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  • 1. Bal, S.
    et al.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Spangehl, T.
    Cubasch, U.
    On the robustness of the solar cycle signal in the Pacific region2011Inngår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 38, artikkel-id L14809Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The potential role of the stratosphere for the 11-year solar cycle signal in the Pacific region is investigated by idealized simulations using a coupled atmosphere-ocean general circulation model. The model includes a detailed representation of the stratosphere and accounts for changes in stratospheric heating rates from prescribed time dependent variations of ozone and spectrally high resolved solar irradiance. Three transient simulations are performed spanning 21 solar cycles each. The simulations use slightly different ozone perturbations representing uncertainties of solar induced ozone variations. The model reproduces the main features of the 20th century observed solar response. A persistent mean sea level pressure response to solar forcing is found for the eastern North Pacific extending over North America. Moreover, there is evidence for a La Nina-like response assigned to solar maximum conditions with below normal SSTs in the equatorial eastern Pacific, reduced equatorial precipitation, enhanced off-equatorial precipitation and an El Nino-like response a couple of years later, thus confirming the response to solar forcing at the surface seen in earlier studies. The amplitude of the solar signal in the Pacific region depends to a great extent on the choice of the centennial period averaged. Citation: Bal, S., S. Schimanke, T. Spangehl, and U. Cubasch (2011), On the robustness of the solar cycle signal in the Pacific region, Geophys. Res. Lett., 38, L14809, doi:10.1029/2011GL047964.

  • 2. Bal, Sourabh
    et al.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Spangehl, Thomas
    Cubasch, Ulrich
    Enhanced residual mean circulation during the evolution of split type sudden stratospheric warming in observations and model simulations2018Inngår i: Proceedings of the Indian Academy of Sciences, Earth and Planetary Sciences, ISSN 0253-4126, E-ISSN 0973-774X, Vol. 127, nr 5, artikkel-id 68Artikkel i tidsskrift (Fagfellevurdert)
  • 3. Bal, Sourabh
    et al.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Spangehl, Thomas
    Cubasch, Ulrich
    Variable influence on the equatorial troposphere associated with SSW using ERA-Interim2017Inngår i: Proceedings of the Indian Academy of Sciences, Earth and Planetary Sciences, ISSN 0253-4126, E-ISSN 0973-774X, Vol. 126, nr 2, artikkel-id UNSP 19Artikkel i tidsskrift (Fagfellevurdert)
  • 4. Boergel, Florian
    et al.
    Frauen, Claudia
    Neumann, Thomas
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Impact of the Atlantic Multidecadal Oscillation on Baltic Sea Variability2018Inngår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 45, nr 18, s. 9880-9888Artikkel i tidsskrift (Fagfellevurdert)
  • 5. 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, Forskningsavdelningen, Oceanografi.
    Storto, Andrea
    Tuma, Matthias
    Valisuo, Ilona
    Vaselali, Alireza
    ADVANCING GLOBAL AND REGIONAL REANALYSES2018Inngår i: Bulletin of The American Meteorological Society - (BAMS), ISSN 0003-0007, E-ISSN 1520-0477, Vol. 99, nr 8, s. ES139-ES144Artikkel i tidsskrift (Fagfellevurdert)
  • 6. Deng, Junjie
    et al.
    Harff, Jan
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    A method for assessing the coastline recession due to the sea level rise by assuming stationary wind-wave climate2015Inngår i: OCEANOLOGICAL AND HYDROBIOLOGICAL STUDIES, ISSN 1730-413X, Vol. 44, nr 3, s. 362-380Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The method introduced in this study for future projection of coastline changes hits the vital need of communicating the potential climate change impact on the coast in the 21th century. A quantitative method called the Dynamic Equilibrium Shore Model (DESM) has been developed to hindcast historical sediment mass budgets and to reconstruct a paleo Digital Elevation Model (DEM). The forward mode of the DESM model relies on paleo-scenarios reconstructed by the DESM model assuming stationary wind-wave climate. A linear relationship between the sea level, coastline changes and sediment budget is formulated and proven by the least square regression method. In addition to its forward prediction of coastline changes, this linear relationship can also estimate the sediment budget by using the information on the coastline and relative sea level changes. Wind climate change is examined based on regional climate model data. Our projections for the end of the 21st century suggest that the wind and wave climates in the southern Baltic Sea may not change compared to present conditions and that the investigated coastline along the Pomeranian Bay may retreat from 10 to 100 m depending on the location and on the sea level rise which was assumed to be in the range of 0.12 to 0.24 m.

  • 7.
    Dieterich, Christian
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Wang, Shiyu
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Väli, Germo
    SMHI, Forskningsavdelningen, Oceanografi.
    Liu, Ye
    SMHI, Forskningsavdelningen, Oceanografi.
    Hordoir, Robinson
    SMHI, Forskningsavdelningen, Oceanografi.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Evaluation of the SMHI coupled atmosphere-ice-ocean model RCA4-NEMO2013Rapport (Annet vitenskapelig)
    Abstract [sv]

    Den regionala kopplade atmosfär-is-havsmodellen RCA4-NEMO som utvecklats vid SMHI, utvärderas baserat på en ERA40-återanalys. Utvecklingen av den regionala klimatmodellen fortsätter men en första utvärdering presenteras här för att informera om aktuell status.RCA4-NEMO i aktuell status innehåller två modellkomponenter. Den regionala atmosfärsmodellen RCA4 täcker hela Europa och är tvåvägskopplad till en is-hav-modell för Nordsjön och Östersjön baserat på NEMO. Den används för tillfället för nedskalning av CMIP5-scenarier för detta århundrade för Nordsjön och Östersjön. Som en del av utvärderingen av RCA4-NEMO presenteras en analys och diskussion av hindcast-körning 1970-1999. Modellresulaten jämförs med observationsdata. Temperatur nära ytan och värmeflödet är förhållandevis bra vid en jämförelse med in-situ-mätningar och skattningar baserade på satellitdata. Salthalt och färskvattenutbyte är dock mindre bra. Momentumflödet från atmosfär till hav identifieras som en kritisk process i kopplingen mellan modellerna. Med undantag för färskvattensutbytet mellan atmosfär och hav är de klimatologiska egenskaperna nära ytan och motsvarande flöden jämförbara med klimatologiska observationer för perioden 1970-1999.

