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  • 2051.
    Vedin, Haldo
    et al.
    SMHI.
    Eriksson, Bertil
    SMHI.
    Extrem arealnederbörd i Sverige 1881-19881988Report (Other academic)
  • 2052. Veihelmann, B
    et al.
    Nousiainen, T
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    van der Zande, W J
    Light scattering by small feldspar particles simulated using the Gaussian random sphere geometry2006In: Journal of Quantitative Spectroscopy and Radiative Transfer, ISSN 0022-4073, E-ISSN 1879-1352, Vol. 100, no 1-3, p. 393-405Article in journal (Refereed)
    Abstract [en]

    The single-scattering properties of Gaussian random spheres are calculated using the discrete dipole approximation. The ensemble of model particles is assumed to be representative for a feldspar dust sample that is characteristic for weakly absorbing irregularly shaped mineral aerosol. The morphology of Gaussian random spheres is modeled based on a statistical shape analysis using microscope images of the dust sample. The size distribution of the dust sample is based on a particle sizing experiment. The refractive index of feldspar is estimated using literature values. All input parameters used in the light scattering simulations are thus obtained in an objective way based on the true properties of the mineral sample. The orientation-averaged and ensemble-averaged scattering matrices and cross sections of the Gaussian random spheres are compared with light scattering simulations using spheroidal shape models which have been shown to be applicable to the feldspar sample. The Gaussian random sphere model and the spheroidal shape model are assessed using the measured scattering matrix of the feldspar dust sample as a reference. Generally, the spheroidal model with strongly elongated prolate and strongly flattened oblate shapes agrees better with the measurement than the Gaussian random sphere model. In contrast, some features that are characteristic for light scattering by truly irregular mineral dust particles are rendered best by the Gaussian random sphere model; these features include the flat shape of the phase function and a minimum in the scattering matrix element F-22/F-11 as a function of the scattering angle. (c) 2005 Elsevier Ltd. All rights reserved.

  • 2053. Venohr, M
    et al.
    Donohue, I
    Fogelberg, S
    SMHI.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Irvine, K
    Behrendt, H
    Nitrogen retention in a river system and the effects of river morphology and lakes2005In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 51, no 3-4, p. 19-29Article in journal (Refereed)
    Abstract [en]

    The mean annual transfer (loss and retention) of nitrogen in a river system was estimated using a conceptual approach based on water surface area and runoff. Two different approaches for the calculation of water surface area were applied to determine riverine nitrogen retention in four European catchments, ranging between 860-14,000 km(2) in area, and differing considerably in the proportion and distribution of surface waters, specific runoff and specific nutrient emissions. The transfer rate was estimated sequentially as either the mean value for the total catchment, on a sub-catchment scale, or considering the distribution of water surface area within a sub-catchment. For the latter measure, nitrogen retention in larger lakes was calculated separately. Nitrogen emissions modelled with MONERIS and HBV-N were used to calculate nitrogen river loads and compare those with observed loads. Inclusion of the proportion of water area within a sub-catchment improved modelled results in catchment with large lakes in sub-catchments, but not where there was a homogenous distribution of surface waters among sub-catchments.

  • 2054.
    Venäläinen, Ari
    et al.
    Finnish Meteorological Institute, Finland.
    Saku, Seppo
    Finnish Meteorological Institute, Finland.
    Jylhä, Kirsti
    Finnish Meteorological Institute, Finland.
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Bärring, Lars
    SMHI, Research Department, Climate research - Rossby Centre.
    Climate extremes and safety of nuclear power plants: Extreme temperatures and enthalpy in Finland and Sweden in a changing climate.2009Report (Other academic)
  • 2055. Vercauteren, Nikki
    et al.
    Boyko, Vyacheslav
    Kaiser, Amandine
    Belusic, Danijel
    SMHI, Research Department, Climate research - Rossby Centre.
    Statistical Investigation of Flow Structures in Different Regimes of the Stable Boundary Layer2019In: Boundary-layer Meteorology, ISSN 0006-8314, E-ISSN 1573-1472, Vol. 173, no 2, p. 143-164Article in journal (Refereed)
    Abstract [en]

    A combination of methods originating from non-stationary time-series analysis is applied to two datasets of near-surface turbulence in order to gain insights on the non-stationary enhancement mechanism of intermittent turbulence in the stable atmospheric boundary layer (SBL). We identify regimes of SBL turbulence for which the range of time scales of turbulence and submeso motions, and hence their scale separation (or lack of separation), differs. Ubiquitous flow structures, or events, are extracted from the turbulence data in each flow regime. We relate flow regimes characterized by very stable stratification, but differing in the dynamical interactions and in the transport properties of different scales of motion, to a signature of flow structures thought to be submeso motions.

  • 2056. Verhoeven, J T A
    et al.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Yin, C Q
    Hefting, M M
    Regional and global concerns over wetlands and water quality2006In: Trends in Ecology & Evolution, ISSN 0169-5347, E-ISSN 1872-8383, Vol. 21, no 2, p. 96-103Article, review/survey (Refereed)
    Abstract [en]

    Water quality in many stream catchments and river basins is severely impacted by nutrient enrichment as a result of agriculture. Water-resource managers worldwide are considering the potential role of riparian zones and floodplain wetlands in improving stream-water quality, as there is evidence at the site scale that such wetlands are efficient at removing nutrients from through-flowing water. However, recent studies have highlighted disadvantages of such use of wetlands, including emissions of greenhouse gases and losses of biodiversity that result from prolonged nutrient loading. Here, we discuss the water purification function of wetlands at the site and catchment scale and suggest ways in which these disadvantages could be overcome.

