Date of Graduation


Document Type


Degree Type



Eberly College of Arts and Sciences


Geology and Geography

Committee Chair

Amy Hessl

Committee Co-Chair

Branden McNeil

Committee Member

Neil Pederson


The influence of increasing temperatures on hydrologic regimes across Mongolia is difficult to evaluate from a spatial perspective, particularly at fine resolutions. Therefore, networks of tree-ring chronologies are a valuable means of assessing regional and local variability in hydroclimate while placing recent moisture trends in a historical context. Tree-ring data are particularly useful in Mongolia, where instrumental records are spatially and temporally limited. Here, I present two chapters that are essentially related and complement one another. The first chapter seeks to identify tree-growth anomaly regions (i.e. inferred hydroclimatic regions) across north-central Mongolia based on a network of 21 tree-ring chronologies. I applied a rotated principal component analysis (RPCA) to the tree-ring network and identified four tree-growth anomaly regions, which display unique hydroclimatic variability through time. Chapter Two evaluates the tree-growth anomaly regions in terms of ranked drought and pluvial events. From a spatial perspective, these analyses demonstrate the extent of interregional and intraregional hydroclimatic variability across the network; in particular, the results highlight that the Eastern and Western regions of the network are especially unique from one another. Each chapter is presented in a journal article format and consists of its own abstract.