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  • 201. 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.

  • 202. 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)
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  • 203.
    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.

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  • 204.
    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.

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  • 205.
    Bodin, Svante
    et al.
    SMHI, Research Department.
    Fredriksson, Ulf
    SMHI, Core Services.
    Uncertainty in wind forecasting for wind power networks1980Report (Other academic)
    Abstract [en]

    Accurate wind forecasts will be essential in the utilization of wind energy conversion systems (WECS). In order to assess the reliability at present forecast methods for wind speed forecast data from the USA and Sweden have been verified. Data represent different methods, numerical/statistical and subjective, different locations, seasons and heights. However, the data sets are too small to allow any definite conclusions. The results point to that none of the tested forecast methods meet the requirements on forecast error put forward by utilities. The best forecasts were obtained by subjective methods based on numerical prediction for projection times less than +18h. Beyond that time objective, numerical/statistical methods showed to be better. National weather services are recommended to improve forecast methods for shortrange forecasts, 0-12 hours ahead. To obtain sufficient forecast accuracy future WECS sites must also supply relevant observations of low level atmospheric structure.

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  • 206. 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)
  • 207.
    Bojarova, Jelena
    et al.
    SMHI, Research Department, Meteorology.
    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)
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  • 208. 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.

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  • 209. 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.

  • 210. 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)
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  • 211. 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)
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  • 212. 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.

  • 213. 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.

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  • 214.
    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.

  • 215.
    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.

  • 216. 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)
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  • 217. 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)
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  • 218. 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.

  • 219. 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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  • 220. Brandefelt, Jenny
    et al.
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Näslund, Jens-Ove
    Strandberg, Gustav
    Voelker, Antje
    Wohlfarth, Barbara
    The importance of equilibration in glacial climate simulations2010In: Geophysical Research Abstracts, 2010, Vol. 12, article id EGU2010-10736Conference paper (Refereed)
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  • 221.
    Brandt, Maja
    et al.
    SMHI, Core Services.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    INTEGRATION OF FIELD DATA INTO OPERATIONAL SNOWMELT-RUNOFF MODELS1994In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 25, no 1-2, p. 101-112Article in journal (Refereed)
    Abstract [en]

    Conceptual runoff models have become standard tools for operational hydrological forecasting in Scandinavia. These models are normally based on observations from the national climatological networks, but in mountainous areas the stations are few and sometimes not representative. Due to the great economic importance of good hydrological forecasts for the hydro-power industry attempts have been made to improve the model simulations by support from field observations of the snowpack. The snowpack has been mapped by several methods; airborne gamma-spectrometry, airborne georadars, satellites and by conventional snow courses. The studies cover more than ten years of work in Sweden. The conclusion is that field observations of the snow cover have a potential for improvement of the forecasts of inflow to the reservoirs in the mountainous part of the country, where the climatological data coverages is poor. This is pronounced during years with unusual snow distribution. The potential for model improvement is smaller in the climatologically more homogeneous forested lowlands, where the climatological network is denser. The costs of introduction of airborne observations into the modelling procedure are high and can only be justified in areas of great hydropower potential.

  • 222.
    Brandt, Maja
    et al.
    SMHI, Core Services.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    Gardelin, Marie
    SMHI, Professional Services.
    MODELING THE EFFECTS OF CLEARCUTTING ON RUNOFF - EXAMPLES FROM CENTRAL SWEDEN1988In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 17, no 5, p. 307-313Article in journal (Refereed)
  • 223.
    Brandt, Maja
    et al.
    SMHI, Core Services.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    Gardelin, Marie
    SMHI, Professional Services.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Modellberäkning av extrem effektiv nederbörd1987Report (Other academic)
    Abstract [sv]

    Följande analys av vattenbalansen vid extrema situationer är ett led i Flödeskommittens arbete med att ta fram nya riktlinjer för dimensioneringsberäkningar för dammar och utskov, som inleddes våren 1985 (Ehlin, 1986). Frågan fick förnyad aktualitet i samband med höstflöden 1985 och 1986, som orsakade översvämningar och ett antal mindre dammras.De viktigaste faktorerna för beräkning av dimensionerande flöden är arealnederbörd, snösmältning, markfuktighet samt flödessituationen före flödet. En analys av extrem nederbörd har utförts (Vedin och Eriksson, 1986). För beräkning av effekten av den extrema nederbörden på flödet behöver även kombinationer av eventuell snösmältning och markfuktighetsunderskott i marken vara kända. Hur stor snösmältning kan tänkas ske i ett avrinningsområde? Kan vi räkna med att marken är helt mättad? Ett sätt att analysera detta är att med HBV-modellen ta fram extrema arealnederbörds- och snösmältningsvärden samt lägsta  markfuktighetsunderskott. I denna rapport redovisas en analys, som bygger på HBV-modellberäkningar i tjugofem avrinningsområden. Sammanlagt täcker områdena 79 000 km2 av Sveriges totala yta på449 000 km2. Den sammantagna tidsperioden för beräkningarna är475 år.

