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  • 401.
    Berg, Peter
    et al.
    SMHI, Research Department, Hydrology.
    Norin, Lars
    SMHI, Research Department, Atmospheric remote sensing.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Creation of a high resolution precipitation data set by merging gridded gauge data and radar observations for Sweden2016In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 541, p. 6-13Article in journal (Refereed)
  • 402.
    Schimanke, Semjon
    et al.
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Decadal-to-Centennial Variability of Salinity in the Baltic Sea2016In: Journal of Climate, ISSN 0894-8755, E-ISSN 1520-0442, Vol. 29, no 20, p. 7173-7188Article in journal (Refereed)
  • 403. Nijzink, Remko
    et al.
    Hutton, Christopher
    Pechlivanidis, Ilias
    SMHI, Research Department, Hydrology.
    Capell, Réne
    SMHI, Research Department, Hydrology.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Freer, Jim
    Han, Dawei
    Wagener, Thorsten
    McGuire, Kevin
    Savenije, Hubert
    Hrachowitz, Markus
    The evolution of root-zone moisture capacities after deforestation: a step towards hydrological predictions under change?2016In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 20, no 12, p. 4775-4799Article in journal (Refereed)
    Abstract [en]

    The core component of many hydrological systems, the moisture storage capacity available to vegetation, is impossible to observe directly at the catchment scale and is typically treated as a calibration parameter or obtained from a priori available soil characteristics combined with estimates of rooting depth. Often this parameter is considered to remain constant in time. Using long-term data (30–40 years) from three experimental catchments that underwent significant land cover change, we tested the hypotheses that: (1) the root-zone storage capacity significantly changes after deforestation, (2) changes in the root-zone storage capacity can to a large extent explain post-treatment changes to the hydrological regimes and that (3) a time-dynamic formulation of the root-zone storage can improve the performance of a hydrological model.A recently introduced method to estimate catchment-scale root-zone storage capacities based on climate data (i.e. observed rainfall and an estimate of transpiration) was used to reproduce the temporal evolution of root-zone storage capacity under change. Briefly, the maximum deficit that arises from the difference between cumulative daily precipitation and transpiration can be considered as a proxy for root-zone storage capacity. This value was compared to the value obtained from four different conceptual hydrological models that were calibrated for consecutive 2-year windows.It was found that water-balance-derived root-zone storage capacities were similar to the values obtained from calibration of the hydrological models. A sharp decline in root-zone storage capacity was observed after deforestation, followed by a gradual recovery, for two of the three catchments. Trend analysis suggested hydrological recovery periods between 5 and 13 years after deforestation. In a proof-of-concept analysis, one of the hydrological models was adapted to allow dynamically changing root-zone storage capacities, following the observed changes due to deforestation. Although the overall performance of the modified model did not considerably change, in 51 % of all the evaluated hydrological signatures, considering all three catchments, improvements were observed when adding a time-variant representation of the root-zone storage to the model.In summary, it is shown that root-zone moisture storage capacities can be highly affected by deforestation and climatic influences and that a simple method exclusively based on climate data can not only provide robust, catchment-scale estimates of this critical parameter, but also reflect its time-dynamic behaviour after deforestation.

  • 404. Hutton, Christopher
    et al.
    Wagener, Thorsten
    Freer, Jim
    Han, Dawei
    Duffy, Chris
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Most computational hydrology is not reproducible, so is it really science?2016In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 52, no 10, p. 7548-7555Article in journal (Refereed)
  • 405. Casini, Michele
    et al.
    Kall, Filip
    Hansson, Martin
    SMHI, Core Services.
    Plikshs, Maris
    Baranova, Tatjana
    Karlsson, Olle
    Lundstrom, Karl
    Neuenfeldt, Stefan
    Gardmark, Anna
    Hjelm, Joakim
    Hypoxic areas, density-dependence and food limitation drive the body condition of a heavily exploited marine fish predator2016In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 3, no 10, article id 160416Article in journal (Refereed)
  • 406. Tiselius, Peter
    et al.
    Belgrano, Andrea
    Andersson, Lars
    SMHI, Core Services.
    Lindahl, Odd
    Contribution to the Themed Section: Scaling from individual Plankton to marine ecosystems Primary productivity in a coastal ecosystem: a trophic perspective on a long-term time series2016In: Journal of Plankton Research, ISSN 0142-7873, E-ISSN 1464-3774, Vol. 38, no 4, p. 1092-1102Article in journal (Refereed)
  • 407.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Lake water levels for calibration of the S-HYPE model2016In: HYDROLOGY RESEARCH, ISSN 1998-9563, Vol. 47, no 4, p. 672-682Article in journal (Refereed)
  • 408. Zhang, Linus
    et al.
    Gustafsson, David
    SMHI, Research Department, Hydrology.
    Editorial: 'The Nordic Hydrology Model' - Linking science and practice2016In: HYDROLOGY RESEARCH, ISSN 1998-9563, Vol. 47, no 4, p. 671-671Article in journal (Refereed)
  • 409. Pechlivanidis, Ilias G.
    et al.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Bosshard, Thomas
    SMHI, Research Department, Hydrology.
    Sharma, Devesh
    Sharma, K. C.
    Multi-Basin Modelling of Future Hydrological Fluxes in the Indian Subcontinent2016In: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 8, no 5, article id 177Article in journal (Refereed)
    Abstract [en]

    The impact of climate change on the hydro-climatology of the Indian subcontinent is investigated by comparing statistics of current and projected future fluxes resulting from three RCP scenarios (RCP2.6, RCP4.5, and RCP8.5). Climate projections from the CORDEX-South Asia framework have been bias-corrected using the Distribution-Based Scaling (DBS) method and used to force the HYPE hydrological model to generate projections of evapotranspiration, runoff, soil moisture deficit, snow depth, and applied irrigation water to soil. We also assess the changes in the annual cycles in three major rivers located in different hydro-climatic regions. Results show that conclusions can be influenced by uncertainty in the RCP scenarios. Future scenarios project a gradual increase in temperature (up to 7 degrees C on average), whilst changes (both increase and decrease) in the long-term average precipitation and evapotranspiration are more severe at the end of the century. The potential change (increase and decrease) in runoff could reach 100% depending on the region and time horizon. Analysis of annual cycles for three selected regions showed that changes in discharge and evapotranspiration due to climate change vary between seasons, whereas the magnitude of change is dependent on the region's hydro-climatic gradient. Irrigation needs and the snow depth in the Himalayas are also affected.

