Indian Ocean warming as key driver of long-term positive trend of Arctic Oscillation ...

• Main Authors: Jeong, Yong-Cheol, Yeh, Sang-Wook, Lim, Young-Kwon, Santoso, Agus, Wang, Guojian
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Nature 2022
• Subjects: Arctic; Indian; Pacific
• Online Access: https://dx.doi.org/10.13016/m2rzcr-eibp; https://mdsoar.org/handle/11603/25251

Arctic oscillation (AO), which is the most dominant atmospheric variability in the Northern Hemisphere (NH) during the boreal winter, significantly affects the weather and climate at mid-to-high latitudes in the NH. Although a climate community has focused on a negative trend of AO in recent decades, the significant positive trend of AO over the last 60 years has not yet been thoroughly discussed. By analyzing reanalysis and Atmospheric Model Inter-comparison Project (AMIP) datasets with pacemaker experiments, we found that sea surface temperature warming in the Indian Ocean is conducive to the positive trend of AO from the late 1950s. The momentum flux convergence by stationary waves due to the Indian Ocean warming plays an important role in the positive trend of AO, which is characterized by a poleward shift of zonal-mean zonal winds. In addition, the reduced upward propagating wave activity flux over the North Pacific due to Indian Ocean warming also plays a role to strengthen the polar vortex, ...