Evidence for Increased Waviness of the Northern Hemisphere Wintertime Polar and Subtropical Jets
Speaker: Jonathan Martin, Professor, Atmospheric and Oceanic Sciences, UW-Madison
A feature-based metric of the waviness of the wintertime, Northern Hemisphere polar and subtropical jets is developed and applied to three different reanalysis data sets. Analysis of the seasonal average waviness over the time series of the various data sets reveals that both jets have become systematically wavier while exhibiting no trends in their average speeds. The waviness of each jet evolves fairly independently of the other in most cold seasons and the slow northward creep of the polar jet is statistically significant. Finally, comparison of the composites of the waviest and least wavy seasons for each species reveals that such interannual variability is manifest in familiar large-scale circulation anomalies.