Publications des scientifiques de l'IRD

Hoedjes Joost, Chehbouni Abdelghani, Jacob Fréderic, Ezzahar J., Boulet Gilles. (2008). Deriving daily evapotranspiration from remotely sensed instantaneous evaporative fraction over olive orchard in semi-arid Morocco. Journal of Hydrology, 354 (1-4), p. 53-64. ISSN 0022-1694.

Titre du document
Deriving daily evapotranspiration from remotely sensed instantaneous evaporative fraction over olive orchard in semi-arid Morocco
Année de publication
2008
Type de document
Article référencé dans le Web of Science WOS:000257005800005
Auteurs
Hoedjes Joost, Chehbouni Abdelghani, Jacob Fréderic, Ezzahar J., Boulet Gilles
Source
Journal of Hydrology, 2008, 354 (1-4), p. 53-64 ISSN 0022-1694
Hydrology and crop water management require daily values of evapotranspiration ET at different time-space scale. Sun synchronous optical remote sensing, which allows for the assessment of ET with high to moderate spatial resolution, provides instantaneous estimates during satellites overpass. Then, usual solutions consist of extrapolating instantaneous to daily values by assuming that evaporative fraction EF is constant throughout the day, providing that daily available energy AE is known. The current study aims at deriving daily ET values from ASTER derived instantaneous estimates, over an olive orchard in a semi-arid region of Moroccan. It has been shown that EF is almost constant under dry conditions, but it depicts a pronounced concave up shape under wet conditions. A new heuristic parameterization is then proposed, which is based on the combination of routine daily meteorological data for characterizing atmospheric dependence, and on optical remote sensing based estimates of instantaneous EF values to take into account the dependence on soil and vegetation conditions. Using the same type of approach, a similar parameterization is next developed for AE. The validation of both approaches shows good performances. The overall method is finally applied to ASTER data. Though performances are reasonably good, their moderate reduction is ascribed to errors on remotely sensed variables. Future-works will focus on method portability since its empirical formulation does not account for the direct stomata[ response to water availability, as well as on application over different surface and climate conditions.
Plan de classement
Hydrologie [062] ; Bioclimatologie [072]
Localisation
Fonds IRD [F B010042643]
Identifiant IRD
fdi:010042643
Contact