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Title: Aerosol Single-Scattering Albedo and Asymmetry Parameter from MFRSR Observations during the ARM Aerosol IOP 2003

Abstract

Multi-filter Rotating Shadowband Radiometers (MFRSRs) provide routine measurements of the aerosol optical depth ( << OLE Object: Microsoft Equation 3.0 >> ) at six wavelengths (0.415, 0.5, 0.615, 0.673, 0.870 and 0.94  << OLE Object: Picture (Metafile) >> ). The single-scattering albedo ( << OLE Object: Microsoft Equation 3.0 >> ) is typically estimated from the MFRSR measurements by assuming the asymmetry parameter ( << OLE Object: Microsoft Equation 3.0 >> ). In most instances, however, it is not easy to set an appropriate value of << OLE Object: Microsoft Equation 3.0 >> due to its strong temporal and spatial variability. Here, we introduce and validate an updated version of our retrieval technique that allows one to estimate simultaneously << OLE Object: Microsoft Equation 3.0 >> and << OLE Object: Microsoft Equation 3.0 >> for different types of aerosol. We use the aerosol and radiative properties obtained during the Atmospheric Science Program (ARM) Aerosol Intensive Operational Period (IOP) to validate our retrieval in two ways. First, the MFRSR-retrieved optical properties are compared with those obtained from independent surface, Aerosol Robotic Network (AERONET) and aircraft measurements. The MFRSR-retrieved optical properties are in reasonable agreement with these independent measurements. Second, we performmore » radiative closure experiments using the MFRSR-retrieved optical properties. The calculated broadband values of the direct and diffuse fluxes are comparable (~ 5 << OLE Object: Microsoft Equation 3.0 >> ) to those obtained from measurements.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
910257
Report Number(s):
PNNL-SA-52291
KP1201030; TRN: US200723%%388
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Atmospheric Chemistry and Physics, 7(12):3341-3351; Journal Volume: 7; Journal Issue: 12
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; AEROSOLS; AIRCRAFT; ALBEDO; ASYMMETRY; OPTICAL PROPERTIES; RADIOMETERS; WAVELENGTHS; ATMOSPHERIC CHEMISTRY

Citation Formats

Kassianov, Evgueni I., Flynn, Connor J., Ackerman, Thomas P., and Barnard, James C.. Aerosol Single-Scattering Albedo and Asymmetry Parameter from MFRSR Observations during the ARM Aerosol IOP 2003. United States: N. p., 2007. Web. doi:10.5194/acp-7-3341-2007.
Kassianov, Evgueni I., Flynn, Connor J., Ackerman, Thomas P., & Barnard, James C.. Aerosol Single-Scattering Albedo and Asymmetry Parameter from MFRSR Observations during the ARM Aerosol IOP 2003. United States. doi:10.5194/acp-7-3341-2007.
Kassianov, Evgueni I., Flynn, Connor J., Ackerman, Thomas P., and Barnard, James C.. Fri . "Aerosol Single-Scattering Albedo and Asymmetry Parameter from MFRSR Observations during the ARM Aerosol IOP 2003". United States. doi:10.5194/acp-7-3341-2007.
@article{osti_910257,
title = {Aerosol Single-Scattering Albedo and Asymmetry Parameter from MFRSR Observations during the ARM Aerosol IOP 2003},
author = {Kassianov, Evgueni I. and Flynn, Connor J. and Ackerman, Thomas P. and Barnard, James C.},
abstractNote = {Multi-filter Rotating Shadowband Radiometers (MFRSRs) provide routine measurements of the aerosol optical depth ( << OLE Object: Microsoft Equation 3.0 >> ) at six wavelengths (0.415, 0.5, 0.615, 0.673, 0.870 and 0.94  << OLE Object: Picture (Metafile) >> ). The single-scattering albedo ( << OLE Object: Microsoft Equation 3.0 >> ) is typically estimated from the MFRSR measurements by assuming the asymmetry parameter ( << OLE Object: Microsoft Equation 3.0 >> ). In most instances, however, it is not easy to set an appropriate value of << OLE Object: Microsoft Equation 3.0 >> due to its strong temporal and spatial variability. Here, we introduce and validate an updated version of our retrieval technique that allows one to estimate simultaneously << OLE Object: Microsoft Equation 3.0 >> and << OLE Object: Microsoft Equation 3.0 >> for different types of aerosol. We use the aerosol and radiative properties obtained during the Atmospheric Science Program (ARM) Aerosol Intensive Operational Period (IOP) to validate our retrieval in two ways. First, the MFRSR-retrieved optical properties are compared with those obtained from independent surface, Aerosol Robotic Network (AERONET) and aircraft measurements. The MFRSR-retrieved optical properties are in reasonable agreement with these independent measurements. Second, we perform radiative closure experiments using the MFRSR-retrieved optical properties. The calculated broadband values of the direct and diffuse fluxes are comparable (~ 5 << OLE Object: Microsoft Equation 3.0 >> ) to those obtained from measurements.},
doi = {10.5194/acp-7-3341-2007},
journal = {Atmospheric Chemistry and Physics, 7(12):3341-3351},
number = 12,
volume = 7,
place = {United States},
year = {Fri Jun 15 00:00:00 EDT 2007},
month = {Fri Jun 15 00:00:00 EDT 2007}
}
  • Cited by 3
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  • Multi-filter Rotating Shadowband Radiometers (MFRSRs) are widely deployed over the world. These radiometers measure the total, direct, and diffuse components of shortwave, narrowband irradiance at 6 wavelengths. For 5 of these wavelengths, aerosol optical depths and single scattering albedos can be retrieved. We describe here a simple retrieval technique that can significantly extend the capability of the MFRSR to study atmospheric aerosols and can provide a means for simultaneous retrieval of the aerosol size distribution (for an assumed shape) and the imaginary refractive index. This technique is based on measurements of the direct irradiances at two wavelengths (0.415 μm andmore » 0.870 μm) and the diffuse irradiance at 0.415 μm. Our technique requires assumptions regarding the shape of the aerosol size distribution, and the real part of the refractive index, as well as an estimate of the surface albedo at 0.415 μm. Given plausible values of these quantities, sensitivity tests show that successful retrievals of aerosol characteristics can be achieved. The technique has been applied to derive time series of aerosol microphysical properties from MFRSR measurements taken during a single day, April 27, 2003, of the Mexico City Metropolitan Area field campaign. Additionally, MFRSR-derived aerosol properties are in good agreement with AERONET retrievals made also in Mexico City.« less
  • The aerosol Single Scattering Albedo (SSA) over the global oceans is evaluated based on polarimetric measurements by the PARASOL satellite. The retrieved values for SSA and Aerosol Optical Depth (AOD) agree well with the ground-based measurements of the AErosol RObotic NETwork (AERONET). The global coverage provided by the PARASOL observations represents a unique opportunity to evaluate SSA and AOD simulated by atmospheric transport model runs, as performed in the AeroCom framework. The SSA estimate provided by the AeroCom models is generally higher than the SSA retrieved from both PARASOL and AERONET. On the other hand, the mean simulated AOD ismore » about right or slightly underestimated compared with observations. An overestimate of the SSA by the models would suggest that these simulate an overly strong aerosol radiative cooling at top-of-atmosphere (TOA) and underestimate it at surface. This implies that aerosols have a potential stronger impact within the atmosphere than currently simulated.« less