Modelação de complexidade reduzida da adaptação de ilhas-barreira à subida do nível do mar

The main aim of MOBILE is to produce a simplified, yet robust, model, suitable for providing meaningful projections for barrier island morphologic adaptation to SLR and changes in storminess. MOBILE will build on advances in RCMs, balancing model complexity reduction (necessary to achieve long-term simulations) and comprehensiveness of physical process detail translated into the model (necessary to retain sound physical basis and show good skill (French et al., 2016)). To this aim, the project will i) implement a modelling scheme able to adequately reproduce barrier island morphological response to a range of drivers (including human- and climate-related) and over distinct timescales (interannual, multidecadal, centennial), thus addressing a critical gap of timescale integration in coastal modelling; and ii) use this model in climate scenarios, to assess the potential future barrier adaptation and to test mitigation strategies. The work aspires to advance the field of applied coastal geomorphology and current capacity in modelling multidecadal to centennial coastal change. As most RCMs have focused on reproducing theoretical barrier responses and were tested in hypothetical scenarios (e.g. BRIE; Nienhius & Lorenzo-Trueba (2019)), real-world testing is a major challenge that MOBILE will undertake. Effectively reproducing morphologic changes in the challenging environment of east RF will be a significant step forward, bringing RCM techniques closer to more accurate simulations and, hopefully, to broader applicability in other barrier systems and conditions. At the same time, projections of barrier resilience pathways in a future of rising SLs can help formulate suitable solutions, attuned to inherent, previously demonstrated, resilience characteristics (Kombiadou et al., 2020a). Projected system tipping points and permanence of regime shifts (e.g. barrier drowning or rollover) will help identify conditions that could lead to loss of adaptive capacity. Such regime shifts will most likely have significant (socioeconomic and) environmental impacts, as, aside from direct habitat losses (e.g. dunes), severe perturbations like barrier drowning can cascade onto dependant habitats (e.g. lagoon marshes). Given the regional and national importance of the ecosystem services of RF and of barrier island systems globally, the future projections of geomorphic adaptation and resilience can be instrumental in preparing for, and tackling, adverse effects and climate-related risks. To achieve these goals, MOBILE will address the following individual challenges: • incorporate unrepresented morphological units of dune (improving overwash exposure) and backbarrier marsh (accounting for accommodation space for transgression) to the RCM. • include adequate process complexity to the RCM, necessary to reproduce the impact of major factors (natural and human-derived) controlling changes over short- (i.e. storms), medium- (i.e. sediment availability, wave climate variability) and long-term (i.e. SLR) scales, aiming at achieving acceptable model accuracy over the hindcasting period. • evaluate uncertainties and minimise error propagation in forecasting simulations, to produce grounded projections of barrier adaptation and, in extension, future resilience, to climate change. • identify mitigation measures that can assist in anticipating potential system tipping points and identifying critical moments of action to strengthen system resilience in the future.