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dc.contributor.authorEngeland, Kolbjørn
dc.contributor.authorAano, Anna
dc.contributor.authorSteffensen, Ida Grøndahl
dc.contributor.authorStøren, Eivind Wilhelm Nagel
dc.contributor.authorPaasche, Øyvind
dc.date.accessioned2021-05-18T07:53:48Z
dc.date.available2021-05-18T07:53:48Z
dc.date.created2020-12-18T11:26:35Z
dc.date.issued2020
dc.PublishedHydrology and Earth System Sciences. 2020, 24 (11), 5595-5619.
dc.identifier.issn1027-5606
dc.identifier.urihttps://hdl.handle.net/11250/2755353
dc.description.abstractThe Glomma River is the largest in Norway, with a catchment area of 154 450 km2. People living near the shores of this river are frequently exposed to destructive floods that impair local cities and communities. Unfortunately, design flood predictions are hampered by uncertainty since the standard flood records are much shorter than the requested return period and the climate is also expected to change in the coming decades. Here we combine systematic historical and paleo information in an effort to improve flood frequency analysis and better understand potential linkages to both climate and non-climatic forcing. Specifically, we (i) compile historical flood data from the existing literature, (ii) produce high-resolution X-ray fluorescence (XRF), magnetic susceptibility (MS), and computed tomography (CT) scanning data from a sediment core covering the last 10 300 years, and (iii) integrate these data sets in order to better estimate design floods and assess non-stationarities. Based on observations from Lake Flyginnsjøen, receiving sediments from Glomma only when it reaches a certain threshold, we can estimate flood frequency in a moving window of 50 years across millennia revealing that past flood frequency is non-stationary on different timescales. We observe that periods with increased flood activity (4000–2000 years ago and <1000 years ago) correspond broadly to intervals with lower than average summer temperatures and glacier growth, whereas intervals with higher than average summer temperatures and receding glaciers overlap with periods of reduced numbers of floods (10 000 to 4000 years ago and 2200 to 1000 years ago). The flood frequency shows significant non-stationarities within periods with increased flood activity, as was the case for the 18th century, including the 1789 CE (“Stor-Ofsen”) flood, the largest on record for the last 10 300 years at this site. Using the identified non-stationarities in the paleoflood record allowed us to estimate non-stationary design floods. In particular, we found that the design flood was 23 % higher during the 18th century than today and that long-term trends in flood variability are intrinsically linked to the availability of snow in late spring linking climate change to adjustments in flood frequency.en_US
dc.language.isoengen_US
dc.publisherCopernicus Publicationsen_US
dc.rightsNavngivelse 4.0 Internasjonal*
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/deed.no*
dc.titleNew flood frequency estimates for the largest river in Norway based on the combination of short and long time seriesen_US
dc.typeJournal articleen_US
dc.typePeer revieweden_US
dc.description.versionpublishedVersionen_US
dc.rights.holderCopyright Author(s) 2020.en_US
cristin.ispublishedtrue
cristin.fulltextoriginal
cristin.fulltextoriginal
cristin.qualitycode2
dc.identifier.doi10.5194/hess-24-5595-2020
dc.identifier.cristin1861502
dc.source.journalHydrology and Earth System Sciencesen_US
dc.source.4024
dc.source.1411
dc.source.pagenumber5595-5619en_US
dc.relation.projectNorges forskningsråd: 812957en_US
dc.relation.projectRegionale forskningsfond Vestlandet: 269682en_US
dc.relation.projectNorges forskningsråd: 226171en_US
dc.identifier.citationHydrology and Earth System Sciences. 2020, 24 (11), 5595-5619.en_US
dc.source.volume24en_US
dc.source.issue11en_US


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Navngivelse 4.0 Internasjonal
Except where otherwise noted, this item's license is described as Navngivelse 4.0 Internasjonal