A century of sea level data and the UK's 2013/14 storm surges: an assessment of extremes and clustering using theNewlyn tide gauge record

[摘要] For the UK's longest and most complete sea level record (Newlyn), we assessextreme high waters and their temporal clustering; prompted by the 2013/2014winter of storms and flooding. These are set into context against thisalmost 100-year record. We define annual periods for which storm activityand high sea levels can be compared on a year-by-year basis. Amongst thestorms and high tides which affected Newlyn, the recent winter produced thelargest recorded high water level (3 February 2014) and five other highwater events above a 1 in 1-year return period. The large magnitude of tideand mean sea level, and the close inter-event spacings (of large returnperiod high waters), suggests that the 2013/2014 extreme high water level"season" can be considered the most extreme on record. However, storm andsea level events may be classified in different ways. For example, in thecontext of sea level rise (which we calculate linearly as 1.81 ± 0.1 mm yr⁻¹ from records between 1915 to 2014), a lower probabilitycombination of surge and tide occurred on 29 January 1948, whilst the 1995/1996 storm surge season saw the most high waters of ≥ the 1 in 1-year return period. We provide a basic categorisation of the four types ofextreme high water level cluster, ranging from consecutive tidal cycles tomultiple years. The assessment is extended to other UK sites (with shortersea level records and different tide-surge characteristics), which suggests2013/2014 was particularly unusual. Further work will assess clusteringmechanisms and flood system "memory".

[学科分类] 海洋学与技术