  • 2057. Verma, Siddhartha
    et al.
    Bartosova, Alena
    SMHI, Research Department, Hydrology.
    Markus, Momcilo
    Cooke, Richard
    Um, Myoung-Jin
    Park, Daeryong
    Quantifying the Role of Large Floods in Riverine Nutrient Loadings Using Linear Regression and Analysis of Covariance2018In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 10, no 8, article id 2876Article in journal (Refereed)
  • 2058. Verma, Siddhartha
    et al.
    Markus, Momcilo
    Bartosova, Alena
    SMHI, Research Department, Hydrology.
    Cooke, Richard A.
    Intra-Annual Variability of Riverine Nutrient and Sediment Loadings Using Weighted Circular Statistics2018In: Journal of environmental engineering, ISSN 0733-9372, E-ISSN 1943-7870, Vol. 144, no 3, article id 04018010Article in journal (Refereed)
  • 2059. Vesakoski, Jenni-Mari
    et al.
    Nylen, Tua
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Gustafsson, David
    SMHI, Research Department, Hydrology.
    Isberg, Kristina
    SMHI, Research Department, Hydrology.
    Holopainen, Markus
    Hyyppa, Juha
    Alho, Petteri
    Arctic Mackenzie Delta channel planform evolution during 1983-2013 utilising Landsat data and hydrological time series2017In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 31, no 22, p. 3979-3995Article in journal (Refereed)
  • 2060. Vetter, Tobias
    et al.
    Reinhardt, Julia
    Floerke, Martina
    van Griensven, Ann
    Hattermann, Fred
    Huang, Shaochun
    Koch, Hagen
    Pechlivanidis, Ilias
    SMHI, Research Department, Hydrology.
    Ploetner, Stefan
    Seidou, Ousmane
    Su, Buda
    Vervoort, R. Willem
    Krysanova, Valentina
    Evaluation of sources of uncertainty in projected hydrological changes under climate change in 12 large-scale river basins2017In: Climatic Change, ISSN 0165-0009, E-ISSN 1573-1480, Vol. 141, no 3, p. 419-433Article in journal (Refereed)
  • 2061.
    Viktorsson, Lena
    et al.
    SMHI, Core Services.
    Wesslander, Karin
    SMHI, Core Services.
    Revidering av fysikaliska och kemiskabedömningsgrunder i kustvatten: Underlag inför uppdatering av HVMFS 2013:192018Report (Other academic)
    Abstract [sv]

    Detta är ett underlag för revidering av bilaga 5 i HVMFS 2013:19, Bedömningsgrunder för fysikaliskkemiskakvalitetsfaktorer i kustvatten och vatten i övergångszonen. Underlaget innefattar främst enuppdatering av referensvärden för näringsämnen samt förslag på uppdatering av viss text i föreskriftengällande syrebalans och siktdjup. Den generella metoden för var och en av stödparametrarna ibedömningsgrunderna bibehålls. I rapportens sista kapitel presenteras de uppdateringar av föreskriftenHVMFS 2013:19 som rekommenderas utifrån detta uppdrag.Efter en jämförelse av tidigare framtagna referensvärden för näringsämnen och de som tagits fram iden här rapporten rekommenderas att nya referensvärden i tillrinnande sötvatten används men atttidigare referensvärden för TN och TP vid utsjösalthalt samt att klassgränser behålls. En mindrejustering av referensvärden för DIN och DIP utifrån havsmiljöförordningens G/M värden föreslåsdock. De nya referensvärdena är framtagna med modellen S-HYPE (Lindström m.fl. 2010) förtillrinnande sötvatten och utifrån utsjövärden för oorganiskt fosfor och kväve (HVMFS 2012:18) samteffektsamband i mätdata. Det förtydligas också att ett konstant referensvärde för näringsämnenanvänds vid salthalter ≤2 psu.Den S-HYPE körning som använts för referensvärden i tillrinnande sötvatten är en bakgrundskörningsom är anpassad till definitionen av bakgrundsbelastning i PLC6 (Pollution Load Compilation 6,HELCOM).Utöver uppdatering av referensvärden för näringsämnen så föreslås en förändrad sammanvägning avkväve och fosfor i bedömningsgrunden. Det innebär att de ingående parametrarna för kväve och fosforsammanvägs var för sig. Bedömningsgrunderna ger då en separat status för varje näringsämne (kväveoch fosfor) baserat på de ingående parametrarna. Detta ger både en större möjlighet till att se vilketnäringsämne som bidrar till att eventuellt sänka status och stämmer överens med hur rapporteringentill EU-kommissionen ska ske.För syre rekommenderas en uppdatering om vilka mätmetoder som får användas, så att ävenmätningar med sensorer kan användas för statusbedömning. För siktdjup var ambitionen att ta fram etthumusgränsvärde för när kvalitetsfaktorn inte ska tillämpas. En fullständig statistisk analys har intehunnits med och en tydlig rekommendation kan inte ges.Det har under arbetet med att ta fram nya referensvärden för näringsämnen enligt nuvarande metodblivit tydligt att metoden för att bedöma näringsämnen behöver en mer övergripande uppdatering. Tillexempel kan metoden för salthaltskorrektion troligen förbättras med hjälp av en analys av mätdata ikombination med kustzonsmodellen.

  • 2062. Viney, Neil R.
    et al.
    Bormann, H.
    Breuer, L.
    Bronstert, A.
    Croke, B. F. W.
    Frede, H.
    Graeff, T.
    Hubrechts, L.
    Huisman, J. A.
    Jakeman, A. J.
    Kite, G. W.
    Lanini, J.
    Leavesley, G.
    Lettenmaier, D. P.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Seibert, J.
    Sivapalan, M.
    Willems, P.
    Assessing the impact of land use change on hydrology by ensemble modelling (LUCHEM) II: Ensemble combinations and predictions2009In: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 32, no 2, p. 147-158Article in journal (Refereed)
    Abstract [en]

    This paper reports on a project to compare predictions from a range of catchment models applied to a mesoscale river basin in central Germany and to assess various ensemble predictions of catchment streamflow. The models encompass a large range in inherent complexity and input requirements. In approximate order of decreasing complexity, they are DHSVM, MIKE-SHE, TOPLATS, WASIM-ETH, SWAT, PRMS, SLURP, HBV, LASCAM and IHACRES. The models are calibrated twice using different sets of input data. The two predictions from each model are then combined by simple averaging to produce a single-model ensemble. The 10 resulting single-model ensembles are combined in various ways to produce multi-model ensemble predictions. Both the single-model ensembles and the multi-model ensembles are shown to give predictions that are generally superior to those of their respective constituent models, both during a 7-year calibration period and a 9-year validation period. This occurs despite a considerable disparity in performance of the individual models. Even the weakest of models is shown to contribute useful information to the ensembles they are part of. The best model combination methods are a trimmed mean (constructed using the central four or six predictions each day) and a weighted mean ensemble (with weights calculated from calibration performance) that places relatively large weights on the better performing models. Conditional ensembles. in which separate model weights are used in different system states (e.g. summer and winter, high and low flows) generally yield little improvement over the weighted mean ensemble. However a conditional ensemble that discriminates between rising and receding flows shows moderate improvement. An analysis of ensemble predictions shows that the best ensembles are not necessarily those containing the best individual models. Conversely, it appears that some models that predict well individually do not necessarily combine well with other models in multi-model ensembles. The reasons behind these observations may relate to the effects of the weighting schemes, non-stationarity of the climate series and possible cross-correlations between models. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.

