Ishmael-Lalla, M., Deonarine, A., Gopaul, N., and Seeram, S., 2024. Understanding Trinidad and Tobago's oceanography using hydrodynamic and spectral wave models. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 680-684. Charlotte (North Carolina), ISSN 0749-0208.

Trinidad and Tobago (T&T) rely on marine resources for its economy, including the offshore oil and gas industry, fisheries, and tourism. T&T waters have complex characteristics that require a nuanced approach to modelling. Trinidad's western coastline borders the shallow Gulf of Paria (GoP), contrasting with Tobago's proximity to the continental shelf edge. These islands are influenced by seasonal freshwater runoff from the Orinoco and Amazon Rivers and are impacted by the passage of North Brazil Current (NBC) Rings and seasonal tropical storms and hurricanes. These conditions highlight the need to understand the islands' varying circulation patterns and wave regimes. A 3D Hydrodynamic (HD) model and a Spectral Wave (SW) Model were developed for T&T and the Eastern Caribbean Region. These models were used to provide a comprehensive understanding of the oceanographic conditions around these Small Island Developing States (SIDS). The models, assimilated with datasets specific to the region, underwent extensive validation using measured datasets, operating in forecast mode until 2021. The 3D HD model verified the existence of a clockwise gyre within the GoP and captured NBC Rings that result in current speeds exceeding 1.5 m/s off the east coast of Trinidad. The general current patterns for the Tobago's southwest Atlantic coast show westerly and north-westerly currents, while southeast Tobago showed predominately east to northeasterly flow. The Caribbean coast of Tobago show variable current patterns with island-wake eddies being captured by the model. The SW model provided insights into the wave climate for the region such as the high-wave energy experienced off the east coast of Trinidad, with an average wave height of 2 m contrasting with the low-energy GoP, dominated by local winds and northerly swell. Tobago's Atlantic coast also exhibits a bi-modal sea state, while its Caribbean coast, is sheltered and protected by coral reefs. These models are essential for predicting oil spills, coral larvae dispersion, coastal vulnerability, environmental impacts, and for mangrove flushing, helping to mitigate environmental damage, protect marine biodiversity, and enhance coastal resilience.