  • 8.
    Dieterich, Christian
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Wang, Shiyu
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Groger, Matthias
    SMHI, Forskningsavdelningen, Oceanografi.
    Klein, Birgit
    Hordoir, Robinson
    SMHI, Forskningsavdelningen, Oceanografi.
    Samuelsson, Patrick
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Liu, Ye
    SMHI, Forskningsavdelningen, Oceanografi.
    Axell, Lars
    SMHI, Forskningsavdelningen, Oceanografi.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Surface Heat Budget over the North Sea in Climate Change Simulations2019Inngår i: Atmosphere, ISSN 2073-4433, E-ISSN 2073-4433, Vol. 10, nr 5, artikkel-id 272Artikkel i tidsskrift (Fagfellevurdert)
  • 9. Groger, Matthias
    et al.
    Dieterich, Christian
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Thermal air-sea coupling in hindcast simulations for the North Sea and Baltic Sea on the NW European shelf2015Inngår i: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 67, artikkel-id 26911Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article compares interactively coupled atmosphere-ocean hindcast simulations with stand-alone runs of the atmosphere and ocean models using the recently developed regional ocean-atmosphere model NEMO-Nordic for the North Sea and Baltic Sea. In the interactively coupled run, the ocean and the atmosphere components were allowed to exchange mass, momentum and heat every 3 h. Our results show that interactive coupling significantly improves simulated winter sea surface temperatures (SSTs) in the Baltic Sea. The ocean and atmosphere stand-alone runs, respectively, resulted in too low sea surface and air temperatures over the Baltic Sea. These two runs suffer from too cold prescribed ERA40 SSTs, which lower air temperatures and weaken winds in the atmosphere only run. In the ocean-only run, the weaker winds additionally lower the vertical mixing thereby lowering the upward transport of warmer subpycnocline waters. By contrast, in the interactively coupled run, the ocean-atmosphere heat exchange evolved freely and demonstrated good skills in reproducing observed surface temperatures. Despite the strong impact on oceanic and atmospheric variables in the coupling area, no far reaching influence on atmospheric variables over land can be identified. In perturbation experiments, the different dynamics of the two coupling techniques is investigated in more detail by implementing strong positive winter temperature anomalies in the ocean model. Here, interactive coupling results in a substantially higher preservation of heat anomalies because the atmosphere also warmed which damped the ocean to atmosphere heat transfer. In the passively coupled set-up, this atmospheric feedback is missing, which resulted in an unrealistically high oceanic heat loss. The main added value of interactive air-sea coupling is twofold: (1) the elimination of any boundary condition at the air-sea interface and (2) the more realistic dynamical response to perturbations in the ocean-atmosphere heat balance, which will be essential in climate warming scenarios.

  • 10. Hood, Lon
    et al.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Spangehl, Thomas
    Bal, Sourabh
    Cubasch, Ulrich
    The Surface Climate Response to 11-Yr Solar Forcing during Northern Winter: Observational Analyses and Comparisons with GCM Simulations2013Inngår i: Journal of Climate, ISSN 0894-8755, E-ISSN 1520-0442, Vol. 26, nr 19, s. 7489-7506Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The surface climate response to 11-yr solar forcing during northern winter is first reestimated by applying a multiple linear regression (MLR) statistical model to Hadley Centre sea level pressure (SLP) and sea surface temperature (SST) data over the 1880-2009 period. In addition to a significant positive SLP response in the North Pacific found in previous studies, a positive SST response is obtained across the midlatitude North Pacific. Negative but insignificant SLP responses are obtained in the Arctic. The derived SLP response at zero lag therefore resembles a positive phase of the Arctic Oscillation (AO). Evaluation of the SLP and SST responses as a function of phase lag indicates that the response evolves from a negative AO-like mode a few years before solar maximum to a positive AO-like mode at and following solar maximum. For comparison, a similar MLR analysis is applied to model SLP and SST data from a series of simulations using an atmosphere-ocean general circulation model with a well-resolved stratosphere. The simulations differed only in the assumed solar cycle variation of stratospheric ozone. It is found that the simulation that assumed an ozone variation estimated from satellite data produces solar SLP and SST responses that are most consistent with the observational results, especially during a selected centennial period. In particular, a positive SLP response anomaly is obtained in the northeastern Pacific and a corresponding positive SST response anomaly extends across the midlatitude North Pacific. The model response versus phase lag also evolves from a mainly negative AO-like response before solar maximum to a mainly positive AO response at and following solar maximum.

