scholarly journals Mapping of Spatio-Temporal Changes of Surface Water Using Sentinel-1 SAR Images

2021 ◽  
Vol 906 (1) ◽  
pp. 012059
Author(s):  
L’ubomír Kseňak ◽  
Katarína Pukanská ◽  
Karol Bartoš
Keyword(s):  
Surface Water ◽  
Low Cost ◽  
Synthetic Aperture Radar Image ◽  
Water Bodies ◽  
Hydrological Processes ◽  
Anthropogenic Activity ◽  
Sar Images ◽  
Evaluation Procedures ◽  
Spatio Temporal ◽  
Remote Sensing Methods

Abstract Exploration of surface water bodies and their spatial definition has great importance in water resources management and helps understand hydrological processes in the country. Fast, regular, and effective ways of mapping watercourses and their surroundings through remote sensing methods are crucial tools for capturing change and predicting hazards. The last decades have brought new data products, open-source software, and evaluation procedures that allow low-cost mapping of surface water objects. A widespread and sought-after option for this type of mapping is the use of SAR (Synthetic Aperture Radar) image products. Just through SAR technology that it is possible to identify changes in water in a relatively short time and at the same time under any meteorological conditions thanks to backscattered microwave radiation. This paper presents the possibilities of using SAR technology and its data for long-term temporal mapping of meteorological-hydrological changes in surface water using satellite images of Sentinel-1 product level GRD. As regards surface water extraction, this process is performing by segmenting the threshold values according to the Otsu principle. The water surfaces are then interpreted into the form of water masks of objects by the binarization of the final image. These values are subsequently compared with the supervised classification RFC (Random Forest Classifier) method results. Suitable processing and evaluation procedures conclude that the more suitable polarization configuration for mapping water bodies is VV (vertical-vertical) polarization. As for speckle filter tools to eliminate radar noise, the most suitable option seems to be using a Lee filter. To achieve more accurate results of the extracted water bodies, it is then appropriate to implement quantitative statistical indicators of accuracy and their numerical interpretation of the reliability of results. This paper aims to demonstrate the advantages of using satellite SAR images for spatiotemporal mapping of surface water in the landscape to observe hydrological processes due to inundation, ecological and meteorological changes, and anthropogenic activity.

scholarly journals Hydrogen and Oxygen Isotope Composition and Water Quality Evaluation for Different Water Bodies in the Ebinur Lake Watershed, Northwestern China

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2067 ◽  
Author(s):  
Zhu ◽  
Zhang ◽  
Zhang ◽  
Kung ◽  
Yushanjiang
Keyword(s):  
Surface Water ◽  
River Water ◽  
Major Ions ◽  
Water Bodies ◽  
Northwestern China ◽  
Anthropogenic Activity ◽  
Total Hardness ◽  
Reservoir Water ◽  
Ebinur Lake ◽  
Volatile Phenol

Wetlands are sensitive indicators of climate change and have a profound impact on the supply of water resources in surrounding areas. In this study, the hydrochemical, isotopic characteristics (δ18O and δ2H) of groundwater and surface water (lake, reservoir, and river) in the Ebinur Lake Watershed, northwestern China, were investigated to reveal the relationships between various water bodies. The results suggest that the groundwater is alkaline and has pH and total dissolved solids (TDS) values less than those of surface water. Ca2+ and SO42− are the major ions in the groundwater and river water, whereas lake water and reservoir water are enriched in Na+ and SO42−. With the decrease in elevation, both groundwater and river water are affected by carbonate dissolution at high elevation and by evaporitic rock dissolution at low elevation; thus, the water surrounding Ebinur Lake is subjected to runoff affected by intense evaporation–dissolution of evaporitic rocks. The stable isotope compositions suggested that the upstream part of the river is recharged by glacial meltwater from high mountains, whereas the middle–downstream parts of the river are recharged by low-elevation precipitation. Shallow groundwater and reservoir water are mainly recharged by river water and are more enriched in the downstream part of river. Water samples were also classified according to different indices, such as chemical oxygen demand (COD), NH3-N, volatile phenol, sulfate, Zn, Co, Cu, total hardness, and Cr6+, and results showed that most groundwater is suitable for drinking and irrigation purposes. Except for Cr6+, the metal concentrations are within permissible limits. However, both groundwater and reservoir water are affected to some extent by nearby rivers from anthropogenic activity.

