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  • 251.
    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)
  • 252.
    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)
  • 253.
    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.

  • 254.
    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.

  • 255.
    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.

  • 256.
    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. 

  • 257.
    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)
  • 258.
    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.

  • 259.
    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)
  • 260.
    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.

  • 261.
    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.

  • 262.
    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.

  • 263.
    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.

  • 264. 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.

  • 265. 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)
  • 266. 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)
  • 267.
    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.

  • 268. 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)
  • 269. 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).

  • 270. 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.

  • 271. 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)
  • 272. 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.

  • 273. 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.

  • 274. 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.

  • 275. 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.

  • 276. 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.

  • 277. 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)
  • 278. 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)
  • 279. 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)
  • 280.
    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.

  • 281.
    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.

  • 282.
    Bodin, Svante
    et al.
    SMHI, Research Department.
    Fredriksson, Ulf
    SMHI, Core Services.
    Uncertainty in wind forecasting for wind power networks1980Report (Other academic)
  • 283. 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)
  • 284.
    Bojarova, Jelena
    et al.
    SMHI, Research Department.
    Gustafsson, Nils
    SMHI, Research Department, Meteorology.
    Relevance of climatological background error statistics for mesoscale data assimilation2019In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 71, no 1, article id 1615168Article in journal (Refereed)
  • 285. Bojarova, Jelena
    et al.
    Gustafsson, Nils
    SMHI, Research Department, Meteorology.
    Johansson, Åke
    SMHI, Research Department, Meteorology.
    Vignes, Ole
    The ETKF rescaling scheme in HIRLAM2011In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 63, no 3, p. 385-401Article in journal (Refereed)
    Abstract [en]

    The ETKF rescaling scheme has been implemented into the HIRLAM forecasting system in order to estimate the uncertainty of the model state. The main purpose is to utilize this uncertainty information for modelling of flow-dependent background error covariances within the framework of a hybrid variational ensemble data assimilation scheme. The effects of rank-deficiency in the ETKF formulation is explained and the need for variance inflation as a way to compensate for these effects is justified. A filter spin-up algorithm is proposed as a refinement of the variance inflation. The proposed spin-up algorithm will also act to prevent ensemble collapse since the ensemble will receive 'fresh blood' in the form of additional perturbation components, generated on the basis of a static background error covariance matrix. The resulting ETKF-based ensemble perturbations are compared with ensemble perturbations based on targeted singular vectors and are shown to have more realistic spectral characteristics.

  • 286. Bolin, Karl
    et al.
    Almgren, Martin
    Olsson, Esbjörn
    SMHI, Research Department, Meteorology.
    Karasalo, Ilkka
    Long term estimations of low frequency noise levels over water from an off-shore wind farm2014In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 135, no 3, p. 1106-1114Article in journal (Refereed)
    Abstract [en]

    This article focuses on computations of low frequency sound propagation from an off-shore wind farm. Two different methods for sound propagation calculations are combined with meteorological data for every 3 hours in the year 2010 to examine the varying noise levels at a reception point at 13 km distance. It is shown that sound propagation conditions play a vital role in the noise impact from the off-shore wind farm and ordinary assessment methods can become inaccurate at longer propagation distances over water. Therefore, this paper suggests that methodologies to calculate noise immission with realistic sound speed profiles need to be combined with meteorological data over extended time periods to evaluate the impact of low frequency noise from modern off-shore wind farms. (C) 2014 Acoustical Society of America.

