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  • 151.
    Bennet, Cecilia
    et al.
    SMHI, Research Department, Air quality.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    A regional model for surface ozone in Southeast Asia2008In: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 60, no 5, p. 718-728Article in journal (Refereed)
    Abstract [en]

    As part of the model intercomparison study MICS Asia II, the Swedish MATCH model was set up for Southeast and East Asia. In that study, the comprehensive photochemistry scheme of MATCH was used for the first time in Asia. The current work focuses on results of surface ozone from the MATCH model simulations falling outside the model intercomparison study. Model results of surface ozone concentrations for the entire year of 2001 were investigated and compared with measurements in Southeast Asia. The model produced higher surface ozone concentrations than the observations at all of the non-remote stations investigated but underestimated during the dry season at remote locations. Modelled seasonal variation was similar to, but less pronounced than, the variation in the measurements. This study indicates that NO(x) is the limiting precursor for ozone production in the model, while the fractionation in different species and total amount of non-methane volatile organic compounds (NMVOC) emissions are less important. Naturally emitted NMVOC, isoprene, is an important precursor of surface ozone at certain conditions, and a better inventory of these emissions is needed. Deposition velocities of ozone also have impact on surface concentrations. To improve the model performance, it is important to add a land use inventory with corresponding deposition velocities.

  • 152.
    Bennet, Cecilia
    et al.
    SMHI, Research Department, Air quality.
    Jonsson, P
    Lindgren, E S
    Concentrations and sources of trace elements in particulate air pollution, Dar es Salaam, Tanzania, studied by EDXRF2005In: X-Ray Spectrometry, ISSN 0049-8246, E-ISSN 1097-4539, Vol. 34, no 1, p. 1-6Article in journal (Refereed)
    Abstract [en]

    Trace elements in near-ground atmospheric aerosols were investigated in Dar es Salaam, Tanzania. Particles were collected at two sites, one urban and one rural, during, two months with different meteorological conditions. The samplers, dichotomous impactors, segregate the particles into two size fractions, fine (PM2.5, d(a) < 2.5 mum) and coarse (2.5 < d(a) < 10 mum). A sharp cyclone was used to sample finer particles (PM1, d(a) < 1 mum). Meteorological parameters were also examined at both sites. An EDXRF spectrometer, based on three-axial geometry, was used for quantitative elemental analysis. Concentrations of elements heavier than phosphorus were determined. Also, the content of black carbon on the filters was measured with a reflectometer. The elemental concentrations were compared with respect to season and geographical location in the city. The levels of different species in Dar es Salaam were also compared with similar data from other African and European countries. This showed low values of Pb with respect to the size of the city and no legislation on the use of leaded petrol, that often is the main source of lead. High values of Cl were also found, as would be expected in a coastal city. The coarse particles in the air, originating from soil, had a different composition in Dar es Salaam than in Gaborone, Botswana, and the concentration of black carbon was higher than in other cities. On the basis of the data collected, source assignments were made and the following sources found; sea-spray, soil, city road dust, biomass burning industries and traffic. Comparing the concentrations of different elements in PM2.5 and PM1 revealed that black carbon, Zn, Pb, K and Br are present only in the smallest particles. Copyright (C) 2005 John Wiley Sons, Ltd.

  • 153. Berdalet, Elisa
    et al.
    Kudela, Raphael
    Urban, Ed
    Enevoldsen, Henrik
    Banas, Neil S.
    Bresnan, Eileen
    Burford, Michele
    Davidson, Keith
    Gobler, Christopher J.
    Karlson, Bengt
    SMHI, Research Department, Oceanography.
    Lim, Po Teen
    Mackenzie, Lincoln
    Montresor, Marina
    Trainer, Vera L.
    Usup, Gires
    Yin, Kedong
    GlobalHAB A New Program to Promote International Research, Observations, and Modeling of Harmful Algal Blooms in Aquatic Systems2017In: Oceanography, ISSN 1042-8275, Vol. 30, no 1, p. 70-81Article in journal (Refereed)
  • 154.
    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.

  • 155.
    Berg, Peter
    et al.
    SMHI, Research Department, Hydrology.
    Christensen, Ole B.
    Klehmet, Katharina
    SMHI, Research Department, Hydrology.
    Lenderink, Geert
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Teichmann, Claas
    Yang, Wei
    SMHI, Research Department, Hydrology.
    Summertime precipitation extremes in a EURO-CORDEX 0.11 degrees ensemble at an hourly resolution2019In: Natural hazards and earth system sciences, ISSN 1561-8633, E-ISSN 1684-9981, Vol. 19, no 4, p. 957-971Article in journal (Refereed)
  • 156.
    Berg, Peter
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Doescher, Ralf
    SMHI, Research Department, Climate research - Rossby Centre.
    Koenigk, Torben
    SMHI, Research Department, Climate research - Rossby Centre.
    Impacts of using spectral nudging on regional climate model RCA4 simulations of the Arctic2013In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 6, no 3, p. 849-859Article in journal (Refereed)
    Abstract [en]

    The performance of the Rossby Centre regional climate model RCA4 is investigated for the Arctic CORDEX (COordinated Regional climate Downscaling EXperiment) region, with an emphasis on its suitability to be coupled to a regional ocean and sea ice model. Large biases in mean sea level pressure (MSLP) are identified, with pronounced too-high pressure centred over the North Pole in summer of over 5 hPa, and too-low pressure in winter of a similar magnitude. These lead to biases in the surface winds, which will potentially lead to strong sea ice biases in a future coupled system. The large-scale circulation is believed to be the major reason for the biases, and an implementation of spectral nudging is applied to remedy the problems by constraining the large-scale components of the driving fields within the interior domain. It is found that the spectral nudging generally corrects for the MSLP and wind biases, while not significantly affecting other variables, such as surface radiative components, two-metre temperature and precipitation.

  • 157.
    Berg, Peter
    et al.
    SMHI, Research Department, Hydrology.
    Doescher, Ralf
    SMHI, Research Department, Climate research - Rossby Centre.
    Koenigk, Torben
    SMHI, Research Department, Climate research - Rossby Centre.
    On the effects of constraining atmospheric circulation in a coupled atmosphere-ocean Arctic regional climate model2016In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 46, no 11-12, p. 3499-3515Article in journal (Refereed)
  • 158.
    Berg, Peter
    et al.
    SMHI, Research Department, Hydrology.
    Donnelly, Chantal
    SMHI, Research Department, Hydrology.
    Gustafsson, David
    SMHI, Research Department, Hydrology.
    Near-real-time adjusted reanalysis forcing data for hydrology2018In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 22, no 2, p. 989-1000Article in journal (Refereed)
  • 159.
    Berg, Peter
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Feldmann, H.
    Panitz, H. -J
    Bias correction of high resolution regional climate model data2012In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 448, p. 80-92Article in journal (Refereed)
    Abstract [en]

    Bias correction of varying complexity - from simple scaling and additive corrections to more advanced histogram equalisation (HE) corrections - is applied to high resolution (7 km) regional climate model (RCM) simulations. The aim of the study is to compare different methods that are easily implemented and applied to the data, and to assess the applicability and impact of the bias correction depending on the type of bias. The model bias is determined by comparison to a new gridded high resolution (1 km) data set of temperature and precipitation, which is also used as reference for the corrections. The performance of the different methods depends on the type of bias of the model, and on the investigated statistic. Whereas simpler methods correct the first moment of the distributions, they can have adverse effects on higher moments. The HE method corrects also higher moments, but approximations of the transfer function are necessary when applying the method to other data than the calibration data. Here, an empirical transfer function with linear fits to the tails is compared to a version where the complete function is approximated by a linear fit. The latter is thus limited to corrections of the first and second moments of the distribution. While making the transfer function more generally applicable, these approximations also limit the performance of the HE method. For the current model biases, the linear approximation is found suitable for precipitation, but for temperature it is not able to correct the whole distribution. The lower performance of the linear correction is most pronounced in summer, and is likely due to a difference in skewness between the model and observational data. Further limitations of the HE method are due to the need for long time series in order to have robust distributions for calculating the transfer function. Theoretical approximations of the required length of the calibration period were performed by using different sampling sizes drawn from a known distribution. The excerise show that about 30 year long time series are needed to have reasonable accuracy for the estimation of variance, when also corrections of the annual cycle is required. (C) 2012 Elsevier B.V. All rights reserved.

