Zeitschriftenartikel zum Thema „Satellite stereoscopic imagery“
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Kim, Minseok, Jhoon Kim, Hyunkwang Lim, Seoyoung Lee, Yeseul Cho, Huidong Yeo und Sang-Woo Kim. „Exploring geometrical stereoscopic aerosol top height retrieval from geostationary satellite imagery in East Asia“. Atmospheric Measurement Techniques 16, Nr. 10 (31.05.2023): 2673–90. http://dx.doi.org/10.5194/amt-16-2673-2023.
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Abstract. Despite the importance of aerosol height information for events such as volcanic eruptions and long-range aerosol transport, spatial coverage of its retrieval is often limited because of a lack of appropriate instruments and algorithms. Geostationary satellite observations in particular provide constant monitoring for such events. This study assessed the application of different viewing geometries for a pair of geostationary imagers to retrieve aerosol top height (ATH) information. The stereoscopic algorithm converts a lofted aerosol layer parallax, calculated using image-matching of two visible images, to ATH. The sensitivity study provides a reliable result using a pair of Advanced Himawari Imager (AHI) and Advanced Geostationary Radiation Imager (AGRI) images at 40∘ longitudinal separation. The pair resolved aerosol layers above 1 km altitude over East Asia. In contrast, aerosol layers must be above 3 km for a pair of AHI and Advanced Meteorological Imager (AMI) images at 12.5∘ longitudinal separation to resolve their parallax. Case studies indicate that the stereoscopic ATH retrieval results are consistent with aerosol heights determined using extinction profiles from the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP). Comparisons between the stereoscopic ATH and the CALIOP 90 % extinction height, defined by extinction coefficient at 532 nm data, indicated that 88.9 % of ATH estimates from the AHI and AGRI are within 2 km of CALIOP 90 % extinction heights, with a root-mean-squared difference (RMSD) of 1.66 km. Meanwhile, 24.4 % of ATH information from the AHI and AMI was within 2 km of the CALIOP 90 % extinction height, with an RMSD of 4.98 km. The ability of the stereoscopic algorithm to monitor hourly aerosol height variations is demonstrated by comparison with a Korea Aerosol Lidar Observation Network dataset.
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Neto, F. A. „FIRST RESULTS ON ORIENTING SIMULATED ALONG-TRACK SATELLITE STEREOSCOPIC IMAGERY“. Photogrammetric Record 14, Nr. 81 (April 1993): 439–46. http://dx.doi.org/10.1111/j.1477-9730.1993.tb00273.x.
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Kornus, W., A. Magariños, M. Pla, E. Soler und F. Perez. „PHOTOGRAMMETRIC PROCESSING USING ZY-3 SATELLITE IMAGERY“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-3/W2 (10.03.2015): 109–13. http://dx.doi.org/10.5194/isprsarchives-xl-3-w2-109-2015.
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This paper evaluates the stereoscopic capacities of the Chinese sensor ZiYuan-3 (ZY-3) for the generation of photogrammetric products. The satellite was launched on January 9, 2012 and carries three high-resolution panchromatic cameras viewing in forward (22º), nadir (0º) and backward direction (-22º) and an infrared multi-spectral scanner (IRMSS), which is slightly looking forward (6º). The ground sampling distance (GSD) is 2.1m for the nadir image, 3.5m for the two oblique stereo images and 5.8m for the multispectral image. The evaluated ZY-3 imagery consists of a full set of threefold-stereo and a multi-spectral image covering an area of ca. 50km x 50km north-west of Barcelona, Spain. The complete photogrammetric processing chain was executed including image orientation, the generation of a digital surface model (DSM), radiometric image correction, pansharpening, orthoimage generation and digital stereo plotting. <br><br> All 4 images are oriented by estimating affine transformation parameters between observed and nominal RPC (rational polynomial coefficients) image positions of 17 ground control points (GCP) and a subsequent calculation of refined RPC. From 10 independent check points RMS errors of 2.2m, 2.0m and 2.7m in X, Y and H are obtained. Subsequently, a DSM of 5m grid spacing is generated fully automatically. A comparison with the Lidar data results in an overall DSM accuracy of approximately 3m. In moderate and flat terrain higher accuracies in the order of 2.5m and better are achieved. In a next step orthoimages from the high resolution nadir image and the multispectral image are generated using the refined RPC geometry and the DSM. After radiometric corrections a fused high resolution colour orthoimage with 2.1m pixel size is created using an adaptive HSL method. The pansharpen process is performed after the individual geocorrection due to the different viewing angles between the two images. In a detailed analysis of the colour orthoimage artifacts are detected covering an area of 4691ha, corresponding to less than 2% of the imaged area. Most of the artifacts are caused by clouds (4614ha). A minor part (77ha) is affected by colour patch, stripping or blooming effects. <br><br> For the final qualitative analysis on the usability of the ZY-3 imagery for stereo plotting purposes stereo combinations of the nadir and an oblique image are discarded, mainly due to the different pixel size, which produces difficulties in the stereoscopic vision and poor accuracy in positioning and measuring. With the two oblique images a level of detail equivalent to 1:25.000 scale is achieved for transport network, hydrography, vegetation and elements to model the terrain as break lines. For settlement, including buildings and other constructions a lower level of detail is achieved equivalent to 1:50.000 scale.
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Lodwick, G. D., und S. H. Paine. „SATELLITE REMOTE SENSING IN SURVEYING PRESENT OPPORTUNITIES, FUTURE POSSIBILITIES“. Canadian Surveyor 40, Nr. 3 (September 1986): 315–26. http://dx.doi.org/10.1139/tcs-1986-0025.
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Of all the areas of the earth sciences affected by satellite remote sensing, the surveying profession has been one of the last to take advantage of its unique features. This is due in part to: resolution limitations of Landsat 1, 2 and 3, difficulties in registration and positioning of the imagery, technical constraints in handling vast quantities of digital data, and the excellent methods currently available for the production of cartographic products. Nevertheless, satellite remote sensing has now emerged as a complementary procedure to many existing techniques utilized in surveying and mapping. Already, Landsat is being used for topographic mapping, hydrographic surveying and resource mapping purposes. However, with the improved resolution of Landsat 4, the potential of stereoscopic coverage with the SPOT satellites and present developments in computer processing and data manipulation, satellite remote sensing in the next decade will emerge as an indispensable tool for mapping and cartography.
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Almeida, Luís, Rafael Almar, Erwin Bergsma, Etienne Berthier, Paulo Baptista, Erwan Garel, Olusegun Dada und Bruna Alves. „Deriving High Spatial-Resolution Coastal Topography From Sub-meter Satellite Stereo Imagery“. Remote Sensing 11, Nr. 5 (12.03.2019): 590. http://dx.doi.org/10.3390/rs11050590.
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High spatial resolution coastal Digital Elevation Models (DEMs) are crucial to assess coastal vulnerability and hazards such as beach erosion, sedimentation, or inundation due to storm surges and sea level rise. This paper explores the possibility to use high spatial-resolution Pleiades (pixel size = 0.7 m) stereoscopic satellite imagery to retrieve a DEM on sandy coastline. A 40-km coastal stretch in the Southwest of France was selected as a pilot-site to compare topographic measurements obtained from Pleiades satellite imagery, Real Time Kinematic GPS (RTK-GPS) and airborne Light Detection and Ranging System (LiDAR). The derived 2-m Pleiades DEM shows an overall good agreement with concurrent methods (RTK-GPS and LiDAR; correlation coefficient of 0.9), with a vertical Root Mean Squared Error (RMS error) that ranges from 0.35 to 0.48 m, after absolute coregistration to the LiDAR dataset. The largest errors (RMS error > 0.5 m) occurred in the steep dune faces, particularly at shadowed areas. This work shows that DEMs derived from sub-meter satellite imagery capture local morphological features (e.g., berm or dune shape) on a sandy beach, over a large spatial domain.
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Rayne, Louise, und Daniel Donoghue. „A Remote Sensing Approach for Mapping the Development of Ancient Water Management in the Near East“. Remote Sensing 10, Nr. 12 (14.12.2018): 2042. http://dx.doi.org/10.3390/rs10122042.
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We present a novel approach that uses remote sensing to record and reconstruct traces of ancient water management throughout the whole region of Northern Mesopotamia, an area where modern agriculture and warfare has had a severe impact on the survival of archaeological remains and their visibility in modern satellite imagery. However, analysis and interpretation of declassified stereoscopic spy satellite data from the 1960s and early 1970s revealed traces of ancient water management systems. We processed satellite imagery to facilitate image interpretation and used photogrammetry to reconstruct hydraulic pathways. Our results represent the first comprehensive map of water management features across the entirety of Northern Mesopotamia for the period ca. 1200 BC to AD 1500. In particular, this shows that irrigation was widespread throughout the region in the Early Islamic period, including within the zone traditionally regarded as “rain-fed”. However, we found that a high proportion of the ancient canal systems had been damaged or destroyed by 20th century changes to agricultural practices and land use. Given this, there is an urgent need to record these rapidly vanishing water management systems that were an integral part of the ancient agricultural landscape and that underpinned powerful states.
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Tack, Frederik, Rudi Goossens und Gurcan Buyuksalih. „Assessment of a Photogrammetric Approach for Urban DSM Extraction from Tri-Stereoscopic Satellite Imagery“. Photogrammetric Record 27, Nr. 139 (September 2012): 293–310. http://dx.doi.org/10.1111/j.1477-9730.2012.00691.x.
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Mueller, Kevin J., Dong L. Wu, Ákos Horváth, Veljko M. Jovanovic, Jan-Peter Muller, Larry Di Girolamo, Michael J. Garay, David J. Diner, Catherine M. Moroney und Steve Wanzong. „Assessment of MISR Cloud Motion Vectors (CMVs) Relative to GOES and MODIS Atmospheric Motion Vectors (AMVs)“. Journal of Applied Meteorology and Climatology 56, Nr. 3 (März 2017): 555–72. http://dx.doi.org/10.1175/jamc-d-16-0112.1.