  • 410. Enmar, Linda
    et al.
    Lake, Irene
    SMHI, Research Department, Oceanography.
    Lundberg, Peter
    Sigray, Peter
    A note on ADCP-based indirect observations of turbulence2016In: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 21, no 1-2, p. 44-52Article in journal (Refereed)
    Abstract [en]

    A 70-day data set from bottom-mounted ADCPs on the two sides of the Faroe-Bank Channel was analysed using the recorded flow variance and echo intensity in the deeper reaches of the passage as proxies for turbulence. A consistent picture emerged, not least since the data losses (which were ascribed to turbulence-induced activation of the fish-elimination option in the ADCP software) could be shown to co-vary with the internal M-2 tide affecting the vertical shear, which in turn proved to be correlated with the flow variance.

  • 411. Akselsson, Cecilia
    et al.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Belyazid, Salim
    Capell, Réne
    SMHI, Research Department, Hydrology.
    Can increased weathering rates due to future warming compensate for base cation losses following whole-tree harvesting in spruce forests?2016In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 128, no 1-2, p. 89-105Article in journal (Refereed)
  • 412. Roudier, Philippe
    et al.
    Andersson, Jafet
    SMHI, Research Department, Hydrology.
    Donnelly, Chantal
    SMHI, Research Department, Hydrology.
    Feyen, Luc
    Greuell, Wouter
    Ludwig, Fulco
    Projections of future floods and hydrological droughts in Europe under a+2 degrees C global warming2016In: Climatic Change, ISSN 0165-0009, E-ISSN 1573-1480, Vol. 135, no 2, p. 341-355Article in journal (Refereed)
  • 413. Hu, Yue O. O.
    et al.
    Karlson, Bengt
    SMHI, Research Department, Oceanography.
    Charvet, Sophie
    Andersson, Anders F.
    Diversity of Pico- to Mesoplankton along the 2000 km Salinity Gradient of the Baltic Sea2016In: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 7, article id 679Article in journal (Refereed)
  • 414. Enmar, Linda
    et al.
    Lake, Irene
    SMHI, Research Department.
    Lundberg, Peter
    Sigray, Peter
    A note on ADCP-based indirect observations of turbulence2016In: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 21, no 1-2, p. 44-52Article in journal (Refereed)
  • 415. Pechlivanidis, Ilias G.
    et al.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Bosshard, Thomas
    SMHI, Research Department, Hydrology.
    Sharma, Devesh
    Sharma, K. C.
    Multi-Basin Modelling of Future Hydrological Fluxes in the Indian Subcontinent2016In: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 8, no 5, p. 177-177Article in journal (Refereed)
    Abstract [en]

    The impact of climate change on the hydro-climatology of the Indian subcontinent is investigated by comparing statistics of current and projected future fluxes resulting from three RCP scenarios (RCP2.6, RCP4.5, and RCP8.5). Climate projections from the CORDEX-South Asia framework have been bias-corrected using the Distribution-Based Scaling (DBS) method and used to force the HYPE hydrological model to generate projections of evapotranspiration, runoff, soil moisture deficit, snow depth, and applied irrigation water to soil. We also assess the changes in the annual cycles in three major rivers located in different hydro-climatic regions. Results show that conclusions can be influenced by uncertainty in the RCP scenarios. Future scenarios project a gradual increase in temperature (up to 7 degrees C on average), whilst changes (both increase and decrease) in the long-term average precipitation and evapotranspiration are more severe at the end of the century. The potential change (increase and decrease) in runoff could reach 100% depending on the region and time horizon. Analysis of annual cycles for three selected regions showed that changes in discharge and evapotranspiration due to climate change vary between seasons, whereas the magnitude of change is dependent on the region's hydro-climatic gradient. Irrigation needs and the snow depth in the Himalayas are also affected.

  • 416. Aich, Valentin
    et al.
    Liersch, Stefan
    Vetter, Tobias
    Fournet, Samuel
    Andersson, Jafet
    SMHI, Research Department, Hydrology.
    Calmanti, Sandro
    van Weert, Frank H. A.
    Hattermann, Fred F.
    Paton, Eva N.
    Flood projections within the Niger River Basin under future land use and climate change2016In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 562, p. 666-677Article in journal (Refereed)
    Abstract [en]

    This study assesses future flood risk in the Niger River Basin (NRB), for the first time considering the simultaneous effects of both projected climate change and land use changes. For this purpose, an ecohydrological process-based model (SWIM) was set up and validated for past climate and land use dynamics of the entire NRB. Model runs for future flood risks were conducted with an ensemble of 18 climate models, 13 of them dynamically downscaled from the CORDEX Africa project and five statistically downscaled Earth System Models. Two climate and two land use change scenarios were used to cover a broad range of potential developments in the region. Two flood indicators (annual 90th percentile and the 20-year return flood) were used to assess the future flood risk for the Upper, Middle and Lower Niger as well as the Benue. The modeling results generally show increases of flood magnitudes when comparing a scenario period in the near future (2021-2050) with a base period (1976-2005). Land use effects are more uncertain, but trends and relative changes for the different catchments of the NRB seem robust. The dry areas of the Sahelian and Sudanian regions of the basin show a particularly high sensitivity to climatic and land use changes, with an alarming increase of flood magnitudes in parts. A scenario with continuing transformation of natural vegetation into agricultural land and urbanization intensifies the flood risk in all parts of the NRB, while a "regreening" scenario can reduce flood magnitudes to some extent. Yet, land use change effects were smaller when compared to the effects of climate change. In the face of an already existing adaptation deficit to catastrophic flooding in the region, the authors argue for a mix of adaptation and mitigation efforts in order to reduce the flood risk in the NRB. (C) 2016 Elsevier B.V. All rights reserved.

  • 417.
    Olsson, Jonas
    et al.
    SMHI, Research Department, Hydrology.
    Uvo, C. B.
    Foster, Kean
    SMHI, Research Department, Hydrology.
    Yang, Wei
    SMHI, Research Department, Hydrology.
    Technical Note: Initial assessment of a multi-method approach to spring-flood forecasting in Sweden2016In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 20, no 2, p. 659-667Article in journal (Refereed)
    Abstract [en]

    Hydropower is a major energy source in Sweden, and proper reservoir management prior to the spring-flood onset is crucial for optimal production. This requires accurate forecasts of the accumulated discharge in the spring-flood period (i.e. the spring-flood volume, SFV). Today's SFV forecasts are generated using a model-based climatological ensemble approach, where time series of precipitation and temperature from historical years are used to force a calibrated and initialized set-up of the HBV model. In this study, a number of new approaches to spring-flood forecasting that reflect the latest developments with respect to analysis and modelling on seasonal timescales are presented and evaluated. Three main approaches, represented by specific methods, are evaluated in SFV hindcasts for the Swedish river Vindelalven over a 10-year period with lead times between 0 and 4 months. In the first approach, historically analogue years with respect to the climate in the period preceding the spring flood are identified and used to compose a reduced ensemble. In the second, seasonal meteorological ensemble forecasts are used to drive the HBV model over the spring-flood period. In the third approach, statistical relationships between SFV and the large-sale atmospheric circulation are used to build forecast models. None of the new approaches consistently outperform the climatological ensemble approach, but for early forecasts improvements of up to 25% are found. This potential is reasonably well realized in a multi-method system, which over all forecast dates reduced the error in SFV by similar to 4 %. This improvement is limited but potentially significant for e.g. energy trading.