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  • 224.
    Brandt, Maja
    et al.
    SMHI, Core Services.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    Sandén, Per
    SMHI, Research Department, Hydrology.
    ENVIRONMENTAL IMPACTS OF AN OLD MINE TAILINGS DEPOSIT - MODELING OF WATER-BALANCE, ALKALINITY AND PH1987In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 18, no 4-5, p. 291-300Article in journal (Refereed)
  • 225.
    Brandt, Maja
    et al.
    SMHI, Core Services.
    Edler, Lars
    SMHI, Research Department, Oceanography.
    Andersson, Lars
    SMHI, Core Services.
    Översvämningar längs Oder och Wisla sommaren 1997 samt effekterna i Östersjön1998Report (Other academic)
    Abstract [sv]

    I juli drabbades Tjeckien och Polen av mycket intensiva regnväder. Det första kom 4-9/7 och det andra inträffade 18-21/7. Över floderna Oder och Wislas avrinningsområden föll 3-4 gånger så mycket nederbörd som normalt. Utifrån vattenföringuppgifterna beräknades, att det under perioden 11/7-31/8 hade runnit ut 17 km3 från dessa floder till Östersjön. Den normala avrinningen från Oder och Wisla är under denna tidsperiod ca 6 km3, vilket innebär ett överskott på ca 11 km3• Det kan jämföras med en veckas inflöde genom Öresund, som är av storleksordningen 10 km3.

    De stora regnmängderna medförde, att stora områden översvämmades främst längs Oder och att flodvattnet förde med sig material och föroreningar längs vattendragen. De svenska hydrografiska basundersökningarna i södra Östersjön intensifierades för att undersöka flodvattnets spridning och materialtransport i södra Östersjön. Undersökningarna utfördes till största delen av SMHI, och i ett nära samarbete med Naturvårdsverket, Fiskeriverket, IVL och Kustbevakningen. Tyska och polska fartyg utförde även intensiva mätningar under den aktuella tiden.

    Flodvattnets väg ut i Östersjön prognostiserades och följdes på ett antal olika sätt. Vinduppgifter, den oceanografiska modellen HIROMB samt spridningsmodell för olja och kemikalier användes för att prognostisera vattnets väg samtidigt som översvämningsvattnet följdes med hjälp av satellitbilder och fartygsmätningar.

    Wisla rinner ut i Gdanskbukten, medan Oder rinner ut i Pommerska bukten efter att ha passerat Szczecin-lagunen. De uppmätta närsaltkoncentrationerna i bukterna var i samma storleksordning som de maximala halter som uppmätts under vårperioderna de senaste 25 åren. Det näringsrika vattnet orsakade en kraftig primärproduktion i bukterna. I slutet av juli rådde västliga vindar, som transporterade det utströmmande vattnet från Wisla och Oder österut längs den polska kusten. I början av augusti vände vinden och blev ostlig. Vädret var varmt och soligt, och vattnet transporterade långsamt västerut. Någon påverkan längre ut från kusten registrerades inte och några långtidseffekter förväntas inte heller ske.

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  • 226. Breuer, L.
    et al.
    Huisman, J. A.
    Willems, P.
    Bormann, H.
    Bronstert, A.
    Croke, B. F. W.
    Frede, H. -G
    Graeff, T.
    Hubrechts, L.
    Jakeman, A. J.
    Kite, G.
    Lanini, J.
    Leavesley, G.
    Lettenmaier, D. P.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Seibert, J.
    Sivapalan, M.
    Viney, N. R.
    Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM). I: Model intercomparison with current land use2009In: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 32, no 2, p. 129-146Article in journal (Refereed)
    Abstract [en]