  • 160.
    Berg, Peter
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Moseley, Christopher
    Haerter, Jan O.
    Strong increase in convective precipitation in response to higher temperatures2013In: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 6, no 3, p. 181-185Article in journal (Refereed)
    Abstract [en]

    Precipitation changes can affect society more directly than variations in most other meteorological observables(1-3), but precipitation is difficult to characterize because of fluctuations on nearly all temporal and spatial scales. In addition, the intensity of extreme precipitation rises markedly at higher temperature(4-9), faster than the rate of increase in the atmosphere's water-holding capacity(1,4), termed the Clausius-Clapeyron rate. Invigoration of convective precipitation (such as thunderstorms) has been favoured over a rise in strati-form precipitation (such as large-scale frontal precipitation) as a cause for this increase(4,10), but the relative contributions of these two types of precipitation have been difficult to disentangle. Here we combine large data sets from radar measurements and rain gauges over Germany with corresponding synoptic observations and temperature records, and separate convective and stratiform precipitation events by cloud observations. We find that for stratiform precipitation, extremes increase with temperature at approximately the Clausius-Clapeyron rate, without characteristic scales. In contrast, convective precipitation exhibits characteristic spatial and temporal scales, and its intensity in response to warming exceeds the Clausius-Clapeyron rate. We conclude that convective precipitation responds much more sensitively to temperature increases than stratiform precipitation, and increasingly dominates events of extreme precipitation.

  • 161.
    Berg, Peter
    et al.
    SMHI, Research Department, Hydrology.
    Norin, Lars
    SMHI, Research Department, Atmospheric remote sensing.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Creation of a high resolution precipitation data set by merging gridded gauge data and radar observations for Sweden2016In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 541, p. 6-13Article in journal (Refereed)
  • 162.
    Berg, Peter
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Wagner, Sven
    Kunstmann, Harald
    Schaedler, Gerd
    High resolution regional climate model simulations for Germany: part I-validation2013In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 40, no 1-2, p. 401-414Article in journal (Refereed)
    Abstract [en]

    A five-member ensemble of regional climate model (RCM) simulations for Europe, with a high resolution nest over Germany, is analysed in a two-part paper: Part I (the current paper) presents the performance of the models for the control period, and Part II presents results for near future climate changes. Two different RCMs, CLM and WRF, were used to dynamically downscale simulations with the ECHAM5 and CCCma3 global climate models (GCMs), as well as the ERA40-reanalysis for validation purposes. Three realisations of ECHAM5 and one with CCCma3 were downscaled with CLM, and additionally one realisation of ECHAM5 with WRF. An approach of double nesting was used, first to an approximately 50 km resolution for entire Europe and then to a domain of approximately 7 km covering Germany and its near surroundings. Comparisons of the fine nest simulations are made to earlier high resolution simulations for the region with the RCM REMO for two ECHAM5 realisations. Biases from the GCMs are generally carried over to the RCMs, which can then reduce or worsen the biases. The bias of the coarse nest is carried over to the fine nest but does not change in amplitude, i.e. the fine nest does not add additional mean bias to the simulations. The spatial pattern of the wet bias over central Europe is similar for all CLM simulations, and leads to a stronger bias in the fine nest simulations compared to that of WRF and REMO. The wet bias in the CLM model is found to be due to a too frequent drizzle, but for higher intensities the distributions are well simulated with both CLM and WRF at the 50 and 7 km resolutions. Also the spatial distributions are close to high resolution gridded observations. The REMO model has low biases in the domain averages over Germany and no drizzle problem, but has a shift in the mean precipitation patterns and a strong overestimation of higher intensities. The GCMs perform well in simulating the intensity distribution of precipitation at their own resolution, but the RCMs add value to the distributions when compared to observations at the fine nest resolution.

  • 163.
    Bergstrand, Marie
    et al.
    SMHI, Core Services.
    Asp, Sara-Sofia
    SMHI, Core Services.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Nationwide hydrological statistics for Sweden with high resolution using the hydrological model S-HYPE2014In: HYDROLOGY RESEARCH, ISSN 1998-9563, Vol. 45, no 3, p. 349-356Article in journal (Refereed)
    Abstract [en]

    A first version of nationally covering hydrological statistics for Sweden based on the S-HYPE hydrological model for the period 1961-2010 is described. A key feature of the proposed method is that observed data are used as input wherever such data are available, and the model is used for interpolation in between stations. Short observation records are automatically extended by the use of the model. High flow statistics typically differed by about +/- 10% from observations. The corresponding number for low flow was about +/- 30%. High flow peaks were usually simulated slightly too low whereas low flows were too high. In a relative sense low flows were more uncertain than high flows. The mean flow was relatively certain. The annual maximum values were fitted to a Gumbel distribution, by the method of moments, for each subbasin. Flood statistics were then calculated up to a return period of 50 years. According to a Kolmogorov-Smirnov test, less than 1% of the fitted distributions were rejected. Most rejections occurred in regulated systems, due to difficulties in simulating regulation strategies, but also due to uncertainties in the precipitation input in the mountainous region. Results at small scale are very uncertain. The proposed method is a cost-effective way of calculating hydrological statistics with high spatial resolution.

  • 164.
    Bergström, Robert
    et al.
    SMHI, Research Department, Air quality.
    Hallquist, M.
    Simpson, D.
    Wildt, J.
    Mentel, T. F.
    Biotic stress: a significant contributor to organic aerosol in Europe?2014In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 14, no 24, p. 13643-13660Article in journal (Refereed)
    Abstract [en]

    We have investigated the potential impact on organic aerosol formation from biotic stress-induced emissions (SIE) of organic molecules from forests in Europe (north of lat. 45 degrees N). Emission estimates for sesquiterpenes (SQT), methyl salicylate (MeSA) and unsaturated C-17 compounds, due to different stressors, are based on experiments in the Julich Plant Atmosphere Chamber (JPAC), combined with estimates of the fraction of stressed trees in Europe based on reported observed tree damage. SIE were introduced in the EMEP MSC-W chemical transport model and secondary organic aerosol (SOA) yields from the SIE were taken from the JPAC experiments. Based on estimates of current levels of infestation and the JPAC aerosol yields, the model results suggest that the contribution to SOA in large parts of Europe may be substantial. It is possible that SIE contributes as much, or more, to organic aerosol than the constitutive biogenic VOC emissions, at least during some periods. Based on the assumptions in this study, SIE-SOA are estimated to constitute between 50 and 70% of the total biogenic SOA (BSOA) in a current-situation scenario where the biotic stress in northern and central European forests causes large SIE of MeSA and SQT. An alternative current-situation scenario with lower SIE, consisting solely of SQT, leads to lower SIE-SOA, between 20 and 40% of the total BSOA. Hypothetical future scenarios with increased SIE, due to higher degrees of biotic stress, show that SOA formation due to SIE can become even larger. Unsaturated C17 BVOC (biogenic volatile organic compounds) emitted by spruce infested by the forest-honey generating bark louse, Cinara pilicornis, have a high SOA-forming potential. A model scenario investigating the effect of a regional, episodic infestation of Cinara pilicornis in Baden-Wurttemberg, corresponding to a year with high production of forest honey, shows that these types of events could lead to very large organic aerosol formation in the infested region. We have used the best available laboratory data on biotic SIE applicable to northern and central European forests. Using these data and associated assumptions, we have shown that SIE are potentially important for SOA formation but the magnitude of the impact is uncertain and needs to be constrained by further laboratory, field and modelling studies. As an example, the MeSA, which is released as a consequence of various types of biotic stress, is found to have a potentially large impact on SIE-SOA in Europe, but different assumptions regarding the nighttime chemistry of MeSA can change its SOA potential substantially. Thus, further investigations of the atmospheric chemistry of MeSA and observational field studies are needed to clarify the role of this compound in the atmosphere.

