Aerosol Direct Radiative Effects over China Based on Long-Term Observations within the Sun–Sky Radiometer Observation Network (SONET)

Abstract

To investigate aerosol radiative effects, the Sun–Sky Radiometer Observation Network (SONET) has performed long-term observations of columnar atmospheric aerosol properties at 20 distributed stations around China. The aerosol direct radiative forcing (RF) and efficiency (RFE, the rate at which the atmosphere is forced per unit of aerosol optical depth) were estimated using radiative transfer model simulations based on the ground-based observations dating back to 2009. Results of multi-year monthly average RF illustrated that: the dust-dominant aerosol population at arid and semi-arid sites exerted moderate cooling effects (−8.0~−31.2 W/m2) at the top and bottom of atmosphere (TOA and BOA); RF at continental background site was very weak (−0.8~−2.9 W/m2); fine-mode dominant aerosols at urban and suburban sites exerted moderate cooling effects (−9.3~−24.1 W/m2) at TOA but more significant cooling effects (−19.4~−50.6 W/m2) at BOA; RF at coastal sites was comparable with values of urban sites (−5.5~−19.5 W/m2 at TOA, and −15.6~−44.6 W/m2 at BOA), owing to combined influences by marine and urban–industrial aerosols. Differences between RFE at TOA and BOA indicated that coarse-mode dominant aerosols at arid, semi-arid, and continental background sites were less efficient to warm the atmosphere; but fine-mode dominant aerosols at urban, suburban, and coastal sites were shown to be more efficient to heat the atmosphere.

Strong Aerosol Absorption and Its Radiative Effects in Lhasa on the Tibetan Plateau

“…The flowrates were set at 1.3 and 3 L min −1 for CEA and AE33, respectively. To get the absorption coefficient correction factor measured by AE33 due to multiple scattering, aerosol absorption at λ = 532 nm determined by CEA was used as the reference (Li, Li, et al., 2020; Li, Xiao, et al., 2020). Since multiple scattering correction factor is wavelength‐independent (Saleh et al., 2014; Zhao et al., 2020), the correction factor (2.62 for this study, Figure S2 in Supporting Information ) could be also used for other wavelengths to obtain reasonable aerosol absorptions.…”

“…Remote sensing observations showed that aerosol optical depth (AOD) in TP could be 10 times lower compared with sites in eastern China (de Leeuw et al., 2018; Li, Li, et al., 2020; Li, Xiao, et al., 2020; Lu et al., 2022). Previous studies evaluated that aerosol over TP had weak impact on radiative forcing based on ground based remote sensing observation, as it was less efficient to warm the atmosphere due to the low aerosol loading (Li, Li, et al., 2020; Li, Xiao, et al., 2020). However, aerosol radiative effects over TP still have large uncertainties because of inaccurate knowledge of aerosol optical properties, especially SSA.…”

Combined Characterization of Airborne Saharan Dust above Sofia, Bulgaria, during Blocking-Pattern Conditioned Dust Episode in February 2021

“…The LIRIC-2 code [115] is an evolution of LIRIC. Also, it includes new program modules for processing data of LRS measurements when Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) of NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite measures aerosols in the vicinity of AERONET or Sun-sky radiometer Observation NETwork (SONET) [116,117] radiometric site. New program shell and modules were developed to ensure the implementation of new options for the formation and preliminary processing of input data files and to estimate the uncertainty of the retrieved aerosol parameters for the specified input data uncertainty.…”

Aerosols over East and South Asia: Type Identification, Optical Properties, and Implications for Radiative Forcing

“…Aerosol composition, concentration, and optical and physical properties are important in constraining the radiative effect of aerosols [29][30][31][32][33][34]. For example, Déandreis used a chemistry-aerosol model and found that the sulfate aerosol direct radiative effect increases almost linearly as the aerosol concentration increases [29].…”

“…For example, Déandreis used a chemistry-aerosol model and found that the sulfate aerosol direct radiative effect increases almost linearly as the aerosol concentration increases [29]. The aerosol radiative forcing at the bottom and the top of the atmosphere over China were obtained based on the long-term observations within SONET [30]. It is determined that the aerosol radiative forcing at the top of the atmosphere and the surface both doubled during an aerosol event with a peak AOD of 0.6 in Central Europe [31].…”