| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
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| Initial Amendment Date: | July 27, 2016 |
| Latest Amendment Date: | July 27, 2016 |
| Award Number: | 1638307 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Sylvia Edgerton
sedgerto@nsf.gov (703)292-8522 AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | August 1, 2016 |
| End Date: | July 31, 2020 (Estimated) |
| Total Intended Award Amount: | $489,811.00 |
| Total Awarded Amount to Date: | $489,811.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
310 E CAMPUS RD RM 409 ATHENS GA US 30602-1589 (706)542-5939 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
140 Cedar St. Athens GA US 30602-1589 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Atmospheric Chemistry |
| Primary Program Source: |
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| Program Reference Code(s): | |
| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
This project focuses on the development of new instrumentation for measuring the optical properties of atmospheric aerosol. These instruments will provide measurements of light scattering and absorption by aerosols and enable better characterization of soot particles and particles containing black and brown carbon. A better understanding of the optical properties of atmospheric aerosol is needed for more accurate ground-based and satellite retrievals of data on atmospheric aerosols and for developing improved global climate models.
This research will: (1) build a portable 3-wavelength polar nephelometer to measure light scattering by particles as a function of angle and light polarization; (2) expand the capabilities for measuring ambient aerosol absorption by adding a near-IR channel to a photoacoustic spectrophotometer (PAS), building a UV PAS instrument, and constructing a thermodenuder to better measure the black and brown carbon components of absorption, and (3) more accurately measure the optical properties of soot (black and black carbon) and especially those properties associated with aerosol coatings.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The major goals of this project were to develop instruments and tools for better characterizing how aerosol particles absorb and scatter sunlight in the atmosphere. A more complete understanding of these interactions make possible more accurate modeling of the earth's atmospheric system, better satellite retrievals of important atmosperic constituents and predicitons of the effects that various policy decisions have on the atmosphere.
A major accomplishment of this project was the development and characterization of two unique instruments for measuring aerosol absorption directly without the complications arising from collecting particles on filters. These two instruments include seven different wavelengths of light spanning the UV and visible region of the spectrum. This broad spectral capability allows for a more complete measure of aerosol absorption by sunlight.
Another major accomplishment of this project was the construction of a polar nephelometer, which is an instrument to measure how much aerosol particles scatter light in different directions. Such measurements are important because they allow for a more accurate determination of how aerosols impact radiative balance in the atmosphere.
A third instrument to measure aerosol extinction was also built, tested and deployed during this project. This instrument operates over the UV-visible region of the spectrum simultaneously measuring extinction at 200 wavelengths. The wealth of information provided makes it possible to accurately represent the full extinction spectrum from which various particle properties can be inferred.
Over the course of this project, we have used measurements from all three of these types of instruments to more carefully study both atmospheric aerosols and laboratory-generated particles that are important in the atmosphere. For example, we have studied ammonium sulfate particles and have been able to make more accurate measurements of their refractive index, a key parameter needed to accurately model them in atmospheric chemistry and physics models. We have also measure the refractive index of polystyrene latex spheres, manufactured particles that are commonly used to calibrate and validate a host of instruments; our measurements have reduced uncertainty on this important parameter. In addition, we have used our measurements of ambient aerosols to develop a new particle classification system based on machine learning methods, which should aid others attempting to classify particles using both ground-based and satellite-based optical measurements.
Last Modified: 10/02/2020
Modified by: Geoffrey D Smith
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