| 1. |
- Gilichinsky, Michael, et al.
(författare)
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Application of national forest inventory for remote sensing classification of ground lichen in nothern Sweden
- 2010
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Ingår i: ISPRS Archives. - : International Society for Photogrammetry and Remote Sensing. ; 38-4-8, s. 146-152
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Konferensbidrag (refereegranskat)abstract
- Lichen is a major forage resource for reindeer and may constitute up to 80% of a reindeer's winter diet. The reindeer grazing area in Sweden covers almost half of the country, with reindeer using mountainous areas in the summer and forested areas in the winter. Knowledge about the spatial distribution of ground lichens is important for both practical and sustainable decisionmaking purposes. Since the early 1980s, remote sensing research of lichen cover in northern environments has focused on reindeer grazing issues. The objective of the present study was to use lichen information from the Swedish Forest Inventory (NFI) for classification of satellite data into ground lichen classes. The classification procedure was focused on using of NFI plots as training sets for supervised classification of the ground lichen cover in purpose to classify areas with different lichen coverage. The present research has shown the advantage of use forest inventory plot data by assessment of three methods: mahalanobis distance (MD) classification, maximum likelihood (ML) classification and spectral mixture analysis (SMA). The results of this study demonstrate high classification accuracy of SPOT imagery in distinction between lichenabundant and lichen-poor areas by mahalanobis distance classifier (overall accuracy 84.3%, kappa=0.68). The highest classification accuracy for Landsat scene was achieved by maximumlikelihood classification (overall accuracy 76.8%, kappa=0.53). The continuation research on more detailed fragmentation of lichen cover into fractions is proposed.
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| 2. |
- Gilichinsky, Michael, et al.
(författare)
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Histogram matching for the calibration of kNN stem volume estimates
- 2012
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Ingår i: International Journal of Remote Sensing. - : Informa UK Limited. - 0143-1161 .- 1366-5901. ; 33, s. 7117-7131
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we have tested HM for the calibration of kNN total stem volume raster maps to the reference distribution captured by a forest inventory (FI) from 106 stands in Stromsjoliden, in the north of Sweden. The available field FI data set comprises 1084 circular plots, divided into a reference data set and an evaluation data set of total stem volume observations. The reference data set was used for the creation of a cumulative frequency histogram of total stem volume and the evaluation data set was used to assess the accuracy of volume estimates, before and after HM. The HM adjusted the cumulative distribution of the kNN data set to the distribution of the reference observations and resulted in a distribution of kNN estimates of total stem volume, which corresponded closely to that of the evaluation data set. The results show that the variation range of the kNN stem volume estimates can be extended by HM both on the pixel and stand levels. The extension of the range of estimates towards the range provided by the field observations allows improvement of kNN volume estimation for use in forest management planning based on stand-level analysis, given that the reference stem volume distribution can be estimated accurately, for example, using field data from NFI.
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| 3. |
- Gilichinsky, Michael
(författare)
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Knowledge-based classification of land cover for the quality assessement of GIS database
- 2010
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Ingår i: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. - 1682-1750 .- 2194-9034. ; XXXVIII-4-8-2/W9, s. 217-222
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Valid classification of remotely sensed data is one of the most studied issues in the geoinformation science. In recent years knowledge-based approach to image analysis has been developing for assessment and improvement of traditional statistically-based image classification. Knowledge-based classification procedure integrates remote sensing imagery with ancillary geospatial information from GIS. Data about land cover stored in GIS database are usually subjected to an intensive change processes that diminish their relevance and include different types of discrepant information. Classification of land cover by up-to-date satellite imagery and automatic updating of GIS database allows revision of discrepant or erroneous data. The knowledge-based classification doesn’t require any assumptions regarding the data distribution and allows straightforward incorporation of ancillary data from GIS. Compared to traditional mapping approaches knowledge-based classification has the advantages of lower cost, area-wide coverage, and possibility to frequent updating. In perspective of large GIS maintenance the knowledge-based classification may contribute to detection of change and assist automatic updating of spatial databases. The objective of this study was to perform knowledge-based classification of land cover using satellite remote sensing data and GIS ancillary data. The selected target groups of land cover from the Israeli National GIS have been characterized spectrally by multispectral IKONOS data and geometrically by GIS data. The formalized knowledge about the target groups was incorporated into classification of remote sensing data. By means of classification results the discrepant land cover polygons have been detected and suggested for revision. Discussed are classification results and the analysis of detected discrepancies. The classification results have provided an indication of the utility of formalized knowledge for classification of land cover. The proposed method could be one possible approach to quality assessment and may contribute to automatic updating of existing spatial databases
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| 4. |
- Gilichinsky, Michael, et al.
