Global Atmospheric Change Flashcards
Ozone formation in stratosphere
- occurs continuously
* oxygen & sunlight
2 major global scale environmental issues of international concern
1) global stratospheric ozone reduction
2) global climate change
Ozone depletion in stratosphere
*release of source gases
-halocarbons (chlorofluorocarbons [CFCs], halons)
-natural sources (methyl chloride CH3Cl, methyl bromide
CH3Br)
*source gases are ultimately converted by UV radiation to reactive halogen gases, which destroy ozone
The Antarctic Ozone Hole
Ozone hole forms because of the cold temperature of the Antarctic stratosphere
Antarctic Ozone Hole results in…
The formation of polar stratospheric clouds (PSC) aka ice clouds
Polar stratospheric clouds do what?
1) Convert inactive forms of chlorine (HCl & ClONO2) to chlorine gases
2) when sunlight becomes available (September, spring) the chlorine gas is converted to a reactive form of chlorine, which destroys ozone
3) causes seasonal ozone depletion
Arctic depletion?
Depletion occurs but less severe, no large/ recurrent ozone hole
Why is depletion less severe in the Arctic?
The arctic stratospheric winter is generally warmer which reduces the likelihood of PSC formation
Trophospheric O3
Criteria pollutant
Stratospheric O3
Ozone layer
Climate change drivers (3) and what they may be affected by
1) changing the incoming solar radiation
- changes in Earth’s orbit
- changes in the Sun
2) altering the long wave radiation radiated back to space
- changes in greenhouse gases
3) changing the fractions of solar radiation that is reflected (albedo)
- changes in cloud covers
- changes in aerosols
Orbital variations
Milankovitch cycles
1) eccentricity 2) obliquity 3) precession
Eccentricity
The extent to which the Earth’s orbit around the Sun departs from a perfect circle
Obliquity
Refers to the Earth’s tilt angle with respect to its orbit
Precession
Changes in the precession of the Earth’s axis
*earth does NOT have a perfect spin around its axis, but it wobbles