Change search
Refine search result
293031323334 1551 - 1600 of 1685
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1551. Tjernstrom, M.
    et al.
    Birch, C. E.
    Brooks, I. M.
    Shupe, M. D.
    Persson, P. O. G.
    Sedlar, Joseph
    SMHI, Research Department, Atmospheric remote sensing.
    Mauritsen, T.
    Leck, C.
    Paatero, J.
    Szczodrak, M.
    Wheeler, C. R.
    Meteorological conditions in the central Arctic summer during the Arctic Summer Cloud Ocean Study (ASCOS)2012In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 12, no 15, p. 6863-6889Article in journal (Refereed)
    Abstract [en]

    Understanding the rapidly changing climate in the Arctic is limited by a lack of understanding of underlying strong feedback mechanisms that are specific to the Arctic. Progress in this field can only be obtained by process-level observations; this is the motivation for intensive ice-breaker-based campaigns such as the Arctic Summer Cloud-Ocean Study (ASCOS), described here. However, detailed field observations also have to be put in the context of the larger-scale meteorology, and short field campaigns have to be analysed within the context of the underlying climate state and temporal anomalies from this. To aid in the analysis of other parameters or processes observed during this campaign, this paper provides an overview of the synoptic-scale meteorology and its climatic anomaly during the ASCOS field deployment. It also provides a statistical analysis of key features during the campaign, such as key meteorological variables, the vertical structure of the lower troposphere and clouds, and energy fluxes at the surface. In order to assess the representativity of the ASCOS results, we also compare these features to similar observations obtained during three earlier summer experiments in the Arctic Ocean: the AOE-96, SHEBA and AOE-2001 expeditions. We find that these expeditions share many key features of the summertime lower troposphere. Taking ASCOS and the previous expeditions together, a common picture emerges with a large amount of low-level cloud in a well-mixed shallow boundary layer, capped by a weak to moderately strong inversion where moisture, and sometimes also cloud top, penetrate into the lower parts of the inversion. Much of the boundary-layer mixing is due to cloud-top cooling and subsequent buoyant overturning of the cloud. The cloud layer may, or may not, be connected with surface processes depending on the depths of the cloud and surface-based boundary layers and on the relative strengths of surface-shear and cloud-generated turbulence. The latter also implies a connection between the cloud layer and the free troposphere through entrainment at cloud top.

  • 1552. Tjernstrom, M.
    et al.
    Leck, C.
    Birch, C. E.
    Bottenheim, J. W.
    Brooks, B. J.
    Brooks, I. M.
    Backlin, L.
    Chang, Y. -W
    de Leeuw, G.
    Di Liberto, L.
    de la Rosa, S.
    Granath, E.
    Graus, M.
    Hansel, A.
    Heintzenberg, J.
    Held, A.
    Hind, A.
    Johnston, P.
    Knulst, J.
    Martin, M.
    Matrai, P. A.
    Mauritsen, T.
    Mueller, M.
    Norris, S. J.
    Orellana, M. V.
    Orsini, D. A.
    Paatero, J.
    Persson, P. O. G.
    Gao, Q.
    Rauschenberg, C.
    Ristovski, Z.
    Sedlar, Joseph
    SMHI, Research Department, Atmospheric remote sensing.
    Shupe, M. D.
    Sierau, B.
    Sirevaag, A.
    Sjogren, S.
    Stetzer, O.
    Swietlicki, E.
    Szczodrak, M.
    Vaattovaara, P.
    Wahlberg, N.
    Westberg, M.
    Wheeler, C. R.
    The Arctic Summer Cloud Ocean Study (ASCOS): overview and experimental design2014In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 14, no 6, p. 2823-2869Article in journal (Refereed)
    Abstract [en]

    The climate in the Arctic is changing faster than anywhere else on earth. Poorly understood feedback processes relating to Arctic clouds and aerosol-cloud interactions contribute to a poor understanding of the present changes in the Arctic climate system, and also to a large spread in projections of future climate in the Arctic. The problem is exacerbated by the paucity of research-quality observations in the central Arctic. Improved formulations in climate models require such observations, which can only come from measurements in situ in this difficult-to-reach region with logistically demanding environmental conditions. The Arctic Summer Cloud Ocean Study (ASCOS) was the most extensive central Arctic Ocean expedition with an atmospheric focus during the International Polar Year (IPY) 2007-2008. ASCOS focused on the study of the formation and life cycle of low-level Arctic clouds. ASCOS departed from Longyearbyen on Svalbard on 2 August and returned on 9 September 2008. In transit into and out of the pack ice, four short research stations were undertaken in the Fram Strait: two in open water and two in the marginal ice zone. After traversing the pack ice northward, an ice camp was set up on 12 August at 87 degrees 21' N, 01 degrees 29' W and remained in operation through 1 September, drifting with the ice. During this time, extensive measurements were taken of atmospheric gas and particle chemistry and physics, mesoscale and boundary-layer meteorology, marine biology and chemistry, and upper ocean physics. ASCOS provides a unique interdisciplinary data set for development and testing of new hypotheses on cloud processes, their interactions with the sea ice and ocean and associated physical, chemical, and biological processes and interactions. For example, the first-ever quantitative observation of bubbles in Arctic leads, combined with the unique discovery of marine organic material, polymer gels with an origin in the ocean, inside cloud droplets suggests the possibility of primary marine organically derived cloud condensation nuclei in Arctic stratocumulus clouds. Direct observations of surface fluxes of aerosols could, however, not explain observed variability in aerosol concentrations, and the balance between local and remote aerosols sources remains open. Lack of cloud condensation nuclei (CCN) was at times a controlling factor in low-level cloud formation, and hence for the impact of clouds on the surface energy budget. ASCOS provided detailed measurements of the surface energy balance from late summer melt into the initial autumn freeze-up, and documented the effects of clouds and storms on the surface energy balance during this transition. In addition to such process-level studies, the unique, independent ASCOS data set can and is being used for validation of satellite retrievals, operational models, and reanalysis data sets.

  • 1553. Tjernstrom, M
    et al.
    Zagar, M
    Svensson, G
    Cassano, J J
    Pfeifer, S
    Rinke, A
    Wyser, Klaus
    SMHI, Research Department, Climate research - Rossby Centre.
    Dethloff, K
    Jones, Colin
    SMHI, Research Department, Climate research - Rossby Centre.
    Semmler, T
    Shaw, M
    Modelling the arctic boundary layer: An evaluation of six arcmip regional-scale models using data from the Sheba project2005In: Boundary-layer Meteorology, ISSN 0006-8314, E-ISSN 1573-1472, Vol. 117, no 2, p. 337-381Article in journal (Refereed)
    Abstract [en]

    A primary climate change signal in the central Arctic is the melting of sea ice. This is dependent on the interplay between the atmosphere and the sea ice, which is critically dependent on the exchange of momentum, heat and moisture at the surface. In assessing the realism of climate change scenarios it is vital to know the quality by which these exchanges are modelled in climate simulations. Six state-of-the-art regional-climate models are run for one year in the western Arctic, on a common domain that encompasses the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment ice-drift track. Surface variables, surface fluxes and the vertical structure of the lower troposphere are evaluated using data from the SHEBA experiment. All the models are driven by the same lateral boundary conditions, sea-ice fraction and sea and sea-ice surface temperatures. Surface pressure, near-surface air temperature, specific humidity and wind speed agree well with observations, with a falling degree of accuracy in that order. Wind speeds have systematic biases in some models, by as much as a few metres per second. The surface radiation fluxes are also surprisingly accurate, given the complexity of the problem. The turbulent momentum flux is acceptable, on average, in most models, but the turbulent heat fluxes are, however, mostly unreliable. Their correlation with observed fluxes is, in principle, insignificant, and they accumulate over a year to values an order of magnitude larger than observed. Typical instantaneous errors are easily of the same order of magnitude as the observed net atmospheric heat flux. In the light of the sensitivity of the atmosphere-ice interaction to errors in these fluxes, the ice-melt in climate change scenarios must be viewed with considerable caution.

