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1
Laprise, Danielle, und Serge Payette. „Évolution récente d'une tourbière à palses (Québec subarctique) : analyse cartographique et dendrochronologique“. Canadian Journal of Botany 66, Nr. 11 (01.11.1988): 2217–27. http://dx.doi.org/10.1139/b88-304.
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During the past 100 years, palsa bogs located on the eastern coast of Hudson Bay have undergone major changes associated with global climatic warming of the northern hemisphere. The recent main developmental stages of palsas, collapse scars, and thermokarstic pools were reconstructed within a representative permafrost peatland located in the southern part of the forest–tundra, using detailed mapping and tree-ring analyses. Maps of the peatland in 1957, 1973, and 1983 indicate a 49% decrease of the total cover of palsas and collapse scars between 1957 and 1983 and a 44% increase of the thermokarstic pool surface. Degradation of the palsa bog was more pronounced between 1957 and 1973 than between 1973 and 1983. Tree-ring analysis of reaction wood on black spruce (Picea mariana (Mill.) BSP.) exposed to unstable peat substratum indicates that permafrost degradation, which began as early as 1880, increased markedly between 1930 and 1965. During the 19th century, the permafrost peatland was mainly composed of large peat plateaus, which subsequently disintegrated into residual palsas, collapse scars, and thermokarstic pools. In addition the increase in temperature during the 20th century, it seems that milder winters with heavier snowfalls promoted conditions conducive to permafrost degradation. The constantly increasing contrast in the microtopographic pattern of the peatland, resulting from the transformation of peat plateaus into smaller palsa units, created more snow cover on east and southeast palsa slopes, thus accelerating permafrost degradation. This autocatalytic process seems to have also played a role in some sections of the peatland with abundant thermokarstic pools, where major changes in drainage conditions have stimulated thermokarstic erosion.
2
Seppälä, Matti. „Synthesis of studies of palsa formation underlining the importance of local environmental and physical characteristics“. Quaternary Research 75, Nr. 2 (März 2011): 366–70. http://dx.doi.org/10.1016/j.yqres.2010.09.007.
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AbstractThis review presents a synthesis of four decades of palsa studies based on field experiments and observations mainly in Fennoscandia, as well as laboratory measurements. Palsas are peat-covered mounds with a permanently frozen core; in Finnish Lapland, they range from 0.5 to 7 m in height and from 2 to 150 m in diameter. These small landforms are characteristic of the southern margin of the discontinuous permafrost zone. Palsa formation requires certain environmental conditions: long-lasting air temperature below 0°C, thin snow cover, and low summer precipitation. The development and persistence of their frozen core is sensitive to the physical properties of peat. The thermal conductivity of wet and frozen peat is high, and it decreases significantly as the peat dries and thaws. This affects the development of the active layer and makes its response to climate change complex. The insulating properties of dry peat during hot and dry summers moderate the thawing of the active layer on palsas. In contrast, humid and wet weather during the summer causes deep thawing and may destroy the frozen core of palsas. Ice layers in palsas have previously been interpreted as ice segregation features but because peat is not frost-susceptible, the ice layers are now reinterpreted as resulting from ice growth at the base of a frozen core that is effectively floating in a mire.
3
LUOTO, MISKA, RISTO K. HEIKKINEN und TIMOTHY R. CARTER. „Loss of palsa mires in Europe and biological consequences“. Environmental Conservation 31, Nr. 1 (März 2004): 30–37. http://dx.doi.org/10.1017/s0376892904001018.
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Palsa mires are northern mire complexes with permanently frozen peat hummocks. These are degrading throughout their distribution range, probably because of regional climatic warming. This review of the current understanding of the geographical, climatic and biological characteristics of palsa mires focuses on Europe. Recent studies have reported a drastic decrease in the extent of palsa mires in Fennoscandia; in Finland, the distribution of palsas was formerly about three times that at present. With continued or accelerated warming, as predicted for high latitudes, further extensive degradation or the wholesale disappearance of palsa mires seems inevitable. Palsa mires are known to be biologically heterogeneous environments with a rich diversity of bird species, and they are listed as a priority habitat type by the European Union. However, their role as habitats for other organisms is still poorly understood. There is urgent need for research and monitoring to assess the ecological and biological consequences of the decline of palsa mires in Europe.
4
Pissart, A. „Palsas, lithalsas and remnants of these periglacial mounds. A progress report“. Progress in Physical Geography: Earth and Environment 26, Nr. 4 (Dezember 2002): 605–21. http://dx.doi.org/10.1191/0309133302pp354ra.
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There is no general agreement about the meaning of the word ‘palsa’. Usage and recent suggested definitions indicate that the word is chiefly used for cryogenic mounds covered by peat that were formed by an accumulation of segregation ice in the discontinuous permafrost zone. Lithalsas are similar mounds, but without any peat cover. The thickness of aggradation ice on the top of lithalsas can be considerable. Use of development and decay palsas as indicators of climatic change is difficult. The climatic conditions in which lithalsas form are much more restricted than those for palsas and, as a consequence, regions where lithalsas exist are rather rare. After melting, lithalsas leave ramparted depressions; the mass movements on the peaty slopes of palsas are less propitious to the formation of ramparts. Some of the pingo remnants described in western Europe are, more accurately, lithalsa traces.
5
Allard, Michel, und Luc Rousseau. „The international structure of a pala and a peat plateau in the Rivière Boniface region, Québec: Interferences on the formation of ice segregation mounds“. Géographie physique et Quaternaire 53, Nr. 3 (02.10.2002): 373–87. http://dx.doi.org/10.7202/004760ar.
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Abstrat The internal structure of a 5.7 m high palsa was studied through a pattern of closely spaced drill holes in permafrost along two orthogonal section lines. Holes were also drilled on a 1.3 m high peat plateau along a topographic transect for comparison purposes. The morphology of the palsa closely reflects the shape of the ice-rich core heaved by the growth of thick ice lenses in thick marine clay silts of the Tyrrell Sea. During and since palsa growth, the sand and peat covering was deformed by gelifluction and sliding and was also partly eroded by overland flow and wind. Palsa growth was accompanied by the formation of numerous ice-filled fault planes in the frozen sediments. The peat plateau was heaved to a lower height through the formation of thin ice lenses in an underlying layer of sandy silt only 1.4 m thick; this sediment is believed to be of intertidal origin. Therefore, the local Quaternary geomorphological settings are at the origin of differences in morphology and size between the palsa and the peat plateau. General inferences for the development of palsas and like landforms are made from the findings of the study.
6
Fronzek, S., T. R. Carter und M. Luoto. „Evaluating sources of uncertainty in modelling the impact of probabilistic climate change on sub-arctic palsa mires“. Natural Hazards and Earth System Sciences 11, Nr. 11 (08.11.2011): 2981–95. http://dx.doi.org/10.5194/nhess-11-2981-2011.
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Abstract. We present an analysis of different sources of impact model uncertainty and combine this with probabilistic projections of climate change. Climatic envelope models describing the spatial distribution of palsa mires (mire complexes with permafrost peat hummocks) in northern Fennoscandia were calibrated for three baseline periods, eight state-of-the-art modelling techniques and 25 versions sampling the parameter uncertainty of each technique – a total of 600 models. The sensitivity of these models to changes in temperature and precipitation was analysed to construct impact response surfaces. These were used to assess the behaviour of models when extrapolated into changed climate conditions, so that new criteria, in addition to conventional model evaluation statistics, could be defined for determining model reliability. Impact response surfaces were also combined with climate change projections to estimate the risk of areas suitable for palsas disappearing during the 21st century. Structural differences in impact models appeared to be a major source of uncertainty, with 60% of the models giving implausible projections. Generalized additive modelling (GAM) was judged to be the most reliable technique for model extrapolation. Using GAM, it was estimated as very likely (>90% probability) that the area suitable for palsas is reduced to less than half the baseline area by the period 2030–2049 and as likely (>66% probability) that the entire area becomes unsuitable by 2080–2099 (A1B emission scenario). The risk of total loss of palsa area was reduced for a mitigation scenario under which global warming was constrained to below 2 °C relative to pre-industrial climate, although it too implied a considerable reduction in area suitable for palsas.
