NVE Brage (Norges vassdrags- og energidirektorat)
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Present and future changes in winter climate indices relevant for access disruptions in Troms, northern Norway
Full text linkA number of seaside communities in Troms, northern Norway, are vulnerable to sudden weather-induced access disruptions due to high-impact weather and dependency on one or few roads. In this paper we study changes in winter weather known to potentially cause access disruptions in Troms, for the present climate (1958–2017) and two future periods (2041–2070; 2071–2100). We focus on climate indices associated with snow avalanches and weather that may lead to for example slippery road conditions. In two focus areas, the most important results show larger snow amounts now compared to 50 years ago, and heavy snowfall has become more intense and frequent. This trend is expected to turn in the future, particularly at low elevations where snow cover during winter might become a rarity by 2100. Strong snow drift, due to a combination of snowfall and wind speed, has slightly increased in the two focus areas, but a strong decrease is expected in the future due to less snow. Events of heavy rain during winter are rather infrequent in the present winter climate of Troms, but we show that these events are likely to occur much more often in all regions in the future
Spatial and temporal variation in Arctic freshwater chemistry—Reflecting climate‐induced landscape alterations and a changing template for biodiversity
Full text linkFreshwater chemistry across the circumpolar region was characterised using a pan‐Arctic data set from 1,032 lake and 482 river stations. Temporal trends were estimated for Early (1970–1985), Middle (1986–2000), and Late (2001–2015) periods. Spatial patterns were assessed using data collected since 2001.
Alkalinity, pH, conductivity, sulfate, chloride, sodium, calcium, and magnesium (major ions) were generally higher in the northern‐most Arctic regions than in the Near Arctic (southern‐most) region. In particular, spatial patterns in pH, alkalinity, calcium, and magnesium appeared to reflect underlying geology, with more alkaline waters in the High Arctic and Sub Arctic, where sedimentary bedrock dominated.
Carbon and nutrients displayed latitudinal trends, with lower levels of dissolved organic carbon (DOC), total nitrogen, and (to a lesser extent) total phosphorus (TP) in the High and Low Arctic than at lower latitudes. Significantly higher nutrient levels were observed in systems impacted by permafrost thaw slumps.
Bulk temporal trends indicated that TP was higher during the Late period in the High Arctic, whereas it was lower in the Near Arctic. In contrast, DOC and total nitrogen were both lower during the Late period in the High Arctic sites. Major ion concentrations were higher in the Near, Sub, and Low Arctic during the Late period, but the opposite bulk trend was found in the High Arctic.
Significant pan‐Arctic temporal trends were detected for all variables, with the most prevalent being negative TP trends in the Near and Sub Arctic, and positive trends in the High and Low Arctic (mean trends ranged from +0.57%/year in the High/Low Arctic to −2.2%/year in the Near Arctic), indicating widespread nutrient enrichment at higher latitudes and oligotrophication at lower latitudes.
The divergent P trends across regions may be explained by changes in deposition and climate, causing decreased catchment transport of P in the south (e.g. increased soil binding and trapping in terrestrial vegetation) and increased P availability in the north (deepening of the active layer of the permafrost and soil/sediment sloughing). Other changes in concentrations of major ions and DOC were consistent with projected effects of ongoing climate change. Given the ongoing warming across the Arctic, these region‐specific changes are likely to have even greater effects on Arctic water quality, biota, ecosystem function and services, and human well‐being in the future.Environment and Climate Change Canada
Cumulative Impact Monitoring Program, Government of Northwest Territorie
Styringssystem for omløpsventilar
Full text linkMed grunnlagsdata frå drift av fire små kraftverk er det laga eit generelt styringsverktøy for alle kraftverk med omløpsventil. Kravet er at vasstanden nedstraums kraftverket ikkje skal være raskare enn 10 cm/t. Denne rapporten presenterer valideringsforsøk på fire kraftverk av den teoretiske modellen. Resultata er gode der programmeringa er gjort korrekt og nytta grunnlagsdata er av god kvalitet
Effektiv kommunikasjon av naturfarevarsel fra NVE : hvordan kan NVE best formidle naturfarevarsler?
Full text linkProsjektet «Effektiv kommunikasjon av naturfarevarsel» ble gjennomført i regi av NVE i periode 2017-2018. Hovedmålet var å undersøke om naturfarevarslene blir forstått og utløser endret adferd hos brukerne av tre av våre varslingstjenester. Rapporten oppsummerer de viktigste funnene fra tre undersøkelser gjennomført i form av telefonintervju og nettundersøkelse. Vi har også samlet og gjennomgått internasjonale artikler om analyse av varselteksten, brukeradferd og risikokommunikasjon. 12 beredskapsansvarlige fra 12 kommuner spredt utover Vest, NordVest, Nord-Norge og Østlandet ble intervjuet på telefon og ble bedt å analysere tekstene av ulike flom-, jordskred- og snøskredvarsler. En nettundersøkelse ble brukt for å analysere snøskredvarsel, den involverte 200 snøskredeksperter og 485 brukere av snøskredvarse
Toppledermøtet i Naturfareforum 2019
Full text linkRapporten oppsummerer toppledermøtet i Naturfareforum i 2019 som tok for seg tre tema:
finansiering av forebygging, deling og tilgjengeliggjøring av data – juridisk grunnlag, og gode nasjonale løsninger knyttet til varsling av naturfar
New flood frequency estimates for the largest river in Norway based on the combination of short and long time series
Full text linkThe 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
Glaciological investigations in Norway 2019
Full text linkResults of glaciological investigations performed at Norwegian glaciers in 2019 are presented in this report. The main part concerns mass balance investigations. Results from investigations of glacier length changes are discussed in a separate chapter
Glacier outlines Nordland 1900
No full textArcGIS geodatabase containing Glacier Area Outlines (GAO) of all glaciers (n = 1587) in the northern Norwegian county of Nordland, including a small number of glaciers in the adjacent counties, in ca. 1900 (1882-1916).
