Journal Article

Spatial Distribution of Aerosol Microphysical and Optical Properties and Direct Radiative Effect from the China Aerosol Remote Sensing Network

Estelles, Victor, Zhao, Hujia, Xia, Xiangao, Yang, Leiku, Che, Huizheng, Wang, Yaqiang, Qi, Bing, Holben, Brent N, Cuevas-Agullo, Emilio, Gong, Wei, Zhang, Renjian, Zhang, Xiaochun, Dubrovnik, Oleg, Yang, Honglong, Zheng, Yu, Gui, Ke, Wang, Hong, Goloub, Philippe, Zhu, Jun, Zhang, Xiaoye, Chen, Jing

2019

Overview

Multi-year observations of aerosol microphysical and optical properties, obtained through ground-based remote sensing at 50 China Aerosol Remote Sensing Network (CARSNET) sites, were used to characterize the aerosol climatology for representative remote, rural, and urban areas over China to assess effects on climate. The annual mean effective radii for total particles (ReffT) decreased from north to south and from rural to urban sites, and high total particle volumes were found at the urban sites. The aerosol optical depth at 440 nm (AOD440 nm) increased from remote and rural sites (0.12) to urban sites (0.79), and the extinction Ångström exponent (EAE440–870 nm) increased from 0.71 at the arid and semi-arid sites to 1.15 at the urban sites, presumably due to anthropogenic emissions. Single-scattering albedo (SSA440 nm) ranged from 0.88 to 0.92, indicating slightly to strongly absorbing aerosols. Absorption AOD440 nm values were 0.01 at the remote sites versus 0.07 at the urban sites. The average direct aerosol radiative effect (DARE) at the bottom of atmosphere increased from the sites in the remote areas (−24.40 W m−2) to the urban areas (−103.28 W m−2), indicating increased cooling at the latter. The DARE for the top of the atmosphere increased from −4.79 W m−2 at the remote sites to −30.05 W m−2 at the urban sites, indicating overall cooling effects for the Earth–atmosphere system. A classification method based on SSA440 nm, fine-mode fraction (FMF), and EAE440–870 nm showed that coarse-mode particles (mainly dust) were dominant at the rural sites near the northwestern deserts, while light-absorbing, fine-mode particles were important at most urban sites. This study will be important for understanding aerosol climate effects and regional environmental pollution, and the results will provide useful information for satellite validation and the improvement of climate modelling.

• Publisher: Copernicus Publications/European Geosciences Union,Copernicus GmbH,European Geosciences Union,Copernicus Publications
• Subject: Aerosol absorption / Aerosol effects / Aerosol optical depth / Aerosol optical properties / Aerosols / Air pollution / Albedo / Analysis / Anthropogenic factors / Aridity / Atmosphere / Atmospheric models / Atmospheric particulates / Atmospheric physics / Atmospheric research / Climate / Climate effects / Climate models / Climatology / Cooling / Cooling effects / Desert environments / Deserts / Detection / Dust storms / Earth / Earth Resources And Remote Sensing / Electromagnetic absorption / Environmental assessment / Environmental effects / Environmental pollution / Environmental Sciences / Methods / Metropolitan areas / Optical analysis / Optical properties / Optical thickness / Pollution / Pollution effects / Properties / Regional climates / Remote sensing / Rural areas / Satellites / Spatial distribution / Urban areas