  • 418. Emerton, Rebecca E.
    et al.
    Stephens, Elisabeth M.
    Pappenberger, Florian
    Pagano, Thomas C.
    Weerts, Albrecht H.
    Wood, Andy W.
    Salamon, Peter
    Brown, James D.
    Hjerdt, Niclas
    SMHI, Core Services.
    Donnelly, Chantal
    SMHI, Research Department, Hydrology.
    Baugh, Calum A.
    Cloke, Hannah L.
    Continental and global scale flood forecasting systems2016In: WILEY INTERDISCIPLINARY REVIEWS-WATER, Vol. 3, no 3, p. 391-418Article in journal (Refereed)
    Abstract [en]

    Floods are the most frequent of natural disasters, affecting millions of people across the globe every year. The anticipation and forecasting of floods at the global scale is crucial to preparing for severe events and providing early awareness where local flood models and warning services may not exist. As numerical weather prediction models continue to improve, operational centers are increasingly using their meteorological output to drive hydrological models, creating hydrometeorological systems capable of forecasting river flow and flood events at much longer lead times than has previously been possible. Furthermore, developments in, for example, modelling capabilities, data, and resources in recent years have made it possible to produce global scale flood forecasting systems. In this paper, the current state of operational large-scale flood forecasting is discussed, including probabilistic forecasting of floods using ensemble prediction systems. Six state-of-the-art operational large-scale flood forecasting systems are reviewed, describing similarities and differences in their approaches to forecasting floods at the global and continental scale. Operational systems currently have the capability to produce coarse-scale discharge forecasts in the medium-range and disseminate forecasts and, in some cases, early warning products in real time across the globe, in support of national forecasting capabilities. With improvements in seasonal weather forecasting, future advances may include more seamless hydrological forecasting at the global scale alongside a move towards multi-model forecasts and grand ensemble techniques, responding to the requirement of developing multi-hazard early warning systems for disaster risk reduction. (C) 2016 The Authors. WIREs Water published by Wiley Periodicals, Inc.

  • 419. Fransner, Filippa
    et al.
    Nycander, Jonas
    Morth, Carl-Magnus
    Humborg, Christoph
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Hordoir, Robinson
    SMHI, Research Department, Oceanography.
    Gustafsson, Erik
    Deutsch, Barbara
    Tracing terrestrial DOC in the Baltic SeaA 3-D model study2016In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 30, no 2, p. 134-148Article in journal (Refereed)
    Abstract [en]

    The fate of terrestrial organic matter brought to the coastal seas by rivers and its role in the global carbon cycle are still not very well known. Here the degradation rate of terrestrial dissolved organic carbon (DOCter) is studied in the Baltic Sea, a subarctic semienclosed sea, by releasing it as a tracer in a 3-D circulation model and applying linear decay constants. A good agreement with available observational data is obtained by parameterizing the degradation in two rather different ways: one by applying a decay time on the order of 10years to the whole pool of DOCter and one by dividing the DOCter into onerefractory pool and one pool subject to a decay time on the order of 1year. The choice ofparameterization has asignificant effect on where in the Baltic Sea the removal takes place, which can be of importance whenmodeling the full carbon cycle and the CO2 exchange with the atmosphere. In both cases the biogeochemical decayoperates on time scales less than the water residence time. Therefore, only a minor fraction of the DOCter reaches the North Sea, whereas approximately 80% is removed by internal sinks within the Baltic Sea. This further implies that DOCter mineralization is an important link in land-sea-atmosphere cycling of carbon in coastal and shelf seas that are heavily influenced by riverine DOC.

  • 420.
    Donnelly, Chantal
    et al.
    SMHI, Research Department, Hydrology.
    Andersson, Jafet
    SMHI, Research Department, Hydrology.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Using flow signatures and catchment similarities to evaluate the E-HYPE multi-basin model across Europe2016In: Hydrological Sciences Journal, ISSN 0262-6667, E-ISSN 2150-3435, Vol. 61, no 2, p. 255-273Article in journal (Refereed)
    Abstract [en]

    Open data make it possible to set up multi-basin models for large domains across environmental, climate and administrative boundaries. This study presents new methods for evaluating a number of aspects of multi-basin model performance, while exploring the performance of the E-HYPE_v2.1 model for several evaluation criteria in 181 independent river gauges across the European continent. Embedded model assumptions on dominant flow generating mechanisms are analysed by correlating physiographical characteristics to the flow regime. The results indicate that the model captures the spatial variability of flow and is therefore suitable for predictions in ungauged basins. The model shows good performance of long-term means and seasonality, while short-term daily variability is less well represented, especially for Mediterranean and mountainous areas. Major identified shortcomings refer to the resolution of precipitation patterns, aquifer exchanges, water extractions and regulation. This will guide the work with the next model version for which improvements in input data, processes and calibration have been identified to potentially contribute most to improved model performance. [GRAPHICS]

  • 421.
    Pemberton, Per
    et al.
    SMHI, Research Department, Oceanography.
    Nilsson, J.
    The response of the central Arctic Ocean stratification to freshwater perturbations2016In: Journal of Geophysical Research - Oceans, ISSN 2169-9275, E-ISSN 2169-9291, Vol. 121, no 1, p. 792-817Article in journal (Refereed)
    Abstract [en]

    Using a state-of-the-art coupled ice-ocean-circulation model, we perform a number of sensitivity experiments to examine how the central Arctic Ocean stratification responds to changes in river runoff and precipitation. The simulations yield marked changes in the cold halocline and the Arctic Atlantic layer. Increased precipitation yields a warming of the Atlantic layer, which primarily is an advective signal, propagated through the St. Anna Trough, reflecting air-sea heat flux changes over the Barents Sea. As the freshwater supply is increased, the anticyclonic Beaufort Gyre is weakened and a greater proportion of the Arctic Ocean freshwater is exported via the Fram Strait, with nearly compensating export decreases through the Canadian Arctic Archipelago. The corresponding reorganization of the freshwater pool appears to be controlled by advective processes, rather than by the local changes in the surface freshwater flux. A simple conceptual model of the Arctic Ocean, based on a geostrophically controlled discharge of the low-salinity water, is introduced and compared with the simulations. Key predictions of the conceptual model are that the halocline depth should decrease with increasing freshwater input and that the Arctic Ocean freshwater storage should increase proportionally to the square root of the freshwater input, which are in broad qualitative agreement with the sensitivity experiments. However, the model-simulated rate of increase of the freshwater storage is weaker, indicating that effects related to wind forcing and rerouting of the freshwater-transport pathways play an important role for the dynamics of the Arctic Ocean freshwater storage.

