Structure and Temperature The Atmosphere: Structure and Temperature Ch. 17

the state of the atmosphere at a given time and place What is weather? the state of the atmosphere at a given time and place What is climate? observations of weather over a long period of time

A thick blanket of gases surrounding the Earth What is the atmosphere? A thick blanket of gases surrounding the Earth composed of AIR (a mixture of gases)

the source of all clouds and precipitation What gases are in air? Nitrogen (N) 78% Oxygen (O) 21% Also, H2O Vapor, Carbon Dioxide (CO2), and Argon (Ar) in small amounts the source of all clouds and precipitation

The atmosphere rapidly thins as you travel away from Earth until there are too few gas molecules to detect.

What are the layers of the atmosphere?

Troposphere:layer of the atmosphere closest to the Earth- temperature decreases with an increase in altitude where weather happens Stratosphere: second layer of the atmosphere- temperature remains constant to a height of about 20 kilometers where the ozone layer is where airplanes fly

Mesosphere: third layer of the atmosphere- decreasing temperatures with height where meteors burn up Thermosphere: outmost layer of the atmosphere- increasing temperatures due to the absorption of very short-wave solar energy by oxygen where auroras happen

Auroras/Northern Lights

3 oxygen atoms bonded together What is ozone? 3 oxygen atoms bonded together O is an atom of Oxygen (O) O2 is atmospheric Oxygen (O-O) O3 is ozone (O-O-O)

One chlorine atom can destroy 10,000 ozone molecules! Absorbs 99% of harmful ultraviolet rays from the sun ozone layer is about 10 to 20 km thick (found in the stratosphere) thinning is the result of chloroflorocarbons (CFC’s) containing chlorine, fluorine, and carbon One chlorine atom can destroy 10,000 ozone molecules!

This shows a hole in the ozone

What is radiant energy? Almost all of the Earth’s energy comes from the sun and is called radiant energy most reaches the atmosphere and is reflected back to space

Some is absorbed by the Earth and is spread throughout the atmosphere as: Radiation: transfer of energy in form of waves

Energy travels from the sun to the earth by means of electromagnetic waves. The shorter the wavelength, the higher the energy associated with it. This is demonstrated in the animation below. As the drill's revolutions per minute (RPMs) increase, the number of waves generated on the string increases, as does the oscillation rate. The same principle applies to electromagnetic waves from the sun, where shorter wavelength radiation has higher energy than longer wavelength radiation.

What is conduction? direct transfer of energy from one substance to another

What is convection? transfer of energy in a fluid air is a fluid- hot air rises, cool air sinks

As much energy leaves the Earth that comes in ---> Earth’s heat is balanced. What is the greenhouse effect? trapping of the sun’s energy by the Earth

caused by the burning of fossil fuels- coal, oil, and natural gas- adds CO2 into air warming effect may melt glaciers and raise sea levels

Hot air acts like a lid on the atmosphere During the heat of summer, a layer of hot air in which the temperature increases with height often forms high above the Earth. The layer of hot air prevents polluted air near the surface from mixing with cleaner air above it. To make matters worse, the heat helps trap pollution from automobile exhaust and factory emissions.

Houston on a smoggy day (left) and a clear day (right).

Greenhouse gases trap heat like a blanket, causing the Earth’s atmosphere to warm. Carbon dioxide (CO2) released from the burning of coal and other fossil fuels is the predominant greenhouse gas, although methane emissions from agriculture are estimated to be 21 times more effective at trapping heat than CO2. In North Carolina, CO2 emissions have grown steadily along with increases in energy consumption, with emissions of CO2 increasing by more than 30% since 1990. North Carolina’s residential energy consumption is expected to increase by about 50% by 2020. [Source: Understanding Climate Change for North Carolina]

From website http://www.2think.org/keeling_curve.shtml Another graph showing CO2 increases over time. From website http://www.2think.org/keeling_curve.shtml

What are pollutants? Air pollutants: airborne particles and gases that occur in concentrations large enough to endanger the environment primary pollutants: emitted directly from an identifiable source transportation vehicles account for nearly half!

secondary pollutants: form in the atmosphere where reactions take place among primary pollutants and other substances

How environmentally safe is your car? Emissions from transportation vehicles account for nearly half the primary pollutants by weight. How environmentally safe is your car?