Glacier outlines were digitised from georectified historical gradteigskart maps, published by Norges geografiske oppmåling (NGO; Norwegian Geographical Survey; now: Kartverket – Norwegian Mapping Authority).
These maps are based on field surveys carried out between 1882 and 1916.
The data set and the uncertainties associated with it are described in detail in Weber et al. (2020; Journal of Glaciology)
Uncertainty introduced by flood frequency analysis in projections for changes in flood magnitudes under a future climate in Norway
Full text linkStudy region: The study considers 115 unregulated catchments in Norway, with areas from 6 to 15,449 km2 and flood generation regimes ranging from snowmelt-dominated to ‘mixed’ (snow-melt and rainfall) to fully rainfall-driven.
Study focus: Bias-corrected EURO-CORDEX RCM output for RCP 8.5 is used to generate an ensemble of 500 hydrological simulations for assessing changes in flood magnitudes under a future climate. Flood estimates are based on three extreme value distributions (EVDs), Gumbel, Generalised Extreme Value and Generalised Pareto, with confidence intervals calculated using parametric bootstrapping, and uncertainty introduced into the ensemble by the flood estimation is evaluated using variance decomposition. Changes in EVD parameters under future conditions are also assessed.
New hydrologic insight for the region: There are large differences in projected changes between
catchments, with median estimates ranging from −48 % to +99 % for the 200 year flood. Flood
magnitudes in all catchments with rainfall-dominant or mixed flood regimes are expected to increase. EVDs with a shape parameter (GEV and GPD) indicate larger increases in higher flood quantiles than the Gumbel distribution (e.g. by 5–8 percentage points for the 200 year flood). Flood frequency estimation contributes 30–52 % of the total ensemble range in individual catchments. Location and scale parameters generally increase in catchments with increasing flood magnitudes, and some catchments with mixed flood regimes also exhibit increases in the shape parameter under future conditions
Ecological correlates of riverine diatom and macroinvertebrate alpha and beta diversity across Arctic Fennoscandia
Full text linkArctic freshwaters support biota adapted to the harsh conditions at these latitudes, but the climate is changing rapidly and so are the underlying environmental filters. Currently, we have limited understanding of broad‐scale patterns of Arctic riverine biodiversity and the correlates of α‐ and β‐diversity.
Using information from a database set up within the scope of the Arctic Council's Conservation of Arctic Flora and Fauna Circumpolar Biodiversity Monitoring Plan, we analysed patterns and correlates of α‐ and β‐diversity in benthic diatom and macroinvertebrate communities across northern Norway, Sweden, and Finland. We analysed variation in total β‐diversity and its replacement and richness difference components in relation to location of the river reach and its drainage basin (Baltic Sea in the south, the Barents Sea in the east and the north, and the Norwegian Sea in the west), in addition to climate and environmental variables.
In both macroinvertebrates and diatoms, the replacement and richness difference components showed wide variation. For macroinvertebrates, the richness difference component was the more important, whereas for diatoms, the replacement component was the more important in contributing to variation in β‐diversity. There was no significant difference in β‐diversity between the three main drainage basins, but species composition differed among the drainage basins.
Based on the richness difference component of β‐diversity, climate variables were most strongly associated with community variation in macroinvertebrates. In diatoms, both environmental and climate variables were strongly correlated with community compositional variation. In both groups, there were also significant differences in α‐diversity among the three main drainage basins, and several taxa were significant indicators of one of these drainage basins. Alpha diversity was greater in areas with a continental climate, while the oceanic areas in the west harboured greatly reduced flora and fauna.
The correlates of biodiversity were relatively similar in macroinvertebrates and diatoms. Climate variables, in particular temperature, were the most strongly associated with biodiversity patterns in the Arctic rivers of Fennoscandia. Sedimentary geology may be associated with increased productivity and, to a lesser extent, with sensitivity to acidification. There was considerable variation in community composition across Arctic Fennoscandia, indicating the necessity of protecting several stream reaches or even whole catchments within each region to conserve total riverine biodiversity. Furthermore, it is likely that the predicted changes in temperature in Arctic areas will influence riverine diversity patterns across Fennoscandia.Norwegian Water Resources & Energy Directorate
Norwegian Institute for Water Research
Ministry of Foreign Affairs, Finland
Norwegian Environmental Agenc