  • 1554. Tjernström, M
    et al.
    Rummukainen, Markku
    SMHI, Research Department, Climate research - Rossby Centre.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    Rodhe, J.
    SMHI.
    Persson, Gunn
    SMHI, Professional Services.
    Klimatmodellering och klimatscenarier ur SWECLIMs perspektiv2003Report (Other academic)
  • 1555. Tjernström, M.
    et al.
    Zagar, M.
    Svensson, G.
    Dethloff, K.
    Rinke, A.
    Cassano, J.
    Pfeifer, S.
    Semmler, T.
    Jones, Colin
    SMHI, Research Department, Climate research - Rossby Centre.
    Wyser, Klaus
    SMHI, Research Department, Climate research - Rossby Centre.
    The Arctic boundary-layer in six different RCM compared to SHEBA observations (ARCMIP).2005In: Extended abstracts of a WMO/WCRP-sponsored Regional-Scale Climate Modelling Workshop [Elektronisk resurs] : high-resolution climate modelling : assessment, added value and applications, Lund, Sweden, 29 March-2 April 2004 / [ed] Lars Bärring & René Laprise, Lund: Department of Physical Geography & Ecosystems Analysis, Lund University , 2005, p. 44-45Conference paper (Other academic)
  • 1556. Tobin, Isabelle
    et al.
    Jerez, Sonia
    Vautard, Robert
    Thais, Francoise
    van Meijgaard, Erik
    Prein, Andreas
    Deque, Michel
    Kotlarski, Sven
    Maule, Cathrine Fox
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Noel, Thomas
    Teichmann, Claas
    Climate change impacts on the power generation potential of a European mid-century wind farms scenario2016In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 11, no 3, article id 034013Article in journal (Refereed)
    Abstract [en]

    Wind energy resource is subject to changes in climate. To investigate the impacts of climate change on future European wind power generation potential, we analyze a multi-model ensemble of the most recent EURO-CORDEX regional climate simulations at the 12 km grid resolution. We developed a mid-century wind power plant scenario to focus the impact assessment on relevant locations for future wind power industry. We found that, under two greenhouse gas concentration scenarios, changes in the annual energy yield of the future European wind farms fleet as a whole will remain within +/- 5% across the 21st century. At country to local scales, wind farm yields will undergo changes up to 15% in magnitude, according to the large majority of models, but smaller than 5% in magnitude for most regions and models. The southern fleets such as the Iberian and Italian fleets are likely to be the most affected. With regard to variability, changes are essentially small or poorly significant from subdaily to interannual time scales.

  • 1557. Toledano, C.
    et al.
    Cachorro, V. E.
    Gausa, M.
    Stebel, K.
    Aaltonen, V.
    Berjon, A.
    Ortiz de Galisteo, J. P.
    de Frutos, A. M.
    Bennouna, Y.
    Blindheim, S.
    Myhre, C. L.
    Zibordi, G.
    Wehrli, C.
    Kratzer, S.
    Håkansson, Bertil
    SMHI, Research Department, Oceanography.
    Carlund, Thomas
    SMHI, Core Services.
    de Leeuw, G.
    Herber, A.
    Torres, B.
    Overview of sun photometer measurements of aerosol properties in Scandinavia and Svalbard2012In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 52, p. 18-28Article in journal (Refereed)
    Abstract [en]

    An overview on the data of columnar aerosol properties measured in Northern Europe is provided. Apart from the necessary data gathered in the Arctic, the knowledge of the aerosol loading in nearby areas (e.g. sub-Arctic) is of maximum interest to achieve a correct analysis of the Arctic aerosols and transport patterns. This work evaluates data from operational sites with sun photometer measurements belonging either to national or international networks (AERONET, GAW-PFR) and programs conducted in Scandinavia and Svalbard. We enumerate a list of sites, measurement type and periods together with observed aerosol properties. An evaluation and analysis of aerosol data was carried out with a review of previous results as well. Aerosol optical depth (AOD) and Angstrom exponent (AE) are the current parameters with sufficient long-term records for a first evaluation of aerosol properties. AOD (500 nm) ranges from 0.08 to 0.10 in Arctic and sub-Arctic sites (Ny-Alesund: 0.09; Andenes: 0.10; Sodankyla: 0.08), and it is somewhat higher in more populated areas in Southern Scandinavia (AOD about 0.10-0.12 at 500 nm). On the Norwegian coast, aerosols show larger mean size (AE = 1.2 at Andenes) than in Finland, with continental climate (AE = 1.5 at Sodankyla). Columnar particle size distributions and related parameters derived from inversion of sun/sky radiances were also investigated. This work makes special emphasis in the joint and collaborative effort of the various groups from different countries involved in this study. Part of the measurements presented here were involved in the IPY projects Polar-AOD and POLARCAT. (C) 2011 Elsevier Ltd. All rights reserved.

  • 1558. Tonderski, K S
    et al.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Modeling the impact of potential wetlands on phosphorus retention in a Swedish catchment2005In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 34, no 7, p. 544-551Article in journal (Refereed)
    Abstract [en]

    In southern Sweden, wetlands are constructed to remove nitrogen (N) in agricultural catchments. The possible effects of such wetlands on riverine phosphorus (P) were also estimated using input-output data from three well-monitored wetlands. This was done to formulate a simple model for removal of P that is dependent on inflow characteristics. Next, the N- and P-reducing effects of wetlands were modeled on a catchment scale (1900 km 2) using the HBV-NP model and various assumptions about the wetland area and location. All three wetlands functioned as sinks for total P (tot-P) and for total suspended solids (TSS) with a removal of 10% to 31% and 28% to 50%, respectively. Mean P-removal rates of 17-49 kg ha(-1) yr(-1) were well simulated with the model. Catchment scale simulations indicated that wetlands were more efficient (in percentage of load) as traps for P than for N and that this may motivate the construction of wetlands for P removal far upstream from the catchment outlet.

  • 1559. Tonderski, Karin
    et al.
    Andersson, Lotta
    SMHI, Research Department, Hydrology.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    St Cyr, Rasmus
    Schoenberg, Ronny
    Taubald, Heinrich
    Assessing the use of delta O-18 in phosphate as a tracer for catchment phosphorus sources2017In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 607, p. 1-10Article in journal (Refereed)
  • 1560. Tourigny, Etienne
    et al.
    Jones, Colin
    SMHI, Research Department, Climate research - Rossby Centre.
    An analysis of regional climate model performance over the tropical Americas. Part I: simulating seasonal variability of precipitation associated with ENSO forcing2009In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 61, no 3, p. 323-342Article in journal (Refereed)
    Abstract [en]

    Sea surface temperature (SST) anomalies associated with El Nino/Southern Oscillation (ENSO) constitute a major source of predictability in the tropics. We evaluate the ability of a regional climate model (the Rossby Centre Atmospheric Model; RCA) to downscale SST and large-scale atmospheric anomalies associated with ENSO. RCA is configured over the tropical east Pacific and tropical Americas and runs for the period 1979-2005, using European Centre for Medium-Range Weather Forecasts (ECMWF) lateral and surface boundary conditions. We study the ability of RCA to represent regional patterns of precipitation, with respect to both the climatology and interannual variability associated with ENSO. The latter is achieved by grouping the simulations into El Nino and La Nina composites and studying the delayed response of precipitation to SST forcing in four regions of Central and South America. In this paper, we concentrate on seasonal mean timescales. We find that RCA accurately simulates the main features of the precipitation climatology over the four regions and also reproduces the majority of the documented regional responses to ENSO forcing. Furthermore, the model captures the variability in precipitation anomalies between different ENSO events. The model exhibits a wet bias over the northern Amazon and slightly overestimates the magnitude of ENSO anomalies over Central America.

