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标题：Meteotsunami occurrence in the Gulf of Finland over the past century
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作者：Pellikka, Havu ; Laurila, Terhi K. ; Boman, Hanna 等
期刊名称：Natural Hazards and Earth System Sciences
电子版ISSN：2195-9269
出版年度：2020
卷号：20
期号：9
页码：2535-2546
DOI：10.5194/nhess-20-2535-2020
语种：English
出版社：Copernicus Publications
摘要：We analyse changes in meteotsunami occurrence over the past century(1922–2014) in the Gulf of Finland, Baltic Sea. A major challenge forstudying these short-lived and local events is the limited temporaland spatial resolution of digital sea level and meteorologicaldata. To overcome this challenge, we examine archived paper recordingsfrom two tide gauges, Hanko for 1922–1989 and Hamina for 1928–1989,from the summer months of May–October. We visually inspect therecordings to detect rapid sea level variations, which are thendigitised and compared to air pressure observations from nearbystations. The data set is complemented with events detected fromdigital sea level data 1990–2014 by an automated algorithm. In total,we identify 121 potential meteotsunami events. Over 70 % ofthe events could be confirmed to have a rapid change in air pressureoccurring shortly before or simultaneously with the sea leveloscillations. The occurrence of meteotsunamis is strongly connectedwith lightning over the region: the number of cloud-to-ground (CG) flashesover the Gulf of Finland were on average over 10 times higher duringthe days when a meteotsunami was recorded compared to days with nometeotsunamis in May–October. On a monthly level, statisticallysignificant differences between meteotsunami months and other monthswere found in the number of CG flashes, convective available potentialenergy (CAPE), and temperature. Meteotsunami occurrence over the pastcentury shows a statistically significant increasing trend in Hamina,but not in Hanko.