jie yang's homepage Meterology Condition Have Important Influence On Atmospheric Chemical Processes

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Purpose:

To find the database of UV radiation, cloud data, aerosol and albedo data to explain the influence of meterological condition on photochemical processes in the atmosphere.

General idea:

The atmosphere is undergoning many chemical processes, such as aqueous chemical reaction occuring in water droplet in clouds, photochemical reation caused by strong solar radiation and so on. Considering photochemical processes in the atmosphere, there are many factors can have an improtant influence on it, such as cloud mass, aerosole, albedo etc., one of these things can alter either the intensity of solar insolation or shifting the band of radiation.

Outline

  1. UV data solar energy is the driving force for the photochemical reactions in the atmosphere. UV radiation is the special interval of wavelength of the solar radiation and its wavelength is less than 0.4 micrometer and greater than 0.001 micrometer.
    1. National Ocean and Aeronatutical Adminstration (NOAA)
      1. Integrated Surface Isolation Study (ISIS)
      2. Surface Radiation Budget Monitoring (SURFRAD)
    2. JPL Radiation Effects Database
    3. Solar Radiation and Radiation Balance Data - Publication of "Solar Radiation and Radiation Balance Data" was published by the World Radiation Data Center, St. Petersburg, Russia in cooperation with the WMO. (from 1964)
    4. Other sources

  2. Cloud data
    1. Cloud radiative processes
    2. SAGE II database - Statospheric Aerosol and Gas Experiment II
      Cloud coverage
    3. Clouds and the energy

  3. Aerosole data and its influence on global energy budget
    1. Atmopospheric aerosoles
      Atmospheric aerosoles (sub-micron and micron-sized particles suspended in air) originate both from natural and man-made sources. Due to their short lifetime and strong tropospheric interactions, their global concentrations and properties are poorly known. Aerosol particles affect atmospheric radiation and cloud microphysics, and are considered a major uncertainty in climate forcing.
    2. The global tropospheric aerosol
    3. CART Aerosol Data Center
      This links given here are intended to give a variety sources of aerosol data, including in-situ properties of aerosol,column aerosol properties,vertical profiles of aerosol properties as well as other aerosol links.
    4. SAGE II database for aerosoles

  4. Albedo
    1. Definition
      Albedo is defined as the ratio of amount of solar energy reflected by surface over the total amount of solar energy reaching the surface.
    2. General albedo of different kinds of surface
    3. Matthews Datasets - Documentation for Matthews vegetation, cultivation intensity abd albedo. (Although no data avaliable on line, it provides an address to where you can ask for data)
    4. A satallite albedo map of Canada

A case study

Site: Newfoundland, Canada

Time: Mar 22 - Apr. 30, 1997

Purpose: showing how those data used for examining photochemical processes

  • Day cycle of solar radiation (measured as UV radiation) and cloud effects
  • Influence of albedo on reflection of solar radiation
  • Influence of albedo on rate constant (Jno2) of photochemical dissociation of NO2

    • Conclusion

  • UV radiation is the great engine pushing the photochemical reactions precessing in the atmosphere. Since solar zenith angle is the key factor influencing the intensity of solar radiation, we can examine a clearly day cycle of UV radiation and also a seasonal cycle. And accordingly the highest photochemical dissociation rate constant is recorded at noon and summer.
  • Photochemical rections in the atmosphere is influenced by meterological factors such as cloud, albedo, aerosol. When cloud is present, they can either reduce the radiation by blocking and absorbing the direct sun light or increase radiation by scattering and reflecting undirect lights. The net effect of clouds on energy reached a given point is determinded by the relative magnitude of those opposite processes.
  • Increasing albedo will increace the amount of energy reaching a given point which means enhance the photodissociation rate constant of NO2. Since snow and ice have the highest albedo, meterological conditions favoring snowing is contributing to increasing the photodissociation rate constant of NO2 if other conditions do not change.
  • The major effect of aerosol on radiation distribution is somehow similar to that of clouds. Generally the presence of aerosol will decrease the radiation reaching the surface of the earth. But its effects on photochemical processes in the atmosphere is very complicated. /body>