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Saemundsson, Thorsteinn, Olafur Arnalds, Christof Kneisel, Helgi Pall Jonsson und Armelle Decaulne. „The Orravatnsrustir palsa site in Central Iceland—Palsas in an aeolian sedimentation environment“. Geomorphology 167-168 (September 2012): 13–20. http://dx.doi.org/10.1016/j.geomorph.2012.03.014.
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Shishkonankova, E. A., N. A. Avetov, T. Yu Tolpysheva und A. A. Tarlinskaya. „Plant indication of thermocarst forms in palsa mires in the south of Nature Park Numto (West Siberia)“. SOCIALNO-ECOLOGICHESKIE TECHNOLOGII 9, Nr. 1 (2019): 27–57. http://dx.doi.org/10.31862/2500-2961-2019-9-1-27-57.
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Currently, palsa mires in the southern limit of circumpolar permafrost zone are characterized by an increased intensity of thermokarst processes. In the south of Nature Park Numto the cyclic character of frozen mound formation was replaced by their unidirectional degradation as a result of thaw. We analyze plant indicators of various thermokarst forms occurring in mounds: denudation spots, slumps and funnels. Depending on the stages of thermokarst and type of palsas (flat mound or large mound ones) a number of plant indicators of thawing is revealed: “the drunken forest”, the loss of dwarf shrubs and lichens and their secondary colonization, eutrophication of communities, the emergence of the “ridges” of vegetatively mobile species and others. Brown mosses and secondary colonizing Cladonia lichens with cup-shaped and club-like podetia are indicators of slow thermokarst on patches of denudation in large mounds. Meanwhile, the role of Cladonia lichens with richly branched podetia is markedly reduced. Mesotrophic communities, dominated by mesotrophic sphagnum mosses, are formed in deep funnels on large mounds under the conditions of frozen bed existence. The development of eutrophic communities indicates the release of nutrients during the melting of peat. The stages of thermokarst on the flat palsa mounds correspond to the following succession row: lichens + dwarf shrubs → hygrophyte sphagnum mosses and / or brown mosses + liverworts → hygro-hydrophyte sphagnum mosses + Warnstorfia fluitans. Reliable and the most long-term indicator of thermokarst on large mounds is the downy birch (Betula pubescens).
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Alewell, C., R. Giesler, J. Klaminder, J. Leifeld und M. Rollog. „Stable carbon isotopes as indicators for micro-geomorphic changes in palsa peats“. Biogeosciences Discussions 8, Nr. 1 (19.01.2011): 527–48. http://dx.doi.org/10.5194/bgd-8-527-2011.
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Abstract. Palsa peats are unique northern ecosystems formed under an arctic climate and characterized by an unique biodiversity and ecology. The stability of the palsas are seriously threatened by climate warming which will change the permafrost dynamic and results in degradation of the mires. We used stable carbon isotope depth profiles in two palsa mires of Northern Sweden to track environmental change during the formation of the mires. Carbon isotope (δ13C) depth profile of the yet undisturbed mire Storflaket indicated very low to no degradation of the peat in the water saturated depressions (hollows) but increased rates of anaerobic degradation at the Stordalen site. The latter might be induced by degradation of the permafrost cores in the uplifted areas (hummocks) and subsequent braking and submerging of the hummock peat into the hollows due to climate warming. Carbon isotope depth profiles of hummocks indicated a turn from aerobic mineralisation to anaerobic degradation at a peat depth between 4 to 25 cm. The age of these turning point was 14C dated between 150 and 670 years and could thus not be caused by anthropogenically induced climate change. We found the uplifting of the hummocks due to permafrost heave the most likely explanation for our findings. We thus concluded that differences in carbon isotope profiles of the hollows might point to the disturbance of the mires due to climate warming or due to differences in hydrology. The characteristic profiles of the hummocks are indicators for micro-geomorphic change during permafrost up heaving.
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Oksanen, Pirita O., Peter Kuhry und Rimma N. Alekseeva. „Holocene Development and Permafrost History of the Usinsk Mire, Northeast European Russia“. Géographie physique et Quaternaire 57, Nr. 2-3 (22.09.2005): 169–87. http://dx.doi.org/10.7202/011312ar.
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Abstract This study discusses Holocene vegetation succession, permafrost dynamics and peat accumulation in the Usinsk mire, located in the Pechora lowlands of Northeast European Russia. At present, the area is situated in the extreme northern taiga subzone near the southern limit of permafrost. Reconstructions are based on plant macrofossil analysis, physico-chemical analysis and AMS (accelerator mass spectrometry) radiocarbon dating of two peat profiles investigated in detail. Additional information is available from seven other sites. Organic accumulation started at ca. 11 350 BP (14C yrs). Terrestrialization of ponds was the most common pathway for mire initiation. During a large part of their history, the sites have been Cyperaceae-dominated fens. A change into Sphagnum-dominated ecosystems is recorded at 3700-3000 BP. Permafrost became established around 2300 BP, although first signs of embryonic palsa formation can be tentatively traced back to about 2900 BP. Palsas and peat plateaus have experienced several periods of freezing and entire or partial thawing. The extant permafrost stages are young. The long-term carbon accumulation rate in the investigated sites is 19 g/m2/yr. The average rate of carbon accumulation in the dynamic permafrost stage is 23 g/m2/yr.
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Touzi, Ridha, und Masanobu Shimada. „Polarimetric PALSAR Calibration“. IEEE Transactions on Geoscience and Remote Sensing 47, Nr. 12 (Dezember 2009): 3951–59. http://dx.doi.org/10.1109/tgrs.2009.2032176.
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12
Hong, M. –G, und C. Kim. „STANDWISE CHANGE DETECTION FOR GROWING STOCK USING REPEAT-PASS ALOS PALSAR / PALSAR-2 DATA“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (22.06.2016): 841–45. http://dx.doi.org/10.5194/isprs-archives-xli-b7-841-2016.
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This study demonstrates the possibility of detecting the changes of growing stocks in mountainous forest stands derived from ALOS PALSAR and PALSAR-2 images. The ALOS PALSAR were obtained over the Kwangneung Experiment Forest (KEF, Korea) during the period of nineteen and a half months from the April 26, 2009 to December 12, 2010, whereas the PALSAR-2 data were acquired on the April 7, 2015. The KEF test site comprises 58 stands, which cover approximately 1,000ha and have steep slope topography. Owing to topographic effects of SAR data in mountainous areas, the DEM-assisted topographic normalized backscattering coefficient γ<sup>0</sup> was applied to the evaluation of the relationships between the ALOS PALSAR / PALSAR-2 HV backscatter and the field inventory–based stand stock volume. The results indicate that: 1) the γ<sup>0</sup> values for the volume obtained from ALOS PALSAR data on December 12, 2010 show a gradual increase higher than those computed from the data on April 26, 2009, here the γ<sup>0</sup> value increases in accordance with an increase in the volume: 2) the γ<sup>0</sup> values determined from the PALSAR-2 data increase with the same inventory-based volume, when compared with those computed from both ALOS PALSAR data. They also increase substantially as the values of the volume rise, with the exception of the volume interval from 130 m<sup>3</sup> ha<sup>−1</sup> to 160 m<sup>3</sup> ha<sup>−1</sup>. This is understandable because the volume of the aforementioned interval has been reduced through clearing. Consequently, the γ<sup>0</sup>–based relationship between PALSAR-2 HV backscatter and growing stock can lead to detecting the stand growth changes in the KEF of Korea.
13
Arai, Hironori, Wataru Takeuchi, Kei Oyoshi, Lam Nguyen und Kazuyuki Inubushi. „Estimation of Methane Emissions from Rice Paddies in the Mekong Delta Based on Land Surface Dynamics Characterization with Remote Sensing“. Remote Sensing 10, Nr. 9 (09.09.2018): 1438. http://dx.doi.org/10.3390/rs10091438.
