TY - JOUR

T1 - Improvements to the detection and analysis of external surges in the North Sea

AU - Böhme, Alexander

AU - Gerkensmeier, Birgit

AU - Bratz, Benedikt

AU - Krautwald, Clemens

AU - Müller, Olaf

AU - Goseberg, Nils

AU - Gönnert, Gabriele

N1 - Funding Information: BG, GG and NG conceptualized the study. GG and AM developed and improved the methodology. AM implemented the code and curated the data. The investigation was conducted by AM and BG and formal analysis by AM, BB and CK. AM wrote the original draft, which was edited by BB, BG, CK, GG, NG and OM. GG and NG supervised the project. NG provided a share of funding through a start-up grant of the Technische Universität Braunschweig.

PY - 2023/5/26

Y1 - 2023/5/26

N2 - External surges are a key component of extreme water levels in the North Sea. Caused by low-pressure cells over the North Atlantic and amplified at the continental shelf, they can drive water-level changes of more than 1m at the British, Dutch and German coasts. This work describes an improved and semi-automated method to detect external surges in sea surface time histories. The method is used to analyse tide gauge and meteorological records from 1995 to 2020 and to supplement an existing dataset of external surges, which is used in the determination of design heights of coastal protection facilities. Furthermore, external surges are analysed with regard to their annual and decadal variability, corresponding weather conditions, and their interaction with storm surges in the North Sea. A total of 33% of the 101 external surges occur within close succession of each other, leading to the definition of serial external surges, in which one or more external surges follow less than 72h after the previous external surge. These serial events tend to occur more often during wind-induced storm surges. Moreover, the co-occurrence with a storm surge increases the height of an external surge by 15% on average, highlighting the importance of the consideration of combined events in coastal protection strategies. The improved dataset and knowledge about serial external surges extend the available basis for coastal protection in the North Sea region.

AB - External surges are a key component of extreme water levels in the North Sea. Caused by low-pressure cells over the North Atlantic and amplified at the continental shelf, they can drive water-level changes of more than 1m at the British, Dutch and German coasts. This work describes an improved and semi-automated method to detect external surges in sea surface time histories. The method is used to analyse tide gauge and meteorological records from 1995 to 2020 and to supplement an existing dataset of external surges, which is used in the determination of design heights of coastal protection facilities. Furthermore, external surges are analysed with regard to their annual and decadal variability, corresponding weather conditions, and their interaction with storm surges in the North Sea. A total of 33% of the 101 external surges occur within close succession of each other, leading to the definition of serial external surges, in which one or more external surges follow less than 72h after the previous external surge. These serial events tend to occur more often during wind-induced storm surges. Moreover, the co-occurrence with a storm surge increases the height of an external surge by 15% on average, highlighting the importance of the consideration of combined events in coastal protection strategies. The improved dataset and knowledge about serial external surges extend the available basis for coastal protection in the North Sea region.

UR - http://www.scopus.com/inward/record.url?scp=85163669994&partnerID=8YFLogxK

U2 - 10.5194/nhess-23-1947-2023

DO - 10.5194/nhess-23-1947-2023

M3 - Article

AN - SCOPUS:85163669994

VL - 23

SP - 1947

EP - 1966

JO - Natural Hazards and Earth System Sciences

JF - Natural Hazards and Earth System Sciences

SN - 1561-8633

IS - 5

ER -