  • 2063. Vivanco, Marta G.
    et al.
    Theobald, Mark R.
    Garcia-Gomez, Hector
    Luis Garrido, Juan
    Prank, Marje
    Aas, Wenche
    Adani, Mario
    Alyuz, Ummugulsum
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Bellasio, Roberto
    Bessagnet, Bertrand
    Bianconi, Roberto
    Bieser, Johannes
    Brandt, Jurgen
    Briganti, Gino
    Cappelletti, Andrea
    Curci, Gabriele
    Christensen, Jesper H.
    Colette, Augustin
    Couvidat, Florian
    Cuvelier, Cornelis
    D'Isidoro, Massimo
    Flemming, Johannes
    Fraser, Andrea
    Geels, Camilla
    Hansen, Kaj M.
    Hogrefe, Christian
    Im, Ulas
    Jorba, Oriol
    Kitwiroon, Nutthida
    Manders, Astrid
    Mircea, Mihaela
    Otero, Noelia
    Pay, Maria-Teresa
    Pozzoli, Luca
    Solazzo, Efisio
    Tsyro, Svetlana
    Unal, Alper
    Wind, Peter
    Galmarini, Stefano
    Modeled deposition of nitrogen and sulfur in Europe estimated by 14 air quality model systems: evaluation, effects of changes in emissions and implications for habitat protection2018In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 18, no 14, p. 10199-10218Article in journal (Refereed)
  • 2064. Voisin, Nathalie
    et al.
    Hamlet, Alan F.
    Graham, Phil
    SMHI, Research Department, Climate research - Rossby Centre.
    Pierce, David W.
    Barnett, Tim P.
    Lettenmaier, Dennis P.
    The role of climate forecasts in Western US power planning2006In: Journal of Applied Meteorology and Climatology, ISSN 1558-8424, E-ISSN 1558-8432, Vol. 45, no 5, p. 653-673Article in journal (Refereed)
    Abstract [en]

    The benefits of potential electric power transfers between the Pacific Northwest (PNW) and California ( CA) are evaluated using a linked set of hydrologic, reservoir, and power demand simulation models for the Columbia River and the Sacramento-San Joaquin reservoir systems. The models provide a framework for evaluating climate-related variations and long-range predictability of regional electric power demand, hydropower production, and the benefits of potential electric power transfers between the PNW and CA. The period of analysis is 1917-2002. The study results show that hydropower production and regional electric power demands in the PNW and CA are out of phase seasonally but that hydropower productions in the PNW and CA have strongly covaried on an annual basis in recent decades. Winter electric power demand and spring and annual hydropower production in the PNW are related to both El Nino-Southern Oscillation (ENSO) and the Pacific decadal oscillation (PDO) through variations in winter climate. Summer power demand in CA is related primarily to variations in the PDO in spring. Hydropower production in CA, despite recent covariation with the PNW, is not strongly related to ENSO variability overall. Primarily because of strong variations in supply in the PNW, potential hydropower transfers between the PNW and CA in spring and summer are shown to be correlated to ENSO and PDO, and the conditional probability distributions of these transfers are therefore predictable with long lead times. Such electric power transfers are estimated to have potential average annual benefits of $136 and $79 million for CA and the PNW, respectively, at the year-2000 regional demand level. These benefits are on average 11%-27% larger during cold ENSO/PDO events and are 16%-30% lower during warm ENSO/PDO events. Power transfers from the PNW to CA and hydropower production in CA are comparable in magnitude, on average.

  • 2065. von Schuckmann, Karina
    et al.
    Le Traon, Pierre-Yves
    Alvarez-Fanjul, Enrique
    Axell, Lars
    SMHI, Research Department, Oceanography.
    Balmaseda, Magdalena
    Breivik, Lars-Anders
    Brewin, Robert J. W.
    Bricaud, Clement
    Drevillon, Marie
    Drillet, Yann
    Dubois, Clotilde
    Embury, Owen
    Etienne, Hélène
    Sotillo, Marcos García
    Garric, Gilles
    Gasparin, Florent
    Gutknecht, Elodie
    Guinehut, Stéphanie
    Hernandez, Fabrice
    Juza,, Melanie
    Karlson, Bengt
    SMHI, Research Department, Oceanography.
    Korres, Gerasimos
    Legeais, Jean-François
    Levier, Bruno
    Lien, Vidar S.
    Morrow, Rosemary
    Notarstefano, Giulio
    Parent, Laurent
    Pascual, Álvaro
    PérezGómez, Begoña
    Perruche, Coralie
    Pinardi, Nadia
    Pisano, Andrea
    Poulain, Pierre-Marie
    Pujol, Isabelle M.
    Raj, Roshin P.
    Raudsepp, Urmas
    Roquet, Hervé
    Samuelsen, Annette
    Sathyendranath, Shubha
    She, Jun
    Simoncelli, Simona
    Cosimo, Solidoro
    Tinker, Jonathan
    Tintoré, Joaquín
    Viktorsson, Lena
    SMHI, Core Services.
    Ablain, Michael
    Almroth-Rosell, Elin
    SMHI, Research Department, Oceanography.
    Bonaduce, Antonio
    Clementi, Emanuela
    Cossarini, Gianpiero
    Dagneaux, Quentin
    Desportes, Charles
    Dye, Stephen
    Fratianni, Claudia
    Good, Simon
    Greiner, Eric
    Gourrion, Jerome
    Hamon, Mathieu
    Holt, Jason
    Hyder, Pat
    Kennedy, John
    ManzanoMuñoz, Fernando
    Melet, Angélique
    Meyssignac, Benoit
    Mulet, Sandrine
    Buongiorno Nardelli, Bruno
    O´Dea, Enda
    Olason, Einar
    Paulmier, Aurélien
    Pérez-González, Irene
    Reid, Rebecca
    Racault, Marie-Fanny
    Raitsos, Dionysios E.
    Ramos,, Antonio
    Sykes, Peter
    Szekely, Tanguy
    Verbrugge, Nathalie
    The Copernicus Marine Environment Monitoring Service Ocean State Report2017In: Journal of operational oceanography. Publisher: The Institute of Marine Engineering, Science & Technology, ISSN 1755-876X, E-ISSN 1755-8778, Vol. 9, no Sup.2, p. 235-320Article in journal (Refereed)
  • 2066. Vuorinen, Ilppo
    et al.
    Hanninen, Jari
    Rajasilta, Marjut
    Laine, Paivi
    Eklund, Jan
    Montesino-Pouzols, Federico
    Corona, Francesco
    Junker, Karin
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Dippner, Joachim W.
    Scenario simulations of future salinity and ecological consequences in the Baltic Sea and adjacent North Sea areas - Implications for environmental monitoring (vol 50, pg 196, 2015)2015In: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 53, p. 294-294Article in journal (Refereed)
  • 2067. Vuorinen, Ilppo
    et al.
    Hanninen, Jari
    Rajasilta, Marjut
    Laine, Paivi
    Eklund, Jan
    Montesino-Pouzols, Federico
    Corona, Francesco
    Junker, Karin
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Dippner, Joachim W.
    Scenario simulations of future salinity and ecological consequences in the Baltic Sea and adjacent North Sea areas-implications for environmental monitoring2015In: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 50, p. 196-205Article in journal (Refereed)
    Abstract [en]

