Royal Dutch Meteorological Institute; Ministery Of Infrastructure And The Environment

Publications, presentations and other activities
Improved inversion of aerosol components in the atmospheric column from remote sensing data
2020
by Y. Zhang (AirCAS, Beijing), Z. Li (AirCAS, Beijing), Y. Chen (CMA, Beijing), G. de Leeuw (KNMI), C. Zhang (AirCAS, Beijing)Y. Xie (AirCAS, Beijing)K. Li (AirCAS, Beijing)

Knowledge of the composition of atmospheric
aerosols is important for reducing uncertainty in climate assessment.
In this study, an improved algorithm is developed
for the retrieval of atmospheric columnar aerosol components
from optical remote sensing data. This is achieved by
using the complex refractive index (CRI) of a multicomponent
liquid system in the forward model and minimizing the
differences with the observations. The aerosol components
in this algorithm comprise five species, combining eight subcomponents
including black carbon (BC), water-soluble organic
matter (WSOM) and water-insoluble organic matter
(WIOM), ammonium nitrate (AN), sodium chloride (SC),
dust-like content (DU), and aerosol water content in the fine
and coarse modes (AWf and AWc). The calculation of the
CRI in the multicomponent liquid system allows for the separation
of the water-soluble components (AN, WSOM and
AWf) in the fine mode and SC and AWc in the coarse mode.
The uncertainty in the retrieval results is analyzed based
on the simulation of typical models, showing that the complex
refractive index obtained from instantaneous optical–
physical inversion compares well with that obtained from
chemical estimation. The algorithm was used to retrieve the
columnar aerosol components over China using the groundbased
remote sensing measurements from the Sun–sky radiometer
Observation NETwork (SONET) in the period from
2010 to 2016. The results were used to analyze the regional
distribution and interannual variation. The analysis shows
that the atmospheric columnar DU component is dominant
in the northern region of China, whereas the AW is higher
in the southern coastal region. The SC component retrieved
over the desert in northwest China originates from a paleomarine
source. The AN significantly decreased from 2011
to 2016, by 21.9 mgm􀀀2, which is inseparable from China’s
environmental control policies.

Bibliographic data
Zhang, Y., Z. Li, Y. Chen, G. de Leeuw, C. Zhang, Y. Xie and K. Li, Improved inversion of aerosol components in the atmospheric column from remote sensing data
Atm. Chem. Phys., 2020, 20, 12795-12811, doi:https://doi.org/10.5194/acp-20-12795-2020.
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