Browsing Høstingsarkiver by Author "Tømmervik, Hans"

Now showing items 1-10 of 10

  • A distributed time-lapse camera network to track vegetation phenology with high temporal detail and at varying scales 
    Parmentier, Frans-Jan W.; Nilsen, Lennart; Tømmervik, Hans; Cooper, Elisabeth J. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Near-surface remote sensing techniques are essential monitoring tools to provide spatial and temporal resolutions beyond the capabilities of orbital methods. This high level of detail is especially helpful to monitor ...
  • Changes in winter warming events in the Nordic Arctic Region 
    Vikhamar-Schuler, Dagrun; Isaksen, Ketil; Haugen, Jan Erik; Tømmervik, Hans; Luks, Bartlomiej; Schuler, Thomas Vikhamar; Bjerke, Jarle W. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
    In recent years extreme winter warming events have been reported in arctic areas. These events are characterized as extraordinarily warm weather episodes, occasionally combined with intense rainfall, causing ecological ...
  • Complexity revealed in the greening of the Arctic 
    Myers-Smith, Isla H.; Kerby, Jeffrey T.; Phoenix, Gareth K.; Bjerke, Jarle W.; Epstein, Howard E.; Assmann, Jakob J.; John, Christian; Andreu-Hayles, Laia; Angers-Blondin, Sandra; Beck, Pieter S. A.; Berner, Logan T.; Bhatt, Uma S.; Bjorkman, Anne D.; Blok, Daan; Bryn, Anders; Christiansen, Casper Tai; Cornelissen, J. Hans C.; Cunliffe, Andrew M.; Elmendorf, Sarah C.; Forbes, Bruce C.; Goetz, Scott J.; Hollister, Robert D.; de Jong, Rogier; Loranty, Michael M.; Macias-Fauria, Marc; Maseyk, Kadmiel; Normand, Signe; Olofsson, Johan; Parker, Thomas C.; Parmentier, Frans-Jan W.; Post, Eric; Schaepman-Strub, Gabriela; Stordal, Frode; Sullivan, Patrick F.; Thomas, Haydn J.D.; Tømmervik, Hans; Treharne, Rachael; Tweedie, Craig E.; Walker, Donald A.; Wilmking, Martin; Wipf, Sonja (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2020)
    As the Arctic warms, vegetation is responding, and satellite measures indicate widespread greening at high latitudes. This ‘greening of the Arctic’ is among the world’s most important large-scale ecological responses to ...
  • Feasibility of active handheld NDVI sensors for monitoring of lichen ground cover 
    Erlandsson, Rasmus; Arneberg, Marit Klemetsen; Tømmervik, Hans; Finne, Eirik Aasmo; Nilsen, Lennart; Bjerke, Jarle W. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    Vegetation indices are corner stones in vegetation monitoring. However, previous field studies on lichens and NDVI have been based on passive sensors. Active handheld sensors, with their own light sources, enables high- ...
  • Five decades of terrestrial and freshwater research at Ny-Ålesund, Svalbard 
    Pedersen, Åshild Ønvik; Convey, P.; Newsham, Kevin K.; Mosbacher, Jesper Bruun; Fuglei, Eva; Ravolainen, Virve; Hansen, Brage Bremset; Jensen, Thomas Correll; Augusti, A.; Biersma, Elisabeth Mackteld; Cooper, Elisabeth J.; Coulson, S.J.; Gabrielsen, Geir W.; Gallet, Jean-Charles; Karsten, U.; Kristiansen, Silje Marie; Svenning, Mette Marianne; Tveit, Alexander; Uchida, M.; Baneschi, I.; Calizza, E.; Cannone, N.; de Goede, E.M.; Doveri, M.; Elster, J.; Giamberini, M.S.; Hayashi, K.; Lang, Simone; Lee, Y.K.; Nakatsubo, T.; Pasquali, V.; Paulsen, I.M.G.; Pedersen, Christina Alsvik; Peng, F.; Provenzale, A.; Pushkareva, E.; Sandström, C.A.M.; Sklet, Vera; Stach, A.; Tojo, M.; Tytgat, B.; Tømmervik, Hans; Velazquez, D.; Verleyen, E.; Welker, J.M.; Yao, Y.-F.; Loonen, M.J.J.E. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    For more than five decades, research has been conducted at Ny-Ålesund, in Svalbard, Norway, to understand the structure and functioning of High- Arctic ecosystems and the profound impacts on them of environmental change. ...
