Change search
Refine search result
45678910 121 - 140 of 335
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 121.
    Bergström, Sten
    et al.
    SMHI, Research Department, Hydrology.
    Lindström, Göran
    SMHI, Core Services.
    Interpretation of runoff processes in hydrological modelling experience from the HBV approach2015In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 29, no 16, p. 3535-3545Article in journal (Refereed)
    Abstract [en]

    The process of development and application of the Hydrologiska Byrans Vattenbalansavdelning hydrological model over a time period of more than 40years is reviewed and discussed. Emphasis is on the early modelling strategy and physical considerations based on contemporary research on runoff formation processes in the drainage basin. This includes areal considerations on the catchment scale, soil moisture and evapotranspiration and storages and discharge as represented by the response function of the model. The introduction of the concept of dynamic recharge and discharge areas is also addressed as well as the modelling of snow accumulation and melt. Some operational international experiences are also addressed. Copyright (c) 2015 John Wiley & Sons, Ltd.

  • 122.
    Andersson, Jafet
    et al.
    SMHI, Research Department, Hydrology.
    Pechlivanidis, Ilias
    SMHI, Research Department, Hydrology.
    Gustafsson, David
    SMHI, Research Department, Hydrology.
    Donnelly, Chantal
    SMHI, Research Department, Hydrology.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Key factors for improving large-scale hydrological model performance2015In: European Water, ISSN 1792-085X, Vol. 49, p. 77-88Article in journal (Refereed)
  • 123.
    Pechlivanidis, Ilias
    et al.
    SMHI, Research Department, Hydrology.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Large-scale hydrological modelling by using modified PUB recommendations: the India-HYPE case2015In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 19, no 11, p. 4559-4579Article in journal (Refereed)
    Abstract [en]

    The scientific initiative Prediction in Ungauged Basins (PUB) (2003-2012 by the IAHS) put considerable effort into improving the reliability of hydrological models to predict flow response in ungauged rivers. PUB's collective experience advanced hydrologic science and defined guidelines to make predictions in catchments without observed runoff data. At present, there is a raised interest in applying catchment models to large domains and large data samples in a multi-basin manner, to explore emerging spatial patterns or learn from comparative hydrology. However, such modelling involves additional sources of uncertainties caused by the inconsistency between input data sets, i.e. particularly regional and global databases. This may lead to inaccurate model parameterisation and erroneous process understanding. In order to bridge the gap between the best practices for flow predictions in single catchments and multi-basins at the large scale, we present a further developed and slightly modified version of the recommended best practices for PUB by Takeuchi et al. (2013). By using examples from a recent HYPE (Hydrological Predictions for the Environment) hydrological model set-up across 6000 subbasins for the Indian subcontinent, named India-HYPE v1.0, we explore the PUB recommendations, identify challenges and recommend ways to overcome them. We describe the work process related to (a) errors and inconsistencies in global databases, unknown human impacts, and poor data quality; (b) robust approaches to identify model parameters using a stepwise calibration approach, remote sensing data, expert knowledge, and catchment similarities; and (c) evaluation based on flow signatures and performance metrics, using both multiple criteria and multiple variables, and independent gauges for "blind tests". The results show that despite the strong physiographical gradient over the subcontinent, a single model can describe the spatial variability in dominant hydrological processes at the catchment scale. In addition, spatial model deficiencies are used to identify potential improvements of the model concept. Eventually, through simultaneous calibration using numerous gauges, the median Kling-Gupta efficiency for river flow increased from 0.14 to 0.64. We finally demonstrate the potential of multi-basin modelling for comparative hydrology using PUB, by grouping the 6000 subbasins based on similarities in flow signatures to gain insights into the spatial patterns of flow generating processes at the large scale.

  • 124.
    Berg, Peter
    et al.
    SMHI, Research Department, Hydrology.
    Bosshard, Thomas
    SMHI, Research Department, Hydrology.
    Yang, Wei
    SMHI, Research Department, Hydrology.
    Model Consistent Pseudo-Observations of Precipitation and Their Use for Bias Correcting Regional Climate Models2015In: CLIMATE, ISSN 2225-1154, Vol. 3, no 1, p. 118-132Article in journal (Refereed)
    Abstract [en]

    Lack of suitable observational data makes bias correction of high space and time resolution regional climate models (RCM) problematic. We present a method to construct pseudo-observational precipitation data by merging a large scale constrained RCM reanalysis downscaling simulation with coarse time and space resolution observations. The large scale constraint synchronizes the inner domain solution to the driving reanalysis model, such that the simulated weather is similar to observations on a monthly time scale. Monthly biases for each single month are corrected to the corresponding month of the observational data, and applied to the finer temporal resolution of the RCM. A low-pass filter is applied to the correction factors to retain the small spatial scale information of the RCM. The method is applied to a 12.5 km RCM simulation and proven successful in producing a reliable pseudo-observational data set. Furthermore, the constructed data set is applied as reference in a quantile mapping bias correction, and is proven skillful in retaining small scale information of the RCM, while still correcting the large scale spatial bias. The proposed method allows bias correction of high resolution model simulations without changing the fine scale spatial features, i.e., retaining the very information required by many impact models.