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In paddy soils in the Mekong Delta, soil archaea emit substantial amounts of methane. Reproducing ground flux data using only satellite-observable explanatory variables is a highly transparent method for evaluating regional emissions. We hypothesized that PALSAR-2 (Phased Array type L-band Synthetic Aperture RADAR) can distinguish inundated soil from noninundated soil even if the soil is covered by rice plants. Then, we verified the reproducibility of the ground flux data with satellite-observable variables (soil inundation and cropping calendar) and with hierarchical Bayesian models. Furthermore, inundated/noninundated soils were classified with PALSAR-2. The model parameters were successfully converged using the Hamiltonian–Monte Carlo method. The cross-validation of PALSAR-2 land surface water coverage (LSWC) with several inundation indices of MODIS (Moderate Resolution Imaging Spectroradiometer) and AMSR-2 (Advanced Microwave Scanning Radiometer-2) data showed that (1) high PALSAR-2-LSWC values were detected even when MODIS and AMSR-2 inundation index values (MODIS-NDWI and AMSR-2-NDFI) were low and (2) low values of PALSAR-2-LSWC tended to be less frequently detected as the MODIS-NDWI and AMSR-2-NDFI increased. These findings indicate the potential of PALSAR-2 to detect inundated soils covered by rice plants even when MODIS and AMSR-2 cannot, and show the similarity between PALSAR-2-LSWC and the other two indices for nonvegetated areas.
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Hong, M. –G, und C. Kim. „STANDWISE CHANGE DETECTION FOR GROWING STOCK USING REPEAT-PASS ALOS PALSAR / PALSAR-2 DATA“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (22.06.2016): 841–45. http://dx.doi.org/10.5194/isprsarchives-xli-b7-841-2016.
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This study demonstrates the possibility of detecting the changes of growing stocks in mountainous forest stands derived from ALOS PALSAR and PALSAR-2 images. The ALOS PALSAR were obtained over the Kwangneung Experiment Forest (KEF, Korea) during the period of nineteen and a half months from the April 26, 2009 to December 12, 2010, whereas the PALSAR-2 data were acquired on the April 7, 2015. The KEF test site comprises 58 stands, which cover approximately 1,000ha and have steep slope topography. Owing to topographic effects of SAR data in mountainous areas, the DEM-assisted topographic normalized backscattering coefficient γ<sup>0</sup> was applied to the evaluation of the relationships between the ALOS PALSAR / PALSAR-2 HV backscatter and the field inventory–based stand stock volume. The results indicate that: 1) the γ<sup>0</sup> values for the volume obtained from ALOS PALSAR data on December 12, 2010 show a gradual increase higher than those computed from the data on April 26, 2009, here the γ<sup>0</sup> value increases in accordance with an increase in the volume: 2) the γ<sup>0</sup> values determined from the PALSAR-2 data increase with the same inventory-based volume, when compared with those computed from both ALOS PALSAR data. They also increase substantially as the values of the volume rise, with the exception of the volume interval from 130 m<sup>3</sup> ha<sup>−1</sup> to 160 m<sup>3</sup> ha<sup>−1</sup>. This is understandable because the volume of the aforementioned interval has been reduced through clearing. Consequently, the γ<sup>0</sup>–based relationship between PALSAR-2 HV backscatter and growing stock can lead to detecting the stand growth changes in the KEF of Korea.
15
Rampersad, Narad, Jeffrey Shallit und Ming-wei Wang. „Inverse star, borders, and palstars“. Information Processing Letters 111, Nr. 9 (April 2011): 420–22. http://dx.doi.org/10.1016/j.ipl.2011.01.018.
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Borge, Amund F., Sebastian Westermann, Ingvild Solheim und Bernd Etzelmüller. „Strong degradation of palsas and peat plateaus in northern Norway during the last 60 years“. Cryosphere 11, Nr. 1 (02.01.2017): 1–16. http://dx.doi.org/10.5194/tc-11-1-2017.
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Abstract. Palsas and peat plateaus are permafrost landforms occurring in subarctic mires which constitute sensitive ecosystems with strong significance for vegetation, wildlife, hydrology and carbon cycle. Firstly, we have systematically mapped the occurrence of palsas and peat plateaus in the northernmost county of Norway (Finnmark, ∼ 50 000 km2) by manual interpretation of aerial images from 2005 to 2014 at a spatial resolution of 250 m. At this resolution, mires and wetlands with palsas or peat plateaus occur in about 850 km2 of Finnmark, with the actual palsas and peat plateaus underlain by permafrost covering a surface area of approximately 110 km2. Secondly, we have quantified the lateral changes of the extent of palsas and peat plateaus for four study areas located along a NW–SE transect through Finnmark by utilizing repeat aerial imagery from the 1950s to the 2010s. The results of the lateral changes reveal a total decrease of 33–71 % in the areal extent of palsas and peat plateaus during the study period, with the largest lateral change rates observed in the last decade. However, the results indicate that degradation of palsas and peat plateaus in northern Norway has been a consistent process during the second half of the 20th century and possibly even earlier. Significant rates of areal change are observed in all investigated time periods since the 1950s, and thermokarst landforms observed on aerial images from the 1950s suggest that lateral degradation was already an ongoing process at this time. The results of this study show that lateral erosion of palsas and peat plateaus is an important pathway for permafrost degradation in the sporadic permafrost zone in northern Scandinavia. While the environmental factors governing the rate of erosion are not yet fully understood, we note a moderate increase in air temperature, precipitation and snow depth during the last few decades in the region.
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Alewell, C., R. Giesler, J. Klaminder, J. Leifeld und M. Rollog. „Stable carbon isotopes as indicators for environmental change in palsa peats“. Biogeosciences 8, Nr. 7 (08.07.2011): 1769–78. http://dx.doi.org/10.5194/bg-8-1769-2011.
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Abstract. Palsa peats are unique northern ecosystems formed under an arctic climate and characterized by a high biodiversity and sensitive ecology. The stability of the palsas are seriously threatened by climate warming which will change the permafrost dynamic and induce a degradation of the mires. We used stable carbon isotope depth profiles in two palsa mires of Northern Sweden to track environmental change during the formation of the mires. Soils dominated by aerobic degradation can be expected to have a clear increase of carbon isotopes (δ13C) with depth, due to preferential release of 12C during aerobic mineralization. In soils with suppressed degradation due to anoxic conditions, stable carbon isotope depth profiles are either more or less uniform indicating no or very low degradation or depth profiles turn to lighter values due to an enrichment of recalcitrant organic substances during anaerobic mineralisation which are depleted in 13C. The isotope depth profile of the peat in the water saturated depressions (hollows) at the yet undisturbed mire Storflaket indicated very low to no degradation but increased rates of anaerobic degradation at the Stordalen site. The latter might be induced by degradation of the permafrost cores in the uplifted areas (hummocks) and subsequent breaking and submerging of the hummock peat into the hollows due to climate warming. Carbon isotope depth profiles of hummocks indicated a turn from aerobic mineralisation to anaerobic degradation at a peat depth between 4 and 25 cm. The age of these turning points was 14C dated between 150 and 670 yr and could thus not be caused by anthropogenically induced climate change. We found the uplifting of the hummocks due to permafrost heave the most likely explanation for our findings. We thus concluded that differences in carbon isotope profiles of the hollows might point to the disturbance of the mires due to climate warming or due to differences in hydrology. The characteristic profiles of the hummocks are indicators for micro-geomorphic change during permafrost up heaving.
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Beiranvand Pour, A., und M. Hashim. „INTEGRATION OF PALSAR AND ASTER SATELLITE DATA FOR GEOLOGICAL MAPPING IN TROPICS“. ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences II-2/W2 (19.10.2015): 105–9. http://dx.doi.org/10.5194/isprsannals-ii-2-w2-105-2015.
