Decadal coherence of Arctic thermohaline staircases

Thermohaline staircase layers have been consistently observed in the Arctic Ocean for over 50 years. Previous studies demonstrate that these structures exhibit large-scale spatial coherence.  However, on time scales beyond a few years, both the coherence and evolution of the layers are unknown. Using Ice-Tethered Profiler data from 2005--2022 in the Beaufort Gyre Region, we track staircase layers across time and space with an unsupervised clustering method. Individual layers are found to be coherent across the entire 17-year time period, with properties that appear to evolve on 40--50 year timescales or longer. This establishes, for the first time, the decadal-scale coherence of thermohaline staircases in the Arctic Ocean. Moreover, we find that the observed changes are not consistent with the staircase being in a state of equilibrium, but rather support the hypothesis that it is decaying slowly from an initial or on-going perturbation.