  • 165.
    Bergström, Robert
    et al.
    SMHI, Research Department, Air quality.
    van der Gon, H. A. C. Denier
    Prevot, A. S. H.
    Yttri, K. E.
    Simpson, D.
    Modelling of organic aerosols over Europe (2002-2007) using a volatility basis set (VBS) framework: application of different assumptions regarding the formation of secondary organic aerosol2012In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 12, no 18, p. 8499-8527Article in journal (Refereed)
    Abstract [en]

    A new organic aerosol module has been implemented into the EMEP chemical transport model. Four different volatility basis set (VBS) schemes have been tested in long-term simulations for Europe, covering the six years 2002-2007. Different assumptions regarding partitioning of primary organic aerosol and aging of primary semi-volatile and intermediate volatility organic carbon (S/IVOC) species and secondary organic aerosol (SOA) have been explored. Model results are compared to filter measurements, aerosol mass spectrometry (AMS) data and source apportionment studies, as well as to other model studies. The present study indicates that many different sources contribute significantly to organic aerosol in Europe. Biogenic and anthropogenic SOA, residential wood combustion and vegetation fire emissions may all contribute more than 10% each over substantial parts of Europe. This study shows smaller contributions from biogenic SOA to organic aerosol in Europe than earlier work, but relatively greater anthropogenic SOA. Simple VBS based organic aerosol models can give reasonably good results for summer conditions but more observational studies are needed to constrain the VBS parameterisations and to help improve emission inventories. The volatility distribution of primary emissions is one important issue for further work. Emissions of volatile organic compounds from biogenic sources are also highly uncertain and need further validation. We can not reproduce winter levels of organic aerosol in Europe, and there are many indications that the present emission inventories substantially underestimate emissions from residential wood combustion in large parts of Europe.

  • 166.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    Parametervärden för HBV-modellen i Sverige: Erfarenheter från modellkalibreringar under perioden 1975-19891990Report (Other academic)
    Abstract [sv]

    HBV-modellen utvecklades vid SMHI i början av 1970-talet och har sedan dess funnit ett stort antal tillämpningar i landet. Inledningsvis var intresset mest knutet till hydrologisk prognosering åt vattenkraftindustrin och översvämningsvarningar till allmänheten, men under senare år har modellen fått spela en allt större roll för beräkning av dimensionerande flöden. Modellen finns i ett antal versioner, HBV-3, HBV-6 och HBV-TL samt ytterligare några för speciella tillämpningar. Dessutom finns ett antal versioner av modellen vid institutioner utanför SMHI såväl i Sverigesom utomlands.

  • 167.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    PRINCIPLES AND CONFIDENCE IN HYDROLOGICAL MODELING1991In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 22, no 2, p. 123-136Article in journal (Refereed)
    Abstract [en]

    General principles in development and application of hydrological models are discussed and related to the confidence in the results. The presentation is mainly based on the experience from the work with the HBV and PULSE models at the Swedish Meteorological and Hydrological Institute between 1971 and 1990 but has also been influenced by other modelling work. It covers a discussion on the optimal complexity of models, use of observations, calibration, control and sensitivity analysis. Special attention is given to the uncertainties encountered when using hydrological models for the simulation of extreme floods and long-term scenario simulations. Finally a few ethical problems in modelling are mentioned.

  • 168.
    Bergström, Sten
    et al.
    SMHI, Research Department, Hydrology.
    Andréasson, Johan
    SMHI, Professional Services.
    Graham, Phil
    SMHI, Professional Services.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Use of Hydrological Data and Climate Scenarios for Climate Change Detection in the Baltic Basin2004In: Study Conference on BALTEX: Conference Proceedings / [ed] Hans-Jörg Isemer, Risø National Laboratory Technical University of Denmark GKSS Forschungszentrum Geesthacht GmbH , 2004, Vol. 4, p. 158-159Conference paper (Other academic)
  • 169.
    Bergström, Sten
    et al.
    SMHI, Research Department, Hydrology.
    Brandt, Maja
    SMHI, Core Services.
    Gustafson, Arne
    SIMULATION OF RUNOFF AND NITROGEN LEACHING FROM 2 FIELDS IN SOUTHERN SWEDEN1987In: Hydrological Sciences Journal, ISSN 0262-6667, E-ISSN 2150-3435, Vol. 32, no 2, p. 191-205Article in journal (Refereed)
  • 170.
    Bergström, Sten
    et al.
    SMHI, Research Department, Hydrology.
    Carlsson, Bengt
    SMHI, Research Department, Hydrology.
    Hydrology of the Baltic Basin: Inflow of fresh water from rivers and land for the period 1950–19901993Report (Other academic)
    Abstract [en]

    A data base of monthly inflow of fresh water from rivers and land to the Baltic Sea and its subbasins is created. The data base covers the period 1950 - 1990 and is based on observations from the national hydrological services of the surrounding countries.

    The main features of the data base are presented including river flow of selected rivers and total inflow to the Baltic Sea and its subbasins. Long term, seasonal and short term variabilities are analysed and the effects of hydropower development are identified. An earlier data base by Mikulski (1982) is used for comparison and extension of the record to cover the period 1921 - 1990.

    It is concluded that the variability of inflow is great and that the decade 1981 - 1990 is the wettest in 70 years. The increase in runoff is mainly due to increasing river flow during the cold seasons. The effects of hydropower development are noticeable in the records for the Bothnian Bay and the Bothnian Sea.

  • 171.
    Bergström, Sten
    et al.
    SMHI, Research Department, Hydrology.
    Carlsson, Bengt
    SMHI, Research Department, Hydrology.
    RIVER RUNOFF TO THE BALTIC SEA - 1950-19901994In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 23, no 4-5, p. 280-287Article in journal (Refereed)
    Abstract [en]

    A database of monthly inflow of fresh water from rivers and land to the Baltic Sea and its subbasins is created. The database covers the period 1950-1990 and is based on observations from the national hydrological services of the surrounding countries. The main features of the database are presented including river flow of selected rivers and total inflow to the Baltic Sea and its subbasins. Long term, seasonal and short-term variabilities are analyzed and the effects of hydropower development are identified. An earlier database by Mikulski is used for comparison and extension of the record to cover the period 1921-1990. It is concluded that the variability of inflow is great and that the decade 1981-1990 was the wettest in 70 years. Wet years are also found in the 1920s. The increase in runoff is mainly due to increasing river flow during the cold seasons. The effects of hydropower development are noticeable in the records for the Bothnian Bay and the Bothnian Sea.