  • 1561. Tourigny, Etienne
    et al.
    Jones, Colin
    SMHI, Research Department, Climate research - Rossby Centre.
    An analysis of regional climate model performance over the tropical Americas. Part II: simulating subseasonal variability of precipitation associated with ENSO forcing2009In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 61, no 3, p. 343-356Article in journal (Refereed)
    Abstract [en]

    The El Nino/Southern Oscillation (ENSO) constitutes a major source of potential predictability in the tropics. The majority of past seasonal prediction studies have concentrated on precipitation anomalies at the seasonal mean timescale. However, fields such as agriculture and water resource management require higher time frequency forecasts of precipitation variability. Regional climate models (RCMs), with their increased resolution, may offer one means of improving general circulation model forecasts of higher time frequency precipitation variability. Part I of this study evaluated the ability of the Rossby Centre regional atmospheric model (RCA), forced by analysed boundary conditions, to simulate seasonal mean precipitation anomalies over the tropical Americas associated with ENSO variability. In this paper the same integrations are analysed, with the focus now on precipitation anomalies at subseasonal (pentad) timescales. RCA simulates the climatological annual cycle of pentad-mean precipitation intensity quite accurately. The timing of the rainy season (onset, demise and length) is well simulated, with biases generally of less than 2 weeks. Changes in the timing and duration of the rainy season, associated with ENSO forcing, are also well captured. Finally, pentad-mean rainfall intensity distributions are simulated quite accurately, as are shifts in these distributions associated with ENSO forcing.

  • 1562.
    Trolez, Matthieu
    et al.
    SMHI.
    Karlsson, Karl-Göran
    SMHI, Research Department, Atmospheric remote sensing.
    Johnston, Sheldon
    SMHI, Research Department, Climate research - Rossby Centre.
    Albert, Peter
    SMHI.
    The impact of varying NWP background information on CM-SAF cloud products: Visiting Scientist Report Climate Monitoring SAF (CM-SAF)2008Report (Other academic)
    Abstract [en]

    The purpose of this study was to quantify the impact of using ancillary data from Numerical Weather Prediction (NWP) models in the derivation of cloud parameters from satellite data in the Climate Monitoring Satellite Application Facility (CM-SAF) project. In particular, the sensitivity to the NWP-analysed surface temperature parameter was studied.A one-year dataset of satellite images over the Scandinavian region from the Advanced Very High Resolution Radiometer (AVHRR) on the polar orbiting NOAA satellites was studied. Cloud products were generated by use of the Polar Platform System (PPS) cloud software and the sensitivity to perturbations of the NWP-analysed surface temperature was investigated. In addition, a study on the importance of the chosen NWP model was also included. Results based on three different NWP models (ECMWF, HIRLAM and GME) were analysed.It was concluded that the NWP model influence on the results appears to be small. An interchange of NWP model analysis input data to the PPS cloud processing method did only lead to marginal changes of the resulting CM-SAF cloud products. Thus, the current CM-SAF cloud algorithmsproduce robust results that are not heavily dependent on NWP model background information. Nevertheless, the study demonstrated a natural high sensitivity to the NWP-analysed surface skin temperature. This parameter is crucial for the a priori determination of the thresholds used for the infrared cloud tests of the PPS method. It was shown that a perturbation of the surface skin temperature of one K generally resulted in a change of cloud cover of about 0.5-1 % in absolute cloud amount units. However, if perturbations were in the range 5-10 K the change in cloud cover increased to values between 1 to 2 % per degree, especially for positive perturbations. Important here is that a positive surface temperature perturbation always leads to an increase in the resulting cloud amounts and vice versa.

  • 1563.
    Trolez, Matthieu
    et al.
    SMHI.
    Tetzlaff, Anke
    SMHI, Research Department, Atmospheric remote sensing.
    Karlsson, Karl-Göran
    SMHI, Research Department, Atmospheric remote sensing.
    CM-SAF Validating the Cloud Top Height product using LIDAR data2005Report (Other academic)
  • 1564. Tuomi, Laura
    et al.
    Kanarik, Hedi
    Bjorkqvist, Jan-Victor
    Marjamaa, Riikka
    Vainio, Jouni
    Hordoir, Robinson
    SMHI, Research Department, Oceanography.
    Höglund, Anders
    SMHI, Research Department, Oceanography.
    Kahma, Kimmo K.
    Impact of Ice Data Quality and Treatment on Wave Hindcast Statistics in Seasonally Ice-Covered Seas2019In: Frontiers in Earth Science, ISSN 2296-6463, Vol. 7, article id UNSP 166Article in journal (Refereed)
  • 1565. Turner, David R.
    et al.
    Edman, Moa
    SMHI, Research Department, Oceanography.
    Gallego-Urrea, Julian Alberto
    Claremar, Bjorn
    Hassellov, Ida-Maja
    Omstedt, Anders
    Rutgersson, Anna
    The potential future contribution of shipping to acidification of the Baltic Sea2018In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 47, no 3, p. 368-378Article in journal (Refereed)
  • 1566. Tyson, P D
    et al.
    Garstang, M
    Swap, R
    Kållberg, Per
    SMHI, Research Department, Meteorology.
    Edwards, M
    An air transport climatology for subtropical southern Africa1996In: International Journal of Climatology, ISSN 0899-8418, E-ISSN 1097-0088, Vol. 16, no 3, p. 265-291Article in journal (Refereed)
    Abstract [en]

    An air transport climatology is derived for subtropical southern Africa (Africa south of 15 degrees S) by classifying daily synoptic situations into predominant circulation types. The annual variation of these provides the basis for determining month-by-month transport. Percentage zonal transport in easterly and westerly directions, levels of transport, and times of transit are derived from forward trajectory analyses using European Centre for Medium-range Weather Forecasts (ECMWF) data for a 7-year period. It is shown that semi-permanent subtropical continental anticyclones, transient mid-latitude ridging anticyclones and midlatitude westerly disturbances produce major transport into the south-western Indian Ocean in the Natal plume. Only quasistationary tropical easterly waves result in appreciable transport into the tropical South Atlantic Ocean in the Angolan plume. Total transport is a function of circulation type and frequency, as well as plume dimensions. Transport in continental highs follows an annual cycle reaching peak values in excess of 70 per cent in winter. That in easterly waves also exhibits an annual cycle, but one peaking in summer, when up to 55 per cent transport may occur in north-western regions. Transport in ridging highs and westerly perturbations is much less and occurs throughout the year, with a slight tendency to peak in spring. Recirculation of air is shown to be considerable when anticyclonic conditions prevail. Monthly, seasonal, and annual mass fluxes over and out of southern Africa are determined from transport fields, frequency of occurrence of circulation types and from measurements of aerosol concentrations. An annual mass flux of aerosols some 134 Mtons is generated over the subcontinent. About 60 Mtons year(-1) are deposited, and approximately 29 Mtons year(-1) are exported westward over the Atlantic Ocean and 45 Mtons year(-1) eastward over the Indian Ocean. Twenty-six million tons of the 74 Mtons of aerosols exported annually to the adjacent oceans on each coast are a product of recirculation. Deposition within 10 degrees latitude of the coast is nearly 10 times greater on the east than on the west coast.

  • 1567. Vali, Germo
    et al.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Elken, Jueri
    Simulated halocline variability in the Baltic Sea and its impact on hypoxia during 1961-20072013In: JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, ISSN 2169-9275, Vol. 118, no 12, p. 6982-7000Article in journal (Refereed)
    Abstract [en]

    Salinity and halocline depth variations in the Baltic Sea during 1961-2007 are studied using a three-dimensional ocean circulation model. Significant interannual and interdecadal variations in the halocline depth are found, together with distinct periods characterized either by shallow (1970-1975) or deep halocline (1990-1995). The model simulation indicates that the mean top layer salinity in the Baltic Sea is mainly controlled by the accumulated river runoff, while the mean below halocline salinity in the Baltic proper (which comprises Bornholm and Gotland basins) is more dependent on the low-pass filtered zonal wind stress, with cutoff period of 4 years, henceforth called the mean zonal wind stress. The halocline depth and stratification strength in the Baltic Sea are significantly affected by the mean zonal wind stress, while the impact of runoff is smaller. The ventilation of the halocline from bottom layers is stronger during the shallow and from surface layers during the deep halocline period. Due to changes in ventilation variations in halocline depth systematically affect bottom oxygen concentrations on seasonal and decadal, but not on interannual time scales. For instance, a deeper halocline reduces hypoxic (oxygen concentration in bottom water below 2 mL/L) and anoxic (anoxic conditions in bottom water) areas and increases the bottom oxygen concentrations in the Gulf of Finland but decreases them in the deeper parts of the Baltic proper. Model results suggest that due to undersampling during 1961-2007 mean hypoxic and anoxic areas calculated from observed profiles are underestimated by 41% and 43%, respectively.

