Earth's Atmosphere Flashcards

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1
Q

What is weather? What factors can impact the weather?

A
  • The state or condition of the atmosphere at a given place and time
  • Temperature
  • Cloud cover
  • Wind speed/direction
  • Humidity
  • Air pressure
  • Precipitation
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2
Q

What is climate?

A

The average weather over a long period of time

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3
Q

What is meteorology?

A

The study of the atmosphere

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4
Q

What is the first layer of the atmosphere?

A
  • Troposphere
  • Thickest air here
  • Weather occurs
  • Has almost all the water vapor carbon dioxide in atmosphere- some escapes into stratosphere
  • Temp decreases as altitude increases- air heated from below by thermal energy radiating from Earth’s surface
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5
Q

What is the second layer of the atmosphere?

A
  • Stratosphere
  • Ozone located here
  • Temp increases as altitude increases- air heated from above- ozone absorbs radiation from the sun
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6
Q

What is the third layer of the atmosphere?

A
  • Mesosphere
  • Where meteors burn up
  • Temp decrease as altitude increases
  • Coldest layer of atmosphere
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7
Q

What is the fourth layer of the atmosphere?

A
  • Thermosphere
  • Ionosphere located here
  • Auroras happen here
  • Temp increases as altitude increases- nitrogen + oxygen atoms absorb x-rays and ultraviolet radiation
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8
Q

Ozone layer (location, benefit, threat, helping it)

A
  • Stratosphere
  • Ozone- compound composed of 3 oxygen atoms (O3), protects all life by absorbing harmful ultraviolet radiation
  • Threat: chlorofluorocarbons manufactured by humans rise into the stratosphere and attack ozone
  • CFC contents peaked in the 1990s and now declining- international rules were passed limiting/banning products that used CFCs- contents decreasing
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9
Q

Where/what is the ionosphere? What is its benefit?

A
  • Lower region of thermosphere
  • Layer of ions
  • Radio waves can bounce off of it
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10
Q

How does air pressure change as elevation increases?

A

Elevation increases- air pressure decreases

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11
Q

How does the density of the air change as elevation increases?

A

Density of air goes down with higher elevation

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12
Q

What is the chemical makeup of Earth’s atmosphere?

A
Nitrogen: 78.1 %
Oxygen: 20.9 %
Argon: 0.93 %
Carbon Dioxide: 0.04 %
Water Vapor: 0.01 - 4.5 %
Helium, ammonia, neon, methane
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13
Q

What is the composition of Earth’s early atmosphere (after asteroid impacts)?

A
  • No free oxygen
  • Water vapor
  • Nitrogen
  • Carbon dioxide (100-1000 times more than we have today)
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14
Q

What was the chaotic history of Earth’s early atmosphere?

A
  • First atmosphere composed of nebula gases (hydrogen, helium, methane, ammonia) obliterated by asteroid impacts
  • Earth’s gravity too weak to hold in the gases, sun heated gases and they escaped Earth’s gravity
  • Volcanoes created a new atmosphere (outgassing)
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15
Q

What is the evidence that there was a lack of free oxygen in early Earth?

A
  • Pyrite
  • Cyanobacteria
  • Stromatolites
  • Banded iron formations
  • Redbeds
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16
Q

What effects would an oxygen-rich atmosphere have on the Earth?

A
  • Gigantism in certain species (insects)
  • High species diversity
  • Low production of new species
  • Huge fires- oxygen is highly flammable
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17
Q

What effects would a low oxygen content atmosphere have on the Earth?

A
  • Mass extinctions
  • Low species diversity
  • More appearances of new species (nature’s way to find a new way to survive)
  • Dinosaurs
18
Q

What is the source of each major gas in the current atmosphere?

A
  • Argon: radioactive decay
  • Nitrogen, carbon dioxide water vapor, argon: volcanoes
  • Oxygen: separated from carbon dioxide by photosynthesis
19
Q

Why did dinosaurs thrive in a low oxygen content atmosphere?

A
  • Developed an efficient respiratory system involving air sacs to move air through the lungs (like a bellows)
  • Oxygen contents rose- more types of dinos, larger dinos
20
Q

Why did birds thrive in a low oxygen content atmosphere?

