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The Effect of Aerosols on the Climate

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Title: The Effect of Aerosols on the Climate


1
The Effect of Aerosols on the Climate
  • By
  • Hugh Alvarado
  • Student Researchers Juan Rodrigez, Irving
    Andino, Johan Toloza
  • Faculty Mentors Dr. James Frost1, Dr. Elizabeth
    Rudolph2, and
  • Mr. Ryan Hutchinson3   
  • 1LaGuardia Community College 31-10 Thomson
    Avenue, Long Island City, New York 11101  
  • 2City College New York, New York  
  • 3Medgar Evers College 1150 Carroll Street,
    Brooklyn, NY 11225  
  • of the City University of New York

2
Abstract
  • Aerosols in our atmosphere can affect our climate
    both directly and indirectly.
  • The direct effect can cause climate forcing by
    absorbing and reflecting sunlight, therefore,
    cooling the atmosphere. While the indirect
    effect modifies cloud properties.
  • With the help of the handheld Polarimeter in
    conjunction  with the automated CIMEL sun
    photometer, we can effectively determine the
    optical depth and size of aerosol particles. 

3
Introduction
  • What are Aerosols?
  • Aerosols are tiny solid or liquid particles
    suspended in the air. These are often seen by the
    naked eye as smoke, haze and dust. Some occur
    naturally, originating from volcanoes, dust
    storms, forest and grassland fires, living
    vegetation, and sea spray.
  • However, a greater percentage of aerosol
    particles originate from Human activities, such
    as the burning of fossil fuels and the alteration
    of the natural surface cover.

4
Aerosols Properties
  • However, the problem with aerosols is that they
    have a great variety of properties, which makes
    them difficult to identify, locate, and classify.
  • Aerosols divide into, Troposheric and
    Stratospheric aerosols.
  • Aerosols differ in size, chemical composition,
    and lifetime.

5
Types of Aerosols
  • Troposperic Aerosols
  • Aerosols located in the troposphere, these are
    mainly anthropogenic.
  • This type of aerosol varies in size and chemical
    composition, according to the region where it is
    located.
  • Have a direct effect on the climate.
  • Stratospheric Aerosol
  • Aerosols located in the higher zone of the lower
    atmosphere.
  • This type of aerosols affect the properties of
    clouds.
  • Have an indirect effect on the climate.

6
Climatic Effect of Aerosols(Problem)
7
Tropospheric and Stratospheric Aerosols
8
Methodology
  • In this project we used a Hand-Held Polarimeter
    to measure the refractive index, optical depth,
    and particle size (radius) of aerosols. To test
    the accuracy of our data, we compared the data
    obtained from the Polarimeter, with data obtained
    from a CIMEL sun photometer.
  • The data is collected by aiming the Polarimeter
    toward the sun at different angles. At the same
    time, we rotated the Polarimeter to determine the
    Imax and Imin values. Finally, we analyzed the
    data obtained using IDL (computer program) to
    determine the optical depth and size of the
    particles.

9
Polarimeter
10
Results
  • Data
  • Comparison of data taken at the same place on
    different days (and under varying weather
    conditions). These charts represent the values
    for the data acquired on July 11, 2005 and July
    12, 2005.
  • Blue color filter used
  • 05_07_12 clear
  • Angle    Imax   Imin
  • 30        165     152
  • 40        144     118
  • 50        125      90
  • 60        111      73
  • 70        105      60
  • 80        106      55
  • 90        119      61
  • 05_07_11  cloudy
  • Angle    Imax   Imin
  • 30        161     153
  • 40        115     105
  • 50        92       73
  • 60        79       73
  • 70        72       42
  • 80        72       36
  • 90        89       61

11
Data
  • After analyzing the data obtained from both days,
    we discovered that the aerosol particles from
    July 12, 2005, have greater radii and optical
    depth than the particles from July 11, 2005.

12
Discussion
  • Although ideally we would be able to clear the
    atmosphere of harmful aerosols, such an option is
    unavailable.
  • However, there are solutions to depress the
    presence of aerosols in the atmosphere. Laws can
    be enacted by the major industrial countries
    around the world to limit aerosol ejection by
    reducing the use of fuels, energy, and the
    production of waste. Implementing laws that
    regulate the use of raw materials and require the
    use of renewable resources will give scientist
    more time to analyze aerosols and develop methods
    to clear them from our atmosphere before aerosols
    reach dangerously high levels.

13
Conclusion
  • After analyzing the data collected with the
    Polarimeter, we can concur that aerosols can
    change in size and optical depth in a matter of
    hours if not seconds. Similarly, we hypothesized
    that aerosols modify the properties of clouds. By
    comparing the amount of energy measured on July
    11th with the measurements taken on July 12th ,
    we concluded that less energy reaches the earth
    on cloudy days, than it does on clear days.

14
Future Work
  • To collect data using instruments that analyze
    chemical composition, refractive index, and
    optical depth of aerosols.
  • Investigate the purpose of sulfur in the
    aerosols.
  • Continue gathering data to develop weather
    models.

15
Acknowledgements
  • Dr. Rudolph, Dr. Frost
  • Juan Rodrigez, Irving Andino, Johan Toloza
  • NASA Sharp

16
Bibliography
  • Dr. James Frost. Aerosol Project at La Guardia.
    Online. La Guardia Community College.
    http//www.cis.lagcc.cuny.edu/frost/html/
  • Center for Atmospheric Sciences. Online. NASA and
    NOAA. http//cas.hamptonu.edu/research/topics/5-6a
    ersols.html
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