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  • 201. Bjorkman, Christer
    et al.
    Kindvall, Oskar
    Hoglund, Solveig
    Lilja, Anna
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Bärring, Lars
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Eklund, Karin
    High Temperature Triggers Latent Variation among Individuals: Oviposition Rate and Probability for Outbreaks2011Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, nr 1, artikel-id e16590Artikel i tidskrift (Refereegranskat)
    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.

  • 202. 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 project2006Ingår i: African Journal of Marine Science, ISSN 1814-232X, E-ISSN 1814-2338, Vol. 28, nr 2, s. 365-369Artikel i tidskrift (Refereegranskat)
    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.

  • 203. Blazica, V.
    et al.
    Gustafsson, Nils
    SMHI, Forskningsavdelningen, Meteorologi.
    Zagar, N.
    The impact of periodization methods on the kinetic energy spectra for limited-area numerical weather prediction models2015Ingår i: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 8, nr 1, s. 87-97Artikel i tidskrift (Refereegranskat)
    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.

  • 204. Blenckner, T
    et al.
    Omstedt, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Rummukainen, Markku
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    A Swedish case study of contemporary and possible future consequences of climate change on lake function2002Ingår i: Aquatic Sciences, ISSN 1015-1621, E-ISSN 1420-9055, Vol. 64, nr 2, s. 171-184Artikel i tidskrift (Refereegranskat)
    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.

  • 205. Bloeschl, Guenter
    et al.
    Hall, Julia
    Parajka, Juraj
    Perdigao, Rui A. P.
    Merz, Bruno
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    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 floods2017Ingår i: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 357, nr 6351, s. 588-590Artikel i tidskrift (Refereegranskat)
  • 206. Bloeschl, Guenter
    et al.
    Hall, Julia
    Viglione, Alberto
    Perdigao, Rui A. P.
    Parajka, Juraj
    Merz, Bruno
    Lun, David
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    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 floods2019Ingår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 573, nr 7772, s. 108-+Artikel i tidskrift (Refereegranskat)
    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.

  • 207. 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, Forskningsavdelningen, Hydrologi.
    Aryal, Santosh K.
    Baker, Victor
    Bardsley, Earl
    Barendrecht, Marlies H.
    Bartosova, Alena
    SMHI, Forskningsavdelningen, Hydrologi.
    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 perspective2019Ingår i: Hydrological Sciences Journal, ISSN 0262-6667, E-ISSN 2150-3435, Vol. 64, nr 10, s. 1141-1158Artikel i tidskrift (Refereegranskat)
  • 208. Blom, Eva-Lotta
    et al.
    Kvarnemo, Charlotta
    Dekhla, Isabelle
    Schöld, Sofie
    SMHI, Samhälle och säkerhet.
    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 care2019Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, artikel-id 5494Artikel i tidskrift (Refereegranskat)
  • 209.
    Bodin, Svante
    SMHI, Forskningsavdelningen.
    Development on an unsteady atmospheric boundary layer model1974Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    För att tjäna som ett hjälpmedel för lokalprognoser och flygplatsprognoser har vid SMHI startats ett arbete med att utveckla en atmosfärisk gränsskiktsmodell. Modellen ska kopplas till en storskalig, numerisk prognosmodell som förser den med variabla randvärden för vind, temperatur och fuktighet. Istället för att använda de vanliga Ekman-ekvationerna har använts en metod utvecklad av L N Gutman (1969) fär att härleda gränsskiktsekvationerf ör en en-dimensionell modell. Dessa ekvationer har fördelen att de filtrerar bort de tröghet-diffusionssvängningar som är närvarande i ett Ekman-skikt när den geostrofiska vinden varierar i tiden.

    En enkel, torr version av modellen har utnyttjats för att studera effekten av variationen i tiden av bakgrundsvinden (den storskaliga vinden). En turbulent utbyteskoefficient, som är grundad på Manin & Obukhovs similaritetsteori och som använder Blackadars reduktion av blandningslängden, har använts i dessa experiment. Crank-Nicolson-metoden har utnyttjats vid den numeriska tidsintegrationen. Beräkningsresultaten visar att det blir stora skillnader mellan vinden beräknad ur den icke-stationära modellen och motsvarande stationära lösningar. Detta visas med vindhodografer vid olika tidpunkter samt med figurer med friktionshastigheten, u*, och tvärisobara vinkeln som funktion av tiden. Slutligen har också en jämförelse gjorts mellan två olika analytiska lösningar samt en finit differenslösning, från vilka värmeflödena vid jordytan, beroende på värmeledning, i marken som funktion av tiden har beräknats.