    This paper introduces the project on 'Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM)' that aims at investigating the envelope of predictions on changes in hydrological fluxes due to land use change. As part of a series of four papers, this paper outlines the motivation and setup of LUCHEM, and presents a model intercomparison for the present-day simulation results. Such an intercomparison provides a valuable basis to investigate the effects of different model structures on model predictions and paves the ground for the analysis of the performance of multi-model ensembles and the reliability of the scenario predictions in companion papers. in this study, we applied a set of 10 lumped, semi-lumped and fully distributed hydrological models that have been previously used in land use change studies to the low mountainous Dill catchment. Germany. Substantial differences in model performance were observed with Nash-Sutcliffe efficiencies ranging from 0.53 to 0.92. Differences in model performance were attributed to (1) model input data, (2) model calibration and (3) the physical basis of the models. The models were applied with two sets of input data: an original and a homogenized data set. This homogenization of precipitation, temperature and leaf area index was performed to reduce the variation between the models. Homogenization improved the comparability of model simulations and resulted in a reduced average bias, although some variation in model data input remained. The effect of the physical differences between models on the long-term water balance was mainly attributed to differences in how models represent evapotranspiration. Semi-lumped and lumped conceptual models slightly outperformed the fully distributed and physically based models. This was attributed to the automatic model calibration typically used for this type of models. Overall, however, we conclude that there was no superior model if several measures of model performance are considered and that all models are suitable to participate in further multi-model ensemble set-ups and land use change scenario investigations. (C) 2008 Elsevier Ltd. All rights reserved.

  • 227.
    Bringfelt, Bertil
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Räisänen, Jouni
    SMHI, Research Department, Climate research - Rossby Centre.
    Gollvik, Stefan
    Meterologi.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Graham, Phil
    SMHI, Professional Services.
    Ullerstig, Anders
    SMHI, Research Department, Climate research - Rossby Centre.
    The land surface treatment for the Rossby Centre Regional Atmospheric Climate Model - version 2 (RCA2)2001Report (Other academic)
    Abstract [en]

    A new version of the land surface scheme has been completed and is now applied in comparative tests of version 2 of the Rossby Centre Regional Atmospheric Climate Model (RCA2) using analysed fields from the ECMWF reanalysis project (ERA). The scheme contains two soil layers and a vegetation layer. There are two prognostic temperatures, one covering the top soil layer plus vegetation and one for a second, deeper soil layer. There is also a third, bottom soil temperature relaxed to six-hourly ERA fields. For soil moisture there are two prognostic layers but no bottom relaxation is used. A hydrologically-based soil moisture model (beta model) is used to represent subgrid soil moisture variability. A hydrological snow model makes regard to subgrid temperature variability using a geographical database for variance of topography. There are equations for heat and moisture exchange between the two soil layers. Here the hydraulic and thermal properties depend on soil type and soil moisture. Transpiration flux transports moisture from both soil layers depending on a stomatal resistance of vegetation surfaces as function of daylight intensity, soil water deficit, fraction of frozen soil water, air temperature and water vapour pressure deficit in the air. A treatment of rainfall interception on vegetation is used, broadly following the ISBA model, with a vegetation layer storing intercepted water. Subgrid weighting of albedo, surface roughness and parameters for calculating surface resistance is made using a geographical database for area fraction of forest and open land. The leaf area index varies seasonally for short vegetation and for deciduous forest, but not for coniferous forest. A soil freezing/melting algorithm influencing soil temperature is used. Implicit methods are used for solving the equations of most surface variables. A summary of model results compared to observations, is given at the end of the report.

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  • 228.
    Bringfelt, Björn
    SMHI, Research Department, Climate research - Rossby Centre.
    PARTICLE CONCENTRATION MODEL IN A SMALL TOWN STREET BASED ON RECEPTOR STUDIES1987In: Journal of Aerosol Science, ISSN 0021-8502, E-ISSN 1879-1964, Vol. 18, no 6, p. 841-844Article in journal (Refereed)
  • 229.
    Bringfelt, Björn
    et al.
    SMHI.
    Backström, Hans
    SMHI, Professional Services.
    Kindell, Sven
    SMHI, Professional Services.
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    Persson, Christer
    SMHI, Research Department, Air quality.
    Ullerstig, Anders
    SMHI, Research Department, Climate research - Rossby Centre.
    Calculations of PM-10 concentrations in Swedish cities - Modelling of inhalable particles1997Report (Other academic)
    Abstract [en]

    The project was initiated by the Swedish Environmental Protection Agency in order to improve the basis for making standards for PM-10 concentrations in urban air. Model development has been made for Norrköping and Gothenburg. Modelling has been necessary of both long-range and local contributions.

    The long-range dispersion has been simulated by the MATCH-Europe and MATCH-Sweden models, the former being a conventional dispersion model based on meteorology and emission data and the latter including also results from background air pollution measurements in Sweden and neighbouring countries.