  • 172.
    Bergström, Sten
    et al.
    SMHI, Research Department, Hydrology.
    Carlsson, Bengt
    SMHI, Research Department, Hydrology.
    Gardelin, Marie
    SMHI, Professional Services.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Pettersson, Anna
    SMHI, Research Department, Hydrology.
    Rummukainen, Markku
    SMHI, Research Department, Climate research - Rossby Centre.
    Climate change impacts on runoff in Sweden - assessments by global climate models, dynamical downscaling and hydrological modelling2001In: Climate Research (CR), ISSN 0936-577X, E-ISSN 1616-1572, Vol. 16, no 2, p. 101-112Article in journal (Refereed)
    Abstract [en]

    The Swedish regional climate modelling programme, SWECLIM, started in 1997 with the main goal being to produce regional climate change scenarios over the Nordic area on a time scale of 50 to 100 yr. An additional goal is to produce water resources scenarios with a focus on hydropower production, dam safety, water supply and environmental aspects of water resources. The scenarios are produced by a combination of global climate models (GCMs), regional climate models and hydrological runoff models. The GCM simulations used thus far are 10 yr time slices from 2 different GCMs, UKMO HadCM2 from the Hadley Centre and the ECHAM4/OPYC3 of the Max Planck Institute for Meteorology. The regional climate model is a modified version of the international HIRLAM forecast model and the hydrological model is the HBV model developed at the Swedish Meteorological and Hydrological Institute. Scenarios of river runoff have been simulated for 6 selected basins covering the major climate regions in Sweden. Changes in runoff totals, runoff regimes and extreme values have been analysed with a focus on the uncertainties introduced by the choice of GCM and routines for estimation of evapotranspiration in the hydrological model. It is further shown how these choices affect the statistical return periods of future extremes in a design situation.

  • 173.
    Bergström, Sten
    et al.
    SMHI, Research Department, Hydrology.
    Ehlin, Ulf
    SMHI.
    Olsson, Per-Eric
    VASO.
    Riktlinjer och praxis vid dimensionering av utskov och dammar i USA: Rapport från en studieresa i oktober 19851986Report (Other academic)
    Abstract [sv]

    Under oktober månad 1985 företog vi en studieresa i USA på uppdrag av Flödeskommittén. Avsikten var att inhämta upplysningar om de riktlinjer, som tillämpas i USA för bestämning av dimensionerade flöden för utskov vid kraftverk och regleringsdammar. Inte minst viktigt var att genom personliga samtal med meteorologer, hydrologer och tekniker få ett grepp om metodernas fördelar och svagheter samt vilka subjektiva bedömningar, som påverkar beräkningsresultaten. Vi kom även att diskutera frågor om hydrologiska prognoser och datainsamlingssystem. 

  • 174.
    Bergström, Sten
    et al.
    SMHI, Research Department, Hydrology.
    Graham, Phil
    SMHI, Research Department, Climate research - Rossby Centre.
    Abstract to "On the scale problem in hydrological modelling" [Journal of Hydrology 211 (1998) 253-265]1999In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 217, no 3-4, p. 284-284Article in journal (Refereed)
  • 175.
    Bergström, Sten
    et al.
    SMHI, Research Department, Hydrology.
    Graham, Phil
    SMHI, Research Department, Climate research - Rossby Centre.
    On the scale problem in hydrological modelling1998In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 211, no 1-4, p. 253-265Article in journal (Refereed)
    Abstract [en]

    The problem of scales and particularly the modelling of macro or continental scale catchments in hydrology is addressed. It is concluded that the magnitude of the scale problem is related to the specific hydrologic problem to be solved and to the scientific approach and perspective of the modeller. A distributed modelling approach, based on variability parameters, is suggested for modelling of soil moisture dynamics and runoff generation. It is shown that the parameters of such an approach are relatively stable over a wide range of scales. An example of the application of a standard Version of the Swedish HBV hydrological model to the continental scale catchment of the Baltic Sea is shown and its usefulness is discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.

  • 176.
    Bergström, Sten
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Graham, Phil
    SMHI, Professional Services.
    Gardelin, Marie
    SMHI, Professional Services.
    Climate change impacts on the hydrology of the Baltic Basin.2001In: Proceedings of the third study conference on BALTEX / [ed] J. Meywerk, 2001, p. 17-18Conference paper (Other academic)
  • 177.
    Bergström, Sten
    et al.
    SMHI, Research Department, Hydrology.
    Harlin, Joakim
    SMHI.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    SPILLWAY DESIGN FLOODS IN SWEDEN .1. NEW GUIDELINES1992In: Hydrological Sciences Journal, ISSN 0262-6667, E-ISSN 2150-3435, Vol. 37, no 5, p. 505-519Article in journal (Refereed)
    Abstract [en]

    The new Swedish guidelines for the estimation of design floods for dams and spillways are presented, with emphasis on high-hazard dams. The method is based on a set of regional design precipitation sequences, rescaled for basin area, season and elevation above sea level, and a full hydrological model. A reservoir operation strategy is also a fundamental component of the guidelines. The most critical combination of flood generating factors is searched by systematically inserting the design precipitation sequence into a ten year climatological record, where the initial snowpack has been replaced by a statistical 30-year snowpack. The new guidelines are applicable to single reservoir systems as well as more complex hydroelectric schemes, and cover snowmelt floods, rain floods and combinations of the two. In order to study the probabilities of the computed floods and to avoid regional inconsistencies, extensive comparisons with observed floods and frequency analyses have been carried out.

  • 178.
    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.

  • 179.
    Bergström, Sten
    et al.
    SMHI, Research Department, Hydrology.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Pettersson, Anna
    SMHI, Research Department, Hydrology.
    Multi-variable parameter estimation to increase confidence in hydrological modelling2002In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 16, no 2, p. 413-421Article in journal (Refereed)
    Abstract [en]

    The expanding use and increased complexity of hydrological runoff models has given rise to a concern about overparameterization and risks for compensating errors. One proposed way out is the calibration and validation against additional observations, such as snow, soil moisture, groundwater or water quality. A general problem, however, when calibrating the model against more than one variable is the strategy for parameter estimation. The most straightforward method is to calibrate the model components sequentially. Recent results show that in this way the model may be locked up in a parameter setting, which is good enough for one variable but excludes proper simulation of other variables. This is particularly the case for water quality modelling, where a small compromise in terms of runoff simulation may lead to dramatically better simulations of water quality. This calls for an integrated model calibration procedure with a criterion that integrates more aspects on model performance than just river runoff. The use of multi-variable parameter estimation and internal control of the HBV hydrological model is discussed and highlighted by two case studies. The first example is from a forested basin in northern Sweden and the second one is from an agricultural basin in the south of the country. A new calibration strategy, which is integrated rather than sequential, is proposed and tested. It is concluded that comparison of model results with more measurements than only runoff can lead to increased confidence in the physical relevance of the model, and that the new calibration strategy can be useful for further model development. Copyright (C) 2002 John Wiley Sons, Ltd.

  • 180.
    Bergström, Sten
    et al.
    SMHI, Research Department, Hydrology.
    Sandén, Per
    SMHI.
    Gardelin, Marie
    SMHI, Professional Services.
    Analysis of climate-induced hydrochemical variations in till aquifers1990Report (Other academic)
    Abstract [en]

    An investigation of the relations between climatological factors and short term variabilityin groundwater storage and hydrochemistry in till aquifers is performed. The analysis isbased on a simple empirical hydrological model, the PULSE model, and groundwaterrecords from four sites in Sweden.The model proved to be capable of describing the dynamics of groundwater levels ordischarge, and at one of the sites it was possible to describe hydrochemical variations aswell. The application to the remaining three sites illustrated that groundwater chemistryshows a much more complex pattem of variations than does corresponding streamflowin this type of basin. The importance of areal variabilities within the recharge area isdiscussed and illustrated by a distribution of the model into two submodels when applyingit to one of the basins.

