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  • 1.
    Dahlberg, Annika
    et al.
    Dept of Physical geography, Stockholm University.
    Borgström, Sara
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. Stockholms universitet, Stockholm Resilience Centre.
    Urbana gröna allmänningar för alla – eller inte? Tillgänglighet och mångfunktionalitet i en föränderlig stad2017In: Urban utveckling och interaktion / [ed] SSAG, Svenska sällskapet för Antropologi och Geografi, Stockholm: Svenska sällskapet för Antropologi och Geografi , 2017, p. 165-188Chapter in book (Other academic)
  • 2.
    Engström, Rebecka
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Howells, Mark I.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Destouni, Georgia
    Department of Physical Geography and the Bolin Centre of Climate Research, Stockholm University.
    Water impacts and water-climate goal conflicts of local energy choices – notes from a Swedish perspective2018In: Proceedings of the International Association of Hydrological Sciences, ISSN 2199-899X, Vol. 376, p. 25-33Article in journal (Refereed)
    Abstract [en]

    To meet both the Paris Agreement on Climate Change and the UN Sustainable Development Goals (SDGs), nations, sectors, counties and cities need to move towards a sustainable energy system in the next couple of decades. Such energy system transformations will impact water resources to varying extents, depending on the transformation strategy and fuel choices. Sweden is considered to be one of the most advanced countries towards meeting the SDGs. This paper explores the geographical origin of and the current water use associated with the supply of energy in the 21 regional counties of Sweden. These energy-related uses of water represent indirect, but still relevant, impacts for water management and the related SDG on clean water and sanitation (SDG 6). These indirect water impacts are here quantified and compared to reported quantifications of direct local water use, as well as to reported greenhouse gas (GHG) emissions, as one example of other types of environmental impacts of local energy choices in each county. For each county, an accounting model is set up based on data for the local energy use in year 2010, and the specific geographical origins and water use associated with these locally used energy carriers (fuels, heat and electricity) are further estimated and mapped based on data reported in the literature and open databases. Results show that most of the water use associated with the local Swedish energy use occurs outside of Sweden. Counties with large shares of liquid biofuel exhibit the largest associated indirect water use in regions outside of Sweden. This indirect water use for energy supply does not unambiguously correlate with either the local direct water use or the local GHG emissions, although for the latter, there is a tendency towards an inverse relation. Overall, the results imply that actions for mitigation of climate change by local energy choices may significantly affect water resources elsewhere. Swedish counties are thus important examples of localities with large geographic zones of water influence due to their local energy choices, which may compromise water security and the possibility to meet water-related global goals in other world regions.

  • 3.
    Jansson, Christer
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Urban microclimate and surface hydrometeorological processes2006Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The urban near surface atmosphere is of great concern since it affects the climate to which an increasing amount of people are immediately exposed. This study investigated the microclimate in central Stockholm in terms of the thermal conditions in the 0-2.5 m air layer and the water and heat exchange processes at different types of surfaces found within the urban environment. The main objective was to improve our understanding of the urban small-scale climate system.

    The urban microclimate was measured in terms of vertical air temperature profiles along a horizontal transect running through a vegetated park and its built-up surroundings during three clear and relatively calm summer days. The results showed that the air temperature at 1.2 m height within the park was 0.5 to 1.5 K lower than in the surrounding city blocks, and that the thermal stratification was generally stable (increasing temperature with height) in the park and unstable (decreasing temperature with height) in the built-up areas. In addition, there were a few examples of temperature gradients orientated in different directions within the lowest 2.5 m air layer, indicating horizontal advection between the park and the built-up areas. Climate conditions simulated with a three-dimensional microclimate model agreed well with observations and the model was therefore assumed to provide reasonable representations of important climate processes such as surface-air energy exchange processes. However, there were some discrepancies between observations and simulations that are discussed in terms of differences in real and modelled heat storage processes and wind conditions. Processes that need to be included for a more precise model description of areas such as the Stockholm environment include dynamic heat storage in buildings and dynamic wind forcing during the course of the simulation.

    A soil-vegetation-atmosphere transfer model was used to study soil water transport, the surface energy balance of an asphalt surface, and the impact of urban climate on evapotranspiration. Based on model calibration to field measurements of soil water content in a till catchment outside Stockholm, new parameter values were estimated that can be used for water flow modelling of till soils. The heat fluxes of an asphalt surface were reliably simulated without knowledge of site-specific calibration and the model was useful in identifying problems with energy balance closure based on measurements only. Simulations of ‘urban’ modifications to the forcing climate conditions demonstrated that increased air temperature, and thereby increased vapour pressure deficit, had most effect on evapotranspiration from tall vegetation, while increased long-wave radiation raised grass evapotranspiration the most.

