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sur le développement des zones arides et semi-arides

Titre : Agricultural drought in Chile From the assessment toward prediction using satellite data

Sequía Agrícola en Chile : de la evaluación hacía la predicción usando datos satelitales

Auteur : Zambrano Bigiarini, Francisco Javier

Université de soutenance : Universidad de Concepción

Grade : Doctor en Ingeniería Agrícola, mención Recursos Hídricos en la Agricultura 2017

Résumé partiel
Climate change is occurring and there is a scientific consensus that human being is playing a key role by pouring greenhouses gases to the atmosphere. Temperature has been increasing globally and the precipitation patterns are changing. Regionally, since the year 2010 Chile has been experiencing which has been called a mega drought, however, it has been seen mostly in meteorological terms by analyzing precipitation deficits. Further, the future projection for Chile indicates that the precipitation will decrease in Central-South Chile, this addded to the increase on temperature likely could increase drought frequency and intensity. Also, in this regard crop yield of corn and wheat decreases are forecasted by 2050 for Chile. The study on how climate variability and human activity impact agriculture has been known as agricultural drought. One of the main factors that trigger this drought conditions is precipitation deficit, thus is crucial to understand how this depletion relates to agriculture development. Although, since 2010 Chile has been facing water shortage mostly as results of the analysis of annual precipitation, but still there is a lack of knowledge about how this mega drought is affecting agriculture over Chile. Moreover, during the growing season 2007-2008 a large part of the country experienced decreases in crop yield for which these areas were declared under drought emergency by the government. However, by analyzing the total amount of annual precipitation these years are not seen as relevant drought years. This happens in part because for vegetation is more important the timing of the rainfall deficit rather than the cumulative over a year. Thus, the study and understanding of agricultural drought and methods that could help to anticipate it are challenging. The study of agricultural drought at regional and global scale brings the problem of having enough data that allow to analyze it spatially and temporally. Nonetheless, since the 70’s the use of remote sensing data obtained from satellite to monitor the environment at global and regional scale has been highly improved, and nowadays are a key data source to support climatic and environmental studies. In that regard, there is an important amount of satellite-derived data publicly available.

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