory to refer to something that is unsure or untested (like a wild conspiracy theory). In science, a theory is a scientific explanation that has been extensively tested, researched, and scrutinized and still found to be true and accurate. A scientific theory is often predictive (e.g. Smoking causes lung cancer, so we should be very concerned about someone who has smoked 2 packs per day for 20 years.)
Earth's systems
In science, a system can be anything that we can draw a boundary around (like a lake, a cloud, Earth, etc). When we study systems we look at the energy and matter that goes into them (called inputs) and the energy and matter that leaves them (called outputs). We also try to understand how energy and matter moves around within a system.
Biosphere
Includes all life on Earth. Generally exists where the atmosphere, hydrosphere, and lithosphere intersect. Generally extends to the bottom of the ocean and about 20-30 miles into the atmosphere.
Hydrosphere
Includes all water on Earth, both frozen and unfrozen. Technically, all of the ice is called the cryosphere.
Atmosphere
Includes the layer of gasses surrounding Earth. The atmosphere is approximately 500km (300 miles) tall.
Lithosphere
Includes the solid, mineral portion of Earth.
Pressure of the Atmosphere
It is critical to understand that atmospheric pressure (the "weight" or force of the air pushing on us from above) is highest at Earth's surface, and decreases upwards toward space. In other words, the air is "thickest" at the surface and gets increasingly thinner as you move away from Earth. Beyond about 22 miles (36 km) there is almost no air left. Pressure can be measured in different units. At Earth's surface, the pressure averages a little over 1000 millibars (a millibar is a measure of force). This is the same as 14.7 pounds per square inch (14.7lbs/in2) or 1 kilogram per square centimeter (1kg/cm2). See slide showing pressure changes with altitude.
Kelvin
Kelvin sets the melting point of ice at 273°K and the boiling point of water at 373°K. It is based on the celsius scale, but sets 0°K as absolute zero, a theoretical point so cold that molecules cease to vibrate (i.e. the absence of thermal energy). Kelvin does not go below zero.
Latitude (temp control)
Latitude is the most obvious and important temperature control. Temperatures are generally warmest at the lowest latitudes (at or near the equator) because that is where the sun angles are - on average - highest. Temperatures generally decrease moving away from the equator (toward the poles) because average sun angles decrease as latitude increases.
Prevailing Wind Direction (most common wind direction)
Locations are also influenced by where their wind comes from. A location receiving wind from the ocean (e.g. Oregon and Washington) experience much warmer winters that the same latitudes (e.g. New York, Massachusetts) receiving wind from a cold continental land mass.
Modern Composition (What is it made of now?
Nitrogen (N2; approx. 78%): Important to life on Earth, but doesn't affect the weather much. Oxygen (O2; approx. 21%): Important to life on Earth, but doesn't affect the weather much. Argon (Ar; approx. 1%): Inert (non-reactive); doesn't do much. Carbon Dioxide (CO2; approx. 0.0400% or 400ppm): Though it exists in relatively small quantities, carbon dioxide is significant because it is an extremely efficient absorber of energy (i.e. it is a greenhouse gas). This means that it has an incredibly strong influence on the temperature of the atmosphere. Due to the burning of fossil fuels by humans, levels of carbon dioxide in the atmosphere have been steadily rising since the Industrial Revolution began (about 1750). This is resulting in anthropogenic global warming (i.e. warming caused by humans). See slide showing graph of increasing CO2 in our atmosphere since the 1950s. Water Vapor (H2O; highly variable): Water vapor is also referred to as humidity. It plays a massive role in controlling Earth's weather and climate. Like carbon dioxide, it is considered a greenhouse gas. Aerosols: Aerosols are extremely tiny solid or liquid particles floating in the air. They may include smoke, dust, volcanic ash, salt particles, and pollen. They are important in cloud formation and can also affect how much sun is reflected and/or absorbed. Ozone (O3; highly variable) Its Natural Role: Ozone is a form of oxygen, but NOT the kind we breathe (which is O2). It is generally formed and found in the stratosphere, between about 10 and 50 kilometers above Earth's surface. It is responsible for absorbing (blocking) dangerous ultraviolet (UV) radiation from the Sun. Without it, life on Earth would be nearly impossible.
The "Rules" of Scientific Inquiry
Observation Comes BEFORE Conclusions (Science is not used to "prove" beliefs.) Must Follow Accepted Science (Magic and miracles are not "allowed" in science.) Must Be Repeatable and Verifiable (You must be able to show others - generally there are no secrets in science.) Must Be Willing to Change Your Mind (When presented with new, contradictory evidence, scientists can't just ignore it.) Science Continually Asks New Questions... (as opposed to only attacking science they don't agree with.)