  • 287. Bonaduce, Antonio
    et al.
    Staneva, Joanna
    Behrens, Arno
    Bidlot, Jean-Raymond
    Wilcke, Renate
    SMHI, Research Department, Climate research - Rossby Centre.
    Wave Climate Change in the North Sea and Baltic Sea2019In: Journal of Marine Science and Engineering, E-ISSN 2077-1312, Vol. 7, no 6, article id 166Article in journal (Refereed)
  • 288. Boone, Aaron
    et al.
    Samuelsson, Patrick
    SMHI, Research Department, Climate research - Rossby Centre.
    Gollvik, Stefan
    SMHI, Research Department, Meteorology.
    Napoly, Adrien
    Jarlan, Lionel
    Brun, Eric
    Decharme, Bertrand
    The interactions between soil-biosphere-atmosphere land surface model with a multi-energy balance (ISBA-MEB) option in SURFEXv8-Part 1: Model description2017In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 10, no 2, p. 843-872Article in journal (Refereed)
  • 289.
    Borenäs, Karin
    et al.
    SMHI, Core Services.
    Hietala, R.
    Laanearu, J.
    Lundberg, P.
    Some estimates of the Baltic deep-water transport through the Stolpe trench2007In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 59, no 2, p. 238-248Article in journal (Refereed)
    Abstract [en]

    The subsurface flow of high-saline water masses from the Bornholm Basin through the Stolpe Channel plays an important role for the renewal of the Baltic Central Basin deep waters. In order to determine whether rotating 11/2-layer hydraulic theory is an appropriate tool for describing this process, maximal-transport estimates based on climatological data from the Bornholm and Gdansk Basins have been established. These were found to deviate considerably from observational realities, and hence similar hydraulic considerations were also applied to more-or-less synoptic field data from a Finnish field campaign carried through in the mid-1980s. Also in this case significant differences were found between calculated transport capacity and observations. Since it furthermore was demonstrated that the characteristics of the observed cross-channel hydrographic structure could be explained using a frictional-balance model of the deep-water flow, it has been concluded that a hydraulic framework, although providing an upper bound of the transport, is of limited use when dealing with the Stolpe-Channel overflow. Although it cannot be excluded that the inflow is inviscid, but submaximal, it is more likely that the transport is governed by the combined effects of friction and wind forcing.

  • 290.
    Borenäs, Karin
    et al.
    SMHI, Core Services.
    Lake, Irene
    Lundberg, P A
    On the intermediate water masses of the Faroe-Bank Channel overflow2001In: Journal of Physical Oceanography, ISSN 0022-3670, E-ISSN 1520-0485, Vol. 31, no 7, p. 1904-1914Article in journal (Refereed)
    Abstract [en]

    A review of available hydrographic data from the Faroe-Bank Channel indicates that North Icelandic/Arctic Intermediate water masses are present in the passage to a larger extent than was previously believed. The presently compiled statistics, including results on the seasonality, are discussed in relation to previous investigations. Finally, a high quality subset of the hydrographic data is used for an analysis of the alongchannel mixing of the intermediate water masses.

  • 291.
    Borenäs, Karin
    et al.
    SMHI, Core Services.
    Lundberg, P
    The Faroe-Bank channel deep-water overflow2004In: Deep-sea research. Part II, Topical studies in oceanography, ISSN 0967-0645, E-ISSN 1879-0100, Vol. 51, no 4-5, p. 335-350Article in journal (Refereed)
    Abstract [en]

    In the late 1950s it was recognised that a considerable transport of water from the deeper reaches of the Norwegian Sea into the Atlantic takes place through the Faroe-Bank Channel, which thereby serves as an important source for the renewal of the North Atlantic Deep Water. Consequently, substantial efforts have, over the past decades, been dedicated towards quantifying the overflow as well as clarifying the underlying dynamics. In the present review, an attempt is made to summarise the main body of the observational results as well as some theoretical considerations regarding the dynamical mechanisms. The most prominent characteristic of the Faroe-Bank Channel overflow is that it is a persistent phenomenon with a yearly average deep-water (viz. T<5degreesC) transport of around 2 Sv. Using inviscid rotating hydraulics, the flow through the controlling section at the sill, furthermore, can be reasonably well predicted on the basis of upstream conditions in the Norwegian Sea. After passing the threshold the descending overflow plume is subject to intense mixing, a process very much in the focus of ongoing research. (C) 2004 Elsevier Ltd. All rights reserved.

