Earth's atmosphere

The atmosphere of Earth comprises of a layer of gas mixture surrounding Earth, known collectively as air, via variable quantities of suspended aerosols and particulates (causing weather features like clouds, hazes), all retained by Earth's gravity.

collectively: overall as a whole
aerosol: substance enclosed in pressure and released as a fine spray, often by means of a propellant gas

The atmosphere is a protective buffer between Earth's surface and space, shields the surface from most meteoroids and ultraviolet solar radiation, keeps it warm and stop diurnal temperature variation (temperature extremes between day and night) by heat retention (greenhouse effect), redistributes heat and moisture among different regions via air currents, and gives chemical and climate conditions for life to be on Earth.

buffer:
diurnal:

[1] Blue light scatters more than other wavelengths by the gases in the atmosphere, around Earth in visible blue layer at the stratosphere, above troposphere's clouds, from space in ISS at 335 km (208 mi) attitude with moon at visible.

By mole fraction (i.e., by molecules amount), dry air is 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also has variable water vapor amount, ~1% average at sea level and 0.4% on the whole atmosphere.

Earth's early atmosphere has accreted gases from the solar nebula, but the atmosphere changed alot overtime, affected by volcanism, impact events, weathering evolution of life (especilly photoautotrophs), etc. Recently, human also contributed to atmospheric changes (climate change; mainly by deforestation and fossil fuel-related global warming), ozone depletion and acid deposition.

The atmosphere has ~5.15×1018 kg mass, 3 quarters within ~11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere is thinner via rising altitude, without definite boundary between the atmosphere and space.

Atmospheric effects are noticeable in atmospheric spacecraft's reentry at ~120 km (75 mi) attitude. Many layers are distinguished in atmosphere by characteristics (like temperature and composition): troposphere, stratosphere, mesosphere, thermosphere and exosphere. Air composition, temperature and atmospheric pressure vary with altitude. Air suitable for use in photosynthesis by terrestrial plants and respiration of terrestrial animals is found within the troposphere.[3]

Study and processes of Earth's atmosphere is called atmospheric science/aerology, with many subfields (like climatology and atmospheric physics) with pioneers like Léon Teisserenc de Bort and Richard Assmann. Historic atmosphere study is called paleoclimatology.

Climate change feedbacks

Countries by carbon dioxide emissions

Paris Agreemeent

References

Quizzes

Stratification

[1] Generally, air pressure and density decrease by atmosphere's altitude. But by temperature, altitude and may stay constant/increase by altitude in some regions. As the general pattern of the temperature/altitude or lapse rate is constant and measurable by instrumented balloon soundings, the temperature behavior is a useful metric to know atmospheric layers. This atmospheric stratification divides the Earth's atmosphere into 5 main layers (highest to lowest):

Exosphere: 700–10,000 km (435–6,214 mi)
Thermosphere (formally ionosphere): 80–700 km (50–435 mi)
Mesosphere: 50–80 km (31–50 mi)
Stratosphere: 12–50 km (7–31 mi)
Troposphere: 0–12 km (0–7 mi)

(formally the ionosphere)

Mnemonic:

"Exo"sphere means "exit" as the outer layer.

"Thermo"sphere means "heat" as the hottest layer.

"Meso"sphhere means "middle" as the middle layer.

"Strato"sphhere means "layer" as the 2nd layer.

"Tropo"sphhere means "response/change" as the 1st layer.

Exosphere

Exosphere is the outermost layer (it's so tenuous some deem it as part of interplanetary space , not atmosphere), extending the thermopause (AKA "exobase") at the thermosphere's top to a poorly defined boundary with the solar wind and interplanetary medium. The altitude of the exobase varies from about 500 kilometres (310 mi; 1,600,000 ft) to about 1,000 kilometres (620 mi) in times of higher incoming solar radiation.

Thermosphere

Mesosphere

Stratosphere

- Tropopause

Tropopause is between troposphere and stratosphere.

Troposphere

Troposphere . It's where all active weather the Earth gets.