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This research investigates the integration of the Phased Array type L-band Synthetic Aperture Radar (PALSAR) and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite data for geological mapping applications in tropical environments. The eastern part of the central belt of peninsular Malaysia has been investigated to identify structural features and mineral mapping using PALSAR and ASTER data. Adaptive local sigma and directional filters were applied to PALSAR data for detecting geological structure elements in the study area. The vegetation, mineralogic and lithologic indices for ASTER bands were tested in tropical climate. Lineaments (fault and fractures) and curvilinear (anticline or syncline) were detected using PALSAR fused image of directional filters (N-S, NE-SW, and NW-SE).Vegetation index image map show vegetation cover by fusing ASTER VNIR bands. High concentration of clay minerals zone was detected using fused image map derived from ASTER SWIR bands. Fusion of ASTER TIR bands produced image map of the lithological units. Results indicate that data integration and data fusion from PALSAR and ASTER sources enhanced information extraction for geological mapping in tropical environments.
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Seppala, Matti. „The Origin of Palsas“. Geografiska Annaler. Series A, Physical Geography 68, Nr. 3 (1986): 141. http://dx.doi.org/10.2307/521453.
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Seppälä, Matti. „The Origin of Palsas“. Geografiska Annaler: Series A, Physical Geography 68, Nr. 3 (Oktober 1986): 141–47. http://dx.doi.org/10.1080/04353676.1986.11880167.
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Kojima, Yuki, Kazuo Oki, Kosuke Noborio und Masaru Mizoguchi. „Estimating Soil Moisture Distributions across Small Farm Fields with ALOS/PALSAR“. International Scholarly Research Notices 2016 (26.07.2016): 1–8. http://dx.doi.org/10.1155/2016/4203783.
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The ALOS (advanced land observing satellite) has an active microwave sensor, PALSAR (phased array L-band synthetic aperture radar), which has a fine resolution of 6.5 m. Because of the fine resolution, PALSAR provides the possibility of estimating soil moisture distributions in small farmlands. Making such small-scale estimates has not been available with traditional satellite remote sensing techniques. In this study, the relationship between microwave backscattering coefficient (σ) measured with PALSAR and ground-based soil moisture was determined to investigate the performance of PALSAR for estimating soil moisture distribution in a small-scale farmland. On the ground at a cabbage field in Japan in 2008, the soil moisture distribution of multiple soil layers was measured using time domain reflectometry when the ALOS flew over the field. Soil moisture in the 0–20 cm soil layer showed the largest correlation coefficient with σ (r=0.403). The σ values also showed a strong correlation with the ground surface coverage ratio by cabbage plants. Our results suggested that PALSAR could estimate soil moisture distribution of the 0–20 cm soil layer across a bare field and a crop coverage ratio when crops were planted.
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Mizuochi, Hiroki, Chikako Nishiyama, Iwan Ridwansyah und Kenlo Nishida Nasahara. „Monitoring of an Indonesian Tropical Wetland by Machine Learning-Based Data Fusion of Passive and Active Microwave Sensors“. Remote Sensing 10, Nr. 8 (06.08.2018): 1235. http://dx.doi.org/10.3390/rs10081235.
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In this study, a novel data fusion approach was used to monitor the water-body extent in a tropical wetland (Lake Sentarum, Indonesia). Monitoring is required in the region to support the conservation of water resources and biodiversity. The developed approach, random forest database unmixing (RFDBUX), makes use of pixel-based random forest regression to overcome the limitations of the existing lookup-table-based approach (DBUX). The RFDBUX approach with passive microwave data (AMSR2) and active microwave data (PALSAR-2) was used from 2012 to 2017 in order to obtain PALSAR-2-like images with a 100 m spatial resolution and three-day temporal resolution. In addition, a thresholding approach for the obtained PALSAR-2-like backscatter coefficient images provided water body extent maps. The validation revealed that the spatial patterns of the images predicted by RFDBUX are consistent with the original PALSAR-2 backscatter coefficient images (r = 0.94, RMSE = 1.04 in average), and that the temporal pattern of the predicted water body extent can track the wetland dynamics. The PALSAR-2-like images should be a useful basis for further investigation of the hydrological/climatological features of the site, and the proposed approach appears to have the potential for application in other tropical regions worldwide.
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Rosenqvist, Jessica, Ake Rosenqvist, Katherine Jensen und Kyle McDonald. „Mapping of Maximum and Minimum Inundation Extents in the Amazon Basin 2014–2017 with ALOS-2 PALSAR-2 ScanSAR Time-Series Data“. Remote Sensing 12, Nr. 8 (22.04.2020): 1326. http://dx.doi.org/10.3390/rs12081326.
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Seasonal inundation is an important effect that governs the distribution of ecosystems in the tropics. In the Amazon Basin, the seasonal flood pulse causes a difference in high and low water levels that can exceed 15 m. The associated flood duration and extent play an important role in land-atmosphere carbon exchange and affect the ecosystem’s carbon pool that originates from organic matter transported from upland and flooded forests. Studies of wetlands inundation across the Amazon Basin have utilized dual season mosaics from JERS-1 and wide-swath ScanSAR data from ALOS PALSAR to characterize inundation across the basin. This study builds upon past efforts with JERS-1 and ALOS PALSAR and uses ALOS-2 PALSAR-2 ScanSAR data to generate annual maximum and minimum inundation extent maps over the full Amazon Basin for the period spanning November 2014–October 2017. The study uses decision tree classification to create a maximum and a minimum inundation extent map for each year over this time period. The results show that a generalized algorithm that fits the entire basin has an 86% overall accuracy compared with a classification made for a local region from the same PALSAR-2 datasets. Comparisons with previous full-basin inundation maps by other L-band radars shows similar results for inundated areas during maximum inundation. The maps derived previously from JERS-1 and ALOS PALSAR show 7.3% and 6.9% inundated vegetation, respectively, and this study using PALSAR-2 shows values ranging between 5.5% and 7.0% across the three study years. Comparisons between the stage data across the basin and acquisition dates/periods for JERS-1 and PALSAR-2 show that the sensors capture the nature of the maximum and minimum flooding across the basins but have not successfully captured the exact maximum and minimum flood levels that have been recorded in the stage data. The inundation maps are publicly available under a Creative Commons (CC BY 4.0) licensefrom the Alaska Satellite Facility.
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Khasanov, Khojiakbar, und Azamat Ahmedov. „Comparison of Digital Elevation Models for the designing water reservoirs: a case study Pskom water reservoir“. E3S Web of Conferences 264 (2021): 03058. http://dx.doi.org/10.1051/e3sconf/202126403058.
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This study investigates the accuracy of various DEMs (SRTM DEM, ASTER GDEM, and ALOS PALSAR DEM) for the area of the designing Pskom water reservoir (recommended to construction in Pskom River, in Tashkent region. DEMs are compared for the study area using the Global Mapper application and selection Ground Control Points (GCP). The RMSE we calculate is the most easily interpreted statistic as the square root of the mean square error because it has the same units as the quantity drawn on the vertical axis. Results show that SRTM based measurements of ground control points (GCPs) exhibit RMSE of 15.72 m while ASTER DEM based measurements exhibits and RMSE of 18.47 m, ALOS PALSAR exhibit RMSE of 14.02 m for the Water reservoir located in the plain. There are AOS PALSAR outperforms SRTM and ASTER DEM in detecting vertical accuracy. Based on the capabilities of the Global Mapper program, we can build the longitudinal profile of the approximate location where the dam can be built in each DEM and compare. The results obtained show that the dam height is 187 m at ALOS PALSAR DEM, 168 m at ASTER GDEM, and 175 m at SRTM. The study found that using ALOS PALSAR data in the design of the proposed Pskom Reservoir for construction leads to a more accurate result. Comparing the DEMs data shows that there is more difference between the vertical accuracy; the horizontal accuracy level is almost the same. The results were obtained using ALOS PALSAR data in determining the storage volume (W=479368568 m3) and area (F=8.31 sq., km) of the water reservoir.
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Gurney, S. D. „Aspects of the genesis, geomorphology and terminology of palsas: perennial cryogenic mounds“. Progress in Physical Geography: Earth and Environment 25, Nr. 2 (Juni 2001): 249–60. http://dx.doi.org/10.1177/030913330102500205.