  • 210.
    Bodin, Svante
    SMHI, Forskningsavdelningen.
    En numerisk prognosmodell för det atmosfäriska gränsskiktet, grundad på den turbulenta energiekvationen1979Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Intresset för gränsskiktsmodeller har vuxit markant under senare år . Vid SMHI planeras tillämpningar av gränsskiktsmodeller inom lokalprognosområdet, speciellt vid flygplatser, i studier av luftföroreningars spridning och inom  vindenergiprogrammet.

    I denna rapport presenteras en en-dimensionell numerisk gränsskiktsmodell och resultat från simuleringar av australienska och finländska gränsskiktsdata diskuteras relativt ingående. Modellen, som utgör första steget mot en tredimensionell modell, bygger på ideer om gränsskiktsmodellering framlagda av Gutman. För att parameterisera turbulensen i gränsskiktet utnyttjas den turbulenta energiekvationen. En enkel skalanalys av rörelseekvationerna visar att ett gridavstånd på mindre än 20 km måste användas i en tredimensionell modell för att man ska uppnå fördelar gentemot en endimensionell modell, i vilken fullständigare fysikaliska beskrivningar kan inkluderas.

    Modellen i denna rapport innehåller också kondensationsprocesser, dvs dimma och moln, och ett komplett paket för strålningsberäkningar. En prognosekvation för marktemperaturen finns härledd och används i samband med en enkel modell för markvatten.

    I den numeriska lösningen utnyttjas Laasonens metod, en variant av Crank-Nicolson, för tidsintegrationen. Den vertikala koordinaten har transformerats log-lineärt för att ge bättre upplösning nära marken. 35 gridpunkter används för att upplösa gränsskiktet upp till 2000 m. Ett tidssteg om 4 minuter har använts i de flesta simuleringarna.

    Två versioner av modellen, en Gutman-version och en vanlig "Ekman"-version, har testats utifrån dag 33 och 34 av Wangara data. De två första versionerna har jämförts sinsemellan medan Ekman-versionen också har jämförts med Yamada & Mellors (1975) mycket omfattande simuleringar. Resultaten visar att när det gäller vinden är Ekmanversionen överlägsen Gutman-versionen. Temperaturen å andra sidan simuleras mycket bra av båda versionerna. Jämförelsen med Yamada & Mellor utfaller till fördel för den här beskrivna modellen.

    Vissa framtida förbättringar diskuteras avslutningsvis. Modellen planeras också att testas operationellt på Arlanda flygplats inom en nära framtid.

  • 211. Boergel, Florian
    et al.
    Frauen, Claudia
    Neumann, Thomas
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Impact of the Atlantic Multidecadal Oscillation on Baltic Sea Variability2018Ingår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 45, nr 18, s. 9880-9888Artikel i tidskrift (Refereegranskat)
  • 212.
    Bojarova, Jelena
    et al.
    SMHI, Forskningsavdelningen, Meteorologi.
    Gustafsson, Nils
    SMHI, Forskningsavdelningen, Meteorologi.
    Relevance of climatological background error statistics for mesoscale data assimilation2019Ingår i: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 71, nr 1, artikel-id 1615168Artikel i tidskrift (Refereegranskat)
  • 213. Bojarova, Jelena
    et al.
    Gustafsson, Nils
    SMHI, Forskningsavdelningen, Meteorologi.
    Johansson, Åke
    SMHI, Forskningsavdelningen, Meteorologi.
    Vignes, Ole
    The ETKF rescaling scheme in HIRLAM2011Ingår i: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 63, nr 3, s. 385-401Artikel i tidskrift (Refereegranskat)
    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.

  • 214. Bolin, Karl
    et al.
    Almgren, Martin
    Olsson, Esbjörn
    SMHI, Forskningsavdelningen, Meteorologi.
    Karasalo, Ilkka
    Long term estimations of low frequency noise levels over water from an off-shore wind farm2014Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 135, nr 3, s. 1106-1114Artikel i tidskrift (Refereegranskat)
    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.

