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  • 151.
    Borgmark, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Physical parameters and accumulation rates in peat in relation to the climate during the last 150 years2006Rapport (Annet vitenskapelig)
  • 152.
    Borgmark, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    The colour of climate: A study of raised bogs in south-central Sweden2005Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis focuses on responses in raised bogs to changes in the effective humidity during the Holocene. Raised bogs are terrestrial deposits that can provide contiguous records of past climate changes. Information on and knowledge about past changes in climate is crucial for our understanding of natural climate variability. Analyses on different spatial and temporal scales have been conducted on a number of raised bogs in south-central Sweden in order to gain more knowledge about Holocene climate variability.

    Peatlands are useful as palaeoenvironmental archives because they develop over the course of millennia and provide a multi-faceted contiguous outlook on the past. Peat humification, a proxy for bog surface wetness, has been used to reconstruct palaeoclimate. In addition measurements of carbon and nitrogen on sub-recent peat from two bogs have been performed. The chronologies have been constrained by AMS radiocarbon dates and tephrochronology and by SCPs for the sub-recent peat.

    A comparison between a peat humification record from Värmland, south-central Sweden, and a dendrochronological record from Jämtland, north-central Sweden, indicates several synchronous changes between drier and wetter climate. This implies that changes in hydrology operate on a regional scale.

    In a high resolution study of two bogs in Uppland, south-central Sweden, C, N and peat humification have been compared to bog water tables inferred from testate amoebae and with meteorological data covering the last 150 years. The results indicate that peat can be subjected to secondary decomposition, resulting in an apparent lead in peat humification and C/N compared to biological proxies and meteorological data.

    Several periods of wetter conditions are indicated from the analysis of five peat sequences from three bogs in Värmland. Wetter conditions around especially c. 4500, 3500, 2800 and 1700-1000 cal yr BP can be correlated to several other climate records across the North Atlantic region and Scandinavia, indicating wetter and/or cooler climatic conditions at these times. Frequency analyses of two bogs indicate periodicities between 200 and 400 years that may be caused by cycles in solar activity.

  • 153.
    Borgmark, Anders
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Schoning, Kristian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    A comparative study of peat proxies from two eastern central Swedish bogs and their relation to meteorological data2006Inngår i: Journal of Quaternary Science, ISSN 0267-8179, E-ISSN 1099-1417, Vol. 21, nr 2, s. 109-114Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Analyses of peat humification, testate amoebae, carbon and nitrogen content have been carried out on a peat sequence from Ältabergsmossen. At Gullbergbymossen testate amoebae and peat humification were analysed. Both bogs are located in eastern central Sweden. The longest sequence, Ältabergsmossen, covers the last 150 yr and the data from Gullbergbymossen covers the last 60 yr, both with a time resolution of ca. 2–4 yr cm−1. The different proxies were compared to each other and were also compared to instrumental meteorological data. Correlation between peat humification and C/N ratios is high whereas the correlation is low between these physical/chemical parameters and reconstructed water tables inferred from the testate amoebae assemblages. High peat humification values and C/N ratios greater than 50 indicate aerobic decay and are thought to reflect the thickness of the acrotelm. High humification values and low C/N ratios are recorded in peat deposited between 1965 and 1980, whereas the dry period starts in the early 1970s according to instrumental meteorological data and inferred water-table depth. The difference in the timing of the onset of a dry-shift between the physical/chemical proxies and meteorological data and testate amoebae derived water table changes is interpreted as renewed decay of already deposited peat. The term secondary decomposition is used for this process. The secondary decomposition process has implications for interpreting physical/chemical and biological parameters in peat as they may be out of phase during the beginning of a dry-shift.

  • 154.
    Borgmark, Anders
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi.
    Wastegård, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi.
    Regional and local patterns of peat humification in three raised bogs in Värmland, south-central Sweden2008Inngår i: GFF, Vol. 130, nr 161-176Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Peat humification in five cores from three ombrotrophic bogs in Värmland, south-central Sweden, was analysed in an attempt to investigate local and regional responses to climate changes during the Holocene. The chronology of the five peat sequences was constrained by means of AMS radiocarbon dates and tephrochronology. Four tephras were geochemically correlated with the Askja AD 1875, Hekla-3, Kebister and Hekla-4 tephras. A further tephra, the Stömyren tephra, dated by interpolation to 2200–2100 cal yr BP was found in one bog. A composite record of peat humification changes show several periods of wetter bog conditions. These occur during the later part of the Holocene, corresponding to known climate changes in the North Atlantic region, especially around 4500–4000, 3700–3200, 3000–2700 and 1700–700 cal yr BP. Wet shifts are inferred from individual peat cores and the composite record at c. 5500, 4200, 3700, 3500, 2900, 1700, 850, 650, 500 and 250 cal yr BP. Development of composite records could be a powerful tool to smooth the palaeohydrological records in order to reduce the influence of local fluctuations in the proxy data and to extract the regional climatic signal.

  • 155.
    Borgmark, Anders
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Wastegård, Stefan
    Regional and local patterns of peat ­humification in three raised peat bogs in Värmland, south-central SwedenManuskript (Annet vitenskapelig)
  • 156.
    Borgström, Sara
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Cousins, Sara
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Lindborg, Regina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Outside the boundary - land use changes in the surroundings of urban nature reserves2012Inngår i: Applied Geography, ISSN 0143-6228, E-ISSN 1873-7730, Vol. 32, nr 2, s. 350-359Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The importance of the landscape surrounding a protected area for sustaining its values is frequently discussed in conservation literature. Studies on the interactions of urbanisation and nature conservation at the global scale suggest that protected nature attracts urbanisation, and that this in turn might negatively impact the area. However, studies specifically addressing such land use dynamics at city scale are largely missing. In this study we examine the change in proportion of built up area in two zones (500 m and 1000 m) surrounding 15 urban nature reserves in southern Sweden. By using comprehensive maps from the last 50 years, we compared the zones to the overall urbanisation in the cities to reveal discrepancies in land use surrounding the nature reserves. We found that the amount of built up area in the buffer zones surrounding nature reserves followed the same trend as the corresponding cities and this relation was stable over time, although the positive relationship was not significant. The establishment of nature reserves had no detectable effect on surrounding land use, however two distinguished groups of reserves were identified with either more or less built up area in buffers zones compared to cities. These differences were related to specific local drivers such as land ownership, land use history and nature reserve location. In contrast to earlier studies at global scale, our study did not show that nature reserves attract urbanisation. Instead, we stress that the great variety of contextual factors at the city scale makes quantitative analysis of this kind extremely difficult. However, a general neglect from planning and nature conservation agencies to recognise nature reserves’ dependence on the surrounding landscape configuration could be detrimental to sustain their values in the long-term. Hence we suggest that zones surrounding nature-protected areas should be planned and managed according to local land use history and current landscape conditions to enable and enhance necessary cross-boundary interactions.