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AbstractCloud motion vector (CMV) winds retrieved from the Multiangle Imaging SpectroRadiometer (MISR) instrument on the polar-orbiting Terra satellite from 2003 to 2008 are compared with collocated atmospheric motion vectors (AMVs) retrieved from Geostationary Operational Environmental Satellite (GOES) imagery over the tropics and midlatitudes and from Moderate Resolution Imaging Spectroradiometer (MODIS) imagery near the poles. MISR imagery from multiple view angles is exploited to jointly retrieve stereoscopic cloud heights and motions, showing advantages over the AMV heights assigned by radiometric means, particularly at low heights (<3 km) that account for over 95% of MISR CMV sampling. MISR–GOES wind differences exhibit a standard deviation ranging with increasing height from 3.3 to 4.5 m s−1 for a high-quality [quality indicator (QI) ≥ 80] subset where height differences are <1.5 km. Much of the observed difference can be attributed to the less accurately retrieved component of CMV motion along the direction of satellite motion. MISR CMV retrieval is subject to correlation between error in retrieval of this along-track component and of height. This manifests as along-track bias varying with height to magnitudes as large as 2.5 m s−1. The cross-track component of MISR CMVs shows small (<0.5 m s−1) bias and standard deviation of differences (1.7 m s−1) relative to GOES AMVs. Larger differences relative to MODIS are attributed to the tracking of cloud features at heights lower than MODIS in multilayer cloud scenes.
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Giles, Philip T., Michael A. Chapman und Steven E. Franklin. „Incorporation of a digital elevation model derived from stereoscopic satellite imagery in automated terrain analysis“. Computers & Geosciences 20, Nr. 4 (Mai 1994): 441–60. http://dx.doi.org/10.1016/0098-3004(94)90078-7.
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Dowdeswell, J. A., M. R. Gorman, Yu Ya Macheret, M. Yu Moskalevsky und J. O. Hagen. „Digital comparison of high resolution Sojuzkarta KFA-1000 imagery of ice masses with Landsat and SPOT data“. Annals of Glaciology 17 (1993): 105–12. http://dx.doi.org/10.3189/s0260305500012684.
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Russian satellite imagery of the polar regions has recently become available to western scientists through Sojuzkarta. The KFA-1000 photographic camera is of particular interest to glaciologists due to its high resolution (a nominal 5 m). Digitized photographic products from this instrument are compared with digital data from Landsat and SPOT series satellites for a partly glacierized area of northwest Spitsbergen. Comparison of KFA-1000 data with detailed maps of man-made structures at the settlement of Ny Ålesund demonstrates that the resolution of the photographic imagery is about 3 m, but scanner resolution limited our digital data to about 6 m. Significantly less detail can be resolved on Landsat TM imagery and Landsat MSS data fail to resolve any of the structures. KFA-1000 data are compared with Landsat TM and MSS images and SPOT HRV multispectral imagery for several tidewater glaciers in Spitsbergen. KFA-1000 imagery is of a significantly higher geometric resolution than the other sensors, allowing the clear identification of individual crevasses and other ice surface features. KFA-1000 scenes from 1985 and 1988 are used to measure ice marginal fluctuations for several northwest Spitsbergen glaciers, and the onset of a surge can also be identified. This imagery has a 60% overlap between scenes and the heighting accuracy of the stereoscopic data is calculated at 45 m. Radiometric analysis of KFA-1000 data is restricted to relative brightness values, since no absolute calibration is available. The photographic products appear speckled, and the range and standard deviation of normalized pixel brightness values over snow is greater than for equivalent Landsat TM data. The very high spatial resolution of the KFA-1000 camera is its principal attraction for glaciologists.
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Dowdeswell, J. A., M. R. Gorman, Yu Ya Macheret, M. Yu Moskalevsky und J. O. Hagen. „Digital comparison of high resolution Sojuzkarta KFA-1000 imagery of ice masses with Landsat and SPOT data“. Annals of Glaciology 17 (1993): 105–12. http://dx.doi.org/10.1017/s0260305500012684.
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Russian satellite imagery of the polar regions has recently become available to western scientists through Sojuzkarta. The KFA-1000 photographic camera is of particular interest to glaciologists due to its high resolution (a nominal 5 m). Digitized photographic products from this instrument are compared with digital data from Landsat and SPOT series satellites for a partly glacierized area of northwest Spitsbergen. Comparison of KFA-1000 data with detailed maps of man-made structures at the settlement of Ny Ålesund demonstrates that the resolution of the photographic imagery is about 3 m, but scanner resolution limited our digital data to about 6 m. Significantly less detail can be resolved on Landsat TM imagery and Landsat MSS data fail to resolve any of the structures. KFA-1000 data are compared with Landsat TM and MSS images and SPOT HRV multispectral imagery for several tidewater glaciers in Spitsbergen. KFA-1000 imagery is of a significantly higher geometric resolution than the other sensors, allowing the clear identification of individual crevasses and other ice surface features. KFA-1000 scenes from 1985 and 1988 are used to measure ice marginal fluctuations for several northwest Spitsbergen glaciers, and the onset of a surge can also be identified. This imagery has a 60% overlap between scenes and the heighting accuracy of the stereoscopic data is calculated at 45 m. Radiometric analysis of KFA-1000 data is restricted to relative brightness values, since no absolute calibration is available. The photographic products appear speckled, and the range and standard deviation of normalized pixel brightness values over snow is greater than for equivalent Landsat TM data. The very high spatial resolution of the KFA-1000 camera is its principal attraction for glaciologists.
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Bessin, Zoé, Marion Jaud, Pauline Letortu, Emmanuel Vassilakis, Niki Evelpidou, Stéphane Costa und Christophe Delacourt. „Smartphone Structure-from-Motion Photogrammetry from a Boat for Coastal Cliff Face Monitoring Compared with Pléiades Tri-Stereoscopic Imagery and Unmanned Aerial System Imagery“. Remote Sensing 15, Nr. 15 (31.07.2023): 3824. http://dx.doi.org/10.3390/rs15153824.
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Many issues arise from the recession of sea cliffs, including threats to coastal communities and infrastructure. The best proxy to study cliff instability processes is the cliff face evolution. Unfortunately, due to its verticality, this proxy is difficult to observe and measure. This study proposed and compared three remote sensing methods based on structure-from-motion (SfM) photogrammetry or stereorestitution: boat-based SfM photogrammetry with smartphones, unmanned aerial system (UAS) or unmanned aerial vehicle (UAV) photogrammetry with centimetric positioning and Pléiades tri-stereo imagery. An inter-comparison showed that the mean distance between the point clouds produced by the different methods was about 2 m. The satellite approach had the advantage of covering greater distances. The SfM photogrammetry approach from a boat allowed for a better reconstruction of the cliff foot (especially in the case of overhangs). However, over long distances, significant geometric distortions affected the method. The UAS with centimetric positioning offered a good compromise, but flight autonomy limited the extent of the monitored area. SfM photogrammetry from a boat can be used as an initial estimate for risk management services following a localized emergency. For long-term monitoring of the coastline and its evolution, satellite photogrammetry is recommended.
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Chandelier, L., L. Coeurdevey, S. Bosch, P. Favé, R. Gachet, A. Orsoni, T. Tilak und A. Barot. „A WORLDWIDE 3D GCP DATABASE INHERITED FROM 20 YEARS OF MASSIVE MULTI-SATELLITE OBSERVATIONS“. ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences V-2-2020 (03.08.2020): 15–23. http://dx.doi.org/10.5194/isprs-annals-v-2-2020-15-2020.
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Abstract. High location accuracy is a major requirement for satellite image users. Target performance is usually achieved thanks to either specific on-board satellite equipment or an auxiliary registration reference dataset. Both methods may be expensive and with certain limitations in terms of performance. The Institut national de l’information géographique et forestière (IGN) and Airbus Defence and Space (ADS) have worked together for almost 20 years, to build reference data for improving image location using multi-satellite observations. The first geometric foundation created has mainly used SPOT 5 High Resolution Stereoscopic (HRS) imagery, ancillary Ground Control Points (GCP) and Very High Resolution (VHR) imagery, providing a homogenous location accuracy of 10m CE90 almost all over the world in 2010.Space Reference Points (SRP) is a new worldwide 3D GCP database, built from a plethoric SPOT 6/7 multi-view archive, largely automatically processed, with cloud-based technologies. SRP aims at providing a systematic and reliable solution for image location (Unmanned Aerial Vehicle, VHR satellite imagery, High Altitudes Pseudo-Satellite…) and similar topics thanks to a high-density point distribution with a 3m CE90 accuracy.This paper describes the principle of SRP generation and presents the first validation results. A SPOT 6/7 smart image selection is performed to keep only relevant images for SRP purpose. The location of these SPOT 6/7 images is refined thanks to a spatiotriangulation on the worldwide geometric foundation, itself improved where needed. Points making up the future SRP database are afterward extracted thanks to classical feature detection algorithms and with respect to the expected density. Different filtering methods are applied to keep the best candidates. The last step of the processing chain is the formatting of the data to the delivery format, including metadata. An example of validation of SRP concept and specification on two tests sites (Spain and China) is then given. As a conclusion, the on-going production is shortly presented.
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Casassa, Gino, Katrine Smith, Andrés Rivera, José Araos, Michael Schnirch und Christoph Schneider. „Inventory of glaciers in isla Riesco, Patagonia, Chile, based on aerial photography and satellite imagery“. Annals of Glaciology 34 (2002): 373–78. http://dx.doi.org/10.3189/172756402781817671.