  • 125.
    Yang, Wei
    et al.
    SMHI, Research Department, Hydrology.
    Gardelin, Marie
    SMHI, Professional Services.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Bosshard, Thomas
    SMHI, Research Department, Hydrology.
    Multi-variable bias correction: application of forest fire risk in present and future climate in Sweden2015In: Natural hazards and earth system sciences, ISSN 1561-8633, E-ISSN 1684-9981, Vol. 15, no 9, p. 2037-2057Article in journal (Refereed)
    Abstract [en]

    As the risk of a forest fire is largely influenced by weather, evaluating its tendency under a changing climate becomes important for management and decision making. Currently, biases in climate models make it difficult to realistically estimate the future climate and consequent impact on fire risk. A distribution-based scaling (DBS) approach was developed as a post-processing tool that intends to correct systematic biases in climate modelling outputs. In this study, we used two projections, one driven by historical reanalysis (ERA40) and one from a global climate model (ECHAM5) for future projection, both having been dynamically down-scaled by a regional climate model (RCA3). The effects of the post-processing tool on relative humidity and wind speed were studied in addition to the primary variables precipitation and temperature. Finally, the Canadian Fire Weather Index system was used to evaluate the influence of changing meteorological conditions on the moisture content in fuel layers and the fire-spread risk. The forest fire risk results using DBS are proven to better reflect risk using observations than that using raw climate outputs. For future periods, southern Sweden is likely to have a higher fire risk than today, whereas northern Sweden will have a lower risk of forest fire.

  • 126. Hytteborn, Julia K.
    et al.
    Temnerud, Johan
    SMHI, Research Department, Hydrology.
    Alexander, Richard B.
    Boyer, Elizabeth W.
    Futter, Martyn N.
    Froberg, Mats
    Dahne, Joel
    SMHI, Professional Services.
    Bishop, Kevin H.
    Patterns and predictability in the intra-annual organic carbon variability across the boreal and hemiboreal landscape2015In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 520, p. 260-269Article in journal (Refereed)
    Abstract [en]

    Factors affecting total organic carbon (TOC) concentrations in 215 watercourses across Sweden were investigated using parameter parsimonious regression approaches to explain spatial and temporal variabilities of the TOC water quality responses. We systematically quantified the effects of discharge, seasonality, and long-term trend as factors controlling intra-annual (among year) and inter-annual (within year) variabilities of TOC by evaluating the spatial variability in model coefficients and catchment characteristics (e.g. land cover, retention time, soil type). Catchment area (0.18-47,000 km(2)) and land cover types (forests, agriculture and alpine terrain) are typical for the boreal and hemiboreal zones across Fennoscandia. Watercourses had at least 6 years of monthly water quality observations between 1990 and 2010. Statistically significant models (p < 0.05) describing variation of TOC in streamflow were identified in 209 of 215 watercourses with a mean Nash-Sutcliffe efficiency index of 0.44. Increasing long-term trends were observed in 149 (70%) of the watercourses, and intra-annual variation in TOC far exceeded inter-annual variation. The average influences of the discharge and seasonality terms on intra-annual variations in daily TOC concentration were 1.4 and 1.3 mg l(-1) (13 and 12% of the mean annual TOC), respectively. The average increase in TOC was 0.17 mg l(-1) year(-1) (1.6% year(-1)). Multivariate regression with over 90 different catchment characteristics explained 21% of the spatial variation in the linear trend coefficient, less than 20% of the variation in the discharge coefficient and 73% of the spatial variation in mean TOC. Specific discharge, water residence time, the variance of daily precipitation, and lake area, explained 45% of the spatial variation in the amplitude of the TOC seasonality. Because the main drivers of temporal variability in TOC are seasonality and discharge, first-order estimates of the influences of climatic variability and change on TOC concentration should be predictable if the studied catchments continue to respond similarly. (C) 2015 Elsevier B.V. All rights reserved.

