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  • 301. Miranda, A.I
    et al.
    Martins, Helena
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Valente, J.
    Amorim, Jorge Humberto
    SMHI, Forskningsavdelningen, Luftmiljö.
    Borrego, C.
    Tavares, R.
    Samson, R.
    del Amo, R.A.
    Case Studies: Modeling the Atmospheric Benefits of Urban Greening2017Ingår i: The Urban Forest - Cultivating Green Infrastructure for People and the Environment / [ed] D. Pearlmutter, C. Calfapietra, R. Samson, L. O'Brien, S.K. Ostoić, G. Sanesi, R.A. del Amo, Springer International Publishing , 2017, s. 89-99Kapitel i bok, del av antologi (Refereegranskat)
  • 302.
    Moberg, Anders
    et al.
    Department of Physical Geography and Quaternary Geology, Stockholm University Department of Meteorology, Stockholm University.
    Gouirand, Isabelle
    Department of Physical Geography and Quaternary Geology, Stockholm University .
    Schoning, Kristian
    Department of Physical Geography and Quaternary Geology, Stockholm University .
    Wohlfarth, Barbara
    Department of Physical Geography and Quaternary Geology, Stockholm University.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Rummukainen, Markku
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    de Jong, Rixt
    Department of Quaternary Geology, Lund University.
    Linderholm, Hans
    Department of Earth Sciences, Göteborg University .
    Zorita, Eduardo
    GKSS Research Centre, Geesthacht, Germany.
    Climate in Sweden during the past millennium – Evidence from proxy data, instrumental data and model simulations2006Rapport (Övrigt vetenskapligt)
  • 303.
    Moen, Lars
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    A multi-level quasi-geostrophic model for short range weather predictions1975Rapport (Övrigt vetenskapligt)
    Abstract [en]

    A quite generally formulated multilevel quasi-geostrophic medel with possibilities to include second order terms in the vorticity equation is derived. The model includes friction, topography, latent heat and sensible heat. The treatment of the variable boundary conditions, smoothing and ellipticity control is described.

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  • 304. Moore, Karen
    et al.
    Pierson, Donald
    Pettersson, Kurt
    Schneiderman, Elliot
    Samuelsson, Patrick
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Effects of warmer world scenarios on hydrologic inputs to Lake Malaren, Sweden and implications for nutrient loads2008Ingår i: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 599, s. 191-199Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A simple, rapid, and flexible modelling approach was applied to explore the impacts of climate change on hydrologic inputs and consequent implications for nutrient loading to Lake Malaren, Sweden using a loading function model (GWLF). The first step in the process was to adapt the model for use in a large and complex Swedish catchment. We focused on the Galten basin with four rivers draining into the western region of Malaren. The catchment model was calibrated and tested using long-term historical data for river discharge and dissolved nutrients (N, P). Then multiple regional climate model simulation results were downscaled to the local catchment level, and used to simulate possible hydrological and nutrient loading responses to warmer world scenarios. Climate change projections for the rivers of Galten basin show profound changes in the timing of discharge and nutrient delivery due to increased winter precipitation and earlier snow melt. Impacts on total annual discharge and load are minimal, but the alteration in river flow regime and the timing of nutrient delivery for future climate scenarios is strikingly different from historical conditions.

  • 305. Moseley, Christopher
    et al.
    Berg, Peter
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Haerter, Jan O.
    Probing the precipitation life cycle by iterative rain cell tracking2013Ingår i: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 118, nr 24, s. 13361-13370Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Monitoring the life cycle of convective rain cells requires a Lagrangian viewpoint where the observer moves with the dominant background flow. To adopt such a moving reference frame, we design, validate, and apply a simple rain cell tracking methodwhich we term iterative rain cell tracking (IRT)for spatio-temporal precipitation data. IRT iteratively identifies the formation and dissipation of rain cells and determines the large-scale flow. The iteration is repeated until reaching convergence. As validated using reanalysis wind speeds, repeated iterations lead to substantially increased agreement of the background flow field and an increased number of complete tracks. Our method is thereby able to monitor the growth and intensity profiles of rain cells and is applied to a high-resolution (5 min and 1x1 km(2)) data set of radar-derived rainfall intensities over Germany. We then combine this data set with surface temperature observations and synoptic observations to group tracks according to convective and stratiform conditions. Convective tracks show clear life cycles in intensity, with peaks shifted off-center toward the beginning of the track, whereas stratiform tracks have comparatively featureless intensity profiles. Our results show that the convective life cycle can lead to convection-dominating precipitation extremes at short time scales, while track-mean intensities may vary much less between the two types. The observed features become more pronounced as surface temperature increases, and in the case of convection even exceeded the rates expected from the Clausius-Clapeyron relation.

  • 306. Napoly, Adrien
    et al.
    Boone, Aaron
    Samuelsson, Patrick
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Gollvik, Stefan
    SMHI.
    Martin, Eric
    Seferian, Roland
    Carrer, Dominique
    Decharme, Bertrand
    Jarlan, Lionel
    The interactions between soil-biosphere-atmosphere (ISBA) land surface model multi-energy balance (MEB) option in SURFEXv8-Part 2: Introduction of a litter formulation and model evaluation for local-scale forest sites2017Ingår i: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 10, nr 4, s. 1621-1644Artikel i tidskrift (Refereegranskat)
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  • 307. Nasr, Amro
    et al.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Bjornsson, Ivar
    Honfi, Daniel
    Ivanov, Oskar L.
    Johansson, Jonas
    Bridges in a changing climate: a study of the potential impacts of climate change on bridges and their possible adaptations2020Ingår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 16, nr 4, s. 738-749Artikel i tidskrift (Refereegranskat)
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  • 308. Naumann, G.
    et al.
    Alfieri, L.
    Wyser, Klaus
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Mentaschi, L.
    Betts, R. A.
    Carrao, H.
    Spinoni, J.
    Vogt, J.
    Feyen, L.
    Global Changes in Drought Conditions Under Different Levels of Warming2018Ingår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 45, nr 7, s. 3285-3296Artikel i tidskrift (Refereegranskat)
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  • 309. Navarro-Ortega, Alicia
    et al.
    Acuna, Vicenc
    Bellin, Alberto
    Burek, Peter
    Cassiani, Giorgio
    Choukr-Allah, Redouane
    Doledec, Sylvain
    Elosegi, Arturo
    Ferrari, Federico
    Ginebreda, Antoni
    Grathwohl, Peter
    Jones, Colin
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Rault, Philippe Ker
    Kok, Kasper
    Koundouri, Phoebe
    Ludwig, Ralf Peter
    Merz, Ralf
    Milacic, Radmila
    Munoz, Isabel
    Nikulin, Grigory
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Paniconi, Claudio
    Paunovic, Momir
    Petrovic, Mira
    Sabater, Laia
    Sabater, Sergi
    Skoulikidis, Nikolaos Th.
    Slob, Adriaan
    Teutsch, Georg
    Voulvoulis, Nikolaos
    Barcelo, Damia
    Managing the effects of multiple stressors on aquatic ecosystems under water scarcity. The GLOBAQUA project2015Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 503, s. 3-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Water scarcity is a serious environmental problem in many European regions, and will likely increase in the near future as a consequence of increased abstraction and climate change. Water scarcity exacerbates the effects of multiple stressors, and thus results in decreased water quality. It impacts river ecosystems, threatens the services they provide, and it will force managers and policy-makers to change their current practices. The EU-FP7 project GLOBAQUA aims at identifying the prevalence, interaction and linkages between stressors, and to assess their effects on the chemical and ecological status of freshwater ecosystems in order to improve water management practice and policies. GLOBAQUA assembles a multidisciplinary team of 21 European plus 2 non-European scientific institutions, as well as water authorities and river basin managers. The project includes experts in hydrology, chemistry, biology, geomorphology, modelling, socio-economics, governance science, knowledge brokerage, and policy advocacy. GLOBAQUA studies six river basins (Ebro, Adige, Sava, Evrotas, Anglian and Souss Massa) affected by water scarcity, and aims to answer the following questions: how does water scarcity interact with other existing stressors in the study river basins? How will these interactions change according to the different scenarios of future global change? Which will be the foreseeable consequences for river ecosystems? How will these in turn affect the services the ecosystems provide? How should management and policies be adapted to minimise the ecological, economic and societal consequences? These questions will be approached by combining data-mining, field- and laboratory-based research, and modelling. Here, we outline the general structure of the project and the activities to be conducted within the fourteen work-packages of GLOBAQUA. (C) 2014 The Authors. Published by Elsevier B.V.