  • 157.
    Borgström, Sara
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Lindborg, Regina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Elmqvist, Thomas
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Nature conservation for what?: Analyses of urban and rural nature reserves in southern Sweden 1909-20062013Inngår i: Landscape and Urban Planning, ISSN 0169-2046, E-ISSN 1872-6062, Vol. 117, s. 66-80Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To effectively integrate nature conservation in sustainable landscape management, it isessential to deepen the understanding of why, what, where and for whom nature isprotected. This is especially important for nature conservation in human dominatedlandscapes such as cities, where the distance between built up and protected areas is inconstant decline due to urbanisation worldwide. In this study we use historical andcurrent data from Sweden to examine how urban compared to rural nature conservationhave been using formal nature reserve objectives. The focal nature conservationobjectives in our study area were preservation of biodiversity, restoration ofenvironments and outdoor recreation, as well as subdivision of those. The use of theseobjectives were analysed for 1869 nature reserves in relation to degree of urbanisation.We found that nature reserves in more urbanised landscapes were based on a highernumber of objectives. The urban reserves also had a different composition of objectives,where the objectives outdoor recreation and biodiversity preservation were morecommon in urban than in rural reserves. During the last decades we detected a shift inuse of objectives in urban areas, going from biodiversity preservation to a strongerfocus on outdoor recreation. National and global trends in the nature conservationdebate could also be seen as reflected in the use of objectives. To ensure its adaptivecapacity, we stress that urban nature conservation needs a more proactive strategy,where potential future social as well as ecological values must be embraced and notonly existing ones.

  • 158.
    Borén, Thomas
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Kulturgeografiska institutionen.
    Fridfeldt, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Kinlund, Peter
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Kulturgeografiska institutionen.
    Sannel, Britta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Introduction2007Inngår i: Geographical studies in Aotearoa 2006: report from a geographical field course in New Zealand, March 2006 / [ed] Thomas Borén, Stockholm: Kulturgeografiska inst. & Naturgeografiska inst., Stockholms universitet , 2007, , s. 1-4s. 1-4Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    A short introduction to the excursions and fieldwork that are part of the Advanced level Geography courses at Stockholm University. After the introduction follows seven bachelor theses in Geography, empirically based on fieldwork in Wanaka and Queenstown, New Zealand, March 2006.

  • 159.
    Borén, Thomas
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Kulturgeografiska institutionen.
    Fridfeldt, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Kinlund, Peter
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Kulturgeografiska institutionen.
    Sannel, Britta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Hultblad, Gertrud
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Geographical studies in Aotearoa 2006: Report from a geographical field course in New Zealand, March 2006.2007Rapport (Annet vitenskapelig)
    Abstract [sv]

    Rapporten innehåller sju stycken uppsatser av studenter på påbyggnadskursen (C-kursen) i Geografi vid Stockholms universitet. Samtliga uppsatser är baserade på eget fältarbete i Queenstown och Wanaka, Nya Zeeland, i mars 2006. Temat för uppsatserna varierar och de behandlar: urbana strukturer, platsidentitet, platskänsla, vingårdar och vinturism, ekoturism, äventyrsturism, samt migration mellan små städer. Uppsatserna föregås av en kort introduktion på engelska om geografiprogrammets exkursioner och fältkurser av Thomas Borén, Anders Fridfeldt, Peter Kinlund och Britta Sannel.

  • 160.
    Borén, Thomas
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Kulturgeografiska institutionen.
    Schlyter, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Beringia - en region?: Introduktion till en relationell regionalgeografi.2008Inngår i: Kring Beringia.: Expeditioner och folk., SSAG, Stockholm , 2008, s. 7-18Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [sv]

    Beringia - en region? är introduktionen till antologin Kring Beringia. Expeditioner och folk. Introduktionen behandlar regionbegreppet, relationella rum och sovjetisk geografi, samt sammanfattar kort de olika kapitelbidragen.

  • 161.
    Borén, Thomas
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Kulturgeografiska institutionen.
    Schlyter, PeterStockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Kring Beringia.: Expeditioner och folk.2008Collection/Antologi (Annet vitenskapelig)
    Abstract [sv]

    I Kring Beringia behandlar en internationell samling geografer och andra forskare och skribenter frågor om samhälle, miljö och resurser i Beringregionen, med tungdpunkt på den ryska delen.

    Kapitelförfattare är Thomas Borén och Peter Schlyter, Kristian Gerner, John Round, Jessica Graybill, Bente Eriksen, Elinor Andrén, Lada Lekai, Mikael Strandberg, samt Carl Johan Gurt.

  • 162. Bos, Johanna A. A.
    et al.
    Helmens, Karin F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Bohncke, Sjoerd J. P.
    Seppä, Heikki
    Birks, H. John B.
    Flora, vegetation and climate at Sokli, northeastern Fennoscandia, during the Weichselian Middle Pleniglacial2009Inngår i: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 38, nr 2, s. 335-348Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A 2 m thick laminated lacustrine deposit of silt and clay recovered from the high-latitudinal site at Sokli (northern Finland) provides a unique mid-Weichselian fossil record for Fennoscandia. High-resolution botanical and zoological analyses of the lacustrine deposit allow detailed reconstruction of the regional vegetational development and of the history of the lake and the wetland ecosystem within the Sokli basin during the early part of the Weichselian Middle Pleniglacial (=equivalent to Marine Isotope Stage (MIS) 3). The inferred terrestrial vegetation represented by the Sokli MIS 3 sequence (so-called Tulppio Interstadial) was probably low-arctic tundra, treeless but with shrub elements including juniper, willow, dwarf birch, ericoids, lycopods and a rich herb flora with a variety of arctic-alpine taxa and heliophilous, pioneer elements. The presence of herbs such as Rubus chamaemorus, Epilobium palustre, Potentilla palustris and Sphagnum, Drepanocladus and other mosses suggests that the lake was fringed by wet meadows and peatlands or peaty telmatic communities. The distributional ranges of pine and tree birch were probably only a few hundred kilometres south or southeast of Sokli. This is concordant with evidence for the presence of boreal tree taxa during the MIS 3 in the Baltic countries and further east in Europe, but contradicts with the commonly inferred treeless tundra or grass-dominated steppe conditions in central Europe.

  • 163.
    Bosson, Emma
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK). Swedish Nuclear Fuel and Waste Management Company, Stockholm, Sweden.
    Sabel, Ulrika
    Gustafsson, Lars-Göran
    Sassner, Mona
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Influences of shifts in climate, landscape, and permafrost on terrestrial hydrology2012Inngår i: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 117, artikkel-id D05120Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study has simulated the terrestrial hydrology associated with different climate, landscape, and permafrost regime scenarios for the field case example of the relatively well characterized coastal catchment of Forsmark, Sweden. The regime scenarios were selected from long-term simulation results of climate, topographical, shoreline, and associated Quaternary deposit and vegetation development in this catchment with a time perspective of 100,000 years or more and were used as drivers for hydrological simulations with the three-dimensional model MIKE SHE. The hydrological simulations quantify the responses of different water flow and water storage components of terrestrial hydrology to shifts from the present cool temperate climate landscape regime in Forsmark to a possible future Arctic periglacial landscape regime with or without permafrost. The results show complexity and nonlinearity in the runoff responses to precipitation changes due to parallel changes in evapotranspiration, along with changes in surface and subsurface water storage dynamics and flow pathways through the landscape. The results further illuminate different possible perspectives of what constitutes wetter/drier landscape conditions, in contrast to the clearer concept of what constitutes a warmer/colder climate.

