Intercomparison of photoacoustic and cavity attenuated phase shift instruments: laboratory calibration and field measurements
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Published:2021-10-28
Issue:2
Volume:10
Page:245-255
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ISSN:2193-0864
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Container-title:Geoscientific Instrumentation, Methods and Data Systems
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language:en
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Short-container-title:Geosci. Instrum. Method. Data Syst.
Author:
Zhang Jialuo, Chen JunORCID, Wang MengORCID, Su Mingxu, Zhou Wu, Varma Ravi, Lou ShengrongORCID
Abstract
Abstract. The study of aerosol optical properties is essential to
understand its impact on the global climate. In our recent field measurement
carried out in the Gehu area of southwest Changzhou City, a photoacoustic
extinctiometer (PAX) and a cavity attenuated phase shift albedo monitor
(CAPS-ALB) were used for online aerosol optical properties measurement.
Laboratory calibration with gas and particle samples were carried out to
correct disagreements of field measurements. During particle calibration, we
adopted ammonium sulfate (AS) samples for scattering calibration of
nephelometer parts of both the instruments, then combined these with number-size
distribution measurements in the MIE model for calculating the value of the
total scattering (extinction) coefficient. During gas calibration, we
employed high concentrations of NO2 for absorption calibration of the PAX resonator and then further intercompared the extinction coefficient of CAPS-ALB with a cavity-enhanced spectrometer. The correction coefficient obtained
from the laboratory calibration experiments was employed on the optical
properties observed in the field measurements correspondingly and showed
good results in comparison with reconstructed extinction from the IMPROVE
model. The intercomparison of the calibrated optical properties of PAX and
CAPS-ALB in field measurements was in good agreement with slopes of 1.052,
1.024 and 1.046 for extinction, scattering and absorption respectively,
which shows the reliability of measurement results and verifies the
correlation between the photoacoustic and the cavity attenuated phase shift
instruments.
Funder
National Natural Science Foundation of China Ministry of Science and Technology of the People's Republic of China State Key Laboratory of Loess and Quaternary Geology
Publisher
Copernicus GmbH
Subject
Atmospheric Science,Geology,Oceanography
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