The Atmosphere Flashcards
origin of UV radiation
nuclear fusion from sun = produces lots of energy (EM radiation). reaction when hydrogen atoms join to produce helium + neutron
2 role of UV radiation
- stimulates vit. D in humans (increases absorption of phosphorus and calcium).
- Plants reflect UV to attract pollinators
in the stratosphere, what happens to UV
UVB (partially) UVC (fully) absorbed by ozone, is converted in chemical energy which is then converted into heat
what happens to UVA
is reflected off of Earths surface
origin of IR radiation
heat absorbed from insolation emitted by Earth’s surface into atmosphere
2 roles of IR
- greenhouse gases absorb IR, converts into heat (greenhouse effect)
- different levels of exposure between surface/deeper water so creates different water temps for different organisms
origin of visible light
insolation from the sun which is reflected from Earth’s surface
2 roles of visible light
- allows for organisms to see
- allows plants to photosynthesise (using it to split H2O)- converted to chem. energy in the products
Anthropogenic sources of CO2 and residence time
- combustion of fossil fuels/wood
- drainage of marshes
+ 100 years
Anthropogenic sources of CH4 and residence time
- paddy fields (rice fields) (anaerobic resp.)
- cattle farming
- landfills (anaerobic resp.)
+ 12 years
Anthropogenic sources of NOx and residence time
combustion of oil/diesel in vehicle engines
+114 years
Anthropogenic sources of tropospheric ozone and residence time
formed when UV reacts with NOx from exhausts/smokestacks
+ 23-28 years
Anthropogenic sources of CFCs and residence time
- aerosols
- fluids for refrigerators
+ 50- several hundred years
definition of residence time
the average time a molecule stays in the atmosphere since leaving it’s source
Match up the relative effects of the gases:
- CO2 = ___
- CH4 = ___
- NOx = ___
- Tropospheric = ___
- CFCs = ___
- 1
- 25
- 160
- 2000
- 25000
what is the role of the Thermohaline circulation in the north atlantic (also known as the North Atlantic Conveyor or the Gulf stream) ?
bring warm water from the Caribbean towards Europe
how does the north atlantic conveyor work?
H2O becomes more dense when cold and so sinks towards the pole. More Saline = more dense
How does the melting of the ice caps affect the north atlantic conveyor?
increases freshwater, so decreases salinity so decreases density, less warm water being deposited. NAC slows/stops
what is El Nino ?
westward wind changes direction. drop in rainfall in Australia. loss of nutrient rich water in south america and also flooding/lots of rainfall.