Retrievals and uncertainty analysis of aerosol single scattering albedo from MFRSR measurements. (January 2015)

• Record Type: Journal Article
• Authors: Yin, Bangsheng; Min, Qilong; Joseph, Everette
• Is Part Of: Journal of quantitative spectroscopy & radiative transfer. Volume 150(2014:Dec.)
• Page Start: 95
• Page End: 106
• Publication Date: 2015-01
• Subjects: MFRSR -- Single scattering albedo -- Diffuse-direct ratio -- Aerosol optical depth -- Angstrom coefficient; Spectrum analysis -- Periodicals; Radiation -- Periodicals; Analyse spectrale -- Périodiques; Rayonnement -- Périodiques; Radiation; Spectrum analysis; Periodicals; 543.0858
• DOI: 10.1016/j.jqsrt.2014.08.012
• Languages: English
• ISSNs: 0022-4073

Abstract

Abstract: Aerosol single scattering albedo (SSA) can be retrieved from the ratio of diffuse horizontal and direct normal fluxes measured from multifilter rotating shadowband radiometer (MFRSR). In this study, the measurement channels at 415 nm and 870 nm are selected for aerosol optical depth (AOD) and Angstrom coefficient retrievals, and the measurements at 415 nm are used for aerosol SSA retrievals with the constraint of retrieved Angstrom coefficient. We extensively assessed various issues impacting on the accuracy of SSA retrieval from measurements to input parameters and assumptions. For cloud-free days with mean aerosol loading of 0.13–0.60, our sensitivity study indicated that: (1) 1% calibration uncertainty can result in 0.8–3.7% changes in retrieved SSA; (2) without considering the cosine respond correction and/or forward scattering correction will result in underestimation of 1.1–3.3% and/or 0.73% in retrieved SSA; (3) an overestimation of 0.1 in asymmetry factor can result in an underestimation of 2.54–3.4% in retrieved SSA; (4) for small aerosol loading (e.g., 0.13), the uncertainty associated with the choice of Rayleigh optical depth value can result in non-negligible change in retrieved SSA (e.g., 0.015); (5) an uncertainty of 0.05 for surface albedo can result in changes of 1.49–5.4% in retrieved SSA. We applied the retrieval algorithm to the MFRSR measurements at the Atmospheric Radiation Measurements (ARM) Southern Great Plains (SGP) site. The retrieved results of AOD, Angstrom coefficient, and SSA are basically consistent with other independent measurements from co-located instruments at the site. Highlights: Aerosol SSA is derived from MFRSR measured diffuse to direct normal irradiance ratio. We extensively assessed various issues impacting on the accuracy of SSA retrieval. The issues are mainly from measurements and model input parameters and assumptions. We applied the retrieval algorithm to the MFRSR measurements at ARM SGP site. The retrieved results are compared with measurements from other instruments at SGP.