Increased Heat Transport Through Barrow Canyon and Its Impact on Subsurface Warming in the Western Arctic Ocean

Abstract Barrow Canyon is a major conduit through which Pacific‐origin water enters the Arctic Basin. Mooring data acquired across the mouth of Barrow Canyon from 2000 to 2022 have enabled direct computation of seawater transports. No significant decadal trend in volume transport of Barrow Canyon throughflow was observed, although an upward trend of Bering Strait throughflow has been reported. Annual heat transport through the canyon varied widely, ranging from 0.93 to 7.05 TW, and larger values of heat transport occurred more often in the 2010s compared to the 2000s. The interannual variability of heat transport was not correlated with the Bering Strait heat transport, even though most of the Pacific water inflow through the Bering Strait flows along an eastern path toward Barrow Canyon during summer. Instead, year‐to‐year variation in Barrow Canyon heat transport was driven by variation in summertime sea ice coverage of the northeastern Chukchi Sea, because early ice clearance reduces sensible heat loss to thawing ice and increases direct warming of the surface water via insolation. Using sea surface temperature and wind data from the Chukchi Sea, we derived a proxy for estimating volume and heat transport through Barrow Canyon over the last 40 years. Estimated heat transport in the canyon doubled between 1980s and 2010s likely because of decreasing sea ice presence in summer. This change in heat transport has been sufficient to explain the increase in the heat content of Pacific summer water in the Canada Basin over the same interval.