the 22nd Pacific−Asian Marginal Seas meeting (PAMS)

The Alaskan Stream is one of the key boundary currents in the subarctic North Pacific, playing a crucial role in the redistribution of heat, freshwater, and nutrients along the Aleutian Arc. An intense mesoscale eddy field south of Amukta Pass (Aleutian Islands) facilitates the southward advection of water properties, yet the role of this eddy activity in enabling cross-jet transport through the Alaskan Stream has remained unquantified. This paper examines cross-jet transport of Bering Sea waters from Amukta Pass through the Alaskan Stream using Lagrangian modeling in the AVISO high-resolution (1/8°) surface velocity field over a 30-year period (1993–2023). Passive markers were deployed daily in the strait, and their transport was tracked to the southern section along 50°N.
The analysis identified episodes of intense water transport from the Bering Sea into the Pacific Ocean through Amukta Pass. The main characteristics of the episodes were determined: duration, intensity (number of markers), and travel time. Multi-year periods with no southward transport of Bering Sea waters into the Pacific Ocean were identified.
Our results reveal that effective water transport is a rare process with a probability of only ~2.6%. It was established that the key transport mechanism is the interaction of anticyclonic–cyclonic eddy dipoles south of the strait.
The analysis shows significant decadal variability, with extended quiescent periods (1994–1998 and 2014–2021) punctuated by episodes of intense transport. Remarkably, the four most recent episodes (2022–2023) account for more than half of all transported particles, suggesting a recent intensification of cross-jet exchange. Transit times from the pass to 50°N average ~2 months, ranging from 29 days to 135 days.
These findings demonstrate that transport through Amukta Pass is a highly intermittent yet potentially increasing contributor to Bering Sea–Pacific exchange, with implications for understanding climate-scale variability in the region's ecosystem dynamics.

Alaskan Stream,the Bering Sea,Amukta Pass,mesoscale eddies,cross-jet transport,lagrangian modeling