  • 11.
    Hordoir, Robinson
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    An, B.W.
    SMHI.
    Haapala, J.
    SMHI.
    Dieterich, Christian
    SMHI, Forskningsavdelningen, Oceanografi.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    A 3D Ocean Modelling Configuration for Baltic & North Sea Exchange Analysis: BaltiX V 1.12013Rapport (Annet vitenskapelig)
    Abstract [en]

    There is a need for having a reliable numerical representation of the exchanges between the Baltic Sea and the North Sea from many points of view. First, the North Sea is the salt provider of the BalticSea, but also the oxygen provider of the lowermost layers of the Baltic Sea. This means that any numerical analysis which has for goal to study the long term changes in this exchange can not rely on a model of the Baltic Sea that has an open boundary condition at the entrance of the Baltic Sea (i.e.: the Kattegat area). In order to represent the long term changes in the exchanges between the NorthSea and the Baltic Sea, one needs to consider the coupling between these two basins which have a very different dynamical behaviour which means one needs to consider them as a whole. This meansthat any regional model should have its open boundary condition further away from the entrance of the Baltic Sea, that is in a place that is remote enough to allow a buffer large enough in the North Sea,so that the SSH variability at the entrance of the Baltic Sea is well represented [7].Second, the Baltic Sea outflow has a great influence on the Norwegian Coastal Current (NCC hereafter) which is also interesting to study, and which can only be well represented if the wind effect over the Baltic Sea is taken into account [9].Many models were successfully applied to the Baltic Sea or/and to the North Sea/Baltic Sea area. On can cite the Rossby Centre Ocean model RCO [15], which successfully represents the thermo-haline as well as the ice structures and variability of the Baltic Sea. One can also cite HIROMB [6], which is a North & Baltic Seas numerical representation used in operational oceanography.However, all these modelling structures lack in at least one of the following points :They include only the Baltic Sea area, which makes impossible the study of the exchanges withthe North Sea.- They were mostly used for operational purpose, and do not have stability properties in terms ofBaltic salt content which does not make them suitable for long term studies.- They do not follow anymore the framework of a community model, and therefore do not benefit of the recent scientific or technical developments implemented in most ocean modelling platform.- A Baltic & North Sea setup is also necessary for long term coupled simulations.There was therefore a need to build a new Baltic & North Sea configuration, based on a community modelling framework, and designed to follow this framework eventually.BaltiX is a Baltic & North Sea configuration based on the NEMO [14] ocean engine. Its development was started in 2011 at SMHI (Swedish Meteorological & Hydrological Institute, Norrköping, Sweden). It follows closely the development of the NEMO ocean engine, and BaltiX is updated each time an update is done in it.In the present report, Section 2 describes the configuration and explains the choices that have been made to build it. Based on a simulation done for the period 1961-2007, we then present several results. Section 3 presents a barotropic analysis of the results provided by the configuration, and Section 4 presents results in terms of salinity and temperature variability. Section 5 has been specifically written to present the sea-ice model coupled to BaltiX and its effects in terms of sea-ice variability. A last part provides a short conclusion to the present report.

  • 12.
    Hordoir, Robinson
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Axell, Lars
    SMHI, Forskningsavdelningen, Oceanografi.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Dieterich, Christian
    SMHI, Forskningsavdelningen, Oceanografi.
    Fransner, Filippa
    Groger, Matthias
    SMHI, Forskningsavdelningen, Oceanografi.
    Liu, Ye
    SMHI, Forskningsavdelningen, Oceanografi.
    Pemberton, Per
    SMHI, Forskningsavdelningen, Oceanografi.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Andersson, Helén
    SMHI, Forskningsavdelningen, Oceanografi.
    Ljungemyr, Patrik
    SMHI, Samhälle och säkerhet.
    Nygren, Petter
    SMHI, Samhälle och säkerhet.
    Falahat, Saeed
    SMHI, Samhälle och säkerhet.
    Nord, Adam
    SMHI, Samhälle och säkerhet.
    Jönsson, Anette
    SMHI, Samhälle och säkerhet.
    Lake, Irene
    SMHI, Samhälle och säkerhet. SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Doos, Kristofer
    Hieronymus, Magnus
    SMHI, Forskningsavdelningen, Oceanografi.
    Dietze, Heiner
    Loeptien, Ulrike
    Kuznetsov, Ivan
    Westerlund, Antti
    Tuomi, Laura
    Haapala, Jari
    Nemo-Nordic 1.0: a NEMO-based ocean model for the Baltic and North seas - research and operational applications2019Inngår i: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 12, nr 1, s. 363-386Artikkel i tidsskrift (Fagfellevurdert)
  • 13.
    Hordoir, Robinson
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Pemberton, Per
    SMHI, Forskningsavdelningen, Oceanografi.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Sensitivity of the overturning circulation of the Baltic Sea to climate change, a numerical experiment2018Inngår i: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 50, nr 3-4, s. 1425-1437Artikkel i tidsskrift (Fagfellevurdert)
  • 14.
    Höglund, Anders
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Pemberton, Per
    SMHI, Forskningsavdelningen, Oceanografi.
    Hordoir, Robinson
    SMHI, Forskningsavdelningen, Oceanografi.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Ice conditions for maritime traffic in the Baltic Sea in future climate2017Inngår i: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 22, s. 245-265Artikkel i tidsskrift (Fagfellevurdert)
  • 15.
    Koenigk, Torben
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Caian, Mihaela
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Nikulin, Grigory
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Regional Arctic sea ice variations as predictor for winter climate conditions2016Inngår i: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 46, nr 1-2, s. 317-337Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Seasonal prediction skill of winter mid and high northern latitudes climate from sea ice variations in eight different Arctic regions is analyzed using detrended ERA-interim data and satellite sea ice data for the period 1980-2013. We find significant correlations between ice areas in both September and November and winter sea level pressure, air temperature and precipitation. The prediction skill is improved when using November sea ice conditions as predictor compared to September. This is particularly true for predicting winter NAO-like patterns and blocking situations in the Euro-Atlantic area. We find that sea ice variations in Barents Sea seem to be most important for the sign of the following winter NAO-negative after low ice-but amplitude and extension of the patterns are modulated by Greenland and Labrador Seas ice areas. November ice variability in the Greenland Sea provides the best prediction skill for central and western European temperature and ice variations in the Laptev/East Siberian Seas have the largest impact on the blocking number in the Euro-Atlantic region. Over North America, prediction skill is largest using September ice areas from the Pacific Arctic sector as predictor. Composite analyses of high and low regional autumn ice conditions reveal that the atmospheric response is not entirely linear suggesting changing predictive skill dependent on sign and amplitude of the anomaly. The results confirm the importance of realistic sea ice initial conditions for seasonal forecasts. However, correlations do seldom exceed 0.6 indicating that Arctic sea ice variations can only explain a part of winter climate variations in northern mid and high latitudes.

