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| Titel |
Using the Relationship between MODIS Aerosol Optical Thickness and OMI Trace Gas Columns to better understand Aerosol Formation and Chemical Composition |
| VerfasserIn |
Pepijn Veefkind, Folkert Boersma, Jun Wang, Pieternel Levelt |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250041853
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| Zusammenfassung |
| Aerosols are one of the leading uncertainties in global and regional climate change. One of
the most important reasons for the limited understanding of the effects of aerosols
is their strong temporal and spatial variability in chemical composition and size
distribution. Important anthropogenic sources for aerosols are transportation, power plants,
industries and biomass burning. Natural sources include windblown desert dust, sea
spray, biogenic emissions, volcanoes, and biomass burning. Together, these sources
form a complex chemical mixture of desert dust, sea salt, sulfates, nitrates and
organic material. To better understand the Earth’s climate system, accurate knowledge
is needed on the complex relation between the emissions of precursor gases and
primary aerosol particles, and aerosol composition. Satellite measurements have the
horizontal and temporal coverage to assess the global effect of aerosols on climate. In
addition to the information on aerosols, tropospheric columns of nitrogen dioxide
(NO2), formaldehyde (HCHO) and sulfur dioxide (SO2) can be observed from
space.
In this contribution, the spatial and temporal correlations between AOT and tropospheric
columns of NO2, SO2 and HCHO are used to derive information on the composition of the
aerosols particles. Spatial correlation between AOT and NO2 indicate that the aerosols are
from combustion processes, such as fossil fuel and biomass burning. The AOT to NO2 ratio
provides zeroth order information on the combustion sources. This ratio is low for regions
dominated by controlled fossil fuel combustion and high for biomass burning regions,
whereas the difference of this ratio between these regions can be more than two orders of
magnitude. Overall the GEOS-CHEM simulations can reproduce the observed AOT-NO2
ratios well. Spatial correlation between AOT and NO2 is found for many of the
industrialized ad biomass burning regions in the world. Correlations with HCHO
are especially important in biomass burning regions, and in industrial regions in
Southeast Asia. Over the Southeastern United States and Southern China a seasonal
maximum in AOT and HCHO is observed which is related to biogenic sources. We
propose to use the relationship between AOT and precursor gases observed from
space as an indicator for the extent of which combustion occurs in a controlled way. |
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