Causal Loop Analysis of coastal geomorphological systems

摘要: As geomorphologists embrace ever more sophisticated theoretical frameworks that shift from simple notions of evolution towards single steady equilibria to recognise the possibility multiple response pathways and outcomes, morphodynamic modellers are facing problem how keep track an ever-greater number system feedbacks. Within coastal geomorphology, capturing these feedbacks is critically important, especially as focus activity shifts reductionist models founded on sediment transport fundamentals synthesist ones intended resolve emergent behaviours at decadal centennial scales. This paper addresses challenge mapping feedback structure processes controlling geomorphic behaviour with reference illustrative applications Causal Loop Analysis two study cases: (1) erosion–accretion graded (mixed) beds, (2) local alongshore fluxes sand-rich shorelines. These case examples chosen account their central role in quantitative modelling geomorphological futures they illustrate different types causation. loop diagrams, a form directed graph, used distil reveal, advance modelling, multi-response outcomes. In bed, up three outcomes (no response, disequilibrium states) can be derived qualitative stability analysis. For shoreline case, fundamentally responses (diffusive anti-diffusive), triggered by small changes cross-shore position, inferred purely through analysis causal pathways. Explicit depiction feedback-structure diagrams beneficial when developing numerical explore morphological futures. By explicitly included neglected within model, modeller readily assess if critical loops included.