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Palsas are true perennial permafrost mounds. It is generally accepted that there are at least three mechanisms which might contribute to the initiation of their formation, although these are not necessarily mutually exclusive. These mechanisms can be termed: the ‘snow cover’ hypothesis; the ‘vegetation succession’ hypothesis; and the ‘buoyancy’ hypothesis. Furthermore, there are at least three types of palsas recognized, although the terminology relating to these different varieties is varied and disputed. It is clear that palsas are potentially extremely useful features for monitoring permafrost growth and decay in certain areas, and that a unified understanding of their growth and decay processes would aid this.
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Pavanelli, João Arthur Pompeu, João Roberto dos Santos, Lênio Soares Galvão, Maristela Xaud und Haron Abrahim Magalhães Xaud. „PALSAR-2/ALOS-2 AND OLI/LANDSAT-8 DATA INTEGRATION FOR LAND USE AND LAND COVER MAPPING IN NORTHERN BRAZILIAN AMAZON“. Boletim de Ciências Geodésicas 24, Nr. 2 (Juni 2018): 250–69. http://dx.doi.org/10.1590/s1982-21702018000200017.
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Abstract: In northern Brazilian Amazon, the crops, savannahs and rainforests form a complex landscape where land use and land cover (LULC) mapping is difficult. Here, data from the Operational Land Imager (OLI)/Landsat-8 and Phased Array type L-band Synthetic Aperture Radar (PALSAR-2)/ALOS-2 were combined for mapping 17 LULC classes using Random Forest (RF) during the dry season. The potential thematic accuracy of each dataset was assessed and compared with results of the hybrid classification from both datasets. The results showed that the combination of PALSAR-2 HH/HV amplitudes with the reflectance of the six OLI bands produced an overall accuracy of 83% and a Kappa of 0.81, which represented an improvement of 6% in relation to the RF classification derived solely from OLI data. The RF models using OLI multispectral metrics performed better than RF models using PALSAR-2 L-band dual polarization attributes. However, the major contribution of PALSAR-2 in the savannahs was to discriminate low biomass classes such as savannah grassland and wooded savannah.
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Beiranvand Pour, A., und M. Hashim. „GEOLGICAL STRUCTURE MAPPING OF THE BENTONG-RAUB SUTURE ZONE, PENINSULAR MALAYSIA USING PALSAR REMOTE SENSING DATA“. ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences II-2/W2 (19.10.2015): 89–92. http://dx.doi.org/10.5194/isprsannals-ii-2-w2-89-2015.
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The Bentong-Raub Suture Zone (BRSZ) of peninsular Malaysia was selected as case study to evaluate the capability of the Phased Array type L-band Synthetic Aperture Radar (PALSAR) satellite remote sensing data for structural geology mapping in tropical environments. The structural elements in the BRSZ were enhanced using multi-polarization configuration of PALSAR data at a regional scale. Adaptive local sigma and directional filters were applied to PALSAR data for detailed structural mapping. Numerous tectonic lineaments with consistent variation in trend, length and density were detected in the study area. Structural analysis of the BRSZ reveals that two distinct parts can be defined, a western part affected mainly by ductile fabrics in the Cameron Highlands and an eastern part affected mainly by brittle deformation in the BRSZ. Ductile deformation indicates several generation of folding in the Cameron Highlands. Several faults, joints and fractures represent brittle deformation events in the BRSZ. The results of this study demonstrate the usefulness of PALSAR satellite remote sensing data for mapping geological structures in tropical environments.
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Shimada, M., O. Isoguchi, T. Tadono und K. Isono. „PALSAR Radiometric and Geometric Calibration“. IEEE Transactions on Geoscience and Remote Sensing 47, Nr. 12 (Dezember 2009): 3915–32. http://dx.doi.org/10.1109/tgrs.2009.2023909.
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Quina, Robson Rodrigues, Rômulo Montan Costa, Fabio de Oliveira Sanches, Francisco Carlos Moreira Gomes und Ricardo Tavares Zaidan. „Comparação de produtos altimétricos dos sensores Palsar/Alos e Lidar, a partir do modelo Sinmap“. Research, Society and Development 9, Nr. 12 (23.12.2020): e27391211149. http://dx.doi.org/10.33448/rsd-v9i12.11149.
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O estudo tem como principal objetivo analisar e mensurar a distribuição de Índices de Estabilidade a Escorregamentos, a partir da aplicação do modelo SINMAP, mediante o uso de dois produtos altimétricos: um proveniente do sensor PALSAR/ALOS e outro originado do sensor LIDAR, em uma mesma área de estudo. Buscou-se avaliar se o produto do sensor PALSAR, apresenta uma resposta satisfatória e aceitável para a aplicação em modelos de predição de escorregamentos, em localidades que não possuam base de dados, carentes de informações. Foi constatado que apesar do produto PALSAR, não apresentar a mesma acurácia e detalhamento do LIDAR, ambos possuem diversas similaridades. Contudo, a avaliação da homogeneidade de dados por meio da aplicação do Coeficiente e Determinação (R²) e do Coeficiente de Correlação de Pearson (r), bem como dos erros por meio do Erro Médio Absoluto (EMA), Erro Médio Relativo (EMR) e a Raiz do Erro Quadrático Médio (REQM), demonstraram que ambos os produtos apresentam forte similaridade. Contudo, considerou-se que o MDE existente no PALSAR/ALOS, apresenta resultados aceitáveis e convincentes de serem aplicados na identificação de áreas susceptíveis a escorregamentos, em locais que não dispõe de uma base de dados.
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Darmawan, S., W. Takeuchi, Y. Vetrita, K. Wikantika und D. K. Sari. „Impact of Topography and Tidal Height on ALOS PALSAR Polarimetric Measurements to Estimate Aboveground Biomass of Mangrove Forest in Indonesia“. Journal of Sensors 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/641798.
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This study is focused on investigating the impact of topography and tidal height on ALOS PALSAR polarimetric measurements on HH and HV for estimating aboveground biomass (AGB) of mangrove forest in Indonesia. We used multitemporal ALOS PALSAR polarimetric measurement that covered mangrove zone in Banyuasin, Cilacap, and Teluk Bintuni and also collected tidal height data within the same acquisition date with multitemporal ALOS PALSAR polarimetric measurement. We analyzed the distribution of flooding and nonflooding areas based on tidal height and SRTM topography data, created three profiles as region of interest (ROI), and got characteristics of backscatter value on HH and HV with different tidal height. The result of this study showed backscatter of the open mangrove zones during high tide with HH value less than −20 dB and HV value less than −25 dB whereas during low tide it showed an HH value around −20 to −10 dB and HV value around −25 to −10 dB. Backscatter of the middle mangrove zones at Cilacap, with low and flat topography, showed a deviation of backscatter on HV value of 1.6 dB. Finally, the average AGB of mangrove forest in Indonesia was estimated based on ALOS PALSAR polarimetric measurements.
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Qin, Yuanwei, Xiangming Xiao, Jean-Pierre Wigneron, Philippe Ciais, Josep G. Canadell, Martin Brandt, Xiaojun Li et al. „Annual Maps of Forests in Australia from Analyses of Microwave and Optical Images with FAO Forest Definition“. Journal of Remote Sensing 2021 (23.08.2021): 1–11. http://dx.doi.org/10.34133/2021/9784657.
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The Australian governmental agencies reported a total of 149 million ha forest in the Food and Agriculture Organization of the United Nations (FAO) in 2010, ranking sixth in the world, which is based on a forest definition with tree height>2 meters. Here, we report a new forest cover data product that used the FAO forest definition (tree cover>10% and tree height>5 meters at observation time or mature) and was derived from microwave (Phased Array type L-band Synthetic Aperture Radar, PALSAR) and optical (Moderate Resolution Imaging Spectroradiometer, MODIS) images and validated with very high spatial resolution images, Light Detection and Ranging (LiDAR) data from the Ice, Cloud, and land Elevation Satellite (ICESat), and in situ field survey sites. The new PALSAR/MODIS forest map estimates 32 million ha of forest in 2010 over Australia. PALSAR/MODIS forest map has an overall accuracy of ~95% based on the reference data derived from visual interpretation of very high spatial resolution images for forest and nonforest cover types. Compared with the canopy height and canopy coverage data derived from ICESat LiDAR strips, PALSAR/MODIS forest map has 73% of forest pixels meeting the FAO forest definition, much higher than the other four widely used forest maps (ranging from 36% to 52%). PALSAR/MODIS forest map also has a reasonable spatial consistency with the forest map from the National Vegetation Information System. This new annual map of forests in Australia could support cross-country comparison when using data from the FAO Forest Resource Assessment Reports.