Air Pollution from Coal-burning Power Plants SO2 NOX Acid rain Visibility degradation Fine particulates Ground level ozone Fine particle pollution Two of the primary pollutants generated by coal-fired power plants are oxides of nitrogen, or NOx, and sulfur dioxide. SO2 and NOx combine in our atmosphere to produce fine particulate matter, or “soot.” Additionally, NOx reacts with compounds in the atmosphere in the presence of sunlight to form ground-level ozone, or “smog.”

What is the Clean Air Act? Passed in 1970 and strengthened in 1990 Gives the Environmental Protection Agency the authority to regulate automobile emissions Eliminated lead gas

Global Warming Once a thick tongue of ice that poured into the Gletsch valley (inset), the Rhone Glacier has shrunk dramatically since 1850. In 2003, the Rhone Glacier and other Swiss glaciers retreated more than any other year since scientists began taking measurements in the 1800s. While the summer’s extreme temperatures caused the glaciers to thin more than usual, scientists say that the glaciers retreated in response to long-term warming.

Vostok Ice Core Record - 4 Glacial Cycles . . . . . . . . . . The key message from this graph is that temperature, CO2 concentration and temperature have tracked together pretty closely over 420,000 years. That includes a big part of human history and all of recorded human history. Critical thinking – Does the fact that these items track together mean that CO2 concentration causes the Earth’s temperature to change? Homework – find out what physics says about the ability of CO2 to capture heat. What wavelengths does CO2 capture most effectively? What wavelengths come from the sun to the Earth? What wavelengths are emitted from the Earth’s surface toward space? Source: Petit et al., 1999, Nature 399, p. 429-346.

Greenhouse Gas Emissions Burning Fossil Fuels Greenhouse Gas Emissions Air Pollution Climate Change We can expect to see increases in asthma rates and other respiratory illnesses, increases in premature deaths as a result of heart and lung disease, increases in infectious diseases -- particularly diseases carried by insects such as mosquitoes and ticks which may benefit from longer growing seasons. Increases in extreme weather events will lead to more injuries and increased damage to infrastructure -- buildings, roads, trains, electrical lines, water supplies, etc. Asthma Attacks Other Respiratory Illnesses Premature Death from Lung and Heart Diseases Heat-Related Deaths Infectious Diseases Injuries from Extreme Weather Events Allergies

the more energy the molecules have, the hotter it feels What is temperature? average kinetic energy of the atoms or molecules in a particular substance the more energy the molecules have, the hotter it feels the energy transferred from one object to another because of a difference in their temperatures heat?

What are isotherms? lines on a map that connect places that have the same temperature

What is a thermometer? instrument that measures temperature •alcohol and mercury thermometers used (mercury more accurate)

water freezes at: 0ºC or 32 ºF water boils at: 100ºC or 212ºF

Why does temperature vary?  Land and Water • Land heats more rapidly and to higher temperatures than water. Land also cools more rapidly and to lower temperatures than water.

Mean Monthly Temperatures for Vancouver and Winnipeg Makes no sense without caption in book

Why Temperatures Vary  Geographic Position • The geographic setting can greatly influence temperatures experienced at a specific location.

Mean Monthly Temperatures for Eureka and New York City Makes no sense without caption in book

Mean Monthly Temperatures for Seattle and Spokane Makes no sense without caption in book

Why Temperatures Vary  Altitude • The altitude can greatly influence temperatures experienced at a specific location.

Mean Monthly Temperatures for Guayaquil and Quito Makes no sense without caption in book