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Titel |
The SunCloud project: worldwide compilation of long-term series of sunshine duration and cloudiness observations |
VerfasserIn |
Arturo Sanchez-Lorenzo, Enric Pallé, Martin Wild, Josep Calbó, Michelle Brunetti, Gerald Stanhill, Rudolf Brázdil, Mariano Barriendos, Paulo Pereira, Cesar Azorin-Molina |
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 |
250044318
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Zusammenfassung |
One problem encountered when establishing the causes of global dimming and brightening is
the limited number of long-term solar radiation series with accurate and calibrated
measurements. For this reason, the analysis is often supported and extended with the use of
other climatic variables such as diurnal temperature range, cloud cover, evaporation,
visibility, or sunshine duration records. Moreover, it is of vital importance to study the
reliability of the “early brightening” identified by different studies during the first
half of the 20th century, which cannot be detected by using the current downward
solar radiation dataset. Therefore proxy variables are required again. Specifically,
sunshine duration is defined as the amount of time usually expressed in hours that
direct solar radiation exceeds a certain threshold (usually taken at 120 W m-2).
Consequently, this variable can be considered as an excellent proxy measure of
global and direct solar radiation at interannual and decadal time scales, with the
advantage that measurements of this variable were initiated in the late 19th century
in different main meteorological stations. Nevertheless, detailed and up-to-date
analysis of sunshine duration behavior on global or hemispheric scales are still
missing.
Thus, in the framework of different research projects we will engage a worldwide
compilation of the longest daily or monthly sunshine duration series from the late 19th
century until present, using data freely available on the Internet or by means of
direct contacts with meteorological institutions/individual researchers with access to
long-term sunshine databases. We also plan to digitize long-term sunshine duration
series when these become available only in analog format. Several quality control
checks and homogenization methods will be applied to the generated sunshine
dataset.
The relationship between the more precise downward solar radiation series from the
Global Energy Balance Archive (GEBA) and the homogenized sunshine series will be studied
in order to reconstruct global and regional solar irradiance at the Earth’s surface since the late
19th century. Equally, we plan to calibrate sunshine duration measurements against planetary
albedo estimations from the Earthshine measurements and other satellite radiation
data.
Since clouds are the main cause of interannual and decadal variability of radiation
reaching the Earth’s surface, as a complement to the long-term sunshine series we will also
compile worldwide surface cloudiness observations.
With this abstract we seek to encourage the climate community to contribute with their
own local datasets to the SunCloud project. In the near future we will create a webpage with
the main details of this project. |
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