  • 422.
    Axell, Lars
    et al.
    SMHI, Research Department, Oceanography.
    Liu, Ye
    SMHI, Research Department, Oceanography.
    Application of 3-D ensemble variational data assimilation to a Baltic Sea reanalysis 1989-20132016In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 68, article id 24220Article in journal (Refereed)
    Abstract [en]

    A 3-D ensemble variational (3DEnVar) data assimilation method has been implemented and tested for oceanographic data assimilation of sea surface temperature (SST), sea surface salinity (SSS), sea ice concentration (SIC), and salinity and temperature profiles. To damp spurious long-range correlations in the ensemble statistics, horizontal and vertical localisation was implemented using empirical orthogonal functions. The results show that the 3DEnVar method is indeed possible to use in oceanographic data assimilation. So far, only a seasonally dependent ensemble has been used, based on historical model simulations. Near-surface experiments showed that the ensemble statistics gave inhomogeneous and anisotropic horizontal structure functions, and assimilation of real SST and SIC fields gave smooth, realistic increment fields. The implementation was multivariate, and results showed that the cross-correlations between variables work in an intuitive way, for example, decreasing SST where SIC was increased and vice versa. The profile data assimilation also gave good results. The results from a 25-year reanalysis showed that the vertical salinity and temperature structure were significantly improved, compared to both dependent and independent data.

  • 423.
    Pechlivanidis, Ilias
    et al.
    SMHI, Research Department, Hydrology.
    Jackson, Bethanna
    Mcmillan, Hilary
    Gupta, Hoshin V.
    Robust informational entropy-based descriptors of flow in catchment hydrology2016In: Hydrological Sciences Journal, ISSN 0262-6667, E-ISSN 2150-3435, Vol. 61, no 1, p. 1-18Article in journal (Refereed)
    Abstract [en]

    This paper explores the use of entropy-based measures in catchment hydrology, and provides an importance-weighted numerical descriptor of the flow-duration curve. Although entropy theory is being applied in a wide spectrum of areas (including environmental and water resources), artefacts arising from the discrete, under-sampled and uncertain nature of hydrological data are rarely acknowledged, and have not been adequately explored. Here, we examine challenges to extracting hydrologically meaningful entropy measures from a flow signal; the effect of binning resolution on calculation of entropy is investigated, along with artefacts caused by (1) emphasis of information theoretic measures towards flow ranges having more data (statistically dominant information), and (2) effects of discharge measurement truncation errors. We introduce an importance-weighted entropy-based measure to counter the tendency of common binning approaches to over-emphasise information contained in the low flows which dominate the record. The measure uses a novel binning method, and overcomes artefacts due to data resolution and under-sampling. Our analysis reveals a fundamental problem with the extraction of information at high flows, due to the lack of statistically significant samples in this range. By separating the flow-duration curve into segments, our approach constrains the computed entropy to better respect distributional properties over the data range. When used as an objective function for model calibration, this approach constrains high flow predictions, as well as the commonly used Nash-Sutcliffe efficiency, but provides much better predictions of low flow behaviour.

  • 424. Yin, Yunxing
    et al.
    Jiang, Sanyuan
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Yang, Xiaoying
    Liu, Qun
    Yuan, Jin
    Yao, Mingxing
    He, Yi
    Luo, Xingzhang
    Zheng, Zheng
    Assessment of the Spatial and Temporal Variations of Water Quality for Agricultural Lands with Crop Rotation in China by Using a HYPE Model2016In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 13, no 3Article in journal (Refereed)
    Abstract [en]

    Many water quality models have been successfully used worldwide to predict nutrient losses from anthropogenically impacted catchments, but hydrological and nutrient simulations with limited data are difficult considering the transfer of model parameters and complication of model calibration and validation. This study aims: (i) to assess the performance capabilities of a new and relatively more advantageous model, namely, Hydrological Predictions for the Environment (HYPE), that simulates stream flow and nutrient load in agricultural areas by using a multi-site and multi-objective parameter calibration method and (ii) to investigate the temporal and spatial variations of total nitrogen (TN) and total phosphorous (TP) concentrations and loads with crop rotation by using the model for the first time. A parameter estimation tool (PEST) was used to calibrate parameters. Results show that the parameters related to the effective soil porosity were highly sensitive to hydrological modeling. N balance was largely controlled by soil denitrification processes. P balance was influenced by the sedimentation rate and production/decay of P in rivers and lakes. The model reproduced the temporal and spatial variations of discharge and TN/TP relatively well in both calibration (2006-2008) and validation (2009-2010) periods. Among the obtained data, the lowest Nash-Suttclife efficiency of discharge, daily TN load, and daily TP load were 0.74, 0.51, and 0.54, respectively. The seasonal variations of daily TN concentrations in the entire simulation period were insufficient, indicated that crop rotation changed the timing and amount of N output. Monthly TN and TP simulation yields revealed that nutrient outputs were abundant in summer in terms of the corresponding discharge. The area-weighted TN and TP load annual yields in five years showed that nutrient loads were extremely high along Hong and Ru rivers, especially in agricultural lands.

  • 425. Winterdahl, Mattias
    et al.
    Laudon, Hjalmar
    Lyon, Steve W.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Bishop, Kevin
    Sensitivity of stream dissolved organic carbon to temperature and discharge: Implications of future climates2016In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 121, no 1, p. 126-144Article in journal (Refereed)
    Abstract [en]

    Dissolved organic carbon (DOC) is a significant constituent in aquatic ecosystems with concentrations in streams influenced by both temperature and water flow pathway dynamics associated with changes in discharge (streamflow). We investigated the sensitivity of DOC concentrations in 12 high-latitude headwater streams to changes in temperature and discharge using a mathematical model. The implications of differences in sensitivities were explored by using downscaled projections of air temperature and discharge to simulate possible trajectories of DOC concentrations in a changing climate. We found two distinct responses: (i) catchments where stream DOC sensitivity was high to temperature but low to discharge and (ii) catchments where stream DOC sensitivity was low to temperature but high to discharge. Streams with strong seasonal DOC dynamics were more sensitive to temperature changes than nonseasonal systems. In addition, stream DOC sensitivity to discharge was strongly correlated with vertical soil water DOC differences in the near-stream zone. Simulations of possible future changes in DOC concentrations indicated median increases of about 4-24% compared to current levels when using projections of air temperature and discharge but even larger increases were observed for base flow concentrations (13-42%). Streams with high-temperature sensitivity showed the largest increases in DOC concentrations. Our results suggest that future climatic changes could bring significant increases in surface water DOC concentrations in boreal and hemiboreal areas but that the response ultimately is dependent on vertical soil solution DOC differences and soil organic carbon distribution.