    Substantial ecological changes occurred in the 1970s in the Northern Baltic during a temporary period of low salinity (S). This period was preceded by an episodic increase in the rainfall over the Baltic Sea Watershed area. Several climate models, both global and regional, project an increase in the runoff of the Northern latitudes due to proceeding climate change. The aim of this study is to model, firstly, the effects on Baltic Sea salinity of increased runoff due to projected global change and, secondly, the effects of salinity change on the distribution of marine species. The results suggest a critical shift in the S range 5-7, which is a threshold for both freshwater and marine species distributions and diversity. We discuss several topics emphasizing future monitoring, modelling, and fisheries research. Environmental monitoring and modelling are investigated because the developing alternative ecosystems do not necessarily show the same relations to environment quality factors as the retiring ones. An important corollary is that the observed and modelled S changes considered together with species' ranges indicate what may appear under a future climate. Consequences could include a shift in distribution areas of marine benthic foundation species and some 40-50 other species, affiliated to these. This change would extend over hundreds of kilometres, in the Baltic Sea and the adjacent North Sea areas. Potential cascading effects, in coastal ecology, fish ecology and fisheries would be extensive, and point out the necessity to develop further the "ecosystem approach in the environmental monitoring". (C) 2014 The Authors. Published by Elsevier Ltd.

  • 2068.
    Väli, Germo
    et al.
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Elken, Jüri
    Marine Systems Institute at Tallinn University of Technology, Tallinn, Estonia.
    Simulated variations of the Baltic Sea halocline during 1961-20072012Report (Other academic)
    Abstract [en]

    The variations in the Baltic Sea salinity and the mean halocline depth during 1961-2007 are studied using Rossby Centre Ocean model. The largest trend in the monthly mean salinity averaged over the top 15 m was found in the Gulf of Riga and Baltic proper, while the trend in the northernmost part was non-existant. A period with shallow halocline in the Baltic Sea during 1970-1975 was identified and a period with deep halocline during 1990-1995 with the difference exceeding morethan 15 m in the Baltic proper between the two time-periods. Model simulation indicated that the mean surface salinity in the Baltic Sea is spatially controlled by the accumulated river runoff, while the mean salinity below the halocline in the Baltic proper by the mean zonal and absolute wind speed. The halocline depth in the Baltic Sea is affected significantly by the freshwater content and absolute wind speed. The impact of the mean zonal wind speed to the mean halocline depth in the Baltic proper is moderate, while the impact of runoff is low.

  • 2069. Walther, Alexander
    et al.
    Jeong, Jee-Hoon
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Jones, Colin
    SMHI, Research Department, Climate research - Rossby Centre.
    Chen, Deliang
    Evaluation of the warm season diurnal cycle of precipitation over Sweden simulated by the Rossby Centre regional climate model RCA32013In: Atmospheric research, ISSN 0169-8095, E-ISSN 1873-2895, Vol. 119, p. 131-139Article in journal (Refereed)
    Abstract [en]

    This study examines the diurnal cycle of precipitation over Sweden for the warm season (April to September) both in hourly observational data and in simulations from the Rossby Centre regional climate model (RCA3). A series of parallel long-term simulations of RCA3 with different horizontal resolutions - 50, 25, 12, and 6 km - were analyzed to investigate the sensitivity of the model's horizontal resolution to the simulated diurnal cycle of precipitation. Overall, a clear distinction between an afternoon peak for inland stations and an early morning peak for stations along the Eastern coast is commonly found both in observation and model results. However, the diurnal cycle estimated from the model simulations show too early afternoon peaks with too large amplitude compared to the observation. Increasing horizontal model resolution tends to reduce this bias both in peak timing and amplitude, but this resolution effect seems not to be monotonic; this is clearly seen only when comparing coarser resolution results with the 6 km resolution result. As the resolution increases, the peak timing and amplitude of the diurnal cycle of resolved large-scale precipitation become more similar to the observed cycle of total precipitation while the contribution of subgrid scale convective precipitation to the total precipitation decreases. An increase in resolution also tends to reduce too much precipitation of relatively light intensity over inland compared to the observation, which may also contribute to the more realistic simulation of the afternoon peak in convective precipitation. (C) 2011 Elsevier B.V. All rights reserved.

  • 2070. Walve, J
    et al.
    Höglander, H
    Andersson, A
    Karlson, Bengt
    SMHI, Research Department, Oceanography.
    Karlsson, C
    Johansen, Marie
    SMHI, Core Services.
    Phytoplankton in coastal waters2016In: Ecological Assessment of Swedish Water Bodies; development, harmonisation and integration of biological indicators.: Final report of the research programme WATERS. Deliverable 1.1-4, WATERS report no 2016:10. Havsmiljöinstitutet, Sweden, 95-106., 2016Chapter in book (Other academic)
  • 2071. Wang, Jia
    et al.
    Kwok, Ron
    Saucier, F. J.
    Hutchings, J
    Ikeda, M
    Hibler III, W
    Haapala, J
    Coon, M.D.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Eicken, H
    Tanaka, N
    Prentki, D
    Johnsson, W
    Working toward improved small‐scale sea ice‐ocean modeling in the Arctic seas2003In: EOS: Transactions, ISSN 0096-3941, E-ISSN 2324-9250, Vol. 84, no 34, p. 325-330Article in journal (Refereed)
  • 2072.
    Wang, Shiyu
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Dieterich, Christian
    SMHI, Research Department, Oceanography.
    Doescher, Ralf
    SMHI, Research Department, Climate research - Rossby Centre.
    Höglund, Anders
    SMHI, Research Department, Oceanography.
    Hordoir, Robinson
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Samuelsson, Patrick
    SMHI, Research Department, Climate research - Rossby Centre.
    Schimanke, Semjon
    SMHI, Research Department, Oceanography.
    Development and evaluation of a new regional coupled atmosphere-ocean model in the North Sea and Baltic Sea2015In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 67, article id 24284Article in journal (Refereed)
    Abstract [en]