A
  • Evolved from dinosaurs
  • Same efficient breathing system as dinosaurs
  • Enabled birds to fly high / far and do hard physical work in thin air
21
Q

Adiabatic cooling

A
  • Air cools as it thins
  • The temperature of an air mass decreases as the air mass rises and expands
  • Air density is lower at higher altitudes- air mass expands/less particles/movement to meet equilibrium
  • Uses energy to expand- cools down
22
Q

Auroras

A
  • Sun emits solar wind- charged particles (protons+electrons)
  • Emitted by surface of sun at speed 1-2 million mph
  • Drawn to Earth’s magnetic fields (poles)
  • Slam into atmosphere, transfer energy to atmospheric atoms
  • Atoms emit visible light in order to return to low energy state
23
Q

Banded iron formation

A
  • Started 2.5-1.7 billion years ago
  • Oxygen combined with dissolved iron in Earth’s oceans to form insoluble iron oxides- formed a thin layer on the ocean floor
  • Oxygen mixed with iron in the oceans, rusted iron collected on the seafloor
24
Q

Chlorofluorocarbon

A
  • Used in refrigerants, aerosol spray, and foam packaging

- Destroy the ozone layer

25
Q

Photosynthesis

A

The process of turning carbon dioxide and water into glucose and oxygen with the help of solar energy

26
Q

Redbed

A
  • Rocks that rust due to oxygenated iron presence (iron oxide) in the second half of Earth’s history
  • Oxidized iron in cement
27
Q

Stromatolite

A
  • Layered bulb-like structures produced by colonies of algae and the sediment that they trap
  • Single celled organisms that produced oxygen (slowly)
  • Most advanced lifeform for 3 billion years
  • Eaten later on by new species
28
Q

Greenhouse gas

A
  • Traps heat in the atmosphere
  • Carbon dioxide
  • Methane
29
Q

Cyanobacteria

A

Tiny organisms that produced oxygen by photosynthesis 3.5 billion years ago (blue-green algae)

30
Q

Fossil fuels

A
  • Remains of plants of animals
  • Come in the form of oil, coal, or natural gas
  • Energy from the sun
  • Result of the decomposition of dead plant and animal matter buried deep in the Earth’s crust
  • Pumped from underground and burned to create energy
31
Q

Where is the most common place to find stromatolites today?

A

Shark Bay in Australia

32
Q

Timeline of oxygen on Earth

A

1) 2.7- 3.5 bya: cyanobacteria in oceans made free oxygen by photosynthesis
2) Stromatolites formed from Cyanobacteria
3) 2.5-1.7 bya: banded iron formations, continued until there was no more iron in the oceans to rust. Oxygen had nowhere to go but into the atmosphere
4) 2 bya: red beds formed when oxygen was released into the atmosphere

33
Q

How and why has the carbon dioxide content level in the atmosphere been changing recently?

A

-Use of fossil fuels
-Releases CO2 into atmosphere
-

34
Q

What is good vs bad ozone?

A

GOOD: occurs naturally, protects us from ultraviolet radiation (causes sunburn, skin cancer, eye cataracts)
BAD: product of air pollution, damages respiratory system

35
Q

Pyrite

A
  • Iron+sulfate (fools gold)
  • Rusts when exposed to oxygen to form oxidized pyrite
  • Shiny before rusting
  • Pyrite in sediments still shiny- no oxygen in Early Earth to oxidize it
36
Q

Limestone

A

When carbon dioxide gets deposited on the ocean floor, it forms as part of limestone (does not dissolve)

37
Q

Why would oxygen contents increase and decrease?

A
  • Rotting vegetation removes oxygen
  • Swampy areas + densely vegetated regions- plant matter may not decay before rapidly buried by more plant matter- allows oxygen levels to rise
  • Mountain building- O2 content falls
38
Q

What happens during periods of mountain building? What is the result?

A
  • Deep carbon rich layers may be brought to the surface and eroded
  • Carbon + oxygen- carbon dioxide
  • Result: oxygen content falls, carbon dioxide content rises
39
Q

Adiabatic lapse rate

A

How rapidly air cools as it rises

1 degree C / 100 meters

40
Q

When did dinosaurs go extinct?

A

65 million years ago

Asteroid impact- ash blocked sunlight for a long time

41
Q

Where does the most dramatic ozone depletion occur every year and why?

A
  • Antarctica
  • Specific chemical reactions that deplete the ozone in the stratosphere over Antarctica require cold temps only found in this region