The North Atlantic and the Middle East: Investigating climate dynamics and variability in a water scarce region.

摘要

This thesis represents the results of an investigation of climate change in the Middle East extending from the Holocene into the modern day. Its focus is on links between Tigris-Euphrates streamflow and large-scale climate variability associated with the North Atlantic sector. Special attention is paid to understanding physical processes, both natural and anthropogenic, that impact society in this historically rich yet water scarce region. Chapters 2 and 3 investigate interannual through centennial climate variability recorded in modern instrumental and paleoclimate data. The largest natural climate phenomenon affecting the Middle East is the North Atlantic Oscillation (NAO), which exhibits variability on interannual, decadal, and possibly longer timescales. Chapters 4 and 5 are dedicated to extending current NAO indices into the past, using a combination of ice cores, tree rings, and instrumental data, by creating a 350 year tree ring record of Turkish precipitation. An ocean general circulation model (OGCM) is employed in Chapter 6 and Appendix B to investigate the dynamic response of the North Atlantic Ocean to NAO-like forcing. The aim here is to address questions of predictability surrounding this powerful yet poorly understood phenomenon.