  • 127.
    Olsson, Jonas
    et al.
    SMHI, Research Department, Hydrology.
    Simonsson, Lennart
    SMHI, Research Department, Hydrology.
    Ridal, Martin
    SMHI, Research Department, Meteorology.
    Rainfall nowcasting: predictability of short-term extremes in Sweden2015In: Urban Water Journal, ISSN 1573-062X, Vol. 12, no 1, p. 3-13Article in journal (Refereed)
    Abstract [en]

    Our current knowledge of the character of rainfall events in Sweden associated with extreme short-term accumulations and their predictability by forecasting, is very limited. In this study, observations from automatic stations and weather radars in Sweden were analysed to identify and characterise extreme short-term events. Often shorter-duration (1-6 h) extreme events were associated with small-scale structures, dominated by single cells, and longer-duration (12-24 h) events with less variable, larger-scale fields. For lead time 3 h, similar to 20% of the events were forecasted at the correct place with an error of <25% by the operational Swedish nowcasting system. If allowing for a 25 km displacement of the forecasted events, the hit rate increased by 10-15 percentage points. Some predictability was found for lead time 8 h but not for 24 h. The results suggest a potential added gain of increasing the temporal resolution of the Swedish flood forecasting system to sub-daily steps.

  • 128. Kayhko, Jukka
    et al.
    Apsite, Elga
    Bolek, Anna
    Filatov, Nikolai
    Kondratyev, Sergey
    Korhonen, Johanna
    Kriauciuniene, Jurate
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Nazarova, Larisa
    Pyrh, Anna
    Sztobryn, Marzenna
    Recent Change-River Run-off and Ice Cover2015Chapter in book (Other academic)
    Abstract [en]

    This chapter compiles and assesses information on run-off and discharge from rivers within the Baltic Sea drainage basin. Some information is also available on ice duration on inland waterways. Although decadal and regional variability is large, no significant long-term change has been detected in total river run-off to the Baltic Sea over the past 500 years. A change in the timing of the spring flood has been observed due to changes in the timing of snowmelt. Change in temperature seems to explain change in run-off better than does precipitation. Later start dates for ice formation on waterways, and earlier ice break-up dates have resulted in shorter periods of ice cover.

  • 129.
    Andersson, Lotta
    et al.
    SMHI, Research Department, Hydrology.
    Persson, Gunn
    SMHI, Professional Services.
    Bergström, Sten
    SMHI, Core Services.
    Ohlsson, Alexandra
    SMHI, Professional Services.
    Risker, konsekvenser och sårbarhet för samhället av förändrat klimat – en kunskapsöversikt: Flertalet av de i rapporten refererade myndigheterna och organisationerna har varit aktiva i framtagandet av texterna: Materialet har sammanställts av:2015Report (Other academic)
    Abstract [sv]