  • 16. Kotilainen, Aarno T.
    et al.
    Arppe, Laura
    Dobosz, Slawomir
    Jansen, Eystein
    Kabel, Karoline
    Karhu, Juha
    Kotilainen, Mia M.
    Kuijpers, Antoon
    Lougheed, Bryan C.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Moros, Matthias
    Neumann, Thomas
    Porsche, Christian
    Poulsen, Niels
    Rasmussen, Peter
    Ribeiro, Sofia
    Risebrobakken, Bjorg
    Ryabchuk, Daria
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Snowball, Ian
    Spiridonov, Mikhail
    Virtasalo, Joonas J.
    Weckstrom, Kaarina
    Witkowski, Andrzej
    Zhamoida, Vladimir
    Echoes from the Past: A Healthy Baltic Sea Requires More Effort2014Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 43, nr 1, s. 60-68Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Integrated sediment multiproxy studies and modeling were used to reconstruct past changes in the Baltic Sea ecosystem. Results of natural changes over the past 6000 years in the Baltic Sea ecosystem suggest that forecasted climate warming might enhance environmental problems of the Baltic Sea. Integrated modeling and sediment proxy studies reveal increased sea surface temperatures and expanded seafloor anoxia (in deep basins) during earlier natural warm climate phases, such as the Medieval Climate Anomaly. Under future IPCC scenarios of global warming, there is likely no improvement of bottom water conditions in the Baltic Sea. Thus, the measures already designed to produce a healthier Baltic Sea are insufficient in the long term. The interactions between climate change and anthropogenic impacts on the Baltic Sea should be considered in management, implementation of policy strategies in the Baltic Sea environmental issues, and adaptation to future climate change.

  • 17.
    Kuznetsov, Ivan
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Dieterich, Christian
    SMHI, Forskningsavdelningen, Oceanografi.
    Hordoir, Robinson
    SMHI, Forskningsavdelningen, Oceanografi.
    Axell, Lars
    SMHI, Forskningsavdelningen, Oceanografi.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Model study on the variability of ecosystem parameters in the Skagerrak-Kattegat area, effect of load reduction in the North Sea and possible effect of BSAP on Skagerrak-Kattegat area2016Rapport (Annet vitenskapelig)
    Abstract [en]

    Newly developed ecosystem model NEMO-Nordic-SCOBI was applied to Skagerrak - Kattegat area to investigate the variability of some indicators of the ecosystem. Also, two sensitivity runs were performed to investigate possible effect of the Baltic Sea Action Plan (BSAP) and a river loads reduction scenario on the Skagerrak - Kattegat area. The performed investigation could be used “to provide a basis to assist with the interpretation of measurement data before the Intermediate Assessments Eutrophication status assessment”. Comparison of simulation results with observations indicates acceptable model performance. Modeled sea surface salinity, temperature and dissolved inorganic phosphate (DIP) are in good agreement with observations. At the same time, the model has a bias in certain areas of the investigated region for dissolved inorganic nitrogen (DIN) and dissolved silicate during the winter season. However, the model in its current state shows good enough results for the performed investigation. Results of the two sensitivity studies show a decrease of sea surface nutrients concentrations during winter period in both regions. In the Skagerrak area the decrease is due to reduction in river nutrient loads in North Sea. In the Kattegat area there is a decrease of dissolved phosphate due to the implementation of BSAP. At the same time, in both scenarios, no significant changes were obtained for near bottom oxygen or surface layer Chl-a.

  • 18.
    Meier, Markus
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Andersson, Helén
    SMHI, Forskningsavdelningen, Oceanografi.
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Blenckner, Thorsten
    Chubarenko, Boris
    Donnelly, Chantal
    SMHI, Forskningsavdelningen, Hydrologi.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Gustafsson, Bo G.
    Hansson, Anders
    Havenhand, Jonathan
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Kuznetsov, Ivan
    MacKenzie, Brian R.
    Muller-Karulis, Barbel
    Neumann, Thomas
    Niiranen, Susa
    Piwowarczyk, Joanna
    Raudsepp, Urmas
    Reckermann, Marcus
    Ruoho-Airola, Tuija
    Savchuk, Oleg P.
    Schenk, Frederik
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Vali, Germo
    Weslawski, Jan-Marcin
    Zorita, Eduardo
    Comparing reconstructed past variations and future projections of the Baltic Sea ecosystem-first results from multi-model ensemble simulations2012Inngår i: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 7, nr 3, artikkel-id 034005Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Multi-model ensemble simulations for the marine biogeochemistry and food web of the Baltic Sea were performed for the period 1850-2098, and projected changes in the future climate were compared with the past climate environment. For the past period 1850-2006, atmospheric, hydrological and nutrient forcings were reconstructed, based on historical measurements. For the future period 1961-2098, scenario simulations were driven by regionalized global general circulation model (GCM) data and forced by various future greenhouse gas emission and air-and riverborne nutrient load scenarios (ranging from a pessimistic 'business-as-usual' to the most optimistic case). To estimate uncertainties, different models for the various parts of the Earth system were applied. Assuming the IPCC greenhouse gas emission scenarios A1B or A2, we found that water temperatures at the end of this century may be higher and salinities and oxygen concentrations may be lower than ever measured since 1850. There is also a tendency of increased eutrophication in the future, depending on the nutrient load scenario. Although cod biomass is mainly controlled by fishing mortality, climate change together with eutrophication may result in a biomass decline during the latter part of this century, even when combined with lower fishing pressure. Despite considerable shortcomings of state-of-the-art models, this study suggests that the future Baltic Sea ecosystem may unprecedentedly change compared to the past 150 yr. As stakeholders today pay only little attention to adaptation and mitigation strategies, more information is needed to raise public awareness of the possible impacts of climate change on marine ecosystems.

