Distinct dynamic processes in 10–25-day and 25–70-day variability of the Siberian High

Focusing on the intraseasonal variability (ISV) of the Siberian high (SH), this study found that the SH presents two main periods of 10–25 and 25–70 days, which dominated the cold waves in the winter of 1995/96 and 2005/06 over eastern China (EC), respectively. The influence of these two ISV on East Asian climate is reflected in the evaluation of the East Asian winter monsoon and surface air temperature. The southeastward and downward Rossby wave activity indicates that the upper-level Ural anticyclone is the key to the SH ISV. By utilizing a transformed vorticity budget analysis, distinct dynamic processes in 10–25-day and 25–70-day variability of the SH were further revealed. Forcing from the mean flow acts as a guiding role in both 10–25-day and 25–70-day variability that induces the Ural anticyclone to propagate westward and eastward, respectively. Forcing from the ISV flow is similar to that from the mean flow with a smaller intensity. The dynamic synoptic eddy feedback positively contributes to both the 10–25-day and 25–70-day variability. It promotes (restrains) the westward (eastward) propagation of the Ural anticyclone in the 10–25-day (25–70-day) variability, which may be the main reason for these two distinct ISV of the SH.