    Regeringen gav år 2014 SMHI i uppdrag att utarbeta underlag till Kontrollstation2015 för anpassning till ett förändrat klimat. Som en del av uppdraget ingick att göra en uppdaterad sammanställning av kunskapen om nuvarande och framtida risker och konsekvenser, främst med utgångspunkt från Klimat- och sårbarhetsutredningens slutbetänkande (SOU 2007:60). I föreliggande rapport beskrivs kunskapsläget kring det svenska samhällets sårbarhet för ett förändrat klimat. Klimatförändringarna påverkar hela samhället. Generellt kan sägas att medvetenheten om klimatförändringarnas påverkan har ökat, men det saknas en del kunskap och verktyg, främst på den lokala nivån. Översvämningsriskerna kring sjöar och längs vattendrag ökar, vilket kan påverka bebyggelse och infrastruktur. Risken för ras och skred tros också öka, främst i landets västra och sydvästra delar samt områden längs östra kusten. Erosion längs vattendrag, sjöar och kuster kan komma att öka i delar av landet. Vattentillgång och -kvalitet kommer att påverkas av förändrade nederbördsmönster, ökad spridning av föroreningar samt ökade mikrobiologiskarisker. Energisystemet kommer att utsättas för större påfrestningar, särskilt av extrema väderhändelser. Kunskapen har ökat kring klimatförändringarnas effekter på energisystemet, men det kvarstår kunskapsluckor relaterade till extremväder och anpassningsåtgärder. Kunskap och medvetenhet om klimatförändringarnas påverkan på kommunikationerna i samhället har ökat, men det finns fortfarande behov av mer utredning och verktyg. Förutsättningarna för jordbruket förbättras i huvudsak, med möjlighet till ökade skördar och nya grödor. Samtidigt kommer fler skadegörare och ogräs in. Nya behov av bevattning kan uppstå och markavvattningen kan behöva en översyn. Eventuellt minskat utbud av livsmedel på världsmarknaden, kan innebära ökad efterfrågan på svenska livsmedel. Samtidigt går Sverige idag mot ökat importberoende. Även djurhållningen står inför stora utmaningar. Å ena sidan kan djuren gå ute under en längre del av året och möjligheterna att vara självförsörjande med foder ökar. Men det varmare klimatet medför också risk för att nya djursjukdomar uppträder. Konsekvenserna för den svenska skogen och skogsbruket kommer att bli betydande. Ökad tillväxt ger större virkesproduktion, men ökad frekvens och omfattning av skador från främst insekter, svampar och storm samt blötare skogsmark kan föra med sig stora kostnader. Stora regionala skillnader i utbudet av kommersiellt virke kan påverka svensk skogsindustri. Förändrade förutsättningar är också att vänta för fiskbestånden. Nya fiskarter i svenska vatten kan föra med sig nya smittor och konkurrera ut befintliga arter i känsliga ekosystem. Renskötseln i Sverige kommer att allvarligt påverkas av klimatförändringarna och effekterna utgör stora utmaningar. Klimatförändringarna ger både positiva och negativa effekter för turismen. Det finns hinder för anpassningskapaciteten, bland annat bristande organisering av besöksnäringen. Människors och djurs hälsa kan påverkas direkt av extrema väderhändelser. Ett varmare klimat ger även upphov till förändrade smittspridningsmönster och nya sjukdomar kan nå Sverige. Förändringar i luft, vatten och mark, orsakade av klimatförändringar, kan också påverka hälsotillståndet för djur och människor. På nationell nivå är kunskaperna om risker för bebyggelse tillräckliga för att rekommendera åtgärder, men det saknas lokala beslutsunderlag. För kulturarvet behöver kunskapen öka. Klimatförändringarna förväntas leda till förändringar för den biologiska mångfalden och ekosystemen. Det påverkar förmågan att nå flera av Sveriges miljömål och behöver ses i samband med andra miljöhot. Det finns bland annat behov av regionala kartläggningar av hur arter, ekosystem, naturtyper och biologisk mångfald kan påverkas. Risk- och säkerhetsperspektivet har växt fram under senare år, men präglas av utmaningar avseende metoder. Mycket få studier behandlar förhållanden i Sverige.

  • 130. Pechlivanidis, G. I.
    et al.
    Keramaris, E.
    Pechlivanidis, Ilias
    SMHI, Research Department, Hydrology.
    Samaras, G. A.
    Shear stress estimation in the linear zone over impermeable and permeable beds in open channels2015In: Desalination and Water Treatment, ISSN 1944-3994, E-ISSN 1944-3986, Vol. 54, no 8, p. 2181-2189Article in journal (Refereed)
    Abstract [en]

    This paper investigates the shear stresses in the linear zone of open channel flows with permeable and impermeable bed. The permeable bed is simulated using a flexible vegetation of 2 cm thickness. Laboratory experiments were used for the calculation of the turbulent velocity profiles. The measurements were obtained using a two-dimensional (2D) particle image velocimetry (PIV). This optical method of fluid visualization is used to obtain instantaneous velocity measurements related properties in the fluids. The PIV method assumes that the particles of a fluid faithfully follow the flow dynamics; hence the motion of these seeding particles is used to calculate the dynamic characteristics of the flow. The measurements were conducted at a 12 x 10 cm(2) region located 4 m away from the channel's entrance, where the flow is considered fully developed. The uniformity of the flow was checked measuring the flow depth at two cross-sections (2 m distance between the two regions). The total discharge was estimated using a calibrated venture apparatus. Measurements of velocity were taken for the horizontal channel slope. Results showed that the type of bed can significantly influence the shear stress definition in the linear zone.

  • 131.
    Olsson, Jonas
    et al.
    SMHI, Research Department, Hydrology.
    Josefsson, Weine
    SMHI, Core Services.
    Skyfallsuppdraget ett regeringsuppdrag till SMHI2015Report (Other academic)
    Abstract [en]

    Arbetet har sammanfattats i en rapport, som kan betraktas som en lägesrapport, inkluderar en omvärldsanalys; vad som gjorts i Sverige och i andra länder, delvis inhämtat vid en expertworkshop. Rapporten innehåller också en bearbetning av SMHIs nederbördsobservationer avseende korttidsnederbörd (skyfall) och en diskussion kring olika statistiska metoder att analysera dessa observationer. Dessutom har SMHIs nuvarande system för att prognosera skyfall uppgraderats och i rapporten diskuteras även vilka möjligheter som finns att ytterligare förbättra prognoserna i framtiden. Den pågående klimatförändringen påverkar vädret och därmed skyfallen. Rapporten tar upp de senaste rönen inom forskningen och även de negativa effekter som skyfall ger på samhället. Vilka behov finns i samhället och vad kan vi göra för att minimera de negativa effekterna var något som diskuterades vid en användarworkshop.