    For the local scale, both car exhaust panicles and resuspended particles from a traffic source inventory are dispersed in the city using meteorological data and a Gaussian dispersion mode! and, if needed, a street canyon dispersion submodel. For panicle resuspension, a new model has been developed. The parameters of the resuspension model have been adjusted to two streets/measuring periods in Norrköping.

    At street level in Norrköping, the local model showed to contribute to a large part of the total concentration, especially in late winter and early spring due to resuspension. The MATCH mode! gives same underestimate due to the absence of organic compounds and simulation of PM-2.5 instead of PM-10. However, at some episodes in Norrköping and, in general, for a station at roof level in central Gothenburg and at the rural station Aspvreten, the model estimates of regional PM-2.5 concentrations constitute a larger part of the observed PM-10 concentrations. A good covariation in time with measured data occurs for both the MATCH model and the local model.

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  • 230.
    Bringfelt, Björn
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Heikinheimo, M
    Gustafsson, Nils
    SMHI, Research Department, Meteorology.
    Perov, Veniamin
    SMHI, Research Department, Meteorology.
    Lindroth, A
    A new land-surface treatment for HIRLAM - comparisons with NOPEX measurements1999In: Agricultural and Forest Meteorology, ISSN 0168-1923, E-ISSN 1873-2240, Vol. 98-9, p. 239-256Article in journal (Refereed)
    Abstract [en]

    In order to improve the accuracy of forecasting near-surface atmospheric variables over a heterogeneous landscape, a framework of subgrid surface types and the ISBA parameterisation scheme for land surfaces have been tested in the operational weather forecast model HIRLAM, using a 5.5 km grid resolution. Surface energy fluxes measured during a single summer day at six fixed sites in the NOPEX area, representing agricultural fields, boreal forests and lakes, were used for verification. Both, in-situ field measurements and the HIRLAM simulation indicated that the Bowen ratio over forests was about twice as large as that of adjacent agricultural fields. This difference could be explained by the more effective turbulent mixing and larger surface resistance associated with the forest, thus making the sensible heat flux relatively large there. The use of initial soil moisture from a routine hydrological model gave improved agreement with measured surface fluxes and radiosonde temperature and humidity profiles compared to initialising from routine HIRLAM surface data. The differences in heat fluxes between the various surface types were also demonstrated by airborne flux measurements flown along a track at a height of ca. 100 m above the terrain. Modelled heat fluxes along the flight track were considerably smoothed due to the grid resolution used, e.g. the effect of a lake in reducing grid-averaged sensible heat flux could only be weakly detected, because the lake surface represented only 10% of the grid area. When the proportion of a contrasting surface type (lake) was altered from 10 to 100%, the surface fluxes calculated for the lake surface were almost unchanged; the results of the comparison did not provide evidence that more complex aggregation schemes for heat fluxes than straightforward area-weighted averaging would be required. The hourly variation of the modelled and simulated heat fluxes during the day studied could not be directly compared, because the simulated cloudiness did not exactly match that observed at the field sites. When the simulated net radiation was replaced with direct measurements, the model-based estimates of sensible and latent heat fluxes were closer to the corresponding field measurements. The divergence of sensible heat flux with height, as inferred from the tower measurements made over the forest, were supported by the aircraft measurements and the HIRLAM simulations. (C) 1999 Elsevier Science B.V. All rights reserved.

  • 231.
    Bringfelt, Björn
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    LINDROTH, A
    SYNOPTIC EVAPOTRANSPIRATION MODEL APPLIED TO 2 NORTHERN FORESTS OF DIFFERENT DENSITY1987In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 95, no 3-4, p. 185-201Article in journal (Refereed)
  • 232. Brodeau, Laurent
    et al.
    Koenigk, Torben
    SMHI, Research Department, Climate research - Rossby Centre.
    Extinction of the northern oceanic deep convection in an ensemble of climate model simulations of the 20th and 21st centuries2016In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 46, no 9-10, p. 2863-2882Article in journal (Refereed)
  • 233.
    Broman, Barry
    SMHI, Research Department, Climate research - Rossby Centre.
    Oceanografiska stationsnät: Svenskt Vattenarkiv1986Report (Other academic)
    Abstract [sv]

    Oceanografiska stationsnät. Svenskt Vattenarkiv.

