Two-Column Aerosol Project: Aerosol Light Extinction Measurements Field Campaign Report

Dubey, Manvendra²  Aiken, Allison²  Berg, Larry K.³  Freedman, Andrew⁴  Gorkowski, Kyle² 

[1] Pacific Northwest National Laboratory;Los Alamos National Lab. (LANL), Los Alamos, NM (United States);Pacific Northwest National Lab. (PNNL), Richland, WA (United States);Aerodyne Research, Inc., Billerica, MA (United States)

关键词: Two-Column Aerosol Project;    aerosols;    photoacoustic soot spectrometer;   

DOI  :  10.2172/1315486
RP-ID  :  DOE/SC-ARM--16-047
PID  :  OSTI ID: 1315486

学科分类：环境科学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

We deployed Aerodyne Research Inc.???s first Cavity Attenuated Phase Shift extinction (CAPS PMex) monitor (built by Aerodyne) that measures light extinction by using a visible-light-emitting diode (LED) as a light source, a sample cell incorporating two high-reflectivity mirrors centered at the wavelength of the LED, and a vacuum photodiode detector in Cape Cod in 2012/13 for the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility???s Two-Column Aerosol Project (TCAP). The efficacy of this instrument is based on the fact that aerosols are broadband scatterers and absorbers of light. The input LED is square-wave modulated and passed through the sample cell that distorts it due to exponential decay by aerosol light absorption and scattering; this is measured at the detector. The amount of phase shift of the light at the detector is used to determine the light extinction. This extinction measurement provides an absolute value, requiring no calibration. The goal was to compare the CAPS performance with direct measurements of absorption with ARM???s baseline photoacoustic soot spectrometer (PASS-3) and nephelometer instruments to evaluate its performance.