  • 426. Wu, Minchao
    et al.
    Schurgers, Guy
    Rummukainen, Markku
    SMHI, Core Services.
    Smith, Benjamin
    Samuelsson, Patrick
    SMHI, Research Department, Climate research - Rossby Centre.
    Jansson, Christer
    Siltberg, Joe
    May, Wilhelm
    Vegetation-climate feedbacks modulate rainfall patterns in Africa under future climate change2016In: Earth System Dynamics, ISSN 2190-4979, E-ISSN 2190-4987, Vol. 7, no 3, p. 627-647Article in journal (Refereed)
  • 427. 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.

  • 428. Pareeth, Sajid
    et al.
    Delucchi, Luca
    Metz, Markus
    Rocchini, Duccio
    Devasthale, Abhay
    SMHI, Research Department, Atmospheric remote sensing.
    Raspaud, Martin
    SMHI, Core Services.
    Adrian, Rita
    Salmaso, Nico
    Neteler, Markus
    New Automated Method to Develop Geometrically Corrected Time Series of Brightness Temperatures from Historical AVHRR LAC Data2016In: Remote Sensing, ISSN 2072-4292, E-ISSN 2072-4292, Vol. 8, no 3, p. NIL_481-NIL_508Article in journal (Refereed)
    Abstract [en]

    Analyzing temporal series of satellite data for regional scale studies demand high accuracy in calibration and precise geo-rectification at higher spatial resolution. The Advanced Very High Resolution Radiometer (AVHRR) sensor aboard the National Oceanic and Atmospheric Administration (NOAA) series of satellites provide daily observations for the last 30 years at a nominal resolution of 1.1 km at nadir. However, complexities due to on-board malfunctions and orbital drifts with the earlier missions hinder the usage of these images at their original resolution. In this study, we developed a new method using multiple open source tools which can read level 1B radiances, apply solar and thermal calibration to the channels, remove bow-tie effects on wider zenith angles, correct for clock drifts on earlier images and perform precise geo-rectification by automated generation and filtering of ground control points using a feature matching technique. The entire workflow is reproducible and extendable to any other geographical location. We developed a time series of brightness temperature maps from AVHRR local area coverage images covering the sub alpine lakes of Northern Italy at 1 km resolution (1986-2014; 28 years). For the validation of derived brightness temperatures, we extracted Lake Surface Water Temperature (LSWT) for Lake Garda in Northern Italy and performed inter-platform (NOAA-x vs. NOAA-y) and cross-platform (NOAA-x vs. MODIS/ATSR/AATSR) comparisons. The MAE calculated over available same day observations between the pairs-NOAA-12/14, NOAA-17/18 and NOAA-18/19 are 1.18 K, 0.67 K, 0.35 K, respectively. Similarly, for cross-platform pairs, the MAE varied between 0.5 to 1.5 K. The validation of LSWT from various NOAA instruments with in-situ data shows high accuracy with mean R-2 and RMSE of 0.97 and 0.91 K respectively.

  • 429. Markakis, Konstantinos
    et al.
    Valari, Myrto
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Lacressonniere, Gwendoline
    Vautard, Robert
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Mid-21st century air quality at the urban scale under the influence of changed climate and emissions - case studies for Paris and Stockholm2016In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, no 4, p. 1877-1894Article in journal (Refereed)
    Abstract [en]

    Ozone, PM10 and PM2.5 concentrations over Paris, France and Stockholm, Sweden were modelled at 4 and 1 km horizontal resolutions respectively for the present and 2050 periods employing decade-long simulations. We account for large-scale global climate change (RCP-4.5) and fine-resolution bottom-up emission projections developed by local experts and quantify their impact on future pollutant concentrations. Moreover, we identify biases related to the implementation of regional-scale emission projections by comparing modelled pollutant concentrations between the fine-and coarse-scale simulations over the study areas. We show that over urban areas with major regional contribution (e.g. the city of Stockholm) the bias related to coarse-scale projections may be significant and lead to policy misclassification. Our results stress the need to better understand the mechanism of bias propagation across the modelling scales in order to design more successful local-scale strategies. We find that the impact of climate change is spatially homogeneous in both regions, implying strong regional influence. The climate benefit for ozone (daily mean and maximum) is up to 5% for Paris and 2% for Stockholm city. The climate benefit on PM2.5 and PM10 in Paris is between 5 and 10 %, while for Stockholm we estimate mixed trends of up to 3% depending on season and size class. In Stockholm, emission mitigation leads to concentration reductions up to 15% for daily mean and maximum ozone and 20% for PM. Through a sensitivity analysis we show that this response is entirely due to changes in emissions at the regional scale. On the contrary, over the city of Paris (VOC-limited photochemical regime), local mitigation of NO x emissions increases future ozone concentrations due to ozone titration inhibition. This competing trend between the respective roles of emission and climate change, results in an increase in 2050 daily mean ozone by 2.5% in Paris. Climate and not emission change appears to be the most influential factor for maximum ozone concentration over the city of Paris, which may be particularly interesting from a health impact perspective.

  • 430. Borrego, C.
    et al.
    Amorim, Jorge Humberto
    SMHI, Research Department, Air quality.
    Tchepel, O.
    Dias, D.
    Rafael, S.
    Sa, E.
    Pimentel, C.
    Fontes, T.
    Fernandes, P.
    Pereira, S. R.
    Bandeira, J. M.
    Coelho, M. C.
    Urban scale air quality modelling using detailed traffic emissions estimates2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 131, p. 341-351Article in journal (Refereed)
    Abstract [en]

    The atmospheric dispersion of NOx and PM10 was simulated with a second generation Gaussian model over a medium-size south-European city. Microscopic traffic models calibrated with GPS data were used to derive typical driving cycles for each road link, while instantaneous emissions were estimated applying a combined Vehicle Specific Power/Co-operative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (VSP/EMEP) methodology. Site-specific background concentrations were estimated using time series analysis and a low-pass filter applied to local observations. Air quality modelling results are compared against measurements at two locations for a 1 week period. 78% of the results are within a factor of two of the observations for 1-h average concentrations, increasing to 94% for daily averages. Correlation significantly improves when background is added, with an average of 0.89 for the 24 h record. The results highlight the potential of detailed traffic and instantaneous exhaust emissions estimates, together with filtered urban background, to provide accurate input data to Gaussian models applied at the urban scale. (C) 2016 Elsevier Ltd. All rights reserved.