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  • 234.
    Broman, Barry
    SMHI, Research Department, Climate research - Rossby Centre.
    Uppföljning av sjövärmepump i Lilla Värtan1986Report (Other academic)
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  • 235.
    Broman, Barry
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Hammarklint, Thomas
    Rannat, Kalev
    Soomere, Tarmo
    Valdmann, Ain
    Trends and extremes of wave fields in the north-eastern part of the Baltic Proper2006In: Oceanologia, ISSN 0078-3234, Vol. 48, p. 165-184Article in journal (Refereed)
    Abstract [en]

    The paper analyses one of the longest contemporary wave measurements in the northern Baltic Sea, performed at Almagrundet 1978-2003. This record contains the roughest instrumentally measured wave conditions (significant wave height = c. 7.8 m) in the northern Baltic Proper until December 2004. The data for the years 1979-95, the period for which the data are the most reliable, show a linear rising trend of 1.8% per annum in the average wave height. The seasonal variation in wave activity follows the variation in wind speed. The monthly mean significant wave height varies from 0.5 m in May-July to 1.3-1.4 m in December-January. No corrections have been made in the analysis to compensate for missing values, for their uneven distribution, or for ice cover.

  • 236.
    Broman, Barry
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Peterson, Carsten
    SMHI.
    Spridningsundersökningar i yttre fjärden Piteå1985Report (Other academic)
    Abstract [sv]

    Sveriges Meteorologiska och Hydrologiska Institut (SMHI) får i september 1984 i uppdrag av SCA, Piteå-Munksund att undersöka utspädnings- och spridningsförhållandena för avloppsvattnet från SCAs Munksundsindustri.

    Under åren 1981 och 1982 utförs strömundersökningar i Yttre fjärden, Piteå, för att med detta som underlag kunna simulera spridningen av avloppsvattnet från Munksundsindustrin (ref nr 8).

    En ändring av utsläppets läge görs i maj 1982 och ytterligare förändringar sker senare under året genom att länsor och strömbildare läggs ut, i syfte att föra avloppsvattnet i ett samlat stråk ut i Piteälvens strömfåra. SMHI rekommenderar, med ledning av strömundersökningarna 1981-82, att en avloppsledning skall dras ut centralt i fjärden med en utsläppsnivå ovan 6 meters djup, dvs ovan språngskiktet.

    Enligt beslut av Länsstyrelsen i Norrbotten i november 1983 (bilaga 1), skall SMHI, i enlighet med Länsstyrelsens anvisningar och på uppdrag av SCA, studera utspädnings- och spridningsförhållandena med hjälp av spårämne.

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  • 237. Brooks, Ian M.
    et al.
    Tjernstrom, Michael
    Persson, P. Ola G.
    Shupe, Matthew D.
    Atkinson, Rebecca A.
    Canut, Guylaine
    Birch, Cathryn E.
    Mauritsen, Thorsten
    Sedlar, Joseph
    SMHI, Research Department, Atmospheric remote sensing.
    Brooks, Barbara J.
    The Turbulent Structure of the Arctic Summer Boundary Layer During The Arctic Summer Cloud-Ocean Study2017In: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 122, no 18, p. 9685-9704Article in journal (Refereed)
  • 238. Browny, Nicola Jane
    et al.
    Nilsson, Johan
    Pemberton, Per
    SMHI, Research Department, Oceanography.
    Arctic Ocean Freshwater Dynamics: Transient Response to Increasing River Runoff and Precipitation2019In: Journal of Geophysical Research - Oceans, ISSN 2169-9275, E-ISSN 2169-9291, Vol. 124, no 7, p. 5205-5219Article in journal (Refereed)
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  • 239. Bruen, M.
    et al.
    Krahe, P.
    Zappa, M.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Vehvilainen, B.
    Kok, K.
    Daamen, K.
    Visualizing flood forecasting uncertainty: some current European EPS platforms-COST731 working group 32010In: Atmospheric Science Letters, ISSN 1530-261X, E-ISSN 1530-261X, Vol. 11, no 2, p. 92-99Article in journal (Refereed)
    Abstract [en]

    Cooperation in Science and Technology (COST) funding allows European scientists to establish international links, communicate their work to colleagues, and promote international research cooperation. COST731 was established to study the propagation of uncertainty from hydrometeorological observations through meteorological and hydrological models to the final flood forecast. Our focus is on how information about uncertainty is presented to the end user and how it is used. COST731 has assembled a number of demonstrations/case studies that illustrate a variety of practical approaches and these are presented here. While there is yet no consensus on how such information is presented, many end users do find it useful. Copyright (C) 2010 Royal Meteorological Society

