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Understanding regional sea level variations is crucial for assessing coastal vulnerability, with accurate sea level data playing a pivotal role. Utilizing historical sea level marigrams can enhance datasets, but current digitization techniques face challenges such as bends and skews in paper charts, impacting sea level values. This study explores often‐overlooked issues during marigram digitization, focusing on the case study of Dún Laoghaire in Ireland (1925–1931). The methodology involves digitizing the original marigram trace and underlying grid to assess offsets at the nearest ft (foot) interval on the paper chart, corresponding to changes in the water level trace for each hour interval. Subtracting the digitized value from the known value (the actual measurement) allows for the determination of differences, which are then subtracted from each hourly trace value. After adjusting for offsets ranging from −3.962 to 13.716 mm (millimetres), the study improves the final accuracy of sea level data to approximately the 10 mm level. Notably, data from 1926 and 1931 exhibit modest offsets (<7 mm), while other years show more substantial offsets (>9–14 mm), emphasizing the importance of adjustments for accuracy. Such 10 mm accuracy is compatible with requirements of the Global Sea Level Observing System. Comparing the adjusted digitized data with other survey data shows similar amplitudes and phases for Dún Laoghaire in both the historical and modern datasets, and there is an overall mean sea level rise of 1.5 mm/year when combined with the available data from the Dublin region. [ABSTRACT FROM AUTHOR]

The summer of 2023 experienced several climate extremes, including record-low sea ice in the Antarctic, heatwaves in southern Europe and the southern United States/Mexico, and the highest sea-surface temperatures (SSTs) in the North Atlantic since satellite records began. In the eastern North Atlantic, west of Ireland, a severe marine heatwave (MHW) occurred, with SSTs reaching 4°C above average. MHWs have a significant impact on ocean ecosystems, and while studies on MHWs in the North Sea and English Channel exist, research on MHWs in Irish waters is limited. The MHW activity in June 2023 was the highest ever recorded in the waters west of Ireland, and there has been a linear positive trend in MHWs in June since 2000. Despite cooling temperatures in Irish waters since 2007, the increase in MHWs suggests that extreme ocean warming is affecting these waters. The MHW of June 2023 could serve as a warning for the future. [Extracted from the article]

Scientific and societal interest in the relationship between the Atlantic Meridional Overturning Circulation (AMOC) and U.S. East Coast sea level has intensified over the past decade, largely due to (1) projected, and potentially ongoing, enhancement of sea level rise associated with AMOC weakening and (2) the potential for observations of U.S. East Coast sea level to inform reconstructions of North Atlantic circulation and climate. These implications have inspired a wealth of model‐ and observation‐based analyses. Here, we review this research, finding consistent support in numerical models for an antiphase relationship between AMOC strength and dynamic sea level. However, simulations exhibit substantial along‐coast and intermodel differences in the amplitude of AMOC‐associated dynamic sea level variability. Observational analyses focusing on shorter (generally less than decadal) timescales show robust relationships between some components of the North Atlantic large‐scale circulation and coastal sea level variability, but the causal relationships between different observational metrics, AMOC, and sea level are often unclear. We highlight the importance of existing and future research seeking to understand relationships between AMOC and its component currents, the role of ageostrophic processes near the coast, and the interplay of local and remote forcing. Such research will help reconcile the results of different numerical simulations with each other and with observations, inform the physical origins of covariability, and reveal the sensitivity of scaling relationships to forcing, timescale, and model representation. This information will, in turn, provide a more complete characterization of uncertainty in relevant relationships, leading to more robust reconstructions and projections. Plain Language Summary: Sea level along the U.S. East Coast is influenced by changes in the density and currents of the North Atlantic Ocean. Indeed, there are simple theoretical considerations that relate indices of basin‐scale flow to coastal sea level. Such a relationship could be leveraged to predict future sea level changes and coastal flooding given an expected change in climate and ocean circulation. Alternatively, it could be used to reconstruct ocean circulation from sea level measurements. This paper reviews the nature of this relationship and whether, and when, it is evident in climate models and observations. Although the current generation of large‐scale climate and ocean models generally show an antiphase relationship between basin‐scale ocean current strength and coastal sea level, the spatial pattern of sea level change differs from theory and between models. Supported by existing and emerging research, the authors hypothesize that these deviations result from important physical processes occurring on the continental shelf and slope, and the complexities of the 3‐dimensional ocean circulation. A quantitative assessment of the importance of these processes is critical for understanding past and future climate and sea level changes in this heavily populated and vulnerable region. Key Points: The relationship between the AMOC and coastal sea level is important to flood risk projections and ocean circulation reconstructionsThe amplitude and pattern of sea level variability associated with AMOC variations is location, forcing, timescale, and model dependentFuture research should address the complex spatiotemporal structure of AMOC and the role of near‐coast ageostrophic processes [ABSTRACT FROM AUTHOR]

The signature was evident across the whole south coast of Ireland (seen here from Castletownbere to Dunmore East) and likely driven by a ridge of high pressure that propagated across the south of Ireland at a similar time. A meteotsunami was observed across the south coast of Ireland on the afternoon of Saturday the 18th June 2022. The abrupt rise and fall in atmospheric pressure over the south of Ireland on the 18 June and the absence of any notable seismic event provides a likely explanation for the driver of the waves seen on the Irish south coast. [Extracted from the article]