  • 19.
    Meier, Markus
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Andersson, Helén
    SMHI, Forskningsavdelningen, Oceanografi.
    Dieterich, Christian
    SMHI, Forskningsavdelningen, Oceanografi.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Gustafsson, B.
    Stockholm Resilience Centre/Baltic Nest Institute, Stockholm University, Stockholm, Sweden.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Transient scenario simulations for the Baltic Sea Region during the 21st century2011Rapport (Annet vitenskapelig)
    Abstract [sv]

    Vattnet i Östersjön är optiskt sett uppdelat i många beståndsdelar och har ytterst höga halter av färgade lösta organiska ämnen (colored dissolved organic matter, CDOM), även kallade för gulämnen, gilvin eller gelbstoff. CDOM är en komplex blandning av kemiska bindningar skapade vid nedbrytningen av fotosyntetiskt producerat organiskt material och det har en avsevärd påverkan på ljusfältet i vattnet. En kvantitativ beskrivning av dynamiken och variabiliteten behövs ofta för att få en riktig beskrivning av ljusets nedträngning och därefter av tex primärproduktionen.     
    Denna studie är ett första försök att inkludera CDOM i en modell för Östersjön. Modellförsöken baseras på en fix koncentration i de 30 största floderna. I brist på omfattande mätningar antas en flodtillförsel som är proportionell mot totalt organiskt kol. Eftersom ursprunget och ödet fortfarande är föremål för diskussioner testar vi olika hastigheter av CDOM sönderfall och jämför resultaten med satellitobservationer. Jämfört med temperatur eller tidsberoende sönderfall uppnåddes bäst resultat med ett ljusberoende sönderfall. Att behandla CDOM som ett konservativt spårämne leder inte till tillfredsställande resultat.

  • 20.
    Meier, Markus
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Almroth-Rosell, E.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Kniebusch, M.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Pemberton, Per
    SMHI, Forskningsavdelningen, Oceanografi.
    Liu, Ye
    SMHI, Forskningsavdelningen, Oceanografi.
    Väli, Germo
    SMHI, Forskningsavdelningen, Oceanografi.
    Saraiva, S.
    Disentangling the impact of nutrient load and climate changes on Baltic Sea hypoxia and eutrophication since 1850 (vol 53, pg 1145, 2019)2019Inngår i: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 53, nr 1-2, s. 1167-1169Artikkel i tidsskrift (Fagfellevurdert)
  • 21.
    Meier, Markus
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Almroth-Rosell, Elin
    SMHI, Forskningsavdelningen, Oceanografi.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Kniebusch, M.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Pemberton, Per
    SMHI, Forskningsavdelningen, Oceanografi.
    Liu, Ye
    SMHI, Forskningsavdelningen, Oceanografi.
    Väli, Germo
    SMHI, Forskningsavdelningen, Oceanografi.
    Saraiva, S.
    Disentangling the impact of nutrient load and climate changes on Baltic Sea hypoxia and eutrophication since 18502019Inngår i: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 53, nr 1-2, s. 1145-1166Artikkel i tidsskrift (Fagfellevurdert)
  • 22.
    Meier, Markus
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Hordoir, Robinson
    SMHI, Forskningsavdelningen, Oceanografi.
    Andersson, Helén
    SMHI, Forskningsavdelningen, Oceanografi.
    Dieterich, Christian
    SMHI, Forskningsavdelningen, Oceanografi.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Gustafsson, B. G.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Modeling the combined impact of changing climate and changing nutrient loads on the Baltic Sea environment in an ensemble of transient simulations for 1961-20992012Inngår i: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 39, nr 9-10, s. 2421-2441Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The combined future impacts of climate change and industrial and agricultural practices in the Baltic Sea catchment on the Baltic Sea ecosystem were assessed. For this purpose 16 transient simulations for 1961-2099 using a coupled physical-biogeochemical model of the Baltic Sea were performed. Four climate scenarios were combined with four nutrient load scenarios ranging from a pessimistic business-as-usual to a more optimistic case following the Baltic Sea Action Plan (BSAP). Annual and seasonal mean changes of climate parameters and ecological quality indicators describing the environmental status of the Baltic Sea like bottom oxygen, nutrient and phytoplankton concentrations and Secchi depths were studied. Assuming present-day nutrient concentrations in the rivers, nutrient loads from land increase during the twenty first century in all investigated scenario simulations due to increased volume flows caused by increased net precipitation in the Baltic catchment area. In addition, remineralization rates increase due to increased water temperatures causing enhanced nutrient flows from the sediments. Cause-and-effect studies suggest that both processes may play an important role for the biogeochemistry of eutrophicated seas in future climate partly counteracting nutrient load reduction efforts like the BSAP.

  • 23.
    Meier, Markus
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Muller-Karulis, Barbel
    Andersson, Helén
    SMHI, Forskningsavdelningen, Oceanografi.
    Dieterich, Christian
    SMHI, Forskningsavdelningen, Oceanografi.
    Eilola, Kari
    SMHI, Forskningsavdelningen, Oceanografi.
    Gustafsson, Bo G.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Hordoir, Robinson
    SMHI, Forskningsavdelningen, Oceanografi.
    Kuznetsov, Ivan
    SMHI, Forskningsavdelningen, Oceanografi.
    Neumann, Thomas
    Ranjbar, Zohreh
    Savchuk, Oleg P.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Impact of Climate Change on Ecological Quality Indicators and Biogeochemical Fluxes in the Baltic Sea: A Multi-Model Ensemble Study2012Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, nr 6, s. 558-573Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Multi-model ensemble simulations using three coupled physical-biogeochemical models were performed to calculate the combined impact of projected future climate change and plausible nutrient load changes on biogeochemical cycles in the Baltic Sea. Climate projections for 1961-2099 were combined with four nutrient load scenarios ranging from a pessimistic business-as-usual to a more optimistic case following the Helsinki Commission's (HELCOM) Baltic Sea Action Plan (BSAP). The model results suggest that in a future climate, water quality, characterized by ecological quality indicators like winter nutrient, summer bottom oxygen, and annual mean phytoplankton concentrations as well as annual mean Secchi depth (water transparency), will be deteriorated compared to present conditions. In case of nutrient load reductions required by the BSAP, water quality is only slightly improved. Based on the analysis of biogeochemical fluxes, we find that in warmer and more anoxic waters, internal feedbacks could be reinforced. Increased phosphorus fluxes out of the sediments, reduced denitrification efficiency and increased nitrogen fixation may partly counteract nutrient load abatement strategies.

