Evaluating secondary inorganic aerosols in three dimensions
The spatial distribution of aerosols and their chemical composition dictates whether aerosols have a cooling or a warming effect on the climate system. Hence, properly modeling the three-dimensional distribution of aerosols is a crucial step for coherent climate simulations. Since surface measur...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-08-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/10651/2016/acp-16-10651-2016.pdf |
| Summary: | The
spatial distribution of aerosols and their chemical composition dictates
whether aerosols have a cooling or a warming effect on the climate system.
Hence, properly modeling the three-dimensional distribution of aerosols is a
crucial step for coherent climate simulations. Since surface measurement
networks only give 2-D data, and most satellites supply integrated column
information, it is thus important to integrate aircraft measurements in
climate model evaluations. In this study, the vertical distribution of
secondary inorganic aerosol (i.e., sulfate, ammonium, and nitrate) is evaluated
against a collection of 14 AMS flight campaigns and surface measurements from
2000 to 2010 in the USA and Europe. GISS ModelE2 is used with multiple aerosol
microphysics (MATRIX, OMA) and thermodynamic (ISORROPIA II, EQSAM)
configurations. Our results show that the MATRIX microphysical scheme
improves the model performance for sulfate, but that there is a systematic
underestimation of ammonium and nitrate over the USA and Europe in all model
configurations. In terms of gaseous precursors, nitric acid concentrations
are largely underestimated at the surface while overestimated in the higher
levels of the model. Heterogeneous reactions on dust surfaces are an important
sink for nitric acid, even high in the troposphere. At high altitudes,
nitrate formation is calculated to be ammonia limited. The underestimation of
ammonium and nitrate in polluted regions is most likely caused by a too
simplified treatment of the NH<sub>3</sub> ∕ NH<sub>4</sub><sup>+</sup> partitioning which
affects the HNO<sub>3</sub> ∕ NO<sub>3</sub><sup>−</sup> partitioning. |
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| ISSN: | 1680-7316 1680-7324 |