scholarly journals Spatio-temporal Effect of Urbanization on Surface Water Bodies: A Method of RS and GIS

2016 ◽  
Vol 10 (1) ◽  
pp. 489-499 ◽  
Author(s):  
Jianfeng Zhu ◽  
Qiuwen Zhang ◽  
Zhong Tong ◽  
Xiaofei Liu ◽  
Fei Yan
Keyword(s):  
Land Use ◽  
Surface Water ◽  
Urban Expansion ◽  
Land Use Changes ◽  
Water Bodies ◽  
Surface Water Resources ◽  
Rs And Gis ◽  
Resource Managers ◽  
Surface Water Bodies ◽  
Spatio Temporal

This paper focuses on the spatio-temporal effects of urbanization on surface water resources in Wuhan, China. Specifically, the relationships between surface water bodies and their surrounding land use changes are discussed quantitatively by remote sensing (RS) and geographic information system (GIS). In this paper, surface water bodies and land use classifications in 1991 and 2005 are detected from Landsat TM/ETM+ images. On this basis, the area changes of water bodies and their transformations are extracted by overlap analysis. The result proves that most of the reduced surface water bodies had transformed into developed land in the urban districts. Finally, a comparative analysis indicates that the rate of increment of developed land in 100 m buffer (14%) is higher than in 1000 m buffer (8.8%). In other words, urban development is growing towards water bodies as urbanization. Therefore, the effects of urbanization on surface water bodies can be summarized as follows: (1) water bodies are likely to be occupied directly by developed land with urbanization; (2) the space of surface water is compressed due to urban expansion. This paper would provide a suggestion for urban planners and water resource managers.

scholarly journals RASPBERRY PI 3 MULTISPECTRAL LOW-COST SENSOR FOR UAV BASED REMOTE SENSING. CASE STUDY IN SOUTH-WEST NIGER

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 207-214 ◽  
Author(s):  
E. Belcore ◽  
M. Piras ◽  
A. Pezzoli ◽  
G. Massazza ◽  
M. Rosso
Keyword(s):  
Surface Water ◽  
Low Cost ◽  
Water Bodies ◽  
Raspberry Pi ◽  
Water Index ◽  
Critical Areas ◽  
South West ◽  
Normalized Difference Water Index ◽  
Surface Water Bodies

<p><strong>Abstract.</strong> The technology of UAV (Unmanned Aerial Vehicles) is rapidly improving and UAV-integrated sensors have kept up with it, providing more efficient and effective solutions. One of the most sought-after characteristics of on-board sensors is the low costing associated to good quality of the collected data. This paper proposes a very low-cost multiband sensor developed on a Raspberry device and two Raspberry Pi 3 cameras that can be used in photogrammetry from drone applications. The UAV-integrated radiometric sensor and its performance were tested in in two villages of South-west Niger for the detection of temporary surface water bodies (or Ephemeral water bodies): zones of seasonal stagnant water within villages threatening the viability and people’s health. The Raspberry Pi 3 cameras employed were a regular RGB Pi camera 2 (Red, Green, Blue) and a NoIR Pi 3 camera v2 (regular RGB without IR filter) with 8MPX resolution. The cameras were geometrically calibrated and radiometrically tested before the survey in the field. The results of the photogrammetry elaborations were 4 orthophotos (a RGB and NoIRGB orthophoto for each village). The Normalized Difference Water Index (NDWI) was calculated. The index allowed the localization and the contouring of the temporary surface water bodies present in the villages. The data were checked against the data collected with a Sony (ILCE-5100). Very high correspondence between the different data was detected. Raspberry-based sensors demonstrated to be a valid tool for the data collection in critical areas.</p>

Ecological and hygienic assessment pollution of surface and groundwater in Transural Region Republic of Bashkortostan

