scholarly journals Assessment of Spatio-Temporal Landscape Changes from VHR Images in Three Different Permafrost Areas in the Western Russian Arctic

2020 ◽  
Vol 12 (23) ◽  
pp. 3999
Author(s):  
Florina Ardelean ◽  
Alexandru Onaca ◽  
Marinela-Adriana Chețan ◽  
Andrei Dornik ◽  
Goran Georgievski ◽  
...  
Keyword(s):  
High Resolution ◽  
Snow Water Equivalent ◽  
Water Bodies ◽  
Yamal Peninsula ◽  
River Channels ◽  
Pronounced Increase ◽  
Discontinuous Permafrost ◽  
Spatio Temporal ◽  
Very High ◽  
The Yamal Peninsula

Our study highlights the usefulness of very high resolution (VHR) images to detect various types of disturbances over permafrost areas using three example regions in different permafrost zones. The study focuses on detecting subtle changes in land cover classes, thermokarst water bodies, river dynamics, retrogressive thaw slumps (RTS) and infrastructure in the Yamal Peninsula, Urengoy and Pechora regions. Very high-resolution optical imagery (sub-meter) derived from WorldView, QuickBird and GeoEye in conjunction with declassified Corona images were involved in the analyses. The comparison of very high-resolution images acquired in 2003/2004 and 2016/2017 indicates a pronounced increase in the extent of tundra and a slight increase of land covered by water. The number of water bodies increased in all three regions, especially in discontinuous permafrost, where 14.86% of new lakes and ponds were initiated between 2003 and 2017. The analysis of the evolution of two river channels in Yamal and Urengoy indicates the dominance of erosion during the last two decades. An increase of both rivers’ lengths and a significant widening of the river channels were also observed. The number and total surface of RTS in the Yamal Peninsula strongly increased between 2004 and 2016. A mean annual headwall retreat rate of 1.86 m/year was calculated. Extensive networks of infrastructure occurred in the Yamal Peninsula in the last two decades, stimulating the initiation of new thermokarst features. The significant warming and seasonal variations of the hydrologic cycle, in particular, increased snow water equivalent acted in favor of deepening of the active layer; thus, an increasing number of thermokarst lake formations.

scholarly journals SMC-Flood database: a high-resolution press database on flood cases for the Spanish Mediterranean coast (1960–2015)

2019 ◽  
Vol 19 (9) ◽  
pp. 1955-1971 ◽  
Author(s):  
Salvador Gil-Guirado ◽  
Alfredo Pérez-Morales ◽  
Francisco Lopez-Martinez
Keyword(s):  
High Resolution ◽  
Spatial Planning ◽  
Latitudinal Gradient ◽  
Temporal Analysis ◽  
Mediterranean Coast ◽  
Digital Archives ◽  
Positive Aspect ◽  
Flood Database ◽  
Spatio Temporal ◽  
Very High

Abstract. Flood databases of high spatio-temporal resolution are a necessary tool for proper spatial planning, especially in areas with high levels of exposure and danger to floods. This study presents the preliminary results of the Spanish Mediterranean Coastal Flood (SMC-Flood) database covering the municipalities in this region. This database collects information on flood cases that occurred between 1960 and 2015 by systematically consulting the digital archives of the main newspapers in the study area. The search for flood information was conducted by means of using links between municipality names and seven keywords that correspond to the most common ways of referring to a situation that is likely to describe a flood in Spain. This methodology has enabled the reconstruction of 3008 flood cases at a municipal scale with daily resolution while gathering information on the types of damage, intensity, severity and area affected. The spatio-temporal analysis of the data reveals hotspots where flood cases are especially intense and damaging when compared to highly developed areas where the frequency of flood cases is very high. This situation is especially worrying insofar as we have detected a growing trend in the frequency and area affected by flood cases. However, one positive aspect is that the intensity and severity of flood cases follows a falling trend. The main novelty lies in the fact that the high-resolution spatial analysis has made it possible to detect a clear latitudinal gradient of growing intensity and severity in a north–south direction. This pattern calls for new actions by the coastal municipal authorities of southern Spain for adaptation to a more complex flood scenario.

scholarly journals Rich CNN Features for Water-Body Segmentation from Very High Resolution Aerial and Satellite Imagery