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  • 310. Nijssen, B
    et al.
    Bowling, L C
    Lettenmaier, D P
    Clark, D B
    El Maayar, M
    Essery, R
    Goers, S
    Gusev, Y M
    Habets, F
    van den Hurk, B
    Jin, J M
    Kahan, D
    Lohmann, D
    Ma, X Y
    Mahanama, S
    Mocko, D
    Nasonova, O
    Niu, G Y
    Samuelsson, Patrick
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Schmakin, A B
    Takata, K
    Verseghy, D
    Viterbo, P
    Xia, Y L
    Xue, Y K
    Yang, Z L
    Simulation of high latitude hydrological processes in the Torne-Kalix basin: PILPS phase 2(e) - 2: Comparison of model results with observations2003Ingår i: Global and Planetary Change, ISSN 0921-8181, E-ISSN 1872-6364, Vol. 38, nr 1-2, s. 31-53Artikel i tidskrift (Refereegranskat)
  • 311. Nik, Vahid M.
    et al.
    Kalagasidis, Angela Sasic
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Assessment of hygrothermal performance and mould growth risk in ventilated attics in respect to possible climate changes in Sweden2012Ingår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 55, s. 96-109Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Most of the last 20 years in Sweden have been mild and wet compared to the 1961-1990 climate reference period. After a few relatively cold years in the mid-1980s, practically all years have been warmer than the preceding 30 years average. During the indicated period, an increase of moisture-related problems (mould growth) was observed in ventilated attics, a moisture sensitive building part. This work investigates hygrothermal performance of ventilated attics in respect to possible climate change. Hygrothermal simulations of attics were performed numerically in Matlab. Four attic constructions are investigated - a conventional attic and three alternative constructions suggested by practitioners. Simulations were done for the period of 1961-2100 using the weather data of RCA3 climate model. Effects of three different emissions scenarios are considered. Hygrothermal conditions in the attic are assessed using a mould growth model. Based on the results the highest risk of mould growth was found on the north roof of the attic in Gothenburg, Sweden. Results point to increment of the moisture problems in attics in future. Different emissions scenarios do not influence the risk of mould growth inside the attic due to compensating changes in different variables. Assessing the future performance of the four attics shows that the safe solution is to ventilate the attic mechanically, though this solution inevitably requires extra use of electrical energy for running the fan. Insulating roofs of the attic can decrease the condensation on roofs, but it cannot decrease the risk of mould growth considerably, on the wooden roof underlay. (C) 2012 Elsevier Ltd. All rights reserved.

  • 312. Nik, Vahid M.
    et al.
    Kalagasidis, Angela Sasic
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Statistical methods for assessing and analysing the building performance in respect to the future climate2012Ingår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 53, s. 107-118Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Global warming and its effects on climate are of great concern. Climate change can affect buildings in different ways. Increased structural loads from wind and water, changes in energy need and decreased moisture durability of materials are some examples of the consequences. Future climate conditions are simulated by global climate models (GCMs). Downscaling by regional climate models (RCMs) provides weather data with suitable temporal and spatial resolutions for direct use in building simulations. There are two major challenges when the future climate data are used in building simulations. The first is to handle and analyse the huge amount of data. The second challenge is to assess the uncertainties in building simulations as a consequence of uncertainties in the future climate data. In this paper two statistical methods, which have been adopted from climatology, are introduced. Applications of the methods are illustrated by looking into two uncertainty factors of the future climate; operating RCMs at different spatial resolutions and with boundary data from different GCMs. The Ferro hypothesis is introduced as a nonparametric method for comparing data at different spatial resolutions. The method is quick and subtle enough to make the comparison. The parametric method of decomposition of variabilities is described and its application in data assessment is shown by considering RCM data forced by different GCMs. The method enables to study data and its variations in different time scales. It provides a useful summary about data and its variations which makes the comparison between several data sets easier. (C) 2012 Elsevier Ltd. All rights reserved.

