A new study reveals how data from a single coastal tide gauge can significantly improve predictions of internal solitary wave (ISW) activity offshore, particularly leveraging data from the Tarifa gauge located at the Strait of Gibraltar. These internal waves, which propagate through stratified waters, play significant roles in ocean mixing, sediment transport, and even impact underwater infrastructures.
Traditionally, measuring ISWs has posed substantial challenges due to the lack of high-resolution and frequent observational data. This research, conducted by multiple experts, proposes using the unique signatures of large amplitude ISWs detected at the Tarifa tide gauge to develop and validate an automated detection algorithm. The algorithm analyzes sea level fluctuations correlated with ISW occurrences, thereby providing insights previously deemed unavailable due to limited measurement capabilities.
The study observed the signatures of ISWs from high-frequency (1 minute interval) tide gauge records collected over nearly eight years, from 2015 to 2023. By applying wavelet analysis to these data, researchers successfully identified patterns of ISWs indicating their presence and dynamics.
Internal solitary waves are particularly prominent in the Strait of Gibraltar due to complex hydrodynamic interactions between the warm Atlantic waters and the saltier and denser Mediterranean currents. When these currents interact at specific locations, such as the Camarinal Sill, ISWs are generated, facilitating diapycnal mixing and enhancing the broader biological and chemical dynamism of these marine environments.
During the research process, the Tarifa gauge demonstrated its effectiveness at capturing the reflected wave signatures from the prominent eastward propagative ISWs. The culmination of data analysis confirmed previous findings where reflected waves, designated as R-waves, correlated strongly with the fluctuations captured by tide gauge measurements. A significant finding noted was, “The signature of R-waves at the Tarifa tide gauge is a reliable proxy to study the variability in the emission of I-waves at CS,” underscoring the reliability of this newly established detection method.
The findings present compelling opportunities for oceanographers and marine scientists, enhancing the ability to predict ISW activity effectively and informing strategic decisions around coastal infrastructure and marine conservation efforts. The study also emphasizes the potential broader application of similar methodologies worldwide, relying on existing tide gauge networks.
This research reveals the significant, untapped potential of tide gauges to detect ISW events, transforming them from passive data collection tools to active participants in oceanographic prediction. By enabling researchers to access long-term data series through tide gauges, the potential global applications can lead to greater insight and smarter management of our valuable oceanic resources.
Such advancements not only bolster our scientific knowledge but also encourage proactive measures needed to protect marine ecosystems from the impacts and variabilities of climate change and ocean dynamics.