  • 215. Bonaduce, Antonio
    et al.
    Staneva, Joanna
    Behrens, Arno
    Bidlot, Jean-Raymond
    Wilcke, Renate
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Wave Climate Change in the North Sea and Baltic Sea2019Ingår i: Journal of Marine Science and Engineering, E-ISSN 2077-1312, Vol. 7, nr 6, artikel-id 166Artikel i tidskrift (Refereegranskat)
  • 216. Boone, Aaron
    et al.
    Samuelsson, Patrick
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Gollvik, Stefan
    SMHI, Forskningsavdelningen, Meteorologi.
    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 description2017Ingår i: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 10, nr 2, s. 843-872Artikel i tidskrift (Refereegranskat)
  • 217.
    Borenäs, Karin
    et al.
    SMHI, Samhälle och säkerhet.
    Hietala, R.
    Laanearu, J.
    Lundberg, P.
    Some estimates of the Baltic deep-water transport through the Stolpe trench2007Ingår i: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 59, nr 2, s. 238-248Artikel i tidskrift (Refereegranskat)
    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.

  • 218.
    Borenäs, Karin
    et al.
    SMHI, Samhälle och säkerhet.
    Lake, Irene
    Lundberg, P A
    On the intermediate water masses of the Faroe-Bank Channel overflow2001Ingår i: Journal of Physical Oceanography, ISSN 0022-3670, E-ISSN 1520-0485, Vol. 31, nr 7, s. 1904-1914Artikel i tidskrift (Refereegranskat)
    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.

  • 219.
    Borenäs, Karin
    et al.
    SMHI, Samhälle och säkerhet.
    Lundberg, P
    The Faroe-Bank channel deep-water overflow2004Ingår i: Deep-sea research. Part II, Topical studies in oceanography, ISSN 0967-0645, E-ISSN 1879-0100, Vol. 51, nr 4-5, s. 335-350Artikel i tidskrift (Refereegranskat)
    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.

  • 220. Borrego, C.
    et al.
    Amorim, Jorge Humberto
    SMHI, Forskningsavdelningen, Luftmiljö.
    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 estimates2016Ingår i: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 131, s. 341-351Artikel i tidskrift (Refereegranskat)
    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.

  • 221. Borsche, M.
    et al.
    Kaiser-Weiss, A. K.
    Undén, Per
    SMHI, Forskningsavdelningen, Meteorologi.
    Kaspar, F.
    Methodologies to characterize uncertainties in regional reanalyses2015Ingår i: Advances in Science and Research, ISSN 1992-0628, E-ISSN 1992-0636, Vol. 12, s. 207-218Artikel i tidskrift (Refereegranskat)
    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.

  • 222.
    Bosshard, Thomas
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Carambia, M.
    Goergen, K.
    Kotlarski, S.
    Krahe, P.
    Zappa, M.
    Schaer, C.
    Quantifying uncertainty sources in an ensemble of hydrological climate-impact projections2013Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 49, nr 3, s. 1523-1536Artikel i tidskrift (Refereegranskat)
    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.

  • 223.
    Bosshard, Thomas
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Kotlarski, Sven
    Zappa, Massimiliano
    Schaer, Christoph
    Hydrological Climate-Impact Projections for the Rhine River: GCM-RCM Uncertainty and Separate Temperature and Precipitation Effects2014Ingår i: Journal of Hydrometeorology, ISSN 1525-755X, E-ISSN 1525-7541, Vol. 15, nr 2, s. 697-713Artikel i tidskrift (Refereegranskat)
    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.

  • 224. Boucher, Etienne
    et al.
    Nicault, Antoine
    Arseneault, Dominique
    Begin, Yves
    Karami, Mehdi Pasha
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Decadal Variations in Eastern Canada's Taiga Wood Biomass Production Forced by Ocean-Atmosphere Interactions2017Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, artikel-id 2457Artikel i tidskrift (Refereegranskat)
  • 225. Bourgeois, Quentin
    et al.
    Ekman, Annica M. L.
    Renard, Jean-Baptiste
    Krejci, Radovan
    Devasthale, Abhay
    SMHI, Forskningsavdelningen, Atmosfärisk fjärranalys.
    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?2018Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 18, nr 10, s. 7709-7720Artikel i tidskrift (Refereegranskat)
  • 226. Bowling, L C
    et al.
    Lettenmaier, D P
    Nijssen, B
    Graham, Phil
    SMHI, Forskningsavdelningen, Klimatforskning - 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, Forskningsavdelningen, Klimatforskning - 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 intercomparisons2003Ingår i: Global and Planetary Change, ISSN 0921-8181, E-ISSN 1872-6364, Vol. 38, nr 1-2, s. 1-30Artikel i tidskrift (Refereegranskat)
    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.