  • 313.
    Nikulin, Grigory
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Jones, Colin
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Giorgi, Filippo
    Asrar, Ghassem
    Buechner, Matthias
    Cerezo-Mota, Ruth
    Christensen, Ole Bossing
    Deque, Michel
    Fernandez, Jesus
    Haensler, Andreas
    van Meijgaard, Erik
    Samuelsson, Patrick
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Sylla, Mouhamadou Bamba
    Sushama, Laxmi
    Precipitation Climatology in an Ensemble of CORDEX-Africa Regional Climate Simulations2012Ingår i: Journal of Climate, ISSN 0894-8755, E-ISSN 1520-0442, Vol. 25, nr 18, s. 6057-6078Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An ensemble of regional climate simulations is analyzed to evaluate the ability of 10 regional climate models (RCMs) and their ensemble average to simulate precipitation over Africa. All RCMs use a similar domain and spatial resolution of similar to 50 km and are driven by the ECMWF Interim Re-Analysis (ERA-Interim) (1989-2008). They constitute the first set of simulations in the Coordinated Regional Downscaling Experiment in Africa (CORDEX-Africa) project. Simulated precipitation is evaluated at a range of time scales, including seasonal means, and annual and diurnal cycles, against a number of detailed observational datasets. All RCMs simulate the seasonal mean and annual cycle quite accurately, although individual models can exhibit significant biases in some subregions and seasons. The multimodel average generally outperforms any individual simulation, showing biases of similar magnitude to differences across a number of observational datasets. Moreover, many of the RCMs significantly improve the precipitation climate compared to that from their boundary condition dataset, that is, ERA-Interim. A common problem in the majority of the RCMs is that precipitation is triggered too early during the diurnal cycle, although a small subset of models does have a reasonable representation of the phase of the diurnal cycle. The systematic bias in the diurnal cycle is not improved when the ensemble mean is considered. Based on this performance analysis, it is assessed that the present set of RCMs can be used to provide useful information on climate projections over Africa.

  • 314.
    Nikulin, Grigory
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Evaluation of temperature extremes from an ensemble of transient RCM simulations driven by several AOGCMs2009Konferensbidrag (Övrigt vetenskapligt)
  • 315.
    Nikulin, Grigory
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Bärring, Lars
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Changes in daily temperature variability over Europe from an ensemble of RCM simulations driven by several AOGCMs2009Konferensbidrag (Övrigt vetenskapligt)
  • 316.
    Nikulin, Grigory
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Bärring, Lars
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Changes in daily temperature variability over Europe from an ensemble of regional climate simulations driven by several AOGCMs.2009Konferensbidrag (Övrigt vetenskapligt)
  • 317.
    Nikulin, Grigory
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Bärring, Lars
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Intraseasonal temperature variability over Europe in a future climate scenario2008Ingår i: Abstracts of the contributions of the EGU General Assembly 2008., 2008, Vol. 10, artikel-id EGU2008-A-09248Konferensbidrag (Övrigt vetenskapligt)
  • 318.
    Nikulin, Grigory
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Bärring, Lars
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Projected changes in daily temperature variability over Europe in an ensemble of RCM simulations2009Konferensbidrag (Övrigt vetenskapligt)
  • 319.
    Nikulin, Grigory
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Hansson, Ulf
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Jones, Colin
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Strandberg, Gustav
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Ullerstig, Anders
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Nordic weather extremes as simulated by the Rossby Centre Regional Climate Model: model evaluation and future projections2010Konferensbidrag (Övrigt vetenskapligt)
  • 320.
    Nikulin, Grigory
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Hansson, Ulf
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Strandberg, Gustav
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Ullerstig, Anders
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    European weather extremes as simulated by the Rossby Centre Regional Climate Model2010Ingår i: Geophysical Research Abstracts, 2010, Vol. 12, artikel-id EGU2010-4204Konferensbidrag (Refereegranskat)
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  • 321.
    Nikulin, Grigory
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Hansson, Ulf
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Strandberg, Gustav
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Ullerstig, Anders
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Evaluation and future projections of temperature, precipitation and wind extremes over Europe in an ensemble of regional climate simulations2011Ingår i: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 63, nr 1, s. 41-55Artikel i tidskrift (Refereegranskat)
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  • 322.
    Nikulin, Grigory
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Jones, Colin
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Uncertainties in the projected climate changes of wind extremes over the Baltic region2010Konferensbidrag (Övrigt vetenskapligt)
  • 323.
    Nikulin, Grigory
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Lennard, Chris
    Dosio, Alessandro
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Chen, Youmin
    Haensler, Andreas
    Kupiainen, Marco
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Laprise, Rene
    Mariotti, Laura
    Maule, Cathrine Fox
    van Meijgaard, Erik
    Panitz, Hans-Juergen
    Scinocca, John F.
    Somot, Samuel
    The effects of 1.5 and 2 degrees of global warming on Africa in the CORDEX ensemble2018Ingår i: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 13, nr 6, artikel-id 065003Artikel i tidskrift (Refereegranskat)
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  • 324.
    Nikulin, Grigory
    et al.
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Lott, F.
    On the time-scales of the downward propagation and of the tropospheric planetary wave response to the stratospheric circulation2010Ingår i: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 28, nr 2, s. 339-351Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three datasets (the NCEP-NCAR reanalysis, the ERA-40 reanalysis and the LMDz-GCM), are used to analyze the relationships between large-scale dynamics of the stratosphere and the tropospheric planetary waves during the Northern Hemisphere (NH) winter. First, a cross-spectral analysis clarifies the time scales at which downward propagation of stratospheric anomalies occurs in the low-frequency band (that is at periods longer than 50 days). At these periods the strength of the polar vortex, measured by the 20-hPa Northern Annular Mode (NAM) index and the wave activity flux, measured by the vertical component of the Eliassen-Palm flux (EPz) from both the troposphere and the stratosphere, are significantly related with each other and in lead-lag quadrature. While, in the low-frequency band of the downward propagation, the EPz anomalies of the opposite sign around NAM extremes drive the onset and decay of NAM events, we found that the EPz anomalies in the troposphere, are significantly larger after stratospheric vortex anomalies than at any time before. This marked difference in the troposphere is related to planetary waves with zonal wavenumbers 1-3, showing that there is a tropospheric planetary wave response to the earlier state of the stratosphere at low frequencies. We also find that this effect is due to anomalies in the EPz issued from the northern midlatitudes and polar regions.

  • 325. Nilsson, C.
    et al.
    Goyette, S.
    Bärring, Lars
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Relating forest damage data to the wind field from high-resolution RCM simulations: Case study of Anatol striking Sweden in December 19992007Ingår i: Global and Planetary Change, ISSN 0921-8181, E-ISSN 1872-6364, Vol. 57, nr 1-2, s. 161-176Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Forestry is of major economical importance in Europe, and recent devastating windstorms have pinpointed the vulnerability of this economic sector to windstorms. Forest damage is an important economic issue at a country level and may become even of larger concern under future conditions following global warming. An underlying question is to what extent the storm damage is due to changes in the wind climate compared to the effect of changes in forest management practices? In this paper, the first part of this rather complex problem is tackled. By using the Canadian Regional Climate Model, CRCM, including a physically based gust parameterisation scheme, NCEPNCAR reanalysis wind fields for the windstorm Anatol, on December 3-4, 1999, were downscaled, into a nested set-up, to 2 km resolution. The aim is to relate the simulated storm wind field to the observed distribution of storm damaged forests in Scania in southern Sweden, as a first methodological step towards analysing the effect of future windstorms in Swedish forests at the highest spatial resolution one can afford nowadays. Our results show that the CRCM produced realistic wind field simulations, compared to station observations, of the windstorm event in 1999. The simulated winds were underestimated at the coasts, but in congruence with inland observations. Most of the damaged forest stands were located on south-westerly (SW) slopes, which indicated a south-westerly wind during the wind throw process. This SW wind direction was evident in the early phase of the simulated storm, but then changed into a westerly flow, at an earlier stage than the true observations specified. Further, most damage occurred in the areas of simulated maximum wind speed greater than 30 m s. To conclude, the CRCM has proven to be a useful tool to realistically simulate a forest damaging storm event. Hence, the model could be used for further study cases, preferably driven by a GCM, in order to reveal a greater understanding about recent storms, which in turn helps us evaluate future climate change driven storm conditions. (c) 2006 Elsevier B.V All rights reserved.

