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Trends in atmospheric circulation patterns across North America

Authors: Erik Smith*, Kent State University
Topics: Climatology and Meteorology, Environmental Science, Physical Geography
Keywords: climate, synoptic climatology, extremes, weather, North America, climate change
Session Type: Paper
Presentation File: No File Uploaded


Large-scale circulation of the Earth’s atmosphere impact surface weather and climate across the Earth. Examining the changes in these atmospheric circulation patterns (CPs) may help us better understand the relationship between a changing climate and the occurrence of extreme weather events. In this study, we use self-organized maps (SOMs) to classify atmospheric patterns from 1979 – 2018 of 500 mb geopotential heights (500z) and mean sea-level pressure (MSLP) for five regions across North America. Trends in CPs are calculated using reanalysis data from both the North American Regional Reanalysis (NARR) and recently released ERA5 datasets, then compared using a new method in which the atmospheric patterns from the ERA5 dataset are based on the principal components of the NARR data. This results in a more direct comparison between the pattern classifications of each dataset. The edges of the NARR domain and topographically diverse regions, such as the Rocky Mountains, exhibited the largest differences between the two datasets. The most extreme summer CPs were found to have increased significantly over the 40-year study period in several regions.

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