Determining Aerosol Radiative Properties Using the TSI 3563 Integrating Nephelometer

Abstract

Methods for reducing and quantifying the uncertainties in aerosol optical properties measured with the TSI 3563 integrating nephelometer are presented. For nearly all applications, the recommended calibration gases are air and CO,. By routinely characterizing the instrumental response to these gases, a diagnostic record of instrument performance can be created. This record can be used to improve measurement accuracy and quantify uncertainties due to instrumental noise and calibration drift. When measuring scattering by particles, size segregation upstream of the nephelometer a t about 1 p m aerodynamic diameter greatly increases the information content of the data for two reasons: one stemming from the independence of coarse and fine particles in the atmosphere, and the second stemming from the size dependence of the nephelometer response. For many applications (e.g., extinction budget studies) it is important to correct nephelometer data for the effects of angular nonidealities. Correction factors appropriate to a broad range of sampling conditions are given herein and are shown to be constrained by the wavelength dependence of light scattering, as measured by the nephelometer. Finally, the nephelometer measurement is nondestructive, such that the sampled aerosol can be further analyzed downstream. Data from two nephelometers operated in series are used to evaluate this procedure. A small loss of super-pm particles (5-10%) is found, while the sub-pm data demonstrates measurement reproducibility within k 1%.

Climatological aspects of aerosol optical properties in Northern Greece

“…The operating principles of the TSI nephelometer as well as the methodology used to extract σ sp and σ bsp are extensively described by Andreae et al (2002). Corrections for the angular truncation and the nonlambertian errors were performed using the correction equations proposed by Anderson and Ogren (1998). For σ sp , correction was based on the Angström exponents,å σ , whereas constant correction factors were used for σ bsp .…”

Motivation, rationale and key results from the GERBILS Saharan dust measurement campaign

“…Corrections were made for refractive index by assuming the refractive index of Balkanski et al (2007) with a haematite content of 1.5%, and shape by assuming irregular shaped particles and using combinations of Mie scattering, T-matrix, and ray tracing techniques 3-wavelength nephelometer and particle soot absorption photometer (PSAP), which were corrected for non-ideal scattering (Anderson and Ogren, 1998), and absorption artefacts (Bond et al, 1999). The filter measurement system (Klaver et al, 2011) consists of thin-walled nozzles (Andreae et al, 1998) with curved leading edges leading to two stacked filter units under sub-isokinetic conditions.…”

Changes in visibility with PM2.5 composition and relative humidity at a background site in the Pearl River Delta region

“…The data for wavelength of 525 nm was chosen for discussion in this study. The data were corrected for truncation errors and the non-Lambertian light source following the widely used method (Anderson and Ogren, 1998) where a linear function of the Angstrom exponent å 450/635 was used. We estimated a total nephelometer correction factor of 1.15 ± 0.02 for this study.…”