2021 ◽  
Vol 13 (10) ◽  
pp. 1912
Author(s):  
Zhili Zhang ◽  
Meng Lu ◽  
Shunping Ji ◽  
Huafen Yu ◽  
Chenhui Nie
Keyword(s):  
Remote Sensing ◽  
Feature Extraction ◽  
High Resolution ◽  
Satellite Imagery ◽  
Water Body ◽  
Feature Fusion ◽  
Feature Representation ◽  
Water Bodies ◽  
Feature Maps ◽  
Very High

Extracting water-bodies accurately is a great challenge from very high resolution (VHR) remote sensing imagery. The boundaries of a water body are commonly hard to identify due to the complex spectral mixtures caused by aquatic vegetation, distinct lake/river colors, silts near the bank, shadows from the surrounding tall plants, and so on. The diversity and semantic information of features need to be increased for a better extraction of water-bodies from VHR remote sensing images. In this paper, we address these problems by designing a novel multi-feature extraction and combination module. This module consists of three feature extraction sub-modules based on spatial and channel correlations in feature maps at each scale, which extract the complete target information from the local space, larger space, and between-channel relationship to achieve a rich feature representation. Simultaneously, to better predict the fine contours of water-bodies, we adopt a multi-scale prediction fusion module. Besides, to solve the semantic inconsistency of feature fusion between the encoding stage and the decoding stage, we apply an encoder-decoder semantic feature fusion module to promote fusion effects. We carry out extensive experiments in VHR aerial and satellite imagery respectively. The result shows that our method achieves state-of-the-art segmentation performance, surpassing the classic and recent methods. Moreover, our proposed method is robust in challenging water-body extraction scenarios.

scholarly journals New Method for Automated Quantification of Vertical Spatio-Temporal Changes within Gully Cross-Sections Based on Very-High-Resolution Models

2021 ◽  
Vol 13 (2) ◽  
pp. 321
Author(s):  
Ante Šiljeg ◽  
Fran Domazetović ◽  
Ivan Marić ◽  
Nina Lončar ◽  
Lovre Panđa
Keyword(s):  
High Resolution ◽  
Cross Sections ◽  
Research Question ◽  
Cost Effective ◽  
Practical Method ◽  
Temporal Changes ◽  
Field Methods ◽  
Main Research ◽  
Spatio Temporal ◽  
Very High

Gully erosion is one of the most prominent natural denudation processes of the Mediterranean. It causes significant soil degradation and sediment yield. Most traditional field methods for measurement of erosion-induced spatio-temporal changes are time and labor consuming, while their accuracy and precision are highly influenced by various factors. The main research question of this study was how the measurement approach of traditional field sampling methods can be automated and upgraded, while satisfying the required measurement accuracy. The VERTICAL method was developed as a fully automated raster-based method for detection and quantification of vertical spatio-temporal changes within a large number of gully cross-sections (GCs). The developed method was tested on the example of gully Santiš, located at Pag Island, Croatia. Repeat unmanned aerial vehicle (UAV) photogrammetry was used, as a cost-effective and practical method for the creation of very-high-resolution (VHR) digital surface models (DSMs) of the chosen gully site. A repeat aerophotogrammetric system (RAPS) was successfully assembled and integrated into one functional operating system. RAPS was successfully applied for derivation of interval (the two-year research period) DSMs (1.9 cm/pix) of gully Santiš with the accuracy of ±5 cm. VERTICAL generated and measured 2379 GCs, along the 110 m long thalweg of gully Santiš, within which 749 052 height points were sampled in total. VERTICAL proved to be a fast and reliable method for automated detection and calculation of spatio-temporal changes in a large number of GCs, which solved some significant shortcomings of traditional field methods. The versatility and adaptability of VERTICAL allow its application for other, similar scientific purposes, where multitemporal accurate measurement of spatio-temporal changes in GCs is required (e.g., river material dynamics, ice mass dynamics, tufa sedimentation and erosion).

scholarly journals Monitoring the Transformation of Arctic Landscapes: Automated Shoreline Change Detection of Lakes Using Very High Resolution Imagery