  • 1568. Van den Dool, H. M.
    et al.
    Peng, Peitao
    Johansson, Åke
    SMHI, Research Department, Meteorology.
    Chelliah, Muthuvel
    Shabbar, Amir
    Saha, Suranjana
    Seasonal-to-decadal predictability and prediction of North American climate - The Atlantic influence2006In: Journal of Climate, ISSN 0894-8755, E-ISSN 1520-0442, Vol. 19, no 23, p. 6005-6024Article in journal (Refereed)
    Abstract [en]

    The question of the impact of the Atlantic on North American (NA) seasonal prediction skill and predictability is examined. Basic material is collected from the literature, a review of seasonal forecast procedures in Canada and the United States, and some fresh calculations using the NCEP-NCAR reanalysis data. The general impression is one of low predictability (due to the Atlantic) for seasonal mean surface temperature and precipitation over NA. Predictability may be slightly better in the Caribbean and the (sub) tropical Americas, even for precipitation. The NAO is widely seen as an agent making the Atlantic influence felt in NA. While the NAO is well established in most months, its prediction skill is limited. Year-round evidence for an equatorially displaced version of the NAO (named ED_NAO) carrying a good fraction of the variance is also found. In general the predictability from the Pacific is thought to dominate over that from the Atlantic sector, which explains the minimal number of reported Atmospheric Model Intercomparison Project (AMIP) runs that explore Atlantic-only impacts. Caveats are noted as to the question of the influence of a single predictor in a nonlinear environment with many predictors. Skill of a new one-tier global coupled atmosphere-ocean model system at NCEP is reviewed; limited skill is found in midlatitudes and there is modest predictability to look forward to. There are several signs of enthusiasm in the community about using "trends" (low-frequency variations): (a) seasonal forecast tools include persistence of last 10 years' averaged anomaly (relative to the official 30-yr climatology), (b) hurricane forecasts are based largely on recognizing a global multidecadal mode (which is similar to an Atlantic trend mode in SST), and (c) two recent papers, one empirical and one modeling, giving equal roles to the (North) Pacific and Atlantic in "explaining" variations in drought frequency over NA on a 20 yr or longer time scale during the twentieth century.

  • 1569. van den Dool, H M
    et al.
    Saha, S
    Johansson, Åke
    SMHI, Research Department, Meteorology.
    Empirical orthogonal teleconnections2000In: Journal of Climate, ISSN 0894-8755, E-ISSN 1520-0442, Vol. 13, no 8, p. 1421-1435Article in journal (Refereed)
    Abstract [en]

    A new variant is proposed for calculating functions empirically and orthogonally from a given space-time dataset. The method is rooted in multiple linear regression and yields solutions that are orthogonal in one direction, either space or time. In normal setup, one searches for that point in space, the base point (predictor). which, by linear regression, explains the most of the variance at all other points (predictands) combined. The first spatial pattern is the regression coefficient between the base point and all other points, and the first time series is taken to be the time series of the raw data at the base point. The original dataset is next reduced; that is, what has been accounted for by the first mode is subtracted out. The procedure is repeated exactly as before for the second, third, etc., modes. These new functions are named empirical orthogonal teleconnections (EOTs). This is to emphasize the similarity of EOT to both teleconnections and (biorthogonal) empirical orthogonal functions (EOFs). One has to choose the orthogonal direction for EOT. In the above description of the normal space-time setup, picking successive base points in space, the time series are orthogonal. One can reverse the role of time and space-in this case one picks base points in time, and the spatial maps will be orthogonal. If the dataset contains biorthogonal modes, the EOTs are the same for both setups and are equal to the EOFs. When applied to four commonly used datasets, the procedure was found to work well in terms of explained variance (EV) and in terms of extracting familiar patterns. In all examples the EV for EOTs was only slightly less than the optimum obtained by EOF. A numerical recipe was given to calculate EOF, starting from EOT as an initial guess. When subjected to cross validation the EOTs seem to fare well in terms of explained variance on independent data las good as EOF). The EOT procedure can be implemented very easily and has, for some (but not all) applications, advantages over EOFs. These novelties, advantages, and applications include the following. 1) One can pick certain modes (or base point) first-the order of the EOTs is free, and there is a near-infinite set of EOTs. 2) EOTs are linked to specific points in space or moments in time. 3) When linked to Row at specific moments in time, the EOT modes have undeniable physical reality. 4) When linked to flow at specific moments in time, EOTs appear to be building blocks for empirical forecast methods because one can naturally access the time derivative. 5) When linked to specific points in space, one has a rational basis to define strategically chosen points such that an analysis of the whole domain would benefit maximally from observations at these locations.

  • 1570. Van den Hurk, B
    et al.
    Hirschi, M
    Schar, C
    Lenderink, G
    Van Meijgaard, E
    Van Ulden, A
    Rockel, B
    Hagemann, S
    Graham, Phil
    SMHI, Research Department, Climate research - Rossby Centre.
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Jones, R
    Soil control on runoff response to climate change in regional climate model simulations2005In: Journal of Climate, ISSN 0894-8755, E-ISSN 1520-0442, Vol. 18, no 17, p. 3536-3551Article in journal (Refereed)
    Abstract [en]

    Simulations with seven regional climate models driven by a common control climate simulation of a GCM carried out for Europe in the context of the (European Union) EU-funded Prediction of Regional scenarios and Uncertainties for Defining European Climate change risks and Effects (PRUDENCE) project were analyzed with respect to land surface hydrology in the Rhine basin. In particular, the annual cycle of the terrestrial water storage was compared to analyses based on the 40-yr ECMWF Re-Analysis (ERA-40) atmospheric convergence and observed Rhine discharge data. In addition, an analysis was made of the partitioning of convergence anomalies over anomalies in runoff and storage. This analysis revealed that most models underestimate the size of the water storage and consequently overestimated the response of runoff to anomalies in net convergence. The partitioning of these anomalies over runoff and storage was indicative for the response of the simulated runoff to a projected climate change consistent with the greenhouse gas A2 Synthesis Report on Emission Scenarios (SRES). In particular, the annual cycle of runoff is affected largely by the terrestrial storage reservoir. Larger storage capacity leads to smaller changes in both wintertime and summertime monthly mean runoff. The sustained summertime evaporation resulting from larger storage reservoirs may have a noticeable impact on the summertime surface temperature projections.

  • 1571. van den Hurk, B J J M
    et al.
    Graham, Phil
    SMHI, Research Department, Climate research - Rossby Centre.
    Viterbo, P
    Comparison of land surface hydrology in regional climate simulations of the Baltic Sea catchment2002In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 255, no 1-4, p. 169-193Article in journal (Refereed)
    Abstract [en]

    Simulations with a regional climate model RACMO were carried out over the catchment area of the Baltic Sea for the growing season 1995. Two different surface schemes were included which in particular differed with respect to the parameterization of runoff. In the first scheme (taken from ECHAM4), runoff is a function of the subgrid distribution of the soil moisture saturation. In the second model (taken from ECMWF), runoff is a result of deep-water drainage. A large-scale hydrological model of the catchment, HBV-Baltic, was calibrated to river discharge data and forced with observed precipitation, yielding independent comparison material of runoff of the two RACMO simulations. The simulations showed that the temporal and spatial simulation of precipitation in the area is sensitive to the choice of the land surface scheme in RACMO. This supported the motivation of analysing the land surface hydrological budgets in a coupled mode. The comparison of RACMO with HBV-Baltic revealed that the frequency distribution of runoff in the ECMWF scheme shows very little runoff variability at high frequencies, while in ECHAM4 and HBV the snow melt and (liquid) precipitation are followed by fast responding runoff events. The seasonal cycle of soil water depletion and surface evaporation was evaluated by comparison of model scores with respect to relative humidity. Results suggest that the surface evaporation in the ECMWF scheme is too strong in late spring and early summer, giving rise to too much drying later in the season. (C) 2002 Elsevier Science B.V. All rights reserved.