  • 292. Borrego, C.
    et al.
    Amorim, Jorge Humberto
    SMHI, Research Department, Air quality.
    Tchepel, O.
    Dias, D.
    Rafael, S.
    Sa, E.
    Pimentel, C.
    Fontes, T.
    Fernandes, P.
    Pereira, S. R.
    Bandeira, J. M.
    Coelho, M. C.
    Urban scale air quality modelling using detailed traffic emissions estimates2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 131, p. 341-351Article in journal (Refereed)
    Abstract [en]

    The atmospheric dispersion of NOx and PM10 was simulated with a second generation Gaussian model over a medium-size south-European city. Microscopic traffic models calibrated with GPS data were used to derive typical driving cycles for each road link, while instantaneous emissions were estimated applying a combined Vehicle Specific Power/Co-operative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (VSP/EMEP) methodology. Site-specific background concentrations were estimated using time series analysis and a low-pass filter applied to local observations. Air quality modelling results are compared against measurements at two locations for a 1 week period. 78% of the results are within a factor of two of the observations for 1-h average concentrations, increasing to 94% for daily averages. Correlation significantly improves when background is added, with an average of 0.89 for the 24 h record. The results highlight the potential of detailed traffic and instantaneous exhaust emissions estimates, together with filtered urban background, to provide accurate input data to Gaussian models applied at the urban scale. (C) 2016 Elsevier Ltd. All rights reserved.

  • 293. Borsche, M.
    et al.
    Kaiser-Weiss, A. K.
    Undén, Per
    SMHI, Research Department, Meteorology.
    Kaspar, F.
    Methodologies to characterize uncertainties in regional reanalyses2015In: Advances in Science and Research, ISSN 1992-0628, E-ISSN 1992-0636, Vol. 12, p. 207-218Article in journal (Refereed)
    Abstract [en]

    When using climate data for various applications, users are confronted with the difficulty to assess the uncertainties of the data. For both in-situ and remote sensing data the issues of representativeness, homogeneity, and coverage have to be considered for the past, and their respective change over time has to be considered for any interpretation of trends. A synthesis of observations can be obtained by employing data assimilation with numerical weather prediction (NWP) models resulting in a meteorological reanalysis. Global reanalyses can be used as boundary conditions for regional reanalyses (RRAs), which run in a limited area (Europe in our case) with higher spatial and temporal resolution, and allow for assimilation of more regionally representative observations. With the spatially highly resolved RRAs, which exhibit smaller scale information, a more realistic representation of extreme events (e.g. of precipitation) compared to global reanalyses is aimed for. In this study, we discuss different methods for quantifying the uncertainty of the RRAs to answer the question to which extent the smaller scale information (or resulting statistics) provided by the RRAs can be relied on. Within the European Union's seventh Framework Programme (EU FP7) project Uncertainties in Ensembles of Regional Re-Analyses (UERRA) ensembles of RRAs (both multi-model and single model ensembles) are produced and their uncertainties are quantified. Here we explore the following methods for characterizing the uncertainties of the RRAs: (A) analyzing the feedback statistics of the assimilation systems, (B) validation against station measurements and (C) grids derived thereof, and (D) against gridded satellite data products. The RRA ensembles (E) provide the opportunity to derive ensemble scores like ensemble spread and other special probabilistic skill scores. Finally, user applications (F) are considered. The various methods are related to user questions they can help to answer.

  • 294.
    Bosshard, Thomas
    et al.
    SMHI, Research Department, Hydrology.
    Carambia, M.
    Goergen, K.
    Kotlarski, S.
    Krahe, P.
    Zappa, M.
    Schaer, C.
    Quantifying uncertainty sources in an ensemble of hydrological climate-impact projections2013In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 49, no 3, p. 1523-1536Article in journal (Refereed)
    Abstract [en]