    A new regional coupled model system for the North Sea and the Baltic Sea is developed, which is composed of the regional setup of ocean model NEMO, the Rossby Centre regional climate model RCA4, the sea ice model LIM3 and the river routing model CaMa-Flood. The performance of this coupled model system is assessed using a simulation forced with ERA-Interim reanalysis data at the lateral boundaries during the period 1979-2010. Compared to observations, this coupled model system can realistically simulate the present climate. Since the active coupling area covers the North Sea and Baltic Sea only, the impact of the ocean on the atmosphere over Europe is small. However, we found some local, statistically significant impacts on surface parameters like 2m air temperature and sea surface temperature (SST). A precipitation-SST correlation analysis indicates that both coupled and uncoupled models can reproduce the air-sea relationship reasonably well. However, the coupled simulation gives slightly better correlations even when all seasons are taken into account. The seasonal correlation analysis shows that the air-sea interaction has a strong seasonal dependence. Strongest discrepancies between the coupled and the uncoupled simulations occur during summer. Due to lack of air-sea interaction, in the Baltic Sea in the uncoupled atmosphere-standalone run the correlation between precipitation and SST is too small compared to observations, whereas the coupled run is more realistic. Further, the correlation analysis between heat flux components and SST tendency suggests that the coupled model has a stronger correlation. Our analyses show that this coupled model system is stable and suitable for different climate change studies.

  • 2073. Wang, Zhan
    et al.
    Belusic, Danijel
    SMHI, Research Department, Climate research - Rossby Centre.
    Huang, Yi
    Siems, Steven T.
    Manton, Michael J.
    Understanding Orographic Effects on Surface Observations at Macquarie Island2016In: Journal of Applied Meteorology and Climatology, ISSN 1558-8424, E-ISSN 1558-8432, Vol. 55, no 11, p. 2377-2395Article in journal (Refereed)
  • 2074. Wang, Zifa
    et al.
    Xie, Fuying
    Sakurai, T.
    Ueda, H.
    Han, Zhiwei
    Carmichael, G. R.
    Streets, D.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Holloway, T.
    Hayami, H.
    Kajino, M.
    Thongboonchoo, N.
    Bennet, Cecilia
    SMHI, Research Department, Air quality.
    Park, S. U.
    Fung, C.
    Chang, A.
    Sartelet, K.
    Amann, M.
    MICS-Asia II: Model inter-comparison and evaluation of acid deposition2008In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 42, no 15, p. 3528-3542Article in journal (Refereed)
    Abstract [en]

    This paper focuses on the comparison of chemical deposition of eight regional chemical models used in Model Inter-Comparison Study for Asia (MICS-Asia) II. Monthly-mean depositions of chemical species simulated by these models, including dry deposition of SO(2), HNO(3), NH(3), Sulfate, nitrate and ammonium and wet deposition of SO(4)(2-), NO(3)(-) and NH(4)(+), have been provided for four periods (March, July, December 2001 and March 2002) in this work. Observations at 37 sites of the Acid Deposition Monitoring Network in East Asia (EANET) are compared with SO(4)(2-), NO(3)(-) and NH(4)(+) wet deposition model results. Significant correlations appeared between the observation and computed ensemble mean of participant models. Also, differences among modeled sulfur and nitrogen dry depositions have been studied at the EANET sites. Based on the analysis of acid deposition for various species from different models, total depositions of sulfur (SO(2) and sulfate) and nitrogen (nitrate and ammonium) have been evaluated as the ensemble mean of the eight models. In general, all models capture the observed spatial distribution' of sulfur and nitrogen deposition, although the absolute values may differ from measurements. High deposition often occurs in eastern China, Japan, the Republic of Korea, Thailand, Vietnam, Philippines and other parts of Southeast Asia. The magnitude of model bias is quite large for many of the models. In examining the reasons for model-measurement disagreement, we find that differences in chemical processes, deposition parameterization, and modeled precipitation are the main reasons for large model disparities. (C) 2008 Elsevier Ltd. All rights reserved.

  • 2075. Watson, Laura
    et al.
    Lacressonniere, Gwendoline
    Gauss, Michael
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Josse, Beatrice
    Marecal, Virginie
    Nyiri, Agnes
    Sobolowski, Stefan
    Siour, Guillaume
    Szopa, Sophie
    Vautard, Robert
    Impact of emissions and+2 degrees C climate change upon future ozone and nitrogen dioxide over Europe2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 142, p. 271-285Article in journal (Refereed)
  • 2076. Watson, Laura
    et al.
    Lacressonniere, Gwendoline
    Gauss, Michael
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Josse, Beatrice
    Marecal, Virginie
    Nyiri, Agnes
    Sobolowski, Stefan
    Siour, Guillaume
    Vautard, Robert
    The impact of meteorological forcings on gas phase air pollutants over Europe2015In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 119, p. 240-257Article in journal (Refereed)
    Abstract [en]

    The impact of meteorological forcings on gas phase air pollutants (ozone and nitrogen dioxide) over Europe was studied using four offline chemistry transport models (CTMs) as part of the IMPACT2C project. This study uses long (20- and 30-year) simulations to evaluate the present-day performance of the CTMs, which is a necessary first step before undertaking any analysis of future air quality impacts. Two sets of meteorological forcings were used for each model: reanalysis of past observation data (ERA-Interim) and Global Climate Model (GCM) output. The results for the simulations forced by reanalysis data were assessed in relation to AirBase v7 measurement data, and it was determined that all four models slightly overpredict annual O-3 values (mean biases range between 0.7 and 6.6 ppb) and three out of the four models underpredict observed annual NO2 (mean biases range between -3.1 and -5.2 ppb). The simulations forced by climate models result in spatially averaged monthly concentrations of O-3 that are generally between 0 and 5 ppb higher than the values obtained from simulations forced by reanalysis data; therefore it was concluded that the use of climate models introduces an additional bias to the results, but this bias tends not to be significant in the majority of cases. The bias in O-3 results appears to be correlated mainly to differences in temperature and boundary layer height between the two types of simulations, whereas the less significant bias in NO2 is negatively correlated to temperature and boundary layer height. It is also clear that the selection of chemical boundary conditions is an important factor in determining the variability of O-3 model results. These results will be used as a baseline for the interpretation of future work, which will include an analysis of future climate scenarios upon European air quality. (C) 2015 Elsevier Ltd. All rights reserved.