  • 24.
    Pemberton, Per
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Löptien, Ulrike
    SMHI, Forskningsavdelningen, Oceanografi.
    Hordoir, Robinson
    SMHI, Forskningsavdelningen, Oceanografi.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Axell, Lars
    SMHI, Forskningsavdelningen, Oceanografi.
    Haapala, Jari
    Sea-ice evaluation of NEMO-Nordic 1.0: a NEMO-LIM3.6-based ocean-sea-ice model setup for the North Sea and Baltic Sea2017Inngår i: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 10, nr 8, s. 3105-3123Artikkel i tidsskrift (Fagfellevurdert)
  • 25.
    Schimanke, Semjon
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Dieterich, Christian
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    An algorithm based on sea-level pressure fluctuations to identify major Baltic inflow events2014Inngår i: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 66, artikkel-id 23452Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Major Baltic inflows are an important process to sustain the sensitive steady state of the Baltic Sea. We introduce an algorithm to identify atmospheric variability favourable for major Baltic inflows. The algorithm is based on sea-level pressure (SLP) fields as the only parameter. Characteristic SLP pattern fluctuations include a precursory phase of 30 days and 10 days of inflow period. The algorithm identifies successfully the majority of observed major Baltic inflows between 1961 and 2010. In addition, the algorithm finds some occurrences which cannot be related to observed inflows. In these cases with favourable atmospheric conditions, inflows were precluded by contemporaneously existing saline water masses or strong freshwater supply. Moreover, the algorithm clearly identifies the stagnation periods as a lack of SLP variability favourable for MBIs. This indicates that the lack of inflows is mainly a consequence of missing atmospheric forcing during this period. The only striking inflow which is not identified by the algorithm is the event in January 2003. We demonstrate that this is due to the special evolution of SLP fields which are not comparable with any other event. Finally, the algorithm is applied to an ensemble of scenario simulations. The result indicates that the number of atmospheric events favourable for major Baltic inflows increases slightly in all scenarios.

  • 26.
    Schimanke, Semjon
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Strandberg, Gustav
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    A regional climate model simulation over the Baltic Sea region for the last Millennium2011Rapport (Annet vitenskapelig)
    Abstract [sv]