  • 240. Buizza, Roberto
    et al.
    Poli, Paul
    Rixen, Michel
    Alonso-Balmaseda, Magdalena
    Bosilovich, Michael G.
    Bronnimann, Stefan
    Compo, Gilbert P.
    Dee, Dick P.
    Desiato, Franco
    Doutriaux-Boucher, Marie
    Fujiwara, Masatomo
    Kaiser-Weiss, Andrea K.
    Kobayashi, Shinya
    Liu, Zhiquan
    Masina, Simona
    Mathieu, Pierre-Philippe
    Rayner, Nick
    Richter, Carolin
    Seneviratne, Sonia I.
    Simmons, Adrian J.
    Thepaut, Jean-Noel
    Auger, Jeffrey D.
    Bechtold, Michel
    Berntell, Ellen
    Dong, Bo
    Kozubek, Michal
    Sharif, Khaled
    Thomas, Christopher
    Schimanke, Semjon
    SMHI, Research Department, Oceanography.
    Storto, Andrea
    Tuma, Matthias
    Valisuo, Ilona
    Vaselali, Alireza
    ADVANCING GLOBAL AND REGIONAL REANALYSES2018In: Bulletin of The American Meteorological Society - (BAMS), ISSN 0003-0007, E-ISSN 1520-0477, Vol. 99, no 8, p. ES139-ES144Article in journal (Refereed)
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  • 241. Burchard, Hans
    et al.
    Craig, Peter D.
    Gemmrich, Johannes R.
    van Haren, Hans
    Mathieu, Pierre-Philippe
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Smith, W. Alex M. Nimmo
    Prandke, Hartmut
    Rippeth, Tom P.
    Skyllingstad, Eric D.
    Smyth, William D.
    Welsh, David J. S.
    Wijesekera, Hemantha W.
    Observational and numerical modeling methods for quantifying coastal ocean turbulence and mixing2008In: Progress in Oceanography, ISSN 0079-6611, E-ISSN 1873-4472, Vol. 76, no 4, p. 399-442Article, review/survey (Refereed)
    Abstract [en]

    In this review paper, state-of-the-art observational and numerical modeling methods for small scale turbulence and mixing with applications to coastal oceans are presented in one context. Unresolved dynamics and remaining problems of field observations and numerical simulations are reviewed on the basis of the approach that modern process-oriented studies should be based on both observations and models. First of all, the basic dynamics of surface and bottom boundary layers as well as intermediate stratified regimes including the interaction of turbulence and internal waves are briefly discussed. Then, an overview is given on just established or recently emerging mechanical, acoustic and optical observational techniques. Microstructure shear probes although developed already in the 1970s have only recently become reliable commercial products. Specifically under surface waves turbulence measurements are difficult due to the necessary decomposition of waves and turbulence. The methods to apply Acoustic Doppler Current Profilers (ADCPs) for estimations of Reynolds stresses, turbulence kinetic energy and dissipation rates are under further development. Finally, applications of well-established turbulence resolving particle image velocimetry (PIV) to the dynamics of the bottom boundary layer are presented. As counterpart to the field methods the state-of-the-art in numerical modeling in coastal seas is presented. This includes the application of the Large Eddy Simulation (LES) method to shallow water Langmuir Circulation (LC) and to stratified flow over a topographic obstacle. Furthermore, statistical turbulence closure methods as well as empirical turbulence parameterizations and their applicability to coastal ocean turbulence and mixing are discussed. Specific problems related to the combined wave-current bottom boundary layer are discussed. Finally, two coastal modeling sensitivity studies are presented as applications, a two-dimensional study of upwelling and downwelling and a three-dimensional study for a marginal sea scenario (Baltic Sea). It is concluded that the discussed methods need further refinements specifically to account for the complex dynamics associated with the presence of surface and internal waves. (c) 2008 Elsevier Ltd. All rights reserved.

  • 242. Burton, S. P.
    et al.
    Hair, J. W.
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    Ferrare, R. A.
    Hostetler, C. A.
    Cook, A. L.
    Harper, D. B.
    Berkoff, T. A.
    Seaman, S. T.
    Collins, J. E.
    Fenn, M. A.
    Rogers, R. R.
    Observations of the spectral dependence of linear particle depolarization ratio of aerosols using NASA Langley airborne High Spectral Resolution Lidar2015In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, no 23, p. 13453-13473Article in journal (Refereed)
    Abstract [en]