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AbstractA glacier inventory for península Córdova, isla Riesco, Chilean Patagonia (53°14’ S, 73°00’W), has been compiled based on stereoscopic interpretation of aerial photographs of March and December 1984 and 1:100 000 topographic maps. Three small icefields comprising 33 glacier outlets, in addition to 12 small separate glaciers, have been identified, with a total area of 57 km2. Glaciers are located on mountain peaks with a maximum altitude of 1183 mand a lowermost elevation of 100 m. All glaciers terminate on land, except for three glaciers calving into small fresh-water lakes. A Landsat Thematic Mapper (TM) image of 6 October 1986 has been rectified and analyzed using a supervised classification to estimate snow- and glacier-covered surfaces. Glacier-area data derived from satellite-image analyses have been adjusted at península Córdova using photo-interpreted data, and extrapolated to estimate a glacier area of 215 ±40km2 for all of isla Riesco. The presence of trimlines and moraines beyond the present position of the glaciers indicates a generalized retreat from a maximum neoglacial position at península Córdova, most probably as a result of regional warming and precipitation decrease observed during the last century.
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Belart, Joaquín M. C., Etienne Berthier, Eyjólfur Magnússon, Leif S. Anderson, Finnur Pálsson, Thorsteinn Thorsteinsson, Ian M. Howat, Guðfinna Aðalgeirsdóttir, Tómas Jóhannesson und Alexander H. Jarosch. „Winter mass balance of Drangajökull ice cap (NW Iceland) derived from satellite sub-meter stereo images“. Cryosphere 11, Nr. 3 (30.06.2017): 1501–17. http://dx.doi.org/10.5194/tc-11-1501-2017.
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Abstract. Sub-meter resolution, stereoscopic satellite images allow for the generation of accurate and high-resolution digital elevation models (DEMs) over glaciers and ice caps. Here, repeated stereo images of Drangajökull ice cap (NW Iceland) from Pléiades and WorldView2 (WV2) are combined with in situ estimates of snow density and densification of firn and fresh snow to provide the first estimates of the glacier-wide geodetic winter mass balance obtained from satellite imagery. Statistics in snow- and ice-free areas reveal similar vertical relative accuracy (< 0.5 m) with and without ground control points (GCPs), demonstrating the capability for measuring seasonal snow accumulation. The calculated winter (14 October 2014 to 22 May 2015) mass balance of Drangajökull was 3.33 ± 0.23 m w.e. (meter water equivalent), with ∼ 60 % of the accumulation occurring by February, which is in good agreement with nearby ground observations. On average, the repeated DEMs yield 22 % less elevation change than the length of eight winter snow cores due to (1) the time difference between in situ and satellite observations, (2) firn densification and (3) elevation changes due to ice dynamics. The contributions of these three factors were of similar magnitude. This study demonstrates that seasonal geodetic mass balance can, in many areas, be estimated from sub-meter resolution satellite stereo images.
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Molochko, Anna Vyacheslavovna, Tatiana Valerievna Pyatnizyna, Aleksey Vasilievich Fedorov und Dmitriy Pavlovich Khvorostukhin. „Methodic of Stereoscopic Terrain Model Creation Based on a Single Satellite (Space) Imagery by Means of Lens Raster“. Izvestiya of Saratov University. New Series. Series: Earth Sciences 14, Nr. 2 (2014): 21–25. http://dx.doi.org/10.18500/1819-7663-2014-14-2-21-25.
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Yu, Tianyu, Wenjian Ni, Zhiyu Zhang, Qinhuo Liu und Guoqing Sun. „Regional Sampling of Forest Canopy Covers Using UAV Visible Stereoscopic Imagery for Assessment of Satellite-Based Products in Northeast China“. Journal of Remote Sensing 2022 (10.01.2022): 1–14. http://dx.doi.org/10.34133/2022/9806802.
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Canopy cover is an important parameter affecting forest succession, carbon fluxes, and wildlife habitats. Several global maps with different spatial resolutions have been produced based on satellite images, but facing the deficiency of reliable references for accuracy assessments. The rapid development of unmanned aerial vehicle (UAV) equipped with consumer-grade camera enables the acquisition of high-resolution images at low cost, which provides the research community a promising tool to collect reference data. However, it is still a challenge to distinguish tree crowns and understory green vegetation based on the UAV-based true color images (RGB) due to the limited spectral information. In addition, the canopy height model (CHM) derived from photogrammetric point clouds has also been used to identify tree crowns but limited by the unavailability of understory terrain elevations. This study proposed a simple method to distinguish tree crowns and understories based on UAV visible images, which was referred to as BAMOS for convenience. The central idea of the BAMOS was the synergy of spectral information from digital orthophoto map (DOM) and structural information from digital surface model (DSM). Samples of canopy covers were produced by applying the BAMOS method on the UAV images collected at 77 sites with a size of about 1.0 km2 across Daxing’anling forested area in northeast of China. Results showed that canopy cover extracted by the BAMOS method was highly correlated to visually interpreted ones with correlation coefficient (r) of 0.96 and root mean square error (RMSE) of 5.7%. Then, the UAV-based canopy covers served as references for assessment of satellite-based maps, including MOD44B Version 6 Vegetation Continuous Fields (MODIS VCF), maps developed by the Global Land Cover Facility (GLCF) and by the Global Land Analysis and Discovery laboratory (GLAD). Results showed that both GLAD and GLCF canopy covers could capture the dominant spatial patterns, but GLAD canopy cover tended to miss scattered trees in highly heterogeneous areas, and GLCF failed to capture non-tree areas. Most important of all, obvious underestimations with RMSE about 20% were easily observed in all satellite-based maps, although the temporal inconsistency with references might have some contributions.
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Schuster, Mathieu, Claude Roquin, Abderamane Moussa, Jean-François Ghienne, Philippe Duringer, Frédéric Bouchette, Arnaud Durand und Bernard Allenbach. „shorelines of the Holocene Megalake Chad (Africa, Sahara) investigated with very high resolution satellite imagery (Pléiades) : example of the Goz Kerki paleo-spit“. Revue Française de Photogrammétrie et de Télédétection, Nr. 208 (05.09.2014): 63–68. http://dx.doi.org/10.52638/rfpt.2014.114.
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Megalake Chad (350,000 km2), the largest paleo-lake of the Sahara-Sahel area, is one of the most emblematic marker of the hydroclimatic changes that occurred during the African Humid Period (AHP; ca. 11,500 — 5,000 years BP) in subtropical Africa. From field surveys, the existence of Megalake Chad is well demonstrated by widespread typical lake deposits. However, considering the very large size of this paleo-lake, it is best evidenced and understood from space. Conspicuous paleo-littoral features distributed along hundreds of kilometers are clearly visible on second generation satellite images. These features represent major archives of the Megalake Chad and of the climate during the AHP. This paper is the first attempt to investigate the paleo-littoral of Megalake Chad with very high resolution satellite imagery. A Pléiades scene (images and DEM) is used to characterize the fossil sand spit of the Goz Kerki, which is one of the most representative and best preserved littoral features of Megalake Chad. Thanks to Pléiades stereoscopic images the geomorphology and the lithology of this paleo-spit can now be detailed and the evolution of the paleo-bathymetry of Megalake Chad can be reconstructed. This brings new insights into the paleo-environments and paleo-climates of the Sahara-Sahel region.
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Maas, A., M. Alrajhi, A. Alobeid und C. Heipke. „AUTOMATIC CLASSIFICATION OF HIGH RESOLUTION SATELLITE IMAGERY – A CASE STUDY FOR URBAN AREAS IN THE KINGDOM OF SAUDI ARABIA“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-1/W1 (30.05.2017): 11–16. http://dx.doi.org/10.5194/isprs-archives-xlii-1-w1-11-2017.
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Updating topographic geospatial databases is often performed based on current remotely sensed images. To automatically extract the object information (labels) from the images, supervised classifiers are being employed. Decisions to be taken in this process concern the definition of the classes which should be recognised, the features to describe each class and the training data necessary in the learning part of classification. With a view to large scale topographic databases for fast developing urban areas in the Kingdom of Saudi Arabia we conducted a case study, which investigated the following two questions: (a) which set of features is best suitable for the classification?; (b) what is the added value of height information, e.g. derived from stereo imagery? Using stereoscopic GeoEye and Ikonos satellite data we investigate these two questions based on our research on label tolerant classification using logistic regression and partly incorrect training data. We show that in between five and ten features can be recommended to obtain a stable solution, that height information consistently yields an improved overall classification accuracy of about 5%, and that label noise can be successfully modelled and thus only marginally influences the classification results.
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Gardner, A. S., G. Moholdt, A. Arendt und B. Wouters. „Long-term contributions of Baffin and Bylot Island Glaciers to sea level rise: an integrated approach using airborne and satellite laser altimetry, stereoscopic imagery and satellite gravimetry“. Cryosphere Discussions 6, Nr. 2 (26.04.2012): 1563–610. http://dx.doi.org/10.5194/tcd-6-1563-2012.
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Abstract. Canadian Arctic glaciers have recently contributed large volumes of meltwater to the world's oceans. To place recently observed glacier wastage into a historical perspective and to determine the region's longer-term (~50 years) contribution to sea level, we estimate mass and volume changes for the glaciers of Baffin and Bylot Islands using Digital Elevation Models generated from airborne and satellite stereoscopic imagery and elevation postings from repeat airborne and satellite laser altimetry. In addition, we update existing glacier mass change records from GRACE satellite gravimetry to cover the period from 2003 to 2011. Using an integrated approach we find that the rate of mass loss from the region's glaciers increased from 11.1 ± 1.8 Gt a−1 (–270 ± 40 kg m−2 a−1) in 1963–2006 to 23.8 ± 3.1 Gt a−1 (–580 ± 80 kg m2 a−1) in 2003–2011. The doubling of the rate of mass loss is attributed to higher temperatures in summer with little change in annual precipitation. Through both direct and indirect effects, changes in summer temperatures accounted for 68–98 % of the variance in the rate of mass loss to which the Barnes Ice Cap was found to be 1.6 times more sensitive than either the Penny Ice Cap or the regions glaciers as a whole. Between 2003 and 2011 the glaciers of Baffin and Bylot Islands contributed 0.07 ± 0.01 mm a−1 to sea level rise, a rate equivalent to the contribution coming from Patagonian glaciers. Over the 48-year period between 1963 and 2011 the glaciers of Baffin and Bylot Islands contributed 1.7 mm to the world's oceans.