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Feng, Jian-Peng, Xiao-Long Wang und Xiao-Ping Cao. „The First Total Synthesis of the (±)-Palstatin“. Chinese Journal of Chemistry 24, Nr. 2 (Februar 2006): 215–18. http://dx.doi.org/10.1002/cjoc.200690041.
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Shen, Wenjuan, Mingshi Li, Chengquan Huang, Xin Tao, Shu Li und Anshi Wei. „Mapping Annual Forest Change Due to Afforestation in Guangdong Province of China Using Active and Passive Remote Sensing Data“. Remote Sensing 11, Nr. 5 (27.02.2019): 490. http://dx.doi.org/10.3390/rs11050490.
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Accurate acquisition of spatial distribution of afforestation in a large area is of great significance to contributing to the sustainable utilization of forest resources and the evaluation of the carbon accounting. Annual forest maps (1986–2016) of Guangdong, China were generated using time series Landsat images and PALSAR data. Initially, four PALSAR-based classifiers were used to classify land cover types. Then, the optimal mapping algorithm was determined. Next, an accurate identification of forest and non-forest was carried out by combining Landsat-based phenological variables and PALSAR-based land cover classifications. Finally, the spatio-temporal distribution of forest cover change due to afforestation was created and its forest biomass dynamics changes were detected. The results indicated that the overall accuracy of forest classification of the improved model based on the PALSAR-based stochastic gradient boosting (SGB) classification and the maximum value of normalized difference vegetation index (NDVI; SGB-NDVI) were approximately 75–85% in 2005, 2010, and 2016. Compared with the Japan Aerospace Exploration Agency (JAXA) PALSAR-forest/non-forest, the SGB-NDVI-based forest product showed great improvement, while the SGB-NDVI product was the same or slightly inferior to the Global Land Cover (GLC) and vegetation tracker change (VCT)-based land cover types, respectively. Although this combination of multiple sources contained some errors, the SGB-NDVI model effectively identified the distribution of forest cover changes by afforestation events. By integrating aboveground biomass dynamics (AGB) change with forest cover, the trend in afforestation area closely corresponded with the trend in forest AGB. This technique can provide an essential data baseline for carbon assessment in the planted forests of southern China.
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Tadono, T., M. Ohki und T. Abe. „SUMMARY OF NATURAL DISASTER RESPONSES BY THE ADVANCED LAND OBSERVING SATELLITE-2 (ALOS-2)“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W7 (01.03.2019): 69–72. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w7-69-2019.
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<p><strong>Abstract.</strong> The Advanced Land Observing Satellite-2 (ALOS-2) was launched on May 24, 2014, and it is operating very well in space more than 4.5 years. The designed mission life is five years as nominal operational phase and the target is over seven years since launch the satellite. The mission objectives of ALOS-2 are 1) disaster monitoring, 2) national land and infrastructure information, 3) cultivated area monitoring, and 4) global forest monitoring. To achieve the objectives, ALOS-2 carries on the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2), which is an active microwave radar using the 1.2 GHz frequency band and observes in day and night times even in bad weather conditions as successor PALSAR instrument onboard ALOS satellite operated from 2006 to 2011. PALSAR-2 instrument has several enhanced features from PALSAR e.g. finer spatial resolution, spotlight observing mode, dual-polarisation ScanSAR. This paper summarises an introduction of typical data analysis results for monitoring natural disasters by ALOS-2 during the operational phase. As the response natural disasters, more than 400 times of the emergency observations have been conducted to identify damages caused by volcanic activities, earthquakes, flooding etc. happened in Japan and the World.</p>
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Nonaka, T., T. Asaka, K. Iwashita und F. Ogushi. „ANALYSIS OF THE TREND OF THE DEFORMATION AROUND KANTO REGION ESTIMATED BY TIME SERIES OF PALSAR-2 DATA“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W8 (22.08.2019): 287–91. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w8-287-2019.
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<p><strong>Abstract.</strong> The South Kanto gas field contains natural gas dissolved in water. In the past, large-scale land subsidence has occurred due to the extraction of this natural gas. Therefore, continuous and accurate monitoring for subsidence using satellite remote sensing is essential to prevent any extreme subsidence events, particularly in urban areas, and ensure the safety of residences. In this study, we adopted the small baseline subset (SBAS) method to understand the subsidence trend. We used Advanced Land Observing Satellite (ALOS)-2 Phased Array type L-band Synthetic Aperture Radar (PALSAR-2) data from 2015 to 2019 for this purpose. The results show that the maximum displacement around the Kujyukuri area is more than 10 mm/year and the mean displacement rate for 2015 to 2019 is -1.4 ± 3.2 mm/year; this value is not as large as some obtained with past PALSAR observations. Comparison of our results with PALSAR observations shows that the number of distributed targets is fewer and the root mean square error of each time-series displacement value is larger. Further quantitative analysis is required to discuss the reliability of the SBAS-derived displacement rates by PALSAR-2.</p>
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Molidena, Elis, Takahiro Osawa, Putu Gede Ardhana und Abd Rahman As-syakur. „Forest and Industrial Plantation Mapping with Multi-Temporal Dual Polarization by ALOS PALSAR Data In Riau Province“. International Journal of Environment and Geosciences 2, Nr. 1 (01.06.2018): 35. http://dx.doi.org/10.24843/ijeg.2018.v02.i01.p04.
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Backscattering characteristics of land use has been analyzed using ALOS PALSAR data. The purpose of this research are mapping of land use by five categories such as forest, acacia, oil palm, open area and water, and to identify the changes of environmental. Analysis Pixel-by-pixel average of ALOS PALSAR level 1.5 backscattering used from five of category land use was to estimate the spectral characteristic of each object in difference HH and HV polarization. Ground truth data was taken from 169 locations which used for classification, 119 locations and 50 locations used for validation. Two different times of ALOS PALSAR level 1.0 2009 and 2010 data, was used for changes detection by multi temporal color composite combination. The accuracy result for classification map shows 62% of ground truth database, and multi temporal analysis showed the possibility of changes.
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Zhang, Yihang, Feng Ling, Giles M. Foody, Yong Ge, Doreen S. Boyd, Xiaodong Li, Yun Du und Peter M. Atkinson. „Mapping annual forest cover by fusing PALSAR/PALSAR-2 and MODIS NDVI during 2007–2016“. Remote Sensing of Environment 224 (April 2019): 74–91. http://dx.doi.org/10.1016/j.rse.2019.01.038.
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Pereira, Luciana, Luiz Furtado, Evlyn Novo, Sidnei Sant’Anna, Veraldo Liesenberg und Thiago Silva. „Multifrequency and Full-Polarimetric SAR Assessment for Estimating Above Ground Biomass and Leaf Area Index in the Amazon Várzea Wetlands“. Remote Sensing 10, Nr. 9 (25.08.2018): 1355. http://dx.doi.org/10.3390/rs10091355.
