Two Types of Mid-High-Latitude Low-Frequency Intraseasonal Oscillations near the Ural Mountains during Boreal Summer

Abstract Two types of mid-high-latitude low-frequency intraseasonal oscillations (LF-ISOs), featuring eastward and westward propagation, have been identified over the Eurasian continent in past 37 summers (1982–2018). The propagating modes commonly a dominant periodicity 30–50 days near Ural Mountains (UM) but different origins evolutions. LF-ISO initiates eastern North America, migrates northeastward across northeastern America–western Atlantic, central western Europe, UM, then propagates southeastward to northwestern China, which is Atlantic-Eurasian continental mode. In contrast, mode quasi-circumpolar, initiating East Siberian Sea moving southwestward UM northern Europe eventually reaching Greenland Canadian Arctic Archipelago. These two LF-ISOs are accompanied by significant tropical variations with evident tropical–extratropical interactions. Meanwhile, these decadal preferences before after 2000, ascribed change both efficient kinetic energy obtained from mean flow their genesis region background associated Atlantic Oscillation/Arctic Oscillation change. This study deepens understanding subseasonal for mid-high latitudes prediction sources low-latitude regions.