    Linear particle depolarization ratio is presented for three case studies from the NASA Langley airborne High Spectral Resolution Lidar-2 (HSRL-2). Particle depolarization ratio from lidar is an indicator of non-spherical particles and is sensitive to the fraction of non-spherical particles and their size. The HSRL-2 instrument measures depolarization at three wavelengths: 355, 532, and 1064 nm. The three measurement cases presented here include two cases of dust-dominated aerosol and one case of smoke aerosol. These cases have partial analogs in earlier HSRL-1 depolarization measurements at 532 and 1064 nm and in literature, but the availability of three wavelengths gives additional insight into different scenarios for non-spherical particles in the atmosphere. A case of transported Saharan dust has a spectral dependence with a peak of 0.30 at 532 nm with smaller particle depolarization ratios of 0.27 and 0.25 at 1064 and 355 nm, respectively. A case of aerosol containing locally generated wind-blown North American dust has a maximum of 0.38 at 1064 nm, decreasing to 0.37 and 0.24 at 532 and 355 nm, respectively. The cause of the maximum at 1064 nm is inferred to be very large particles that have not settled out of the dust layer. The smoke layer has the opposite spectral dependence, with the peak of 0.24 at 355 nm, decreasing to 0.09 and 0.02 at 532 and 1064 nm, respectively. The depolarization in the smoke case may be explained by the presence of coated soot aggregates. We note that in these specific case studies, the linear particle depolarization ratio for smoke and dust-dominated aerosol are more similar at 355 nm than at 532 nm, having possible implications for using the particle depolarization ratio at a single wavelength for aerosol typing.

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  • 243.
    Bärring, Lars
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Berlin, Mats
    Andersson Gull, Bengt
    Tailored climate indices for climate-proofing operational forestry applications in Sweden and Finland2017In: International Journal of Climatology, ISSN 0899-8418, E-ISSN 1097-0088, Vol. 37, no 1, p. 123-142Article in journal (Refereed)
  • 244.
    Bärring, Lars
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Christensen, Jens
    Déqué, Michel
    Giorgi, Filippo
    Jones, Colin
    SMHI, Research Department, Climate research - Rossby Centre.
    Jones, Richard
    Laprise, René
    Rummukainen, Markku
    SMHI, Research Department, Climate research - Rossby Centre.
    von Storch, Hans
    Synthesis of Workshop2005In: Extended abstracts of a WMO/WCRP-sponsored Regional-Scale Climate Modelling Workshop : high-resolution climate modelling : assessment, added value and applications, Lund, Sweden, 29 March-2 April 2004 / [ed] Bärring, Lars; René, Laprise, Department of Physical Geography & Ecosystem Analysis, Lund University, Sweden , 2005, p. 18-25Conference paper (Other academic)
  • 245.
    Bärring, Lars
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Fortuniak, Krzysztof
    Multi-indices analysis of southern Scandinavian storminess 1780-2005 and links to interdecadal variations in the NW Europe-North Sea region2009In: International Journal of Climatology, ISSN 0899-8418, E-ISSN 1097-0088, Vol. 29, no 3, p. 373-384Article in journal (Refereed)
    Abstract [en]

    Extra-tropical cyclone frequency and intensity are Currently under intense scrutiny because of the destruction recent windstorms have brought to Europe, and because they are a major meridional heat transport mechanism that may respond to differential latitudinal warming trends. Several studies using reanalysis data covering the second half of the 20th century Suggest increasing storm intensity in the northeastern Atlantic and European sector. Fewer analyses cover a longer time period but show different trends or point towards the dominance of interdecadal variability instead of ally clear trends. Hence, it is relevant to analyse cyclone variability over as long a period as possible. In this Study, we analyse interdecadal variability in cyclone activity over northwestern Europe back to AD 1780 by combining information from eight storminess indices applied in all Eulerian framework. These indices, including four new approaches towards gauging cyclone activity, use the series of thrice-daily sea level pressure observations at Lund and Stockholm. We find pronounced interdecadal variability in cyclonic activity but no significant overall consistent long-term trend. The major interdecadal-scale variability common to all indices is in good agreement with geostrophic wind reconstructions for NE Atlantic and NW Europe, and with variations in the North Atlantic oscillation (NAO). Our results show that the reanalysis studies cover a time period chiefly coinciding with a marked, but not exceptional in our 225-year perspective, positive variation in the regional cyclone activity that has more recently reversed. Because of the interdecadal variations, a near-centennial time perspective is needed when analysing variations in extra-tropical cyclone activity and the associated weather conditions over northwestern Europe. Copyright (C) 2009 Royal Meteorological Society

  • 246.
    Bärring, Lars
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Holt, Tom
    Linderson, Maj-Lena
    Radziejewski, Madej
    Moriondo, Marco
    Palutikof, Jean P.
    Defining dry/wet spells for point observations, observed area averages, and regional climate model gridboxes in Europe2006In: Climate Research (CR), ISSN 0936-577X, E-ISSN 1616-1572, Vol. 31, no 1, p. 35-49Article in journal (Refereed)
    Abstract [en]

