Atmosphere

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  • Created by: catehrine
  • Created on: 16-04-20 11:04

Troposphere

The most unstable and therefore there is weather

18 degrees up to 10km with the temperature decreasing as altitude increases

A the poles it is 9km thick but 17km at the equator due to the hea expansion

Only layer with oxygen for life

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Stratosphere

Temperature increases as altitude increases as the UV is absorbed by the ozone layer

Low air density 

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Mesosphere

Temperature decreases as altitude increases

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Thermosphere

Temperature increases as altitude increases, as the distance from the sun is decreasing and the air is not protected by the ozone layer.

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Greenhouse gases 1

Water Vapour:

  • rayleigh scattering
  • short atmospheric lifetime
  • feedback rather than a forcing
  • warming atmosphere = more water vapour can be held

Methane:

  • less than 40% is natural
  • short residence time
  • GWP of 21

Carbon Dioxide:

  • Increased by 1/3rd after the industrial revolution
  • most long lived
  • photosynthesis accounts for the seasonal variability
  • used to be 280ppm now around 400ppm
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Greenhouse gases 2

Atmospheric aerosols:

  • volcanoes and anthropogenic
  • darkens clouds so they will absorb more UV

Fluorinated gases:

  • Synthetic
  • GWP up to 23000 times higher than carbon dioxide
  • 50000 years

Ozone:

  • Bad = smog in the troposphere
  • Good = ozone layer in the Stratosphere that absorbed the UV
  • High UV breaks the O3 into O2 and O1 - UV then binds them together again
  • If there is chlorine in the atmosphere then that will bind with the oxygen so there won't be enough to form the Ozone layer
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The Ozone layer

1977 = measured the increase of CFCs in the atmosphere

1979 = the ozone was thinning around the poles

1985 = the hole over Antarctica was found

1989 = the Montreal Protocol was established

2012 = HFCs were limited as we don't know the long term effects

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Hurricanes

Conditions

  • 26.7 degree and deep waters - 5-25 degrees north or south the Equator but not at the equator due to the Coriolis effect
  • strong vertical wind shear and trade winds
  • 74mph = hurricane whereas 39mph = tropical storm

Structure

  • Air descending in the eye and warming and then rising along the eye wall 
  • the bigger the pressure difference the stronger the storm
  • rain bands

Saffir Simpson Scale = 1-5 the measure of wind

Accumulated cyclone energy = more factors that include wind, number and duration 

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Hurricane season 2017

3364 deaths

6 hurricanes category 3 or above

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Predicting hurricanes

In 2017 they predicted 5-9

ENSO was in neutral year so there would be a few (La Nina have above average hurricanes)

Warmer sea temperatures would mean there would be an increase in hurricanes

The track of the hurricane can be predicted to a certain extent a few days before but it is always dependent on local weather

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Belize

Tropical cyclones peakeed in the 1600s in which it was an Ice Age 

There has been decreasing storms in Belize due to the fact the ITCZ is moving northwards

  • Due to aerosol forcing the equator was not getting the maximum amount or heat and therefore the ITCZ began moving southwards

The Hadley cell is expanding due to human forcing

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