Linking large-scale climate oscillations to local wave climate and storm surge: insights from a weather typing approach

Abstract. Understanding temporal variations in nearshore sea states is crucial, as they affect shoreline evolution and coastal hazard potential. Local sea state conditions are influenced by daily synoptic weather patterns and by large-scale climate oscillations. Although the underlying mechanisms remain not fully understood, numerous studies have established the links between interannual climate patterns and local sea state variability. While most existing research has relied on correlation analyses or other statistical methods, this study explores the possibility of using a weather typing approach to relate climate oscillation patterns to local wave climate and storm surge. The analysis was conducted at Hartlepool, UK, where 36 weather types were previously developed to assess the exposure to coastal hazards for a local nuclear power station. Six climate indices were examined, and we found that the North Atlantic Oscillation (NAO) and the Scandinavian pattern (SCAND) have significant correlations with local wave and storm surge variables. The weather type analysis reveals that, in response to the phases of NAO or SCAND, storm surge distributions exhibit changes in the mean and standard deviation, peak wave period distributions shift between bimodal and near-unimodal shapes, and wind waves and swell show different dominant directions. These response patterns are attributable to the impacts of atmospheric pressure, wind forcing, and extratropical storm frequency, which are modulated by large-scale climate dynamics associated with NAO and SCAND. This research demonstrates the potential of weather types to offer new perspectives into the impact of climate oscillations on local sea states.