Winter Arctic Oscillation, Siberian High and East Asian Winter Monsoon

TLDR

The study investigates how the winter Arctic Oscillation and Siberian High affect the East Asian winter monsoon. The Arctic Oscillation directly alters surface temperature, sea‑level pressure, and the 500‑hPa East Asian trough north of 35°N, while the Siberian High mainly influences surface temperature south of 50°N in East Asia, the northwest Pacific, and the South China Sea, with the Arctic Oscillation dampening high‑latitude Siberian High effects. The Arctic Oscillation and Siberian High independently influence the East Asian winter monsoon, but the Siberian High exerts a stronger, more direct impact on sea‑level pressure and northerly coastal winds than the Arctic Oscillation.

Abstract

In this note, we investigate the impacts of the winter Arctic Oscillation (AO) and Siberian High (SH) on the East Asia winter monsoon (EAWM). It is found that the winter AO and the SH are relatively independent of each other in influencing the EAWM. The winter AO influences directly surface air temperature (SAT), sea level pressure (SLP) and the East Asian Trough at 500 hPa over the region northwards of 35°N in East Asia rather than through its impact on the SH. Compared with influences of the winter AO, the SH shows more direct and significant influences on the EAWM, particularly on SLP and northerly wind along the East Asian Coast. Impacts of the SH on the SAT occur primarily in the southwards of 50°N over East Asia, the northwestern Pacific and the South China Sea, because the AO suppresses the SH's influences in high latitudes of Asian Continent and the some subarctic regions.