Higher Latitudes (i.e. Polar, near the north and south poles)
On average, higher latitudes experience lower sun angles. Thus, higher latitudes receive less energy and are generally colder.
Lower Latitudes (i.e. Tropical, near the Equator)
On average, lower latitudes experience higher sun angles. Thus, lower latitudes receive more energy and are generally warmer.
Origins (Where did it come from?)
Outgassing Happened First (4+ billion years ago): The gasses making up Earth's early atmosphere (4+ billion years ago) was expelled from volcanoes. This process is called outgassing. Oxygen Came Later (3.5 billion years ago): The first oxygen was produced 3.5 billion years ago through photosynthesis by blue-green algae throughout the world's oceans.
Potential vs Kinetic Energy
Potential energy is stored energy (not currently doing work), while kinetic energy is energy that this actively doing work (moving something - even molecules!).
Reflected / Scattered
Radiation that is reflected is bounced in the opposite direction, while radiation that is scattered is bounced in random directions.
Transmitted
Radiation that passes through a substance without being affected is transmitted. As an example, on a bright, clear sunny day, our atmosphere transmits sunlight very well. Alternately, a brick wall does NOT transmit solar radiation (sunlight) at all.
The Annual Numbers
Review and understand the slide showing inputs and outputs of radiation and heat for the 1) entire Earth/Atmosphere system and for 2) Earth's surface and 3) its atmosphere. For each of these three systems, notice that the numbers show that inputs equal outputs (i.e. there is a balance). This is generally true if you are only looking at a few years or few decades worth of data. Eventually, though, systems will show long term imbalances which result in heating or cooling. Currently the entire Earth/Atmosphere system is experiencing an imbalance (specifically a surplus) which is why we are warming!
Earth's Energy Budget
Satellites and ground instruments allow us to fairly accurately measure radiation inputs and outputs for the entire Earth/Atmosphere system. Additionally these instruments can track inputs and outputs for Earth's surface and its atmosphere. Commonly these measurements are based on the total input we receive from the sun, which is arbitrarily set at 100 units (just to make it easier). All units are based on that number.
Normal Lapse Rate (6.5C° / 1000meters or 3.5 F° / 1000feet)
Starting at Earth's surface, the temperature decreases as you move toward space. The average rate of decrease is called the normal lapse rate; the values are shown above. The transition zone where the temperature no longer decreases is called the tropopause. This is basically the TOP of the troposphere.
Ozone Destruction
Starting in the 1930s, humans began producing chemicals called chlorofluorocarbons (CFCs). It took decades for us to realize that CFCs were floating into the stratosphere and destroying our protective ozone layer. This allowed dangerous levels of UV radiation to reach Earth's surface and resulted in increased rates of skin cancer and eye damage in places around the world.
Elevation temp control
Studying the normal lapse rate taught us that, on average, temperatures are highest at Earth's surface and decrease toward the tropopause. In other words, it generally gets colder as you move upward toward space. In the case of mountains, they are basically "bumps" which poke up into the cold air of the upper troposphere.
Temperature of the Atmosphere
The atmosphere has a very distinct thermal structure. In other words, it has multiple layers, each with distinctly different temperature patterns. See slide showing these layers.
Perihelion
The day when Earth passes closest to the Sun each year. Occurs on or about January 3rd each year.
Aphelion
The day when Earth passes farthest from the Sun each year. Occurs on or about July 4th each year.
Environmental Lapse Rate
The environmental lapse rate (ELR) is similar to the normal lapse rate, but instead of being an average, it refers to an actual measurement taken at a specific place and time. The normal lapse rate is actually the average of 1000s of environmental lapse rates. Such measurements are taken with a weather balloon, technically called a radiosonde. See slide showing a radiosonde. ELR = [temperature decrease] ÷ [elevation difference] x 1000
The Greenhouse Effect
The explanation above basically describes Earth's greenhouse effect. Specifically, there are certain gasses which are excellent natural absorbers of longwave radiation - CO2 and H20 vapor. Basically these gases allow us to hold onto the sun's heat, which is especially important at night. The problem now with human-caused increases of greenhouse gases is that we are holding onto too much heat. We have strengthened the greenhouse effect and caused global warming.
The Electromagnetic Spectrum
The sun gives off wavelengths less than 3μm; we will generally call this shortwave. Earth and its atmosphere give off wavelengths greater than 3μm; we will generally call this longwave.
