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  • 201. 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.

  • 202. 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)
  • 203. 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)
  • 204.
    Borenäs, Karin
    et al.
    SMHI, Core Services.
    Hietala, R.
    Laanearu, J.
    Lundberg, P.
    Some estimates of the Baltic deep-water transport through the Stolpe trench2007In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 59, no 2, p. 238-248Article in journal (Refereed)
    Abstract [en]

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

  • 205.
    Borenäs, Karin
    et al.
    SMHI, Core Services.
    Lake, Irene
    Lundberg, P A
    On the intermediate water masses of the Faroe-Bank Channel overflow2001In: Journal of Physical Oceanography, ISSN 0022-3670, E-ISSN 1520-0485, Vol. 31, no 7, p. 1904-1914Article in journal (Refereed)
    Abstract [en]

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

  • 206.
    Borenäs, Karin
    et al.
    SMHI, Core Services.
    Lundberg, P
    The Faroe-Bank channel deep-water overflow2004In: Deep-sea research. Part II, Topical studies in oceanography, ISSN 0967-0645, E-ISSN 1879-0100, Vol. 51, no 4-5, p. 335-350Article in journal (Refereed)
    Abstract [en]

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

  • 207. 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.

  • 208. 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.

  • 209.
    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.

  • 210.
    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.

  • 211. 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)
  • 212. 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)
  • 213. 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.

  • 214. Bowling, Laura
    et al.
    Lettenmaier, Dennis
    Graham, Phil
    SMHI, Professional Services.
    Land-surface parameterizations in northern regions: preliminary results from the PILPS 2e model intercomparison.2001In: Third study conference on BALTEX / [ed] Jens Meywerk, 2001, p. 25-26Conference paper (Other academic)
  • 215. 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)
  • 216. 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)
  • 217.
    Brandt, Maja
    SMHI, Core Services.
    Areella snöstudier1986Report (Other academic)
    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.

  • 218.
    Brandt, Maja
    SMHI, Core Services.
    Bestämning av optimalt klimatstationsnät för hydrologiska prognoser1987Report (Other academic)
    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).

  • 219.
    Brandt, Maja
    SMHI, Core Services.
    GENERATION, TRANSPORT AND DEPOSITION OF SUSPENDED AND DISSOLVED MATERIAL - EXAMPLES FROM SWEDISH RIVERS1990In: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 72, no 3-4, p. 273-283Article in journal (Refereed)
    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.

  • 220.
    Brandt, Maja
    SMHI, Core Services.
    Human impacts and weather-dependent effects on water balance and water quality in some Swedish river basins1990Report (Other academic)
    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

  • 221.
    Brandt, Maja
    SMHI, Core Services.
    Sedimenttransport i svenska vattendrag exempel från 1967-19941996Report (Other academic)
    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.

  • 222.
    Brandt, Maja
    SMHI, Core Services.
    SIMULATION OF RUNOFF AND NITRATE TRANSPORT FROM MIXED BASINS IN SWEDEN1990In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 21, no 1, p. 13-34Article in journal (Refereed)
  • 223.
    Brandt, Maja
    SMHI, Core Services.
    Skogens inverkan på vattenbalansen1992Report (Other academic)
    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.

  • 224.
    Brandt, Maja
    SMHI, Core Services.
    Snömätning med georadar och snötaxeringar i övre Luleälven1991Report (Other academic)
    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.

  • 225.
    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.

  • 226.
    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)
  • 227.
    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.

  • 228.
    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)
  • 229.
    Brandt, Maja
    et al.
    SMHI, Core Services.
    Ehlert, Kurt
    SMHI, Core Services.
    Avrinningen från Sverige till omgivande hav1996Report (Other academic)
    Abstract [en]

    A data base of monthly runoff to seas around Sweden is created. This report presents long term, seasonal and spatial variations for the period 1930 - 1990. Runoff calculation are based on measurments, wich cover 86% of the land area and on estmate by proportioning against nearby reference station for the remaining 14%. The calculations are made for 265 land areas.

  • 230.
    Brandt, Maja
    et al.
    SMHI, Core Services.
    Grahn, Gun
    SMHI.
    Avdunstning och avrinningskoefficient i Sverige 1961-1990: Beräkningar med HBV-modellen1998Report (Other academic)
    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.

  • 231. 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.

  • 232. Brigode, Pierre
    et al.
    Brissette, Francois
    Nicault, Antoine
    Perreault, Luc
    Kuentz, Anna
    SMHI, Core Services.
    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 reanalysis2016In: Climate of the Past, ISSN 1814-9324, E-ISSN 1814-9332, Vol. 12, no 9, p. 1785-1804Article in journal (Refereed)
  • 233.
    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.

  • 234.
    Bringfelt, Björn
    SMHI.
    An evapotranspiration model using SYNOP weather observations in the Penman-Monteith equation1998Report (Other academic)
    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. 

  • 235.
    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)
  • 236.
    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)
  • 237.
    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.

  • 238.
    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)
  • 239. 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)
  • 240.
    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.

  • 241. 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)
  • 242. 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)
  • 243. 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

  • 244. 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)
  • 245. Bunse, Carina
    et al.
    Israelsson, Stina
    Baltar, Federico
    Bertos-Fortis, Mireia
    Fridolfsson, Emil
    Legrand, Catherine
    Lindehoff, Elin
    Lindh, Markus
    SMHI, Core Services.
    Martinez-Garcia, Sandra
    Pinhassi, Jarone
    High Frequency Multi-Year Variability in Baltic Sea Microbial Plankton Stocks and Activities2019In: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 9, article id 3296Article in journal (Refereed)
  • 246. 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.

  • 247. 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.

  • 248.
    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)
  • 249.
    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)
  • 250.
    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

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