Date of Award

May 2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Atmospheric Sciences

First Advisor

Aaron D. Kennedy

Abstract

The El Niño Southern Oscillation (ENSO) is a common teleconnection used for seasonal forecasts over the Great Plains of the United States, where the warmer (colder) conditions are associated with the positive (negative) phase. Precipitation is more nuanced due to the impacts of single events on seasonal precipitation. Understanding how ENSO impacts temperature and precipitation events in a warming climate is vital for understanding risks to the agricultural community. Unfortunately, deterministic climate simulations complicate matters as results can vary between different models due to internal variability.This study leverages the Community Earth System Model 2 Large Ensemble (CESM2) to explore the relationship between ENSO and blizzards over the Northern Great Plains. Utilizing the 10 “Mother of All Runs” members, monthly teleconnection indices are diagnosed under a historical and future scenario, while Synoptic typing via Self Organizing Maps was used for the identification of specific atmospheric patterns. Historical analyses revealed that while ENSO characteristics aligned across datasets, CESM2 simulations exhibited biases, particularly in underestimating La Niña events and blizzard occurrences. Future projections indicate an increase in El Niño events and a decrease in ENSO durations, with corresponding shifts in blizzard climatology. However, the exclusion of meteorological variables in the analysis suggests potential inaccuracies in future blizzard predictions, warranting further investigation.

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