  • 181. Berlin, Mats
    et al.
    Persson, Torgny
    Jansson, Gunnar
    Haapanen, Matti
    Ruotsalainen, Seppo
    Bärring, Lars
    SMHI, Research Department, Climate research - Rossby Centre.
    Gull, Bengt Andersson
    Scots pine transfer effect models for growth and survival in Sweden and Finland2016In: Silva Fennica, ISSN 0037-5330, E-ISSN 2242-4075, Vol. 50, no 3, article id 1562Article in journal (Refereed)
    Abstract [en]

    In this study, we developed models of transfer effects for growth and survival of Scots pine (Pinus sylvestris L.) in Sweden and Finland using a general linear mixed-model approach. For model development, we used 378 provenance and progeny trials with a total of 276 unimproved genetic entries (provenances and stand seed check-lots) distributed over a wide variety of climatic conditions in both countries. In addition, we used 119 progeny trials with 3921 selected genetic entries (open-and control pollinated plus-tree families) for testing model performance. As explanatory variables, both climatic indices derived from high-resolution gridded climate datasets and geographical variables were used. For transfer, latitude (photoperiod) and, for describing the site, temperature sum were found to be main drivers for both survival and growth. In addition, interaction terms (between transfer in latitude and site altitude for survival, and transfer in latitude and temperature sum for growth) entail changed reaction patterns of the models depending on climatic conditions of the growing site. The new models behave in a way that corresponds well to previous studies and recommendations for both countries. The model performance was tested using selected plus-trees from open and control pollinated progeny tests. Results imply that the models are valid for both countries and perform well also for genetically improved material. These models are the first step in developing common deployment recommendations for genetically improved forest regeneration material in both Sweden and Finland.

  • 182. Berner, Judith
    et al.
    Achatz, Ulrich
    Batte, Lauriane
    Bengtsson, Lisa
    SMHI, Research Department, Meteorology.
    de la Camara, Alvaro
    Christensen, Hannah M.
    Colangeli, Matteo
    Coleman, Danielle R. B.
    Crommelin, Daaaan
    Dolaptchiev, Stamen I.
    Franzke, Christian L. E.
    Friederichs, Petra
    Imkeller, Peter
    Jarvinen, Heikki
    Juricke, Stephan
    Kitsios, Vassili
    Lott, Francois
    Lucarini, Valerio
    Mahajan, Salil
    Palmer, Timothy N.
    Penland, Cecile
    Sakradzija, Mirjana
    von Storch, Jin-Song
    Weisheimer, Antje
    Weniger, Michael
    Williams, Paul D.
    Yano, Jun-Ichi
    STOCHASTIC PARAMETERIZATION Toward a New View of Weather and Climate Models2017In: Bulletin of The American Meteorological Society - (BAMS), ISSN 0003-0007, E-ISSN 1520-0477, Vol. 98, no 3, p. 565-587Article in journal (Refereed)
  • 183. Berntell, Ellen
    et al.
    Zhang, Qiong
    Chafik, Leon
    Körnich, Heiner
    SMHI, Research Department, Meteorology.
    Representation of Multidecadal Sahel Rainfall Variability in 20th Century Reanalyses2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 10937Article in journal (Refereed)
  • 184.
    Berre, Loik
    SMHI, Research Department, Atmospheric remote sensing.
    Estimation of synoptic and mesoscale forecast error covariances in a limited-area model2000In: Monthly Weather Review, ISSN 0027-0644, E-ISSN 1520-0493, Vol. 128, no 3, p. 644-667Article in journal (Refereed)
    Abstract [en]

    Statistical and balance features of forecast errors are generally incorporated in the background constraint of variational data assimilation. Forecast error covariances are here estimated with a spectral approach and from a set of forecast differences; autocovariances are calculated with a nonseparable scheme, and multiple linear regressions are used in the formulation of cross covariances. Such an approach was first developed for global models; it is here adapted to ALADIN, a bi-Fourier high-resolution limited-area model, and extended to a multivariate study of humidity forecast errors. Results for autocovariances confirm the importance of nonseparability, in terms of both vertical variability of horizontal correlations and dependence of vertical correlations with horizontal scale; high-resolution spatial correlations are obtained, which should enable a high-resolution analysis. Moreover nonnegligible relationships are found between forecast errors of humidity and those of mass and wind fields.

  • 185. Betts, Richard A.
    et al.
    Alfieri, Lorenzo
    Bradshaw, Catherine
    Caesar, John
    Feyen, Luc
    Friedlingstein, Pierre
    Gohar, Laila
    Koutroulis, Aristeidis
    Lewis, Kirsty
    Morfopoulos, Catherine
    Papadimitriou, Lamprini
    Richardson, Katy J.
    Tsanis, Ioannis
    Wyser, Klaus
    SMHI, Research Department, Climate research - Rossby Centre.
    Changes in climate extremes, fresh water availability and vulnerability to food insecurity projected at 1.5 degrees C and 2 degrees C global warming with a higher-resolution global climate model2018In: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 376, no 2119, article id 20160452Article in journal (Refereed)
  • 186. Birch, C. E.
    et al.
    Brooks, I. M.
    Tjernstrom, M.
    Shupe, M. D.
    Mauritsen, T.
    Sedlar, Joseph
    SMHI, Research Department, Atmospheric remote sensing.
    Lock, A. P.
    Earnshaw, P.
    Persson, P. O. G.
    Milton, S. F.
    Leck, C.
    Modelling atmospheric structure, cloud and their response to CCN in the central Arctic: ASCOS case studies2012In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 12, no 7, p. 3419-3435Article in journal (Refereed)
    Abstract [en]

    Observations made during late summer in the central Arctic Ocean, as part of the Arctic Summer Cloud Ocean Study (ASCOS), are used to evaluate cloud and vertical temperature structure in the Met Office Unified Model (MetUM). The observation period can be split into 5 regimes; the first two regimes had a large number of frontal systems, which were associated with deep cloud. During the remainder of the campaign a layer of low-level cloud occurred, typical of central Arctic summer conditions, along with two periods of greatly reduced cloud cover. The short-range operational NWP forecasts could not accurately reproduce the observed variations in near-surface temperature. A major source of this error was found to be the temperature-dependant surface albedo parameterisation scheme. The model reproduced the low-level cloud layer, though it was too thin, too shallow, and in a boundary-layer that was too frequently well-mixed. The model was also unable to reproduce the observed periods of reduced cloud cover, which were associated with very low cloud condensation nuclei (CCN) concentrations (< 1 cm(-3)). As with most global NWP models, the MetUM does not have a prognostic aerosol/cloud scheme but uses a constant CCN concentration of 100 cm(-3) over all marine environments. It is therefore unable to represent the low CCN number concentrations and the rapid variations in concentration frequently observed in the central Arctic during late summer. Experiments with a single-column model configuration of the MetUM show that reducing model CCN number concentrations to observed values reduces the amount of cloud, increases the near-surface stability, and improves the representation of both the surface radiation fluxes and the surface temperature. The model is shown to be sensitive to CCN only when number concentrations are less than 10-20 cm(-3).

  • 187. Bishop, Kevin
    et al.
    Beven, Keith
    Destouni, Georgia
    Abrahamsson, Katarina
    Andersson, Lotta
    SMHI, Core Services.
    Johnson, Richard K.
    Rodhe, Johan
    Hjerdt, Niclas
    SMHI, Core Services.
    Nature as the "Natural" Goal for Water Management: A Conversation2009In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 38, no 4, p. 209-214Article in journal (Other academic)
    Abstract [en]

    The goals for water-quality and ecosystem integrity are often defined relative to "natural" reference conditions in many water-management systems, including the European Union Water Framework Directive. This paper examines the difficulties created for water management by using "natural" as the goal. These difficulties are articulated from different perspectives in an informal (fictional) conversation that takes place after a workshop on reference conditions in water-resources management. The difficulties include defining the natural state and modeling how a system might be progressed toward the natural, as well as the feasibility and desirability of restoring a natural state. The paper also considers the appropriateness for developing countries to adopt the use of natural as the goal for water management. We conclude that failure to critically examine the complexities of having "natural" as the goal will compromise the ability to manage the issues that arise in real basins by not making the ambiguities associated with this "natural" goal explicit. This is unfortunate both for the western world that has embraced this model of "natural as the goal" and for the developing world in so far as they are encouraged to adopt this model.