  • 326. Ning, T.
    et al.
    Elgered, G.
    Willén, Ulrika
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Johansson, J. M.
    Evaluation of the atmospheric water vapor content in a regional climate model using ground-based GPS measurements2013Ingår i: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 118, nr 2, s. 329-339Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ground-based GPS measurements can provide independent data for the assessment of climate models. We use the atmospheric integrated water vapor (IWV) obtained from GPS measurements at 99 European sites to evaluate the regional Rossby Centre Atmospheric climate model (RCA) driven at the boundaries by the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data (ERA Interim). The GPS data were compared to the RCA simulation and the ERA Interim data. The comparison was first made using the monthly mean values. Averaged over the domain and the 14 years covered by the GPS data, IWV differences of about 0.47 kg/m(2) and 0.39 kg/m(2) are obtained for RCA-GPS and ECMWF-GPS, respectively. The RCA-GPS standard deviation is 0.98 kg/m(2) whereas it is 0.35 kg/m(2) for the ECMWF-GPS comparison. The IWV differences for RCA are positively correlated to the differences for ECMWF. However, this is not the case for two sites in Italy where a wet bias is seen for ECMWF, while a dry bias is seen for RCA, the latter being consistent with a cold temperature bias found for RCA in that region by other authors. Comparisons of the estimated diurnal cycle and the spatial structure function of the IWV were made between the GPS data and the RCA simulation. The RCA captures the geographical variation of the diurnal peak in the summer. Averaged over all sites, a peak at 17 local solar time is obtained from the GPS data while it appears later, at 18, in the RCA simulation. The spatial variation of the IWV obtained for an RCA run with a resolution of 11 km gives a better agreement with the GPS results than does the spatial variation from a 50 km resolution run. Citation: Ning, T., G. Elgered, U. Willen, and J. M. Johansson (2013), Evaluation of the atmospheric water vapor content in a regional climate model using ground-based GPS measurements, J. Geophys. Res. Atmos., 118, 329-339, doi: 10.1029/2012JD018053.

  • 327. Ning, T.
    et al.
    Haas, R.
    Elgered, G.
    Willen, Ulrika
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Multi-technique comparisons of 10 years of wet delay estimates on the west coast of Sweden2012Ingår i: Journal of Geodesy, ISSN 0949-7714, E-ISSN 1432-1394, Vol. 86, nr 7, s. 565-575Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    We present comparisons of 10-year-long time series of the atmospheric zenith wet delay (ZWD), estimated using the global positioning system (GPS), geodetic very long baseline interferometry (VLBI), a water vapour radiometer (WVR), radiosonde (RS) observations, and the reanalysis product of the European Centre for Medium-Range Weather Forecasts (ECMWF). To compare the data sets with each other, a Gaussian filter is applied. The results from 10 GPS-RS comparisons using sites in Sweden and Finland show that the full width at half maximum at which the standard deviation (SD) is a minimum increases with the distance between each pair. Comparisons between three co-located techniques (GPS, VLBI, and WVR) result in mean values of the ZWD differences at a level of a few millimetres and SD of less than 7 mm. The best agreement is seen in the GPS-VLBI comparison with a mean difference of -3.4 mm and an SD of 5.1 mm over the 10-year period. With respect to the ZWD derived from other techniques, a positive bias of up to similar to 7 mm is obtained for the ECMWF reanalysis product. Performing the comparisons on a monthly basis, we find that the SD including RS or ECMWF varies with the season, between 3 and 15 mm. The monthly SD between GPS and WVR does not have a seasonal signature and varies from 3 to 7 mm.

  • 328. Näslund, J-O
    et al.
    Wohlfarth, B
    Alexandersson, H
    Helmens, K
    Hättestrand, M
    Jansson, P
    Kleman, J
    Lundqvist, J
    Brandefelt, J
    Houmark-Nielsen, M
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Strandberg, Gustav
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Knudsen, K.L
    Krog Larsen, N
    Ukkonen, P
    Mangerud, J
    Fennoscandian paleo-environment and ice sheet dynamics during Marine Isotope Stage (MIS) 32007Rapport (Övrigt vetenskapligt)
  • 329. Ogawa, Fumiaki
    et al.
    Keenlyside, Noel
    Gao, Yongqi
    Koenigk, Torben
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Yang, Shuting
    Suo, Lingling
    Wang, Tao
    Gastineau, Guillaume
    Nakamura, Tetsu
    Cheung, Ho Nam
    Omrani, Nour-Eddine
    Ukita, Jinro
    Semenov, Vladimir
    Evaluating Impacts of Recent Arctic Sea Ice Loss on the Northern Hemisphere Winter Climate Change2018Ingår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 45, nr 7, s. 3255-3263Artikel i tidskrift (Refereegranskat)
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  • 330.
    Olsson, Jonas
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Borris, Matthias
    Donnelly, Chantal
    SMHI, Forskningsavdelningen, Hydrologi.
    Foster, Kean
    SMHI, Forskningsavdelningen, Hydrologi.
    Nikulin, Grigory
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Persson, Magnus
    SMHI.
    Perttu, Anna-Maria
    Uvo, Cintia B.
    Viklander, Maria
    Yang, Wei
    SMHI, Forskningsavdelningen, Hydrologi.
    Hydrological Climate Change Impact Assessment at Small and Large Scales: Key Messages from Recent Progress in Sweden2016Ingår i: CLIMATE, ISSN 2225-1154, Vol. 4, nr 3, artikel-id 39Artikel i tidskrift (Refereegranskat)
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  • 331.
    Olsson, Jonas
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Borris, Matthias
    Donnelly, Chantal
    SMHI, Forskningsavdelningen, Hydrologi.
    Foster, Kean
    SMHI, Forskningsavdelningen, Hydrologi.
    Nikulin, Grigory
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Persson, Magnus
    Perttu, Anna-Maria
    Uvo, Cintia B.
    Viklander, Maria
    Yang, Wei
    SMHI, Forskningsavdelningen, Hydrologi.
    Hydrological Climate Change Impact Assessment at Small and Large Scales: Recent Progress and Current Issues.2016Ingår i: Climate, ISSN 2225-1154, Vol. 4(3), nr 39Artikel i tidskrift (Refereegranskat)
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  • 332.
    Olsson, Jonas
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Berg, Peter
    SMHI, Forskningsavdelningen, Hydrologi.
    Eronn, Anna
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Simonsson, Lennart
    SMHI, Forskningsavdelningen, Hydrologi.
    Södling, Johan
    SMHI, Affärsverksamhet.
    Wern, Lennart
    SMHI, Samhälle och säkerhet.
    Yang, Wei
    SMHI, Forskningsavdelningen, Hydrologi.
    Extremregn i nuvarande och framtida klimat Analyser av observationer och framtidsscenarier2018Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Studien har främst omfattat analyser av extrem korttidsnederbörd i observationer från SMHIs nät av automatiska meteorologiska stationer. Även analyser av korttidsnederbörd från kommunala mätare, manuella meteorologiska stationer, väderradar och klimatmodeller har genomförts. De huvudsakliga slutsatserna från detta uppdrag kan sammanfattas enligt följande.