    The quantification of uncertainties in projections of climate impacts on river streamflow is highly important for climate adaptation purposes. In this study, we present a methodology to separate uncertainties arising from the climate model (CM), the statistical postprocessing (PP) scheme, and the hydrological model (HM). We analyzed ensemble projections of hydrological changes in the Alpine Rhine (Eastern Switzerland) for the near-term and far-term scenario periods 2024-2050 and 2073-2099 with respect to 1964-1990. For the latter scenario period, the model ensemble projects a decrease of daily mean runoff in summer (-32.2%, range [-45.5% to -8.1%]) and an increase in winter (+41.8%, range [+4.8% to +81.7%]). We applied an analysis of variance model combined with a subsampling procedure to assess the importance of different uncertainty sources. The CMs generally are the dominant source in summer and autumn, whereas, in winter and spring, the uncertainties due to the HMs and the statistical PP gain importance and even partly dominate. In addition, results show that the individual uncertainties from the three components are not additive. Rather, the associated interactions among the CM, the statistical PP scheme, and the HM account for about 5%-40% of the total ensemble uncertainty. The results indicate, in distinction to some previous studies, that none of the investigated uncertainty sources are negligible, and some of the uncertainty is not attributable to individual modeling chain components but rather depends upon interactions. Citation: Bosshard, T., M. Carambia, K. Goergen, S. Kotlarski, P. Krahe, M. Zappa, and C. Schar (2013), Quantifying uncertainty sources in an ensemble of hydrological climate-impact projections, Water Resour. Res., 49, 1523-1536, doi: 10.1029/2011WR011533.

  • 295.
    Bosshard, Thomas
    et al.
    SMHI, Research Department, Hydrology.
    Kotlarski, Sven
    Zappa, Massimiliano
    Schaer, Christoph
    Hydrological Climate-Impact Projections for the Rhine River: GCM-RCM Uncertainty and Separate Temperature and Precipitation Effects2014In: Journal of Hydrometeorology, ISSN 1525-755X, E-ISSN 1525-7541, Vol. 15, no 2, p. 697-713Article in journal (Refereed)
    Abstract [en]

    Climate change is expected to affect the hydrological cycle, with considerable impacts on water resources. Climate-induced changes in the hydrology of the Rhine River (Europe) are of major importance for the riparian countries, as the Rhine River is the most important European waterway, serves as a freshwater supply source, and is prone to floods and droughts. Here regional climate model data from the Ensemble-Based Predictions of Climate Changes and their Impacts (ENSEMBLES) project is used to drive the hydrological model Precipitation-Runoff-Evapotranspiration-Hydrotope (PREVAH) and to assess the impact of climate change on the hydrology in the Rhine basin. Results suggest increases in monthly mean runoff during winter and decreases in summer. At the gauge Cologne and for the period 2070-99 under the A1B scenario of the Special Report on Emissions Scenarios, projected decreases in summer vary between -9% and -40% depending on the climate model used, while increases in winter are in the range of +4% to +51%. These projected changes in mean runoff are generally consistent with earlier studies, but the derived spread in the runoff projections appears to be larger. It is demonstrated that temperature effects (e.g., through altered snow processes) dominate in the Alpine tributaries, while precipitation effects dominate in the lower portion of the Rhine basin. Analyses are also presented for selected extreme runoff indices.

  • 296. Boucher, Etienne
    et al.
    Nicault, Antoine
    Arseneault, Dominique
    Begin, Yves
    Karami, Mehdi Pasha
    SMHI, Research Department, Climate research - Rossby Centre.
    Decadal Variations in Eastern Canada's Taiga Wood Biomass Production Forced by Ocean-Atmosphere Interactions2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 2457Article in journal (Refereed)
  • 297. Bourgeois, Quentin
    et al.
    Ekman, Annica M. L.
    Renard, Jean-Baptiste
    Krejci, Radovan
    Devasthale, Abhay
    SMHI, Research Department, Atmospheric remote sensing.
    Bender, Frida A. -M.
    Riipinen, Ilona
    Berthet, Gwenael
    Tackett, Jason L.
    How much of the global aerosol optical depth is found in the boundary layer and free troposphere?2018In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 18, no 10, p. 7709-7720Article in journal (Refereed)
  • 298. Bowling, L C
    et al.
    Lettenmaier, D P
    Nijssen, B
    Graham, Phil
    SMHI, Research Department, Climate research - Rossby Centre.
    Clark, D B
    El Maayar, M
    Essery, R
    Goers, S
    Gusev, Y M
    Habets, F
    van den Hurk, B
    Jin, J M
    Kahan, D
    Lohmann, D
    Ma, X Y
    Mahanama, S
    Mocko, D
    Nasonova, O
    Niu, G Y
    Samuelsson, Patrick
    SMHI, Research Department, Climate research - Rossby Centre.
    Shmakin, A B
    Takata, K
    Verseghy, D
    Viterbo, P
    Xia, Y L
    Xue, Y K
    Yang, Z L
    Simulation of high-latitude hydrological processes in the Torne-Kalix basin: PILPS phase 2(e) - 1: Experiment description and summary intercomparisons2003In: Global and Planetary Change, ISSN 0921-8181, E-ISSN 1872-6364, Vol. 38, no 1-2, p. 1-30Article in journal (Refereed)
    Abstract [en]