  • 132. Falter, Daniela
    et al.
    Schroeter, Kai
    Dung, Nguyen Viet
    Vorogushyn, Sergiy
    Kreibich, Heidi
    Hundecha, Yeshewatesfa
    SMHI, Research Department, Hydrology.
    Apel, Heiko
    Merz, Bruno
    Spatially coherent flood risk assessment based on long-term continuous simulation with a coupled model chain2015In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 524, p. 182-193Article in journal (Refereed)
    Abstract [en]

    A novel approach for assessing flood risk in river catchments in a spatially consistent way is presented. The approach is based on a set of coupled models representing the complete flood risk chain, including a multisite, multivariate weather generator, a hydrological model, a coupled 1D-2D hydrodynamic model and a flood loss model. The approach is exemplarily developed for the meso-scale Mulde catchment in Germany. 10,000 years of meteorological fields at daily resolution are generated and used as input to the subsequent models, yielding 10,000 years of spatially consistent river discharge series, inundation patterns and damage values. This allows estimating flood risk directly from the simulated damage. The benefits of the presented approach are: (1) in contrast to traditional flood risk assessments, where homogenous return periods are assumed for the entire catchment, the approach delivers spatially heterogeneous patterns of precipitation, discharge, inundation and damage patterns which respect the spatial correlations of the different processes and their spatial interactions. (2) Catchment and floodplain processes are represented in a holistic way, since the complete chain of flood processes is represented by the coupled models. For instance, the effects of spatially varying antecedent catchment conditions on flood hydrographs are implicitly taken into account. (3) Flood risk is directly derived from damage yielding a more realistic representation of flood risk. Traditionally, the probability of discharge is used as proxy for the probability of damage. However, non-linearities and threshold behaviour along the flood risk chain contribute to substantial variability between damage probabilities and corresponding discharge probabilities. (C) 2015 Elsevier B.V. All rights reserved.

  • 133. Haerter, Jan O.
    et al.
    Eggert, Bastian
    Moseley, Christopher
    Piani, Claudio
    Berg, Peter
    SMHI, Research Department, Hydrology.
    Statistical precipitation bias correction of gridded model data using point measurements2015In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 42, no 6, p. 1919-1929Article in journal (Refereed)
    Abstract [en]

    It is well known that climate model output data cannot be used directly as input to impact models, e.g., hydrology models, due to climate model errors. Recently, it has become customary to apply statistical bias correction to achieve better statistical correspondence to observational data. As climate model output should be interpreted as the space-time average over a given model grid box and output time step, the status quo in bias correction is to employ matching gridded observational data to yield optimal results. Here we show that when gridded observational data are not available, statistical bias correction can be carried out using point measurements, e.g., rain gauges. Our nonparametric method, which we call scale-adapted statistical bias correction (SABC), is achieved by data aggregation of either the available modeled or gauge data. SABC is a straightforward application of the well-known Taylor hypothesis of frozen turbulence. Using climate model and rain gauge data, we show that SABC performs significantly better than equal-time period statistical bias correction.

  • 134.
    Eklund, Anna
    et al.
    SMHI, Core Services.
    Axén Mårtensson, Jenny
    SMHI, Core Services.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    Björck, Emil
    SMHI, Professional Services.
    Dahné, Joel
    SMHI, Professional Services.
    Lindström, Lena
    SMHI, Core Services.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Simonsson, Lennart
    SMHI, Research Department, Hydrology.
    Sjökvist, Elin
    SMHI, Professional Services.
    Sveriges framtida klimat: Underlag till Dricksvattenutredningen2015Report (Other academic)
    Abstract [en]

