Dust aerosol properties and radiative forcing observed in spring during 2001-2014 over urban Beijing, China
Dust aerosol properties and radiative forcing observed in spring during 2001-2014 over urban Beijing, China
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2001-2014年北京城区春季沙尘气溶胶特性及辐射强迫观测
DOI：
10.1007/s11356-016-6727-9
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发表时间：
2016
影响因子：
5.8
通讯作者：
Li Mei
中科院分区：
文献类型：
--
作者：
Yu Xingna;Lu Rui;Kumar K. Raghavendra;Ma Jia;Zhang Qiuju;Jiang Yilun;Kang Na;Yang Suying;Wang Jing;Li Mei
中国，对2001年至2014年春季北京上空沙尘气溶胶的地面特征(光学和辐射特性)进行了调查。2001-2014年春季的季节平均气溶胶光学厚度(AOD)在440 nm处约为0.78。在沙尘日，气溶胶光学厚度较高与较低的恩斯特伦指数有关。春季AE440-870的平均值约为1.0，表明该地区以细颗粒物为主。回溯轨迹分析表明，沙尘是从内蒙古和蒙古干旱地区的沙漠带到北京的。气溶胶体积大小分布呈双峰分布，最大峰值出现在粗略模式下(特别是沙尘日，随着体积浓度的增加)。沙尘日的单次散射反照率(SSA)随波长增大而增大，说明有更多的散射粒子存在。此外，在沙尘日，折射率的复数部分(实部和虚部)表现出明显的特征，虚值较低(也有散射)。根据Santa Barbara DISORT大气辐射传输模式计算了沙尘日和非沙尘日的短波(Sw；0.2-4.0mμm)和长波(LW；4-100mμm)气溶胶辐射强迫(ARF值)，并估算了相应的加热率和强迫效率。因此，西南(LW)ARF在北京上空的TOA和BOA都产生了显著的降温(增温)效应。
The ground-based characteristics (optical and radiative properties) of dust aerosols measured during the springtime between 2001 and 2014 were investigated over urban Beijing, China. The seasonal averaged aerosol optical depth (AOD) during spring of 2001–2014 was about 0.78 at 440 nm. During dust days, higher AOD occurred associated with lower Ångström exponent (AE). The mean AE440–870in the springtime was about 1.0, indicating dominance of fine particles over the region. The back-trajectory analysis revealed that the dust was transported from the deserts of Inner Mongolia and Mongolia arid regions to Beijing. The aerosol volume size distribution showed a bimodal distribution pattern, with its highest peak observed in coarse mode for all episodes (especially for dust days with increased volume concentration). The single scattering albedo (SSA) increased with wavelength on dust days, indicating the presence of more scattering particles. Furthermore, the complex parts (real and imaginary) of refractive index showed distinct characteristics with lower imaginary values (also scattering) on dust days. The shortwave (SW; 0.2–4.0 μm) and longwave (LW; 4–100 μm) aerosol radiative forcing (ARF) values were computed from the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model both at the top of atmosphere (TOA) and the bottom of atmosphere (BOA) during dust and non-dust (dust free) days, and the corresponding heating rates and forcing efficiencies were also estimated. The SW (LW) ARF, therefore, produced significant cooling (warming) effects at both the TOA and the BOA over Beijing.