Distinct Eurasian Teleconnection Wave Trains Contributing to the Intraseasonal Variations of East Asian Jet Streams

Abstract

As essential upstream circulation regimes, the Eurasian wave trains can exert influence on the East Asian jet variations on intraseasonal time scale. Nonetheless, their propagation characteristics and dynamic effects need further illustration. This study identifies that the intraseasonal variations of East Asian polar-front jet and subtropical jet, manifesting as their concurrent intensity and location changes, are preceded by Eurasian wave trains originating from the Iceland and Norwegian Sea. According to the mid-high latitude wave train structures, the conventional Eurasian pattern (EU) and Scandinavian pattern (SCAND) lead the jet variations by 1 and 2∼3 days, respectively, facilitating more organized wave structures, spreading local oscillations in East Asia to trans-Eurasian circulation realignment, and amplifying the jet variabilities. Atlantic SST anomalies play an important role in stimulating the upstream Rossby wave sources of different teleconnection wave trains, through inducing descending motions and convergence anomalies in upper troposphere.