Spatial Heterogeneity in the Concurrent Variations of the Boreal Summer Jet Streams and the Linkage to Temperature Anomalies

Abstract During boreal summer, the polar front jet (PJ) and the subtropical jet (SJ) exhibit regional heterogenous variability that strongly influences climate. However, previous studies have mainly focused on specific regions, with limited attention to a hemispheric perspective. In this study, we investigate the concurrent variations of the two jets from a hemispheric viewpoint. Based on centers of maximum upper‐level zonal wind variability, we define indices for the two jets to quantify their meandering variations. Four configurations of concurrent variations of the two jets are identified by the combinations of the two indices, and these are closely linked to the anomalies in the meridional temperature gradient and eddy kinetic energy. Notably, as both jets are in their negative phases, the most pronounced upper‐level zonal wind anomalies occur. This configuration is associated with a positive circumglobal teleconnection (CGT) phase, leading to widespread negative surface air temperature (SAT) anomalies, particularly over northeastern North America, the Mediterranean, and eastern Asia. Quantitative analysis using the temperature tendency equation demonstrates that horizontal temperature advection is the dominant term through which jet variability regulates SAT anomalies. This study provides new insights into the physical links between jet configurations and SAT anomalies on the hemispheric scale.