  • 431.
    Friman, Mathias
    SMHI.
    Consensus rationales in negotiating historical responsibility for climate change2016In: International Environmental Agreements: Politics, Law and Economics, ISSN 1567-9764, E-ISSN 1573-1553, Vol. 16, no 2, p. 285-305Article in journal (Refereed)
    Abstract [en]

    This article explores strategies in consensus-making processes in international climate diplomacy. Specifically, it examines the consensus-making politics, in the case of negotiating historical responsibility within the UN Framework Convention on Climate Change. In doing so, analytical concepts from the discourse theory of Laclau and Mouffe are utilized to look for rationales that underpin discursive structures as well as agreement. To conclude, three rationales have dealt with conflicts over historical responsibility. While the first rationale hid conflict behind interpretative flexibility, the second reverted to "reasoned consensus," excluding perspectives commonly understood as political rather than scientific. The third rationale has enabled equivocal use of the concept of historical responsibility in several parallel discourses, yet negotiators still stumble on how to synthesize these with a potential to foster future, more policy-detailed, consensuses with higher legitimacy. Understanding the history and current situation of negotiations on historical responsibility from this perspective can help guide policy makers toward decisions that avoid old pitfalls and construct new rationales that generate a higher sense of legitimacy.

  • 432.
    Bengtsson, Lisa
    et al.
    SMHI, Research Department, Meteorology.
    Körnich, Heiner
    SMHI, Research Department, Meteorology.
    Impact of a stochastic parametrization of cumulus convection, using cellular automata, in a mesoscale ensemble prediction system2016In: Quarterly Journal of the Royal Meteorological Society, ISSN 0035-9009, E-ISSN 1477-870X, Vol. 142, no 695, p. 1150-1159Article in journal (Refereed)
    Abstract [en]

    A stochastic parametrization for deep convection, based on cellular automata, has been evaluated in the high-resolution (2.5 km) ensemble prediction system Hirlam Aladin Regional Mesoscale Operational NWP Ensemble Prediction System (HarmonEPS). We studied whether such a stochastic physical parametrization, whilst implemented in a deterministic forecast model, can have an impact on the performance of the uncertainty estimates given by an ensemble prediction system. Various feedback mechanisms in the parametrization were studied with respect to ensemble spread and skill, in both subgrid and resolved precipitation fields. It was found that the stochastic parametrization improves the model skill in general, by reducing a positive bias in precipitation. This reduction in bias, however, led to a reduction in ensemble spread of precipitation. Overall, scores that measure the accuracy and reliability of probabilistic predictions indicate that the net impact (improved skill, degraded spread) of the ensemble prediction system is improved for 6 h accumulated precipitation with the stochastic parametrization and is rather neutral for other quantities examined.

  • 433. Sand, M.
    et al.
    Berntsen, T. K.
    von Salzen, K.
    Flanner, M. G.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Victor, D. G.
    Response of Arctic temperature to changes in emissions of short-lived climate forcers2016In: Nature Climate Change, ISSN 1758-678X, E-ISSN 1758-6798, Vol. 6, no 3, p. 286-+Article in journal (Refereed)
    Abstract [en]

    There is growing scientific(1,2) and political(3,4) interest in the impacts of climate change and anthropogenic emissions on the Arctic. Over recent decades temperatures in the Arctic have increased at twice the global rate, largely as a result of ice-albedo and temperature feedbacks(5-8). Although deep cuts in global CO2 emissions are required to slow this warming, there is also growing interest in the potential for reducing short-lived climate forcers (SLCFs; refs 9,10). Politically, action on SLCFs may be particularly promising because the benefits of mitigation are seen more quickly than for mitigation of CO2 and there are large co-benefits in terms of improved air quality(11). This Letter is one of the first to systematically quantify the Arctic climate impact of regional SLCFs emissions, taking into account black carbon (BC), sulphur dioxide (SO2), nitrogen oxides (NOx), volatile organic compounds (VOCs), organic carbon (OC) and tropospheric ozone (O-3), and their transport processes and transformations in the atmosphere. This study extends the scope of previous works(2,12) by including more detailed calculations of Arctic radiative forcing and quantifying the Arctic temperature response. We find that the largest Arctic warming source is from emissions within the Asian nations owing to the large absolute amount of emissions. However, the Arctic is most sensitive, per unit mass emitted, to SLCFs emissions from a small number of activities within the Arctic nations themselves. Astringent, but technically feasible mitigation scenario for SLCFs, phased in from 2015 to 2030, could cut warming by 0.2 (+/- 0.17) K in 2050.

  • 434. Guemas, Virginie
    et al.
    Blanchard-Wrigglesworth, Edward
    Chevallier, Matthieu
    Day, Jonathan J.
    Deque, Michel
    Doblas-Reyes, Francisco J.
    Fuckar, Neven S.
    Germe, Agathe
    Hawkins, Ed
    Keeley, Sarah
    Koenigk, Torben
    SMHI, Research Department, Climate research - Rossby Centre.
    Salas y Melia, David
    Tietsche, Steffen
    A review on Arctic sea-ice predictability and prediction on seasonal to decadal time-scales2016In: Quarterly Journal of the Royal Meteorological Society, ISSN 0035-9009, E-ISSN 1477-870X, Vol. 142, no 695, p. 546-561Article in journal (Refereed)
    Abstract [en]

    Sea ice plays a crucial role in the Earth's energy and water budget and has a substantial impact on local and remote atmospheric and oceanic circulations. Predictions of Arctic sea-ice conditions a few months to a few years in advance could be of interest for stakeholders. This article presents a review of the potential sources of Arctic sea-ice predictability on these time-scales. Predictability mainly originates from persistence or advection of sea-ice anomalies, interactions with the ocean and atmosphere and changes in radiative forcing. After estimating the inherent potential predictability limit with state-of-the-art models, current sea-ice forecast systems are described, together with their performance. Finally, some challenges and issues in sea-ice forecasting are presented, along with suggestions for future research priorities.

