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| Titel |
Global and regional trends of aerosol optical depth over land and ocean using SeaWiFS measurements from 1997 to 2010 |
| VerfasserIn |
N. C. Hsu, R. Gautam, A. M. Sayer, C. Bettenhausen, C. Li, M. J. Jeong, S.-C. Tsay, B. N. Holben |
| 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 ; 12, no. 17 ; Nr. 12, no. 17 (2012-09-10), S.8037-8053 |
| Datensatznummer |
250011433
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| Publikation (Nr.) |
 copernicus.org/acp-12-8037-2012.pdf |
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| Zusammenfassung |
| Both sensor calibration and satellite retrieval algorithm play an important
role in the ability to determine accurately long-term trends from satellite
data. Owing to the unprecedented accuracy and long-term stability of its
radiometric calibration, SeaWiFS measurements exhibit minimal uncertainty
with respect to sensor calibration. In this study, we take advantage of this
well-calibrated set of measurements by applying a newly-developed aerosol
optical depth (AOD) retrieval algorithm over land and ocean to investigate
the distribution of AOD, and to identify emerging patterns and trends in
global and regional aerosol loading during its 13-yr mission. Our
correlation analysis between climatic indices (such as ENSO) and AOD
suggests strong relationships for Saharan dust export as well as
biomass-burning activity in the tropics, associated with large-scale
feedbacks. The results also indicate that the averaged AOD trend over global
ocean is weakly positive from 1998 to 2010 and comparable to that observed
by MODIS but opposite in sign to that observed by AVHRR during overlapping
years. On regional scales, distinct tendencies are found for different
regions associated with natural and anthropogenic aerosol emission and
transport. For example, large upward trends are found over the Arabian
Peninsula that indicate a strengthening of the seasonal cycle of dust
emission and transport processes over the whole region as well as over
downwind oceanic regions. In contrast, a negative-neutral tendency is
observed over the desert/arid Saharan region as well as in the associated
dust outflow over the north Atlantic. Additionally, we found decreasing
trends over the eastern US and Europe, and increasing trends over countries
such as China and India that are experiencing rapid economic development. In
general, these results are consistent with those derived from ground-based
AERONET measurements. |
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