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Dávila, Norma, Lucia Capra, Dolors Ferrés, Juan Carlos Gavilanes-Ruiz und Pablo Flores. „Chronology of the 2014–2016 Eruptive Phase of Volcán de Colima and Volume Estimation of Associated Lava Flows and Pyroclastic Flows Based on Optical Multi-Sensors“. Remote Sensing 11, Nr. 10 (16.05.2019): 1167. http://dx.doi.org/10.3390/rs11101167.
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The eruption at Volcán de Colima (México) on 10–11 July 2015 represents the most violent eruption that has occurred at this volcano since the 1913 Plinian eruption. The extraordinary runout of the associated pyroclastic flows was never observed during the past dome collapse events in 1991 or 2004–2005. Based on Satellite Pour l’Observation de la Terre (SPOT) and Earth Observing-1 (EO-1) ALI (Advanced Land Imager), the chronology of the different eruptive phases from September 2014 to September 2016 is reconstructed here. A digital image segmentation procedure allowed for the mapping of the trajectory of the lava flows emplaced on the main cone as well as the pyroclastic flow deposits that inundated the Montegrande ravine on the southern flank of the volcano. Digital surface models (DSMs) obtained from SPOT/6 dual-stereoscopic and tri-stereopair images were used to estimate the volumes of some lava flows and the main pyroclastic flow deposits. We estimated that the total volume of the magma that erupted during the 2014–2016 event was approximately 40 × 107 m3, which is one order of magnitude lower than that of the 1913 Plinian eruption. These data are fundamental for improving hazard assessment because the July 2015 eruption represents a unique scenario that has never before been observed at Volcán de Colima. Volume estimation provides complementary data to better understand eruptive processes, and detailed maps of the distributions of lava flows and pyroclastic flows represent fundamental tools for calibrating numerical modeling for hazard assessment. The stereo capabilities of the SPOT6/7 satellites for the detection of topographic changes and the and the availability of EO-1 ALI imagery are useful tools for reconstructing multitemporal eruptive events, even in areas that are not accessible due to ongoing eruptive activity.
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Xia, Wei, Jun Chen, Jianbo Liu, Caihong Ma und Wei Liu. „Landslide Extraction from High-Resolution Remote Sensing Imagery Using Fully Convolutional Spectral–Topographic Fusion Network“. Remote Sensing 13, Nr. 24 (16.12.2021): 5116. http://dx.doi.org/10.3390/rs13245116.
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Considering the complexity of landslide hazards, their manual investigation lacks efficiency and is time-consuming, especially in high-altitude plateau areas. Therefore, extracting landslide information using remote sensing technology has great advantages. In this study, comprehensive research was carried out on the landslide features of high-resolution remote sensing images on the Mangkam dataset. Based on the idea of feature-driven classification, the landslide extraction model of a fully convolutional spectral–topographic fusion network (FSTF-Net) based on a deep convolutional neural network of multi-source data fusion is proposed, which takes into account the topographic factor (slope and aspect) and the normalized difference vegetation index (NDVI) as multi-source data input by which to train the model. In this paper, a high-resolution remote sensing image classification method based on a fully convolutional network was used to extract the landslide information, thereby realizing the accurate extraction of the landslide and surrounding ground-object information. With Mangkam County in the southeast of the Qinghai–Tibet Plateau China as the study area, the proposed method was evaluated based on the high-precision digital elevation model (DEM) generated from stereoscopic images of Resources Satellite-3 and multi-source high-resolution remote sensing image data (Beijing-2, Worldview-3, and SuperView-1). Results show that our method had a landslide detection precision of 0.85 and an overall classification accuracy of 0.89. Compared with the latest DeepLab_v3+, our model increases the landslide detection precision by 5%. Thus, the proposed FSTF-Net model has high reliability and robustness.
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Gardner, A., G. Moholdt, A. Arendt und B. Wouters. „Accelerated contributions of Canada's Baffin and Bylot Island glaciers to sea level rise over the past half century“. Cryosphere 6, Nr. 5 (12.10.2012): 1103–25. http://dx.doi.org/10.5194/tc-6-1103-2012.
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Abstract. Canadian Arctic glaciers have recently contributed large volumes of meltwater to the world's oceans. To place recently observed glacier wastage into a historical perspective and to determine the region's longer-term (~50 years) contribution to sea level, we estimate mass and volume changes for the glaciers of Baffin and Bylot Islands using digital elevation models generated from airborne and satellite stereoscopic imagery and elevation postings from repeat airborne and satellite laser altimetry. In addition, we update existing glacier mass change records from GRACE satellite gravimetry to cover the period from 2003 to 2011. Using this integrated approach, we find that the rate of mass loss from the region's glaciers increased from 11.1 ± 3.4 Gt a−1 (271 ± 84 kg m−2 a−1) for the period 1963–2006 to 23.8 ± 6.1 Gt a−1 (581 ± 149 kg m−2 a−1) for the period 2003–2011. The doubling of the rate of mass loss is attributed to higher temperatures in summer with little change in annual precipitation. Through both direct and indirect effects, changes in summer temperatures accounted for 70–98% of the variance in the rate of mass loss, to which the Barnes Ice Cap was found to be 1.7 times more sensitive than either the Penny Ice Cap or the region's glaciers as a whole. This heightened sensitivity is the result of a glacier hypsometry that is skewed to lower elevations, which are shown to have a higher mass change sensitive to temperature compared to glacier surfaces at higher elevations. Between 2003 and 2011 the glaciers of Baffin and Bylot Islands contributed 0.07 ± 0.02 mm a−1 to sea level rise accounting for 16% of the total contribution from glaciers outside of Greenland and Antarctica, a rate much higher than the longer-term average of 0.03 ± 0.01 mm a−1 (1963 to 2006).
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Chénier, René, Marc-André Faucher, Ryan Ahola, Yask Shelat und Mesha Sagram. „Bathymetric Photogrammetry to Update CHS Charts: Comparing Conventional 3D Manual and Automatic Approaches“. ISPRS International Journal of Geo-Information 7, Nr. 10 (02.10.2018): 395. http://dx.doi.org/10.3390/ijgi7100395.
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The Canadian Hydrographic Service (CHS) supports safe navigation within Canadian waters through approximately 1000 navigational charts as well as hundreds of publications. One of the greatest challenges faced by the CHS is removing gaps in bathymetric survey data, particularly in the Canadian Arctic where only 6% of navigational water is surveyed to modern standards. Therefore, the CHS has initiated a research project to explore remote sensing methods to improve Canadian navigational charts. The major components of this project explore satellite derived bathymetry (SDB), coastline change detection and coastline extraction. This paper focuses on the potential of two stereo satellite techniques for deriving SDB: (i) automatic digital elevation model (DEM) extraction using a semi-global matching method, and (ii) 3D manual delineation of depth contours using visual stereoscopic interpretation. Analysis focused on quantitative assessment which compared estimated depths from both automatic and 3D manual photogrammetric approaches against available in situ survey depths. The results indicate that the 3D manual approach provides an accuracy of < 2 m up to a depth of 15 m. Comparable results were obtained from the automatic approach to a depth of 12 m. For almost all investigated depth ranges for both techniques, uncertainties were found to be within the required vertical accuracies for the International Hydrographic Organization category zone of confidence (CATZOC) level C classification for hydrographic surveys. This indicates that both techniques can be used to derive navigational quality bathymetric information within the investigated study site. While encouraging, neither technique was found to offer a single solution for the complete estimation of depth within the study area. As a result of these findings, the CHS envisions a hybrid approach where stereo- and reflectance-based bathymetry estimation techniques are implemented to provide the greatest understanding of depth possible from satellite imagery. Overall, stereo photogrammetry techniques will likely allow for new potential for supporting the improvement of CHS charts in areas where modern surveys have not yet been obtained.
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Kelly, Michael A., James L. Carr, Dong L. Wu, Arnold C. Goldberg, Ivan Papusha und Renee T. Meinhold. „Compact Midwave Imaging System: Results from an Airborne Demonstration“. Remote Sensing 14, Nr. 4 (10.02.2022): 834. http://dx.doi.org/10.3390/rs14040834.
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The Compact Midwave Imaging System (CMIS) is a wide field of view, multi-angle, multi-spectral pushframe imager that relies on the forward motion of the satellite to create a two-dimensional (2D) image swath. An airborne demonstration of CMIS was successfully completed in January–February 2021 on the NASA Langley Research Center Gulfstream III. The primary objective of the four-flight campaign was to demonstrate the capability of this unique instrument to perform stereo observations of clouds and other particulates (e.g., smoke) in the atmosphere. It is shown that the midwave infrared (MWIR) spectral bands of CMIS provide a unique 24/7 capability with high resolution for accurate stereo sensing. The instrument relies on new focal plane array (FPA) technology, which provides excellent sensitivity at much warmer detector temperatures than traditional technologies. This capability enabled a compact, low-cost design that can provide atmospheric motion vectors and cloud heights to support requirements for atmospheric winds in the 2017–2027 Earth Science Decadal Survey. Applications include day/night observations of the planetary boundary layer, severe weather, and wildfires. A comparison with current space-based earth science instruments demonstrates that the SWIR/MWIR multi-spectral capability of CMIS is competitive with larger, more expensive instrumentation. Imagery obtained over a controlled burn and operating nuclear power plant demonstrated the sensitivity of the instrument to temperature variations. The system relies on a mature stereoscopic imaging technique applied to the same scene from two independent platforms to unambiguously retrieve atmospheric motion vectors (AMVs) with accurate height assignment. This capability has been successfully applied to geostationary and low-earth orbit satellites to achieve excellent accuracy. When applied to a ground-point validation case, the accuracy for the CMIS aircraft observations was 20 m and 0.3 m/s for cloud heights and motion vectors, respectively. This result was confirmed by a detailed error analysis with analytical and covariance models. The results for CMIS cases with underflights of Aeolus, CALIPSO, and Aqua provided a good validation of expected accuracies. The paper also showed the feasibility of accommodating CMIS on CubeSats to enable multiple instruments to be flown in a leader–follower mode.