2021 ◽  
Vol 13 (14) ◽  
pp. 2802
Author(s):  
Soraya Kaiser ◽  
Guido Grosse ◽  
Julia Boike ◽  
Moritz Langer
Keyword(s):  
High Resolution ◽  
Shoreline Change ◽  
Weather Conditions ◽  
Water Bodies ◽  
Additional Information ◽  
High Resolution Imagery ◽  
High Resolution Satellite Images ◽  
High Resolution Satellite Imagery ◽  
Image Metadata ◽  
Very High

Water bodies are a highly abundant feature of Arctic permafrost ecosystems and strongly influence their hydrology, ecology and biogeochemical cycling. While very high resolution satellite images enable detailed mapping of these water bodies, the increasing availability and abundance of this imagery calls for fast, reliable and automatized monitoring. This technical work presents a largely automated and scalable workflow that removes image noise, detects water bodies, removes potential misclassifications from infrastructural features, derives lake shoreline geometries and retrieves their movement rate and direction on the basis of ortho-ready very high resolution satellite imagery from Arctic permafrost lowlands. We applied this workflow to typical Arctic lake areas on the Alaska North Slope and achieved a successful and fast detection of water bodies. We derived representative values for shoreline movement rates ranging from 0.40–0.56 m.yr−1 for lake sizes of 0.10 ha–23.04 ha. The approach also gives an insight into seasonal water level changes. Based on an extensive quantification of error sources, we discuss how the results of the automated workflow can be further enhanced by incorporating additional information on weather conditions and image metadata and by improving the input database. The workflow is suitable for the seasonal to annual monitoring of lake changes on a sub-meter scale in the study areas in northern Alaska and can readily be scaled for application across larger regions within certain accuracy limitations.

scholarly journals Ecological state of water bodies and their water protection zones within the boundaries of settlements of the Yamal Peninsula

2021 ◽  
Vol 265 ◽  
pp. 02009
Author(s):  
Roman Kolesnikov
Keyword(s):  
Industrial Development ◽  
Anthropogenic Pollution ◽  
Water Bodies ◽  
Yamal Peninsula ◽  
Household Waste ◽  
Water Protection ◽  
Channel Processes ◽  
Protection Zones ◽  
State Of Water ◽  
The Yamal Peninsula

Most of the population of the Yamal Peninsula lives in settlements located on the banks of rivers. The increasing industrial development of the Yamal Peninsula leads to the fact that in these settlements in the water area and on the shores, objects of the fuel and energy complex are being built and functioning. At the same time, the contribution to water pollution of settlements located here, as well as objects of transport and fuel and energy infrastructure, is still unclear. On the other hand, the issues of intensifying the processes of coastal destruction and the related danger to residential and economic infrastructure are increasingly being discussed. However, the degree of activation of these processes on the Yamal Peninsula is also poorly understood. During the study, the state of water bodies and water protection zones was monitored for the period from 2016 to 2020. It was found that at present no significant anthropogenic pollution of water and bottom sediments is recorded. The content of pollutants and heavy metals is mainly determined by natural conditions. At the same time, the water protection zones are littered with scrap metal and household waste. Activation of channel processes and processes of abrasion and thermal abrasion of the banks is observed. The intensity of coastal destruction processes in the erosion zone varies from 0.25 to 0.85 m/year.

Very High Resolution Analysis of the Dynamics of a Coronal Plasmoid

1994 ◽  
Vol 144 ◽  
pp. 593-596
Author(s):  
O. Bouchard ◽  
S. Koutchmy ◽  
L. November ◽  
J.-C. Vial ◽  
J. B. Zirker
Keyword(s):  
High Resolution ◽  
Solar Eclipse ◽  
Total Solar Eclipse ◽  
Field Of View ◽  
Small Field ◽  
High Resolution Analysis ◽  
Ccd Observations ◽  
Resolution Analysis ◽  
Very High ◽  
Small Field Of View

AbstractWe present the results of the analysis of a movie taken over a small field of view in the intermediate corona at a spatial resolution of 0.5“, a temporal resolution of 1 s and a spectral passband of 7 nm. These CCD observations were made at the prime focus of the 3.6 m aperture CFHT telescope during the 1991 total solar eclipse.

Sign in / Sign up

Export Citation Format

Share Document