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The aim of this study is to evaluate the potential of multifrequency and Full-polarimetric Synthetic Aperture Radar (SAR) data for retrieving both Above Ground Biomass (AGB) and Leaf Area Index (LAI) in the Amazon floodplain forest environment. Two specific questions were proposed: (a) Does multifrequency SAR data perform more efficiently than single-frequency data in estimating LAI and AGB of várzea forests?; and (b) Are quad-pol SAR data more efficient than single- and dual-pol SAR data in estimating LAI and AGB of várzea forest? To answer these questions, data from different sources (TerraSAR-X Multi Look Ground Range Detected (MGD), Radarsat-2 Standard Qual-Pol, advanced land observing satellite (ALOS)/ phased-arrayed L-band SAR (PALSAR-1). Fine-beam dual (FDB) and quad Polarimetric mode) were combined in 10 different scenarios to model both LAI and AGB. A R-platform routine was implemented to automatize the selection of the best regression models. Results indicated that ALOS/PALSAR variables provided the best estimates for both LAI and AGB. Single-frequency L-band data was more efficient than multifrequency SAR. PALSAR-FDB HV-dB provided the best LAI estimates during low-water season. The best AGB estimates at high-water season were obtained by PALSAR-1 quad-polarimetric data. The top three features for estimating AGB were proportion of volumetric scattering and both the first and second dominant phase difference between trihedral and dihedral scattering, extracted from Van Zyl and Touzi decomposition, respectively. The models selected for both AGB and LAI were parsimonious. The Root Mean Squared Error (RMSEcv), relative overall RMSEcv (%) and R2 value for LAI were 0.61%, 0.55% and 13%, respectively, and for AGB, they were 74.6 t·ha−1, 0.88% and 46%, respectively. These results indicate that L-band (ALOS/PALSAR-1) has a high potential to provide quantitative and spatial information about structural forest attributes in floodplain forest environments. This potential may be extended not only with PALSAR-2 data but also to forthcoming missions (e.g., NISAR, Global Ecosystems Dynamics Investigation Lidar (GEDI), BIOMASS, Tandem-L) for promoting wall-to-wall AGB mapping with a high level of accuracy in dense tropical forest regions worldwide.
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Beiranvand Pour, Amin, und Mazlan Hashim. „APPLICATION OF PALSAR-2 REMOTE SENSING DATA FOR LANDSLIDE HAZARD MAPPING IN KELANTAN RIVER BASIN, PENINSULAR MALAYSIA“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (23.06.2016): 413–16. http://dx.doi.org/10.5194/isprsarchives-xli-b8-413-2016.
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Yearly, several landslides ensued during heavy monsoons rainfall in Kelantan river basin, peninsular Malaysia, which are obviously connected to geological structures and topographical features of the region. In this study, the recently launched Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) onboard the Advanced Land Observing Satellite-2 (ALOS-2), remote sensing data were used to map geological structural and topographical features in the Kelantan river basin for identification of high potential risk and susceptible zones for landslides. Adaptive Local Sigma filter was selected and applied to accomplish speckle reduction and preserving both edges and features in PALSAR-2 fine mode observation images. Different polarization images were integrated to enhance geological structures. Additionally, directional filters were applied to the PALSAR-2 Local Sigma resultant image for edge enhancement and detailed identification of linear features. Several faults, drainage patterns and lithological contact layers were identified at regional scale. In order to assess the results, fieldwork and GPS survey were conducted in the landslide affected zones in the Kelantan river basin. Results demonstrate the most of the landslides were associated with N-S, NNW-SSE and NE-SW trending faults, angulated drainage pattern and metamorphic and Quaternary units. Consequently, structural and topographical geology maps were produced for Kelantan river basin using PALSAR-2 data, which could be broadly applicable for landslide hazard mapping.
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Beiranvand Pour, Amin, und Mazlan Hashim. „APPLICATION OF PALSAR-2 REMOTE SENSING DATA FOR LANDSLIDE HAZARD MAPPING IN KELANTAN RIVER BASIN, PENINSULAR MALAYSIA“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (23.06.2016): 413–16. http://dx.doi.org/10.5194/isprs-archives-xli-b8-413-2016.
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Yearly, several landslides ensued during heavy monsoons rainfall in Kelantan river basin, peninsular Malaysia, which are obviously connected to geological structures and topographical features of the region. In this study, the recently launched Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) onboard the Advanced Land Observing Satellite-2 (ALOS-2), remote sensing data were used to map geological structural and topographical features in the Kelantan river basin for identification of high potential risk and susceptible zones for landslides. Adaptive Local Sigma filter was selected and applied to accomplish speckle reduction and preserving both edges and features in PALSAR-2 fine mode observation images. Different polarization images were integrated to enhance geological structures. Additionally, directional filters were applied to the PALSAR-2 Local Sigma resultant image for edge enhancement and detailed identification of linear features. Several faults, drainage patterns and lithological contact layers were identified at regional scale. In order to assess the results, fieldwork and GPS survey were conducted in the landslide affected zones in the Kelantan river basin. Results demonstrate the most of the landslides were associated with N-S, NNW-SSE and NE-SW trending faults, angulated drainage pattern and metamorphic and Quaternary units. Consequently, structural and topographical geology maps were produced for Kelantan river basin using PALSAR-2 data, which could be broadly applicable for landslide hazard mapping.
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Natsuaki, Ryo, Takuma Anahara, Tsuyoshi Kotoura, Yuudai Iwatsuka, Naoya Tomii, Hiroyuki Katayama und Takeshi Nishihata. „Synthetic Aperture Radar Interferometry for Disaster Monitoring of Harbor Facilities“. Journal of Disaster Research 12, Nr. 3 (29.05.2017): 526–35. http://dx.doi.org/10.20965/jdr.2017.p0526.
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In this paper, we present experimental results of the disaster monitoring of harbor facilities using spaceborne synthetic aperture radar interferometry (InSAR). The Advanced Land Observing Satellite-2 (ALOS-2 or DAICHI-2), operated by the Japan Aerospace Exploration Agency (JAXA), carries the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2). PALSAR-2 can observe disaster areas day and night, in any weather, at a resolution of approximately 3 m. ALOS-2 PALSAR-2 has been used to measure large-scale ground deformation e.g., after earthquakes and volcanic eruptions. However, its robustness for smaller targets, such as harbor facilities, has not yet been substantiated. Here, we measured the uplift of a breakwater model made of concrete armor units, and confirmed the sensor accuracy to be better than 2 cm standard deviation. We also analyzed the damage to the Nagata and Suma ports in Kobe city, Hyogo prefecture, Japan hit by the 11th Typhoon in 2014, and detected the damaged area using interferometric coherence analysis.
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Jaya, Ni Made Pertiwi, und Fusanori Miura. „Extraction of Tsunami Damaged Areas Due to the 2010 Chile Earthquake Using Optical and SAR Data of ALOS“. International Journal of Environment and Geosciences 2, Nr. 2 (01.12.2018): 66. http://dx.doi.org/10.24843/ijeg.2018.v02.i02.p02.
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Information about damage areas is important due to the large-scale disasters worldwide. In the last decade, both optical and SAR remote sensing were applied in many disaster researches, such as tsunami damage detection. In this study, the ALOS AVNIR-2 and PALSAR images are used to extract the damaged areas caused by the 2010 Chile earthquake. In the processing of ALOS/AVNIR-2, the inundation area was estimated based on the NDVI calculation and classification. Furthermore, damaged areas of the ALOS/PALSAR are extracted by integrating the AVNIR-2 image for water mask and the DEM image for elevation mask. The damaged area result of AVNIR-2 is 8.91 Km2 and for the PALSAR is 8.72 Km2 that is along the coastal areas. The image results showed a good agreement and corresponding area according to the institutional map of the inundation area. Future study in another area is needed in order to strengthen the processing method.
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MIYAGI, Yousuke, Masanobu SHIMADA und Taku OZAWA. „Disaster Monitoring Using ALOS/PALSAR Data“. TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, SPACE TECHNOLOGY JAPAN 7, ists26 (2009): Tn_17—Tn_20. http://dx.doi.org/10.2322/tstj.7.tn_17.
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SHIMADA, Masanobu, und Shinichi SUZUKI. „ALOS-2 PALSAR-2 MISSION STATUS“. Journal of the Japan society of photogrammetry and remote sensing 54, Nr. 1 (2015): 41–45. http://dx.doi.org/10.4287/jsprs.54.41.
