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2008.07219

A Delay Equation Model for the Atlantic Multidecadal Oscillation

Swinda K.J. Falkena, Courtney Quinn, Jan Sieber, Henk A. Dijkstra

incompletemedium confidence
Category
math.DS
Journal tier
Specialist/Solid
Processed
Sep 28, 2025, 12:55 AM

Audit review

The paper correctly derives the exact two-delay boundary delay-difference system via characteristics and provides a consistent ε-regularized DDE, including first-order error terms from the MZ formalism. However, it does not supply a rigorous well-posedness analysis or an ε→0 convergence proof for the regularization. The model’s solution gives a complete diagonalization-based derivation of the delay-difference law and a standard method-of-steps/approximate-identity argument establishing convergence (with an initial-layer compatibility condition), thereby filling the paper’s analytical gap.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The manuscript convincingly derives a two-delay boundary delay model for an AMO PDE, and relates a smoothing ε-term to PDE discretization via the MZ formalism. The derivations are coherent and the numerics are supportive. To make the work mathematically complete, a short well-posedness and singular limit argument for the ε-regularized DDE should be included, along with explicit structural assumptions (retardedness, initial compatibility). These are modest additions that will strengthen the paper without changing its conclusions.