    A new method for optimising threshold values of dry/wet spells is evaluated. A set of indices is used to find the best threshold giving good correspondence between the frequency of dry/wet spells in Hadley Centre regional model (HadRM3) output, reference observations with predetermined thresholds, and area-averaged observations. The analyses focus on selected model gridboxes in 3 different European climate regimes (Sweden, UK, Italy), where station data are available from several locations. In addition, a pan-European analysis using the European Climate Assessment (ECA) dataset is carried out. Generally, there is good agreement between point observations and the corresponding area average using the common thresholds of 0.1 or 1.0 mm with observational data. Applying the optimal thresholds on the model output is important, as it typically results in substantially better agreement between the simulated and observed series of dry/wet days. The fitted optimal pan-European dry/wet threshold is (1) 0.47 or 0.15 mm, depending on model version, for the observed point data threshold of 0.1 mm, and (2) 1.2 or 0.56 mm, depending on model version, for the threshold of 1.0 mm.

  • 247.
    Bärring, Lars
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Jonsson, P
    Achberger, C
    Ekstrom, M
    Alexandersson, Hans
    SMHI.
    The Lund instrumental record of meteorological observations: Reconstruction of monthly sea-level pressure 1780-19971999In: International Journal of Climatology, ISSN 0899-8418, E-ISSN 1097-0088, Vol. 19, no 13, p. 1427-1443Article in journal (Refereed)
    Abstract [en]

    The reconstructed surface air pressure series from Lund, southern Sweden, covers the period 1780-1997 and comprises mon than 234000 valid observations (three observations per day), i.e. > 98% of all possible observation occasions. For the Early Instrumental Period (EIP; 1780-1860) data were digitised from the original records. For most of the Modern Instrumental Period (MIP; 1861-) a series was compiled from various databases containing instrument corrected data. During EIP, the series of raw monthly means show several substantial inhomogeneities. With the aid of a detailed reconstruction of the station history, it was possible to remove almost all inhomogeneities during EIP by applying the correct instrument corrections (for barometer temperature, to standard gravity and to mean sea-level pressure) to the series of original observations. In particular, corrections for the temperature and altitude of the barometer eliminated several inhomogeneities. A prerequisite for applying these corrections is the availability of high-resolution data (actual raw observations or daily averages). Further homogenisation was attained by intercomparison of the monthly mean pressure with acknowledged homogeneous series (mainly the UKMO monthly grid, station records from Copenhagen and Edinburgh). Statistical tests of homogeneity showed that no substantial inhomogeneities remain in the final version. The modern part of the final monthly pressure series largely follows that of the southern Baltic Sea region. Furthermore, it shows relatively high pressure during spring (MAM) in the period 1780-1820, which was paralleled by severe wind erosion in southern Scandinavia during this time. Relatively high pressure throughout the year is also notable during a period of precipitation deficit in 1970s. Copyright (C) 1999 Royal Meteorological Society.

  • 248.
    Bärring, Lars
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Persson, Gunn
    SMHI, Professional Services.
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Samuelsson, Patrick
    SMHI, Research Department, Climate research - Rossby Centre.
    Evaluation of climate extremes in transient runs with the new Rossby Centre regional atmospheric model.2006In: Abstracts of the contributions of the EGU General Assembly 2006, EGU06-A-10110, 2006Conference paper (Other academic)
  • 249.
    Bärring, Lars
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Strandberg, Gustav
    SMHI, Research Department, Climate research - Rossby Centre.
    Does the projected pathway to global warming targets matter?2018In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 13, no 2, article id 024029Article in journal (Refereed)
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  • 250.
    Bärring, Lars
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    von Storch, H
    Scandinavian storminess since about 18002004In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 31, no 20, article id L20202Article in journal (Refereed)
    Abstract [en]

    We study the history of storminess in Northern Europe, as derived from local pressure observations in Lund since 1780 and Stockholm since 1820 ( Sweden). At both stations barometer readings were made three times per day, morning, midday and evening, and after about 1850 at fixed observation hours. We use four common storminess indices: annual number of deep lows ( p < 980 hPa), the annual 95th and 99th percentile of pressure changes between two observations, and the annual number of fast absolute pressure changes (\&UDelta;p\/&UDelta;t > 16 hPa/12 h). It turns out that the 1980' s - mid 1990' s were a period of enhanced storminess, mainly seen in the Stockholm record, but his period is within the natural variability of the records. Thus, there are no robust signs of any long-term trend in the storminess indices. Storminess is during the entire historical period remarkably stable, with no systematic change and little transient variability.

2345678 201 - 250 of 1769
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