(författare)
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Mapping ground lichens using forest inventory and optical satellite data
- 2011
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Ingår i: International Journal of Remote Sensing. - : Informa UK Limited. - 0143-1161 .- 1366-5901. ; 32:2, s. 455-472
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Tidskriftsartikel (refereegranskat)abstract
- Lichen is a major forage resource for reindeer and may constitute up to 80% of areindeer’s winter diet. The reindeer grazing area in Sweden covers almost half of thecountry, with reindeer using mountainous areas in the summer and forested areas inthe winter. Knowledge about the spatial distribution of ground lichens is importantfor both practical and decision-making purposes. Since the early 1980s, remotesensing research of lichen cover in northern environments has focused on reindeergrazing issues. The objective of this study was to use lichen information collected inthe Swedish National Forest Inventory (NFI) as training data to classify opticalsatellite images into ground lichen cover classes. The study site was located within thereindeer husbandry area in northern Sweden and consisted of the common areabetween two contiguous Satellite Pour l’Observation de la Terre (SPOT)-5 scenesand one Landsat-7 Enhanced Thematic Mapper Plus (ETMþ) scene. Three classificationmethods were tested: Mahalanobis distance, maximum likelihood andspectral mixture analysis. Post-classification calibration was applied using a membershipprobability threshold in order to match the NFI-measured proportions oflichen coverage classes. The classification results were assessed using an independentlycollected field dataset (229 validation areas). The results demonstrated highclassification accuracy of SPOT imagery for the classification of lichen-abundantand lichen-poor areas when using theMahalanobis distance classifier (overall accuracy84.3%, kappa ¼ 0.68). The highest classification accuracy for Landsat wasachieved using a maximum likelihood classification (overall accuracy 76.8%, kappa¼ 0.53). These results provided an initial indication of the utility of NFI data astraining data in the process of mapping lichen classes over large areas.
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| 5. |
- Gilichinsky, Michael
(författare)
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Measurements of Morphometric Parameters From Digital Elevation Models
- 2010
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Ingår i: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. - 1682-1750 .- 2194-9034. ; 38-4-8, s. 138-145
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Konferensbidrag (refereegranskat)abstract
- The present research examines the measured morphometric values of monogenetic cinder cones in the Tolbachik volcanic field (Kluchevskaya volcanic group, Kamchatka). The cones were measured from digital elevation models derived from satellite data (ASTER and SRTM) and from digitized topographic maps. The GPS measurements of 85 locations were performed in the field to provide geodetic reference for DEM processing as well as to assess the accuracy of the DEM. A methodology for morphometric measurements on a DEM is proposed. The morphometric parameters derived from a DEM include the main characteristics that control the rate of degradational evolution of the cone: height, width and slope. The measured morphometric values were compared and accuracy assessment was carried out.Our study analyzes the morphometric values of four recent cinder cones formed during the last basaltic eruption in 1975-76, and of five older ones formed during the last 2000 years. We show that morphometric values obtained from a DEM are affected by the resolution change, and characteristics of the same cinder cone may vary in their values among DEMs of different resolutions. According to the results, the morphometry of the cinder cones can be well characterized by a DEM derived from remotely sensed data. The calculated morphometric parameters showed a correlation with the spatial resolution of the DEM and relative age of the cinder cones. All studied DEM (including coarse resolution SRTM) were found suitable for morphometric measurements under the constraint of spatial resolution.