  • 1572. van der Gon, H. A. C. Denier
    et al.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Fountoukis, C.
    Johansson, C.
    Pandis, S. N.
    Simpson, D.
    Visschedijk, A. J. H.
    Particulate emissions from residential wood combustion in Europe revised estimates and an evaluation2015In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, no 11, p. 6503-6519Article in journal (Refereed)
    Abstract [en]

    Currently residential wood combustion (RWC) is increasing in Europe because of rising fossil fuel prices but also due to climate change mitigation policies. However, especially in small-scale applications, RWC may cause high emissions of particulate matter (PM). Recently we have developed a new high-resolution (7 x 7 km) anthropogenic carbonaceous aerosol emission inventory for Europe. The inventory indicated that about half of the total PM2.5 emission in Europe is carbonaceous aerosol and identified RWC as the largest organic aerosol source in Europe. The inventory was partly based on national reported PM emissions. Use of this organic aerosol inventory as input for two chemical transport models (CTMs), PMCAMx and EMEP MSC-W, revealed major underestimations of organic aerosol in winter time, especially for regions dominated by RWC. Interestingly, this was not universal but appeared to differ by country. In the present study we constructed a revised bottom-up emission inventory for RWC accounting for the semivolatile components of the emissions. The revised RWC emissions are higher than those in the previous inventory by a factor of 2-3 but with substantial inter-country variation. The new emission inventory served as input for the CTMs and a substantially improved agreement between measured and predicted organic aerosol was found. The revised RWC inven-tory improves the model-calculated organic aerosol significantly. Comparisons to Scandinavian source apportionment studies also indicate substantial improvements in the modelled wood-burning component of organic aerosol. This suggests that primary organic aerosol emission inventories need to be revised to include the semivolatile organic aerosol that is formed almost instantaneously due to dilution and cooling of the flue gas or exhaust. Since RWC is a key source of fine PM in Europe, a major revision of the emission estimates as proposed here is likely to influence source-receptor matrices and modelled source apportionment. Since usage of biofuels in small combustion units is a globally significant source, the findings presented here are also relevant for regions outside of Europe.

  • 1573. van Lipzig, Nicole P. M.
    et al.
    Schroeder, Marc
    Crewell, Susanne
    Ament, Felix
    Chaboureau, Jean-Pierre
    Loehnert, Ulrich
    Matthias, Volker
    van Meijgaard, Erik
    Quante, Markus
    Willén, Ulrika
    SMHI, Research Department, Climate research - Rossby Centre.
    Yen, Wenchieh
    Model predicted low-level cloud parameters - Part I: Comparison with observations from the BALTEX Bridge Campaigns2006In: Atmospheric research, ISSN 0169-8095, E-ISSN 1873-2895, Vol. 82, no 1-2, p. 55-82Article in journal (Refereed)
    Abstract [en]

    The BALTEX Bridge Campaigns (BBC), which were held in the Netherlands in 2001 and 2003 around the Cabauw Experimental Site for Atmospheric Research (CESAR), have provided detailed information on clouds. This paper is an illustration of how these measurements can be used to investigate whether 'state-of-the-art' atmospheric models are capable of adequately representing clouds. Here, we focus on shallow low-level clouds with a substantial amount of liquid water. In situ, ground-based and satellite remote sensing measurements were compared with the output of three non-hydrostatic regional models (Lokal-Modell, LM.- M&so-NH: fifth-generation Mesoscale Model, MM5) and two hydrostatic regional climate models (Regional Atmospheric Climate Model version 2, RACMO2; Rossby Centre Atmospheric Model, RCA). For the two selected days, Meso-NH and MM5 reproduce the measured vertical extent of the shallow clouds, but the liquid water content of the clouds is generally overestimated. In LM and the climate models the inversion is too weak and located at a level too close to the surface resulting in an overestimation of the vertical extent of the clouds. A sensitivity integration with RACM02 shows that the correspondence between model output and measurements can be improved by a doubling of the vertical resolution; this induces an increase in the modelled inversion strenath and cloud top pressure. LM and Meso-NH underestimate the lifetime of clouds. A comparison between model output and cloud cover derived from the Moderate Resolution Imaging Spectrometer (MODIS) indicates that this deficiency is not due to advection of too small cloud systems,- it is rather due to an overestimation of the variability in the vertical velocity. All models overestimate the specific humidity near the surface and underestimate it at higher atmospheric levels, indicating that the models underestimate the mixing of moisture in the boundary layer. This deficiency is slightly reduced by inclusion of parameterised shallow convection in the non-hydrostatic models, which enhances the mixing of heat and moisture in the boundary layer. Consequently, the explicitly resolved updrafts weaken resulting in reduced condensation rates and lower liquid water path. The temporal variability of cloud occurrence is hardly affected by inclusion of parameterised shallow convection. (c) 2006 Elsevier B.V. All rights reserved.

  • 1574. van Loon, M.
    et al.
    Vautard, R.
    Schaap, M.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Bessagnet, B.
    Brandt, J.
    Builtjes, P. J. H.
    Christensen, J. H.
    Cuvelier, C.
    Graff, A.
    Jonson, J. E.
    Krol, M.
    Langner, J.
    Roberts, P.
    Rouil, L.
    Stern, R.
    Tarrason, L.
    Thunis, P.
    Vignati, E.
    White, L.
    Wind, P.
    Evaluation of long-term ozone simulations from seven regional air quality models and their ensemble2007In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 41, no 10, p. 2083-2097Article in journal (Refereed)
    Abstract [en]

    Long-term ozone simulations from seven regional air quality models, the Unified EMEP model, LOTOS-EUROS, CHIMERE, RCG, MATCH, DEHM and TM5, are intercompared and compared to ozone measurements within the framework of the EuroDelta experiment, designed to assess air quality improvement at the European scale in response to emission reduction scenarios for 2020. Modelled ozone concentrations for the year 2001 are evaluated. The models reproduce the main features of the ozone diurnal cycle, but generally overestimate daytime ozone, LOTOS-EUROS and RCG have a more pronounced diurnal cycle variation than observations, while the reverse occurs for TM5. CHIMERE has a large positive bias, which can be explained by a systematic bias in boundary conditions. The other models and the "ensemble model", whose concentrations are by definition averaged over all models, represent accurately the diurnal cycle. The ability of the models to simulate day-to-day daily ozone average or maxima variability is examined by means of percentiles, root mean square errors and correlations. In general, daily maxima are better simulated than daily averages, and summertime concentrations are better simulated than wintertime concentrations. Summertime correlations range between 0.5 and 0.7 for daily averages and 0.6 and 0.8 for daily maxima. Two health-related indicators are used, the number of days of exceedance of the 120 mu g m(-3) threshold for the daily maximal 8-h ozone concentration and the SOMO35. Both are well reproduced in terms of frequency, but the simultaneity of occurrence of exceedance days between observations and simulations is not well captured.

  • 1575. van Meijgaard, E
    et al.
    Andrae, Ulf
    SMHI, Research Department, Meteorology.
    Rockel, B
    Comparison of model predicted cloud parameters and surface radiative fluxes with observations on the 100 km scale2001In: Meteorology and atmospheric physics (Print), ISSN 0177-7971, E-ISSN 1436-5065, Vol. 77, no 1-4, p. 109-130Article in journal (Refereed)
    Abstract [en]

    Cloud parameters and surface radiative fluxes predicted by regional atmospheric models are directly compared with observations for a 10-day period in late summer 1995 characterized by predominantly large-scale synoptic conditions. Observations of total cloud cover and Vertical cloud structure are inferred from measurements with a groundbased network of Lidar ceilometers and IR-radiometers and from satellite observations on a 100 kilometer scale. Groundbased observations show that at altitudes below 3 km, implying liquid water clouds, there is a considerable portion of optically non-opaque clouds. Vertical distributions of cloud temperatures simultaneously inferred from the groundbased infrared radiometer network and from satellite can only be reconciled if the occurrence of optically thin cloud structures at mid- and high tropospheric levels is assumed to be frequent. Results of three regional atmospheric models, i.e. the GKSS-REMO, SMHI-HIRLAM. and KNMI-RACMO, are quantitatively compared with the observations. The main finding is that all models predict too much cloud amount at low altitude below 900 hPa, which is then compensated by an underestimation of cloud amount around 800 hPa. This is likely to be related with the finding that all models tend to underestimate the planetary boundary layer height. All models overpredict the high-level cloud amount albeit it is difficult to quantify to what extent due to the frequent presence of optically thin clouds. Whereas reasonably alike in cloud parameters, the models differ considerably in radiative fluxes. One model links a well matching incoming solar radiation to a radiatively transparent atmosphere over a too cool surface, another model underpredicts incoming solar radiation at the surface due to a too strong cloud feedback to radiation, the last model represents all surface radiative fluxes quite well on average: but underestimates the sensitivity of atmospheric transmissivity to cloud amount.

