| Title | In situ vertical characteristics of optical properties and heating rates of aerosol over Beijing |
| Authors | Tian, Ping Liu, Dantong Zhao, Delong Yu, Chenjie Liu, Quan Huang, Mengyu Deng, Zhaoze Ran, Liang Wu, Yunfei Ding, Shuo Hu, Kang Zhao, Gang Zhao, Chunsheng Ding, Deping |
| Affiliation | Beijing Key Lab Cloud Precipitat & Atmospher Wate, Beijing 100089, Peoples R China Zhejiang Univ, Sch Earth Sci, Dept Atmospher Sci, Hangzhou 310027, Zhejiang, Peoples R China China Meteorol Adm, Field Expt Base Cloud & Precipitat Res North Chin, Beijing 100089, Peoples R China Univ Manchester, Ctr Atmospher Sci, Sch Earth & Environm Sci, Manchester M13 9PL, Lancs, England Chinese Acad Sci, Inst Atmospher Phys, Key Lab Middle Atmosphere & Global Environm Obsev, Beijing 100029, Peoples R China Chinese Acad Sci, Inst Atmospher Phys, CAS Key Lab Reg Climate Environm Temperate East A, Beijing 100029, Peoples R China Peking Univ, Dept Atmospher & Ocean Sci, Beijing 100871, Peoples R China |
| Keywords | BLACK-CARBON BROWN CARBON LIGHT-ABSORPTION SOLAR ABSORPTION CHINA WAVELENGTH POLLUTION AETHALOMETER ALBEDO WINTER |
| Issue Date | 3-Mar-2020 |
| Publisher | ATMOSPHERIC CHEMISTRY AND PHYSICS |
| Abstract | Characterizing vertical profiles of aerosol optical properties is important because relying on only the surface or column-integrated measurements cannot unambiguously constrain the radiative impacts of aerosol. This study presents series of vertical profiles of in situ measured multi-wavelength optical properties of aerosols during three pollution events from November to December 2016 over the Beijing region. For all pollution events, the clean periods (CPs) before pollution initialization showed a higher scattering Angstrom exponent (SAE) and a smaller asymmetry parameter (g) with relatively uniform vertical structures. The heavy pollution periods (HPs) showed an increased particle size, causing these parameters to vary in the opposite way. During the transition periods (TPs), regional transport of aged aerosols at higher altitudes was found. The Aerosol Robotic Network (AERONET) aerosol optical depth (AOD) matched the in situ measurements within 10 %; however the AERONET absorption optical depth (AAOD) was 10 %-20% higher than the in situ measurements, and this positive discrepancy increased to 30% at shorter wavelengths. The absorption of brown carbon (BrC) was identified by the increased-absorption Angstrom exponent (AAE), and the heating rate of black carbon (BC) and BrC was estimated by computing the spectral absorption coefficient and actinic flux calculated by a radiative transfer model. BC and BrC had a heating rate of up to 0.18 and 0.05Kh(-1) in the planetary boundary layer (PBL), respectively, during the pollution period. The fraction of BrC absorption increased from 12% to 40% in the PBL from the CP to the HP. Notably, a higher contribution of BrC heating was found above the PBL under polluted conditions. This study paints a full picture of shortwave heating impacts of carbonaceous aerosols during different stages of pollution events and highlights the increased contribution of BrC absorption especially at higher altitudes during pollution. |
| URI | http://hdl.handle.net/20.500.11897/587025 |
| ISSN | 1680-7316 |
| DOI | 10.5194/acp-20-2603-2020 |
| Indexed | SCI(E) Scopus |
| Appears in Collections: | 物理学院 |