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G. Ferrigno, Jane, und Bruce F. Molnia. „Evaluation Of Landsat, Spot, and Sojuzkarta Data Of Antarctica For Ice and Climate Research“. Annals of Glaciology 14 (1990): 333–34. http://dx.doi.org/10.3189/s0260305500008946.
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Satellite data have proved suitable and cost-effective for ice and climate research in Antarctica. They have been used in numerous research efforts, including: monitoring coastal change, determining velocities of outlet glaciers, defining blue ice areas, tracking the movement of icebergs, and as a base for overlaying radar and other data. This paper reviews the data acquired since 1972 by the Landsat, SPOT and Sojuzkarta space systems and illustrates where good-quality (±10% cloud cover) data are available.The Landsat 1, 2, and 3 satellites acquired approximately 10 000 multispectral scanner (MSS) (80 m resolution) and return-beam vidicon (RBV) (30 m resolution) photographic and digital images of Antarctica between 1972 and 1983. The quality of these images has been evaluated by USGS to determine the feasibility of using them for glaciological, climatological, and geological research. Results have been plotted on a base map of Antarctica and show about 45% of the nominal scene centers, or about 70% of the geographic area of the continent, to be covered by good-quality imagery. Landsat 4 started acquiring data in 1982 and Landsat 5 in 1984. Together the two satellites acquired more than 4 500 thematic mapper (TM) (30 m resolution) and MSS images of Antarctica through the 1988–89 austral summer season, which may be the last season of Landsat 4 and 5 acquisition. The majority of the scenes have been acquired by two major projects: the West German Institut für Angewandte Geodäsie project to acquire data from the Ronne Ice Shelf area to the Greenwich meridian, and the USGS project to acquire data of coastal Antarctica and the inland boundary of the ice shelves, for use by the Scientific Committee on Antarctic Research (SCAR) community. Landsat 4 and 5 have different orbital parameters from Landsat 1, 2, and 3. As a result Landsat 4 and 5 imagery have different areal coverage. The data also have been archived differently. While the Landsat 1, 2, and 3 data exist in film format, many Landsat 4 and 5 TM images exist only as high-density digital tapes, and, as a result, the scenes cannot be examined and evaluated before purchase. Computer evaluation of the Landsat 4 and 5 data indicate that about 1350 or about 30% of the images have 10% cloud cover or less. However, it is difficult for automatic systems or those unfamiliar with the area to discriminate between clouds and snow. Based on a sampling of the data, it is more likely that 10–15%, or about 500 scenes, are of good quality. Those scenes which have been examined and evaluated as part of the SCAR cooperative acquisition project and are known to be of good quality are plotted and compared with the earlier Landsat data. The combined plot gives accurate and reliable information on the location of good quality Landsat 1–5 data of Antarctica.More than 7 000 Sojuzkarta scenes have been collected over Antarctica since 1976. The most useful data consist of photography from the KATE-200 system (20 m resolution) and the KFA-1000 system (6 m resolution). The data have been plotted by the U.S. Geological Survey and will soon be available as an open-file report. Those scenes which have been evaluated as having 10% cloud cover or less are plotted separately and overlaid on the Landsat plots. Scenes which have been examined are excellent, but an insufficient number of scenes have been inspected to evaluate the accuracy of the cloud cover estimation.The Systeme Probatoire d'Observation de la Terre (SPOT) was launched in 1986 and has acquired more than 1200 scenes of Antarctica. SPOT data consist of multi-spectral (20 m resolution) and panchromatic (10 m resolution) photographic or digital imagery. SPOT also possesses a mechanical plane mirror which permits off-nadir imaging and the generation of stereoscopic images. The locations of these scenes are now being plotted by the U.S. Geological Survey. Scenes with 10% cloud cover or less will be combined with Landsat and Sojuzkarta data to provide an accurate summary of the availability and coverage of high-quality satellite data of Antarctica.
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G. Ferrigno, Jane, und Bruce F. Molnia. „Evaluation Of Landsat, Spot, and Sojuzkarta Data Of Antarctica For Ice and Climate Research“. Annals of Glaciology 14 (1990): 333–34. http://dx.doi.org/10.1017/s0260305500008946.
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Satellite data have proved suitable and cost-effective for ice and climate research in Antarctica. They have been used in numerous research efforts, including: monitoring coastal change, determining velocities of outlet glaciers, defining blue ice areas, tracking the movement of icebergs, and as a base for overlaying radar and other data. This paper reviews the data acquired since 1972 by the Landsat, SPOT and Sojuzkarta space systems and illustrates where good-quality (±10% cloud cover) data are available. The Landsat 1, 2, and 3 satellites acquired approximately 10 000 multispectral scanner (MSS) (80 m resolution) and return-beam vidicon (RBV) (30 m resolution) photographic and digital images of Antarctica between 1972 and 1983. The quality of these images has been evaluated by USGS to determine the feasibility of using them for glaciological, climatological, and geological research. Results have been plotted on a base map of Antarctica and show about 45% of the nominal scene centers, or about 70% of the geographic area of the continent, to be covered by good-quality imagery. Landsat 4 started acquiring data in 1982 and Landsat 5 in 1984. Together the two satellites acquired more than 4 500 thematic mapper (TM) (30 m resolution) and MSS images of Antarctica through the 1988–89 austral summer season, which may be the last season of Landsat 4 and 5 acquisition. The majority of the scenes have been acquired by two major projects: the West German Institut für Angewandte Geodäsie project to acquire data from the Ronne Ice Shelf area to the Greenwich meridian, and the USGS project to acquire data of coastal Antarctica and the inland boundary of the ice shelves, for use by the Scientific Committee on Antarctic Research (SCAR) community. Landsat 4 and 5 have different orbital parameters from Landsat 1, 2, and 3. As a result Landsat 4 and 5 imagery have different areal coverage. The data also have been archived differently. While the Landsat 1, 2, and 3 data exist in film format, many Landsat 4 and 5 TM images exist only as high-density digital tapes, and, as a result, the scenes cannot be examined and evaluated before purchase. Computer evaluation of the Landsat 4 and 5 data indicate that about 1350 or about 30% of the images have 10% cloud cover or less. However, it is difficult for automatic systems or those unfamiliar with the area to discriminate between clouds and snow. Based on a sampling of the data, it is more likely that 10–15%, or about 500 scenes, are of good quality. Those scenes which have been examined and evaluated as part of the SCAR cooperative acquisition project and are known to be of good quality are plotted and compared with the earlier Landsat data. The combined plot gives accurate and reliable information on the location of good quality Landsat 1–5 data of Antarctica. More than 7 000 Sojuzkarta scenes have been collected over Antarctica since 1976. The most useful data consist of photography from the KATE-200 system (20 m resolution) and the KFA-1000 system (6 m resolution). The data have been plotted by the U.S. Geological Survey and will soon be available as an open-file report. Those scenes which have been evaluated as having 10% cloud cover or less are plotted separately and overlaid on the Landsat plots. Scenes which have been examined are excellent, but an insufficient number of scenes have been inspected to evaluate the accuracy of the cloud cover estimation. The Systeme Probatoire d'Observation de la Terre (SPOT) was launched in 1986 and has acquired more than 1200 scenes of Antarctica. SPOT data consist of multi-spectral (20 m resolution) and panchromatic (10 m resolution) photographic or digital imagery. SPOT also possesses a mechanical plane mirror which permits off-nadir imaging and the generation of stereoscopic images. The locations of these scenes are now being plotted by the U.S. Geological Survey. Scenes with 10% cloud cover or less will be combined with Landsat and Sojuzkarta data to provide an accurate summary of the availability and coverage of high-quality satellite data of Antarctica.
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Levchenko, V., I. Shulga, А. Romanyuk und L. Bezverkha. „USE OF REMOTE GEOINFORMATION TECHNOLOGIES FOR FOREST PATHOLOGY MONITORING IN THE ZHYTOMYR POLISSYA“. Innovative Solution in Modern Science 2, Nr. 38 (30.03.2020): 20. http://dx.doi.org/10.26886/2414-634x.2(38)2020.3.