    • En regionalisering av extrem korttidsnederbörd (skyfall) i Sverige gav fyra regioner: sydvästra (SV), sydöstra (SÖ), mellersta (M) och norra (N) Sverige. Ytterligare indelning kan göras men i denna studie prioriterades att ha regioner av denna storleksordning för att få ett ordentligt underlag för regional statistik. Regionaliseringen gäller enbart korttidsnederbörd, upp till maximalt 12 tim varaktighet.
    • Den regionala statistiken uppvisar tämligen distinkta geografiska skillnader, med högst värden i region SV och lägst i region N. Det är inte förvånande att vårt avlånga land uppvisar regionala skillnader då varmare och fuktigare luftmassor förekommer mer i söder än i norr, och därmed ökar förutsättningarna för intensiv nederbörd. Den regionala statistiken överensstämmer överlag väl med motsvarande statistik i våra grannländer.
    • Under perioden 1996-2017 finns inga tydliga tidsmässiga tendenser vad gäller skyfallens storlek och frekvens i de olika regionerna, utan dessa ligger överlag på en konstant nivå. Inte heller extrem dygnsnederbörd sedan 1900 uppvisar några tydliga tendenser på regional nivå. På nationell nivå indikeras en svag ökning av dels landets högsta årliga nederbörd sedan 1881, dels förekomsten av stora, utbredda 2-dygnsregn sedan 1961.
    • Skyfallsstatistik baserad på nederbördsobservationer från väderradar som justerats mot interpolerade stationsdata (HIPRAD) överensstämmer väl med stationsbaserad statistik för korta varaktigheter (upp till 2 tim) i södra Sverige. För längre varaktigheter och i mellersta och norra Sverige överskattar HIPRAD regnvolymerna.
    • Analyser av de senaste klimatmodellerna (Euro-CORDEX) indikerar en underskattning av extrema regnvolymer för korta varaktigheter (1 tim) men överlag en realistisk beskrivning av observerad skyfallsstatistik. Den framtida ökningen av volymerna beräknas ligga mellan 10% och 40% beroende på tidshorisont och koncentration av växthusgaser, vilket överlag ligger nära tidigare bedömningar.

    Både för bedömningen av regionala skillnader och historiska klimateffekter är det av största vikt att bibehålla, eller ännu hellre utöka, observationerna av korttidsnederbörd i Sverige. Nederbördsmätning via alternativa tekniker bör kunna användas i allt högre utsträckning framöver för förbättrad kunskap och statistik. Väderradar är redan etablerat och den digitala utvecklingen öppnar även möjligheter till insamling av nederbördsdata och relaterad information via mobilmaster, uppkopplade privata väderstationer, sociala medier, etc. Denna utveckling måste bevakas, utvärderas och i största möjliga utsträckning utnyttjas.

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  • 333.
    Olsson, Jonas
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Graham, Phil
    SMHI, Affärsverksamhet.
    Rosberg, Jörgen
    SMHI, Forskningsavdelningen, Hydrologi.
    Hellström, Sara-Sofia
    SMHI, Forskningsavdelningen, Hydrologi.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Berndtsson, Ronny
    Lund University, Department of Water Resources Engineering, .
    Simulation of Runoff in the Baltic Sea Drainage Basin During the Past Millennium2007Konferensbidrag (Övrigt vetenskapligt)
  • 334.
    Olsson, Jonas
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Södling, Johan
    SMHI, Affärsverksamhet.
    Berg, Peter
    SMHI, Forskningsavdelningen, Hydrologi.
    Wern, Lennart
    SMHI, Samhälle och säkerhet.
    Eronn, Anna
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Short-duration rainfall extremes in Sweden: a regional analysis2019Ingår i: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 50, nr 3, s. 945-960Artikel i tidskrift (Refereegranskat)
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  • 335. Olusegun, Christiana Funmilola
    et al.
    Oguntunde, Philip G.
    Gbobaniyi, Bode
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre. SMHI, Affärsverksamhet.
    Simulating the Impacts of Tree, C3, and C4 Plant Functional Types on the Future Climate of West Africa2018Ingår i: Climate, ISSN 2053-7565, E-ISSN 2225-1154, Vol. 6, nr 2, artikel-id 35Artikel i tidskrift (Refereegranskat)
    Ladda ner fulltext (pdf)
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  • 336. Omstedt, Anders
    et al.
    Edman, Moa
    SMHI, Forskningsavdelningen, Oceanografi.
    Claremar, Bjorn
    Rutgersson, Anna
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Modelling the contributions to marine acidification from deposited SOx, NOx, and NHx in the Baltic Sea: Past and present situations2015Ingår i: Continental Shelf Research, ISSN 0278-4343, E-ISSN 1873-6955, Vol. 111, s. 234-249Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have examined the effects of historical atmospheric depositions of sulphate, nitrate, and ammonium from land and shipping on the acid-base balance in the Baltic Sea. The modelling considers the 1750-2014 period, when land and ship emissions changed greatly, with increasing carbon dioxide concentrations, SOx, NOx, and NHx emissions, and nutrient loads. The present results indicate that Baltic Sea acidification due to the atmospheric deposition of acids peaked around 1980, with a pH cumulative decrease of approximately 10(-2) in surface waters. This is one order of magnitude less than the cumulative acidification due to increased atmospheric CO2. The acidification contribution of shipping is one order of magnitude less than that of land emissions. However, the pH trend due to atmospheric acids has started to reverse due to reduced land emissions, though the effect of shipping is ongoing. The effect of strong atmospheric acids on Baltic Sea water depends on the region and period studied. The largest total alkalinity sink per surface area is in the south-western Baltic Sea where shipping is intense. Considering the entire Baltic Sea over the 2001-2010 period, the pH changes are approximately -3 x 10(-3) to -11 x 10(-3) and -4 x 10(-4) to -16 x 10(-4) pH units attributable to all emissions and ship emissions only, respectively. The corresponding changes in total alkalinity are approximately -10 to -30 mu mol kg(-1) and -1 to -4 mu mol kg(-1) attributable to all emissions and ship emissions only, respectively. (C) 2015 Elsevier Ltd. All rights reserved.

