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| Titel |
Aerosol forcing efficiency in the UVA region from spectral solar irradiance measurements at an urban environment |
| VerfasserIn |
S. Kazadzis, N. Kouremeti, A. Bais, A. Kazantzidis, C. Meleti |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 27, no. 6 ; Nr. 27, no. 6 (2009-06-23), S.2515-2522 |
| Datensatznummer |
250016564
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| Publikation (Nr.) |
 copernicus.org/angeo-27-2515-2009.pdf |
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| Zusammenfassung |
| Spectral Ultraviolet (UV) measurements using a Brewer MKIII double
spectroradiometer were used for the determination of the aerosol forcing
efficiency (RFE) under cloud free conditions at Thessaloniki, Greece for the
period 1998–2006. Using measured spectral UVA irradiance in combination with
synchronous aerosol optical depth (AOD) measurements at 340 nm, we calculated
the seasonal and the percent RFE changes with the help of radiative transfer
model calculations used for cloud and aerosol free conditions reference. The
calculated RFE for the 325–340 nm wavelength integral was found to be
−0.71±0.30 W m−2/τs340 nm and corresponds to a mean
calculated RFE% value of −15.2%±3.8% (2 σ) per unit of τs340 nm,
for the whole period. This indicates a mean reduction of
15.2% of the 325–340 nm irradiance for a unit of aerosol optical depth
slant column increase. Lower RFE% was found during summertime, which is a
possible indication of lower absorbing aerosols. Mean AOD slant at 340 nm
for the city of Thessaloniki were processed in combination with RFE% and a mean
monthly UVA attenuation of ~10% for the whole period was revealed.
The nine years' analysis results showed a reduction in RFE%, which provides a
possible indication of the changes in the optical properties over the city
area. If such changes are only due to changes in the aerosol absorbing
properties, the above finding suggests a 2% per decade increase in UVA
due to changes in the aerosol absorption properties, in addition to the
calculated increase by 4.2%, which is attributed only to AOD decrease at
Thessaloniki area over the 1998–2006 period. |
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