    Twenty-one land-surface schemes (LSSs) participated in the Project for Intercomparison of Land-surface Parameterizations (PILPS) Phase 2(e) experiment, which used data from the Tome-Kalix Rivers in northern Scandinavia. Atmospheric forcing data (precipitation, air temperature, specific humidity, wind speed, downward shortwave and longwave radiation) for a 20-year period (1979-1998) were provided to the 21 participating modeling groups for 218 1/4degrees grid cells that represented the study domain. The first decade (1979-1988) of the period was used for model spin-up. The quality of meteorologic forcing variables is of particular concern in high-latitude experiments and the quality of the gridded dataset was assessed to the extent possible. The lack of sub-daily precipitation, underestimation of true precipitation and the necessity to estimate incoming solar radiation were the primary data concerns for this study. The results from two of the three types of runs are analyzed in this, the first of a three-part paper: (1) calibration-validation runs-calibration of model parameters using observed streamflow was allowed for two small catchments (570 and 1300 km(2)), and parameters were then transferred to two other catchments of roughly similar size (2600 and 1500 km(2)) to assess the ability of models to represent ungauged areas elsewhere; and 2) reruns-using revised forcing data (to resolve problems with apparent underestimation of solar radiation of approximately 36%, and certain other problems with surface wind in the original forcing data). Model results for the period 1989-1998 are used to evaluate the performance of the participating land-surface schemes in a context that allows exploration of their ability to capture key processes spatially. In general, the experiment demonstrated that many of the LSSs are able to capture the limitations imposed on annual latent heat by the small net radiation available in this high-latitude environment. Simulated annual average net radiation varied between 16 and 40 W/m(2) for the 21 models, and latent heat varied between 18 and 36 W/m(2). Among-model differences in winter latent heat due to the treatment of aerodynamic resistance appear to be at least as important as those attributable to the treatment of canopy interception. In many models, the small annual net radiation forced negative sensible heat on average, which varied among the models between - 11 and 9 W/m(2). Even though the largest evaporation rates occur in the summer (June, July and August), model-predicted snow sublimation in winter has proportionately more influence on differences in annual runoff volume among the models. A calibration experiment for four small sub-catchments of the Torne-Kalix basin showed that model parameters that are typically adjusted during calibration, those that control storage of moisture in the soil column or on the land surface via ponding, influence the seasonal distribution of runoff, but have relatively little impact on annual runoff ratios. Similarly, there was no relationship between annual runoff ratios and the proportion of surface and subsurface discharge for the basin as a whole. (C) 2003 Elsevier Science B.V. All rights reserved.

  • 299. Bowling, Laura
    et al.
    Lettenmaier, Dennis
    Graham, Phil
    SMHI, Professional Services.
    Land-surface parameterizations in northern regions: preliminary results from the PILPS 2e model intercomparison.2001In: Third study conference on BALTEX / [ed] Jens Meywerk, 2001, p. 25-26Conference paper (Other academic)
  • 300. Brandefelt, J.
    et al.
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Naslund, J. -O
    Strandberg, Gustav
    SMHI, Research Department, Climate research - Rossby Centre.
    Voelker, A. H. L.
    Wohlfarth, B.
    A coupled climate model simulation of Marine Isotope Stage 3 stadial climate2011In: Climate of the Past, ISSN 1814-9324, E-ISSN 1814-9332, Vol. 7, no 2, p. 649-670Article in journal (Refereed)
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