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| 6. |
- Gilichinsky, Michael
(författare)
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Morphometric and morphological development of Holocene cinder cones: A field and remote sensing study in the Tolbachik volcanic field, Kamchatka
- 2011
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Ingår i: Journal of Volcanology and Geothermal Research. - : Elsevier BV. - 0377-0273. ; 201, s. 301-311
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of landscape over time is a central aspect of geological, paleogeographical and geomorphological studies. Volcanic features like cinder cones offer the opportunity to monitor the processes and development of the landscape. Cinder cones are perhaps the simplest and most common volcanic landforms in the world. Morphological and morphometric study of cinder cones has proven an efficient tool for determining their relative dates, and the erosional processes affecting them. The extensive Kamchatka volcanic province (Russian Far East), with its large Tolbachik cinder cone field, is an excellent case study for spatial and temporal classification and calibration of changes in morphometric values with time.We show how the morphological and morphometric values of the monogenetic cinder cones, measured in the field and by digital elevation models, can be used to validate their age and erosional processes.Field data were GPS measurements of cinder cones formed at the Tolbachik 1975-1976 eruption and of Holocene cinder cones; erosion processes on the cinder cones and lava flows were identified and evaluated. For every studied cinder cone morphometric parameters were assessed on the basis of remotely sensed data and digital elevation model. Morphometric measurements were taken of cone height and slope and average axis diameter and the height-width ratio was obtained.The comparison of morphometric parameters calculated from ASTER DEM and topographic map clearly supports the concept of relative morphometric dating as the most recent cinder cones are always associated with the highest slopes and h/W ratio. The measured morphometric values of the recent Tolbachik cinder cones are valuable benchmark data for determining erosion rates, such as the measured values for the Paricutin cone in Mexico after the 1943 eruption. The variability of the morphometric values of the recent cinder cones is due to their lithological coarse composition. A comparison with the older cinder cones in the area shows that the climatic conditions of the Kamchatka peninsula and the slow development of vegetation cover determine a high rate of erosion and rapid change in the morphometric values, as compared to published values for other volcanic fields. (C) 2010 Elsevier B.V. All rights reserved.
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| 7. |
- Gilichinsky, Michael
(författare)
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Morphometric measurements of cinder cones from digital elevation models of Tolbachik volcanic field, central Kamchatka
- 2010
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Ingår i: Canadian Journal of Remote Sensing. - : Informa UK Limited. - 0703-8992 .- 1712-7971. ; 36, s. 287-300
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Tidskriftsartikel (refereegranskat)abstract
- The present research examines the measured morphometric values of monogenetic cinder cones in the Tolbachik volcanic field, Kluchevskaya volcanic group, Kamchatka. The cones were measured from digital elevation models (DEMs) derived from satellite data (ASTER, ALOS PALSAR, and SRTM) and from digitized topographic maps. GPS measurements of 85 locations were performed in the field to provide geodetic reference for DEM processing and to assess the accuracy of the DEM. A methodology for morphometric measurements on a DEM is proposed. The morphometric parameters derived from a DEM include the main characteristics that control the rate of degradational evolution of the cone, namely height, width, and slope. The measured morphometric values were compared and accuracy assessment was carried out. Our study analyzes the morphometric values of four recent cinder cones formed during the last basaltic eruption in 1975–1976 and five older cinder cones formed during the last 2000 years.We show that morphometric values obtained from a DEM are affected by the resolution change, and characteristics of the same cinder cone may vary among DEMs of different resolutions. Our results indicate that the morphometry of the cinder cones can be well characterized by a DEM derived from remotely sensed data. The calculated morphometric parameters showed a correlation with the spatial resolution of the DEM and relative age of the cinder cones. All DEMs studied (including coarse-resolution SRTM) were found to provide reliable morphometric parameters, although the calculated values varied as a function of spatial resolution
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| 8. |
- Gilichinsky, Michael
(författare)
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Morphometry of volcanic cones on Mars in perspective of Astrobiological Research
- 2015
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Ingår i: International Journal of Astrobiology. - 1473-5504. ; 14, s. 537-545
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Tidskriftsartikel (refereegranskat)abstract
