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ATOC 4720: class 17

ATOC 4720: class 17. Atmospheric aerosols Effects on atmospheric phenomena. Total concentration. Concentration vary with location and time. Generally,. Over the ocean:. Rural land areas:. Polluted air:. >10km, H=7km; <5km, H=3km. Size spectra. <0.2um ;. 0.2-2um; >2um. Similar.

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ATOC 4720: class 17

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  1. ATOC 4720: class 17 • Atmospheric aerosols • Effects on atmospheric phenomena

  2. Total concentration

  3. Concentration vary with location and time. Generally, Over the ocean: Rural land areas: Polluted air: >10km, H=7km; <5km, H=3km.

  4. Size spectra <0.2um; 0.2-2um; >2um Similar

  5. Sources and sinks: Aitken nuclei [1] Combustion processes (human activities, Forest fires, volcanoes, gas-to-particle Conversion;) [2] Large to giant aerosol: wind blown dust, emission of pollens, and spores from plants; Ocean: bursting of Air bubbles (under high windspeed); urban Industrial processes.

  6. Sinks: Aitken nuclei--big aerosols: Precipitation and gravity. Global: Precipitation 80-90%; 10-20%: gravitational settling. Aitken nuclei: <1hour in polluted Air or in clouds; Large: days; Giant: minutes-hours-days. Life time: Level-dependent:

  7. Average Residence Time of Aerosols in Atmosphere

  8. TRANSPORT: Desert Aerosol Transport over North Africa and the Mediterranean. The 2D distribution of aerosols Concentration for the period from August, 1996 to April, 2000 (top panel). Main source regions of the UV-absorbing aerosols can be inferred, and these regions are marked in the bottom panel.

  9. Desert Aerosol Transport over North Africa and the Mediterranean. Largest values Tend to be along The dust plume trajectories

  10. Effects on atmospheric phenomena [1] Clouds and precipitation: Good: Precitaion; bad: acid rain

  11. [2] Electricity: electric field and conductivity; measurements of electricity may indicate aerosol concentration;

  12. nuclei Electric field

  13. [3] Radiation Scattering & absorption of solar radiation: Important for the earth’s radiation budget; Qr at the earth’s surface can cause SST (sea surface temperature) variability, And thus force variability in atmospheric Circulation and convection: affecting Climate.

  14. [4] Chemistry: Liquid aerosol absorbs gases: react; Solid aerosol provide surfaces upon which Gases can be absorbed and react; Aerosol & sulfur dioxide from polluted air accumulate in stable (T-inversion), moist air==sulfur dioxide is converted to sulfates==smog; 1952 Landon smog caused 4000 people death.

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