  • 2077. Weichselgartner, Juergen
    et al.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Evolving Climate Services into Knowledge-Action Systems2019In: Weather, Climate, and Society, ISSN 1948-8327, E-ISSN 1948-8335, Vol. 11, no 2, p. 385-399Article in journal (Refereed)
  • 2078. Weigel, Benjamin
    et al.
    Andersson, Helén
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Blenckner, Thorsten
    Snickars, Martin
    Bonsdorff, Erik
    Long-term progression and drivers of coastal zoobenthos in a changing system2015In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 528, p. 141-159Article in journal (Refereed)
    Abstract [en]

    Coastal zones are facing climate-driven change coupled with escalating eutrophication. With increasing shifts in hydrographic conditions during the past few decades, a focal task is to understand how environmental drivers affect zoobenthic communities, which play a crucial role in ecosystem functioning. By using long-term data, spanning 40 yr (1973 to 2013) in the northern Baltic Sea, we showed a disparity in zoobenthic responses with pronounced changes in community composition and a trend towards decreased biomass in sheltered areas, while biomasses increased in exposed areas of the coastal zone. We used generalized additive modeling to show that bottom oxygen saturation, sea surface temperature and organic load of the sediments were the main environmental drivers behind contrasting patterns in biomass progression. Oxygen saturation alone explained over one third of the deviation in the biomass developments in sheltered areas, while exposed areas were mainly limited by organic content of the sediments. We analyzed high-resolution climate-scenario simulations, following the Intergovernmental Panel on Climate Change scenarios for the Baltic Sea region in combination with different nutrient load scenarios, for the end of the 21st century. The scenario outcomes showed negative trends in bottom oxygen concentrations throughout the coastal and archipelago zone along with overall increasing temperatures and primary production, and decreasing salinity. Our results suggest that these projected future conditions will strengthen the observed pattern in decreasing zoobenthic production in the immediate coastal zones. Moreover, the potential intensification of unfavorable conditions ex-panding seaward may lead to an expansion of biomass loss to more exposed sites.

  • 2079. Wells, Mark L.
    et al.
    Trainer, Vera L.
    Smayda, Theodore J.
    Karlson, Bengt
    SMHI, Research Department, Oceanography.
    Trick, Charles G.
    Kudela, Raphael M.
    Ishikawa, Akira
    Bernard, Stewart
    Wulff, Angela
    Anderson, Donald M.
    Cochlan, William P.
    Harmful algal blooms and climate change: Learning from the past and present to forecast the future2015In: Harmful Algae, ISSN 1568-9883, E-ISSN 1878-1470, Vol. 49, p. 68-93Article in journal (Refereed)
    Abstract [en]

    Climate change pressures will influence marine planktonic systems globally, and it is conceivable that harmful algal blooms may increase in frequency and severity. These pressures will be manifest as alterations in temperature, stratification, light, ocean acidification, precipitation-induced nutrient inputs, and grazing, but absence of fundamental knowledge of the mechanisms driving harmful algal blooms frustrates most hope of forecasting their future prevalence. Summarized here is the consensus of a recent workshop held to address what currently is known and not known about the environmental conditions that favor initiation and maintenance of harmful algal blooms. There is expectation that harmful algal bloom (HAB) geographical domains should expand in some cases, as will seasonal windows of opportunity for harmful algal blooms at higher latitudes. Nonetheless there is only basic information to speculate upon which regions or habitats HAB species may be the most resilient or susceptible. Moreover, current research strategies are not well suited to inform these fundamental linkages. There is a critical absence of tenable hypotheses for how climate pressures mechanistically affect HAB species, and the lack of uniform experimental protocols limits the quantitative cross-investigation comparisons essential to advancement. A HAB "best practices" manual would help foster more uniform research strategies and protocols, and selection of a small target list of model HAB species or isolates for study would greatly promote the accumulation of knowledge. Despite the need to focus on keystone species, more studies need to address strain variability within species, their responses under multifactorial conditions, and the retrospective analyses of long-term plankton and cyst core data; research topics that are departures from the norm. Examples of some fundamental unknowns include how larger and more frequent extreme weather events may break down natural biogeographic barriers, how stratification may enhance or diminish HAB events, how trace nutrients (metals, vitamins) influence cell toxicity, and how grazing pressures may leverage, or mitigate HAB development. There is an absence of high quality time-series data in most regions currently experiencing HAB outbreaks, and little if any data from regions expected to develop HAB events in the future. A subset of observer sites is recommended to help develop stronger linkages among global, national, and regional climate change and HAB observation programs, providing fundamental datasets for investigating global changes in the prevalence of harmful algal blooms. Forecasting changes in HAB patterns over the next few decades will depend critically upon considering harmful algal blooms within the competitive context of plankton communities, and linking these insights to ecosystem, oceanographic and climate models. From a broader perspective, the nexus of HAB science and the social sciences of harmful algal blooms is inadequate and prevents quantitative assessment of impacts of future HAB changes on human wellbeing. These and other fundamental changes in HAB research will be necessary if HAB science is to obtain compelling evidence that climate change has caused alterations in HAB distributions, prevalence or character, and to develop the theoretical, experimental, and empirical evidence explaining the mechanisms underpinning these ecological shifts. (C) 2015 Elsevier B.V. All rights reserved.

  • 2080. Wells, M.L
    et al.
    Karlson, Bengt
    SMHI, Research Department, Oceanography.
    Harmful Algal Blooms in a Changing Ocean2018In: Global Ecology and Oceanography of Harmful Algal Blooms, Ecological Studies, vol. 232: Presents the key research areas of the international GEOHAB programme / [ed] Glibert, P.M., Berdalet, E., Burford, M.A., Pitcher, G.C., Zhou, M. (Eds.), Springer International Publishing , 2018, 1, p. 77-90Chapter in book (Other academic)
  • 2081.
    Wern, Lennart
    SMHI, Core Services.
    Avesta stadsmodell1985Report (Other academic)
  • 2082.
    Wern, Lennart
    SMHI, Core Services.
    Extrem nederbörd i Sverige under 1 till 30 dygn, 1900 - 20112012Report (Other academic)
    Abstract [en]

