Summertime Heat Across the United States

• Main Author: Smith, Tiffany Townsend
• Other Authors: Zaitchik, Benjamin F., Waugh, Darryn W.
• Format: Thesis
• Language: English
• Published: Johns Hopkins University 2016
• Subjects: climate; heat waves; North Atlantic Oscillation; random forest; United States; North Atlantic; North Atlantic oscillation
• Online Access: http://jhir.library.jhu.edu/handle/1774.2/58726

Extreme summertime heat has been the most deadly natural hazard in the United States over the past 30 years and is projected to become more intense, more frequent and longer lasting in the second half of the century. We take this as motivation to improve our understanding of the drivers in summertime heat across the Continental United States (CONUS), and provide a framework to discussing results from studies with diverse motivations. This dissertation attempts to (1) create a baseline in understanding in the way heat waves are defined and how this impacts conclusions of the patterns and trends of heat waves, (2) investigate large scale drivers of summertime temperature on seasonal timescales across variable-informed regions of CONUS, and (3) identify the impact of North Atlantic Oscillation (NAO) definition on local heat waves as defined by two relevant definitions. We find that (1) positive trends in heat waves are seen across most of the United States where spatial patterns differ between definitions, (2) temperature variability is sensitive to climate processes across CONUS regions, notably though that nonlinear models produce improvement in explaining these relationships, and (3) that by defining NAO by its centers of action, rather than phase, we increase our ability to model heat waves in Baltimore, MD. This work will provide an outline for discussing results from heat wave studies with diverse motivations, as well as deepen our understanding of the large-scale drivers of summertime heat with the intention of informing and improving seasonal forecasting and ultimately mitigate negative impacts heat has on the human population.