  • 1576. Van Pham, Trang
    et al.
    Brauch, Jennifer
    Dieterich, Christian
    SMHI, Research Department, Oceanography.
    Frueh, Barbara
    Ahrens, Bodo
    New coupled atmosphere-ocean-ice system COSMO-CLM/NEMO: assessing air temperature sensitivity over the North and Baltic Seas2014In: Oceanologia, ISSN 0078-3234, Vol. 56, no 2, p. 167-189Article in journal (Refereed)
    Abstract [en]

    This paper introduces a newly established coupled atmosphere-ocean-ice system with the regional climate model COSMO-CLM and the ocean-sea-ice model NEMO for the North and Baltic Seas. These two models are linked via the OASIS3 coupler. Experiments with the new coupled system and with the stand-alone COSMO-CLM model forced by ERA-Interim re-analysis data over the period from 1985 to 1994 for the CORDEX Europe domain are carried out. The evaluation results of the coupled system show 2-m temperature biases in the range from -2.5 to 3 K. Simulated 2-m temperatures are generally colder in the coupled than in the uncoupled system, and temperature differences vary by season and space. The coupled model shows an improvement compared with the stand-alone COSMO-CLM in terms of simulating 2-m temperature. The difference in 2-m temperature between the two experiments are explained as downwind cooling by the colder North and Baltic Seas in the coupled system.

  • 1577. van Pul, Addo
    et al.
    Hertel, Ole
    Geels, Camilla
    Dore, Anthony J.
    Massimo, Vieno
    van Jaarsveld, Hans A.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Schaap, Martijn
    Fagerli, Hilde
    Modelling of the Atmospheric Transport and Deposition of Ammonia at a National and Regional Scale2009In: in Atmospheric Ammonia - Detecting emission changes and environmental impacts., Springer, 2009, p. 301-356Chapter in book (Other academic)
  • 1578. van Pul, Addo
    et al.
    Reis, Stefan
    Dore, Tony
    Xuejun, Liu
    Hilde, Fagerli
    Geels, Camilla
    Hertel, Ole
    Kruijt Roy, Wichink
    Kryza, Maciej
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Vieno, Massimo
    Ron, Smith
    Eiko, Nemitz
    Modelling the National and Regional Transport and Deposition of Ammonia2009In: Atmospheric Ammonia - Detecting emission changes and environmental impacts., Springer, 2009, p. 409-421Chapter in book (Other academic)
  • 1579. van Vliet, Michelle T. H.
    et al.
    Donnelly, Chantal
    SMHI, Research Department, Hydrology.
    Strombäck, Lena
    SMHI, Research Department, Hydrology.
    Capell, Réne
    SMHI, Research Department, Hydrology.
    Ludwig, Fulco
    European scale climate information services for water use sectors2015In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 528, p. 503-513Article in journal (Refereed)
    Abstract [en]

    This study demonstrates a climate information service for pan-European water use sectors that are vulnerable to climate change induced hydrological changes, including risk and safety (disaster preparedness), agriculture, energy (hydropower and cooling water use for thermoelectric power) and environment (water quality). To study the climate change impacts we used two different hydrological models forced with an ensemble of bias-corrected general circulation model (GCM) output for both the lowest (2.6) and highest (8.5) representative concentration pathways (RCP). Selected indicators of water related vulnerability for each sector were then calculated from the hydrological model results. Our results show a distinct north-south divide in terms of climate change impacts; in the south the water availability will reduce while in the north water availability will increase. Across different climate models precipitation and streamflow increase in northern Europe and decrease in southern Europe, but the latitude at which this change occurs varies depending on the GCM. Hydrological extremes are increasing over large parts of Europe. The agricultural sector will be affected by reduced water availability (in the south) and increased drought. Both streamflow and soil moistures droughts are projected to increase in most parts of Europe except in northern Scandinavia and the Alps. The energy sector will be affected by lower hydropower potential in most European countries and reduced cooling water availability due to higher water temperatures and reduced summer river flows. Our results show that in particular in the Mediterranean the pressures are high because of increasing drought which will have large impacts on both the agriculture and energy sectors. In France and Italy this is combined with increased flood hazards. Our results show important impacts of climate change on European water use sectors indicating a clear need for adaptation. (C) 2015 Published by Elsevier B.V.

  • 1580. Vanniere, Benoit
    et al.
    Demory, Marie-Estelle
    Vidale, Pier Luigi
    Schiemann, Reinhard
    Roberts, Malcolm J.
    Roberts, Christopher D.
    Matsueda, Mio
    Terray, Laurent
    Koenigk, Torben
    SMHI, Research Department, Climate research - Rossby Centre.
    Senan, Retish
    Multi-model evaluation of the sensitivity of the global energy budget and hydrological cycle to resolution2019In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 52, no 11, p. 6817-6846Article in journal (Refereed)
  • 1581. Vautard, R.
    et al.
    Schaap, M.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Bessagnet, B.
    Brandt, J.
    Builtjes, P. J. H.
    Christensen, J. H.
    Cuvelier, C.
    Foltescu, Valentin
    SMHI.
    Graff, A.
    Kerschbaumer, A.
    Krol, M.
    Roberts, P.
    Rouil, L.
    Stern, R.
    Tarrason, L.
    Thunis, P.
    Vignati, E.
    Wind, P.
    Skill and uncertainty of a regional air quality model ensemble2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 31, p. 4822-4832Article in journal (Refereed)
    Abstract [en]

    Recently several regional air quality projects were carried out to support the negotiation under the Clean Air For Europe (CAFE) programme by predicting the impact of emission control policies with an ensemble of models. Within these projects, CITYDELTA and EURODELTA, the fate of air quality at the scale of European cities or that of the European continent was studied using several models. In this article we focus on the results of EURODELTA. The predictive skill of the ensemble of models is described for ozone, nitrogen dioxide and secondary inorganic compounds, and the uncertainty in air quality modelling is examined through the model ensemble spread of concentrations. For ozone daily maxima the ensemble spread origin differs from one region to another. In the neighbourbood of cities or in mountainous areas the spread of predicted values does not span the range of observed data, due to poorly resolved emissions or complex-terrain meteorology. By contrast in Atlantic and North Sea coastal areas the spread of predicted values is found to be larger than the observations. This is attributed to large differences in the boundary conditions used in the different models. For NO2 daily averages the ensemble spread is generally too small compared with observations. This is because models miss highest values occurring in stagnant meteorology in stable boundary layers near cities. For secondary particulate matter compounds the simulated concentration spread is more balanced, observations falling nearly equiprobably within the ensemble, and the spread originates both from meteorology and aerosol chemistry and thermodynamics. (C) 2008 Published by Elsevier Ltd.

  • 1582. Vautard, R.
    et al.
    Van Loon, M.
    Schaap, M.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Bessagnet, B.
    Brandt, J.
    Builtjes, P. J. H.
    Christensen, J. H.
    Cuvelier, C.
    Graff, A.
    Jonson, J. E.
    Krol, M.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Roberts, P.
    Rouil, L.
    Stern, R.
    Tarrason, L.
    Thunis, P.
    Vignati, E.
    White, L.
    Wind, P.
    Is regional air quality model diversity representative of uncertainty for ozone simulation?2006In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 33, no 24, article id L24818Article in journal (Refereed)
    Abstract [en]

    We examine whether seven state-of-the-art European regional air quality models provide daily ensembles of predicted ozone maxima that encompass observations. Using tools borrowed from the evaluation of ensemble weather forecasting, we analyze statistics of simulated ensembles of ozone daily maxima over an entire summer season. Although the model ensemble overestimates ozone, the distribution of simulated concentrations is representative of the uncertainty. The spread of simulations is due to random fluctuations resulting from differences in model formulations and input data, but also to the spread between individual model systematic biases. The ensemble average skill increases as the spread decreases. The skill of the ensemble in giving probabilistic predictions of threshold exceedances is also demonstrated. These results allow for optimism about the ability of this ensemble to simulate the uncertainty of the impact of emission control scenarios.

