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International Institute for Geo-Information Science and Earth Observation (ITC) 2006

Agricultural drought impact assessment using remote sensing : a case study Borkhar district, Iran

Hossein Mokhtari, M. (Mohammad)

Titre : Agricultural drought impact assessment using remote sensing : a case study Borkhar district, Iran

Auteur : Hossein Mokhtari, M. (Mohammad)

Etablissement de soutenance : University of Twente International Institute for Geo-Information Science and Earth Observation (ITC)

Grade : Master of Science in Geo-Information Science and Earth Observation 2006

Résumé
Evaluating the performance of Biomass and evapotranspiration as drought indicators, could play an important role in agricultural drought impact assessment. Two models are used to calculate evapotranspiration and Biomass. Surface Energy Balance model (SEBAL) is applied to calculate actual evapotranspiration and Monteith model is used to calculate ab sorbed photosynthetically active radiation (APAR) which is linked to SEBAL model. These two models have been applied through satellite images with combination of ground data for a typical agriculture area in a semi-arid region of Borkhar Basin in Iran. This study has considered deviation of actual cr op evapotranspiration from potential evapotranspiration calculated through Penman-Monteith model and reduction in Biomass production as indicators of agricultural drought. The estimates are based on processing sixteenth high temporal resolution Terra/MODIS image that covers crop cycle and two high spatial resolutions ASTER L1A images for calibration of MODIS images for both biomass and evapotranspiration. Actual evapotranspiration calculated from SEBAL model were compared with evapotranspiration calculated from Penman-Monteith method, calculated in nonstandard condition for a weather station which was located around 24 Km from the study area. Compar ison of Results showed no significant relationship between evapotranspiration calculated from the Penman-Monteith and SEBAL model for both sugar beet and maize . Although total evapotranspirati on for sugar beet shows, about 20% lower in SEBAL model and for maize about 15% higher compare to Penman-M onteith model. This discrepancy may related to the limited number of satellite images that were used for whole season, the error that was introduced in Interpolation of actual evapotranspiration by means of reference evapotranspiration and distance about 24 Km between the study area and the weather station where data were acquired can be contributed in error. The use of more high spatial resolution image may results in more accurate estimation of biomass and evapotranspiration.

Version intégrale (ITC)

Page publiée le 4 février 2018, mise à jour le 15 octobre 2018