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| Titel |
Sensitivity of potential evaporation estimates to 100 years of climate variability |
| VerfasserIn |
R. P. Bartholomeus, J. H. Stagge, L. M. Tallaksen, J. P. M. Witte |
| 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 ; 19, no. 2 ; Nr. 19, no. 2 (2015-02-24), S.997-1014 |
| Datensatznummer |
250120635
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| Publikation (Nr.) |
 copernicus.org/hess-19-997-2015.pdf |
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| Zusammenfassung |
| Hydrological modeling frameworks require an accurate representation of
evaporation fluxes for appropriate quantification of, e.g., the water
balance, soil moisture budget, recharge and groundwater processes. Many
frameworks have used the concept of potential evaporation, often estimated
for different vegetation classes by multiplying the evaporation from a
reference surface ("reference evaporation") by crop-specific scaling
factors ("crop factors"). Though this two-step potential evaporation
approach undoubtedly has practical advantages, the empirical nature of both
reference evaporation methods and crop factors limits its usability in
extrapolations under non-stationary climatic conditions. In this paper,
rather than simply warning about the dangers of extrapolation, we quantify
the sensitivity of potential evaporation estimates for different vegetation
classes using the two-step approach when calibrated using a non-stationary
climate. We used the past century's time series of observed climate,
containing non-stationary signals of multi-decadal atmospheric oscillations,
global warming, and global dimming/brightening, to evaluate the sensitivity
of potential evaporation estimates to the choice and length of the
calibration period. We show that using empirical coefficients outside their
calibration range may lead to systematic differences between process-based
and empirical reference evaporation methods, and systematic errors in
estimated potential evaporation components. Quantification of errors provides
a possibility to correct potential evaporation calculations and to rate them
for their suitability to model climate conditions that differ significantly
from the historical record, so-called no-analog climate conditions. |
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