Correcting Black Carbon Absorption Measurements with Micro-aethalometer Model 200: Insights from Comparative Analysis

【摘要】 Black carbon（BC） is the strongest visible-light-absorbing aerosol component in the atmosphere, with a significant impact on Earth’s radiative budget. Accurate measurement of BC light absorption is crucial for estimating its radiative effect. The micro-aethalometer model 200（MA200） by AethLabs, USA, offers high-time-resolution measurement of the multi-wavelength absorption coefficient(σ_ab) within 1 s, making it widely used in aerial measurement due to its compact size and light weight. However, the reliability of the measured σ_abhas not been extensively studied in previous research. In this study, we evaluate the performance of MA200 by comparing σ_abmeasurements obtained from MA200 with those from the aethalometer model 33（AE33） by Magee, USA. Our results revealed a significant variation in the determinant coefficient（R²） between σ_abmeasurements from MA200 and AE33, depending on the time resolution. The R² increases from 0.1 to 0.5 and further to 0.97 as the time resolution of σ_abincreases from 1 s to 30 s and 60 s, respectively.We recommend a minimum time resolution of 30 s for stable σ_abmeasurements using MA200. Moreover, we determine σ_ab from attenuation coefficient(σ_ATN) measured by MA200 as σ_ab=(σ_ATN– σ₀)/C_MA, where σ₀ ranges from – 15.3 Mm^–1to– 6.4 Mm^–1and C_MAranges from 2.65 to 3.21. Correcting the measured σ_abbased on the findings of this study can provide reliable results for estimating the radiative effects of BC.更多还原

【Abstract】 Black carbon（BC） is the strongest visible-light-absorbing aerosol component in the atmosphere, with a significant impact on Earth’s radiative budget. Accurate measurement of BC light absorption is crucial for estimating its radiative effect. The micro-aethalometer model 200（MA200） by AethLabs, USA, offers high-time-resolution measurement of the multi-wavelength absorption coefficient(σ_ab) within 1 s, making it widely used in aerial measurement due to its compact size and light weight. However, the reliability of the measured σ_abhas not been extensively studied in previous research. In this study, we evaluate the performance of MA200 by comparing σ_abmeasurements obtained from MA200 with those from the aethalometer model 33（AE33） by Magee, USA. Our results revealed a significant variation in the determinant coefficient（R²） between σ_abmeasurements from MA200 and AE33, depending on the time resolution. The R² increases from 0.1 to 0.5 and further to 0.97 as the time resolution of σ_abincreases from 1 s to 30 s and 60 s, respectively.We recommend a minimum time resolution of 30 s for stable σ_abmeasurements using MA200. Moreover, we determine σ_ab from attenuation coefficient(σ_ATN) measured by MA200 as σ_ab=(σ_ATN– σ₀)/C_MA, where σ₀ ranges from – 15.3 Mm^–1to– 6.4 Mm^–1and C_MAranges from 2.65 to 3.21. Correcting the measured σ_abbased on the findings of this study can provide reliable results for estimating the radiative effects of BC.更多还原