  • 4.
    Jansson, Christer
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Espeby, Bengt
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Jansson, Per-Erik
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Preferential water flow in a glacial till soil2005In: Nordic Hydrology, ISSN 0029-1277, Vol. 36, no 1, p. 1-11Article in journal (Refereed)
    Abstract [en]

    Measured and simulated response of runoff during snowmelt has suggested that preferential water flow occurs as part of the infiltration process in glacial till. However, only a few quantitative studies have been presented. TDR measurements of soil water content were performed during the growing period in a till slope (7-10%) outside Stockholm. Soil cores were used to determine the water retention curve and the saturated hydraulic conductivity. A physically based one-dimensional model was used to simulate soil water dynamics in the slope. Two simulation approaches were used: a strict one-domain Darcian approach and a two-domain approach accounting for a bypass of the matrix flow system. The measured response of soil water content occurred within the first few hours after rainfall. This was best represented by the two-domain approach, while the response for the one-domain approach was significantly delayed with time and depth. The general behaviour of the soil water content throughout the season was, however, best simulated with a one-domain approach. The results indicated that preferential flow patterns through the unsaturated zone does not need to be considered to describe the seasonal pattern in glacial till soil. However, the results also point out that the purpose of the simulation is decisive when choosing a simulation approach, depending on whether the general soil water content over the season or the instant behaviour immediately after rainfall is of major interest.

  • 5. Jun, Chen
    et al.
    Ban, Yifang
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Li, Songnian
    China: Open access to Earth land-cover map2014In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 514, no 7523, p. 434-434Article in journal (Refereed)
  • 6. Lewis, Joshua A.
    et al.
    Zipperer, Wayne C.
    Ernstson, Henrik
    Philosophy and History, KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, History of Science, Technology and Environment. University of Manchester, UK.
    Bernik, Brittany
    Hazen, Rebecca
    Elmqvist, Thomas
    Blum, Michael J.
    Socioecological disparities in New Orleans following Hurricane Katrina2017In: Ecosphere, ISSN 2150-8925, E-ISSN 2150-8925, Vol. 8, no 9, article id e01922Article in journal (Refereed)
    Abstract [en]

    Despite growing interest in urban resilience, remarkably little is known about vegetation dynamics in the aftermath of disasters. In this study, we examined the composition and structure of plant communities across New Orleans (Louisiana, USA) following catastrophic flooding triggered by levee failures during Hurricane Katrina in 2005. Focusing on eight neighborhoods that span a range of demographic and topographical conditions, we assessed whether plant communities in post-Katrina New Orleans reflect flooding disturbance and post-disaster landscape management policies. We then contextualized vegetation patterns and associated ecosystem services and disservices with census-based demographic trends and indepth interviews to draw inferences about the drivers and outcomes of urban land abandonment in the aftermath of Hurricane Katrina. We found that areas subject to the greatest flooding disturbance exhibit the highest rates of vegetation response. Disturbance intensity and elevation, however, are relatively weak drivers of vegetation differences among the studied neighborhoods. Rather, we found that household income, racial demographics, and land abandonment are important drivers of vegetation community composition and structure across the city. Our findings indicate that resettlement and landscape management policies can mediate post-flooding ecological outcomes and demonstrate that unmanaged, emergent vegetation on abandoned lands can be an environmental justice concern in underserved and historically marginalized communities.

  • 7.
    Pechsiri, Joseph Santhi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Risén, Emma
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Malmström, Maria E.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Brandt, Nils
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Gröndahl, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Harvesting of Nodularia spumigena in the Baltic Sea: Assessment of Potentials and Added Benefits2014In: Journal of Coastal Research, ISSN 0749-0208, E-ISSN 1551-5036, Vol. 30, no 4, p. 825-831Article in journal (Refereed)
    Abstract [en]

    Interest to harvest wild cyanobacteria exists due to the environmental and socioeconomic risks during cyanobacteria blooms coupled with demands for nonterrestrial-based alternatives for biofuel sources. This research, therefore, sought to estimate the wild cyanobacteria harvesting potential using Nodularia spumigena, and using the Baltic Sea as the case study. Data from literature provided during years 2003-2009 were used to perform estimations. Additional benefits of harvesting were also assessed by estimating the nutrient removal and biogas production potentials from the harvested biomass. Results indicate that one boom unit has the potential to harvest approximately 3 to 700 kg dry weight of N. spumigena per hour depending on the algae concentration of the bloom. Results also suggest that nutrient removal and biogas production potentials provide substantial additional incentives to the harvesting operation during years of extensive and highly concentrated blooms. However, during nonextensive or nonconcentrated blooms such potentials are low.

