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| Titel |
Sensitivity and uncertainty in crop water footprint accounting: a case study for the Yellow River basin |
| VerfasserIn |
L. Zhuo, M. M. Mekonnen, A. Y. Hoekstra |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 18, no. 6 ; Nr. 18, no. 6 (2014-06-17), S.2219-2234 |
| Datensatznummer |
250120386
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| Publikation (Nr.) |
 copernicus.org/hess-18-2219-2014.pdf |
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| Zusammenfassung |
Water Footprint Assessment is a fast-growing field of research, but as yet
little attention has been paid to the uncertainties involved. This study
investigates the sensitivity of and uncertainty in crop water footprint (in
m3 t−1) estimates related to uncertainties in important input
variables. The study focuses on the green (from rainfall) and blue (from
irrigation) water footprint of producing maize, soybean, rice, and wheat at
the scale of the Yellow River basin in the period 1996–2005. A grid-based
daily water balance model at a 5 by 5 arcmin resolution was applied to
compute green and blue water footprints of the four crops in the Yellow River
basin in the period considered. The one-at-a-time method was carried out to
analyse the sensitivity of the crop water footprint to fractional changes of
seven individual input variables and parameters: precipitation (PR),
reference evapotranspiration (ET0), crop coefficient (Kc),
crop calendar (planting date with constant growing degree days), soil water
content at field capacity (Smax), yield response
factor (Ky) and maximum yield (Ym).
Uncertainties in crop water footprint estimates related to uncertainties in
four key input variables: PR, ET0, Kc, and crop calendar
were quantified through Monte Carlo simulations.
The results show that the sensitivities and uncertainties differ across crop
types. In general, the water footprint of crops is most sensitive to ET0
and Kc, followed by the crop calendar. Blue water footprints were
more sensitive to input variability than green water footprints. The smaller
the annual blue water footprint is, the higher its sensitivity to changes in
PR, ET0, and Kc. The uncertainties in the total water
footprint of a crop due to combined uncertainties in climatic inputs (PR and
ET0) were about ±20% (at 95% confidence interval). The effect
of uncertainties in ET0was dominant compared to that of PR. The
uncertainties in the total water footprint of a crop as a result of combined
key input uncertainties were on average ±30% (at 95% confidence
level). |
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