  • 337.
    Omstedt, Anders
    et al.
    SMHI, Forskningsavdelningen, Oceanografi.
    Rutgersson, Anna
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Closing the water and heat cycles of the Baltic Sea2000Ingår i: Meteorologische Zeitschrift, ISSN 0941-2948, E-ISSN 1610-1227, Vol. 9, nr 1, s. 59-66Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The objective of the present paper is to analyze the water and heat cycles of the Baltic Sea. The closure equations fur the water and heat cycles are formulated and the appropriate fluxes are calculated using the ocean model PROBE-Baltic forced by meteorological fields, river runoff and sea level data from the Kattegat. The time period considered is from November 1980 to November 1995. In the closing of the water cycle it is clear that river runoff, net precipitation (precipitation minus evaporation), in- and outflows through the Baltic Sea entrance area are the dominating flows. From the ocean model it is illustrated that the long-term water balance is consistent with the salinity in the Baltic Sea and that the net precipitation is positive during the studied period. For the closing of the heat cycle, the net heat loss to the atmosphere from the open water surface, as an annual moan, is in close balance with the solar radiation. The dominating fluxes in the net heat loss to the atmosphere are the sensible heat flux, the latent heat Aux and the net long wave radiation. The heat flux from water to ice also needs to be included in the modeling efforts. Heat flows associated with precipitation in the form of rain and snow can, as annual means, be neglected as well as the heat fluxes associated with river runoff, solar radiation through the ice and ice advecting out through the Baltic Sea entrance area. The total annual mean heat loss from the water body is in close balance with the annual change of heat storage in the water and the net heat exchange through the Baltic Sea entrance area is small. This illustrates that the Baltic Sea thermodynamically responds as a closed ocean basin.

  • 338. Orsolini, Yvan J.
    et al.
    Karpechko, Alexey Yu.
    Nikulin, Grigory
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Variability of the Northern Hemisphere polar stratospheric cloud potential: The role of North Pacific disturbances2009Ingår i: Quarterly Journal of the Royal Meteorological Society, ISSN 0035-9009, E-ISSN 1477-870X, Vol. 135, nr 641, s. 1020-1029Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The potential of the Arctic stratosphere to sustain the formation of Polar Stratospheric Clouds (PSCs) is a key factor in determining the amount of ozone destroyed each winter, and is often measured as a 'PSC volume'. The latter quantity has been shown to closely follow a near-linear compact relationship with winter-averaged column ozone loss, and displays a high variability from monthly to decadal time-scales. We examine the connection between meteorological conditions in the troposphere and the variability of lower polar stratospheric temperatures over the last four decades, and specifically, conditions leading to a high PSC volume. In addition to the well-established connection between the North Atlantic Oscillation (NAO) and the polar vortex, we demonstrate the large influence of precursory disturbances over the North Pacific and the Far East, the region of maximum climatological upward wave activity flux. Namely, very high monthly PSC volume (in the top 12%) predominantly follows the development of positive tropospheric height anomalies over the Far East, which lead to a weakening of the background planetary wave trough, and lessened upward wave activity flux into the stratosphere. Precursory anomalies over the Far East are reminiscent of East Asian monsoon amplification episodes. Copyright (C) 2009 Royal Meteorological Society

  • 339. Osima, Sarah
    et al.
    Indasi, Victor S.
    Zaroug, Modathir
    Endris, Hussen Seid
    Gudoshava, Masilin
    Misiani, Herbert O.
    Nimusiima, Alex
    Anyah, Richard O.
    Otieno, George
    Ogwang, Bob A.
    Jain, Suman
    Kondowe, Alfred L.
    Mwangi, Emmah
    Lennard, Chris
    Nikulin, Grigory
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Dosio, Alessandro
    Projected climate over the Greater Horn of Africa under 1.5 degrees C and 2 degrees C global warming2018Ingår i: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 13, nr 6, artikel-id 065004Artikel i tidskrift (Refereegranskat)
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  • 340. Ott, Irena
    et al.
    Duethmann, Doris
    Liebert, Joachim
    Berg, Peter
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Feldmann, Hendrik
    Ihringer, Juergen
    Kunstmann, Harald
    Merz, Bruno
    Schaedler, Gerd
    Wagner, Sven
    High-Resolution Climate Change Impact Analysis on Medium-Sized River Catchments in Germany: An Ensemble Assessment2013Ingår i: Journal of Hydrometeorology, ISSN 1525-755X, E-ISSN 1525-7541, Vol. 14, nr 4, s. 1175-1193Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The impact of climate change on three small- to medium-sized river catchments (Ammer, Mulde, and Ruhr) in Germany is investigated for the near future (2021-50) following the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario. A 10-member ensemble of hydrological model (HM) simulations, based on two high-resolution regional climate models (RCMs) driven by two global climate models (GCMs), with three realizations of ECHAM5 (E5) and one realization of the Canadian Centre for Climate Modelling and Analysis version 3 (CCCma3; C3) is established. All GCM simulations are downscaled by the RCM Community Land Model (CLM), and one realization of E5 is downscaled also with the RCM Weather Research and Forecasting Model (WRF). This concerted 7-km, high-resolution RCM ensemble provides a sound basis for runoff simulations of small catchments and is currently unique for Germany. The hydrology for each catchment is simulated in an overlapping scheme, with two of the three HMs used in the project. The resulting ensemble hence contains for each chain link (GCM-realization-RCM-HM) at least two members and allows the investigation of qualitative and limited quantitative indications of the existence and uncertainty range of the change signal. The ensemble spread in the climate change signal is large and varies with catchment and season, and the results show that most of the uncertainty of the change signal arises from the natural variability in winter and from the RCMs in summer.

