The Possible Linkage Between Barents–Kara Sea Ice Loss and Summer Precipitation Variability Over East Asia

Arctic sea ice (ASI) loss is a prominent indicator of climate system change, affecting mid to low latitudes weather and climate through intricate interactions and feedback processes. However, it remains unclear whether ASI loss significantly affects summer precipitation in East Asia at interannual scales. This analysis explores how the spring Barents–Kara (BK) sea ice anomaly is linked to summer precipitation interannual variability in East Asia (100°−122.5°E, 21°–36°N) since 1979 by using reanalysis data sets and Community Atmosphere Model 5.4 (CAM 5.4) simulation experiments. Both observational results and numerical simulation results indicate that the summer precipitation anomalies associated with the BK sea ice anomaly exhibit a dipole pattern over East Asia. In response to persistent BK sea ice loss from spring to summer, a Rossby wave is generated, which extends from the Arctic to the Northwest Pacific. This atmospheric circulation anomalies weakens the Northwest Pacific Subtropical High and strengthens the western Northwest Pacific summer monsoon (WNPSM). The intensified WNPSM not only inhibits the transport of subtropical water vapor from the South Asian monsoon to North China but also induces divergence of the lower troposphere in North China and convergence over South China. Consequently, summer rainfall increases in the southern part of East Asia and decreases in the northern region. Additionally, the CAM 5.4 simulation experiments successfully replicate key atmospheric responses to BK sea ice loss. The results indicate that the spring ASI may affect summer precipitation over East Asia independently of the interannual variability in the Arctic Oscillation and El Niño‒Southern Oscillation.