第一届未来大气科学论坛

The Siberian storm track, located in the central part of the Eurasian continent, is an essential component of the Northern Hemisphere storm track system and the most active region for synoptic-scale eddies over land. Anomalies in the Siberian storm track are not only closely linked to local weather and climate but also, within the context of large-scale circulation, have potential impacts on the climate variability in downstream East Asia. This study investigates the interannual relationship between the winter Siberian storm track (WSST) and East Asian winter precipitation and explores the underlying physical processes. The results show that a significant negative correlation between WSST intensity and precipitation along southeastern coastal China and the East China Sea. An intensified WSST corresponds to suppressed precipitation, driven by effects of anomalous atmospheric circulation and moisture transport. Mechanistically, the enhanced WSST triggers a distinct circulation pattern characterized by low-level northerly wind anomalies over eastern China and upper-level positive vorticity anomalies over the East China Sea. These anomalies induce cold advection and upper-level convergence, promoting subsidence that inhibits ascending motion in key precipitation regions. Concurrently, moisture flux divergence associated with the anomalous northerlies reduces moisture availability, compounding the precipitation deficit. The anomalous large-scale atmospheric circulation and baroclinicity may be sustained by the WSST-mean flow interaction. The feedback on the basic flow induced by the WSST anomalies tends to maintain the enhanced atmospheric baroclinicity, thereby perpetuating both the WSST anomalies themselves and anomalies in the atmospheric circulation. Furthermore, synoptic-scale disturbances originating from the winter Siberian storm track propagate southeastward, generating cyclonic circulation anomalies over the East China Sea. These disturbances enhance low-level convergence aloft while suppressing near-surface uplift, creating unfavorable conditions for precipitation formation. This research provides insights into how atmospheric circulation affects precipitation patterns, with implications for climate change adaptation and short-term climate prediction in East Asia.

Siberian storm track,East Asia,winter precipitation,interannual variation