  • 164.
    Bosson, Emma
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Selroos, Jan-Olof
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Stigsson, Martin
    Gustafsson, Lars-Göran
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Exchange and pathways of deep and shallow groundwater in different climate and permafrost conditions using the Forsmark site, Sweden, as an example catchment2012Inngår i: Hydrogeology Journal, ISSN 1431-2174, E-ISSN 1435-0157, Vol. 21, nr 1, s. 225-237Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study simulates and quantifies the exchange and the pathways of deep and shallow groundwaterflow and solute transport under different climate and permafrost conditions, considering the example field case of the coastal Forsmark catchment in Sweden. A number of simulation scenarios for different climate and permafrost condition combinations have been performed with the three-dimensional groundwater flow and transport model MIKE SHE. Results show generally decreasing vertical groundwater flow with depth, and smaller vertical flow under permafrost conditions than under unfrozen conditions. Also the overall pattern of both the vertical and the horizontal groundwater flow, and the water exchange between the deep and shallow groundwater systems, change dramatically in the presence of permafrost relative to unfrozen conditions. However, although the vertical groundwater flow decreases significantly in the presence of permafrost, there is still an exchange of water between the unfrozen groundwater system below the permafrost and the shallow groundwater in the active layer, via taliks. ‘Through taliks’ tend to prevail in areas that constitute groundwater discharge zones under unfrozen conditions, which then mostly shift to net recharge zones (through taliks with net downward flow) under permafrost conditions.

  • 165.
    Bovin, Mattias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Förutsättningar för skred i Huddinge kommun idag och i ett framtida klimat2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    It is imperative to provide more information regarding changed conditions resulting landslide events in a future climate. The aim of this thesis is to assess landslide susceptibility in Huddinge Municipality in middle Sweden. The main purpose is to produce a map, to visualize landslide susceptible areas, and to integrate the result with changes in physical factors such as climate change. Also, the thesis aims to analyze anthropogenic factors such as changes in land use and an increasing population in Huddinge Municipality. Methods used are GIS-analyses, interviews with staff of Huddinge Municipality, and field observations. The GIS-analysis solely aims to provide areas which are landslide susceptible in changed conditions in the future. Interviews with municipality employees provided data about population growth and future land use of Huddinge. In addition to the GIS analysis and the interviews, field observations and photo documentations were carried out to validate the GIS-results and to investigate if slopes in Huddinge are geomorphic active. It can be concluded that there are slopes in Huddinge Municipality which are landslide susceptible today and in a future climate. It can not be excluded that the landslide frequency will increase due to climate change because of increasing days with intense rainfall and fluctuations in the groundwater table. Most vulnerable areas are the ones located in areas which are both landslide susceptible, and where a growing population is predicted. In order to minimize the risk and vulnerability, Huddinge Municipality either cooperates with external companies or scientific institutions, or uses technical solutions to stabilize clay soils. Finally, the GIS-analysis used in this thesis in Huddinge Municipality is applicable to any other geographical areas in Sweden or elsewhere.

  • 166.
    Bovin, Mattias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Utveckling av biotopdatabas och tillämpning av landskapsekologisk analys i Huddinge kommun2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    På grund av ökad urbanisering och exploatering av grönområden i stadsnära miljöer fragmenteras och reduceras arters habitat vilket bland annat ligger till grund för den globalt minskade biologiska mångfalden. För att stärka och förbättra arters möjlighet till spridning i landskapet, och därmed säkra en hög biologisk mångfald, efterfrågas insamling av data och utveckling av nya metoder för att identifiera ekologiska kärnområden och för att analysera habitatnätverk. Syftet med den här studien är därför att 1) kartera och sammanställa biotoper i en biotopdatabas utifrån tolkning av infraröda flygbilder med digital stereofotogrammetri, 2) undersöka olika metoder att samla in data med hjälp av laser- och höjddata, och 3) att tillämpa landskapsekologisk analys på underlag i biotopkarteringen.

    Resultatet validerar att tolkning av infraröda flygbilder med digital stereofotogrammetri är en utmärkt källa för att kartera biotoper som medför en tolkningsnoggrannhet på 86 %. Valideringen av kateringen genomfördes med fältkontroller som utvärderades i felmatriser. En metod har även undersökts baserat på tidigare studier för att uppskatta busk- och krontäckning med hjälp av laserdata, men eftersom det saknas validering av resultatet bör den användas som en indikator för att visuellt uppskatta busk- och krontäckning i dagsläget. Fortsättningsvis har ett topografiskt fuktighetsindex (TWI) tillämpats med hjälp av höjddata för att uppskatta fuktighet i vegetationstäckta områden. Eftersom det saknas validering och tröskelvärden för att avgöra hur TWI ska klassificera olika fuktighetsgradienter, bör verktyget endast användas som en indikator för att visuellt uppskatta fuktighet tillsammans med tolkning av infraröda flygbilder. Om metoderna valideras med fältmätningar kan de bidra med att förbättra kvaliteten och tidseffektivisera kartering av biotoper.

    Biotopkarteringen fungerar som ett bra underlag vid tillämpning av landskapsekologisk analys. Med hjälp av MatrixGreen var det möjligt att modellera potentiella habitatnätverk för två olika arter inom studieområdet. På grund av en del problem med modelleringen i MatrixGreen bör resultaten beaktas med ett kritiskt angreppssätt, men kan eventuellt användas som ett underlag för framtida artinventeringar.

  • 167.
    Brandel, Malin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Representativitet av snödjup vid marktemperaturmätningar under snö för permafrostmodellering i området kring Tarfaladalen, norra Sverige2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Snö och permafrost är två interagerande komponenter i Kryosfären. Studien undersöker

    snödjupets representativitet vid marktemperaturmätningar under snötäcket (BTS) för

    identifiering av permafrost i Tarfala, norra Sverige. Snödjupsmätningar har utfördes i

    två korsande 20 m transekter i nordsydlig (NS) samt östvästlig (ÖV) riktning utifrån en

    BTS-punkt. Totalt har 37 BTS (snödjup > 80 cm) med tillhörande snödjupsmätningar

    registrerats och analyserats. Snödjupet varierar både lokalt kring mätpunkten och

    regionalt i mättransekter men är ändå ett representativt snödjup för en punkt.

    Representativa BTS, sett ur ett snödjupsperspektiv, bör registreras på platser med

    måttlig snödjupsvariation som på platser med homogent markunderlag, vindskyddade

    områden, lä bakom ryggar och sluttningar vinkelräta mot den dominerande

    vindriktningen.

    BTS provplatser bör också ta hänsyn till de mest förekommande klasserna av

    parametrarna altitud, sluttning och slutningsriktning för att erhålla representativa BTS.

    Detta baserat på jämförelse mellan två strategier för insamling av BTS genom

    permafrostmodellering mellan två dataset. Ett BTS dataset från 2011 jämfört med BTS

    insamlade mars 2013.

  • 168. Braun, Mattias
    et al.
    Schuler, Thomas
    Hock, Regine
    Brown, Ian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Jackson, Miriam
    Comparison of remote sensing derived glacier facies maps with distributed mass balance modelling at Engabreen, northern Norway.2007Inngår i: International Association of Hydrological Sciences: Red book series, nr 318, s. 126-134Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Abstract Calibration and validation of glacier mass balance models typically rely on mass balance data derived from measurements at individual points, often along altitudinal gradients, thus neglecting

    much of the spatial variability of mass balance. Remote sensing data can provide useful additional spatially distributed information, e.g. on surface conditions such as bare ice area, firn cover extent, or snow. We developed a semi-automated procedure to derive glacier-facies maps from Landsat satellite images, and applied it to Engabreen, an outlet glacier from the Svartisen ice cap in northern Norway. These maps, discriminating between firn, snow and ice surfaces, are then used as a reference for mass balance modelling. Facies information shows a general agreement with the available few field observations and results obtained by distributed mass balance modelling. We conclude that Earth Observation products provide a powerful, although as yet poorly exploited tool, for calibration and validation of distributed mass balance models.

