Alexandros Ziogas

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  • in reply to: Communicating Confidence #2215

    Alexandros Ziogas
    Participant

    Hi,
    Communicating uncertainty is indeed a tricky part because the clients usually prefer a straight answer, a uniquely explained result, a “single value”. However, uncertainty is exactly the opposite.
    We took advantage of the SWICCA demonstrator graphical presentation of climate change results in order to convey the nature of uncertainty to our clients. We found out than once all scenarios are presented then it is easier to be accepted that all scenarios are based on current scientific knowledge and they are all equally possible. Afterwards, clients are more willing to look for trends in the results and to discuss actions based on a cloud of results which are similar rather than look for a unique answer. In fact, the initial doubts on the scientific ability to predict future change is raised when the equal probability of different scenarios is understood. We believe that SWICCA demonstrator can be a great tool for conveying the nature of uncertainty which characterises climate change.
    Regards,
    Alexandros


    Alexandros Ziogas
    Participant

    Hi,
    Due to differences identified between modeled and observed precipitation in the catchments of Evinos and Mornos, daily precipitation and temperature data provided by SWICCA, with spatial analysis of 0.5 degrees, were downscaled based on local data. Mean values, mean & variance and Full PDF correction was applied. We note that Full PDF correction led to historical time series with statistical characteristics better matching the observed time series, than BC corrected data. However, Full PDF correction led to time series for the future period which depict a significantly different climate change than the change predicted by the original, 0.5 degrees SWICCA data. This was not observed for the BC corrected time series.
    In order to cope with this issue, there was an effort to change the Full PDF correction rules applied for close-to-zero daily precipitation, since we noticed that Full PDF correction led to time series with a lot of zero daily precipitation values. This effort led to slightly better results but still the problem remained. Another correction effort was based on removing the trend from the historical 0.5 degrees time series, applying the Full PDF correction then and adding the trend back again. That approach kind of corrected the problem. However, we decided to use the BC corrected time series.
    Regards,
    Alexandros

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