Flashcards in Aerosol forcing Deck (52)
What is radiative forcing?
The change in net irradiance at the tropopause with surface and tropospheric temperatures held fixed (positive values imply a heating of the troposphere)
How will CO2 change in the future?
Considerable uncertainty, don't know how it will evolve in the future
What is an aerosol?
Suspension of tiny particles in the air, with a diameter between 0.01-10 micrometers
What makes up aerosols?
Sulfates, nitrates, organic compounds, metals, dust, sea salt ...
Where do aerosols come from?
How many people does EU legislation on aerosols save per year?
How much soot is produced from biomass burning per year?
How much industrial dust is emitted every year?
How much anthropogenic sulphate is emitted each year?
How much biogenic volatile organic carbon (VOC) is emitted every year?
Where are aerosols generated?
-natural: forest fires, dust etc.
-overall, anywhere outside of the poles, aerosol is being generated
Which two ways can be classify aerosols?
Primary and Secondary
What is a primary aerosol?
An aerosol that is directly emitted to the atmosphere e.g. sea salt
What is a secondary aerosol?
Originate from gases which then oxidise or nucleate to form the secondary aerosol (important for cloud formation)
What does volatile mean?
Easily evaporated (less volatile means something is more likely to condense)
What two ways are aerosols removed?
Dry and wet processes
How does lifetime of aerosols change if they reach the stratosphere?
Longer life time e.g. after volcanic eruptions, can remain for a few years
What is aerosol mass important for?
What is aerosol number important for?
Effect on clouds (CCN)
How does aerosol mass differ?
Bulk concentration near emission source
How does aerosol number differ?
Homogenised, reasonable spread (secondary aerosols are able to form further away from source)
What is the annual mean mass of PM2.5?
1-100 µg m-3
What is the annual mean surface particle number?
100-10,000 particles m-3
What model predicts annual mean surface particle number?
GLOMAP global aerosol model
What satellites predicts annual mean mass of PM2.5?
Where does anthropogenic sulphate originate from?
Burning fossil fuels, Volcanoes and Phytoplankton
How does burning fossil fuels generate sulphate aerosol?
SO2 and CO2 oxidises to Sulphuric acid (H2SO4) which nucleated and condenses to Sulfate aerosol
What is one direct aerosol effect?
Scattering and absorption of solar radiation
What is one indirect aerosol effect?
Changes in cloud properties