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Rigorosum Zeynab Foroozan – 15.12.2020

Stable isotope variations in tree rings as indicators of environmental change and paleohydroclimate variability in north Iran

Zeynab Foroozan (FAU)

Betreuer: Prof. Dr. Achim Bräuning

Wann: Dienstag, 15.12.2020
Wo: Aufgrund der noch immer geltenden Ausführungsbestimmungen zur Promotionsprüfung vom 20.04.2020 muss die Prüfung leider unter Ausschluss der Öffentlichkeit stattfinden.

Precise knowledge about the long-term hydroclimatic variability is essential to analyze the impact of natural and anthropogenically induced climate change, especially in arid to semi-arid regions. In this context, this research explores the potential of stable isotopes in tree-ring cellulose as a natural climate proxy for paleohydroclimate reconstruction and understanding of long-term regional climate variability in northern semi-arid regions of Iran. We investigate the ecological responses of two tree species belonging to different plant functional types, an evergreen conifer (Juniperus polycarpos) and a broadleaved deciduous oak (Quercus macranthera), growing under distinct climate conditions to their environments and recent climate change. We present the first stable oxygen tree-ring isotope chronology for paleohydroclimatic investigations in Iran and reconstruct hydroclimatic variability for the country’s northern semi-arid region spanning the period 1515–2015. The reconstructed precipitation provides evidence on i) the magnitude of inter-annual and long-term variability in regional precipitation, ii) the frequency, intensity, and duration of dry/wet events; and iii) the influence of regional atmospheric weather circulation and variable strength of the westerlies on precipitation variations at our study site.