  • 188. Bjork, Goran
    et al.
    Nordberg, Kjell
    Arneborg, Lars
    SMHI, Research Department, Oceanography.
    Bornmalm, Lennart
    Harland, Rex
    Robijn, Ardo
    Odalen, Malin
    Seasonal oxygen depletion in a shallow sill fjord on the Swedish west coast2017In: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 175, p. 1-14Article in journal (Refereed)
  • 189. Bjork, Goran
    et al.
    Stranne, Christian
    Borenäs, Karin
    SMHI, Core Services.
    The Sensitivity of the Arctic Ocean Sea Ice Thickness and Its Dependence on the Surface Albedo Parameterization2013In: Journal of Climate, ISSN 0894-8755, E-ISSN 1520-0442, Vol. 26, no 4, p. 1355-1370Article in journal (Refereed)
    Abstract [en]

    In this study, the response of sea ice thickness to changes in the external forcing is investigated and particularly how this response depends on the surface albedo formulation by means of a one-dimensional coupled ocean-ice-atmosphere model. The main focus is on the thickness response to the atmospheric heat advection F-wall, solar radiation F-SW, and amount of snow precipitation S-prec. Different albedo parameterization schemes [ECHAM5, CSIRO, and Community Climate System Model, version 3 (CCSM3)] representing albedos commonly used in global climate models are compared together with more simplified schemes. Using different albedo schemes with the same external forcing produces large differences in ice thickness. The ice thickness response is similar for all realistic albedo schemes with a nearly linear decrease with increasing F-wall in the perennial ice regime and with a steplike transition into seasonal ice when F-wall exceeds a certain threshold. This transition occurs at an annual-mean ice thickness of 1.7-2.0 m. Latitudinal differences in solar insolation generally leads to increasing ice thickness toward the North Pole. The snow response varies significantly depending on which albedo scheme is used. The ECHAM5 scheme yields thinner ice with S-prec, the CSIRO scheme gives ice thickness nearly independent of S-prec, and with the CCSM3 scheme the ice thickness decreases with S-prec. A general result is that the modeled ice cover is rather sensitive to positive perturbations of the external heat supply when it is close to the transition such that just a small increase of, for example, F-wall can force the ice cover into the seasonal regime.

  • 190. Bjorkman, Christer
    et al.
    Kindvall, Oskar
    Hoglund, Solveig
    Lilja, Anna
    SMHI, Research Department, Climate research - Rossby Centre.
    Bärring, Lars
    SMHI, Research Department, Climate research - Rossby Centre.
    Eklund, Karin
    High Temperature Triggers Latent Variation among Individuals: Oviposition Rate and Probability for Outbreaks2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 1, article id e16590Article in journal (Refereed)
    Abstract [en]

    Background: It is anticipated that extreme population events, such as extinctions and outbreaks, will become more frequent as a consequence of climate change. To evaluate the increased probability of such events, it is crucial to understand the mechanisms involved. Variation between individuals in their response to climatic factors is an important consideration, especially if microevolution is expected to change the composition of populations. Methodology/Principal Findings: Here we present data of a willow leaf beetle species, showing high variation among individuals in oviposition rate at a high temperature (20 degrees C). It is particularly noteworthy that not all individuals responded to changes in temperature; individuals laying few eggs at 20 degrees C continued to do so when transferred to 12 degrees C, whereas individuals that laid many eggs at 20 degrees C reduced their oviposition and laid the same number of eggs as the others when transferred to 12 degrees C. When transferred back to 20 degrees C most individuals reverted to their original oviposition rate. Thus, high variation among individuals was only observed at the higher temperature. Using a simple population model and based on regional climate change scenarios we show that the probability of outbreaks increases if there is a realistic increase in the number of warm summers. The probability of outbreaks also increased with increasing heritability of the ability to respond to increased temperature. Conclusions/Significance: If climate becomes warmer and there is latent variation among individuals in their temperature response, the probability for outbreaks may increase. However, the likelihood for microevolution to play a role may be low. This conclusion is based on the fact that it has been difficult to show that microevolution affect the probability for extinctions. Our results highlight the urge for cautiousness when predicting the future concerning probabilities for extreme population events.

  • 191. Blauw, A. N.
    et al.
    Anderson, P.
    SMHI.
    Estrada, M.
    Johansen, M.
    Laanemets, J.
    Peperzak, L.
    Purdie, D.
    Raine, R.
    Vahtera, E.
    The use of fuzzy logic for data analysis and modelling of European harmful algal blooms: results of the HABES project2006In: African Journal of Marine Science, ISSN 1814-232X, E-ISSN 1814-2338, Vol. 28, no 2, p. 365-369Article in journal (Refereed)
    Abstract [en]

    Fuzzy logic was applied to model blooms of Nodularia spumigena, Dinophysis spp., Alexandrium minutum, Karenia mikimotoi and Phaeocystis globosa at various European sites as part of the Harmful Algal Blooms Expert System (HABES) project. This modelling approach was useful in performing integrated analyses of interacting physical and biological factors involved in HABs. A basic knowledge of HAB formation and sufficient data are a prerequisite for successful bloom prediction.

  • 192. Blazica, V.
    et al.
    Gustafsson, Nils
    SMHI, Research Department, Meteorology.
    Zagar, N.
    The impact of periodization methods on the kinetic energy spectra for limited-area numerical weather prediction models2015In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 8, no 1, p. 87-97Article in journal (Refereed)
    Abstract [en]

    The paper deals with the comparison of the most common periodization methods used to obtain spectral fields of limited-area models for numerical weather prediction. The focus is on the impact that the methods have on the spectra of the fields, which are used for verification and tuning of the models. A simplified model is applied with random fields that obey a known kinetic energy spectrum. The periodization methods under consideration are detrending, the discrete cosine transform and the application of an extension zone. For the extension zone, three versions are applied: the Boyd method, the ALADIN method and the HIRLAM method. The results show that detrending and the discrete cosine transform have little impact on the spectra, as does the Boyd method for extension zone. For the ALADIN and HIRLAM methods, the impact depends on the width of the extension zone - the wider the zone, the more artificial energy and the larger impact on the spectra. The width of the extension zone correlates to the modifications in the shape of the spectra as well as to the amplitudes of the additional energy in the spectra.

  • 193. Blenckner, T
    et al.
    Omstedt, Anders
    SMHI, Research Department, Oceanography.
    Rummukainen, Markku
    SMHI, Research Department, Climate research - Rossby Centre.
    A Swedish case study of contemporary and possible future consequences of climate change on lake function2002In: Aquatic Sciences, ISSN 1015-1621, E-ISSN 1420-9055, Vol. 64, no 2, p. 171-184Article in journal (Refereed)
    Abstract [en]

    A physical lake model was employed to obtain a basis of discussing the impact of climate variability and climate change on the ecology of Lake Erken, Sweden. The validity of this approach was tested by running the PROBE-lake model for a 30-year period (STD) with observed meteorological data. The lake is adequately modelled, as seen in the comparison with actual lake observations. The validated lake model was then forced with meteorological data obtained from a regional climate model (RCM) with a horizontal resolution of 44 km for present (CLTR) and 2 x CO(2) (SCEN) climate conditions. The CUR lake simulation compares reasonably with the STD. Applying the SCEN simulation leads to a climate change scenario for the lake. The physical changes include elevated temperatures, shorter periods of ice cover combined with two of ten years being totally ice-free, and changes in the mixing regime. The ecological consequences of the physical simulation results are derived from the historical dataset of Lake Erken. Consequences of a warmer climate could imply increased nutrient cycling and lake productivity. The results suggest that an application of RCMs with a suitable resolution for lakes in combination with physical lake models allows projection of the responses of lakes to a future climate.