  • 341. Ou, Tinghai
    et al.
    Chen, Deliang
    Chen, Xingchao
    Lin, Changgui
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Yang, Kun
    Lai, Hui-Wen
    Zhang, Fuqing
    Simulation of summer precipitation diurnal cycles over the Tibetan Plateau at the gray-zone grid spacing for cumulus parameterization2020Ingår i: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894Artikel i tidskrift (Refereegranskat)
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  • 342. Palmer, T N
    et al.
    Räisänen, Jouni
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Quantifying the risk of extreme seasonal precipitation events in a changing climate2002Ingår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 415, nr 6871, s. 512-514Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Increasing concentrations of atmospheric carbon dioxide will almost certainly lead to changes in global mean climate(1). But because-by definition-extreme events are rare, it is significantly more difficult to quantify the risk of extremes. Ensemble-based probabilistic predictions(2), as used in short- and medium-term forecasts of weather and climate, are more useful than deterministic forecasts using a 'best guess' scenario to address this sort of problem(3,4). Here we present a probabilistic analysis of 19 global climate model simulations with a generic binary decision model. We estimate that the probability of total boreal winter precipitation exceeding two standard deviations above normal will increase by a factor of five over parts of the UK over the next 100 years. We find similar increases in probability for the Asian monsoon region in boreal summer, with implications for flooding in Bangladesh. Further practical applications of our techniques would be helped by the use of larger ensembles (for a more complete sampling of model uncertainty) and a wider range of scenarios at a resolution adequate to analyse average-size river basins.

  • 343. Paprotny, D.
    et al.
    Morales-Napoles, O.
    Vousdoukas, M. I.
    Jonkman, S. N.
    Nikulin, Grigory
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Accuracy of pan-European coastal flood mapping2019Ingår i: Journal of Flood Risk Management, ISSN 1753-318X, E-ISSN 1753-318X, Vol. 12, nr 2, artikel-id UNSP e12459Artikel i tidskrift (Refereegranskat)
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  • 344. Paquin, Jean-Philippe
    et al.
    Doescher, Ralf
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Sushama, Laxmi
    Koenigk, Torben
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Causes and consequences of mid-21st-century rapid ice loss events simulated by the Rossby centre regional atmosphere-ocean model2013Ingår i: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 65, artikel-id 19110Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent observations and modelling studies suggest that the Arctic climate is undergoing important transition. One manifestation of this change is seen in the rapid sea-ice cover decrease as experienced in 2007 and 2012. Although most numerical climate models cannot adequately reproduce the recent changes, some models produce similar Rapid Ice Loss Events (RILEs) during the mid-21st-century. This study presents an analysis of four specific RILEs clustered around 2040 in three transient climate projections performed with the coupled Rossby Centre regional Atmosphere-Ocean model (RCAO). The analysis shows that long-term thinning causes increased vulnerability of the Arctic Ocean sea-ice cover. In the Atlantic sector, pre-conditioning (thinning of sea ice) combined with anomalous atmospheric and oceanic heat transport causes large ice loss, while in the Pacific sector of the Arctic Ocean sea-ice albedo feedback appears important, particularly along the retreating sea-ice margin. Although maximum sea-ice loss occurs in the autumn, response in surface air temperature occurs in early winter, caused by strong increase in ocean-atmosphere surface energy fluxes, mainly the turbulent fluxes. Synchronicity of the events around 2040 in the projections is caused by a strong large-scale atmospheric circulation anomaly at the Atlantic lateral boundary of the regional model. The limited impact on land is caused by vertical propagation of the surface heat anomaly rather than horizontal, caused by the absence of low-level temperature inversion over the ocean.

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  • 345. Paquin-Ricard, Danahe
    et al.
    Jones, Colin
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Vaillancourt, Paul A.
    Using ARM Observations to Evaluate Cloud and Clear-Sky Radiation Processes as Simulated by the Canadian Regional Climate Model GEM2010Ingår i: Monthly Weather Review, ISSN 0027-0644, E-ISSN 1520-0493, Vol. 138, nr 3, s. 818-838Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The total downwelling shortwave (SWID) and longwave (LWD) radiation and its components are assessed for the limited-area version of the Global Environmental Multiscale Model (GEM-LAM) against Atmospheric Radiation Measurements (ARM) at two sites: the southern Great Plains (SGP) and the North Slope of Alaska (NSA) for the 1998-2005 period. The model and observed SWD and LWD are evaluated as a function of the cloud fraction (CF), that is, for overcast and clear-sky conditions separately, to isolate and analyze different interactions between radiation and 1) atmospheric aerosols and water vapor and 2) cloud liquid water. Through analysis of the mean diurnal cycle and normalized frequency distributions of surface radiation fluxes, the primary radiation error in GEM-LAM is seen to be an excess in SWD in the middle of the day. The SWD bias results from a combination of underestimated CF and clouds, when present, possessing a too-high solar transmissivity, which is particularly the case for optically thin clouds. Concurrent with the SWD bias, a near-surface warm bias develops in GEM-LAM, particularly at the SGP site in the summer. The ultimate cause of this warm bias is difficult to uniquely determine because of the range of complex interactions between the surface, atmospheric, and radiation processes that are involved. Possible feedback loops influencing this warm bias are discussed. The near-surface warm bias is the primary cause of an excess clear-sky LWD. This excess is partially balanced with respect to the all-sky LWD by an underestimated CF, which causes a negative bias in simulated all-sky emissivity. It is shown that there is a strong interaction between all the components influencing the simulated surface radiation fluxes with frequent error compensation, emphasizing the need to evaluate the individual radiation components at high time frequency.

  • 346.
    Persson, Christer
    et al.
    SMHI, Forskningsavdelningen, Luftmiljö.
    Ullerstig, Anders
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Model calculations of dispersion of lindane over Europe: Pilot study with comparisons to easurements around the Baltic Sea and the Kattegat1996Rapport (Övrigt vetenskapligt)
    Abstract [en]

    A pilot project is presented, where the dispersion model MATCH is tested for studies of dispersion and deposition of lindane (y-HCH) over Europe. Comparisons between rough model calculations and long-term measurements at stations around the Baltic Sea indicate a positive correlation both for concentration in air and for wet deposition, but the model results are a factor of 3-10 larger than the measurements. The MATCH model simulations seem to agree better with observations from the Swedish West-coast and North Sea areas. Since the model calculations in this pilot project are performed in a very simplified way we cannot exclude that uncertainties in our calculations can cause the detected differences. However, we think that also emission data, especially for Sweden and Finland, and the respresentativity of measurements should be investigated further in a future study.

