Satellite measurements of large-scale air pollution: Methods

Journal Article · Wed Jun 20 04:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JD095iD07p09895· OSTI ID:5332439

Kaufman, Y J; Fraser, R S; Ferrare, R A ^[1]

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1. NASA Goddard Space Flight Center, Greenbelt, MD (USA)

A method is presented for simultaneous determination of the aerosol optical thickness ({tau}{sub a}), particle size (r{sub m}, geometric mean mass radius for a lognormal distribution) and the single scattering albedo ({omega}{sub 0}, ratio between scattering and scattering + absorption) from satellite imagery. The method is based on satellite images of the surface (land and water) in the visible and near-IR bands and is applied here to the first two channels of the Advanced Very High Resolution Radiometer (AVHRR) sensor. The aerosol characteristics are obtained from the difference in the upward radiances, detected by the satellite, between a clear and a hazy day. Therefore the method is mainly useful for remote sensing of large-scale air pollution (e.g., smoke from a large fire or concentrated anthropogenic pollution), which introduces dense aerosol into the atmosphere (aerosol optical thickness {ge}0.4) on top of an existing aerosol. The method is very sensitive to the stability of the surface reflectance between the clear day and the hazy day. It also requires accurate satellite calibration (preferably not more than 5% error) and stable calibration with good relative values between the two bands used in the analysis. With these requirements, the aerosol optical thickness can be derived with an error of {Delta}{tau}{sub a} = 0.08-0.15. For an assumed lognormal size distribution, the particle geometrical mean mass radius r{sub m} can be derived (if good calibration is available) with an error of {Delta}r{sub m} = {plus minus}(0.10-0.20){mu}m, and {omega}{sub 0} with {Delta}{omega}{sub 0} = {plus minus}0.03 for {omega}{sub 0} close to 1 and {Delta}{sub omega}{sub 0} = {plus minus}(0.03-0.07) for {omega}{sub 0} about 0.8. The method was applied to AVHRR images of a forest fire smoke.

• OSTI ID: 5332439
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:D7; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
ABSORPTION
AEROSOLS
AIR POLLUTION MONITORING
ALBEDO
CALIBRATION
COLLOIDS
COMPARATIVE EVALUATIONS
DISPERSIONS
EVALUATION
FORESTS
INFRARED SPECTRA
MEASURING INSTRUMENTS
MONITORING
OPACITY
OPTICAL PROPERTIES
PARTICLE SIZE
PERFORMANCE
PHOTOMETERS
PHYSICAL PROPERTIES
RADIATION DETECTORS
RADIOMETERS
REFLECTIVITY
REMOTE SENSING
RESIDUES
SATELLITES
SCATTERING
SIZE
SMOKES
SOLS
SPECTRA
SURFACE PROPERTIES
VISIBLE SPECTRA