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| Titel |
Further evidence of important environmental information content in red-to-green ratios as depicted in paintings by great masters |
| VerfasserIn |
C. S. Zerefos, P. Tetsis, A. Kazantzidis, V. Amiridis, S. C. Zerefos, J. Luterbacher, K. Eleftheratos, E. Gerasopoulos, S. Kazadzis, A. Papayannis |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 6 ; Nr. 14, no. 6 (2014-03-25), S.2987-3015 |
| Datensatznummer |
250118523
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| Publikation (Nr.) |
 copernicus.org/acp-14-2987-2014.pdf |
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| Zusammenfassung |
| We examine sunsets painted by famous artists as proxy information for the
aerosol optical depth after major volcanic eruptions. Images derived from
precision colour protocols applied to the paintings were compared to online
images, and found that the latter, previously analysed, provide accurate
information. Aerosol optical depths (AODs) at 550 nm, corresponding to
Northern Hemisphere middle latitudes, calculated by introducing red-to-green
(R / G) ratios from a large number of paintings to a radiative transfer model,
were significantly correlated with independent proxies from stratospheric
AOD and optical extinction data, the dust veil index, and ice core volcanic
indices. AODs calculated from paintings were grouped into 50-year intervals
from 1500 to 2000. The year of each eruption and the 3 following years were
defined as "volcanic". The remaining "non-volcanic" years were used to
provide additional evidence of a multidecadal increase in the atmospheric
optical depths during the industrial "revolution". The increase of AOD at
550 nm calculated from the paintings grows from 0.15 in the middle 19th
century to about 0.20 by the end of the 20th century. To corroborate
our findings, an experiment was designed in which a master painter/colourist
painted successive sunsets during and after the passage of Saharan aerosols
over the island of Hydra in Greece. Independent solar radiometric
measurements confirmed that the master colourist's R / G ratios which were
used to model his AODs, matched the AOD values measured in situ by
co-located sun photometers during the declining phase of the Saharan
aerosol. An independent experiment was performed to understand the
difference between R / G ratios calculated from a typical volcanic aerosol and
those measured from the mineral aerosol during the Hydra experiment. It was
found that the differences in terms of R / G ratios were small, ranging
between −2.6% and +1.6%. Also, when analysing different parts of
cloudless skies of paintings following major volcanic eruptions, any
structural differences seen in the paintings had not altered the results
discussed above. However, a detailed study on all possible sources of
uncertainties involved (such as the impact of clouds on R / G ratios) still
needs to be studied. Because of the large number of paintings studied, we
tentatively propose the conclusion that regardless of the school,
red-to-green ratios from great masters can provide independent proxy AODs
that correlate with widely accepted proxies and with independent
measurements. |
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