Earth and Space Science (Sep 2021)
Relationship Between Atmospheric Teleconnections and the Northern Hemisphere's Circumpolar Vortex
Abstract
Abstract The Northern Hemispheric circumpolar vortex (NHCPV) is the hemispheric‐scale, middle‐ and upper‐tropospheric wind belt circumnavigating the North Pole. It is delineated by the well‐known polar front jet stream, and it bends poleward at ridges and equatorward at troughs at various amplitudes and positions over time. Previous work assessed the accuracy of representing the NHCPV using a new technique through correlations to air‐sea teleconnections known to be related to broad‐scale, extratropical steering circulation at the monthly scale. Results of that work suggested that the method allows for notable improvements in the calculation of area and circularity of the 500‐hPa manifestation of the NHCPV. Because using monthly averaged data to represent the NHCPV may oversimplify analyses, especially for identifying meteorological impacts, this research employs the same technique for identifying the daily NHCPV. Results suggest that CPV area and circularity are even more closely related to variability in the North Atlantic Oscillation (NAO), Pacific/North American pattern, and (especially) Arctic Oscillation (AO) teleconnections, and the El Niño/Southern Oscillation phenomenon at the daily scale than at the monthly scale. A principal components analysis reveals the extent of the interrelationships between the teleconnections and NHCPV area and circularity. Results generally affirm that both the individual teleconnections, especially the NAO and AO, and interdependencies among these teleconnections and others, are strongly related to the NHCPV area and circularity. These findings are important because low‐ and high‐frequency variability in the amplitudes and positions of the undulations in the broad‐scale flow influence weather systems that exert important impacts on society.
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