  • 227. Bowling, Laura
    et al.
    Lettenmaier, Dennis
    Graham, Phil
    SMHI, Affärsverksamhet.
    Land-surface parameterizations in northern regions: preliminary results from the PILPS 2e model intercomparison.2001Ingår i: Third study conference on BALTEX / [ed] Jens Meywerk, 2001, s. 25-26Konferensbidrag (Övrigt vetenskapligt)
  • 228. Brandefelt, J.
    et al.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Naslund, J. -O
    Strandberg, Gustav
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Voelker, A. H. L.
    Wohlfarth, B.
    A coupled climate model simulation of Marine Isotope Stage 3 stadial climate2011Ingår i: Climate of the Past, ISSN 1814-9324, E-ISSN 1814-9332, Vol. 7, nr 2, s. 649-670Artikel i tidskrift (Refereegranskat)
  • 229. Brandefelt, Jenny
    et al.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Näslund, Jens-Ove
    Strandberg, Gustav
    Voelker, Antje
    Wohlfarth, Barbara
    The importance of equilibration in glacial climate simulations2010Ingår i: Geophysical Research Abstracts, 2010, Vol. 12, artikel-id EGU2010-10736Konferensbidrag (Refereegranskat)
  • 230.
    Brandt, Maja
    SMHI, Samhälle och säkerhet.
    Areella snöstudier1986Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Den areella variationen hos ett snötäcke påverkas av mångafaktorer. De meteorologiska förhållandena - främst temperaturoch fuktighet - när snön faller, styr snöns ursprungligadensitet och djup. Vind under och efter snötillfället förflyttarsnön. Den ansamlas i svackor och längs hinder, texlängs skogsgränser, och eroderas på utsatta platser, såsomryggar. Snöförluster orsakade av smältning och avdunstningpåverkar även snöackumulationen.

  • 231.
    Brandt, Maja
    SMHI, Samhälle och säkerhet.
    Bestämning av optimalt klimatstationsnät för hydrologiska prognoser1987Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Det är lätt att avfärda dåliga prognosresultat med att klimatstationsnätet är för glest för att man skall kunna bestämma vinternederbörden korrekt. För att testa antalet behövliga temperatur- och nederbördsstationer för olika typer av områden har vi därför prövat att ändra antalet temperatur- resp. nederbördsstationer och studerat hur det påverkar simuleringarnas precision.Studien har finansierats av Vattenregleringsföretagens samarbetsorgan(VASO).

  • 232.
    Brandt, Maja
    SMHI, Samhälle och säkerhet.
    GENERATION, TRANSPORT AND DEPOSITION OF SUSPENDED AND DISSOLVED MATERIAL - EXAMPLES FROM SWEDISH RIVERS1990Ingår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 72, nr 3-4, s. 273-283Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Soil erosion, sediment transport and deposition in river systems in Sweden are discussed. The database consists of observations from a research project and from the Swedish network for the measurement of sediment transport. Examples are given from measurements in small plots, and from river basins of different sizes and characteristics. Effects of hydrological regime, of deposition in lakes, and of geology and human impact are illustrated. It was found that observations of erosion losses in index plots cannot easily be extrapolated to large areas, and that trends of transport most likely reflect trends in runoff.

  • 233.
    Brandt, Maja
    SMHI, Samhälle och säkerhet.
    Human impacts and weather-dependent effects on water balance and water quality in some Swedish river basins1990Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The weather has a great effect on the water balance and, indirectly, affects water quality of river systems. At the same tirne, man-made changes in the Iandscape and other human activities have a great impact. To be able to distinguish the human irnpacts from the effects of natura! weather fluctuations we need observations and measurements but also analysis tools.

    In this thesis the PULSE and HBV hydrological models have been used as the analysis tools. Examples are given from forest management, in particular clearcuning, drainage and biomass increase, and from mining and agricultural activities. The models include conceptual descriptions of the most significant hydrological processes and are capable of coping with. weather-dependent fluctuations. Observed air temperature, precipitation and an estimate of the potential evapotranspiration are input data to the models.