Composition

[1] Earth atmosphere's 3 major parts are nitrogen, oxygen, and argon. Water vapor accounts for the atmosphere's ~0.25% by mass. Water vapor concentration (a greenhouse gas) varies alot from ~10 ppm by mole fraction in coldest of atmosphere's parts as much 5% by mole fraction in hot, humid air masses, and concentrations of other atmospheric gases are ofetn quoted in terms of dry air (without water vapor).[8]: 8 remaining gases are often called trace gases, among other are greenhouse gases, mainly carbon dioxide, methane, nitrous oxide, and ozone. Aside argon, other noble gases, neon, helium, krypton, and xenon are also present. Filtered air are trace amounts of many other chemical compounds. Many natural origin substances may be present in locally and seasonally various tiny amounts as aerosols in an unfiltered air sample, like mineral dust and organic composition, pollen and spores, sea spray, and volcanic ash. Many industrial pollutants also may be present as gases or aerosols (e.g. chlorine; elemental or compounds), fluorine compounds and elemental mercury vapor. Sulfur compounds (like hydrogen sulfide and sulfur dioxide/SO2) may derive from natural sources or from industrial air pollution.

pollutants:

Major air constituents:

Average dry air's molecular weight (used to calculate densities or convert between mole fraction and mass fraction) is ~28.946 or 28.964 g/mol--decreases if the air is humid.

Relative gas concentration stays constant til ~10,000 m (33,000 ft).

Pollutants are Not all air pollutants are greenhouse gases.

CO₂ won't absorb ultraviolet (UV) light--mainly absorbs and IR radiation rather than UV light.

Kármán line

The Kármán line, at 100 km (62 mi) or 1.57% of Earth's radius, is often used as the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi). Several layers can be distinguished in the atmosphere based on characteristics such as temperature and composition, namely the troposphere, stratosphere, mesosphere, thermosphere (formally the ionosphere) and exosphere. Air composition, temperature and atmospheric pressure vary with altitude. Air suitable for use in photosynthesis by terrestrial plants and respiration of terrestrial animals is found within the troposphere.[3]

The study of Earth's atmosphere and its processes is called atmospheric science (aerology), and includes multiple subfields, such as climatology and atmospheric physics. Early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann.[4] The study of historic atmosphere is called paleoclimatology.

History

Climate change feedbacks

In global warming, "feedback" is the way a climate system amplifies/reduces an initial disturbance's effect (e.g. increased greenhouse gas emissions), crucial to tell how much Earth's climate change for some amount of initial forcing.

Countries by carbon dioxide emissions

OECD (Organisation for Economic Co-operation and Development) = an international firm of 38 countries. Founded in 1961, to promote economic growth and development through collaborative policy development and analysis. They're a forum for governments to share experiences, identify best practices, and develop high standards for economic policy.

Most OECD countries carbon emissions have been in decline since 2010.

Paris Agreemeent

The Paris Agreemeent is the convention/protocols/amendments/agreements with the goal to keep the average global temperature rise expected this century to well below 2 degrees Celsius, and as close as possible to 1.5 degrees Celsius above pre-industrial levels, as possible.

References

[1] Wikipedia
- [1.2] Kármán line
- [1.3] Exosphere
- [1.4] Thermosphere
- [1.5] Mesosphere
- [1.6] Stratosphere
- [1.7] Trotosphere
- [1.9] Atmospheric pressure
- [1.10] Climate change feedbacks
- [1.11] Atmospheric circulation
- [1.12] List of countries by carbon dioxide emissions
- [1.13] OECD
- [1.14] Paris Agreement
- [1.15] Carbon cycle
- [1.16]
- [1.17]
[2] Layers of the Atmosphere | Meteorology - YT
[3]
[4]
[5]

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Earth's atmosphere

Stratification

Exosphere

Thermosphere

Mesosphere

Stratosphere

- Tropopause

Troposphere

Composition

Kármán line

History

Climate change feedbacks

Countries by carbon dioxide emissions

Paris Agreemeent

References

Quizzes

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