2017 ◽  
pp. 14-17
Author(s):  
Z.B. Baktybaeva ◽  
R.A. Suleymanov ◽  
T.K. Valeev ◽  
N.R. Rakhmatullin
Keyword(s):  
Surface Water ◽  
Calcium Nitrate ◽  
Water Bodies ◽  
Drinking Water Contamination ◽  
Mining Areas ◽  
Relative Contribution ◽  
Quality Of Water ◽  
Republic Of Bashkortostan ◽  
The Republic ◽  
Surface And Groundwater

Carried out ecological and hygienic assessment of pollution of surface and groundwater of mining areas in the Republic of Bashkortostan. Revealed exceeding standards for fishery water bodies and drinking and cultural and community water use, which indicates the potential danger of surface water for the health of the region's population. The greatest relative contribution to the overall pollution of surface water bodies are making manganese (33,0–66,6 %), iron (9,1–15,6 %), calcium (6,5–11,7 %), lead (5,8– 7,2 %). The quality of water used for drinking purposes from decentralized water sources (boreholes, wells, springs), do not always correspond to the hygienic and sanitary-epidemiological requirements. In this case, the highest priority performance of drinking water contamination are increased stiffness, high content of iron, calcium, nitrate, presence cadmium, and hexavalent chromium.

scholarly journals Biomechanics of Trail Running Performance: Quantification of Spatio-Temporal Parameters by Using Low Cost Sensors in Ecological Conditions

2021 ◽  
Vol 11 (5) ◽  
pp. 2093
Author(s):  
Noé Perrotin ◽  
Nicolas Gardan ◽  
Arnaud Lesprillier ◽  
Clément Le Goff ◽  
Jean-Marc Seigneur ◽  
...  
Keyword(s):  
Heart Rate ◽  
Low Cost ◽  
Step Length ◽  
Measurement Unit ◽  
Ecological Conditions ◽  
Sports Science ◽  
Ground Contact Time ◽  
Spatio Temporal ◽  
Performance Results ◽  
Trail Running

The recent popularity of trail running and the use of portable sensors capable of measuring many performance results have led to the growth of new fields in sports science experimentation. Trail running is a challenging sport; it usually involves running uphill, which is physically demanding and therefore requires adaptation to the running style. The main objectives of this study were initially to use three “low-cost” sensors. These low-cost sensors can be acquired by most sports practitioners or trainers. In the second step, measurements were taken in ecological conditions orderly to expose the runners to a real trail course. Furthermore, to combine the collected data to analyze the most efficient running techniques according to the typology of the terrain were taken, as well on the whole trail circuit of less than 10km. The three sensors used were (i) a Stryd sensor (Stryd Inc. Boulder CO, USA) based on an inertial measurement unit (IMU), 6 axes (3-axis gyroscope, 3-axis accelerometer) fixed on the top of the runner’s shoe, (ii) a Global Positioning System (GPS) watch and (iii) a heart belt. Twenty-eight trail runners (25 men, 3 women: average age 36 ± 8 years; height: 175.4 ± 7.2 cm; weight: 68.7 ± 8.7 kg) of different levels completed in a single race over a 8.5 km course with 490 m of positive elevation gain. This was performed with different types of terrain uphill (UH), downhill (DH), and road sections (R) at their competitive race pace. On these sections of the course, cadence (SF), step length (SL), ground contact time (GCT), flight time (FT), vertical oscillation (VO), leg stiffness (Kleg), and power (P) were measured with the Stryd. Heart rate, speed, ascent, and descent speed were measured by the heart rate belt and the GPS watch. This study showed that on a ≤10 km trail course the criteria for obtaining a better time on the loop, determined in the test, was consistency in the effort. In a high percentage of climbs (>30%), two running techniques stand out: (i) maintaining a high SF and a short SL and (ii) decreasing the SF but increasing the SL. In addition, it has been shown that in steep (>28%) and technical descents, the average SF of the runners was higher. This happened when their SL was shorter in lower steep and technically challenging descents.

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