    Simple hydrochemical and nitrogen leaching subroutines have been Iinked to the PULSE water balance model.These subroutines have been used to quantify weather-dependent and human effects on pH downstream from a mine tailings deposit and on nitrogen Ieaching from different non-point sources, especially from arable land.

    The applications illustrate the advantage of this type of model for analysis of man-made irnpacts and short-term climatological fluctuations. As the models are restricted to stationary conditions they cannot be used for forecasting of long-term changes due to changes in atmospheric deposition, land use or climate, unless the local effects of these changes are known. Other methods of analysing effects of man-made changes have also been tested, such as conventional comparative investigations, regression analysis and trend analysis. The use of these methods is exemplified by an analysis of human effects on erosion and sediment transport. It was found to be much more difficult to quantify effects with these sirnpler methods

  • 234.
    Brandt, Maja
    SMHI, Samhälle och säkerhet.
    Sedimenttransport i svenska vattendrag exempel från 1967-19941996Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    "Sedimenttransport i svenska vattendrag exempel från 1967-1994" är framtagen inom Analysenheten på Affärsområde Samhälle vid SMHI.

    Många års mätning inom sedimenttransportnätet ligger till grunden för denna bearbetning.

    Månads- och årsvärden på halter och transporter finns bearbetade och lagrade för alla stationer. Dessa kan beställas från SMHI. I denna rapport redovisas delar av detta material.

  • 235.
    Brandt, Maja
    SMHI, Samhälle och säkerhet.
    SIMULATION OF RUNOFF AND NITRATE TRANSPORT FROM MIXED BASINS IN SWEDEN1990Ingår i: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 21, nr 1, s. 13-34Artikel i tidskrift (Refereegranskat)
  • 236.
    Brandt, Maja
    SMHI, Samhälle och säkerhet.
    Skogens inverkan på vattenbalansen1992Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Virkesmängden i Sveriges skogar har ökat under 1900-talet och i första hand beror det på ökad skogsproduktion. I södra Sverige har även skogsrnarksarealen ökat något. Eftersom träd tar upp vatten från marken, har det diskuterats om detta innebär att avdunstningen ökat och i sin tur avrinningen minskat. Frågan har analyserats dels genom beräkning av differensen mellan nederbörd (omräknad till areell och höjdkorrigerad nederbörd) och avrinning, dvs ett relativt mått på evapotranspirationen, för ett antal avrinningsområden i Sverige, och dels genom modellsimulering med HBVmodellen från 1930-talet och framåt.

    Differensberäkningen utifrån den uppmätta nederbörden och avrinningen visar att våta år medför inte bara hög avrinning utan även ofta något högre evapotranspiration än torra år. Man kan inte se några tydliga förändringar i evapotranspirationen i någon av de undersökta områdena mer än mindre upp- och nergångar, som troligen mest beror på klimatets fluktuationer.

    Indata till modellen är nederbörd och lufttemperatur. Modellen tar hand om de väderberoende fluktuationerna och gör det är lättare att skilja klimatförändringar från effekten av ändrad markanvändning. Inte heller den analysen visar några klara trender i evapotranspirationen och avrinningen. Eventuella förändringar försvinner i det brus som uppstår av ofullständiga indata (ett glest nederbördsnät på grund av kravet på homogena långa serier) och på de förenklingar av naturen som ändå sker i modellen. Studien tyder alltså på att det inte skett några tydligt påvisbara förändringar av evapotranspirationen och avrinningen på grund av ökad skogstillväxt.

  • 237.
    Brandt, Maja
    SMHI, Samhälle och säkerhet.
    Snömätning med georadar och snötaxeringar i övre Luleälven1991Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Snömätning med flygburen georadarutrustning (i helikopter) har utförts längs fasta linjer i övre Luleälvens tillrinningsområde i april under åren 1986 till 1990. I prognosområdena Suorva, Parki och Tjaktjajaure, som domineras av kalfjäll och där nederbördsstationsnätet är mycket glest, visar de fem årens mätningar, att en uppdatering av HBV-modellens snömagasin utifrån georadarmätningarna kan förbättra prognosutfallet. För skogsområdena Porjus och Letsi, som har ett mer representativt nederbördsstationsnät och bättre prognosutfall, är det svårare att förbättra prognoserna.