  • 1583. Vautard, Robert
    et al.
    Gobiet, Andreas
    Jacob, Daniela
    Belda, Michal
    Colette, Augustin
    Deque, Michel
    Fernandez, Jesus
    Garcia-Diez, Markel
    Goergen, Klaus
    Guettler, Ivan
    Halenka, Tomas
    Karacostas, Theodore
    Katragkou, Eleni
    Keuler, Klaus
    Kotlarski, Sven
    Mayer, Stephanie
    van Meijgaard, Erik
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Patarcic, Mirta
    Scinocca, John
    Sobolowski, Stefan
    Suklitsch, Martin
    Teichmann, Claas
    Warrach-Sagi, Kirsten
    Wulfmeyer, Volker
    Yiou, Pascal
    The simulation of European heat waves from an ensemble of regional climate models within the EURO-CORDEX project2013In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 41, no 9-10, p. 2555-2575Article in journal (Refereed)
    Abstract [en]

    The ability of a large ensemble of regional climate models to accurately simulate heat waves at the regional scale of Europe was evaluated. Within the EURO-CORDEX project, several state-of-the art models, including non-hydrostatic meso-scale models, were run for an extended time period (20 years) at high resolution (12 km), over a large domain allowing for the first time the simultaneous representation of atmospheric phenomena over a large range of spatial scales. Eight models were run in this configuration, and thirteen models were run at a classical resolution of 50 km. The models were driven with the same boundary conditions, the ERA-Interim re-analysis, and except for one simulation, no observations were assimilated in the inner domain. Results, which are compared with daily temperature and precipitation observations (ECA&D and E-OBS data sets) show that, even forced by the same re-analysis, the ensemble exhibits a large spread. A preliminary analysis of the sources of spread, using in particular simulations of the same model with different parameterizations, shows that the simulation of hot temperature is primarily sensitive to the convection and the microphysics schemes, which affect incoming energy and the Bowen ratio. Further, most models exhibit an overestimation of summertime temperature extremes in Mediterranean regions and an underestimation over Scandinavia. Even after bias removal, the simulated heat wave events were found to be too persistent, but a higher resolution reduced this deficiency. The amplitude of events as well as the variability beyond the 90th percentile threshold were found to be too strong in almost all simulations and increasing resolution did not generally improve this deficiency. Resolution increase was also shown to induce large-scale 90th percentile warming or cooling for some models, with beneficial or detrimental effects on the overall biases. Even though full causality cannot be established on the basis of this evaluation work, the drivers of such regional differences were shown to be linked to changes in precipitation due to resolution changes, affecting the energy partitioning. Finally, the inter-annual sequence of hot summers over central/southern Europe was found to be fairly well simulated in most experiments despite an overestimation of the number of hot days and of the variability. The accurate simulation of inter-annual variability for a few models is independent of the model bias. This indicates that internal variability of high summer temperatures should not play a major role in controlling inter-annual variability. Despite some improvements, especially along coastlines, the analyses conducted here did not allow us to generally conclude that a higher resolution is clearly beneficial for a correct representation of heat waves by regional climate models. Even though local-scale feedbacks should be better represented at high resolution, combinations of parameterizations have to be improved or adapted accordingly.

  • 1584. Vautard, Robert
    et al.
    Gobiet, Andreas
    Sobolowski, Stefan
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Stegehuis, Annemiek
    Watkiss, Paul
    Mendlik, Thomas
    Landgren, Oskar
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Teichmann, Claas
    Jacob, Daniela
    The European climate under a 2 degrees C global warming2014In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 9, no 3, article id 034006Article in journal (Refereed)
    Abstract [en]

    A global warming of 2 degrees C relative to pre-industrial climate has been considered as a threshold which society should endeavor to remain below, in order to limit the dangerous effects of anthropogenic climate change. The possible changes in regional climate under this target level of global warming have so far not been investigated in detail. Using an ensemble of 15 regional climate simulations downscaling six transient global climate simulations, we identify the respective time periods corresponding to 2 degrees C global warming, describe the range of projected changes for the European climate for this level of global warming, and investigate the uncertainty across the multi-model ensemble. Robust changes in mean and extreme temperature, precipitation, winds and surface energy budgets are found based on the ensemble of simulations. The results indicate that most of Europe will experience higher warming than the global average. They also reveal strong distributional patterns across Europe, which will be important in subsequent impact assessments and adaptation responses in different countries and regions. For instance, a North-South (West-East) warming gradient is found for summer (winter) along with a general increase in heavy precipitation and summer extreme temperatures. Tying the ensemble analysis to time periods with a prescribed global temperature change rather than fixed time periods allows for the identification of more robust regional patterns of temperature changes due to removal of some of the uncertainty related to the global models' climate sensitivity.

  • 1585. Veihelmann, B
    et al.
    Nousiainen, T
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    van der Zande, W J
    Light scattering by small feldspar particles simulated using the Gaussian random sphere geometry2006In: Journal of Quantitative Spectroscopy and Radiative Transfer, ISSN 0022-4073, E-ISSN 1879-1352, Vol. 100, no 1-3, p. 393-405Article in journal (Refereed)
    Abstract [en]

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

  • 1586. Venohr, M
    et al.
    Donohue, I
    Fogelberg, S
    SMHI.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Irvine, K
    Behrendt, H
    Nitrogen retention in a river system and the effects of river morphology and lakes2005In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 51, no 3-4, p. 19-29Article in journal (Refereed)
    Abstract [en]

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

  • 1587.
    Venäläinen, Ari
    et al.
    Finnish Meteorological Institute, Finland.
    Saku, Seppo
    Finnish Meteorological Institute, Finland.
    Jylhä, Kirsti
    Finnish Meteorological Institute, Finland.
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Bärring, Lars
    SMHI, Research Department, Climate research - Rossby Centre.
    Climate extremes and safety of nuclear power plants: Extreme temperatures and enthalpy in Finland and Sweden in a changing climate.2009Report (Other academic)
  • 1588. Vercauteren, Nikki
    et al.
    Boyko, Vyacheslav
    Kaiser, Amandine
    Belusic, Danijel
    SMHI, Research Department, Climate research - Rossby Centre.
    Statistical Investigation of Flow Structures in Different Regimes of the Stable Boundary Layer2019In: Boundary-layer Meteorology, ISSN 0006-8314, E-ISSN 1573-1472, Vol. 173, no 2, p. 143-164Article in journal (Refereed)
    Abstract [en]

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

  • 1589. Verhoeven, J T A
    et al.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Yin, C Q
    Hefting, M M
    Regional and global concerns over wetlands and water quality2006In: Trends in Ecology & Evolution, ISSN 0169-5347, E-ISSN 1872-8383, Vol. 21, no 2, p. 96-103Article, review/survey (Refereed)
    Abstract [en]

