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| Titel |
EMAC model evaluation in calculated aerosol and aerosol optical properties |
| VerfasserIn |
Alexander de Meij, Andrea Pozzer, Kirsty Pringle, Holger Tost, Jos Lelieveld  |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250047297
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| Zusammenfassung |
| This study evaluates global and regional aerosol optical depth (AOD) trends in view
of aerosol (precursor) emission changes between 2000 and 2009. We use AOD
products from MODIS, MISR and AERONET, and emission estimates from the
EMEP, REAS and IPCC inventories. First we compare trends in global Level 3
AOD products of MODIS, MISR and AERONET (Level 2). We find generally
negative trends over Europe and North America, whereas over South and East Asia
they are mostly positive. The negative trends over parts of Europe and North-East
America appear to be significant. Second, we analyze MODIS Level 2 AODs for
three selected regions with good data coverage (Central Mediterranean, North-East
America and East Asia) and compare with Level 3 products. This corroborates
that the 2000 - 2009 AOD trend over the Central Mediterranean is negative and
corresponds well with the MODIS Level 3 analysis. Also for North-East America
the trend is generally negative and in agreement with MODIS Level 3 products.
For East Asia the trends derived from Level 2 products are mostly positive and
correspond with the MODIS Level 3 results. Over Europe, the trends in aerosol single
scattering albedo, as derived from MISR data, appear to be positive (declining solar
radiation absorption), whereas this is not the case over the USA, though these data
are not yet validated. Third we compare trends in AOD with emission changes of
SO2, NOx, NH3 and black carbon. We associate the downward trends in AOD over
Europe and North America with decreasing emissions of SO2, NOx, and other
criteria pollutants, and consequently declining aerosol concentrations. Over East
Asia the MODIS Level 2 trends are generally positive, consistent with increasing
pollutant emissions by fossil energy use and growing industrial and urban activities. It
appears that SO2 emission changes dominate the AOD trends, although especially
in Asia NOx emissions may become increasingly important. Our results suggest
that solar brightening due to decreasing SO2 emissions and resulting downward
AOD trends over Europe may have weakened in the 2000s compared to the 1990s. |
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