    Variabilitet och långsiktig klimatförändring i Fennoskandien undersöks i en 1000 år lång under det senaste milleniet i en 1000 år lång klimatmodellsimulering. Vi använder Rossby Centres regionala klimatmodell (RCA3) med randvärden från en global klimatmodell (GCM). Effekten av variabilitet i solinstrålning, ändrade astronomiska förhållanden och ändringar i växthusgskoncentrationer har använts för att driva modellerna. Resultaten visar att RCA3 genererar en medeltida varm period (MCA) som är den varmaste under hela milleniet undantaget 1900-talet. Dessutom visar resultaten på en kall ”Lilla Istid” (LIA). I simuleringen motsvarar dessa perioder 1100- 1299 (MCA) samt 1600-1799 (LIA). Det här överensstämmer med rekonstruktioner och kan till största delen relateras till ändringar i solinstrålning. Vi fann vidare att variabiliteten över flera decennier har en betydande effekt på klimatet under MCA och LIA. Variabiliteten över flera decennier kan ibland också förklara motsägelsefulla rekonstruktioner om dessa är representativa för kortare icke sammanfallande perioder. I tillägg till tidsserier, undersöker vi också rumsliga mönster hos temperatur, lufttryck i havsytans nivå, nederbörd, molntäcke, vindhastighet och byighet för både säsongs- och årsmedelvärden. De flesta parametrarna visar störst skillnad mellan olika perioder för vintersäsongen. Som exempel kan nämnas att vintern under MCA var 1-2.5 K varmare än under LIA sett som medelvärde över flera decennier. Variabilitet och långsiktig klimatförändring i Fennoskandien undersöks i en 1000 år lång under det senaste milleniet i en 1000 år lång klimatmodellsimulering. Vi använder Rossby Centres regionala klimatmodell (RCA3) med randvärden från en global klimatmodell (GCM). Effekten av variabilitet i solinstrålning, ändrade astronomiska förhållanden och ändringar i växthusgskoncentrationer har använts för att driva modellerna. Resultaten visar att RCA3 genererar en medeltida varm period (MCA) som är den varmaste under hela milleniet undantaget 1900-talet. Dessutom visar resultaten på en kall ”Lilla Istid” (LIA). I simuleringen motsvarar dessa perioder 1100- 1299 (MCA) samt 1600-1799 (LIA). Det här överensstämmer med rekonstruktioner och kan till största delen relateras till ändringar i solinstrålning. Vi fann vidare att variabiliteten över flera decennier har en betydande effekt på klimatet under MCA och LIA. Variabiliteten över flera decennier kan ibland också förklara motsägelsefulla rekonstruktioner om dessa är representativa för kortare icke sammanfallande perioder. I tillägg till tidsserier, undersöker vi också rumsliga mönster hos temperatur, lufttryck i havsytans nivå, nederbörd, molntäcke, vindhastighet och byighet för både säsongs- och årsmedelvärden. De flesta parametrarna visar störst skillnad mellan olika perioder för vintersäsongen. Som exempel kan nämnas att vintern under MCA var 1-2.5 K varmare än under LIA sett som medelvärde över flera decennier. Variabilitet och långsiktig klimatförändring i Fennoskandien undersöks i en 1000 år lång under det senaste milleniet i en 1000 år lång klimatmodellsimulering. Vi använder Rossby Centres regionala klimatmodell (RCA3) med randvärden från en global klimatmodell (GCM). Effekten av variabilitet i solinstrålning, ändrade astronomiska förhållanden och ändringar i växthusgskoncentrationer har använts för att driva modellerna. Resultaten visar att RCA3 genererar en medeltida varm period (MCA) som är den varmaste under hela milleniet undantaget 1900-talet. Dessutom visar resultaten på en kall ”Lilla Istid” (LIA). I simuleringen motsvarar dessa perioder 1100- 1299 (MCA) samt 1600-1799 (LIA). Det här överensstämmer med rekonstruktioner och kan till största delen relateras till ändringar i solinstrålning. Vi fann vidare att variabiliteten över flera decennier har en betydande effekt på klimatet under MCA och LIA. Variabiliteten över flera decennier kan ibland också förklara motsägelsefulla rekonstruktioner om dessa är representativa för kortare icke sammanfallande perioder. I tillägg till tidsserier, undersöker vi också rumsliga mönster hos temperatur, lufttryck i havsytans nivå, nederbörd, molntäcke, vindhastighet och byighet för både säsongs- och årsmedelvärden. De flesta parametrarna visar störst skillnad mellan olika perioder för vintersäsongen. Som exempel kan nämnas att vintern under MCA var 1-2.5 K varmare än under LIA sett som medelvärde över flera decennier. Variabilitet och långsiktig klimatförändring i Fennoskandien undersöks i en 1000 år lång under det senaste milleniet i en 1000 år lång klimatmodellsimulering. Vi använder Rossby Centres regionala klimatmodell (RCA3) med randvärden från en global klimatmodell (GCM). Effekten av variabilitet i solinstrålning, ändrade astronomiska förhållanden och ändringar i växthusgskoncentrationer har använts för att driva modellerna. Resultaten visar att RCA3 genererar en medeltida varm period (MCA) som är den varmaste under hela milleniet undantaget 1900-talet. Dessutom visar resultaten på en kall ”Lilla Istid” (LIA). I simuleringen motsvarar dessa perioder 1100- 1299 (MCA) samt 1600-1799 (LIA). Det här överensstämmer med rekonstruktioner och kan till största delen relateras till ändringar i solinstrålning. Vi fann vidare att variabiliteten över flera decennier har en betydande effekt på klimatet under MCA och LIA. Variabiliteten över flera decennier kan ibland också förklara motsägelsefulla rekonstruktioner om dessa är representativa för kortare icke sammanfallande perioder. I tillägg till tidsserier, undersöker vi också rumsliga mönster hos temperatur, lufttryck i havsytans nivå, nederbörd, molntäcke, vindhastighet och byighet för både säsongs- och årsmedelvärden. De flesta parametrarna visar störst skillnad mellan olika perioder för vintersäsongen. Som exempel kan nämnas att vintern under MCA var 1-2.5 K varmare än under LIA sett som medelvärde över flera decennier.

  • 27.
    Schimanke, Semjon
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Decadal-to-Centennial Variability of Salinity in the Baltic Sea2016Inngår i: Journal of Climate, ISSN 0894-8755, E-ISSN 1520-0442, Vol. 29, nr 20, s. 7173-7188Artikkel i tidsskrift (Fagfellevurdert)
  • 28.
    Schimanke, Semjon
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Strandberg, Gustav
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Hordoir, Robinson
    SMHI, Forskningsavdelningen, Oceanografi.
    The climate in the Baltic Sea region during the last millennium simulated with a regional climate model2012Inngår i: Climate of the Past, ISSN 1814-9324, E-ISSN 1814-9332, Vol. 8, nr 5, s. 1419-1433Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Variability and long-term climate change in the Baltic Sea region is investigated for the pre-industrial period of the last millennium. For the first time dynamical down-scaling covering the complete millennium is conducted with a regional climate model in this area. As a result of changing external forcing conditions, the model simulation shows warm conditions in the first centuries followed by a gradual cooling until ca. 1700 before temperature increases in the last centuries. This long-term evolution, with a Medieval Climate Anomaly (MCA) and a Little Ice Age (LIA), is in broad agreement with proxy-based reconstructions. However, the timing of warm and cold events is not captured at all times. We show that the regional response to the global climate anomalies is to a strong degree modified by the large-scale circulation in the model. In particular, we find that a positive phase of the North Atlantic Oscillation (NAO) simulated during MCA contributes to enhancing winter temperatures and precipitation in the region while a negative NAO index in the LIA reduces them. In a second step, the regional ocean model (RCO-SCOBI) is used to investigate the impact of atmospheric changes onto the Baltic Sea for two 100 yr time slices representing the MCA and the LIA. Besides the warming of the Baltic Sea, the water becomes fresher at all levels during the MCA. This is induced by increased runoff and stronger westerly winds. Moreover, the oxygen concentrations in the deep layers are slightly reduced during the MCA. Additional sensitivity studies are conducted to investigate the impact of even higher temperatures and increased nutrient loads. The presented experiments suggest that changing nutrient loads may be more important determining oxygen depletion than changes in temperature or dynamic feedbacks.

