Knowledge Resource Center for Ecological Environment in Arid Area
| An original GIS and remote sensing protocol to detect agricultural drought effects on rainfed agro-ecosystems in semi-arid developing regions: a case study for Central Mexico | |
| Sierra-Soler;Andres | |
| 出版年 | 2014 |
| 学位授予单位 | McGill University |
| 英文摘要 | Drought is a silent and pervasive phenomenon, it creeps up over weeks, months, and even years often without any warning, affecting ecosystems and human activity on a global scale. Globally droughts are one of the most devastating natural hazards in terms of the people affected and inflicting directly or indirectly economies, societies and ecosystems. As any natural hazard, the degree of exposure and the ability of systems to be resilient are directly related with the vulnerability of communities. Agricultural drought represents a great threat to poor farmers in semi-arid regions developing regions. For farmers who depend on rainfed agricultural production for self-sufficiency a drought can result in great suffering.As such there is a need to understand how droughts disturb the landscape in such regions. Satellite observations of the Earth have the potential to provide insights on vegetation conditions, crop yield and furthermore to monitor the impact of droughts. The relationship between spectral properties of vegetation and their biomass has been recognized since the first spectrometric field experiments in the 1970s. Satellite remote sensing provides a synoptic view of the land and a spatial context for measuring drought impacts which have proved to be a valuable source of spatially continuous data with improved information on monitoring vegetation dynamics. This thesis had the objective of proposing a new methodology to monitor the development of different vegetation covers in the presence of detected abnormally dry conditions and to compare this with vegetation development in periods with normal precipitation with a particular interest on rainfed agricultural lands. The analysis of the impacts of droughts on vegetation was performed with the use of remote sensing techniques. An original protocol for performing Land Use Land Cover (LULC) classification that combines climatic, topographic and reflectance information from 18 Landsat ETM+ images was applied to subsequently distinguish drought effects in different classes through the selected years. The achieved LULC classification produced overall classification accuracies ranging from 87.88% to 92.42%. Spectral indices for vegetation and soil/vegetation moisture were then used to detect anomalies in vegetation development caused by drought and furthermore, the area of water bodies was measured and compared to detect changes in water availability for irrigated crops. The proposed methodology was tested in Central Mexico to determine which growing season period could be used to detect the evolution of a drought (in this case the year 2005) and which could be applied to other semiarid regions. La sécheresse est un phénomène silencieux et omniprésent , il glisse au fil des semaines , des mois , voire des années souvent sans aucun avertissement , affectant les écosystèmes et les activités humaines à l'échelle mondiale . Sécheresses à l'échelle mondiale sont l'une des catastrophes naturelles les plus dévastatrices en termes de personnes touchées et infliger directement ou indirectement économies, les sociétés et les écosystèmes . Comme toute catastrophe naturelle , le degré d'exposition et la capacité des systèmes de résilience sont directement liés à la vulnérabilité des communautés . La sécheresse agricole représente une grande menace pour les agriculteurs pauvres dans les régions en développement des régions semi-arides . Pour les agriculteurs qui dépendent de la production agricole pluviale pour l'autosuffisance une sécheresse peuvent entraîner de grandes suffering.As comme il est nécessaire de comprendre comment la sécheresse perturbent le paysage dans ces régions. Les observations satellitaires de la Terre ont le potentiel de fournir des indications sur les conditions de végétation, le rendement des cultures et, en outre de surveiller l'impact des sécheresses . La relation entre les propriétés spectrales de la végétation et la biomasse a été reconnue depuis les premières |
| 语种 | 法语 |
| URL | http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123308 |
| 来源机构 | McGill University |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/248894 |
| 推荐引用方式 GB/T 7714 | Sierra-Soler;Andres. An original GIS and remote sensing protocol to detect agricultural drought effects on rainfed agro-ecosystems in semi-arid developing regions: a case study for Central Mexico[D]. McGill University,2014. |
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