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| Titel |
An experimental detrending approach to attributing change of pan evaporation in comparison with the traditional partial differential method |
| VerfasserIn |
Tingting Wang, Fubao Sun, Jun Xia, Wenbin Liu, Yanfang Sang |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250142592
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| Publikation (Nr.) |
 EGU/EGU2017-6232.pdf |
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| Zusammenfassung |
| In predicting how droughts and hydrological cycles would change in a warming climate,
change of atmospheric evaporative demand measured by pan evaporation (Epan) is one
crucial element to be understood. Over the last decade, the derived partial differential (PD)
form of the PenPan equation is a prevailing attribution approach to attributing changes to
Epan worldwide. However, the independency among climatic variables required by the PD
approach cannot be met using long term observations. Here we designed a series of numerical
experiments to attribute changes of Epan over China by detrending each climatic variable,
i.e., an experimental detrending approach, to address the inter-correlation among climate
variables, and made comparison with the traditional PD method. The results show that the
detrending approach is superior not only to a complicate system with multi-variables and
mixing algorithm like aerodynamic component (Ep,A) and Epan, but also to a simple
case like radiative component (Ep,R), when compared with traditional PD method.
The major reason for this is the strong and significant inter-correlation of input
meteorological forcing. Very similar and fine attributing results have been achieved based on
detrending approach and PD method after eliminating the inter-correlation of input
through a randomize approach. The contribution of Rh and Ta in net radiation and
thus Ep,R, which has been overlooked based on the PD method but successfully
detected by detrending approach, provides some explanation to the comparing results.
We adopted the control run from the detrending approach and applied it to made
adjustment of PD method. Much improvement has been made and thus proven this
adjustment an effective way in attributing changes to Epan. Hence, the detrending
approach and the adjusted PD method are well recommended in attributing changes
in hydrological models to better understand and predict water and energy cycle. |
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