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  • 347.
    Persson, Christer
    et al.
    SMHI, Forskningsavdelningen, Luftmiljö.
    Ullerstig, Anders
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Regional luftmiljöanalys för Västmanlands län baserad på MATCH modell-beräkningar och mätdata: Analys av 1994 års data1997Rapport (Övrigt vetenskapligt)
  • 348.
    Persson, Christer
    et al.
    SMHI, Forskningsavdelningen, Luftmiljö.
    Ullerstig, Anders
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Robertson, Lennart
    SMHI, Forskningsavdelningen, Luftmiljö.
    Kindbom, Karin
    IVL Swedish Environmental Research Institute.
    Sjöberg, Karin
    IVL Swedish Environmental Research Institute.
    The Swedish Precipitation Chemistry Network: Studies in network design usting the MATCH modelling system and statistical methods1996Rapport (Övrigt vetenskapligt)
    Abstract [en]

    In this study the Swedish Precipitation Chemistry Network has been examined thoroughly, including investigations into the representativeness of stations as well as into possibilities of time trend analysis. A suggestion of a new optimized network design is given.

    Using the MATCH modelling system, which has been developed as a tool for air pollution assessment studies, it has been possible to evaluate different hypothetical precipitation chemistry networks over Sweden. There is a clear indication from the different model experiments, focused on sulphur and nitrogen, that a proposed future reduction of the number of Swedish precipitation chemistry stations by about one third only has a small effect on the obtained annual and monthly wet deposition pattern over Sweden. Long-term changes in wet deposition can still be followed using this less dense station network. Comparisons with independent measurements indicate that errors in the MATCH system estirnates for sulphur and nitrogen are of the same size as for parallel measurements as long as the MATCH system has a sufficient number of high quality precipitation chernistry stations available for the region.

    A study of former results on wet deposition, using multivariate analysis, has clearly indicated that the base-cation deposition exhibits larger local variations than is the case for sulphur and nitrogen. Modelling of base-cation deposition is however not included in this study. The suggested reduction of the precipitation network is thus characterized by some caution, partly due to the base-cation deposition not being thoroughly investigated. Care has been taken not to diminish future possibilities in mapping base-cation deposition over Sweden.

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  • 349.
    Persson, Gunn
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Islossning i Torneälven2012Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Islossningen i Torneälven startar vid Haparanda-Tornio och sker sedan 2-5 dagar senare i Övertorneå- Pello. Därefter lossar isen vartefter uppströms. I Haparanda skedde islossningen i medeltal 3 maj och i Torneträsk 1 juni under perioden 2000-2009. I Torneträsk liksom för Haparanda sker islossningen ca 11 dagar tidigare idag jämfört med för 100 år sedan.Torneälven är känd för sina dramatiska islossningar på våren, som ibland leder till översvämningsproblem, huvudsakligen orsakade av isproppar. Efter de svåra islossningarna 1984-86 startade ett finsk-svenskt samarbetsprojekt kring isproblemen i Torneälven. Projektet slutredovisades 1989 och är refererad i denna rapport kompletterad med händelser de senaste 20 åren. Projektet förordade en rad olika åtgärder för att minska problemen med skador vid översvämningar i form av prognoser och varningar, tekniska åtgärder och riskzon-kartering. Få av de tekniska åtgärderna har realiserats. Flödes-prognoser och -varningar för Torneälven ingår idag i den reguljära verksamheten för SMHI och SYKE (Statens miljöförvaltning i Finland). Varje år görs också islossningsprognoser för Haparanda-Tornio.Inom Interreg IVA-projektet ”Detaljerad översvämningskartering i nedre delen av Torneälven”, 2009-2012, har ett av huvudmålen varit att producera översvämningskartor till stöd för lokal planering och lokala beslut men också som hjälp vid akuta översvämningsrisker. Kartorna ska användas för den riskzonkartering som utförs av MSB (Myndigheten för samhällsskydd och beredskap) inom EU:s över-svämningsdirektiv. Inom Interreg-projektet har SYKE utvecklat en modell för isuppbyggnad och islossning. SYKE testar nu ett sanno-likhetssystem för islossning och isproppar på några platser i älven.I Torneälven finns flera potentiella ställen för isproppar och de upp-träder i varierande grad på många olika ställen olika år. Ett särskilt problem är isproppar vid mynningen som kan drabba det område i regionen där flest skyddsvärda objekt finns, nämligen huvudorterna Haparanda och Tornio. För området finns planer på att muddra en farled vid mynningen och med isbrytare öppna den varje vår innan islossningen, för att förhindra isproppar vid mynningen. Projektet saknar dock tillräcklig finansiering i dagsläget.Att övervaka islossningsförloppet med hjälp av satellitbilder skulle kunna vara en framtida utvecklingsmöjlighet för att skapa ett förvarningssystem. Det förutsätter god tillgång till högupplösta och snabbt tillgängliga satellitbilder, vilket inte är fallet idag. För att vara operativt verksamt behövs även lokala aktörer med kapacitet att snabbt ta emot information och agera. Det finns projekt (ex. i Kanada) där övervakningssystem med satellitbilder testas, men inget operativt verksamt system tycks ännu finnas i världen.Den viktigaste åtgärden för att undvika stora problem vid översvämningar är att inte ha skyddsvärda objekt på översvämnings-hotade områden. Enkelt att förstå men ändå svårt att åstadkomma.

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  • 350.
    Persson, Gunn
    et al.
    SMHI, Affärsverksamhet.
    Bärring, Lars
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Kjellström, Erik
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Strandberg, Gustav
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Rummukainen, Markku
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Climate indices for vulnerability assessments2007Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Behovet av information om klimatets förändring och dess effekter på olika regioner och sektorer ökar stadigt. För att belysa frågeställningar runt klimatets utveckling, dess påverkan och behov av anpassning behövs projektioner av framtidens klimat. Den generella kunskapen om klimat baseras oftast på erfarenhet av tidigare klimat, väderobservationer, prognoser och återanalyser av historiska data. För att hantera framtidens föränderliga klimat behöver vi utveckla metoder för att förfina användningen av information från klimatmodeller. Klimatindex, formulerade med avnämarperspektiv i fokus och beräknade utifrån data från klimatmodeller, är ett sätt att kommunicera den komplexa frågan om effekter av klimatets framtida utveckling. Klimatindex kan vara välkänd information som summerad nederbörd eller medeltemperaturer men kan också beskriva mer komplexa relationer och då innefatta till exempel tröskelvärden eller exponeringstid för olika förhållanden. I denna rapport beskrivs ett omfattande material av klimatindex baserade på beräkningar med två regionala klimatmodeller utifrån olika utsläppsscenarier och globala klimatmodeller. Materialet har legat till grund för arbetet inom den svenska Klimat- och sårbarhetsutredningen (M2005:03), men har även framtagits i samarbete med andra avnämargrupper. De flesta klimatmodeller och klimatscenarier som ligger till grund för indexberäkningarna har tidigare dokumenterats i andra rapporter men ges här en övergripande beskrivning. Till rapporten bifogas en DVD med det omfattande kartmaterial som illustrerar indexberäkningarna och tillhörande information. Materialet finns även tillgängligt på www.smhi.se.

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