Chapter 19 - Atmosphere

Troposphere

  • Lowest Layer

  • “Human Layer”

  • weather takes place

  • Here, a low ozone layer is BAD (red haze in densely populated areas like Shanghai)

  • 80% of total mass of atmosphere

  • Temp AND density decreases with altitude (molecules to heavy to go up)

    • Temp drops about 7 degrees Celsius for every 1 kilometer you go up

Stratosphere

  • Clear, dry layer above TropoPAUSE

  • “Cruising altitude” Above the clouds, so no weather takes place

  • Cold at the top of Tropopause, but warms as it ascends

  • OZONE IS HERE and it ABSORBS UV LIGHT (favorite food per se), some energy released as heat

Mesosphere

  • 3rd Layer

  • Meteor Showers here

  • temp drops again with increase in altitude

Thermosphere (and Isosphere)

  • 4th layer (almost outer space!)

  • Upper, thin part of thermosphere

  • Northern Lights here → ions interact with different gases, creating stunning displays of natural light known as auroras.

  • very few (ionized) atoms here, so they get a TON of solar radiation, temps can be up to 1000 degrees Celsius.

    • Sun spots (eruptions on the surface of the sun) send out radiation that charges atoms → ions

  • Gas Layers separated based off DENSITY (least to most)

    • Hydrogen

    • Helium

    • Oxygen

    • Nitrogen

Radiation - Energy transfer thru SPACE; doesn’t require a medium

  • Entire electromagnetic spectrum

Conduction - Energy transfer thru CONTACT

  • Think of stepping on a hot blacktop or touching a hot pan

Convection - Energy transfer thru LIQUID OR GAS

  • Hot air rises, cold air sinks

2 MAIN GASSES In the Troposphere

  • (78%) Nitrogen: Playing a crucial role in weather patterns and climate.

  • (21%) Oxygen: Makes up about 21% of the troposphere, essential for respiration in living organisms.

Other Gasses

  • (1%) Argon and Carbon Dioxide

Trace Gasses

  • Helium

  • Hydrogen

  • Neon

The atmosphere has LOTS of water vapor at the SURFACE, but less as you go up. This change occurs at the 80 kilometers point if you were to travel up a mountain

Particles in the Atmosphere

  • Salt crystals

  • Soot from fires

  • Pollen

  • rock grains

  • dirt

There is less Carbon dioxide in the summer because plants absorb more of it for photosynthesis, hence contributing to a decrease in overall atmospheric levels during this time. This is reversed in the winter because plants are dormant and photosynthesis rates decrease, leading to an accumulation of carbon dioxide in the atmosphere.

Year Without a Summer - 1815 - Volcano eruption in Indonesia → Ash and dust blocked sun’s rays, causing temp to fall.

Volcanoes helped form earth’s early atmosphere

  • Pre-atmos = CO2, Sulfur dioxide, water vapor, nitrogen

  • Oxygen ← Sunlight split water molecules into Hydrogen and oxygen

  • Oxygen increased when early life photosynthesized and released oxygen as a byproduct, significantly altering the composition of the atmosphere and paving the way for the evolution of aerobic organisms.

Recycling of atmospheric Materials

  • earth has a good recycling system

  • Dust, gas, cloud, particles, etc always being moved from atmosphere to bio/geo/hydrosphere

  • Balanced maintained → Law of conservation of mass, what goes in must come out

  • Green House gases risen almost 20% in 20 years because of global warming

Heat + the Atmosphere

  • Some energy can drive the weather, like sunlight

  • RADIATION, CONDUCTION, CONVECTION


Heat and Temp

  • Temp = measure of AVEREGE kinetic energy because atoms are always moving

    • Boiling water molecules move faster and have more kinetic energy

    • Thermometers measure TEMP, not heat

  • Heat = measure of TOTAL kinetic energy

    • Large cup of tea has more heat than a small one even at the same temp

    • Always wants to flow from high temp substance to low temp substance

Insolation in atmosphere

  • Insolation/I.S.R - incoming solar radiation

  • Different ways earth absorbs and emits ISR

    1. Absorption - absorbs gasses, earths atmosphere, air

    2. Scattered - scattered by collisions w/ gas molecules and dust in atoms

    3. Reflected - reflected back into space

      Radiation balance

Global Heat Budget

  • If this is in balance, global temps are constant. If not, earth is too hot/cold

    • Like credit card debt / overspending

    • We’re making more fossil fuels than earth can fix

Greenhouse Effect (greenhouse gases are good, but too much is bad!!)