  • 238.
    Brandt, Maja
    et al.
    SMHI, Samhälle och säkerhet.
    Bergström, Sten
    SMHI, Forskningsavdelningen, Hydrologi.
    INTEGRATION OF FIELD DATA INTO OPERATIONAL SNOWMELT-RUNOFF MODELS1994Ingår i: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 25, nr 1-2, s. 101-112Artikel i tidskrift (Refereegranskat)
    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.

  • 239.
    Brandt, Maja
    et al.
    SMHI, Samhälle och säkerhet.
    Bergström, Sten
    SMHI, Forskningsavdelningen, Hydrologi.
    Gardelin, Marie
    SMHI, Affärsverksamhet.
    MODELING THE EFFECTS OF CLEARCUTTING ON RUNOFF - EXAMPLES FROM CENTRAL SWEDEN1988Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 17, nr 5, s. 307-313Artikel i tidskrift (Refereegranskat)
  • 240.
    Brandt, Maja
    et al.
    SMHI, Samhälle och säkerhet.
    Bergström, Sten
    SMHI, Forskningsavdelningen, Hydrologi.
    Gardelin, Marie
    SMHI, Affärsverksamhet.
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Modellberäkning av extrem effektiv nederbörd1987Rapport (Övrigt vetenskapligt)
    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.

  • 241.
    Brandt, Maja
    et al.
    SMHI, Samhälle och säkerhet.
    Bergström, Sten
    SMHI, Forskningsavdelningen, Hydrologi.
    Sandén, Per
    SMHI, Forskningsavdelningen, Hydrologi.
    ENVIRONMENTAL IMPACTS OF AN OLD MINE TAILINGS DEPOSIT - MODELING OF WATER-BALANCE, ALKALINITY AND PH1987Ingår i: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 18, nr 4-5, s. 291-300Artikel i tidskrift (Refereegranskat)
  • 242.
    Brandt, Maja
    et al.
    SMHI, Samhälle och säkerhet.
    Ehlert, Kurt
    SMHI, Samhälle och säkerhet.
    Avrinningen från Sverige till omgivande hav1996Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Avrinningen från Sverige till omgivande hav har beräknats från 1931 och framåt dels utifrån direkta vattenföringsbestämningar i större vattendrag och dels genom uppskattningar av vattenflödet för kustområden och små avrinningsområden med hjälp av referensstationer. Uppmätta vattenföringsuppgifter finns från 86% av landarealen. Beräkningarna är lagrade som månads- och årsvärden för alla huvudvattendrag, som mynnar i havet, samt för alla kustområden mellan dessa. Beräkningar finns för 265 områden.Grundvattenflöde som ej förs ut med vattendragen har uppskattats till 0,4 promille av totala avrinningen från Sverige.I rapporten presenteras i tabeller 30-årsmedelvärden och månadsmedelvärden för de större floder vid mynningen och för större kustområden inkluderat mindre vattendrag för perioden 1931-1990. Dessutom redovisas långtidsförändringar, trender och säsongsvariationer samt tillrinningen till havet längs olika kuststräckor.

  • 243.
    Brandt, Maja
    et al.
    SMHI, Samhälle och säkerhet.
    Grahn, Gun
    SMHI.
    Avdunstning och avrinningskoefficient i Sverige 1961-1990: Beräkningar med HBV-modellen1998Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Världsmeteorologiska organisationen (WMO) har fastställt att statistiska parametrar, som används för klimatbeskrivningar, skall beräknas för sk normalperioder orn 30 år, såsom 1931-1960, 1961-1990. I Sveriges Nationalatlas (SNA 1995) redovisas ett stort antal kartor för olika parametrar (nederbörd, avrinning, avdunstning, temperatur, snödjup osv) för perioden 1961-1990. Avrinningskartan i SNA togs fram med hjälp av HBV-modellen.Modellen beskriver vattnets kretslopp från nederbörd, snöackumulation till snösmältning, avdunstning, buffring i marken, grundvattenbildning och avrinning på daglig basis, vilket gör det möjligt att plocka ut mer resultat för fler parametrar än bara avrinningen både i rummet och tiden.