  • 169. Breuer, L.
    et al.
    Huisman, J. A.
    Willems, P.
    Bormann, H.
    Bronstert, A.
    Croke, B. F. W.
    Frede, H. G.
    Graff, T.
    Hubrechts, L.
    Jakeman, A. J.
    Kite, G.
    Lanini, J.
    Leavesley, G.
    Lettenmaier, D. P.
    Lindstrom, G.
    Seibert, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Sivapalan, M.
    Viney, N. R.
    Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM). I: Model intercomparison with current land use2009Inngår i: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 32, nr 2, s. 129-146Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper introduces the project on 'Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM)' that aims at investigating the envelope of predictions on changes in hydrological fluxes due to land use change. As part of a series of four papers, this paper outlines the motivation and setup of LUCHEM, and presents a model intercomparison for the present-day simulation results. Such an intercomparison provides a valuable basis to investigate the effects of different model structures on model predictions and paves the ground for the analysis of the performance of multi-model ensembles and the reliability of the scenario predictions in companion papers. in this study, we applied a set of 10 lumped, semi-lumped and fully distributed hydrological models that have been previously used in land use change studies to the low mountainous Dill catchment. Germany. Substantial differences in model performance were observed with Nash-Sutcliffe efficiencies ranging from 0.53 to 0.92. Differences in model performance were attributed to (1) model input data, (2) model calibration and (3) the physical basis of the models. The models were applied with two sets of input data: an original and a homogenized data set. This homogenization of precipitation, temperature and leaf area index was performed to reduce the variation between the models. Homogenization improved the comparability of model simulations and resulted in a reduced average bias, although some variation in model data input remained. The effect of the physical differences between models on the long-term water balance was mainly attributed to differences in how models represent evapotranspiration. Semi-lumped and lumped conceptual models slightly outperformed the fully distributed and physically based models. This was attributed to the automatic model calibration typically used for this type of models. Overall, however, we conclude that there was no superior model if several measures of model performance are considered and that all models are suitable to participate in further multi-model ensemble set-ups and land use change scenario investigations.

  • 170. Briffa, KR
    et al.
    Schweingruber, FH
    Jones, PD
    Osborne, TJ
    Harris, IC
    Shiyatov, SG
    Vaganov, EA
    Grudd, H
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi.
    Trees tell of past climates: but are they speaking less clearly today?1998Inngår i: Philosophical Transactions of the Royal Society of London B, Vol. 353, s. 65-73Artikkel i tidsskrift (Fagfellevurdert)
  • 171. Briffa, KR
    et al.
    Shishov, VV
    Melvin, TM
    Vaganov, EA
    Grudd, H
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi.
    Hantemirov, RM
    Eronen, Matti
    Naurzbaev, MM
    Trends in recent temperature and radial tree growth spanning 2000 years across northwest Eurasia.2008Inngår i: Philos Trans R Soc Lond B Biol Sci, ISSN 0962-8436, Vol. 363, s. 2271-2284Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper describes variability in trends of annual tree growth at several locations in the high latitudes of Eurasia, providing a wide regional comparison over a 2000-year period. The study focuses on the nature of local and widespread tree-growth responses to recent warming seen in instrumental observations, available in northern regions for periods ranging from decades to a century. Instrumental temperature data demonstrate differences in seasonal scale of Eurasian warming and the complexity and spatial diversity of tree-growing-season trends in recent decades. A set of long tree-ring chronologies provides empirical evidence of association between inter-annual tree growth and local, primarily summer, temperature variability at each location. These data show no evidence of a recent breakdown in this association as has been found at other high-latitude Northern Hemisphere locations. Using Kendall's concordance, we quantify the time-dependent relationship between growth trends of the long chronologies as a group. This provides strong evidence that the extent of recent widespread warming across northwest Eurasia, with respect to 100- to 200-year trends, is unprecedented in the last 2000 years. An equivalent analysis of simulated temperatures using the HadCM3 model fails to show a similar increase in concordance expected as a consequence of anthropogenic forcing.

  • 172.
    Bring, Arvid
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Arctic Climate and Water Change: Information Relevance for Assessment and Adaptation2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The Arctic is subject to growing economic and political interest. Meanwhile, its water and climate systems are in rapid transformation. Relevant and accessible information about water and climate is therefore vital to detect, understand and adapt to the changes. This thesis investigates hydrological monitoring systems, climate model data, and our understanding of hydro-climatic change, for adaptation to water system changes in the Arctic. Results indicate a lack of harmonized water chemistry data, which may impede efforts to understand transport and origin of key waterborne constituents. Further development of monitoring cannot rely only on a reconciliation of observations and projections on where climate change will be the most severe, as they diverge in this regard. Climate model simulations of drainage basin temperature and precipitation have improved between two recent model generations, but large inaccuracies remain for precipitation projections. Late 20th-century discharge changes in major Arctic rivers generally show excess of water relative to precipitation changes. This indicates a possible contribution of stored water from permafrost or groundwater to sea level rise. The river contribution to the increasing Arctic Ocean freshwater inflow matches that of glaciers, which underlines the importance of considering all sources when assessing change. To provide adequate information for research and policy, Arctic hydrological and hydrochemical monitoring needs to be extended, better integrated and made more accessible. This especially applies to hydrochemistry monitoring, where a more complete set of monitored basins is motivated, including a general extension for the large unmonitored areas close to the Arctic Ocean. Improvements in climate model parameterizations are needed, in particular for precipitation projections. Finally, further water-focused data and modeling efforts are required to resolve the source of excess discharge in Arctic rivers.

  • 173.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Arctic Climate and Water Change: Model and Observation Relevance for Assessment and Adaptation2014Inngår i: Surveys in geophysics, ISSN 0169-3298, E-ISSN 1573-0956, Vol. 35, nr 3, s. 853-877Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The Arctic is subject to growing economic and political interest. Meanwhile, its climate and water systems are in rapid transformation. In this paper, we review and extend a set of studies on climate model results, hydro-climatic change, and hydrological monitoring systems. Results indicate that general circulation model (GCM) projections of drainage basin temperature and precipitation have improved between two model generations. However, some inaccuracies remain for precipitation projections. When considering geographical priorities for monitoring or adaptation efforts, our results indicate that future projections by GCMs and recent observations diverge regarding the basins where temperature and precipitation changes currently are the most pronounced and where they will be so in the future. Regarding late twentieth-century discharge changes in major Arctic rivers, data generally show excess of water relative to precipitation changes. This indicates a possible contribution to sea-level rise of river water that was previously stored in permafrost or groundwater. The river contribution to the increasing Arctic Ocean freshwater inflow is similar in magnitude to the separate contribution from glaciers, which underlines the importance of considering all possible sources of freshwater when assessing sea-level change. We further investigate monitoring systems and find a lack of harmonized water chemistry data, which limits the ability to understand the origin and transport of nutrients, carbon and sediment to the sea. To provide adequate information for research and policy, Arctic hydrological and hydrochemical monitoring needs to be extended, better integrated and made more accessible. Further water-focused data and modeling efforts are required to resolve the source of excess discharge in Arctic rivers. Finally, improvements in climate model parameterizations are needed, in particular for precipitation projections.