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Topical issues of remote assessment of the forest pathological condition of forests are substantiated, in particular, it is emphasized that today this type of decryption is the least developed link in the section of forest decoding. This is due to the unstable manifestation and diagnosis on the materials of aeronautical surveys of signs of deciphering trees and plantations of varying degrees of attenuation and drying. Forest decoding of aerospace imagery materials today is the process of recognizing aerial objects depicted on aerospace images and establishing their quantitative and qualitative characteristics. The subject of the work is the fundamental aspects of forest decoding, which in turn can be visual (eye, analytical), measuring, automatic (machine), as well as complex-analytical or automated (interactive). For all types of visual decoding of the investigated forest objects, as a rule, characterize, on the basis of decryption signs, its image on an aerial photo or space picture (on paper or computer screen) with the naked eye or by means of magnifying or stereoscopic devices. Therefore, methodological correctness and clarity in deciphering satellite images of forest arrays obtained through satellite communication channels is quite important today, using satellite and internet technologies. The purpose of the study is to study and systematize materials for deciphering geoinformation images of forests that were obtained by satellite sounding of forests in Ukraine as a whole, and in the Zhytomyr region in particular. The main methods of carrying out the works are the computational-analytical on the collection and processing of the results of space images of satellite sounding of forests located in the territory of Zhytomyr region. In addition, it should be noted that remote satellite sensing of forests enables, with the correct methodological decryption of space images, not only to monitor, but also to make a prediction of the spread of harmful organisms in the forests of Zhytomyr region. The main methods of carrying out the works are the computational-analytical on the collection and processing of the results of space images of satellite sounding of forests located in the territory of Zhytomyr region. In addition, it should be noted that remote satellite sensing of forests enables, with the correct methodological decryption of space images, not only to monitor, but also to make a prediction of the spread of harmful organisms in the forests of Zhytomyr region. According to the results of the work, it is established that the information from the aerospace image is read and analyzed by means of visual and logical devices of the decoder. Therefore, analytical decryption, and especially with the use of certified computer software, allows not only a high-quality reading of space images of forest covered areas of Zhytomyr region, but also to make a long-term forecast for the spread and spread of pests and diseases of the forest in a certain area. The scope of the research results are forestry enterprises of the Zhytomyr Regional Forestry and Hunting Directorate, Ecological and Naturalistic Centers, State environmental inspections including in the Zhytomyr region for space monitoring of the state of forest ecosystems, as well as conducting forestry and nature activities forest of Zhytomyr Polesie. The conclusions of the research are that in Zhytomyr Polissya, when measuring decryption, all or some of the parameters and characteristics of the decrypted objects are measured in pictures using mechanical, opto-mechanical, opto-electronic and other measuring instruments, devices, devices and systems. In analytical-measuring decryption, a visual-logical analysis of the image is combined with the measurement of different parameters of the decrypted objects. Automatic decryption is based on the recognition of spectral and morphometric characteristics of decrypted objects, their quantitative and qualitative indicators. In this case, the decryption process is performed using image processing equipment. The role of the individual is to create a system, define a specific task and process the captured information with the help of appropriate programs, and to maintain the normal functioning of the system. Automated (interactive) decryption combines elements of analytic-measuring, performed by the decryptor-operator on the image on the computer screen, with automatic decryption. In this case, the collected information is analyzed and processed using technical means of image processing with the active participation of the decoder. Depending on the location, the decryption can be field, camera (laboratory), aerial or combined. Field decryption is carried out directly on the ground by comparing the image on aerial or space images with nature. The field decryption method is the simplest and most accurate, but it takes a lot of time and labor. Cameral decryption is carried out in the laboratory, while reducing the cost of engineering staff and workers, there is an acceleration of work and a significant reduction in their cost. Camera decryption is always done with the help of additional cartographic, regulatory and other stock materials. Aero-visual decryption is performed by comparing images of identified objects in aerial or space imagery with terrain when flying on planes or helicopters. The analysis of the informative content of the shooting materials shows that their practical application is possible, as a rule, on the basis of a rational combination of methods of terrestrial and remote observations.Keywords: remote evaluation, forest pathological condition, aerial photos, aerial photos, remote satellite sounding of forests, signs of decryption, space monitoring of forests in Zhytomyr region.
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Çöltekin, Arzu, Gianna Hartung und Martina Meyer. „Deconstructing the relief inversion effect: Contributors of the problem and its solutions“. Abstracts of the ICA 1 (15.07.2019): 1–2. http://dx.doi.org/10.5194/ica-abs-1-48-2019.
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<p><strong>Abstract.</strong> <i>Terrain reversal</i> (also known as <i>relief inversion</i>) effect is a common and well-known illusion encountered in shaded relief maps and satellite imagery where the main depth cue is shading/shadows (Imhof, 1967; Bernabe-Poveda, Callejo, & Ballari, 2005; Saraf, Das, Agarwal, & Sundaram, 1996; Biland & Çöltekin, 2016; Çöltekin, Rautenbach, Coetzee, & Mokwena, 2018). This illusion interferes with our perception of <i>shape from shading</i> (e.g., see Kleffner & Ramachandran, 1992; Prados & Faugeras, 2006). If the light shines from below, the shadows are then above, and this conflicts with the human mind’s ‘unconscious statistics’, that is, our minds assume that the light is more or less always above. This cognitive phenomenon is termed <i>light from above prior</i> (Kleffner & Ramachandran, 1992). When the prior is violated, we see three-dimensional (3D) shapes ambiguously, or inverted; such that a valley looks like a ridge in a terrain representation and vice versa (Bernabé-Poveda, Sánchez-Ortega, & Çöltekin, 2011; Bernabé-Poveda & Çöltekin, 2014). In a recent study, we demonstrated that adding texture and color as opposed to the shading alone (as in the shaded relief maps) affect 3D shape identification performance (Çöltekin & Biland, 2018). More precisely, when texture is present, success rates are higher in correctly identifying valleys and ridges, as well as other 3D spatial relationships. This is possibly a result of interpreting the spatial relationships between terrain features because people can recognize them more easily (e.g., a river is easier to identify on a photo than on a shaded relief map). Somewhat surprisingly, we also observed that people are better with 3D shape identification with grayscale images than with the color images; which we interpreted as the result of more pronounced contrast in grayscale images (Çöltekin & Biland, 2018). Because we see that presence of other visual cues do interfere with the relief inversion effect, in this study, we explore other additional factors (depth cues, labels, terrain types, task types, expertise levels and spatial abilities) that may contribute to, or alleviate, the relief inversion effect. Understanding how other factors contribute to the strength of the illusion can help develop better-informed use of the displays that contain this illusion and lead to better solutions. In this vein, in a series of experiments, we examined effects of stereoscopic viewing vs. monoscopic viewing, terrain types (highly rugged vs. subtly rugged), task types (3D shape identification vs. land cover identification; simple vs. complex), expertise levels, and spatial abilities. In a second experiment, we examined how well various solutions function for correcting the illusion in various combinations of variables (labels, motion, stereo). Figure 1 shows an example of the shape identification tasks used in the first study.</p><p>We are developing full papers reporting the effects of each tested factor in detail, which would be beyond the scope of this short paper. In this short paper, we focus on the effects of stereo on the strength of the relief inversion experience (does showing the terrain in stereo make the relief inversion effect stronger or weaker?), and on the solutions for satellite images (if we combine a ‘solution’ with stereo viewing, do shape perception and land cover identification success improve?). The second question, especially the mention of land cover identification, is related to the fact that a common solution to terrain reversal effect is to overlay a semi-transparent shaded relief map (SRM overlay) on top of the image that has the perceptual problem (Bernabé-Poveda, Sánchez-Ortega, & Çöltekin, 2011; Saraf, Das, Agarwal, & Sundaram, 1996b).</p><p> Our initial findings suggest that stereo viewing does help against the issues in 3D shape perception; although it does not entirely remove it: 3D shape perception accuracy is &sim;15% with original images, &sim;32% with the stereo. When stereoscopic viewing is combined with an SRM overlay solution, it improves the 3D shape perception: 3D shape perception accuracy with the SRM overlay solution alone is &sim;40%, with added stereo &sim;68%, but impairs the land cover identification (accuracy is &sim;78% with the SRM overlay, and drops to &sim;44% when stereo is added). These findings are based on two controlled experiments with 33 and 35 participants respectively, and the differences are statistically significant based on analysis of variance (<i>p</i>&thinsp;&lt;&thinsp;0.05). We believe the impairment of the land cover identification is linked to the stereoscopic viewing method, as the tests were conducted with anaglyph stereo, where color perception is strongly affected. These observations, taken together, provide us the initial clues that providing the viewers with an additional depth cue (in this case stereopsis) is indeed helpful; but also suggest that the success of the solution depends on how it is implemented, and the nature of the task; for example, if color is important for the task or not.</p><p> We believe our findings are of key importance in understanding the relief inversion effect, and its future solutions, and will guide cartographers towards a more nuanced comprehension and work practices.</p></p>
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Seiz, G., E. P. Baltsavias und A. Gruen. „3D cloud products for weather prediction and climate modelling“. Geographica Helvetica 58, Nr. 2 (30.06.2003): 90–98. http://dx.doi.org/10.5194/gh-58-90-2003.
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Abstract. In this paper, the possibilities of satellite-based and ground-based stereoscopy of clouds are examined, with the objective to derive cloud top and cloud base heights and motion. These parameters are very important for a better description of clouds for nowcasting and numerical weather prediction models. For the satellite part, images of ATSR2 (on ERS-2) and MISR (on EOS Terra) are used. As stereo image pairs from polar-orbiting satellites are never perfectly synchronous (time delay of some seconds between the image reeeption from the different viewing angles), the height error of the cloud top heights, introduced by the along-track motion component, is corrected with the cloud top winds extracted from Meteosat-6 and -7. For MISR, with nine viewing angles, this height correction is not needed when at least three images from non-symmetric cameras are used; then, it is possible to directly separate the along-track parallax (due to cloud height) from the along-track wind contribution (due to cloud motion). Our new ground-based imager System was operated in eoineidence with an overpass of ERS-2 in October 1999. The ground measurements proved to be an interesting technique to validate satellite-based cloud top height and motion of vertically thin clouds and to additionally detect more detailed cloud features, which is particularly important for aecurate noweasting in mountainous terrain.
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Carr, James L., Dong L. Wu, Robert E. Wolfe, Houria Madani, Guoqing (Gary) Lin und Bin Tan. „Joint 3D-Wind Retrievals with Stereoscopic Views from MODIS and GOES“. Remote Sensing 11, Nr. 18 (09.09.2019): 2100. http://dx.doi.org/10.3390/rs11182100.