    I denna rapport har avdunstningen och avrinningskoefficienter i Sverige närmare studerats utifrån de körningar som gjorts för perioden 1961-1990. Diagrammen och kartorna i rapporten är av översiktlig natur och hänsyn måste tas till det vid utnyttjandet. Kartorna är inte lämpadeför detaljplanering eller vid studier av korta delperioder.

  • 244. 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, Forskningsavdelningen, Hydrologi.
    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 use2009Ingår i: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 32, nr 2, s. 129-146Artikel i tidskrift (Refereegranskat)
    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.

  • 245. Brigode, Pierre
    et al.
    Brissette, Francois
    Nicault, Antoine
    Perreault, Luc
    Kuentz, Anna
    SMHI, Samhälle och säkerhet.
    Mathevet, Thibault
    Gailhard, Joel
    Streamflow variability over the 1881-2011 period in northern Quebec: comparison of hydrological reconstructions based on tree rings and geopotential height field reanalysis2016Ingår i: Climate of the Past, ISSN 1814-9324, E-ISSN 1814-9332, Vol. 12, nr 9, s. 1785-1804Artikel i tidskrift (Refereegranskat)
  • 246.
    Bringfelt, Bertil
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Räisänen, Jouni
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Gollvik, Stefan
    Meterologi.
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Graham, Phil
    SMHI, Affärsverksamhet.
    Ullerstig, Anders
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    The land surface treatment for the Rossby Centre Regional Atmospheric Climate Model - version 2 (RCA2)2001Rapport (Övrigt vetenskapligt)
    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.

  • 247.
    Bringfelt, Björn
    SMHI.
    An evapotranspiration model using SYNOP weather observations in the Penman-Monteith equation1998Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This work was initiated in order to improve the evapotranspiration data used in the HBV model. Evapotranspiration is calculated consecutively by the Penman-Monteith equation using three-hourly SYNOP observations transformed to values of net radiation, water vapour deficit and data necessary for evaluating aerodynamical resistance and surf ace resistance. Transpiration, rainfall interception and a simple treatment of winter evaporation are included. Soil moisture is used for calculating the surface resistance and it is updated three-hourly with the soil moisture accounting routine of the HBV model regarding the contributions from rainfall and snow melt. Then soil moisture is reduced due to total evapotranspiration.

    Two main parts have been developed and are described here:1. A program for interpolation of missing SYNOP observations and2. The evapotranspiration model.Evapotranspiration is calculated for six SYNOP stations used in the HBV model. Using literature parameter values for open land and forest, the calculated transpiration, interception evaporation and snow evaporation are found to assign reasonable values. Only limited tests against measured evapotranspiration have been made, such as some comparisons with winter data from the NOPEX main site in Norunda north of Uppsala. A comparison is made with evapotranspiration data obtained from calibrations of the HBV model. The performance of the evaporation values in the HBV model remains to be tested. 

  • 248.
    Bringfelt, Björn
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    PARTICLE CONCENTRATION MODEL IN A SMALL TOWN STREET BASED ON RECEPTOR STUDIES1987Ingår i: Journal of Aerosol Science, ISSN 0021-8502, E-ISSN 1879-1964, Vol. 18, nr 6, s. 841-844Artikel i tidskrift (Refereegranskat)
  • 249.
    Bringfelt, Björn
    et al.
    SMHI.
    Backström, Hans
    SMHI, Affärsverksamhet.
    Kindell, Sven
    SMHI, Affärsverksamhet.
    Omstedt, Gunnar
    SMHI, Forskningsavdelningen, Luftmiljö.
    Persson, Christer
    SMHI, Forskningsavdelningen, Luftmiljö.
    Ullerstig, Anders
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Calculations of PM-10 concentrations in Swedish cities - Modelling of inhalable particles1997Rapport (Övrigt vetenskapligt)
  • 250.
    Bringfelt, Björn
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Heikinheimo, M
    Gustafsson, Nils
    SMHI, Forskningsavdelningen, Meteorologi.
    Perov, Veniamin
    SMHI, Forskningsavdelningen, Meteorologi.
    Lindroth, A
    A new land-surface treatment for HIRLAM - comparisons with NOPEX measurements1999Ingår i: Agricultural and Forest Meteorology, ISSN 0168-1923, E-ISSN 1873-2240, Vol. 98-9, s. 239-256Artikel i tidskrift (Refereegranskat)
    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.

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