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A compilation of snow cover datasets for Svalbard: A multi-sensor, multi-model study / Hannah Vickers in Remote sensing, vol 13 n°10 (May 2021)  

Public [article]  inRemote sensing > vol 13 n°10 (May 2021) . - n° 2002 Titre : A compilation of snow cover datasets for Svalbard: A multi-sensor, multi-model study Type de document : Article/Communication Auteurs : Hannah Vickers, Auteur ; Eirik Malnes, Auteur ; Ward van Pelt, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : n° 2002 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] données multicapteurs [Termes IGN] image à haute résolution [Termes IGN] image Sentinel-MSI [Termes IGN] image Terra-MODIS [Termes IGN] manteau neigeux [Termes IGN] modélisation [Termes IGN] Normalized Difference Snow Index [Termes IGN] série temporelle [Termes IGN] surveillance hydrologique [Termes IGN] Svalbard Résumé : (auteur) Reliable and accurate mapping of snow cover are essential in applications such as water resource management, hazard forecasting, calibration and validation of hydrological models and climate impact assessments. Optical remote sensing has been utilized as a tool for snow cover monitoring over the last several decades. However, consistent long-term monitoring of snow cover can be challenging due to differences in spatial resolution and retrieval algorithms of the different generations of satellite-based sensors. Snow models represent a complementary tool to remote sensing for snow cover monitoring, being able to fill in temporal and spatial data gaps where a lack of observations exist. This study utilized three optical remote sensing datasets and two snow models with overlapping periods of data coverage to investigate the similarities and discrepancies in snow cover estimates over Nordenskiöld Land in central Svalbard. High-resolution Sentinel-2 observations were utilized to calibrate a 20-year MODIS snow cover dataset that was subsequently used to correct snow cover fraction estimates made by the lower resolution AVHRR instrument and snow model datasets. A consistent overestimation of snow cover fraction by the lower resolution datasets was found, as well as estimates of the first snow-free day (FSFD) that were, on average, 10–15 days later when compared with the baseline MODIS estimates. Correction of the AVHRR time series produced a significantly slower decadal change in the land-averaged FSFD, indicating that caution should be exercised when interpreting climate-related trends from earlier lower resolution observations. Substantial differences in the dynamic characteristics of snow cover in early autumn were also present between the remote sensing and snow model datasets, which need to be investigated separately. This work demonstrates that the consistency of earlier low spatial resolution snow cover datasets can be improved by using current-day higher resolution datasets. Numéro de notice : A2021-438 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.3390/rs13102002 date de publication en ligne : 20/05/2021 En ligne : https://doi.org/10.3390/rs13102002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97822 [article]

Mapping seasonal agricultural land use types using deep learning on Sentinel-2 image time series / Misganu Debella-Gilo in Remote sensing, Vol 13 n° 2 (January-2 2021)  

Public [article]  inRemote sensing > Vol 13 n° 2 (January-2 2021) . - n° 289 Titre : Mapping seasonal agricultural land use types using deep learning on Sentinel-2 image time series Type de document : Article/Communication Auteurs : Misganu Debella-Gilo, Auteur ; Arnt Kristian Gjertsen, Auteur Année de publication : 2021 Article en page(s) : n° 289 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] apprentissage automatique [Termes IGN] carte agricole [Termes IGN] carte d'utilisation du sol [Termes IGN] classification par Perceptron multicouche [Termes IGN] classification par réseau neuronal convolutif [Termes IGN] image Sentinel-MSI [Termes IGN] Norvège [Termes IGN] série temporelle [Termes IGN] Soil Adjusted Vegetation Index [Termes IGN] surface cultivée [Termes IGN] utilisation du sol [Termes IGN] variation saisonnière Résumé : (auteur) The size and location of agricultural fields that are in active use and the type of use during the growing season are among the vital information that is needed for the careful planning and forecasting of agricultural production at national and regional scales. In areas where such data are not readily available, an independent seasonal monitoring method is needed. Remote sensing is a widely used tool to map land use types, although there are some limitations that can partly be circumvented by using, among others, multiple observations, careful feature selection and appropriate analysis methods. Here, we used Sentinel-2 satellite image time series (SITS) over the land area of Norway to map three agricultural land use classes: cereal crops, fodder crops (grass) and unused areas. The Multilayer Perceptron (MLP) and two variants of the Convolutional Neural Network (CNN), are implemented on SITS data of four different temporal resolutions. These enabled us to compare twelve model-dataset combinations to identify the model-dataset combination that results in the most accurate predictions. The CNN is implemented in the spectral and temporal dimensions instead of the conventional spatial dimension. Rather than using existing deep learning architectures, an autotuning procedure is implemented so that the model hyperparameters are empirically optimized during the training. The results obtained on held-out test data show that up to 94% overall accuracy and 90% Cohen’s Kappa can be obtained when the 2D CNN is applied on the SITS data with a temporal resolution of 7 days. This is closely followed by the 1D CNN on the same dataset. However, the latter performs better than the former in predicting data outside the training set. It is further observed that cereal is predicted with the highest accuracy, followed by grass. Predicting the unused areas has been found to be difficult as there is no distinct surface condition that is common for all unused areas. Numéro de notice : A2021-198 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.3390/rs13020289 date de publication en ligne : 15/01/2021 En ligne : https://doi.org/10.3390/rs13020289 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97149 [article]

