Attenuation of Visible Sunlight by Limited Visibility and Cloudiness

EPA Grant Number: CR830890C005
Subproject: this is subproject number R830890C005 , established and managed by the Center Director under grant CR830890
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Center for Environmental Science
Center Director: Frederick, John
Title: Attenuation of Visible Sunlight by Limited Visibility and Cloudiness
Investigators: Frederick, John , Gaffney, Jeffrey S. , Jacobsen, Eric , Marley, Nancy A.
Institution: University of Chicago
EPA Project Officer: Chung, Serena
Project Period: July 1, 2003 through June 30, 2004 (Extended to June 30, 2006)
RFA: Targeted Research Center (2004) Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research

Objective:

A Multi-Filter Rotating Shadowband Radiometer (MFRSR) operated from the roof of the Hinds Geophysical Sciences Building on the University of Chicago campus for much of calendar year 2005. The measurements analyzed here are total (direct plus diffuse) solar irradiances incident on a horizontal surface in five narrow wavelength bands extending from λ = 416 nm to 868 nm, covering the visible portion of the spectrum and a small segment of the near-infrared. Interpretation of the datasets provides a comprehensive description of the roles of cloudiness and limited visibility on solar irradiance reaching the ground. Issues of particular interest center on (1) characterizing the attenuation associated with limited horizontal visibility under clear skies; (2) determining the extent to which measures of cloud cover that are widely available in meteorological datasets constrain the attenuation provided by prevailing cloudiness; (3) identifying situations where fractional cloudiness leads to surface irradiances in excess of the values for clear skies; and (4) identifying any wavelength dependence associated with the attenuation provided by cloudy skies.

Supplemental Keywords:

cloudiness, solar radiation, visibility, attenuation of solar radiation,, RFA, Health, Scientific Discipline, Air, particulate matter, Health Risk Assessment, Risk Assessments, Biochemistry, Ecology and Ecosystems, Engineering, Chemistry, & Physics, particulates, human health effects, PM 2.5, ozone, airborne particulate matter, cardiovascular vulnerability, air pollution, human exposure, ultaviolet illumination, urban air , solar irradiance, human health risk, air quality

Progress and Final Reports:

  • 2004
  • 2005
  • Final Report

  • Main Center Abstract and Reports:

    CR830890    Center for Environmental Science

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    CR830890C001 The Urban Measurements Project—The Urban Atmosphere Observatory
    CR830890C002 The Urban Data Analysis and Modeling Project
    CR830890C003 Attenuation of Ultraviolet Solar Radiation by Cloudy Skies: Links to Urban Air Quality
    CR830890C004 Measurements of Black Carbon in Chicago: Implications for Controls on Diesel Emissions
    CR830890C005 Attenuation of Visible Sunlight by Limited Visibility and Cloudiness
    CR830890C006 The Energy Balance of Urban Microclimates