  • 29.
    Schimanke, Semjon
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Spangehl, T.
    Huebener, H.
    Cubasch, U.
    Variability and trends of major stratospheric warmings in simulations under constant and increasing GHG concentrations2013Inngår i: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 40, nr 7-8, s. 1733-1747Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ensemble simulations with a coupled ocean-troposphere-stratosphere model for the pre-industrial era (1860 AD), late twentieth century (1990 AD) greenhouse gas (GHG) concentrations, the SRES scenarios B1, A1B, A2, as well as stabilization experiments up to the Twenty-third century with B1 and A1B scenario GHG concentrations at their values at 2100, have been analyzed with regard to the occurrence of major sudden stratospheric warmings (SSWs). An automated algorithm using 60A degrees N and 10 hPa zonal wind and the temperature gradient between 60A degrees N and the North Pole is used to identify this phenomenon in the large data set. With 1990 CO2 concentrations (352 ppmv), the frequency of simulated SSWs in February and March is comparable to observation, but they are underestimated during November to January. All simulations show an increase in the number of SSWs from the pre-industrial period to the end of the twenty-first century, indicating that the increase of GHG is also reflected in the number of sudden warmings. However, a high variability partially masks the underlying trend. Multi-century averages during the stabilization periods indicate that the increase of SSWs is linear to the applied radiative forcing. A doubling of SSWs occurs when the GHG concentration reaches the level of the A2 scenario at the end of the twenty-first century (836 ppmv). The increase in SSWs in the projections is caused by a combination of increased wave flux from the troposphere and weaker middle atmospheric zonal winds.

  • 30.
    Schöld, Sofie
    et al.
    SMHI, Samhälle och säkerhet.
    Hellström, Sverker
    SMHI, Samhälle och säkerhet.
    Ivarsson, Cajsa-Lisa
    SMHI, Affärsverksamhet.
    Kållberg, Per
    SMHI, Forskningsavdelningen, Meteorologi.
    Lindow, Helma
    SMHI, Samhälle och säkerhet.
    Nerheim, Signild
    SMHI, Affärsverksamhet.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Södling, Johan
    SMHI, Affärsverksamhet.
    Wern, Lennart
    SMHI, Samhälle och säkerhet.
    Vattenståndsdynamik längs Sveriges kust2018Rapport (Annet vitenskapelig)
    Abstract [sv]

    För att skapa ett samhälle väl anpassat till dagens och framtidens havsnivåer behövs besluts- och planeringsunderlag. Skyddsåtgärder och designnivåer för kustskydd är högaktuella frågor och många aktörer är intresserade av information kring potentiella maxnivåer för vattenstånd på olika tidshorisonter. SMHI har därför analyserat de mätdataserier för havsvattenstånd som idag finns tillgängliga från stationer längs Sveriges kust. Det primära syftet var att ta fram en metod för att beräkna det högsta möjliga havsvattenståndet vid mätstationer längs Sveriges kust. Metoden beskrivs i Schöld m.fl.(2017).

    I föreliggande rapport beskrivs allmänt havsnivåer, mätdata, modeller och de resultat som erhölls från olika analyser av mätdata. Mätstationerna indelades i åtta olika kustområden inom vilka vattenståndet samvarierar. Det väder och de specifika stormbanor, som under de senaste 40 åren orsakat de högsta stormfloderna på olika platser längs den svenska kusten kartlades, och vattenståndsdynamiken vid olika mätstationer studerades.

    Kortvariga höjningar av vattenståndet undersöktes, både med avseende på kraftiga vattenståndshöjningar orsakade av passerande väderssystem och med avseende på förhöjda utgångslägen, som i sin tur kan bidra till att stormfloder blir extra höga.

    Det högsta beräknade havsvattenstånd som presenteras är de högsta möjliga stormfloder som skulle kunna inträffa baserat på empiriska analyser av mätdata vid de olika stationerna. Kända extrema händelser, som ägt rum före det att vattenståndet började registreras, ingår inte eftersom de inte har kunnat kvantifieras. Framtida förändringar av medelvattenståndet orsakade av den globala klimatförändringen behandlas inte i denna rapport.

    Resultaten från studien visar att vattennivåerna i Östersjön generellt blir som högst i Bottenviken och i de södra delarna. De höga vattenstånden i större delen av Östersjön är inte lika höga som på västkusten och i Öresund. I Östersjön förefaller också utgångsläget, havsnivån före stormen, utgöra en större del av den resulterande vattenståndshöjningen. Vid flera stationer i de centrala delarna av Östersjön är havsnivån före storm i stort sett hälften av det högsta beräknade havsvattenståndet. Längs västkusten är istället de nettohöjningar som orsakas av rena stormeffekter den viktigaste stormflodskomponenten. Lokala förhållanden, till exempel om stationen är belägen vid en öppen, rak kust eller inne i en vik, påverkar hur högt vattenståndet kan förväntas bli på en viss plats.

    Analyserna visar att stormfloder skulle kunna bli omkring 20-40 cm högre än hittills observerade maximala nivåer i olika kustområden. En osäkerhetsmarginal på runt +15 cm är lämplig att addera, särskilt i de områden där tidvatten förekommer.

  • 31.
    Wang, Shiyu
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Dieterich, Christian
    SMHI, Forskningsavdelningen, Oceanografi.
    Doescher, Ralf
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Höglund, Anders
    SMHI, Forskningsavdelningen, Oceanografi.
    Hordoir, Robinson
    SMHI, Forskningsavdelningen, Oceanografi.
    Meier, Markus
    SMHI, Forskningsavdelningen, Oceanografi.
    Samuelsson, Patrick
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Schimanke, Semjon
    SMHI, Forskningsavdelningen, Oceanografi.
    Development and evaluation of a new regional coupled atmosphere-ocean model in the North Sea and Baltic Sea2015Inngår i: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 67, artikkel-id 24284Artikkel i tidsskrift (Fagfellevurdert)
    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.

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