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Universidad Nacional de Cuyo (1998)

Estimación de la evapotranspiración real regional a partir de datos satelitales

Bermejillo, Adriana

Titre : Estimación de la evapotranspiración real regional a partir de datos satelitales

Auteur : Bermejillo, Adriana

Université de soutenance : Universidad Nacional de Cuyo

Grade : Maestría en Riego y Drenaje 1998

Résumé
The aim of the present work was to determine the Actual Evapotranspiration (AET) at regional scale by using the NOAA-AVHRR meteorological satellite data. The results were compared with those calculated from a hydrological simulation model. Thirty images including the Mendoza North oasis, in Argentine were analyzed to estimate AET. The normalized vegetation index (NDVI) was obtained using the information of the C1(visible) and C2 (near infrared) channels to follow the crop canopy yearly evolution. The surface temperature (Ts) was calculated with the Split-Windows method, using the information of thermal Infrared (C4 and C5) channels. The cumulative sum of the differences between the surface temperature, Ts, and the air temperature, Ta, commonly known as S.D.D.(Stress Degree Day) was calculated. It allows the global appraisal of the hydric stress characteristics at regional level. Based on (Ts-Ta) data, the AET was calculated from the net radiation and A-B coefficients estimated from the crop canopy structure. A simplified energy balance equation, developed by Jackson(1977) and Seguin (1983) was used : AET = NR + A - B (Ts –Ta). Later, values of emissivity were included in the calculations. The B coefficient was varied, taking into account the land use of each subregion, in which the study area was divided. In the final stage, AET data obtained from the various methods and the ones simulated by the hydrological model, were statistically compared. The final conclusion was that : the estimation of the AET at regional scale by means of satellite data agrees with that of the hydrological model in most of the cases. It is simple to calculate, making the developed methodology easily adaptable to other oases in the region.

mots clés : Actual evapotranspiration (aet) - Remote sensing - Irrigated oases

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Page publiée le 4 avril 2019