    The latest results from climate research have been used to produce detailed analyses of Sweden’s future climate. The results build on the climate scenarios that have been used by the UN’s climate panel in its Fifth Assessment Report (AR5). Two scenarios have been used in this analysis: RCP4.5, which significantly limits future emissions, and RCP8.5, which is a more conservative “business as usual” scenario. Calculations of the future climate and water availability are based on new material and some new conditions compared to analyses previously presented by SMHI. The calculated changes in precipitation, temperature, water availability and flooding are broadly the same as earlier reports. The use of the RCP8.5 scenario, with its high future concentration of greenhouse gases, strengthens the effects compared to previous analyses. Since the results of the UNs climate panel (AR5) were presented as late as 2013, the material produced by SMHI has involved intensive development. The results have required new methodologies and will continue to be evaluated by SMHI. Analyses have been made for a number of parameters that are relevant to the supply of drinking water. The table below summarises the results. Parameter Change Airtemperature Increasing in the whole country, in particular in northern Sweden, mainly during winter. Average precipitation Increasing in the whole country, in particular inland Norrland, mainly during winter and spring. Extreme short-term precipitation Increasing in the whole country, mainly for short-term heavy showers. Water availability Increasing in the whole country except for eastern Götaland. The increase is greatest during the winter. Decreasing during summer, in particular in eastern Götaland. 100-year floods and 200-year floods Increasing in large areas of the country. Decreasing in inland Norrland and the northern coast as well as north west Svealand. Low river flows Becoming more common in Götaland and Svealand, particularly in eastern Götaland. Sea levels Raised sea levels, with the greatest net rise in southern Sweden. Temperature Climate calculations show an increase in the mean annual temperature during the current century, but with a large spread of the result. The largest increase is calculated for the north, which is in agreement with earlier results from both SMHI and IPCC. The difference between the two emission scenarios is small for the period 2021-2050 but increases towards the end of the century. The RCP4.5 scenario implies an increase of around 3 degrees on average by 2100, compared to the period 1961-1990. The increase is greater for RCP8.5, giving an average of around 6 degrees by 2100. Precipitation Average precipitation is calculated to increase for the whole country in the future. The greatest increase is expected for inland Norrland. The difference between the two emission scenarios is small for the period 2021-2050 but increases by the end of the century. An increase is expected during all seasons, but mostly for winter and spring. Extreme short-term precipitation is calculated to become more intensive in a future climate. This applies particularly to short torrential showers. Water availability and flow In the future, an increase in water availability is expected in large parts of the country, particularly in northern Sweden and along the West Coast. Southern Sweden can instead expect a reduction which is due to increased evaporation. For large parts of the country the spring floods are expected to be lower and the winter floods will increase. The change in water availability differs between the seasons. During summer a decreasing in water availability is expected in large parts of the country, in particular in eastern Götaland. Extreme floods are expected to occur less often in inland Norrland, the northern coastal areas and for north western Svealand. In the rest of the country, extreme floods are expected to be more common. New calculations show that a larger part of Sweden’s area could be susceptible to stronger extreme floods compared to earlier calculations. In the future, more days with low river flows are expected in Götaland and large parts of Svealand. The greatest change is expected in eastern Götaland. This is a result of increased evaporation due to the rise in temperature. Sea level The global sea level is expected to rise in the future. A calculated upper limit for the increase has been put at about 1 m by the year 2100 according to the latest evaluation from IPCC. The land rise counteracts the rise in sea level, in particular for northern Sweden. Precipitation Average precipitation is calculated to increase for the whole country in the future. The greatest increase is expected for inland Norrland. The difference between the two emission scenarios is small for the period 2021-2050 but increases by the end of the century. An increase is expected during all seasons, but mostly for winter and spring. Extreme short-term precipitation is calculated to become more intensive in a future climate. This applies particularly to short torrential showers. Water availability and flow In the future, an increase in water availability is expected in large parts of the country, particularly in northern Sweden and along the West Coast. Southern Sweden can instead expect a reduction which is due to increased evaporation. For large parts of the country the spring floods are expected to be lower and the winter floods will increase. The change in water availability differs between the seasons. During summer a decreasing in water availability is expected in large parts of the country, in particular in eastern Götaland. Extreme floods are expected to occur less often in inland Norrland, the northern coastal areas and for north western Svealand. In the rest of the country, extreme floods are expected to be more common. New calculations show that a larger part of Sweden’s area could be susceptible to stronger extreme floods compared to earlier calculations. In the future, more days with low river flows are expected in Götaland and large parts of Svealand. The greatest change is expected in eastern Götaland. This is a result of increased evaporation due to the rise in temperature. Sea level The global sea level is expected to rise in the future. A calculated upper limit for the increase has been put at about 1 m by the year 2100 according to the latest evaluation from IPCC. The land rise counteracts the rise in sea level, in particular for northern Sweden.

