Influence of the East Asia‒Pacific and Eurasian teleconnection on the summer marine heatwaves in the Japan/East Sea

Marine heatwaves (MHWs) are an escalating global issue, posing significant threats to marine ecosystems and the fisheries economy worldwide, including in the Japan/East Sea (JES). However, the influence of atmospheric circulation modes on the occurrence of MHWs in this relatively enclosed sea area remains unclear. To address this issue, this study utilizes 1982‒2023 high-resolution daily satellite sea surface temperature (SST) data and atmospheric reanalysis products to investigate the relationship between atmospheric circulation modes and MHWs in the JES. The results show that during 1982‒2023, the JES experienced severe summer MHWs, primarily driven by intense shortwave radiation linked to atmospheric activities. The East Asia-Pacific (EAP) pattern was found to influence the MHWs in the JES. Notably, we identified an interdecadal change in the relationship between MHWs and EAP patterns around 2001. Before 2001, there was a strong correlation (r = 0.68, p < 0.01) between MHWs in the JES and the EAP, but this relationship weakened significantly in the following years. During the 1982‒2000 period, MHWs in the JES were primarily influenced by tropical convection over the South China Sea and the Philippine region, which triggered poleward Rossby wave propagation. Furthermore, since 2001, MHWs have shown a strong correlation with the summer Eurasian (EU) teleconnection, a zonal wave train situated over Eurasia. The correlation between EU and MHWs has reached 0.6 ( p < 0.01) during the period from 2001 to 2023, in contrast to a weak negative correlation observed in the preceding EAP dominated period. This EU type mode is linked to warm SST anomalies in the North Atlantic and cold SST anomalies in the north of Western Europe from April to August. The Linear Baroclinic Model (LBM) and NCAR CAM5.3 can effectively validate the conclusions of the observations. • Atmospheric processes are crucial in driving marine heatwaves (MHWs) in the Japan/East Sea. • The mechanisms underlying MHWs in the Japan/East Sea have demonstrated distinct changes before and after 2001. • From 1982 to 2000, convective activity over the South China Sea and the Philippine region generated active East Asia-Pacific teleconnection wave train, which significantly influenced MHWs. • Between 2001 and 2023, SST anomalies in the North Atlantic impacted the Eurasian teleconnection wave train, thereby exerting a substantial effect on MHWs.