  • 435. Favre, Alice
    et al.
    Philippon, Nathalie
    Pohl, Benjamin
    Kalognomou, Evangelia-Anna
    Lennard, Christopher
    Hewitson, Bruce
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Dosio, Alessandro
    Panitz, Hans-Juergen
    Cerezo-Mota, Ruth
    Spatial distribution of precipitation annual cycles over South Africa in 10 CORDEX regional climate model present-day simulations2016In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 46, no 5-6, p. 1799-1818Article in journal (Refereed)
    Abstract [en]

    This study presents an evaluation of the ability of 10 regional climate models (RCMs) participating in the COordinated Regional climate Downscaling Experiment-Africa to reproduce the present-day spatial distribution of annual cycles of precipitation over the South African region and its borders. As found in previous studies, annual mean precipitation is quasi-systematically overestimated by the RCMs over a large part of southern Africa south of about 20A degrees S and more strongly over South Africa. The spatial analysis of precipitation over the studied region shows that in most models the distribution of biases appears to be linked to orography. Wet biases are quasi-systematic in regions with higher elevation with inversely neutral to dry biases particularly in the coastal fringes. This spatial pattern of biases is particularly obvious during summer and specifically at the beginning of the rainy season (November and December) when the wet biases are found to be the strongest across all models. Applying a k-means algorithm, a classification of annual cycles is performed using observed precipitation data, and is compared with those derived from modeled data. It is found that the in-homogeneity of the spatial and temporal distribution of biases tends to impact the modeled seasonality of precipitation. Generally, the pattern of rainfall seasonality in the ensemble mean of the 10 RCMs tends to be shifted to the southwest. This spatial shift is mainly linked to a strong overestimation of convective precipitation at the beginning of the rainy season over the plateau inducing an early annual peak and to an underestimation of stratiform rainfall in winter and spring over southwestern South Africa.

  • 436.
    Wilcke, Renate
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Bärring, Lars
    SMHI, Research Department, Climate research - Rossby Centre.
    Selecting regional climate scenarios for impact modelling studies2016In: Environmental Modelling & Software, ISSN 1364-8152, E-ISSN 1873-6726, Vol. 78, p. 191-201Article in journal (Refereed)
    Abstract [en]

    In climate change research ensembles of climate simulations are produced in an attempt to cover the uncertainty in future projections. Many climate change impact studies face difficulties using the full number of simulations available, and therefore often only subsets are used. Until now such subsets were chosen based on their representation of temperature change or by accessibility of the simulations. By using more specific information about the needs of the impact study as guidance for the clustering of simulations, the subset fits the purpose of climate change impact research more appropriately. Here, the sensitivity of such a procedure is explored, particularly with regard to the use of different climate variables, seasons, and regions in Europe. While temperature dominates the clustering, the resulting selection is influenced by all variables, leading to the conclusion that different subsets fit different impact studies best. (C) 2016 The Authors. Published by Elsevier Ltd.

  • 437. Prein, A. F.
    et al.
    Gobiet, A.
    Truhetz, H.
    Keuler, K.
    Goergen, K.
    Teichmann, C.
    Maule, C. Fox
    van Meijgaard, E.
    Deque, M.
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Vautard, R.
    Colette, A.
    Kjellström, Erik
    SMHI, Research Department, Climate research - Rossby Centre.
    Jacob, D.
    Precipitation in the EURO-CORDEX 0.11 degrees and 0.44 degrees simulations: high resolution, high benefits?2016In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 46, no 1-2, p. 383-412Article in journal (Refereed)
    Abstract [en]

    In the framework of the EURO-CORDEX initiative an ensemble of European-wide high-resolution regional climate simulations on a 0.11 degrees (similar to 12.5 km) grid has been generated. This study investigates whether the fine-gridded regional climate models are found to add value to the simulated mean and extreme daily and sub-daily precipitation compared to their coarser-gridded 0.44 degrees (similar to 50 km) counterparts. Therefore, pairs of fine-and coarse-gridded simulations of eight reanalysis-driven models are compared to fine-gridded observations in the Alps, Germany, Sweden, Norway, France, the Carpathians, and Spain. A clear result is that the 0.11 degrees simulations are found to better reproduce mean and extreme precipitation for almost all regions and seasons, even on the scale of the coarser-gridded simulations (50 km). This is primarily caused by the improved representation of orography in the 0.11 degrees simulations and therefore largest improvements can be found in regions with substantial orographic features. Improvements in reproducing precipitation in the summer season appear also due to the fact that in the fine-gridded simulations the larger scales of convection are captured by the resolved-scale dynamics. The 0.11 degrees simulations reduce biases in large areas of the investigated regions, have an improved representation of spatial precipitation patterns, and precipitation distributions are improved for daily and in particular for 3 hourly precipitation sums in Switzerland. When the evaluation is conducted on the fine (12.5 km) grid, the added value of the 0.11 degrees models becomes even more obvious.

  • 438. Klutse, Nana Ama Browne
    et al.
    Sylla, Mouhamadou Bamba
    Diallo, Ismaila
    Sarr, Abdoulaye
    Dosio, Alessandro
    Diedhiou, Arona
    Kamga, Andre
    Lamptey, Benjamin
    Ali, Abdou
    Gbobaniyi, Emiola O.
    Owusu, Kwadwo
    Lennard, Christopher
    Hewitson, Bruce
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Panitz, Hans-Juergen
    Buechner, Matthias
    Daily characteristics of West African summer monsoon precipitation in CORDEX simulations2016In: Journal of Theoretical and Applied Climatology, ISSN 0177-798X, E-ISSN 1434-4483, Vol. 123, no 1-2, p. 369-386Article in journal (Refereed)
    Abstract [en]

    We analyze and intercompare the performance of a set of ten regional climate models (RCMs) along with the ensemble mean of their statistics in simulating daily precipitation characteristics during the West African monsoon (WAM) period (June-July-August-September). The experiments are conducted within the framework of the COordinated Regional Downscaling Experiments for the African domain. We find that the RCMs exhibit substantial differences that are associated with a wide range of estimates of higher-order statistics, such as intensity, frequency, and daily extremes mostly driven by the convective scheme employed. For instance, a number of the RCMs simulate a similar number of wet days compared to observations but greater rainfall intensity, especially in oceanic regions adjacent to the Guinea Highlands because of a larger number of heavy precipitation events. Other models exhibit a higher wet-day frequency but much lower rainfall intensity over West Africa due to the occurrence of less frequent heavy rainfall events. This indicates the existence of large uncertainties related to the simulation of daily rainfall characteristics by the RCMs. The ensemble mean of the indices substantially improves the RCMs' simulated frequency and intensity of precipitation events, moderately outperforms that of the 95th percentile, and provides mixed benefits for the dry and wet spells. Although the ensemble mean improved results cannot be generalized, such an approach produces encouraging results and can help, to some extent, to improve the robustness of the response of the WAM daily precipitation to the anthropogenic greenhouse gas warming.