  • 135. Eggert, B.
    et al.
    Berg, Peter
    SMHI, Research Department, Hydrology.
    Haerter, J. O.
    Jacob, D.
    Moseley, C.
    Temporal and spatial scaling impacts on extreme precipitation2015In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, no 10, p. 5957-5971Article in journal (Refereed)
    Abstract [en]

    Convective and stratiform precipitation events have fundamentally different physical causes. Using a radar composite over Germany, this study separates these precipitation types and compares extremes at different spatial and temporal scales, ranging from 1 to 50 km and 5 min to 6 h, respectively. Four main objectives are addressed. First, we investigate extreme precipitation intensities for convective and stratiform precipitation events at different spatial and temporal resolutions to identify type-dependent space and time reduction factors and to analyze regional and seasonal differences over Germany. We find strong differences between the types, with up to 30% higher reduction factors for convective compared to stratiform extremes, exceeding all other observed seasonal and regional differences within one type. Second, we investigate how the differences in reduction factors affect the contribution of each type to extreme events as a whole, again dependent on the scale and the threshold chosen. A clear shift occurs towards more convective extremes at higher resolution or higher percentiles. For horizontal resolutions of current climate model simulations, i.e., similar to 10 km, the temporal resolution of the data as well as the chosen threshold have profound influence on which type of extreme will be statistically dominant. Third, we compare the ratio of area to duration reduction factor for convective and stratiform events and find that convective events have lower effective advection velocities than stratiform events and are therefore more strongly affected by spatial than by temporal aggregation. Finally, we discuss the entire precipitation distribution regarding data aggregation and identify matching pairs of temporal and spatial resolutions where similar distributions are observed. The information is useful for planning observational networks or storing model data at different temporal and spatial scales.

  • 136.
    Andersson, Lotta
    et al.
    SMHI, Research Department, Hydrology.
    Bohman, Anna
    Linköpings universitet.
    van Well, Lisa
    Statens geotekniska institut.
    Jonsson, Anna
    Linköpings universitet.
    Persson, Gunn
    SMHI, Professional Services.
    Farelius, Johanna
    Enheten för samhällsekonomiska analyser vid Naturvårdsverket.
    Underlag till kontrollstation 2015 för anpassning till ett förändrat klimat2015Report (Other academic)
    Abstract [en]

    As the climate changes, actors on all levels and in all sectors will be affected. Thus it is imperative that authorities, municipalities, businesses and individual property owners all take action. Flooding, heat waves, landslides and erosion are only a few examples of the challenges that that society faces and needs to prepare for. Sweden must adapt to the impacts of a changing climate, as well as the indirect effects of climate change impacts in other parts of the world. The costs of adaptation can be high, but the European Commission, among others, has deemed that it still pays to adapt in relation to the costs incurred if no action is taken. Climate adaptation initiatives in Sweden have advanced significantly in recent years. Notable examples include governmental missions for a national elevation database, landslide risk mapping in the Göta Älv River Valley, the Swedish drinking water investigation, the County Administrative Boards’ regional climate change action plans, and the establishment of the National Knowledge Centre for Climate Adaptation. The Swedish Meteorological and Hydrological Institute’s mission to survey, analyse and follow-up on climate adaptation work in Sweden has shown that there is still a considerable need for further measures. This report provides proposals for a road map for climate adaptation in Sweden and concludes that climate adaptation is best conducted in a long-term manner, that roles and responsibilities should be made more transparent, and that better coordination among the many actors involved in climate adaptation is necessary. The most important conclusions for continued work are:  Laws and regulations need to be adapted; roles and responsibilities as well as strategies and goals should be made clearer.  Priority and funding should be given to research and development measures that fill an identified knowledge-gap, including long-term monitoring.  Knowledge and decision support as well as prognoses and warning systems should be more accessible.  There is a need to outline how the costs of adaptation should be distributed among actors and how resources for prioritised measures can be guaranteed. This mission has compiled knowledge of the current and future risks and consequences for society of a changing climate, such as effects on vital societal functions and human health. The mission has also surveyed the work that has been done since the publication of the final report of the Swedish Commission on Climate and Vulnerability in 2007. From this background material our goal has been to describe the gaps and challenges and provide suggestions for how adaptation can be approached in various sectors of society. The EU Strategy on Adaptation to Climate Change has been an important point of departure. The work has been performed in cooperation with national and regional authorities, municipalities, researchers, sectoral organisations and representatives of the private sector This report is comprised of a main report and 18 annexes. Chapter 3 of the main report is a synthesis of all of the proposals made throughout the document and as such can be seen as a road map to ensure that Sweden adapts to a changing climate.

