Spatial and Temporal Variability of Midwest Winter Severity

• Main Author: Wright, Jefferson David
• Format: Text
• Language: unknown
• Published: OpenSIUC 2019
• Subjects: Arctic; Pacific
• Online Access: https://opensiuc.lib.siu.edu/theses/2577; https://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=3591&context=theses

Severe winter weather is something that impacts everyone in some way, and there are always questions regarding how severe a winter season has been and how external factors can influence the severity of winter. Characteristics of severe winter weather include large snowfall accumulations, persistent snow depths, extreme cold temperatures, or extended cold snaps, and the Midwest United States is subject to these conditions on a multitude of spatial and temporal scales. A method of quantifying the severity of winter known as the Accumulated Winter Season Severity Index (AWSSI) has been employed for this study, and utilizes daily records of the aforementioned winter severity characteristics to generate a value that can represent how severe an individual winter season has been, as well as the long term average winter severity for a given location. The variability in Midwest winter severity has been a topic of many previous studies, but a study regarding the long term changes as well as the drivers of winter severity with respect to the AWSSI has not been accomplished. Using daily records of snowfall, snow depth, maximum temperature, and minimum temperature, the goal of this study is to use the AWSSI to quantify these long term changes and impacts of different teleconnection phases on Midwest winter severity. The teleconnection patterns explored in this study include the El Niño Southern Oscillation (ENSO), the Pacific-Decadal Oscillation (PDO), the Arctic Oscillation (AO), and the Pacific North American (PNA) pattern. The analysis is divided into three phases consisting of (1) establishing a general winter climatology within the study area, (2) determining the long term changes in winter severity and the associated parameters, and (3) examining the impacts of teleconnection patterns on the inter-annual variability in Midwest winter severity.