Blar i forfatter "Karlsen, Stein Rune"

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    • Changes in Onset of Vegetation Growth on Svalbard, 2000–2020 

      Karlsen, Stein Rune; Elvebakk, Arve; Tømmervik, Hans; Belda, Santiago; Stendardi, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-15)
      The global temperature is increasing, and this is affecting the vegetation phenology in many parts of the world. The most prominent changes occur at northern latitudes such as our study area, which is Svalbard, located between 76300N and 80500N. A cloud-free time series of MODIS-NDVI data was processed. The dataset was interpolated to daily data during the 2000–2020 period with a 231.65 m pixel ...

    • Correction: Anderson, H.B. et al. Using Ordinary Digital Cameras in Place of Near-Infrared Sensors to Derive Vegetation Indices for Phenology Studies of High Arctic Vegetation. Remote Sens. 2016, 8, 847 

      Anderson, Helen; Nilsen, Lennart; Tømmervik, Hans; Karlsen, Stein Rune; Nagai, Shin; Cooper, Elisabeth J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-28)
      After the publication of the research paper by Anderson et al. [ 1 ], a reanalysis of the data showed that mistakes had been introduced in the calculation of the greenness indices and the filtering for outliers prior to the statistical analysis. The calculation of the 2G_RBi and Channel G% indices were the most affected, while the filtering of the data for outliers had inadvertently removed too ...

    • High seasonal overlap in habitat suitability in a nonmigratory High Arctic ungulate 

      Pedersen, Åshild Ønvik; Soininen, Eeva M; Hansen, Brage Bremset; Le Moullec, Mathilde; Loe, Leif Egil; Paulsen, I.M.G.; Eischeid, Isabell; Karlsen, Stein Rune; Ropstad, Erik; Stien, Audun; Tarroux, Arnaud; Tømmervik, Hans; Ravolainen, Virve (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-26)
      Understanding drivers of space use and habitat selection is essential for management and conservation, especially under rapid environmental change. Here, we develop summer and winter habitat suitability models for the endemic wild Svalbard reindeer (Rangifer tarandus platyrhynchus). The High Arctic Svalbard tundra is currently subject to the fastest temperature increases on Earth, and reindeer ...

    • Multi-Sensor Analysis of Snow Seasonality and a Preliminary Assessment of SAR Backscatter Sensitivity to Arctic Vegetation: Limits and Capabilities 

      Stendardi, Laura; Karlsen, Stein Rune; Malnes, Eirik; Nilsen, Lennart; Tømmervik, Hans; Cooper, Elisabeth J.; Notarnicola, Claudia (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-13)
      Snow melt timing and the last day of snow cover have a significant impact on vegetation phenology in the Svalbard archipelago. The aim of this study is to assess the seasonal variations of the snow using a multi-sensor approach and to analyze the sensitivity of the Synthetic Aperture Radar (SAR) backscatter to vegetation growth and soil moisture in an arctic environment. A combined approach using ...

    • 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; Peer reviewed, 2023-09-16)
      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 Chlorophyll Fluorescence (SIF) of high-Arctic tundra. This northernmost hyperspectral sensor is located within the footprint of a tower for long-term eddy covariance flux measurements ...

    • Outbreaks by canopy-feeding geometrid moth cause state-dependent shifts in understorey plant communities 

      Karlsen, Stein Rune; Jepsen, Jane Uhd; Odland, Arvid; Ims, Rolf Anker; Elvebakk, Arve (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The increased spread of insect outbreaks is among the most severe impacts of climate warming predicted for northern boreal forest ecosystems. Compound disturbances by insect herbivores can cause sharp transitions between vegetation states with implications for ecosystem productivity and climate feedbacks. By analysing vegetation plots prior to and immediately after a severe and widespread ...

    • 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; Peer reviewed, 2021-02-15)
      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, where researchers share technology, experience, and data, work together to close knowledge gaps, and decrease the environmental footprint of science. SIOS maintains and facilitates ...

    • Spatial and temporal variability in the onset of the growing season on svalbard, arctic Norway - Measured by MODIS-NDVI satellite data 

      Karlsen, Stein Rune; Elvebakk, Arve; Høgda, Kjell Arild; Grydeland, Tom (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)

    • Time-series of cloud-free sentinel-2 ndvi data used in mapping the onset of growth of central Spitsbergen, Svalbard 

      Karlsen, Stein Rune; Stendardi, Laura; Tømmervik, Hans; Nilsen, Lennart; Arntzen, Ingar; Cooper, Elisabeth J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-02)
      The Arctic is a region that is expected to experience a high increase in temperature. Changes in the timing of phenological phases, such as the onset of growth (as observed by remote sensing), is a sensitive bio-indicator of climate change. In this paper, the study area was the central part of Spitsbergen, Svalbard, located between 77.28°N and 78.44°N. The goals of this study were: (1) to prepare, ...

    • Using Ordinary Digital Cameras in Place of Near-Infrared Sensors to Derive Vegetation Indices for Phenology Studies of High Arctic Vegetation 

      Anderson, Helen; Nilsen, Lennart; Tømmervik, Hans; Karlsen, Stein Rune; Nagai, Shin; Cooper, Elisabeth J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      To remotely monitor vegetation at temporal and spatial resolutions unobtainable with satellite-based systems, near remote sensing systems must be employed. To this extent we used Normalized Difference Vegetation Index NDVI sensors and normal digital cameras to monitor the greenness of six different but common and widespread High Arctic plant species/groups (graminoid/Salix polaris; Cassiope tetragona; ...