    This study shows that, in general, extreme precipitation has increased from 1900 until the 1930s and then reduced until the 1970s, before increasing until the present day. There is more extreme precipitation now than in the 1930s. In particular an accumulation of extreme precipitation in Götaland (the southern part of Sweden) has been seen during the 2000s. It has been noted that the greatest precipitation in Sweden usually occurs in July or August but there are some exceptions for different parts of the country and different seasons. We need to be careful about extrapolating the last 40 years increase into the future in the belief that the increase will continue. This report says nothing about the future, and those interested in extreme precipitation in a future climate should study the results of climate models that calculate future scenarios. Areas affected by the worst downpours during one day are mainly the southern coast of Norrland, Svealand, eastern Götaland and Skåne. Western Götaland, in particular central Halland, is often affected by large precipitation volumes but does not usually receive the highest amounts. The mountains have also had extreme rainfall but usually during a longer period of time – from a week up to 30 days. This report describes extreme precipitation lasting from 1 to 30 days during 112 years, between 1900 and 2011. Only digital data has been used to compile the information in this report. A large proportion of precipitation data before 1961 is unfortunately only available in paper format and could not be used in this study. Prior to 1961, there were only about 60 digital stations, but since 1961 there have been about 700 operational stations. A digitalisation project is being carried out at SMHI to transfer data from paper logs to digital form so that it can be processed by computer programs. This is a large project that will take many years to complete. Sixty stations with a time series of at least 100 years between 1900 and 2011 have been selected to describe how extreme precipitation has varied over 112 years. These stations are fairly evenly distributed throughout the country. Calculating recurrence times required stations with at least 25 years of data during the period 1961 – 2011, which means that over 670 stations have been used. All precipitation measurements are associated with errors due to for example aerodynamic problems and evaporation, which often leads to an underestimation of the precipitation volume. This study has focused on extreme precipitation which often falls in the form of large rain drops. The underestimation is assumed to be less than an average of 5 – 10 %. There has been a gradual improvement in the quality of the precipitation measurements due to the introduction of wind shields around the rain gauges up until 1935 and a switch from zinc containers to seamless aluminium containers (without the risk of leakage) up until the start of the 1960s. After that, precipitation has been measured in the same way until 1996 when around 100 of the 750 stations were changed to a new type of automatic gauge with a different type of wind shield. This report makes no attempt at homogenising the data, and uses the observed values directly. There is however a discussion on different error sources. Variations in extreme precipitation during the 112-year period of study have been described in this report for Sweden as a whole but also for different seasons and for different parts of the country: Northern Norrland, southern Norrland, Svealand and Götaland. The most extreme cases have been analysed using maps with a short descriptive text. Recurrence times of precipitation volumes with different durations are calculated and presented on a map.

  • 2083.
    Wern, Lennart
    SMHI, Core Services.
    Extrema byvindar i Orrefors1986Report (Other academic)
  • 2084.
    Wern, Lennart
    SMHI, Core Services.
    Luftfuktighet: Variationer i Sverige2014Report (Other academic)
    Abstract [en]

    This report gives a general description of water vapour which is a transparent and odourless gas, how this gas varies geographically outdoors in Sweden as well as the diurnal and annual variation. Humidity data from 121 automatic weather stations that were operational during the period 1996-2012 was used. The measurements were taken at 1.5 to 2 meters above the ground level. Different measuring instruments for humidity are presented and also different humidity measurements like dew point, wet bulb, absolute humidity, mixing ratio, enthalpy etc. The absolute humidity which is the mass of water vapour in a cubic meter of air is highest in summer and lowest during the coldest days in winter. The highest values are measured along the coasts of southern Sweden and the value decreases northwards and with distance from the coast. Diurnal variation of the absolute humidity is in average relatively small. In addition, monthly mean water vapour is studied for various months since 1951. Digitized humidity data have not been available before in 1951. Ten stations are used, from Bredåkra in the south of Sweden to Arjeplog in the north, for calculating monthly averages. The months May, August and November have been chosen together with the annual value. The absolute humidity increased during the three months and also the annual value. For the annual value and for May and August the increase is statistically significant not for November. There is no statistically significant change of the average relative humidity during the period 1951-2012 for the average of ten selected stations for the months of May, August or November. If the temperature drops to the dew point the air becomes saturated with water vapour and the relative humidity becomes 100 %. If the temperature drops further the water vapour condensates to water droplets and fog, dew or frost is formed. The highest dew point reported in Sweden is 23.8 °C at Fårö north of the island Gotland on 29 July 1994 and in Hällum in Västergötland on 30 June 1997. At the latter occasion the temperature was 28.4 °C and the relative humidity 76%. The relative humidity is usually given in percentage (%) that is a measure of how much water vapour the air contains compared to how much water vapour that the air can contain as a maximum at the ambient temperature. The amount of water vapour that can occur as gas form increases with temperature. Low relative humidity is common during spring and early summer, while high relative humidity occurs during nights and during winter. In May, when the sea water is cool, the relative humidity is higher along the Swedish coast compared to inland. In November, when the sea water is warmer than the land, there is a reverse relationship; the relative humidity is lower on the coast compared to inland. In Helsingborg, the relative humidity is in average 50-60% when the temperature is +25 °C, but when the temperature is between 0 and +10 °C the humidity is much higher, 90 to 100 %.

  • 2085.
    Wern, Lennart
    SMHI, Core Services.
    Snödjup i Sverige 1904/05 – 2013/142015Report (Other academic)
    Abstract [sv]

    Rapporten ger en beskrivning av snöförhållandena i Sverige under vintrarna 1904/05 till 2013/14. Speciellt har vinterns största snödjup, antal dagar med snötäcke och stora snödjupsökningar under ett dygn studerats. Snödjupsrekord för olika månader och landsdelar har sammanställts. Svåra snövintrar beskrivs liksom olika exempel på extrema snöfall och snödjup med återkomsttiden 10 och 50 år. Vid en jämförelse av vintrarna under perioderna 1991 – 2014 med 1961 – 1990 så har vinterns största snödjup och antal dagar med snötäcke minskat i nästan hela landet. Stora snödjupsökningar från en dag till nästa beror ofta på så kallade snökanoner som oftast bildas över Östersjön vid vind från öster. Speciellt utsatt för snökanoner är Norrlandskusten från Skellefteå ner till Gävle men även Smålandskusten, Vänern och Vättern är drabbat. Den vinter som varit snörikast är 1965/66 om man ser till vinterns största snödjup i Sverige som helhet. I olika delar av Sverige har det under andra vintrar förekommit större snödjup än under 1965/66. Exempelvis var det extremt mycket snö i fjällen 1988/89 och vintern 2009/10 var den snörikaste vintern i Götaland under hela den studerade perioden.