  • Rapid Ice‐Wedge Collapse and Permafrost Carbon Loss Triggered by Increased Snow Depth and Surface Runoff 
    Parmentier, Frans-Jan W.; Nilsen, Lennart; Tømmervik, Hans; Meisel, Ove H.; Bröder, Lisa; Vonk, Jorien E.; Westermann, Sebastian; Semenchuk, Phillip R.; Cooper, Elisabeth J. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
    Thicker snow cover in permafrost areas causes deeper active layers and thaw subsidence, which alter local hydrology and may amplify the loss of soil carbon. However, the potential for changes in snow cover and surface ...
  • SIOS’s Earth Observation (EO), Remote Sensing (RS), and operational activities in response to COVID-19 
    Jawak, Shridhar D.; Andersen, Bo N.; Pohjola, Veijo; Godøy, Øystein; Hübner, Christiane E.; Jennings, Inger; Ignatiuk, Dariusz; Holmen, Kim; Sivertsen, Agnar; Hann, Richard; Tømmervik, Hans; Kääb, Andreas; Błaszczyk, Małgorzata; Salzano, Roberto; Luks, Bartłomiej; Høgda, Kjell Arild; Storvold, Rune; Nilsen, Lennart; Salvatori, Rosamaria; Krishnan, Kottekkatu Padinchati; Chatterjee, Sourav; Lorentzen, Dag Arne; Erlandsson, Rasmus; Lauknes, Tom Rune; Malnes, Eirik; Karlsen, Stein Rune; Enomoto, Hiroyuki; Fjæraa, Ann Mari; Zhang, Jie; Marty, Sabine; Nygård, Knut Ove; Lihavainen, Heikki (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Svalbard Integrated Arctic Earth Observing System (SIOS) is an international partnership of research institutions studying the environment and climate in and around Svalbard. SIOS is developing an efficient observing system, ...
  • The northernmost hyperspectral FLoX sensor dataset for monitoring of high-Arctic tundra vegetation phenology and Sun-Induced Fluorescence (SIF) 
    Tømmervik, Hans; Julitta, Tommaso; Nilsen, Lennart; Park, Taejin; Burkart, Andreas; Ostapowicz, Katarzyna Anna; Karlsen, Stein Rune; Parmentier, Frans-Jan W.; Pirk, Norbert; Bjerke, Jarle W. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    A hyperspectral field sensor (FloX) was installed in Adventdalen (Svalbard, Norway) in 2019 as part of the Svalbard Integrated Arctic Earth Observing System (SIOS) for monitoring vegetation phenology and Sun-Induced ...
  • Variation in albedo and other vegetation characteristics in non-forested northern ecosystems: the role of lichens and mosses 
    Finne, Eirik Aasmo; Bjerke, Jarle W.; Erlandsson, Rasmus; Tømmervik, Hans; Stordal, Frode; Tallaksen, Lena M. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    Vegetation has a profound impact on climate through complex interactions and feedback loops, where especially regulation of albedo, the ratio of reflected to incoming solar radiation, is important at high latitudes. How ...
  • Vulnerability and resilience of the carbon exchange of a subarctic peatland to an extreme winter event 
    Parmentier, Frans-Jan; Rasse, Daniel P.; Lund, Magnus; Bjerke, Jarle W.; Drake, Bert G.; Weldon, Simon Mark; Tømmervik, Hans; Hansen, Georg Heinrich (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    Extreme winter events that damage vegetation are considered an important climatic cause of arctic browning—a reversal of the greening trend of the region—and possibly reduce the carbon uptake of northern ecosystems. ...