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Accueil du site → Doctorat → Allemagne → Characterizing and modelling interacting climatic, orographic and anthropogenic influences on the landscape evolution of the upper Rio Guadalentín catchment area (Spain)

Bayerischen Julius-Mawimilians-Universität Würzburg (2006)

Characterizing and modelling interacting climatic, orographic and anthropogenic influences on the landscape evolution of the upper Rio Guadalentín catchment area (Spain)

Riedlinger, Torsten

Titre : Characterizing and modelling interacting climatic, orographic and anthropogenic influences on the landscape evolution of the upper Rio Guadalentín catchment area (Spain)

Auteur : Riedlinger, Torsten

Université de soutenance : Bayerischen Julius-Mawimilians-Universität Würzburg

Grade : Doktorgrade 2006

Résumé partiel
The presented study focused on the reconstruction of the Holocene climatological and landscape evolution for a semiarid natural and cultural environment in southeast Spain. Climatological, orographical and anthropogenic influencing factors were described in order to derive and evaluate their interrelationships. This work is based on an analysis of the subrecent regional climate, on a water balance simulation model, as well as on the integration of stratigraphic and geochemical investigations of fluvial sediments, which themselves allow interpretation of the regional climate and environment history. As a basis for comparing the climatic conditions during the Holocene, the climatic changes in the last 50 years were analysed. For that purpose spatio-temporal precipitation properties like quantity, intensity and distribution were evaluated and described. Based on various analysis techniques a detailed description of recent and subrecent pluvio-climatological control factors for the investigation area was possible. Results show that the 30 year average for annual precipitation varies between 281 and 426 mm with an increase for the upper Rio Guadalentín catchment, contrary to the postulated negative trend for the western Mediterranean. The number of precipitation days is highly variable, although a positive trend towards rainfall with high amounts of precipitation is recognized. This is important against the background of summer dryness (40 to 150 days) because intensive rainfall in early autumn potentially leads to increased topsoil erosion. The comparative annual rainfall variability within the investigation area reaches up to 36 % and therefore partially exceeds the magnitude for arid environments in North Africa. The precipitation regime varies significantly in relation to the orographic characteristics. Hence, the variations in rainfall amount, intensity, duration and occurrence depend on the surrounding relief and altitude. A water balance simulation model was adapted to semiarid conditions in order to derive possible changes within the ephemeral and periodical runoff characteristics and to calculate water balance magnitudes. Model results for the 1988 to 1993 period reveal that 87 % of the average areal precipitation of approximately 430 mm evaporates due to high air temperatures, clear skies, wind conditions, and the reduced infiltration capacity of the topsoil.

Mots clés : holocene climate change , landscape evolution , semi arid climate , hydrologic modelling , land use change

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