Collaborative Innovation Centre on Forecast and Evaluation of Meteorological Disasters, Key Laboratory of Meteorological Disaster, Ministry of Education (KLME), International Joint Laboratory on Climate and Environment Change (ILCEC), Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044, Jiangsu, China; Department of Physics, Higher Education, Government of Khyber Pakhtunkhwa, Peshawar, 25000, Pakistan.
Collaborative Innovation Centre on Forecast and Evaluation of Meteorological Disasters, Key Laboratory of Meteorological Disaster, Ministry of Education (KLME), International Joint Laboratory on Climate and Environment Change (ILCEC), Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044, Jiangsu, China; Department of Physics, School of Sciences and Humanities, Green Fields Campus, K. L. University, Vaddeswaram 522502, Guntur, Andhra Pradesh, India.
Environ Pollut. 2019 Nov;254(Pt A):113025. doi: 10.1016/j.envpol.2019.113025. Epub 2019 Aug 7.
The present study utilizes 18 years of long-term (2001-2018) data collected from six active AERONET sites over the Indo-Gangetic Plain (IGP) and the North China Plain (NCP) areas in Southeast Asia. The annual mean (±SD) aerosol optical thickness at 440 nm (AOT) was found high at XiangHe (0.92 ± 0.69) and Taihu (0.90 ± 0.51) followed by Beijing (0.81 ± 0.69), Lahore (0.81 ± 0.43), and Kanpur (0.73 ± 0.35) and low at Karachi (0.52 ± 0.23). Seasonally, high AOT with corresponding high Ångström exponent (ANG) noticed during JJA for all sites, except Kanpur, suggesting the dominance of fine-mode particles, generally associated with large anthropogenic emissions. Climatologically, an increasing (decreasing) trend was observed over IGP (NCP) sites, with the highest (lowest) percentage of departures in AOT found over Beijing (Karachi). We further identified major aerosol types which showed the dominance of biomass burning, urban-industrial followed by the mixed type of aerosols. In addition, single scattering albedo (SSA), asymmetry parameter (ASP), volume size distribution (VSD), and complex aerosol refractive index (RI) showed significant temporal and spectral changes, illustrating the complexity of aerosol types. At last, the annual mean direct aerosol radiative forcing at the top, bottom, and within the atmosphere for all sites were found in the range from -17.36 ± 3.75 to -45.17 ± 4.87 W m, -64.6 ± 4.86 to -93.7 ± 10.27 W m, and 40.5 ± 6.43 to 68.25 ± 7.26 W m, respectively, with an averaged atmospheric heating rate of 0.9-2.3 K day. A large amount of anthropogenic aerosols showed a significant effect of heating (cooling) on the atmosphere (surface) results obviously, due to an increased rate of atmospheric heating. Therefore, the thermodynamic effects of anthropogenic aerosols on the atmospheric circulation and its structure should be taken into consideration for future study over the experimental sites.
本研究利用了来自东南亚恒河平原（IGP）和华北平原（NCP）地区的六个 AERONET 站点长达 18 年的长期（2001-2018 年）数据。在 440nm 处的气溶胶光学厚度的年平均值（±SD）（AOT）在香河（0.92±0.69）和太湖（0.90±0.51）最高，其次是北京（0.81±0.69）、拉合尔（0.81±0.43）和坎普尔（0.73±0.35），而在卡拉奇（0.52±0.23）最低。从季节上看，除了坎普尔，所有站点在 JJAS 期间都出现了高 AOT 和相应的高 Ångström 指数（ANG），这表明细颗粒模式的主导地位，通常与大量人为排放有关。气候上，IGP（NCP）站点呈增加（减少）趋势，AOT 的离差百分比最高（最低）的是北京（卡拉奇）。我们进一步确定了主要的气溶胶类型，这些类型表明生物质燃烧、城市工业以及混合气溶胶类型的主导地位。此外，单次散射反照率（SSA）、不对称参数（ASP）、体积尺寸分布（VSD）和复杂气溶胶折射率（RI）显示出显著的时间和光谱变化，说明了气溶胶类型的复杂性。最后，我们发现所有站点的年度平均直接气溶胶辐射强迫在顶部、底部和大气内部分别在-17.36±3.75 到-45.17±4.87 W/m²、-64.6±4.86 到-93.7±10.27 W/m²和 40.5±6.43 到 68.25±7.26 W/m²之间，平均大气加热率为 0.9-2.3 K/天。大量的人为气溶胶对大气（表面）产生了明显的加热（冷却）效应，这主要是由于大气加热率的增加。因此，在未来的研究中，应该考虑人为气溶胶对大气环流及其结构的热力学效应。