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Atmospheric motion vectors (AMVs), derived by tracking patterns, represent the winds in a layer characteristic of the pattern. AMV height (or pressure), important for applications in atmospheric research and operational meteorology, is usually assigned using observed IR brightness temperatures with a modeled atmosphere and can be inaccurate. Stereoscopic tracking provides a direct geometric height measurement of the pattern that an AMV represents. We extend our previous work with multi-angle imaging spectro–radiometer (MISR) and GOES to moderate resolution imaging spectroradiometer (MODIS) and the GOES-R series advanced baseline imager (ABI). MISR is a unique satellite instrument for stereoscopy with nine angular views along track, but its images have a narrow (380 km) swath and no thermal IR channels. MODIS provides a much wider (2330 km) swath and eight thermal IR channels that pair well with all but two ABI channels, offering a rich set of potential applications. Given the similarities between MODIS and VIIRS, our methods should also yield similar performance with VIIRS. Our methods, as enabled by advanced sensors like MODIS and ABI, require high-accuracy geographic registration in both systems but no synchronization of observations. AMVs are retrieved jointly with their heights from the disparities between triplets of ABI scenes and the paired MODIS granule. We validate our retrievals against MISR-GOES retrievals, operational GOES wind products, and by tracking clear-sky terrain. We demonstrate that the 3D-wind algorithm can produce high-quality AMV and height measurements for applications from the planetary boundary layer (PBL) to the upper troposphere, including cold-air outbreaks, wildfire smoke plumes, and hurricanes.
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Wang, Hao, Xiaolei Lv, Kaiyu Zhang und Bin Guo. „Building Change Detection Based on 3D Co-Segmentation Using Satellite Stereo Imagery“. Remote Sensing 14, Nr. 3 (28.01.2022): 628. http://dx.doi.org/10.3390/rs14030628.
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Building change detection using remote sensing images is significant to urban planning and city monitoring. The height information extracted from very high resolution (VHR) satellite stereo images provides valuable information for the detection of 3D changes in urban buildings. However, most existing 3D change detection algorithms are based on the independent segmentation of two-temporal images and the feature fusion of spectral change and height change. These methods do not consider 3D change information and spatial context information simultaneously. In this paper, we propose a novel building change detection algorithm based on 3D Co-segmentation, which makes full use of the 3D change information contained in the stereoscope data. An energy function containing spectral change information, height change information, and spatial context information is constructed. Image change feature is extracted using morphological building index (MBI), and height change feature is obtained by robust normalized digital surface models (nDSM) difference. 3D Co-segmentation divides the two-temporal images into the changed foreground and unchanged background through the graph-cut-based energy minimization method. The object-to-object detection results are obtained through overlay analysis, and the quantitative height change values are calculated according to this correspondence. The superiority of the proposed algorithm is that it can obtain the changes of buildings in planar and vertical simultaneously. The performance of the algorithm is evaluated in detail using six groups of satellite datasets. The experimental results prove the effectiveness of the proposed building change detection algorithm.
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Zhong, Liang, Xueyuan Chu, Jiawei Qian, Jianlong Li und Zhengguo Sun. „Multi-Scale Stereoscopic Hyperspectral Remote Sensing Estimation of Heavy Metal Contamination in Wheat Soil over a Large Area of Farmland“. Agronomy 13, Nr. 9 (16.09.2023): 2396. http://dx.doi.org/10.3390/agronomy13092396.
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With the rapid development of China’s industrialization and urbanization, the problem of heavy metal pollution in soil has become increasingly prominent, seriously threatening the safety of the ecosystem and human health. The development of hyperspectral remote sensing technology provides the possibility to achieve the rapid and non-destructive monitoring of soil heavy metal contents. This study aimed to fully explore the potential of ground and satellite image spectra in estimating soil heavy metal contents. We chose Xushe Town, Yixing City, Jiangsu Province as the research area, collected soil samples from farmland over two different periods, and measured the contents of the heavy metals Cd and As in the laboratory. At the same time, under field conditions, we also measured the spectra of wheat leaves and obtained HuanJing-1A HyperSpectral Imager (HJ-1A HSI) satellite image data. We first performed various spectral transformation pre-processing techniques on the leaf and image spectral data. Then, we used genetic algorithm (GA) optimized partial least squares regression (PLSR) to establish an estimation model of the soil heavy metal Cd and As contents, while evaluating the accuracy of the model. Finally, we obtained the best ground and satellite remote sensing estimation models and drew spatial distribution maps of the soil Cd and As contents in the study area. The results showed the following: (1) spectral pre-processing techniques can highlight some hidden information in the spectra, including mathematical transformations such as differentiation; (2) in ground and satellite spectral modeling, the GA-PLSR model has higher accuracy than PLSR, and using a GA for spectral band selection can improve the model’s accuracy and stability; (3) wheat leaf spectra provide a good ability to estimate soil Cd (relative percent difference (RPD) = 2.72) and excellent ability to estimate soil As (RPD = 3.25); HJ-1A HSI image spectra only provide the possibility of distinguishing high and low values of soil Cd and As (RPD = 1.87, RPD = 1.91). Therefore, it is possible to indirectly estimate soil heavy metal Cd and As contents using wheat leaf hyperspectral data, and HJ-1A HSI image spectra can also identify areas of key pollution.
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Kestilä, A., T. Tikka, P. Peitso, J. Rantanen, A. Näsilä, K. Nordling, H. Saari et al. „Aalto-1 nanosatellite – technical description and mission objectives“. Geoscientific Instrumentation, Methods and Data Systems Discussions 2, Nr. 2 (26.11.2012): 925–51. http://dx.doi.org/10.5194/gid-2-925-2012.
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Abstract. This work presents the outline and so far completed design of the Aalto-1 science mission. Aalto-1 is a multi-payload remote sensing nanosatellite, built almost entirely by students. The satellite aims for a 500–900 km sun-synchronous orbit, and includes an accurate attitude dynamics and control unit, a UHF/VHF housekeeping and S-band data links, and a GPS unit for positioning (radio positioning and NORAD TLE's are planned to be used as backups). It has three specific payloads: a spectral imager based on piezo-actuated Fabry–Perot interferometry, designed and built by The Technical Research Center of Finland (VTT); a miniaturized radiation monitor (RADMON) jointly designed and built by Universities of Helsinki and Turku ; and an electrostatic plasma brake designed and built by the Finnish Meteorological Institute (FMI), derived from the concept of the e-sail, also originating from FMI. Two phases are important for the payloads, the technology demonstration and the science phase. Emphasis is placed on technological demonstration of the spectral imager and RADMON, and suitable targets have already been chosen to be completed during that phase, while the plasma brake will start operation in the latter part of the science phase. The technology demonstration will be over in relatively short time, while the science phase is planned to last two years. The science phase is divided into two smaller phases: the science observations phase, during which only the spectral imager and RADMON will be operated for 6–12 months, and the plasma brake demonstration phase, which is dedicated to the plasma brake experiment for at least a year. These smaller phases are necessary due to the drastically different power, communication and attitude requirements of the payloads. The spectral imager will be by far the most demanding instrument on board, as it requires most of the downlink bandwidth, has a high peak power and attitude performance. It will acquire images in a series up to at least 20 spectral bands within the 500–900 nm spectral range, forming the desired spectral data cube product. Shortly before an image is acquired, the parallel visual spectrum camera will take a broader picture for comparison. Also stereoscopic imaging is planned. The amount of data collected by the spectral imager is adjustable, and ranges anywhere from 10 to 500 MB. The RADMON will be on 80% of an orbit period in average and together with housekeeping data will gather around 2 MB of data in 24 h. An operational limitation is formed due to the S-band downlink capability of 29–49 MB per 24 h for a 500 900 km orbit altitude, as only one ground station is planned to be available to the satellite. This will limit both type and quantity of spectral imager images taken during the science phase. The plasma brake will in turn be on within an angle of 20° over the poles for efficient use of the Earth's magnetic field and ionosphere during its spin-up and operation.
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Kestilä, A., T. Tikka, P. Peitso, J. Rantanen, A. Näsilä, K. Nordling, H. Saari et al. „Aalto-1 nanosatellite – technical description and mission objectives“. Geoscientific Instrumentation, Methods and Data Systems 2, Nr. 1 (21.02.2013): 121–30. http://dx.doi.org/10.5194/gi-2-121-2013.
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Abstract. This work presents the outline and so far completed design of the Aalto-1 science mission. Aalto-1 is a multi-payload remote-sensing nanosatellite, built almost entirely by students. The satellite aims for a 500–900 km sun-synchronous orbit and includes an accurate attitude dynamics and control unit, a UHF/VHF housekeeping and S-band data links, and a GPS unit for positioning (radio positioning and NORAD TLE's are planned to be used as backup). It has three specific payloads: a spectral imager based on piezo-actuated Fabry–Perot interferometry, designed and built by The Technical Research Centre of Finland (VTT); a miniaturised radiation monitor (RADMON) jointly designed and built by Universities of Helsinki and Turku; and an electrostatic plasma brake designed and built by the Finnish Meteorological Institute (FMI), derived from the concept of the e-sail, also originating from FMI. Two phases are important for the payloads, the technology demonstration and the science phase. The emphasis is placed on technological demonstration of the spectral imager and RADMON, and suitable targets have already been chosen to be completed during that phase, while the plasma brake will start operation in the latter part of the science phase. The technology demonstration will be over in a relatively short time, while the science phase is planned to last two years. The science phase is divided into two smaller phases: the science observations phase, during which only the spectral imager and RADMON will be operated for 6–12 months and the plasma brake demonstration phase, which is dedicated to the plasma brake experiment for at least a year. These smaller phases are necessary due to the drastically different power, communication and attitude requirements of the payloads. The spectral imager will be by far the most demanding instrument on board, as it requires most of the downlink bandwidth, has a high peak power and attitude performance. It will acquire images in a series up to at least 20 spectral bands within the 500–900 nm spectral range, forming the desired spectral data cube product. Shortly before an image is acquired, the parallel visual spectrum camera will take a broader picture for comparison. Also stereoscopic imaging is planned. The amount of data collected by the spectral imager is adjustable, and ranges anywhere from 10 to 500 MB. The RADMON will be on 80% of an orbit period on average and together with housekeeping data will gather around 2 MB of data in 24 h. An operational limitation is formed due to the S-band downlink capability of 29–49 MB per 24 h for a 500 900 km orbit altitude, as only one ground station is planned to be available for the satellite. This will limit both type and quantity of spectral imager images taken during the science phase. The plasma brake will in turn be within an angle of 20° over the poles for efficient use of the Earth's magnetic field and ionosphere during its spin-up and operation.