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

  • 1590. Verma, Siddhartha
    et al.
    Bartosova, Alena
    SMHI, Research Department, Hydrology.
    Markus, Momcilo
    Cooke, Richard
    Um, Myoung-Jin
    Park, Daeryong
    Quantifying the Role of Large Floods in Riverine Nutrient Loadings Using Linear Regression and Analysis of Covariance2018In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 10, no 8, article id 2876Article in journal (Refereed)
  • 1591. Verma, Siddhartha
    et al.
    Markus, Momcilo
    Bartosova, Alena
    SMHI, Research Department, Hydrology.
    Cooke, Richard A.
    Intra-Annual Variability of Riverine Nutrient and Sediment Loadings Using Weighted Circular Statistics2018In: Journal of environmental engineering, ISSN 0733-9372, E-ISSN 1943-7870, Vol. 144, no 3, article id 04018010Article in journal (Refereed)
  • 1592. Vesakoski, Jenni-Mari
    et al.
    Nylen, Tua
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Gustafsson, David
    SMHI, Research Department, Hydrology.
    Isberg, Kristina
    SMHI, Research Department, Hydrology.
    Holopainen, Markus
    Hyyppa, Juha
    Alho, Petteri
    Arctic Mackenzie Delta channel planform evolution during 1983-2013 utilising Landsat data and hydrological time series2017In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 31, no 22, p. 3979-3995Article in journal (Refereed)
  • 1593. Vetter, Tobias
    et al.
    Reinhardt, Julia
    Floerke, Martina
    van Griensven, Ann
    Hattermann, Fred
    Huang, Shaochun
    Koch, Hagen
    Pechlivanidis, Ilias
    SMHI, Research Department, Hydrology.
    Ploetner, Stefan
    Seidou, Ousmane
    Su, Buda
    Vervoort, R. Willem
    Krysanova, Valentina
    Evaluation of sources of uncertainty in projected hydrological changes under climate change in 12 large-scale river basins2017In: Climatic Change, ISSN 0165-0009, E-ISSN 1573-1480, Vol. 141, no 3, p. 419-433Article in journal (Refereed)
  • 1594. Viney, Neil R.
    et al.
    Bormann, H.
    Breuer, L.
    Bronstert, A.
    Croke, B. F. W.
    Frede, H.
    Graeff, T.
    Hubrechts, L.
    Huisman, J. A.
    Jakeman, A. J.
    Kite, G. W.
    Lanini, J.
    Leavesley, G.
    Lettenmaier, D. P.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Seibert, J.
    Sivapalan, M.
    Willems, P.
    Assessing the impact of land use change on hydrology by ensemble modelling (LUCHEM) II: Ensemble combinations and predictions2009In: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 32, no 2, p. 147-158Article in journal (Refereed)
    Abstract [en]

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

  • 1595. Vivanco, Marta G.
    et al.
    Theobald, Mark R.
    Garcia-Gomez, Hector
    Luis Garrido, Juan
    Prank, Marje
    Aas, Wenche
    Adani, Mario
    Alyuz, Ummugulsum
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Bellasio, Roberto
    Bessagnet, Bertrand
    Bianconi, Roberto
    Bieser, Johannes
    Brandt, Jurgen
    Briganti, Gino
    Cappelletti, Andrea
    Curci, Gabriele
    Christensen, Jesper H.
    Colette, Augustin
    Couvidat, Florian
    Cuvelier, Cornelis
    D'Isidoro, Massimo
    Flemming, Johannes
    Fraser, Andrea
    Geels, Camilla
    Hansen, Kaj M.
    Hogrefe, Christian
    Im, Ulas
    Jorba, Oriol
    Kitwiroon, Nutthida
    Manders, Astrid
    Mircea, Mihaela
    Otero, Noelia
    Pay, Maria-Teresa
    Pozzoli, Luca
    Solazzo, Efisio
    Tsyro, Svetlana
    Unal, Alper
    Wind, Peter
    Galmarini, Stefano
    Modeled deposition of nitrogen and sulfur in Europe estimated by 14 air quality model systems: evaluation, effects of changes in emissions and implications for habitat protection2018In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 18, no 14, p. 10199-10218Article in journal (Refereed)
  • 1596. Voisin, Nathalie
    et al.
    Hamlet, Alan F.
    Graham, Phil
    SMHI, Research Department, Climate research - Rossby Centre.
    Pierce, David W.
    Barnett, Tim P.
    Lettenmaier, Dennis P.
    The role of climate forecasts in Western US power planning2006In: Journal of Applied Meteorology and Climatology, ISSN 1558-8424, E-ISSN 1558-8432, Vol. 45, no 5, p. 653-673Article in journal (Refereed)
    Abstract [en]

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

  • 1597. von Schuckmann, Karina
    et al.
    Le Traon, Pierre-Yves
    Alvarez-Fanjul, Enrique
    Axell, Lars
    SMHI, Research Department, Oceanography.
    Balmaseda, Magdalena
    Breivik, Lars-Anders
    Brewin, Robert J. W.
    Bricaud, Clement
    Drevillon, Marie
    Drillet, Yann
    Dubois, Clotilde
    Embury, Owen
    Etienne, Hélène
    Sotillo, Marcos García
    Garric, Gilles
    Gasparin, Florent
    Gutknecht, Elodie
    Guinehut, Stéphanie
    Hernandez, Fabrice
    Juza,, Melanie
    Karlson, Bengt
    SMHI, Research Department, Oceanography.
    Korres, Gerasimos
    Legeais, Jean-François
    Levier, Bruno
    Lien, Vidar S.
    Morrow, Rosemary
    Notarstefano, Giulio
    Parent, Laurent
    Pascual, Álvaro
    PérezGómez, Begoña
    Perruche, Coralie
    Pinardi, Nadia
    Pisano, Andrea
    Poulain, Pierre-Marie
    Pujol, Isabelle M.
    Raj, Roshin P.
    Raudsepp, Urmas
    Roquet, Hervé
    Samuelsen, Annette
    Sathyendranath, Shubha
    She, Jun
    Simoncelli, Simona
    Cosimo, Solidoro
    Tinker, Jonathan
    Tintoré, Joaquín
    Viktorsson, Lena
    SMHI, Core Services.
    Ablain, Michael
    Almroth-Rosell, Elin
    SMHI, Research Department, Oceanography.
    Bonaduce, Antonio
    Clementi, Emanuela
    Cossarini, Gianpiero
    Dagneaux, Quentin
    Desportes, Charles
    Dye, Stephen
    Fratianni, Claudia
    Good, Simon
    Greiner, Eric
    Gourrion, Jerome
    Hamon, Mathieu
    Holt, Jason
    Hyder, Pat
    Kennedy, John
    ManzanoMuñoz, Fernando
    Melet, Angélique
    Meyssignac, Benoit
    Mulet, Sandrine
    Buongiorno Nardelli, Bruno
    O´Dea, Enda
    Olason, Einar
    Paulmier, Aurélien
    Pérez-González, Irene
    Reid, Rebecca
    Racault, Marie-Fanny
    Raitsos, Dionysios E.
    Ramos,, Antonio
    Sykes, Peter
    Szekely, Tanguy
    Verbrugge, Nathalie
    The Copernicus Marine Environment Monitoring Service Ocean State Report2017In: Journal of operational oceanography. Publisher: The Institute of Marine Engineering, Science & Technology, ISSN 1755-876X, E-ISSN 1755-8778, Vol. 9, no Sup.2, p. 235-320Article in journal (Refereed)
  • 1598. Vuorinen, Ilppo
    et al.
    Hanninen, Jari
    Rajasilta, Marjut
    Laine, Paivi
    Eklund, Jan
    Montesino-Pouzols, Federico
    Corona, Francesco
    Junker, Karin
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Dippner, Joachim W.
    Scenario simulations of future salinity and ecological consequences in the Baltic Sea and adjacent North Sea areas - Implications for environmental monitoring (vol 50, pg 196, 2015)2015In: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 53, p. 294-294Article in journal (Refereed)
  • 1599. Vuorinen, Ilppo
    et al.
    Hanninen, Jari
    Rajasilta, Marjut
    Laine, Paivi
    Eklund, Jan
    Montesino-Pouzols, Federico
    Corona, Francesco
    Junker, Karin
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Dippner, Joachim W.
    Scenario simulations of future salinity and ecological consequences in the Baltic Sea and adjacent North Sea areas-implications for environmental monitoring2015In: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 50, p. 196-205Article in journal (Refereed)
    Abstract [en]

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

  • 1600.
    Väli, Germo
    et al.
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Elken, Jüri
    Marine Systems Institute at Tallinn University of Technology, Tallinn, Estonia.
    Simulated variations of the Baltic Sea halocline during 1961-20072012Report (Other academic)
    Abstract [en]

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

293031323334 1551 - 1600 of 1685
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
v. 2.35.8
|