Abstracts Category : Other

Understanding the Arctic Hydroclimate Using the Regional Arctic System Model

by Joseph Johnston Hamman

The importance of understanding the Arctic climate system is underscored by the recent and unprecedented observed changes in key climatic processes across the region, and the potential for these changes to impact natural and human activities in coming decades. Warming associated with global climate change is expected to bring further changes to the Arctic cryosphere as well as the broader regional and global climate systems. My research has focused on the development and application the Regional Arctic System Model (RASM). RASM is a fully-coupled regional Earth system model (ESM) applied over a large Pan- Arctic domain. The development of RASM has been motivated by the need to improve multi-decadal simulations of high-latitude climate and to advance our understanding of the coupled interactions between individual components within the Arctic climate system. In this dissertation, I present analysis related to the development, evaluation, and application of the components of RASM that simulate land surface processes with the overarching goal of better understanding the Arctic hydroclimate. This dissertation was made up of three core chapters. In Chapter 3, I introduce a novel coupling of the Variable Infiltration Capacity (VIC) model within RASM, evaluating the performance of the VIC compared to observations and other model based datasets. In Chapter 4, I present a new river routing scheme (RVIC) for earth system models, again evaluating the model in comparison to in situ observations and model based datasets. This chapter also presents the development of a new coastal streamflow dataset for ocean modeling applications. Finally, in Chapter 5, RASM was used to evaluate how changes in the sea ice cover in the Arctic Ocean impacted precipitation patterns over land.Advisors/Committee Members: Nijssen, Bart (advisor).