  • Infrared light’s fave food is CO2

    • CO2 keeps our planet warm by absorbing CO2 radiation and keeps heat trapped in atmosphere

    • W/o greenhouse effect, earth would be 33C cooler

    • TOO MUCH CO2 means heat budget is out of balance and causes global warming

    • Aerosols, fossil fuels, radiation CANT ESCAPE

Local Temp variations

  • Temp varies from place to place because sun heats earths surface unequally (earth tilted at an axis)

    • Actual intensity varies because of TIME OF DAY, CLOUDS, LATITUDE, and SEASON

  • Material and insolation absorption - Black body radiation (dark material absorbs more heat, i.e. hotter in black clothes and dark pavement is hotter than grass)

Factors that reduce amt of solar energy that reaches the surface

  • Angle of sun’s rays hitting surface

    • Lower angle, lower direct energy

  • As sun’s energy travels to earth, its either absorbed, scattered, or reflected

4 Reasons that affect intensity of insolation w/ respect to angle

  1. Time of Day - suns rays vertical at noon, when intensity of insolation is greatest,

    • warmest time is later in the day because lower atmosphere receives more heat from the ground than it loses. ground temps keep rising into the afternoon

  2. Latitude - 90 degrees North and South

    • Equator has vertical rays all year long. near the poles, sun rays hit surface at low angles. MI has variety of seasons because we’re a mid-lat state

  3. Cloud Cover - intensity of sun can depend on cloud cover

    • Clouds absorb, reflect, and scatter rays back into space. more solar energy reaches earth on clear days. At night, more radiation that soaked into ground during the day travels back into space better on clear nights rather than cloudy nights.

  4. Seasons/Time of year

    • mid-lat states get NEAR vertical rays in summer so temp is hot. less vertical rays in winter so temps are cooler. July is warmest month it takes about a month to have the ground consistently heat up to max and stay that way!

    • Weakest amount of sun - December 21 (shortest day)

    • Most amount of sun - June 21 (longest day)


Heating of water and land

  • sunny summer day → sand is warmer than ocean water

  • nighttime → sand cools faster than water

    • Continents do the same thing

3 Reasons temp of land varies more than temp of water

  1. Heat from sun spreads thru a greater depth in water and only heats the top few centimeters on land. Land is heated up quicker bc heat is not spread out as much as water

  2. In water, some solar energy is used in evaporation so less energy can heat water

  3. Water needs more energy than land to raise temp.

    • Specific Heat - amt of heat needed to raise 1 gram of a substance 1C.

    • Water specific heat is 3x that of land, higher the heat the slower the temp change

La Nina

  • Harsh winters and summers

La Nino

  • Chill Winters and summers

Air pollutants - any airborne gas that can harm people or environment

  • NATURAL AIR POLLUTANTS (N.A.P.s): Vols, forest fires

  • HUMAN ACTIVITY POLLUTANTS (H.A.P.s):

    • Carbon monoxide (car exhaust)

    • nitrogen dioxide (burning fossil fuels)

    • sulfur dioxide (fossil fuels)

    • particulate matter (dust, smoke, soot, ash)

    • Lead (battery plants and smelters)

    • Ozone (reaction w/ nitrogen oxides and hydrocarbon in presence of sunlight)

Good + Bad ozone

  • Good in stratosphere, protects from UV rays and produced naturally over mills of years

  • Bad in Troposphere, urban city smog made by humans/cars, harmful to breathe and kills vegetation and trees