- The permanently frozen volcanic sediment is one of the most promising geological objects for searching life on Mars. On Earth, volcanic intrusions into permafrost result in formation of the unique microbial communities. We propose several terrestrial analogues of Martian polar volcanoes, such as the permanently frozen volcanic sediments on the Kamchatka peninsula and in Antarctica. The present study shows applicability of the morphometric analysis for demonstration of the morphological similarity between the terrestrial and Martian cinder cones. In the present work, the morphometric analysis of young Martian landforms is based on the assumption that the conical structures identified on digital terrain model (DTM) are volcanic cinder cones. Morphometric analysis of the studied cones showed a range of degradation. The extent of degradation may be an indicator of age based on comparison with volcanic cinder cones on Earth. A morphometric analysis of potentially young volcanic cones in the North Polar Region of Mars was performed to estimate their relative age. The 14 potential cinder cones were identified using the DTM provided by Mars Express High Resolution Stereo Camera (HRSC), allowing for the basic morphometric calculations. The majority of the cinder cones are localized in the Chasma Boreale region within the area 79 degrees-81 degrees N and 261 degrees-295 degrees E. The calculated morphometric parameters showed that the cone average steepness varied from 3.4 degrees to 11.8 degrees, cone height-to-width ratio varied from 0.025 to 0.12, and the ratio between surface and basal area of the cone varied from 1.005 to 1.131. The studied cinder cones were classified with respect to the morphometric ratios assuming that larger values correspond to the younger structures. Employing the terrestrial analogy of morphometric ratios as a proxy for relative geological age, we suggest that existing microorganisms may be found in permafrost of young Martian cinder cones.
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| 9. |
- Gilichinsky, Michael, et al.
(författare)
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Reflectance changes due to pine sawfly attack detected using multitemporal SPOT satellite data
- 2013
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Ingår i: Remote Sensing Letters. - 2150-704X .- 2150-7058. ; 4, s. 10-18
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the relationship between Leaf Area Index (LAI) reduction in pine stands caused by pine sawfly (Neodiprion sertifier) larva and reflectance change measured using multitemporal optical satellite data. The study was carried out in 552 Scots Pine (Pinus sylvestris)-dominated stands in southern Norway (60 degrees 41' N, 12 degrees 18' E). Post-damage Satellite Pour l'Observation de la Terre (SPOT) satellite data were calibrated to surface reflectance using reflectance products of the moderate-resolution imaging spectroradiometer (MODIS). Standwise reflectance change was then computed by subtracting a pre-damage SPOT image that had been relative calibrated to the post-damage image using histogram matching. The reflectance changes were related to changes in LAI obtained from multitemporal lidar data calibrated with field measurements made with a LiCOR LAI-2000 plant canopy analyser. The reduced needle biomass growth due to the insect damage caused an increase in reflectance on the order of 0.002-0.015 in the visible and short-wave infrared SPOT bands and a decrease of 0.01 in the near infrared (NIR) band compared with a large reference data set with normally developed stands. A cross-validated discriminant analysis showed that 79% of the damaged stands could be separated from the undamaged stands by using the SPOT data.
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| 10. |
- Johnson, Sarah Stewart, et al.
(författare)
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Ancient bacteria show evidence of DNA repair
- 2007
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Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 104:36, s. 14401-14405
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Tidskriftsartikel (refereegranskat)abstract
- Recent claims of cultivable ancient bacteria within sealed environments highlight our limited understanding of the mechanisms behind long-term cell survival. It remains unclear how dormancy, a favored explanation for extended cellular persistence, can cope with spontaneous genomic decay over geological timescales. There has been no direct evidence in ancient microbes for the most likely mechanism, active DNA repair, or for the metabolic activity necessary to sustain it. In this paper, we couple PCR and enzymatic treatment of DNA with direct respiration measurements to investigate long-term survival of bacteria sealed in frozen conditions for up to one million years. Our results show evidence of bacterial survival in samples up to half a million years in age, making this the oldest independently authenticated DNA to date obtained from viable cells. Additionally, we find strong evidence that this long-term survival is closely tied to cellular metabolic activity and DNA repair that over time proves to be superior to dormancy as a mechanism in sustaining bacteria viability.
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