  • 439. Neset, Tina-Simone
    et al.
    Opach, Tomasz
    Lion, Peter
    Lilja, Anna
    SMHI.
    Johansson, Jimmy
    Map-Based Web Tools Supporting Climate Change Adaptation2016In: Professional Geographer, ISSN 0033-0124, E-ISSN 1467-9272, Vol. 68, no 1, p. 103-114Article in journal (Refereed)
    Abstract [en]

    This article discusses the state of the art in geovisualization supporting climate change adaptation. We reviewed twenty selected map-based Web tools, classified by their content and functionality, and assessed them by visual representations, interactive functions, information type, target audience, and how vulnerability and adaptation to climate change are addressed. Our study concludes that the tools (1) can be classified as data viewers with basic functionality and data explorers offering more sophisticated interactive functions; (2) mostly feature moderate or high richness of data content; and (3) predominantly target expert users.

  • 440.
    Koenigk, Torben
    et al.
    SMHI, Research Department, Climate research - Rossby Centre.
    Caian, Mihaela
    SMHI, Research Department, Climate research - Rossby Centre.
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Schimanke, Semjon
    SMHI, Research Department, Oceanography.
    Regional Arctic sea ice variations as predictor for winter climate conditions2016In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 46, no 1-2, p. 317-337Article in journal (Refereed)
    Abstract [en]

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

  • 441. Cerezo-Mota, Ruth
    et al.
    Cavazos, Tereza
    Arritt, Raymond
    Torres-Alavez, Abraham
    Sieck, Kevin
    Nikulin, Grigory
    SMHI, Research Department, Climate research - Rossby Centre.
    Moufouma-Okia, Wilfram
    Antonio Salinas-Prieto, Jose
    CORDEX-NA: factors inducing dry/wet years on the North American Monsoon region2016In: International Journal of Climatology, ISSN 0899-8418, E-ISSN 1097-0088, Vol. 36, no 2, p. 824-836Article in journal (Refereed)
    Abstract [en]

    The output of four regional climate models (RCMs) from the Coordinated Regional Climate Downscaling Experiment (CORDEX)-North America (NA) region was analysed for the 1990-2008 period, with particular interest on the mechanisms associated with wet and dry years over the North American Monsoon (NAM) core region. All RCMs (RCA3.5, HadGEM3-RA, REMO, and RegCM4) were forced by the ERA-Interim reanalysis. Model precipitation was compared against several observational gridded data sets at different time scales. Most RCMs capture well the annual cycle of precipitation and outperform ERA-Interim, which is drier than the observations. RCMs underestimate (overestimate) the precipitation over the coastal plains (mountains) and have some problems to reproduce the interannual variability of the monsoon. To further investigate this, two extreme summers that showed the largest consistency among observations and RCMs were chosen: one wet (1990) and one dry (2005). The impact of the passage of tropical cyclones, the size of the Western Hemisphere Warm Pool (WHWP), the Intertropical Convergence Zone (ITCZ) position, and the initial intensity of the land-sea thermal contrast (LSTC) were analysed. During the wet year, the LSTC was stronger than the 2005 dry monsoon season and there were a larger number of hurricanes near the Gulf of California, the WHWP was more extended, and the ITCZ was located in a more northerly position than in 2005. All these processes contributed to a wetter NAM season. During the dry year, the LSTC was weaker, with a later onset, probably due to a previous very wet winter. The inverse precipitation relationship between winter and summer in the monsoon region was well captured by most of the RCMs. RegCM4 showed the largest biases and HadGEM3-RA the smallest ones.

  • 442. Leroux, Stephanie
    et al.
    Bellon, Gilles
    Roehrig, Romain
    Caian, Mihaela
    SMHI, Research Department, Climate research - Rossby Centre.
    Klingaman, Nicholas P.
    Lafore, Jean-Philippe
    Musat, Ionela
    Rio, Catherine
    Tyteca, Sophie
    Inter-model comparison of subseasonal tropical variability in aquaplanet experiments: Effect of a warm pool2016In: Journal of Advances in Modeling Earth Systems, ISSN 1942-2466, Vol. 8, no 4, p. 1526-1551Article in journal (Refereed)
  • 443. Haarsma, Reindert J.
    et al.
    Roberts, Malcolm J.
    Vidale, Pier Luigi
    Senior, Catherine A.
    Bellucci, Alessio
    Bao, Qing
    Chang, Ping
    Corti, Susanna
    Fuckar, Neven S.
    Guemas, Virginie
    von Hardenberg, Jost
    Hazeleger, Wilco
    Kodama, Chihiro
    Koenigk, Torben
    SMHI, Research Department, Climate research - Rossby Centre.
    Leung, L. Ruby
    Lu, Jian
    Luo, Jing-Jia
    Mao, Jiafu
    Mizielinski, Matthew S.
    Mizuta, Ryo
    Nobre, Paulo
    Satoh, Masaki
    Scoccimarro, Enrico
    Semmler, Tido
    Small, Justin
    von Storch, Jin-Song
    High Resolution Model Intercomparison Project (HighResMIP v1.0) for CMIP62016In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 9, no 11, p. 4185-4208Article in journal (Refereed)
  • 444. Wang, Zhan
    et al.
    Belusic, Danijel
    SMHI, Research Department, Climate research - Rossby Centre.
    Huang, Yi
    Siems, Steven T.
    Manton, Michael J.
    Understanding Orographic Effects on Surface Observations at Macquarie Island2016In: Journal of Applied Meteorology and Climatology, ISSN 1558-8424, E-ISSN 1558-8432, Vol. 55, no 11, p. 2377-2395Article in journal (Refereed)
  • 445. Grote, Ruediger
    et al.
    Samson, Roeland
    Alonso, Rocio
    Amorim, Jorge Humberto
    SMHI, Research Department, Air quality.
    Carinanos, Paloma
    Churkina, Galina
    Fares, Silvano
    Le Thiec, Didier
    Niinemets, Ulo
    Mikkelsen, Teis Norgaard
    Paoletti, Elena
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    Functional traits of urban trees: air pollution mitigation potential2016In: Frontiers in Ecology and the Environment, ISSN 1540-9295, E-ISSN 1540-9309, Vol. 14, no 10, p. 543-550Article in journal (Refereed)
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    Notes on using the mesoscale wind farm parameterization of Fitch et al. (2012) in WRF2016In: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824, Vol. 19, no 9, p. 1757-1758Article in journal (Refereed)
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    WCRP COordinated Regional Downscaling EXperiment (CORDEX): a diagnostic MIP for CMIP62016In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 9, no 11, p. 4087-4095Article in journal (Refereed)
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    Impact of climate change on the production and transport of sea salt aerosol on European seas2016In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, no 20, p. 13081-13104Article in journal (Refereed)
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    Surface shear stress dependence of gas transfer velocity parameterizations using DNS2016In: Journal of Geophysical Research - Oceans, ISSN 2169-9275, E-ISSN 2169-9291, Vol. 121, no 10, p. 7369-7389Article in journal (Refereed)
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