  • 194. Bloeschl, Guenter
    et al.
    Hall, Julia
    Parajka, Juraj
    Perdigao, Rui A. P.
    Merz, Bruno
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Aronica, Giuseppe T.
    Bilibashi, Ardian
    Bonacci, Ognjen
    Borga, Marco
    Canjevac, Ivan
    Castellarin, Attilio
    Chirico, Giovanni B.
    Claps, Pierluigi
    Fiala, Kayroly
    Frolova, Natalia
    Gorbachova, Liudmyla
    Gul, Ali
    Hannaford, Jamie
    Harrigan, Shaun
    Kireeva, Maria
    Kiss, Andrea
    Kjeldsen, Thomas R.
    Kohnova, Silvia
    Koskela, Jarkko J.
    Ledvinka, Ondrej
    Macdonald, Neil
    Mavrova-Guirguinova, Maria
    Mediero, Luis
    Merz, Ralf
    Molnar, Peter
    Montanari, Alberto
    Murphy, Conor
    Osuch, Marzena
    Ovcharuk, Valeryia
    Radevski, Ivan
    Rogger, Magdalena
    Salinas, Jose L.
    Sauquet, Eric
    Sraj, Mojca
    Szolgay, Jan
    Viglione, Alberto
    Volpi, Elena
    Wilson, Donna
    Zaimi, Klodian
    Zivkovic, Nenad
    Changing climate shifts timing of European floods2017In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 357, no 6351, p. 588-590Article in journal (Refereed)
  • 195. Bloeschl, Guenter
    et al.
    Hall, Julia
    Viglione, Alberto
    Perdigao, Rui A. P.
    Parajka, Juraj
    Merz, Bruno
    Lun, David
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Aronica, Giuseppe T.
    Bilibashi, Ardian
    Bohac, Milon
    Bonacci, Ognjen
    Borga, Marco
    Canjevac, Ivan
    Castellarin, Attilio
    Chirico, Giovanni B.
    Claps, Pierluigi
    Frolova, Natalia
    Ganora, Daniele
    Gorbachova, Liudmyla
    Gul, Ali
    Hannaford, Jamie
    Harrigan, Shaun
    Kireeva, Maria
    Kiss, Andrea
    Kjeldsen, Thomas R.
    Kohnova, Silvia
    Koskela, Jarkko J.
    Ledvinka, Ondrej
    Macdonald, Neil
    Mavrova-Guirguinova, Maria
    Mediero, Luis
    Merz, Ralf
    Molnar, Peter
    Montanari, Alberto
    Murphy, Conor
    Osuch, Marzena
    Ovcharuk, Valeryia
    Radevski, Ivan
    Salinas, Jose L.
    Sauquet, Eric
    Sraj, Mojca
    Szolgay, Jan
    Volpi, Elena
    Wilson, Donna
    Zaimi, Klodian
    Zivkovic, Nenad
    Changing climate both increases and decreases European river floods2019In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 573, no 7772, p. 108-+Article in journal (Refereed)
    Abstract [en]

    Climate change has led to concerns about increasing river floods resulting from the greater water-holding capacity of a warmer atmosphere(1). These concerns are reinforced by evidence of increasing economic losses associated with flooding in many parts of the world, including Europe(2). Any changes in river floods would have lasting implications for the design of flood protection measures and flood risk zoning. However, existing studies have been unable to identify a consistent continental-scale climatic-change signal in flood discharge observations in Europe(3), because of the limited spatial coverage and number of hydrometric stations. Here we demonstrate clear regional patterns of both increases and decreases in observed river flood discharges in the past five decades in Europe, which are manifestations of a changing climate. Our results-arising from the most complete database of European flooding so far-suggest that: increasing autumn and winter rainfall has resulted in increasing floods in northwestern Europe; decreasing precipitation and increasing evaporation have led to decreasing floods in medium and large catchments in southern Europe; and decreasing snow cover and snowmelt, resulting from warmer temperatures, have led to decreasing floods in eastern Europe. Regional flood discharge trends in Europe range from an increase of about 11 per cent per decade to a decrease of 23 per cent. Notwithstanding the spatial and temporal heterogeneity of the observational record, the flood changes identified here are broadly consistent with climate model projections for the next century(4,5), suggesting that climate-driven changes are already happening and supporting calls for the consideration of climate change in flood risk management.