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Samsonov, Sergey. „Topographic Correction for ALOS PALSAR Interferometry“. IEEE Transactions on Geoscience and Remote Sensing 48, Nr. 7 (Juli 2010): 3020–27. http://dx.doi.org/10.1109/tgrs.2010.2043739.
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Truong, Hoang, Cao, Hayashi, Tadono und Nasahara. „JAXA Annual Forest Cover Maps for Vietnam during 2015–2018 Using ALOS-2/PALSAR-2 and Auxiliary Data“. Remote Sensing 11, Nr. 20 (17.10.2019): 2412. http://dx.doi.org/10.3390/rs11202412.
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Monitoring the temporal changes of forests is important for sustainable forest management. In this study, we investigated the potential of using multi-temporal synthetic aperture radar (SAR) images for mapping annual change in forest cover at a national scale. We assessed the robustness of using multi-temporal Phased Array L-band Synthetic Aperture Radar-2/Scanning Synthetic Aperture Radar (PALSAR-2/ScanSAR) mosaic images for forest mapping by comparison with single-temporal PALSAR-2 mosaic images for three test sites in North, Central, and Southern Vietnam. We then used a combination of multi-temporal PALSAR-2/ScanSAR images, multi-temporal Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) images, and Shuttle Radar Topography Mission (SRTM) images to map annual forest cover for mainland Vietnam during 2015–2018. Average overall accuracies of our forest/non-forest (FNF) maps (86.6% ± 3.1%) were greater than recent maps of Japan Aerospace Exploration Agency (JAXA, (77.5% ± 3.2%)) and European Space Agency (ESA, (85.4% ± 1.6%)). Our estimates of mainland Vietnam’s forest area were close to that of the Vietnamese government. A comparison of the spatial distribution of forest estimated from JAXA and ESA FNF maps showed that our FNF map in 2015 agreed relatively well with the ESA map, with 77% of pixels being consistent. This study demonstrates the merit of using multi-temporal PALSAR-2/ScanSAR images for annual forest mapping at a national scale.
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Yang, Zhiqi, Jinwei Dong, Yuanwei Qin, Wenjian Ni, Guosong Zhao, Wei Chen, Bangqian Chen, Weili Kou, Jie Wang und Xiangming Xiao. „Integrated Analyses of PALSAR and Landsat Imagery Reveal More Agroforests in a Typical Agricultural Production Region, North China Plain“. Remote Sensing 10, Nr. 9 (21.08.2018): 1323. http://dx.doi.org/10.3390/rs10091323.
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As the largest among terrestrial ecosystems, forests are vital to maintaining ecosystem services and regulating regional climate. The area and spatial distribution of trees in densely forested areas have been focused on in the past few decades, while sparse forests in agricultural zones, so-called agroforests or trees outside forests (TOF), have usually been ignored or missed in existing forest mapping efforts, despite their important role in regulating agricultural ecosystems. We combined Landsat and PALSAR data to map forests in a typical agricultural zone in the North China Plain. The resultant map, based on PALSAR and Landsat (PL) data, was also compared with five existing medium resolution (30–100 m) forest maps from PALSAR (JAXA forest map) and Landsat: NLCD-China, GlobeLand30, ChinaCover, and FROM-GLC. The results show that the PL-based forest map has the highest accuracy (overall accuracy of 95 ± 1% with a 95% confidence interval, and Kappa coefficient of 0.86) compared to those forest maps based on single Landsat or PALSAR data in the North China Plain (overall accuracy ranging from 85 ± 2% to 92 ± 1%). All forest maps revealed higher accuracy in densely forested mountainous areas, while the PL-based and JAXA forest maps showed higher accuracy in the plain, as the higher omission errors existed in only the Landsat-based forest maps. Moreover, we found that the PL-based forest map can capture more patched forest information in low forest density areas. This means that the radar data have advantages in capturing forests in the typical agricultural zones, which tend to be missing in published Landsat-based only forest maps. Given the significance of agroforests in regulating ecosystem services of the agricultural ecosystem and improving carbon stock estimation, this study implies that the integration of PALSAR and Landsat data can provide promising agroforest estimates in future forest inventory efforts, targeting a comprehensive understanding of ecosystem services of agroforests and a more accurate carbon budget inventory.
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Vasil'Chuk, Yurij K., und Alla C. Vasil'Chuk. „The 14C Age of Palsas in Northern Eurasia“. Radiocarbon 40, Nr. 2 (1997): 895–904. http://dx.doi.org/10.1017/s0033822200018865.
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We discuss results of 14C dating peat of palsa of different regions of Northern Eurasia. We apply these dates to determine the age of active palsa growth during different periods of the Holocene in permafrost zone.
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Shakya, A. K., A. Ramola, A. Kandwal und R. Prakash. „COMPARISON OF SUPERVISED CLASSIFICATION TECHNIQUES WITH ALOS PALSAR SENSOR FOR ROORKEE REGION OF UTTARAKHAND, INDIA“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-5 (19.11.2018): 693–701. http://dx.doi.org/10.5194/isprs-archives-xlii-5-693-2018.
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<p><strong>Abstract.</strong> The Advanced Land Observing Satellite (ALOS) is developed by the Japanese Aerospace Exploration Agency (JAXA) which was launched in the year 2006 for the Earth observation and exploration purpose. The ALOS was carrying PRISM, AVNIR-2 and PALSAR sensors for this purpose. PALSAR is L-Band synthetic aperture radar (SAR). The PALSAR sensor is designed in a way that it can work in all weather conditions with a resolution of 10 meters. In this research work we have made an investigation on the accuracy obtained from the various supervised classification techniques. We have compared the accuracy obtained by classifying the ALOS PALSAR data of the Roorkee region of Uttarakhand, India. The training ROI’S (Region of Interest) are created manually with the assistance of ArcGIS Earth and for the testing purpose, we have used the Global positioning system (GPS) coordinates of the region. Supervised classification techniques included in this comparison are Parallelepiped classification (PC), Minimum distance classification (MDC), Mahalanobis distance classification (MaDC), Maximum likelihood classification (MLC), Spectral angle mapper (SAM), Spectral information divergence (SID) and Support vector machine (SVM). Later, through the post classification confusion matrix accuracy assessment test is performed and the corresponding value of the kappa coefficient is obtained. In the result, we have concluded MDC as best in term of overall accuracy with 82.3634% and MLC with a kappa value of 0.7591. Finally, a peculiar relationship is developed in between classification accuracy and kappa coefficient.</p>
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Yamada, Y. „CROP SPECIES RECOGNITION AND DISCRIMINATION PADDY-RICE-GROWINGFIELDS FROM REAPED-FIELDS BY THE RADAR VEGETATION INDEX (RVI) OF ALOS-2/PALSAR2“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (24.06.2016): 1083–87. http://dx.doi.org/10.5194/isprs-archives-xli-b8-1083-2016.
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The Japanese ALOS-2 satellite was launched on May 24<sup>th</sup>, 2014. It has the L-band SAR, PALSAR-2. Kim,Y. and van Zyl, J.J. proposed a kind of Radar Vegetation Index (RVI) as RVI = 8 * σ<sup>0</sup><sub>hv</sub> / (σ<sup>0</sup><sub>hh</sub> + σ<sup>0</sup><sub>vv</sub> + 2* σ<sup>0</sup><sub>hv</sub>) by L-band full-polarimetric radar data. Kim, Y. and Jackson, T.J., et al. applied the equation into rice and soybean by multi-frequency polarimetric scatterometer above 4.16 meters from the ground. Their report showed the L-band was the most promising wave length for estimating LAI and NDVI from RVI. The author tried to apply the analysis to the actual paddy field areas, both Inashiki region and Miyagi region in the eastern main island, “Honshu”, areas of Japan by ALOS-2/PALSAR-2 full-polarimetry data in the summer season, the main crop growing time, of 2015. Judging from conventional methods, it will be possible to discriminate paddy rice growing fields from reaped fields or the other crops growing fields by the PALSAR-2 data. But the RVI value is vaguely related to such land use or biomass at the present preliminary experiment. The continuous research by the additional PALSAR-2 full-polarimetry data should be desired.