Cadastral development in Norway: the need for improvement / Leiv Bjarte Mjøs in Survey review, vol 52 n° 375 (November 2020)  

Public [article]  inSurvey review > vol 52 n° 375 (November 2020) . - pp 473 - 484 Titre : Cadastral development in Norway: the need for improvement Type de document : Article/Communication Auteurs : Leiv Bjarte Mjøs, Auteur Année de publication : 2020 Article en page(s) : pp 473 - 484 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cadastre étranger [Termes IGN] cadastre ancien [Termes IGN] cartographie cadastrale [Termes IGN] droit fiscal [Termes IGN] historique [Termes IGN] Norvège [Termes IGN] photogrammétrie Résumé : (auteur) Cadastral systems provide important information for the public and private sectors. To understand the functions and impacts of a cadastral system one needs to understand its development. The Norwegian cadastral system has its origins in the 1600s and is defined as a German-style cadastral system. In the early 1800s, an economic survey was initiated in the kingdom of Denmark-Norway to modernise the tax cadastres. After the defeat in the Napoleonic wars, Norway entered into a union with Sweden in 1814 and the survey was stopped. Consequently, cadastral mapping would not be introduced in Norway until 1960, and at that time photogrammetric methods with poor quality control were used. Land subdivisions were undertaken by laymen until 1980. The paper describes cadastral development in Norway, challenges that have arisen and how they can be addressed. Measures to improve the system are proposed. Numéro de notice : A2020-685 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2019.1637094 date de publication en ligne : 05/07/2019 En ligne : https://doi.org/10.1080/00396265.2019.1637094 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96213 [article]

Increasing Cervidae populations have variable impacts on habitat suitability for threatened forest plant and lichen species / James D.M. Speed in Forest ecology and management, vol 473 ([01/10/2020])  

Public [article]  inForest ecology and management > vol 473 [01/10/2020] . - 10 p. Titre : Increasing Cervidae populations have variable impacts on habitat suitability for threatened forest plant and lichen species Type de document : Article/Communication Auteurs : James D.M. Speed, Auteur ; Gunnar Austrheim, Auteur ; Mika Bendiksby, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : 10 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Cervidae [Termes IGN] écosystème forestier [Termes IGN] flore forestière [Termes IGN] forêt boréale [Termes IGN] habitat forestier [Termes IGN] Norvège [Termes IGN] végétation [Vedettes matières IGN] Ecologie forestière Résumé : (auteur) Large herbivores play a key role in temperate and boreal forest ecosystems. Cervidae (deer) population densities and community structure have undergone drastic changes in many parts of the world over the past decades, often with deer populations increasing. Many studies show impacts of Cervidae on multiple ecosystem properties, including vegetation and biodiversity, at local spatial scales. At larger spatial scales, however, impacts of changing Cervidae populations on forest ecosystems are less known. Although both abiotic and biotic dimensions contribute to shaping species’ niches, abiotic variables are generally given prominence when modelling species habitats and ranges. This is despite biotic changes, including changes in trophic structure, being an important component of global environmental change. In this study, we examined the potential contribution of Cervidae densities to the habitat suitability for rare plant and lichen species across the temperate and boreal forests of Norway, where cervid densities have increased over the past 60 years. We also examined how these changes in herbivore communities may have shaped habitat suitability for rare lichens and plants and discuss the results in light of continuing shifts in herbivore assemblages. We ran habitat suitability models for 47 species of rare plants and lichens, which were selected based on herbivory reported as a criterion for placement on the national red list for species. Climate (temperature and precipitation), forest (forest type and productivity), soil pH and Cervidae densities (moose Alces alces, red deer Cervus elaphus and roe deer Capreolus capreolus) were used as independent variables. Densities of one or more of the three Cervidae species were inferred to be associated with the distribution of 14 (ten lichen, one bryophyte and three vascular plant species) of these 47 species. We found a range of habitat suitability associations with Cervidae densities, including positive, negative and hump-backed responses. Increases in Cervidae densities over the past 60 years may have led to different spatial trends in habitat suitability across the 14 species. Our results suggest that Cervidae densities are associated with the distribution of rare forest plant and lichen species differently at large spatial scales; experimental studies should test the causality of these associations. If causal, this implies that Cervidae management should find a balance between high and low densities to conserve several plant and lichen species. The preponderance of epiphytic lichens species, for which habitat suitability was associated with Cervidae densities, calls for field studies to focus on Cervidae impacts on forest lichens. Numéro de notice : A2020-622 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET Nature : Article DOI : 10.1016/j.foreco.2020.118286 date de publication en ligne : 20/06/2020 En ligne : https://doi.org/10.1016/j.foreco.2020.118286 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96018 [article]