  • 8. Piwowar, Joseph M.
    et al.
    Ban, Yifang
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Foreword to the Special Issue on the Analysis of Multitemporal Remote Sensing Images2014In: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, ISSN 1939-1404, E-ISSN 2151-1535, Vol. 7, no 8, p. 3187-3189Article in journal (Refereed)
  • 9.
    Riehm, Mats
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Nordin, Lina
    Optimization of winter road maintenance energy costs in Sweden: a critique of site specific frost warning techniques2012In: Meteorological Applications, ISSN 1350-4827, E-ISSN 1469-8080, Vol. 19, no 4, p. 443-453Article in journal (Refereed)
    Abstract [en]

    Frost formation on roads may cause slippery conditions and thereby increase the risk of accident occurrence. Roads are often treated with preventive operations using de-icing agents (e.g. road salt), which are ideally planned and performed prior to frost formation. The decisions on when and where to treat different road stretches with salt are based on meteorological measurements and forecasts. This paper investigates how uncertainties in meteorological measurements for frost prediction at road weather stations affect the efficiency of winter road maintenance. Different types of uncertainties and errors are discussed, together with potential solutions. The effects on winter road maintenance efficiency are discussed in terms of energy and cost. It was found that improvements in frost warning accuracy and reliability can lead to considerable savings and more efficient winter road maintenance.

  • 10. Yang, Jianyi
    et al.
    Tang, Guo'an
    Cao, Min
    Zhu, Rui
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment.
    An intelligent method to discover transition rules for cellular automata using bee colony optimisation2013In: International Journal of Geographical Information Science, ISSN 1365-8816, E-ISSN 1365-8824, Vol. 27, no 10, p. 1849-1864Article in journal (Refereed)
    Abstract [en]

    This paper presents a new, intelligent approach to discover transition rules for geographical cellular automata (CA) based on bee colony optimisation (BCO-CA) that can perform complex tasks through the cooperation and interaction of bees. The artificial bee colony miner algorithm is used to discover transition rules. In BCO-CA, a food source position is defined by its upper and lower thresholds for each attribute, and each bee searches the best upper and lower thresholds in each attribute as a zone. A transition rule is organised when the zone in each attribute is connected to another node by the operator And' and is linked to a cell status value. The transition rules are expressed by the logical structure statement IF-Then', which is explicit and easy to understand. Bee colony optimisation could better avoid the tendency to be vulnerable to local optimisation through local and global searching in the iterative process, and it does not require the discretisation of attribute values. Finally, The BCO-CA model is employed to simulate urban development in the Xi'an-Xian Yang urban area in China. Preliminary results suggest that this BCO approach is effective in capturing complex relationships between spatial variables and urban dynamics. Experimental results indicate that the BCO-CA model achieves a higher accuracy than the NULL and ACO-CA models, which demonstrates the feasibility and availability of the model in the simulation of complex urban dynamic change.

  • 11.
    Yousif, Osama
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Ban, Yifang
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Improving SAR-Based Urban Change Detection by Combining MAP-MRF Classifier and Nonlocal Means Similarity Weights2014In: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, ISSN 1939-1404, E-ISSN 2151-1535, Vol. 7, no 10, p. 4288-4300Article in journal (Refereed)
    Abstract [en]

    In remote sensing change detection, Markov random field (MRF) has been used successfully to model the prior probability using class-labels dependencies. MRF has played an important role in the detection of complex urban changes using optical images. However, the preservation of details in urban change analysis turns out to be a highly complex task if multi-temporal SAR images with their speckle are to be used. Here, the ability of MRF to preserve geometric details and to combat speckle effect at the same time becomes questionable. Blob-region phenomenon and fine structures removal are common consequences of the application of traditional MRF-based change detection algorithm. To overcome these limitations, the iterated conditional modes (ICM) framework for the optimization of the maximum a posteriori (MAP-MRF) criterion function is extended to include a nonlocal probability maximization step. This probability model, which characterizes the relationship between pixels' class-labels in a nonlocal scale, has the potential to preserve spatial details and to reduce speckle effects. Two multitemporal SAR datasets were used to assess the proposed algorithm. Experimental results using three density functions [i.e., the log normal (LN), generalized Gaussian (GG), and normal distributions (ND)] have demonstrated the efficiency of the proposed approach in terms of detail preservation and noise suppression. Compared with the traditional MRF algorithm, the proposed approach proved to be less-sensitive to the value of the contextual parameter and the chosen density function. The proposed approach has also shown less sensitivity to the quality of the initial change map when compared with the ICM algorithm.

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