A Multi-Decade Tracer Study of the Circulation and Spreading Rates of
Atlantic Water in the Arctic Ocean
Abstract
In this contribution we present tritium-3He (3H-3He) apparent ages and
hydrographic data from 21 expeditions spanning 27 years of Arctic Ocean
section work (1987 to 2013) to estimate flow paths and spreading
velocities of the Atlantic Waters (AW) circulation on a pan-Arctic
scale. Tracer data independently reveal and add a time dimension to the
well-organized boundary current that cyclonically flows along the
continental slope and add insights into the other circulation branches
of the Atlantic layer, hypothesized to be guided by deep topography
(Rudels, et al., 1994). Mean spreading velocities differ between the
individual branches of the overall circulation pattern. The velocity of
the boundary current, as derived from tracer measurements, is
approximately 0.8 to 1.5 cm s-1, with no significant difference between
the upper and lower Atlantic Water layer. The tritium-3He tracer data
show that within the limits of our method the current flow system has
been stable over the study period.