  • 174.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Divergent prioritization relevance of Arctic hydrological monitoring under climate change2012Konferansepaper (Annet vitenskapelig)
  • 175.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Divergent relevance and prioritization basis for hydro-climatic change monitoring in the Arctic2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Climate change affects society and the Earth System largely through water cycle changes, such as altered precipitation patterns and increased drought and flood pressures. In the Arctic, which undergoes a particularly large and rapid environmental transformation, information on water cycle changes is crucial to plan for societal adaptation. A prioritization strategy is then needed for how (where and when) monitoring should be focused to get the most relevant information and data on Arctic hydro-climatic change with limited available resources. We investigate different possible strategies for a geographic prioritization of hydro-climatic change monitoring in the Arctic. Results show conflicting prioritization basis across 14 major Arctic hydrological basins. The current monitoring density distribution is relevant for the so far observed but not for the projected future changes in Arctic climate. The present and the projected future hot-spots of greatest climate change differ, so that major spatial shifts must be anticipated in the future with regard to climate change severity across the Arctic. Important temporal shifts must further be anticipated in several major Arctic basins with currently decreasing but expected future increasing precipitation.

  • 176.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Evaluation of IPCC AR4 climate model performance over 14 major Arctic watershedsManuskript (preprint) (Annet vitenskapelig)
  • 177.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Hydro-climatic change indications of Arctic permafrost thawing2012Konferansepaper (Fagfellevurdert)
  • 178.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Hydro-climatic changes and their monitoring in the Arctic: Observation-model comparisons and prioritization options for monitoring development2013Inngår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 492, s. 273-280Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Arctic undergoes particularly large and rapid hydro-climatic changes, and information on hydrological responses to these changes is crucial to plan for societal adaptation. We investigate hydro-climatic change severity and monitoring in 14 major hydrological basins across the pan-Arctic, in view of different possible strategies for their monitoring prioritization. Results show that the current distribution of monitoring density in these basins is more relevant for so far observed precipitation changes than for observed temperature changes, or for projected future temperature and precipitation changes. Furthermore, present and projected future hot-spots of greatest hydro-climatic change differ spatially, so that major spatial shifts must occur in the future among the different Arctic basins in order for observations and climate model projections to converge with regard to hydro-climatic change severity. Also temporally, observation-model convergence requires that important change direction shifts occur in major Arctic basins, which have currently decreasing precipitation while model projections imply future increasing precipitation within them. Different prioritization options for rational development of hydro-climatic monitoring can be argued for based on the present results. The divergent prioritization options imply a need for an explicit strategy for achieving certain information goals, which must be selected from a larger set of different possible goals based on societal importance.

  • 179.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Hydrological and hydrochemical observation status in the pan-Arctic drainage basin2009Inngår i: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 28, s. 327-338Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to identify and understand the ongoing changes in the Arctic hydrological cycle, and the impacts on the Arctic Ocean, timely and open access to water and water-chemistry data is essential. By synthesizing and analysing all openly accessible water-discharge and water-quality data, we present an updated, quantitative picture of the status of observational data on hydrological and hydrochemical fluxes from the pan-Arctic drainage basin (PADB) to the ocean. We identify and compare the characteristics of monitored and unmonitored areas, and the differences between them, across the continents in the PADB. Results indicate significant gaps in monitoring data for water chemistry, in particular for high-latitude near-coastal areas. The differences in characteristics between monitored and unmonitored areas may bias assessments of hydrological and hydrochemical fluxes to the Arctic Ocean. The reliable identification and understanding of important biogeochemical processes in the PADB require extended monitoring, particularly in high-latitude permafrost ground, and more ready access to harmonized and integrated hydrochemical data.

  • 180.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Information relevance for scenarios of Arctic climate and water change2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Relevant and accessible information about Arctic water and climate change is vital for scenario projection and adaptation in the rapidly changing region. We investigate the adequacy and relevance of hydrological monitoring systems, climate model data and hydro-climatic change understanding for formulation of change scenarios and adaptation to water system changes in the Arctic. Our results indicate a lack of harmonized water chemistry data for the pan-Arctic drainage basin, which may impede efforts at understanding transport and origin of key waterborne constituents and projecting their changes of relevance for water, climate and ecosystems. Furthermore, divergent distribution of observed and projected climate change severity poses challenges to prioritizing monitoring development. Climate model projections of drainage basin temperature and precipitation have improved between two successive model generations, but large inaccuracies remain for projected precipitation scenarios. Late 20th-century discharge changes in major Arctic rivers generally show excess of water relative to observed precipitation changes, indicating a possible contribution of stored water from permafrost or groundwater, even when considering data uncertainty on Arctic precipitation. To provide adequate information for research and policy, Arctic hydrological and hydrochemical monitoring needs to be extended, better integrated and more accessible, specifically regarding hydrochemistry with a more complete set of basins, and in general for the large unmonitored areas closer to the Arctic Ocean. Improvements in climate model parameterizations are needed in particular for precipitation projections, and further water-focused data and modeling efforts are required to resolve the source of excess discharge in Arctic rivers. 

  • 181.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Relevance of Hydro-Climatic Change Projection and Monitoring for Assessment of Water Cycle Changes in the Arctic2011Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 40, nr 4, s. 316-369Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Rapid changes to the Arctic hydrological cycle challenge both our process understanding and our ability to find appropriate adaptation strategies. We have investigated the relevance and accuracy development of climate change projections for assessment of water cycle changes in major Arctic drainage basins. Results show relatively good agreement of climate model projections with observed temperature changes, but high model inaccuracy relative to available observation data for precipitation changes. Direct observations further show systematically larger (smaller) runoff than precipitation increases (decreases). This result is partly attributable to uncertainties and systematic bias in precipitation observations, but still indicates that some of the observed increase in Arctic river runoff is due to water storage changes, for example melting permafrost and/or groundwater storage changes, within the drainage basins. Such causes of runoff change affect sea level, in addition to ocean salinity, and inland water resources, ecosystems, and infrastructure. Process-based hydrological modeling and observations, which can resolve changes in evapotranspiration, and groundwater and permafrost storage at and below river basin scales, are needed in order to accurately interpret and translate climate-driven precipitation changes to changes in freshwater cycling and runoff. In contrast to this need, our results show that the density of Arctic runoff monitoring has become increasingly biased and less relevant by decreasing most and being lowest in river basins with the largest expected climatic changes.

  • 182.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Relevance of hydro-climatic change projection and monitoring for  assessment of water cycle changes in the Arctic2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Rapid changes to the Arctic hydrological cycle challenge both our process understanding and our ability to find appropriate adaptation strategies. We have investigated the relevance and accuracy development of climate change projections for assessment of water cycle changes in major Arctic drainage basins. Results show relatively good agreement of climate model projections with observed temperature changes, but high model inaccuracy relative to available observation data for precipitation changes. Direct observations further show systematically larger (smaller) runoff than precipitation increases (decreases). This result is partly attributable to uncertainties and systematic bias in precipitation observations, but still indicates that some of the observed increase in Arctic river runoff is due to water storage changes, for example melting permafrost and/or groundwater storage changes, within the drainage basins. Such causes of runoff change affect sea level, in addition to ocean salinity, and inland water resources, ecosystems and infrastructure. Process-based hydrological modeling and observations, which can resolve changes in evapotranspiration, and groundwater and permafrost storage at and below river basin scales, are needed in order to accurately interpret and translate climate-driven precipitation changes to changes in freshwater cycling and runoff. In contrast to this need, our results show that the density of Arctic runoff monitoring has become increasingly biased and less relevant by decreasing most and being lowest in river basins with the largest expected climatic changes.

