Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Master → Pays Bas → 2018 → Monitoring land restoration projects of Justdiggit in Kenya, using downscaled passive microwave remote sensing products of VanderSat

Delft University of Technology (TU Delft) 2018

Monitoring land restoration projects of Justdiggit in Kenya, using downscaled passive microwave remote sensing products of VanderSat

Mulder, Martijn

Titre : Monitoring land restoration projects of Justdiggit in Kenya, using downscaled passive microwave remote sensing products of VanderSat

Auteur : Mulder, Martijn

Université de soutenance : Delft University of Technology (TU Delft)

Grade : Master 2018

Résumé partiel
The growing world population and climate change have resulted in increasing stress on the Earth’s ecosystems. Especially the overexploitation of agricultural land, overgrazing and extreme droughts have resulted in land degradation, often called desertification. This leads to the disappearing of natural vegetation, the loss of soil quality, lower production capacity in agriculture and increased water scarcity, which is most severe on drylands like the African continent. Globally, organizations such as the United Nations Convention to Combat Desertification (UNCCD) are fighting land degradation by implementing sustainable farming practices and supporting re-vegetation projects such as the Green Wall Initiative in Africa, often using ancient water harvesting techniques. Justdiggit, a Dutch NGO, is currently working on land restoration projects and dug over 72,000 water-retaining semi-circular bumps, or ’bunds’, in Kenya. By retaining rainwater in these bunds, water is given the time to infiltrate into the soil, erosion rates by overland flow are reduced, while vegetation recovers and on the long termcan take over the function of the bunds. Although the first results of the bunds at small scale are promising, the impact of the projects of Justdiggit has never been quantified on a large scale in terms of the amount of water that’s retained, increase of vegetation and decrease of surface temperature.As dense in-situ networks are expensive and have difficulties in capturing the large spatial variability of parameters such as soil moisture and temperature, often remote sensing (satellite observation) is used, which does well in measuring spatial variability on large scales. However, as optical remote sensing is often affected by cloud cover, data availability is limited. Furthermore, it is difficult to translate optical vegetation parameters such as the Normalized Difference Vegetation Index (NDVI) to vegetation biomass, as these only observe the surface of the canopy. Passive microwave remote sensing, which is measured in the microwave part of the electromagnetic spectrum, has proven to be very accurate in determining parameters such as soil moisture content, surface temperature and vegetation optical depth (VOD, related to vegetation thickness and water content)

Présentation

Page publiée le 7 avril 2021