  • 196. Bloeschl, Gunter
    et al.
    Bierkens, Marc F. P.
    Chambel, Antonio
    Cudennec, Christophe
    Destouni, Georgia
    Fiori, Aldo
    Kirchner, James W.
    McDonnell, Jeffrey J.
    Savenije, Hubert H. G.
    Sivapalan, Murugesu
    Stumpp, Christine
    Toth, Elena
    Volpi, Elena
    Carr, Gemma
    Lupton, Claire
    Salinas, Jose
    Szeles, Borbala
    Viglione, Alberto
    Aksoy, Hafzullah
    Allen, Scott T.
    Amin, Anam
    Andreassian, Vazken
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Aryal, Santosh K.
    Baker, Victor
    Bardsley, Earl
    Barendrecht, Marlies H.
    Bartosova, Alena
    SMHI, Research Department, Hydrology.
    Batelaan, Okke
    Berghuijs, Wouter R.
    Beven, Keith
    Blume, Theresa
    Bogaard, Thom
    de Amorim, Pablo Borges
    Boettcher, Michael E.
    Boulet, Gilles
    Breinl, Korbinian
    Brilly, Mitja
    Brocca, Luca
    Buytaert, Wouter
    Castellarin, Attilio
    Castelletti, Andrea
    Chen, Xiaohong
    Chen, Yangbo
    Chen, Yuanfang
    Chifflard, Peter
    Claps, Pierluigi
    Clark, Martyn P.
    Collins, Adrian L.
    Croke, Barry
    Dathe, Annette
    David, Paula C.
    de Barros, Felipe P. J.
    de Rooij, Gerrit
    Di Baldassarre, Giuliano
    Driscoll, Jessica M.
    Duethmann, Doris
    Dwivedi, Ravindra
    Eris, Ebru
    Farmer, William H.
    Feiccabrino, James
    Ferguson, Grant
    Ferrari, Ennio
    Ferraris, Stefano
    Fersch, Benjamin
    Finger, David
    Foglia, Laura
    Fowler, Keirnan
    Gartsman, Boris
    Gascoin, Simon
    Gaume, Eric
    Gelfan, Alexander
    Geris, Josie
    Gharari, Shervan
    Gleeson, Tom
    Glendell, Miriam
    Bevacqua, Alena Gonzalez
    Gonzalez-Dugo, Maria P.
    Grimaldi, Salvatore
    Gupta, A. B.
    Guse, Bjoern
    Han, Dawei
    Hannah, David
    Harpold, Adrian
    Haun, Stefan
    Heal, Kate
    Helfricht, Kay
    Herrnegger, Mathew
    Hipsey, Matthew
    Hlavacikova, Hana
    Hohmann, Clara
    Holko, Ladislav
    Hopkinson, Christopher
    Hrachowitz, Markus
    Illangasekare, Tissa H.
    Inam, Azhar
    Innocente, Camyla
    Istanbulluoglu, Erkan
    Jarihani, Ben
    Kalantari, Zahra
    Kalvans, Andis
    Khanal, Sonu
    Khatami, Sina
    Kiesel, Jens
    Kirkby, Mike
    Knoben, Wouter
    Kochanek, Krzysztof
    Kohnova, Silvia
    Kolechkina, Alla
    Krause, Stefan
    Kreamer, David
    Kreibich, Heidi
    Kunstmann, Harald
    Lange, Holger
    Liberato, Margarida L. R.
    Lindquist, Eric
    Link, Timothy
    Liu, Junguo
    Loucks, Daniel Peter
    Luce, Charles
    Mahe, Gil
    Makarieva, Olga
    Malard, Julien
    Mashtayeva, Shamshagul
    Maskey, Shreedhar
    Mas-Pla, Josep
    Mavrova-Guirguinova, Maria
    Mazzoleni, Maurizio
    Mernild, Sebastian
    Misstear, Bruce Dudley
    Montanari, Alberto
    Mueller-Thomy, Hannes
    Nabizadeh, Alireza
    Nardi, Fernando
    Neale, Christopher
    Nesterova, Nataliia
    Nurtaev, Bakhram
    Odongo, Vincent O.
    Panda, Subhabrata
    Pande, Saket
    Pang, Zhonghe
    Papacharalampous, Georgia
    Perrin, Charles
    Pfister, Laurent
    Pimentel, Rafael
    Polo, Maria J.
    Post, David
    Sierra, Cristina Prieto
    Ramos, Maria-Helena
    Renner, Maik
    Reynolds, Jose Eduardo
    Ridolfi, Elena
    Rigon, Riccardo
    Riva, Monica
    Robertson, David E.
    Rosso, Renzo
    Roy, Tirthankar
    Sa, Joao H. M.
    Salvadori, Gianfausto
    Sandells, Mel
    Schaefli, Bettina
    Schumann, Andreas
    Scolobig, Anna
    Seibert, Jan
    Servat, Eric
    Shafiei, Mojtaba
    Sharma, Ashish
    Sidibe, Moussa
    Sidle, Roy C.
    Skaugen, Thomas
    Smith, Hugh
    Spiessl, Sabine M.
    Stein, Lina
    Steinsland, Ingelin
    Strasser, Ulrich
    Su, Bob
    Szolgay, Jan
    Tarboton, David
    Tauro, Flavia
    Thirel, Guillaume
    Tian, Fuqiang
    Tong, Rui
    Tussupova, Kamshat
    Tyralis, Hristos
    Uijlenhoet, Remko
    van Beek, Rens
    van der Ent, Ruud J.
    van der Ploeg, Martine
    Van Loon, Anne F.
    van Meerveld, Ilja
    van Nooijen, Ronald
    van Oel, Pieter R.
    Vidal, Jean-Philippe
    von Freyberg, Jana
    Vorogushyn, Sergiy
    Wachniew, Przemyslaw
    Wade, Andrew J.
    Ward, Philip
    Westerberg, Ida K.
    White, Christopher
    Wood, Eric F.
    Woods, Ross
    Xu, Zongxue
    Yilmaz, Koray K.
    Zhang, Yongqiang
    Twenty-three unsolved problems in hydrology (UPH) - a community perspective2019In: Hydrological Sciences Journal, ISSN 0262-6667, E-ISSN 2150-3435, Vol. 64, no 10, p. 1141-1158Article in journal (Refereed)
  • 197. Blom, Eva-Lotta
    et al.
    Kvarnemo, Charlotta
    Dekhla, Isabelle
    Schöld, Sofie
    SMHI, Core Services.
    Andersson, Mathias H.
    Svensson, Ola
    Amorim, M. Clara P.
    Continuous but not intermittent noise has a negative impact on mating success in a marine fish with paternal care2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 5494Article in journal (Refereed)
  • 198.
    Bodin, Svante
    SMHI, Research Department.
    Development on an unsteady atmospheric boundary layer model1974Report (Other academic)
    Abstract [en]

    To serve as an aid in preparing lecal ferecasts as well as landing ferecasts at airports, a develepment ef an atmospheric boundary layer model has been started at SMHI. The model is going to use large scale wind, temperature and moisture predictions from a numerical weather prediction model as variable boundary conditions. Instead ef using the ordinary Ekman boundary layer equations an approach due te L N Gutman (1969) has been used in deriving a set of one-dimensional boundary layer equations. It is shown that this formulation filters out inertial- diffusive oscillations, which are present in an Ekman boundary layer due to time variation in the geostrephic wind.

    Experiments with variable large scale winds have been done, using a simple dry medel with prescribed variations in the boundary values for wind and temperature. A turbulent exchange coefficient formulation has been used, which is based on Monin & Obukhov´s similarity theory and which uses a mixing length formulation due to Blackadar. For the numerical solution a Crank-Nicolson scheme has been used. The computations show large differences between the steady state and the unsteady state solutions.This is shown in wind hodegraphs as well as in time functions of friction velocity,u* and cross isobar angle. Finally, from two different analytical solutions as well as a finite difference solution of the heat conduction equation, heat fluxes at the earth's surface due to heat conduction in the soil have been computed. These analytical solutions have been compared in terms of accuracy and efficiency.

  • 199.
    Bodin, Svante
    SMHI, Research Department.
    En numerisk prognosmodell för det atmosfäriska gränsskiktet, grundad på den turbulenta energiekvationen1979Report (Other academic)
    Abstract [en]

    The inter est in numerical modeling of the atmosphericboundary layer has grown considerably over the lastdecade. At SMHI and el s ewhere boundary layer modelsfind app l i c a ti on s in local forecasting , especially atairports, i n a i r pollution diffusion and disper s ions t udi e s and i n wind energy programmes .In this report an one - dimensio nal nume r ical boundarylayer model is der iv e d a nd numeri cal simulatio ns ofboundary layer data f r om Australia and Finla nd arepresented and d is cussed. The model, which is the f i rststep towards a three-dimens ional model, is based onthe so-called Gutman a pproach and incorporates theturbulent energy e quation f or turb ulence closure . Ascale analysis is performed , that shows that unless agrid distance of 20 km or less can be use d i n a threedimensionalmodel it is more profitable t o use an onedimensionalone with more sophisticated physical parameterizations.The model also includ e s condensat i on, i e fog andclouds, and complete radiat i on computations. A predictiveequation for surface temperature is used inconjunction with a simple soil moisture model.The numerical solution employs a variety of the CrankNicolsonscheme called Laasonen's scheme. The verticalcoordinate is transformed log-linearly into a new heightcoordinate to allow better resolution close to theground. 35 grid points are used to describe the boundarylayer up to 2000 m. A time step of 4 minutes has beenused in the simulations.Two versions of the model, the Gutman version andausual "Ekman" version, have been tested on day 33 and34 of the Wangara data. The two versions have been comparedand the Ekman version has also been compared withthe simulations of Yamada & Mellor (1975).The results show that the Ekman version is superiorwhen simulating the wind of the Wangara data. The thermalboundary layer development is very well predictedby both versions. Comparisons with Yamada & Mellorspeak in favour of the present model.Conclusions are drawn and some future work is outlined .The model is intended to undergo operational tests atArlanda airport in the near future.

  • 200. Boergel, Florian
    et al.
    Frauen, Claudia
    Neumann, Thomas
    Schimanke, Semjon
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Impact of the Atlantic Multidecadal Oscillation on Baltic Sea Variability2018In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 45, no 18, p. 9880-9888Article in journal (Refereed)
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