  • 183.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Spatial patterns of decline in pan-arctic hydrological monitoring networks: a vulnerability map2008Inngår i: Northern Hydrology and its Global Role: XXV Nordic Hydrological Conference, 2008, s. 60-66Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The last decades of observed rapid and significant changes to the Arctic hydrological system indicate an ongoing transition to a state not previously observed in recent history, which stresses the need for hydrological and hydrochemical observation networks that are adequate for detecting, understanding and modeling these changes. Recent studies have reported a widespread decline in these networks, but little information is available on where the decline has been most critical, and how it relates to the distribution of socio-economic and climatic pressures on water resources in the pan-Arctic drainage basin. We present a quantitative picture of the spatial patterns of decline in Arctic hydrological monitoring networks. We also analyze which Arctic drainage basins that are left most vulnerable by this decline, due to their combination with socio-economic and climate pressures. Results indicate that for basins where the hydrological monitoring decline has been higher than average, population density and economic production intensity are also frequently above average. Furthermore, diverging spatial patterns in future modeled and recently observed temperature trends makes it difficult to determine the real vulnerability of these basins to temperature change pressures.

  • 184.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Hannerz, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Current status of Pan-Arctic hydrologic and hydrochemical observing networks2007Inngår i: Proceedings from the Arctic Coastal Zones at Risk workshop in Tromsö, Norway, 1-3 October 2007, 2007Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Access to reliable hydrologic and hydrochemical data is of paramount importance for accurately understanding and modeling ongoing change in the Arctic hydrologic cycle under a warming climate. Recent studies have shown that the availability of and accessibility to such data is limited, and also declining, for some Arctic areas. In particular, there is a lack of consistent monitoring of water chemistry. At the same time, there is little information on where and which data gaps are most critical.

    In light of the present decline of monitoring, it is important to compile and quantify the hydrological and water chemistry monitoring in the Arctic. It is further important to investigate whether there are any systematic differences in characteristics between monitored and unmonitored areas draining to the Arctic Ocean, as such biases might limit the ability of models to accurately predict hydrologic behavior across basins with different properties.

    We present a quantitative assessment of all openly available monitoring data for water discharge and important water chemistry parameters (carbon, nitrogen, phosphorus and sediment) in the pan-Arctic drainage basin.

    Openly accessible pan-Arctic monitoring data were assembled from various databases for discharge and water chemistry, and monitoring station locations were co-referenced to a 30-minute simulated topological network. This allowed the construction of a geographically distributed representation of the temporal and spatial extent of monitoring. By linking this information with spatially distributed basin properties, differences in characteristics between monitored and unmonitored areas were analyzed. Finally, spatial patterns in the recent decline of discharge monitoring were compared with recently observed and projected future temperature trends.

    Results indicate significant disparity in the spatial and temporal distribution of monitoring data, in particular for water chemistry monitoring, which is both spatially and temporally much less extensive than discharge monitoring. Additionally, there are systematic differences between the characteristics of monitored and unmonitored areas, within and between the different continents in the pan-Arctic drainage basin. The decline in network density has been greatest in four Eurasian basins. In these areas, recent observational temperature trends have been the smallest, while climate models predict the greatest future increases in these areas.

    The scarcity of water chemical data and the systematic differences in characteristics between monitored and unmonitored basins may limit the reliability of assessments of Arctic water and hydrochemical flux changes under a warming climate. Observed and modeled climate trends exhibit diverging spatial patterns, which makes it difficult to determine whether the basins with the greatest decline in discharge monitoring density are really the ones that will experience the greatest future temperature change. Arctic monitoring needs to be extended in certain areas to enable reliable characterization of hydrologic and hydro-chemical variability and change in the region.

  • 185.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Hannerz, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Pan-Arctic drainage basin monitoring: current status and potential significance for assessment of climate change effects and feedbacks2007Inngår i: Proceedings of the Third International Conference on Climate & Water, 2007, s. 88-93Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Access to reliable hydrologic data is of paramount importance for accurately understanding and modeling ongoing change in and climate feedbacks of the Arctic hydrologic cycle. The accessibility to such data is limited, and continues to decline for some Arctic areas, but there is little information on where and which data gaps are most critical. We present a quantitative assessment of openly accessible monitoring data for water discharge and chemistry in the pan-Arctic drainage basin. We also quantify differences in characteristics between monitored and unmonitored areas, and analyze spatial patterns in reported decline of discharge networks in relation to recently observed and future modeled temperature trends. Results indicate that there is significant disparity in the spatial and temporal distribution of monitoring data, in particular for water chemistry monitoring. Additionally, there are systematic differences between the characteristics of monitored and unmonitored areas, within and between the different continents in the pan-Arctic drainage basin. Discharge network density has declined the most in four Eurasian drainage basins, which show the smallest recently observed temperature trends but the greatest modeled future temperature changes. Differences in characteristics between monitored and unmonitored areas may limit the reliability of assessments of Arctic water and solute flux change under a warming climate. Arctic monitoring needs to be extended in certain areas to fully enable characterization of the hydrologic variability and change in the region.

  • 186.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Hannerz, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Pan-Arctic Drainage Basin Monitoring: Current Status and Potential Significance for Assessment of Climate Change Impacts and Feedbacks2007Inngår i: Arctic Forum Abstract Volume, 2007Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Access to reliable hydrologic data is of paramount importance for the accurate understanding of changes in the arctic hydrologic cycle, and is also vital to policymakers as a base for sound environmental decisions. Accessibility to such data is limited and continues to decline for some arctic areas, while little information exists on which data gaps are most critical. This study presents a quantitative assessment of openly available monitoring data for water discharge and chemistry in the pan-arctic drainage basin. Results indicate that there is significant disparity in the spatial and temporal distribution of accessible monitoring data, in particular for water chemistry monitoring. Additionally, there are systematic differences between the characteristics of monitored and unmonitored areas. These differences may limit the reliability of assessments of arctic water and solute flux changes under a warming climate. Arctic monitoring needs to be extended in certain areas, and data needs to be disseminated more efficiently, to fully enable characterization of the hydrologic variability and change in the region.

