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Assessing trends in atmospheric circulation patterns across North America
Author(s) -
Smith Erik T.,
Obarein Omon,
Sheridan Scott C.,
Lee Cameron C.
Publication year - 2021
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.6983
Subject(s) - geopotential height , climatology , environmental science , atmospheric circulation , atmosphere (unit) , meteorology , geography , precipitation , geology
Circulation patterns (CPs) are discrete categorizations of spatial fields of atmospheric conditions, often used to examine the interaction between the overlying atmosphere and surface weather. Examining changes in the frequency of these atmospheric CPs may therefore 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 to classify CPs from 500 mb geopotential heights (500z) and mean sea‐level pressure (MSLP) for five regions across North America, using two different reanalysis datasets. Trends in CPs (from 1979 to 2018) from both the North American Regional Reanalysis (NARR) and the recently released ERA5 datasets are compared using a new method in which the CPs from the ERA5 dataset are based on the principal components of the NARR data. This results in a more direct comparison between the CPs of each dataset. z500 CP trends were generally larger than the MSLP CP trends and the NARR CP trends were generally larger than the ERA5 CP trends. Furthermore, the most extreme summer‐dominant CPs were found to have increased significantly over the 40‐year study period in all five regions for both the NARR and ERA5 CPs.