English

Dynamical Stability Indicator based on Autoregressive Moving-Average Models: Critical Transitions and the Atlantic Meridional Overturning Circulation

Applications 2022-11-22 v2 Atmospheric and Oceanic Physics

Abstract

A statistical indicator for dynamic stability known as the Υ\Upsilon indicator is used to gauge the stability and hence detect approaching tipping points of simulation data from a reduced 5-box model of the North-Atlantic Meridional Overturning Circulation (AMOC) exposed to a time dependent hosing function. The hosing function simulates the influx of fresh water due to the melting of the Greenland ice sheet and increased precipitation in the North Atlantic. The Υ\Upsilon indicator is designed to detect changes in the memory properties of the dynamics, and is based on fitting ARMA (auto-regressive moving-average) models in a sliding window approach to time series data. An increase in memory properties is interpreted as a sign of dynamical instability. The performance of the indicator is tested on time series subject to different types of tipping, namely bifurcation-induced, noise-induced and rate-induced tipping. The numerical analysis show that the indicator indeed responds to the different types of induced instabilities. Finally, the indicator is applied to two AMOC time series from a full complexity Earth systems model (CESM2). Compared with the doubling CO2_2 scenario, the quadrupling CO2_2 scenario results in stronger dynamical instability of the AMOC during its weakening phase.

Keywords

Cite

@article{arxiv.2203.01100,
  title  = {Dynamical Stability Indicator based on Autoregressive Moving-Average Models: Critical Transitions and the Atlantic Meridional Overturning Circulation},
  author = {Marie Rodal and Sebastian Krumscheid and Gaurav Madan and Joseph Henry LaCasce and Nikki Vercauteren},
  journal= {arXiv preprint arXiv:2203.01100},
  year   = {2022}
}

Comments

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