  • 187.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Hannerz, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Pan-Arctic drainage basin observation networks: current status and potential significance for assessment of climate change effects and feedbacks2007Inngår i: 1st IPY workshop on Sustaining Arctic Observing Networks, 2007Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Hydrological observation networks are integral for understanding and modeling present and future changes in and climate feedbacks to the Arctic environmental system. Recent studies have reported a widespread decline in these networks, but patterns of decline and location of critical data gaps are less certain. We present an updated and quantitative status of openly accessible observation network data for discharge and water chemistry in the pan-Arctic drainage area. We also compare relevant hydrological and socio-economic characteristics of monitored and unmonitored areas, and analyze the decline in network density in relation to recently observed and future modeled temperature trends. Results indicate that there are significant temporal and spatial variations in accessible data, and that there is a critical lack of accessible water chemistry data for large shares of the pan-Arctic. Furthermore, there are systematic differences in characteristics between monitored and unmonitored areas, within and between pan-Arctic regions. Discharge network density has declined the most in four Eurasian drainage basins, which show the smallest recently observed temperature trends but the greatest modeled future temperature changes. Differences in characteristics between monitored and unmonitored areas may limit the reliability of assessments of Arctic water and solute flux change under a warming climate. Improved understanding of the Arctic hydrological system requires less restricted access to monitoring data, extended network coverage of unmonitored areas, and a commitment to sustaining and improving existing networks.

  • 188.
    Bring, Arvid
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Jarsjö, Jerker
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Water Information and Water Security in the Arctic2015Inngår i: The New Arctic / [ed] B. Evengård, J. Nymand Larsen, Ø. Paasche, Springer, 2015, s. 225-238Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Water is common to many environmental changes that are currently observed in the Arctic. To manage environmental change, and related water security challenges that are rising in the Arctic, adequate water information and monitoring is critical. Although water information systems have been deteriorating in the Arctic, there are still opportunities to combine existing data to inform policy decisions on how to manage water security. Furthermore, implementing a set of water security indicators can help identify areas of concern within the region. However, accessible climate change information is not always relevant for the scales of policymaking. In addition, improved representation of water on land in climate models is needed to better inform adaptation.

  • 189. Bring, Arvid
    et al.
    Rogberg, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Variability in climate change simulations affects needed long-term riverine nutrient reductions for the Baltic Sea2015Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, s. 381-391Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Changes to runoff due to climate change may influence management of nutrient loading to the sea. Assuming unchanged river nutrient concentrations, we evaluate the effects of changing runoff on commitments to nutrient reductions under the Baltic Sea Action Plan. For several countries, climate projections point to large variability in load changes in relation to reduction targets. These changes either increase loads, making the target more difficult to reach, or decrease them, leading instead to a full achievement of the target. The impact of variability in climate projections varies with the size of the reduction target and is larger for countries with more limited commitments. In the end, a number of focused actions are needed to manage the effects of climate change on nutrient loads: reducing uncertainty in climate projections, deciding on frameworks to identify best performing models with respect to land surface hydrology, and increasing efforts at sustained monitoring of water flow changes.

  • 190. Brooks, P
    et al.
    Kostzrewski, J
    Troch, P
    Lyon, S
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Litvak, M
    Liu, F
    Vivoni, E
    McDowell, N
    McConnell, J
    Small, E
    A predictive framework for coupling Hydrology, Biogeochemistry, and Ecology2008Inngår i: Vol. 10, EGU2008-A-09502, 2008, 2008Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The coupling of hydrological, biogeochemical, and ecological processes at catchment to landscape scale results in observable patterns in ecosystem structure, the amount and chemistry of stream discharge, and landsurface-atmosphere exchanges of energy and biogeochemicals. All of these patterns result from the close coupling of water, energy, carbon, and nutrient cycling, yet rarely are both the vertical (landsurfaceatmosphere) and lateral (hydrological residence time and streamflow) exchanges associated with a particular ecosystem structure studied in concert. Our research attempts to bridge this gap by focusing on how ecosystem structure, specifically vegetation, mediates four-dimensional (X,Y,Z, and time) fluxes of water, carbon, and nutrients in semi-arid environments of the southwestern United States. Our generalized approach involves an iterative combination of measurement, modeling, and experimentation where process-level inferences drawn from one research activity are used to develop testable hypothesis for related efforts. Preliminary results have linked spatial variability in hydrologic residence time to seasonal variability in nutrient limitation; spatial and interannual variability in water source with carbon uptake and isotopic signature; vegetation controls on both snow water input and soil moisture; and the importance of alluvial aquifers in stream and river biogeochemistry.

  • 191.
    Brown, Ian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Polarimetric scattering from shallow firn and forests with snow cover2010Inngår i: Proceedings of the ESA Living Planet SymposiumBergen, Norway: (ESA SP-686, December 2010) / [ed] H. Lacoste-Francis, Noordwijk, Netherlands: European Space Agency , 2010Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In this paper the potential for inferring shallow firn depth from polarimetric SAR (PolSAR) data at L- and C-band is investigated. Using ALOS PALSAR and Radarsat-2 SAR imagery, and field data including Ground Penetrating Radar profiles and shallow cores, we investigate the spatial distribution of backscatter and decompose backscatter using polarimetric methods to analyse how polarimetric scattering is affected by firn depth near the firn line. The investigation is aimed at a more refined delineation of glacier firn lines and a better understanding of scattering from firn, superimposed ice and the bare ice facies. We found that PolSAR can be used to infer shallow firn thicknesses up to depths of at least 2 m water equivalent (m w.e.) and that old and contemporary firn surfaces can be differentiated using PolSAR. Contrary to many previous investigations the importance of surface scattering in the firn area is also emphasised in the scattering decompositions. Volume scattering was found to have a secondary or tertiary importance. This has important implications for the analysis of backscatter using semi-empirical models.The effect of snow depth on backscatter in pro-glacial a sub-Arctic forest and its potential for improving forest mapping is also discussed. Snow depth data were acquired by manual probing and snowpit measurements. In addition forest stand densities were assessed in situ and NDVI and tasseled cap transformations were made in optical remote sensing data (SPOT-4) to parameterise the forest. Scatterer decomposition and pedestal height products were found to be related to snowpack depth. It was not possible to separate the influences of snow cover and forest structure due to the partial dependence of the former on the latter. Nevertheless it can be concluded that PolSAR improves our ability to map the forest margins of low density, sub-Arctic forests. Our findings have implications for the implementation of algorithms for the exploitation of future SAR missions including Sentinel-1.

  • 192.
    Brown, Ian A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Assessing eco-scarcity as a cause of the outbreak of conflict in Darfur: a remote sensing approach2010Inngår i: International Journal of Remote Sensing, ISSN 0143-1161, E-ISSN 1366-5901, Vol. 31, nr 10, s. 2513-2520Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The conflict in Darfur, Western Sudan, is frequently represented in the media as a dispute over access to resources by competing communities. Environmental degradation is often cited as either a causal or a contributory factor to the outbreak of the conflict and its prolongation. In this paper, Normalized Difference Vegetation Index (NDVI) data are used as a measure of 'eco-scarcity' to assess the notion that the outbreak of conflict was the result of competition for resources between communities. It is shown that there is no evidence in the vegetation mapping for a worsening of the ecological situation in Western and Northern Darfur states around the outbreak of the conflict. On the contrary, the years prior to the outbreak of the conflict experienced better than average vegetation growth in the context of the past 25 years.

  • 193.
    Brown, Ian A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Synthetic Aperture Radar Measurements of a Retreating Firn Line on a Temperate Icecap2012Inngår i: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, ISSN 1939-1404, E-ISSN 2151-1535, Vol. 5, nr 1, s. 153-160Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The firn line, like other glacier facies, is mapped operationally as part of glacier monitoring activities for glaciological and climate studies. Synthetic aperture radar (SAR) images are commonly used to determine the firn line in dry snow imagery. The radiometric response of retreating firn has not previously been investigated. Rather, it has been assumed that firn line mapping is only useful where large scale advances or retreats of the lower limit of continuous firn have occurred. In this paper the radiometric signal of retreating firn on an icecap in north Norway is analyzed using multi-temporal SAR imagery. Using comparisons with firn well above the firn line and field investigations of the firn properties, backscattering mechanisms are inferred. It is found that retreating firn has a distinctive radiometric signal that can be used to identify the inception and progression of firn down-wasting prior to and during firn line retreat.