  • 2086.
    Wern, Lennart
    SMHI, Core Services.
    Spridningsberäkningar för ASEA transformers i Ludvika1985Report (Other academic)
  • 2087.
    Wern, Lennart
    SMHI, Core Services.
    Spridningsberäkningar för ett kraftvärmeverk i Sundbyberg1986Report (Other academic)
  • 2088.
    Wern, Lennart
    SMHI, Core Services.
    Spridningsberäkningar för lösningsmedel i Tibro1986Report (Other academic)
  • 2089.
    Wern, Lennart
    SMHI, Core Services.
    Spridningsberäkningar för svavelsyrafabrik i Falun1986Report (Other academic)
  • 2090.
    Wern, Lennart
    SMHI, Core Services.
    Spridningsberäkningar för Volvo BM ABs anläggning i Braås1986Report (Other academic)
  • 2091.
    Wern, Lennart
    SMHI, Core Services.
    Spridningsberäkningar för Volvo Hallsbergverken1986Report (Other academic)
  • 2092.
    Wern, Lennart
    et al.
    SMHI, Core Services.
    Bärring, Lars
    SMHI, Research Department, Climate research - Rossby Centre.
    Sveriges vindklimat 1901-2008: Analys av trend i geostrofisk vind2009Report (Other academic)
    Abstract [sv]

    En studie har gjorts hur vinden har varierat i Sverige under perioden 1901 - 2008. Eftersom det saknas långa homogena mätserier av vindhastighet i Sverige har vi utgått från tryckmätningar och beräknatden s.k. geostrofiska vinden i elva trianglar som täcker Sverige. Eftersom bara tre observationer per dag (morgon, middag och kväll) har funnits att tillgå så kan det ha blåst mer mellan observationerna.Ett stort arbete har lagts ner på att kontrollera och rätta felaktiga observationer. Mellan åren 1951 och 2008 har varje observerat värde jämförts med ett interpolerat värde. Om skillnaden varit mer än 4 - 5 hPa har en karta analyserats för att kunna avgöra om det i databasen lagrade värdet varit korrekt. Kanske tusen tryckkartor har analyserats. Även två närliggande stationers observationer har jämförts till exempel Bromma och Observatoriekullen. Före 1951 har granskningsarbetet varit begränsat eftersom digitaliserade data saknas för fler stationer än de som ingår i denna undersökning.Förändringen av vindklimatet i elva trianglar som täcker huvuddelen av Sverige har studerats medhjälp av flera olika mått, bland annat:- Årets högsta vindhastighet- Årets medelvindhastighet- Antal fall på minst 25 m/s under året- Potentiell vindenergi under åretÅrets högsta geostrofiska vindhastighet har även jämförts med högsta havsvattenstånd och skogsskador.I det studerade materialet inträffade den absolut högsta geostrofiska vindhastigheten den 13 januari 1984 i den sydligaste triangeln Göteborg - Visby - Lund. Då beräknades den geostrofiska vindhastigheten till 66 m/s och vindriktningen var 235°.Denna undersökning visar bland annat att:- Årets högsta vindhastighet har ökat i fem trianglar och minskat i sex trianglar sedan 1951. Den sammanvägde trenden i Sverige visar på en svag ökning som inte är statistiskt signifikant.- Antal tillfällen per år då vindhastigheten varit minst 25 m/s har minskat i sju av de elva trianglarna sedan 1951.- Medelvindhastigheten har minskat i tio av de elva trianglarna sedan 1951. För fyra trianglar i norra Sverige är denna minskning statistiskt signifikant. Sammantaget för Sverige har medelvindhastigheten minskat med 4 %.- På samma sätt har den potentiella vindenergin minskat i dessa tio trianglar sedan 1951-talet. Minskningen är statistiskt signifikant i de fyra nordliga trianglarna. Sammantaget för Sverige har energin minskat med 7 %.

  • 2093.
    Wern, Lennart
    et al.
    SMHI, Core Services.
    Fredriksson, Ulf
    SMHI, Core Services.
    Spridningsberäkning för Kockums Plåt-teknik, Ronneby1986Report (Other academic)
  • 2094.
    Wern, Lennart
    et al.
    SMHI, Core Services.
    Fredriksson, Ulf
    SMHI, Core Services.
    Ring, Sture
    SMHI, Professional Services.
    Spridningsberäkningar för lösningsmedel i Tidaholm1986Report (Other academic)
  • 2095.
    Wern, Lennart
    et al.
    SMHI, Core Services.
    German, Jonas
    SMHI.
    Korttidsnederbörd i Sverige 1995 - 20082009Report (Other academic)
    Abstract [sv]

    Korta men intensiva regnhändelser är mycket viktiga inom bland annat urban hydrologi då vi här har att göra med snabba förlopp där avrinningen sker från små ytor som till stor del är hårdgjorda. Nederbördsserier med hög upplösning har därför mycket stor betydelse för all planering, analys och dimensionering av dagvattensystem, oavsett om det är frågan om rörnät eller öppna diken. Regn med varaktighet 15 min till 96 timmar har studerats genom att analysera nederbördsdata från SMHIs nät av automatiska väderstationer.Dessa stationer började installeras under våren 1995 och från början av 1996 var de flesta stationer igång. Den period vi har studerat är maj 1995 till september 2008. 114 automatstationerna har registrerat nederbörd under någon del av denna period. Sammanlagt finns 1211 stationsår med 15 minuters nederbörd. Data har granskats och ett mindre antal orimliga observationer har tagits bort eller rättats. Sammanställningar av årets största regn med olika varaktigheter har gjorts. Nederbördsmängder med olika varaktighet från 15 min till 96 timmar för olika återkomsttider har beräknats med extremvärdesanalys.Den studerade perioden är för kort och antalet stationer är för få för att bestämma regionala skillnader i Sverige av korttidsnederbörd. Därför har medelvärden av korttidsnederbörd för hela Sverige beräknats. Resultat har jämförts med tidigare studier av Dahlström (2006) och Hernebring (2006). Överensstämmelsen är god för kortare regn och kortare återkomsttider.

  • 2096.
    Wern, Lennart
    et al.
    SMHI, Core Services.
    Kindell, Sven
    SMHI, Professional Services.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Luktberäkningar för AB ELMO i Flen1986Report (Other academic)
  • 2097.
    Wern, Lennart
    et al.
    SMHI, Core Services.
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    Spridningsberäkningar för Volvos planerade bilfabrik i Uddevalla - energicentralen1985Report (Other academic)
  • 2098.
    Wern, Lennart
    et al.
    SMHI, Core Services.
    Ring, Sture
    SMHI, Professional Services.
    Spridningsberäkningar för ny ugn, SSAB II1986Report (Other academic)
  • 2099.
    Wern, Lennart
    et al.
    SMHI, Core Services.
    Ring, Sture
    SMHI, Professional Services.
    Spridningsberäkningar för Västhamns-verket HKV1 i Helsingborg1986Report (Other academic)
  • 2100.
    Wern, Lennart
    et al.
    SMHI, Core Services.
    Ring, Sture
    SMHI, Professional Services.
    Spridningsberäkningar, SSAB1986Report (Other academic)
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