A century of National Forest Inventory in Norway – informing past, present, and future decisions / Johannes Breidenbach in Forest ecosystems, vol 7 (2020)  

Public [article]  inForest ecosystems > vol 7 (2020) . - n° 46 Titre : A century of National Forest Inventory in Norway – informing past, present, and future decisions Type de document : Article/Communication Auteurs : Johannes Breidenbach, Auteur ; Aksel Granhus, Auteur ; Gro Hylen, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : n° 46 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] diamètre des arbres [Termes IGN] Norvège [Termes IGN] Pinophyta [Termes IGN] ressources forestières [Termes IGN] santé des forêts [Termes IGN] service écosystémique [Termes IGN] télédétection [Vedettes matières IGN] Inventaire forestier Résumé : (auteur) Past: In the early twentieth century, forestry was one of the most important sectors in Norway and an agitated discussion about the perceived decline of forest resources due to over-exploitation was ongoing. To base the discussion on facts, the young state of Norway established Landsskogtakseringen – the world’s first National Forest Inventory (NFI). Field work started in 1919 and was carried out by county. Trees were recorded on 10 m wide strips with 1–5 km interspaces. Site quality and land cover categories were recorded along each strip. Results for the first county were published in 1920, and by 1930 most forests below the coniferous tree line were inventoried. The 2nd to 5th inventories followed in the years 1937–1986. As of 1954, temporary sample plot clusters on a 3 km × 3 km grid were used as sampling units. Present: The current NFI grid was implemented in the 6th NFI from 1986 to 1993, when permanent plots on a 3 km × 3 km grid were established below the coniferous tree line. As of the 7th inventory in 1994, the NFI is continuous, and 1/5 of the plots are measured annually. All trees with a diameter ≥ 5 cm are recorded on circular, 250 m2 plots. The NFI grid was expanded in 2005 to cover alpine regions with 3 km × 9 km and 9 km × 9 km grids. In 2012, the NFI grid within forest reserves was doubled along the cardinal directions. Clustered temporary plots are used periodically to facilitate county-level estimates. As of today, more than 120 variables are recorded in the NFI including bilberry cover, drainage status, deadwood, and forest health. Land-use changes are monitored and trees outside forests are recorded. Future: Considerable research efforts towards the integration of remote sensing technologies enable the publication of the Norwegian Forest Resource Map since 2015, which is also used for small area estimation at the municipality level. On the analysis side, capacity and software for long term growth and yield prognosis are being developed. Furthermore, we foresee the inclusion of further variables for monitoring ecosystem services, and an increasing demand for mapped information. The relatively simple NFI design has proven to be a robust choice for satisfying steadily increasing information needs and concurrently providing consistent time series. Numéro de notice : A2020-813 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1186/s40663-020-00261-0 date de publication en ligne : 17/07/2020 En ligne : https://doi.org/10.1186/s40663-020-00261-0 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96986 [article]

Mapping forest age using National Forest Inventory, airborne laser scanning, and Sentinel-2 data / Johannes Schumacher in Forest ecosystems, vol 7 (2020)  

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Spatiotemporal variation in the relationship between boreal forest productivity proxies and climate data / Clémentine Ols in Dendrochronologia, vol 58 (December 2019)  

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Site and age-dependent responses of Picea abies growth to climate variability / Petr Čermák in European Journal of Forest Research, vol 138 n° 3 (June 2019)  

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Precise DEM extraction from Svalbard using 1936 high oblique imagery / Luc Girod in Geoscientific instrumentation methods and data systems, vol 7 n° 4 ([01/10/2018])    

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La propriété en 3D : état des lieux / Anonyme in Géomatique expert, n° 123 (juillet - août 2018)

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Effects of terrain slope and aspect on the error of ALS-based predictions of forest attributes / Non-répertorié in Forestry, an international journal of forest research, vol 91 n° 2 (April 2018)  

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Value of airborne laser scanning and digital aerial photogrammetry data in forest decision making / Annika S. Kangas in Silva fennica, vol 52 n° 1 ([01/02/2018])  

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Generating terrestrial glacier views from historic airphotos for comparison with contemporary ground photographs / Marion Holst (2018) 

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Digital aerial photogrammetry can efficiently support large-area forest inventories in Norway / Lars Johannes in Forestry, an international journal of forest research, vol 90 n° 5 (December 2017)  

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Enhanced MODIS atmospheric total water vapour content trends in response to Arctic amplification / Dunya Alraddawi in Atmosphere, vol 8 n° 12 (December 2017)  

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