  • 137. Malnes, E.
    et al.
    Buanes, A.
    Nagler, T.
    Bippus, G.
    Gustafsson, David
    SMHI, Research Department, Hydrology.
    Schiller, C.
    Metsamaki, S.
    Pulliainen, J.
    Luojus, K.
    Larsen, H. E.
    Solberg, R.
    Diamandi, A.
    Wiesmann, A.
    User requirements for the snow and land ice services - CryoLand2015In: The Cryosphere, ISSN 1994-0416, E-ISSN 1994-0424, Vol. 9, no 3, p. 1191-1202Article in journal (Refereed)
    Abstract [en]

    CryoLand (2011-2015) is a project carried out within the 7th Framework of the European Commission aimed at developing downstream services for monitoring seasonal snow, glaciers and lake/river ice primarily based on satellite remote sensing. The services target private and public users from a wide variety of application areas, and aim to develop sustainable services after the project is completed. The project has performed a thorough user requirement survey in order to derive targeted requirements for the service and provide recommendations for the design and priorities of the service. In this paper we describe the methods used, the major findings in this user survey, and how we used the results to design and specify the CryoLand snow and land ice service. The user requirement analysis shows that a European operational snow and land ice service is required and that there exists developed cryosphere products that can meet the specific needs. The majority of the users were mainly interested not only in the snow services, but also the lake/river ice products and the glacier products were desired.

  • 138.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    Utveckling och tillämpning av en digital avrinningsmodell2015Report (Other academic)
  • 139. Ceola, S.
    et al.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Baratti, E.
    Bloeschl, G.
    Capell, Réne
    SMHI, Research Department, Hydrology.
    Castellarin, A.
    Freer, J.
    Han, D.
    Hrachowitz, M.
    Hundecha, Yeshewatesfa
    SMHI, Research Department, Hydrology.
    Hutton, C.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Montanari, A.
    Nijzink, R.
    Parajka, J.
    Toth, E.
    Viglione, A.
    Wagener, T.
    Virtual laboratories: new opportunities for collaborative water science2015In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 19, no 4, p. 2101-2117Article in journal (Refereed)
    Abstract [en]

    Reproducibility and repeatability of experiments are the fundamental prerequisites that allow researchers to validate results and share hydrological knowledge, experience and expertise in the light of global water management problems. Virtual laboratories offer new opportunities to enable these prerequisites since they allow experimenters to share data, tools and pre-defined experimental procedures (i.e. protocols). Here we present the outcomes of a first collaborative numerical experiment undertaken by five different international research groups in a virtual laboratory to address the key issues of reproducibility and repeatability. Moving from the definition of accurate and detailed experimental protocols, a rainfall-runoff model was independently applied to 15 European catchments by the research groups and model results were collectively examined through a web-based discussion. We found that a detailed modelling protocol was crucial to ensure the comparability and reproducibility of the proposed experiment across groups. Our results suggest that sharing comprehensive and precise protocols and running the experiments within a controlled environment (e.g. virtual laboratory) is as fundamental as sharing data and tools for ensuring experiment repeatability and reproducibility across the broad scientific community and thus advancing hydrology in a more coherent way.

  • 140. Magnusson, Jan
    et al.
    Gustafsson, David
    SMHI, Research Department, Hydrology.
    Huesler, Fabia
    Jonas, Tobias
    Assimilation of point SWE data into a distributed snow cover model comparing two contrasting methods2014In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 50, no 10, p. 7816-7835Article in journal (Refereed)
    Abstract [en]

    In alpine and high-latitude regions, water resource decision making often requires large-scale estimates of snow amounts and melt rates. Such estimates are available through distributed snow models which in some situations can be improved by assimilation of remote sensing observations. However, in regions with frequent cloud cover, complex topography, or large snow amounts satellite observations may feature information of limited quality. In this study, we examine whether assimilation of snow water equivalent (SWE) data from ground observations can improve model simulations in a region largely lacking reliable remote sensing observations. We combine the model output with the point data using three-dimensional sequential data assimilation methods, the ensemble Kalman filter, and statistical interpolation. The filter performance was assessed by comparing the simulation results against observed SWE and snow-covered fraction. We find that a method which assimilates fluxes (snowfall and melt rates computed from SWE) showed higher model performance than a control simulation not utilizing the filter algorithms. However, an alternative approach for updating the model results using the SWE data directly did not show a significantly higher performance than the control simulation. The results show that three-dimensional data assimilation methods can be useful for transferring information from point snow observations to the distributed snow model. Key Points <list id="wrcr21142-list-0001" list-type="bulleted"> <list-item id="wrcr21142-li-0001">Evaluating methods for assimilating snow observations into distributed models <list-item id="wrcr21142-li-0002">Assimilation can improve model skill also at locations without observations <list-item id="wrcr21142-li-0003">Assimilation of fluxes appears more successful than assimilation of states <doi origin="wiley" registered="yes">10.1002/(ISSN)1944-7973</doi

45678910 121 - 140 of 335
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
v. 2.35.7
|