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Titre : Spatio-temporal and frequency analysis of drought events via remote sensing data : Case study of Aegean region

Uzaktan algılama verileri kullanılarak kuraklık olaylarının alansal, zamansal ve frekans analizleri : Ege bölgesi örneği

Auteur : KOCAASLAN KARAMZADEH Semra

Université de soutenance : İstanbul Teknik Üniversitesi

Grade : Doktora Tezi 2022

Résumé partiel
The foremost of the problems facing our age is undoubtedly global warming and the climate change it brings. Climate change is one of the most important problems facing the world, as it is predicted to alter climate patterns and increase the frequency of extreme weather events. It is obvious that this change has negative consequences that may directly or indirectly affect human life, such as displacement of climatic regions, melting of land and sea glaciers, rising sea levels, severe weather events, more frequent effects of floods, drought and desertification. Drought, conversely, is a disaster that is difficult to understand compared to other disasters due to its complex structure. It is a slow-spreading, silent disaster that that can affect large areas. It is difficult to determine its characteristics such as its beginning and end, duration of effect, and severity. It is considered a relative situation, not an absolute one. It can occur in both high and low rainfall areas and in almost any climate regime, even in deserts and rainforests. In the literature, drought has been divided into four main classes according to the varying impact areas and the parameters used to distinguish it. These have been defined as meteorological, agricultural, hydrological, and socioeconomic. Drought varieties occur at different time scales and are closely related to each other. Basically, meteorological as a result of the lack of precipitation, then agricultural due to the lack of water in the soil, hydrological losses due to the decrease in rivers and underground water reserves, and socio-economic drought due to all social and environmental consequences. On the other hand, it is very important to detect and follow up the drought events in the past, to predict the possible risks that may arise in the future, to establish early warning systems in this direction and to take the necessary measures within the scope of planning the mitigate against drought. While traditional drought monitoring and evaluation methods are generally based on non-continuous station-based meteorological data, remote sensing technology is a strong alternative for such studies in terms of providing fast information production and spatially continuous information with the synoptic view it offers. Remotly sensed data has some advantages over meteorological data, such as the scope of observation, direct imaging, and the ability to capture the effects of non-meteorological factors. In this sense, high spatial and temporal resolution data sets obtained from satellites constitute an important resource for studies conducted to evaluate drought even in areas where there are no meteorological stations or where their distribution is sparse. The main purpose of this thesis is to investigate the usability of near real-time, mostly free or very economical satellite data for monitoring and forecasting drought events, and to demonstrate that it is a supportive and necessary element for the existing traditional drought monitoring methods especially in Turkey.

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