Abstract/Summary

Meteorological tsunami or meteotsunami are globally occurring shallow water waves with a period of between 2 to 120 minutes and are a result of sudden pressure changes and wind stress from moving atmospheric systems, causing destruction and loss of life. In recent decades meteotsunami have garnered attention, particularly within the United Kingdom (UK), however data is fragmented. Through the presentation of three distinct but interconnecting studies this thesis aims to provide a comprehensive framework for documenting, quantifying, and understanding meteotsunami within the UK but with a view to global applicability, providing a valuable resource to aid in timely warnings and adaption measures vital for communities to be better prepared to face this natural hazard. The first study provides a standardised set of identification criteria and a comprehensive catalogue of 98 documented events between 1750 and 2022. The data showed pronounced geographical hotspots in Southern England and Northwest Scotland, with the prevalence of winter events associated with mid-latitude depressions and summer events associated with convective activity. This thereby challenges earlier assumptions about the seasonal and geographical distribution of meteotsunami in the UK. The second study introduces the Lewis Meteotsunami Intensity Index (LMTI), a new five-level framework aimed at creating a standardised methodology for quantifying meteotsunami intensity and impacts. The data revealed a 69% predominance of moderate intensity events (Level 2), with a spatial distribution of risk along the southern and western coasts. This trial of the LMTI serves as a prototype for global application, thus enhancing the understanding of meteotsunami in other susceptible regions. The final segment of this thesis investigates the potential disruption to saltmarsh vegetation from two UK meteotsunami (2016 and 2021). By utilising high-resolution satellite imagery and employing the Normalised Difference Vegetation Index (NDVI) data showed a minimal vegetation change (0.26 to 0.23) and a reduction in coverage of 40% in 2016 following an isolated event. However, in 2021 a reduction in NDVI (0.44 to 0.22) and a loss of 66% coverage occurred following a series of storms and meteotsunami.