Arctic warming as a potential trigger for the warm blob in the northeast Pacific

The northeast (NE) Pacific has experienced significant marine heatwaves (MHWs) in recent years, commonly known as “warm blobs.” This study examines the impact of Arctic warming, particularly in the Eastern Siberian-Chukchi Sea (ES-CS) region, on the occurrence of these warm blobs during boreal winters. We found that Arctic warming triggers a positive phase of the Tropical/Northern Hemisphere-like (TNH-like) atmospheric circulation, creating a pronounced high-pressure system over the Alaskan region. This system leads to easterly wind anomalies that weaken prevailing westerlies, reducing heat loss from the ocean to the atmosphere and cold advection in the upper ocean. Consequently, sea surface temperatures rise, favoring the development of warm blobs. A numerical experiment confirmed that the projected changes in the ES-CS region impact warm blobs occurrences by inducing this high-pressure system, linking Arctic warming to MHWs in the NE Pacific.