Troposphere
The troposphere is the lowest layer of the atmosphere - the layer we live in and the layer where our weather takes place. It averages about 12km (7.5miles) thick - it is thinner at the poles and thicker at the Equator.
The Latitudinal Energy Budget
There is a very distinct pattern (see slide) in Earth's radiation budget when comparing different latitudes. Specifically, the lowest latitudes (near the equator) have the highest radiation surpluses (inputs are much higher than outputs), while the highest latitudes (near the poles) have the highest radiation deficits (outputs are much higher than inputs). This is almost entirely due to the fact that average sun angles are highest at the Equator and decrease toward the poles...
Instrument Shelter
To get accurate readings of AIR temperature, thermometers MUST be installed in a shaded container which allows air to freely flow through. When a thermometer is exposed to the direct sunlight, the thermometer itself experiences an extreme radiation surplus. In this case the reading is NOT representative of the air temperature.
What Happens to Incoming Solar Radiation (called Insolation)?
Transmitted, Absorbed, or Reflected/Scattered
Radiation
Unlike conduction or convection, radiation requires NO molecules to transfer heat; it can move energy through the vacuum (nothingness) of space. It can be thought of as infinitely small energy packets that travel in waves from one place to another. In our everyday experience, everything emits (gives off) radiation.
The Concept of Radiation Wavelength
Wavelength is defined as the distance from the top of a wave to the top of the next wave. These wavelengths are extremely small, being measured in micrometers (μm). A micrometer is 1/1000th of a millimeter. As a rule, the wavelength emitted by any substance increases as its temperature increases. In other words, hot things give off shorter wavelengths, while colder things give off longer wavelengths.
Absorbed
When radiation is absorbed at a surface or by a substance, it is essentially converted to thermal energy (basically, heat). This causes the molecules to vibrate faster and faster.
Rayleigh Scattering (causes blue skies)
When the sun is higher in the sky, the shorter wavelengths (blue/violet) are selectively scattered by atmospheric gasses. Thus, the sky appears blue to us here on Earth.
Hypothesis
a proposed explanation for something that we observe in the natural world. It can be in the form of a statement (e.g. Clouds are composed of small liquid droplets.) or a question (e.g. Is a cloud composed of small liquid droplets?). Either way, a hypothesis MUST be testable. In other words, we must have a way to answer the scientific questions we ask.
Mesosphere
he layer above the stratosphere. It is not well explored. In this layer, the temperature decreases toward space. The top of the mesosphere is called the mesopause.
Sensible Heat
the heat measured by a thermometer - it is the heat we actually feel. On a molecular level, it is the heat that is vibrating the molecules of any substance (e.g. dirt, rock, air, etc)
Thermosphere
the layer above the mesosphere. In this layer, the temperature increases toward space, reaching temperatures over 1000°C (1800°F) This is because the air here absorbs extremely short wave, high energy solar radiation. It is important to note, THOUGH, that the air is so thin that even at high temperatures it contains very little heat. It would definitely not burn you.
Stratosphere
the layer above the troposphere; it is where our protective ozone layer (often called stratospheric ozone) is located. In this layer, the temperature increases toward space. The top of the stratosphere is called the stratopause.
Climate
the long-term average of various weather conditions (e.g. temperature, precipitation, humidity, etc). As an example, it could be cold and rainy in Sacramento in late-July, but we certainly don't expect that.
Wind Chill
the perceived decrease in air temperature felt by the human body as a result of wind. It is NOT the temperature measured by a thermometer, but rather an estimate of how much colder humans feel when their skin is exposed to the wind. This is because wind continually carries away the thin layer of heat conducted into the air by exposed skin, causing the body to continually try to replace it.
Heat Index
the perceived increase in air temperature felt by the human body as a result of increased humidity. It is NOT the temperature measured by a thermometer, but rather an estimate of how much warmer humans feel when they are exposed to increasingly humid conditions. This is because humid conditions significantly weaken the human body's natural ability to cool down through sweating and evaporation.
Albedo (albedo = solar reflected ÷ total solar received x 100)
the proportion (percentage) of solar radiation that is reflected by a surface compared to the total solar radiation received at that surface. Lighter surfaces have higher albedos while darker surfaces have lower albedos.
Convection (heat transfer in a moving substance)
when a heated substance (air or water) flows from one place to another, carrying the heat with it. In nature, winds and ocean currents are major mechanisms of convection.
Conduction (heat transfer through touch)
when heat moves from molecule to molecule simply because they are touching each other. In other words, when a hot molecule begins vibrating faster, it causes the molecules next to it to vibrate faster as well.
