 |
| Titel |
HESS Opinions "A perspective on isotope versus non-isotope approaches to determine the contribution of transpiration to total evaporation" |
| VerfasserIn |
S. J. Sutanto, B. van den Hurk, P. A. Dirmeyer, S. I. Seneviratne, T. Röckmann, K. E. Trenberth, E. M. Blyth, J. Wenninger, G. Hoffmann |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 18, no. 8 ; Nr. 18, no. 8 (2014-08-04), S.2815-2827 |
| Datensatznummer |
250120423
|
| Publikation (Nr.) |
 copernicus.org/hess-18-2815-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| Current techniques to disentangle the evaporative fluxes from the continental
surface into a contribution evaporated from soils and canopy, or transpired
by plants, are under debate. Many isotope-based studies show that
transpiration contributes generally more than 70% to the total
evaporation, while other isotope-independent techniques lead to considerably
smaller transpiration fractions. This paper provides a perspective on
isotope-based versus non-isotope-based partitioning studies. Some
partitioning results from isotope-based methods, hydrometric measurements,
and modeling are presented for comparison. Moreover, the methodological
aspects of the partitioning analysis are considered, including their
limitations, and explanations of possible discrepancies between the methods
are discussed. We suggest sources of systematic error that may lead to biases
in the results, e.g., instruments inaccuracy, assumptions used in analyses,
and calibration parameters. A number of comparison studies using isotope-based
methods and hydrometric measurements in the same plants and climatic
conditions are consistent within the errors; however, models tend to produce
lower transpiration fractions. The relatively low transpiration fraction in
current state-of-the-art land-surface models calls for a reassessment of the
skill of the underlying model parameterizations. The scarcity of global
evaporation data makes calibration and validation of global
isotope-independent and isotope-based results difficult. However, isotope-enabled land-surface and global climate modeling studies allow for the evaluation
of the parameterization of land-surface models by comparing the computed
water isotopologue signals in the atmosphere with the available remote
sensing and flux-based data sets. Future studies that allow for this evaluation
could provide a better understanding of the hydrological cycle in vegetated
regions. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|