  • 194.
    Brown, Ian A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Ingvander, Susanne
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Spatial and temporal variations in Antarctic snow particle size identified in AMSR-E 89 GHz dataManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Here we use in situ observations to identify spatio-temporal variations of snow particle size in 89 GHz AMSR-E passive microwave satellite imagery. We have correlated high temporal resolution data daily AMSR-E with reference to high spatial resolution Envisat ASAR images to a validation dataset of snow particle size acquired during the Japanese Swedish Antarctic Expedition (JASE) 2007/2008. We have found strong correlations between the 89 GHz AMSR-E data and two different size parameters: particle length and estimated Specific Surface Area (SSA). These correlations have been used to model the grain size variations over the entire region of interest. The daily AMSR-E data have been used to study the evolution of the snowpack over time revealing a seasonal metamorphosis of snow particles at the coast that is largely absent on the polar plateau. Furthermore, the AMSR-E data may exhibit effects from the passing of coastal weather systems on 3-6 day cycles. These effects penetrate to the polar plateau and may represent the drainage of cold air from the plateau drawn-down by passing coastal weather systems.

  • 195.
    Brown, Ian
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Jackson, MiriamBraun, MattiasEngeset, Rune
    The correlation of glacier mass balance and SAR backscatter on Svartisen,Norway.2007Konferanseproceedings (Fagfellevurdert)
  • 196.
    Brown, Ian
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi.
    Sandgren, Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi.
    Investigation of the spatial variations in Synthetic Aperture Radar backscatter in western Dronning Maud Land, Antarctica2008Inngår i: Journal of Applied Remote Sensing, Vol. 2, nr 023509Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    C-band SAR observations show that backscatter varies significantly across small scales (tens of kilometers) in western Dronning Maud Land. Generally, backscatter was found to diminish with altitude reflecting lower accumulation and reduced ice inclusions in the firn of the percolation zone at higher elevations. Reference to (incomplete) mass balance data suggests an anticorrelation between backscatter and net balance, although more data are needed to confirm the trend. Even within the percolation zone, areas of low backscatter (<-12 dB) exist. These are uncorrelated with altitude above sea level. Using a Rayleigh backscatter model, we show that backscatter over such regions may represent differences in grain sizes. The application of a buried-layers model did not accurately estimate backscatter from these regions. We suggest that these regions occupy exposed positions subject to increased wind sublimation which, in turn, results in smaller grain sizes in the firn and therefore reduced backscatter. The Radarsat Antarctica Mapping Mission SAR mosaic indicates such regions occur in Coates Land, near the edge of the Antarctic Plateau, and on exposed promontories elsewhere in East Antarctica. More information regarding the structure of the firn and the mass balance of the region is needed before we can definitively explain controls on backscatter and understand the climatology of the low backscatter zones.

  • 197. Broxton, P
    et al.
    Troch, P
    Lyon, S
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    On the role of aspect to quantify water transit times in small mountainous catchments2009Inngår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 45, s. W08427-W08427Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the current empirical study, we provide evidence about how the hydrologic responses of small mountain catchments are related to aspect (slope direction; exposure) at Redondo Peak, located in the Valles Caldera, New Mexico, USA. Specifically, we test the hypothesis that the transit time of water is related to the catchment aspect. Aspect is an easily measurable and transferable topographic characteristic that is related to the amount of direct solar radiation a particular catchment receives, and therefore, different catchments with different aspects have different rates of snow ablation, evapotranspiration, and water cycling in general. Transit times, which describe the time between when water enters the catchment as precipitation and when it leaves as stream flow, captures many hydrologic features such as flowpath variability and the combined effects of water storage and water fluxes. We have designed an experiment that involves field data collection, isotopic analysis of stream and precipitation samples, and the estimation of transit times using lumped-parameter convolution for 15 sites in small (1-15 km2) catchments that drain different aspects of Redondo Peak. Our data suggests that isotopic variability and estimated transit times are both related to aspect. Other potential relationships between topographical features (such as flowpath length, slope gradient, and elevation) and isotopic measurements of streamwater suggest that landscape and hydrological features are interconnected at Redondo Peak, but these links are not conclusive, suggesting that these topographic indicators do not fully explain the variability of water cycling in these small mountain catchments.

  • 198. Bruce, Åke
    et al.
    Ihse, Margareta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Vegetationsrutorna på Enaforsholm2012Inngår i: Vid fjällets fot: donatorn A.W. Bergsten och hans Enaforsholm i Västjämtland - från jaktvilla till fjällgård / [ed] Hans Antonsson, Stockholm: Kungl. skogs- och lantbruksakademien , 2012, s. 251-260Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 199. Brunet, Manola
    et al.
    Jones, Philip D.
    Sigró, Javier
    Saladié, Oscar
    Aguilar, Enric
    Moberg, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi.
    Della-Marta, Paul M.
    Lister, David
    Walther, Alexander
    López, Diego
    Temporal and spatial temperature variability and change over Spain during 1850-20052007Inngår i: Journal of Gephysical Research: Atmospheres, Vol. 112, nr D12117Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We analyze temporal and spatial patterns of temperature change over Spain during the period 1850–2005, using daily maximum (T max), minimum (T min), and mean (T mean) temperatures from the 22 longest and most reliable Spanish records. Over mainland Spain, a significant (at 0.01 level) warming of 0.10°C/decade is found for the annual average of T mean. Autumn and winter contributed slightly more than spring and summer to the annual warming over the 1850–2005 period. The overall warming is also associated with higher rates of change for T max than T min (0.11° versus 0.08°C/decade for 1850–2005). This asymmetric diurnal warming increased in the twentieth century (0.17° versus 0.09°C/decade during 1901–2005). Nevertheless, at many (few) individual stations, the difference between T max and T min is not statistically significant over 1850–2005 (1901–2005). Principal Component Analysis has been carried out to identify spatial modes of Spanish long-term temperature variability (1901–2005). Three principal spatial patterns are found, Northern Spain, Southeastern and Eastern Spain, and Southwestern Spain. All three patterns show similar significant warming trends. The overall warming has been more associated with reductions in cold extremes, as opposed to increases in warm extremes. Estimated trends in the number of moderately extreme cold days (T max < 10th percentile) and moderately extreme cold nights (T min < 10th percentile) show significant reductions of 0.74 and 0.54 days/decade, respectively, over 1850–2005. Moderately extreme warm days and nights (T max and T min > 90th percentile) increased significantly but at lower rates of 0.53 and 0.49 days/decade.

  • 200. Brunet, Manola
    et al.
    Saladié, Oscar
    Jones, Phil
    Sigró, Javier
    Aguilar, Enric
    Moberg, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Lister, David
    Walther, Alexander
    Almarza, Carlos
    A case-study/guidance on the development of long-term daily adjusted temperature datasets: Climate Data and Monitoring WCDMP-No. 662008Rapport (Annet vitenskapelig)
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