Institute for Atmospheric and Climate Science

The SunCloud project

Upcoming events

4 Events found:

  1. Fri 27. Nov. 2015 13:30 : ETH Zentrum, CHN L 17.1
    Michael Keller : The diurnal cycle of Alpine summer convection in a convection-resolving model: evaluation with satellite data and sensitivity to atmospheric forcing
    Special Event (PhD Defense)
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  2. Mon 30. Nov. 2015 16:15 : ETH Zentrum, CAB G 11
    Dr. Silvia Kloster : Fire in Earth System Models: Climate Controls and Climate Impacts
    Kolloquium Atmos. & Klima (Kolloquium)
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  3. Mon 07. Dec. 2015 16:15 : ETH Zentrum, CAB G 11
    Dr. Ruud Dirksen : The role of the GCOS Reference Upper-Air Network (GRUAN) in climate research
    Kolloquium Atmos. & Klima (Kolloquium)
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  4. Mon 14. Dec. 2015 16:15 : ETH Zentrum, CAB G 11
    Prof. David W. J. Thompson : Climate variability and change in the Southern Hemisphere atmospheric circulation
    Kolloquium Atmos. & Klima (Kolloquium)
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Das IAC bloggt auf dem ETH-Klimablog, der Informationsplattform der ETH Zürich zum Klimawandel. Mehr auf

The SunCloud project: An initiative for a development of a worldwide sunshine duration and cloudiness observations dataset.

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 sunshine duration and cloud cover. 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 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, worldwide, main meteorological stations. Nevertheless, detailed and up-to-date analysis of sunshine duration behavior on global or hemispheric scales are still missing.

Thus, starting on 2011 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. 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. 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.


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