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Prata, Fred, und Mervyn Lynch. „Passive Earth Observations of Volcanic Clouds in the Atmosphere“. Atmosphere 10, Nr. 4 (12.04.2019): 199. http://dx.doi.org/10.3390/atmos10040199.
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Current Earth Observation (EO) satellites provide excellent spatial, temporal and spectral coverage for passive measurements of atmospheric volcanic emissions. Of particular value for ash detection and quantification are the geostationary satellites that now carry multispectral imagers. These instruments have multiple spectral channels spanning the visible to infrared (IR) wavelengths and provide 1 × 1 km2 to 4 × 4 km2 resolution data every 5–15 min, continuously. For ash detection, two channels situated near 11 and 12 μ m are needed; for ash quantification a third or fourth channel also in the infrared is useful for constraining the height of the ash cloud. This work describes passive EO infrared measurements and techniques to determine volcanic cloud properties and includes examples using current methods with an emphasis on the main difficulties and ways to overcome them. A challenging aspect of using satellite data is to design algorithms that make use of the spectral, temporal (especially for geostationary sensors) and spatial information. The hyperspectral sensor AIRS is used to identify specific molecules from their spectral signatures (e.g., for SO2) and retrievals are demonstrated as global, regional and hemispheric maps of AIRS column SO2. This kind of information is not available on all sensors, but by combining temporal, spatial and broadband multi-spectral information from polar and geo sensors (e.g., MODIS and SEVIRI) useful insights can be made. For example, repeat coverage of a particular area using geostationary data can reveal temporal behaviour of broadband channels indicative of eruptive activity. In many instances, identifying the nature of a pixel (clear, cloud, ash etc.) is the major challenge. Sophisticated cloud detection schemes have been developed that utilise statistical measures, physical models and temporal variation to classify pixels. The state of the art on cloud detection is good, but improvements are always needed. An IR-based multispectral cloud identification scheme is described and some examples shown. The scheme is physically based but has deficiencies that can be improved during the daytime by including information from the visible channels. Physical retrieval schemes applied to ash detected pixels suffer from a lack of knowledge of some basic microphysical and optical parameters needed to run the retrieval models. In particular, there is a lack of accurate spectral refractive index information for ash particles. The size distribution of fine ash (1–63 μ m, diameter) is poorly constrained and more measurements are needed, particularly for ash that is airborne. Height measurements are also lacking and a satellite-based stereoscopic height retrieval is used to illustrate the value of this information for aviation. The importance of water in volcanic clouds is discussed here and the separation of ice-rich and ash-rich portions of volcanic clouds is analysed for the first time. More work is required in trying to identify ice-coated ash particles, and it is suggested that a class of ice-rich volcanic cloud be recognized and termed a ‘volcanic ice’ cloud. Such clouds are frequently observed in tropical eruptions of great vertical extent (e.g., 8 km or higher) and are often not identified correctly by traditional IR methods (e.g., reverse absorption). Finally, the global, hemispheric and regional sampling of EO satellites is demonstrated for a few eruptions where the ash and SO 2 dispersed over large distances (1000s km).
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KING, R. BRUCE. „The value of ground resolution, spectral range and stereoscopy of satellite imagery for land system and land-use mapping of the humid tropics“. International Journal of Remote Sensing 15, Nr. 3 (Februar 1994): 521–30. http://dx.doi.org/10.1080/01431169408954093.
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Deschamps‐Berger, C., B. Cluzet, M. Dumont, M. Lafaysse, E. Berthier, P. Fanise und S. Gascoin. „Improving the Spatial Distribution of Snow Cover Simulations by Assimilation of Satellite Stereoscopic Imagery“. Water Resources Research 58, Nr. 3 (März 2022). http://dx.doi.org/10.1029/2021wr030271.
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Bramorska, Beata. „Open Forest Data: Digitalizing and building an online repository“. Biodiversity Information Science and Standards 5 (27.09.2021). http://dx.doi.org/10.3897/biss.5.75783.
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Poland is characterised by a relatively high variety of living organisms attributed to terrestrial and water environments. Currently, close to 57.000 species of living organisms are described that occur in Poland (Symonides 2008), including lowland and mountain species, those attributed to oceanic and continental areas, as well as species from forested and open habitats. Poland comprehensively represents biodiversity of living organisms on a continental scale and thus, is considered to have an important role for biodiversity maintenance. The Mammal Research Institute of Polish Academy of Sciences (MRI PAS), located in Białowieża Forest, a UNESCO Heritage Site, has been collecting biodiversity data for 90 years. However, a great amount of data gathered over the years, especially old data, is gradually being forgotten and hard to access. Old catalogues and databases have never been digitalized or publicly shared, and not many Polish scientists are aware of the existence of such resources, not to mention the rest of the scientific world. Recognizing the need for an online, interoperable platform, following FAIR data principles (findable, accessible, interoperable, reusable), where biodiversity and scientific data can be shared, MRI PAS took a lead in creation of an Open Forest Data (OFD) repository. OpenForestData.pl (Fig. 1) is a newly created (2020) digital repository, designed to provide access to natural sciences data and provide scientists with an infrastructure for storing, sharing and archiving their research outcomes. Creating such a platform is a part of an ongoing development of life sciences in Poland, aiming for an open, modern science, where data are published as free-access. OFD also allows for the consolidation of natural science data, enabling the use and processing of shared data, including API (Application Programming Interface) tools. OFD is indexed by the Directory of Open Repositories (OpenDOAR) and Registry of Research Data Repositories (re3data). The OFD platform is based entirely on reliable, globally recognized open source software: DATAVERSE, an interactive database app which supports sharing, storing, exploration, citation and analysis of scientific data; GEONODE, a content management geospatial system used for storing, publicly sharing and visualising vector and raster layers, GRAFANA, a system meant for storing and analysis of metrics and large scale measurement data, as well as visualisation of historical graphs at any time range and analysis for trends; and external tools for database storage (Orthanc) and data visualisation (Orthanc plugin Osimis Web Viewer and Online 3D Viewer (https://3dviewer.net/), which were integrated with the system mechanism of Dataverse. Furthermore, according to the need for specimen description, Darwin Core (Wieczorek et al. 2012) metadata schema was decided to be the most suitable for specimen and collections description and mapped into a Dataverse additional metadata block. The use of Darwin Core is based on the same file format, the Darwin Core Archive (DwC-A) which allows for sharing data using common terminology and provides the possibility for easy evaluation and comparison of biodiversity datasets. It allows the contributors to OFD to optionally choose Darwin Core for object descriptions making it possible to share biodiversity datasets in a standardized way for users to download, analyse and compare. Currently, OFD stores more than 10.000 datasets and objects from the collections of Mammal Research Institute of Polish Academy of Sciences and Forest Science Institute of Białystok University of Technology. The objects from natural collections were digitalized, described, catalogued and made public in free-access. OFD manages seven types of collection materials: 3D and 2D scans of specimen in Herbarium, Fungarium, Insect and Mammal Collections, images from microscopes (including stereoscopic and scanning electron microscopes), morphometric measurements, computed tomography and microtomography scans in Mammal Collection, mammal telemetry data, satellite imagery, geospatial climatic and environmental data, georeferenced historical maps. 3D and 2D scans of specimen in Herbarium, Fungarium, Insect and Mammal Collections, images from microscopes (including stereoscopic and scanning electron microscopes), morphometric measurements, computed tomography and microtomography scans in Mammal Collection, mammal telemetry data, satellite imagery, geospatial climatic and environmental data, georeferenced historical maps. In the OFD repository, researchers have the possibility to share data in standardized way, which nowadays is often a requirement during the publishing process of a scientific article. Beside scientists, OFD is designed to be open and free for students and specialists in nature protection, but also for officials, foresters and nature enthusiasts. Creation of the OFD repository supports the development of citizen science in Poland, increases visibility and access to published data, improves scientific collaboration, exchange and reuse of data within and across borders.
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Apke, Jason M., und John R. Mecikalski. „On the Origin of Rotation Derived from Super Rapid Scan Satellite Imagery at the Cloud-Tops of Severe Deep Convection“. Monthly Weather Review, 30.03.2021. http://dx.doi.org/10.1175/mwr-d-20-0209.1.
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AbstractSevere thunderstorms routinely exhibit adjacent maxima and minima in cloud-top vertical vorticity (CTV) downstream of overshooting tops within flow fields retrieved using sequences of fine-temporal resolution (1-min) geostationary operational environmental satellite (GOES)-R series imagery. Little is known about the origin of this so-called “CTV couplet” signature, and whether the signature is the result of flow field derivational artifacts. Thus, the CTV signature’s relevance to research and operations is currently ambiguous. Within this study, we explore the origin of near-cloud-top rotation using an idealized supercell numerical model simulation. Employing an advanced dense optical flow algorithm, image stereoscopy, and numerical model background wind approximations, the artifacts common with cloud-top flow field derivation are removed from two supercell case studies sampled by GOES-R imagers. It is demonstrated that the CTV couplet originates from tilted and converged horizontal vorticity that is baroclinically generated in the upper levels (above 10 km) immediately downstream of the overshooting top. This baroclinic generation would not be possible without a strong and sustained updraft, implying an indirect relationship to rotationally-maintained supercells. Furthermore, it is demonstrated that CTV couplets derived with optical flow algorithms originate from actual rotation within the storm anvils in the case studies explored here, though supercells with opaque above anvil cirrus plumes and strong anvil-level negative vertical wind shear may produce rotation signals as an artifact without quality control. Artifact identification and quality control is discussed further here for future research and operations use.