To see the other types of publications on this topic, follow the link: Water Band Index (WBI).
Journal articles on the topic 'Water Band Index (WBI)'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Water Band Index (WBI).'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Badzmierowski, McCall, and Evanylo. "Using Hyperspectral and Multispectral Indices to Detect Water Stress for an Urban Turfgrass System." Agronomy 9, no. 8 (August 8, 2019): 439. http://dx.doi.org/10.3390/agronomy9080439.
Full textAbstract:
Spectral reflectance measurements collected from hyperspectral and multispectral radiometers have the potential to be a management tool for detecting water and nutrient stress in turfgrass. Hyperspectral radiometers collect hundreds of narrowband reflectance data compared to multispectral radiometers that collect three to ten broadband reflectance data for a cheaper cost. Spectral reflectance data have been used to create vegetation indices such as the normalized difference vegetation index (NDVI) and the simple ratio vegetation index (RVI) to assess crop growth, density, and fertility. Other indices such as the water band index (WBI) (narrowband index) and green-to-red ratio index (GRI) (both broadband and narrowband index) have been proposed to predict soil moisture status in turfgrass systems. The objective of this study was to compare the value of multispectral and hyperspectral radiometers to assess soil volumetric water content (VWC) and tall fescue (Festuca arundinacea Schreb.) responses. The multispectral radiometer VI had the strongest relationships to turfgrass quality, biomass, and tissue N accumulation during the trial period (April 2017–August 2018). Soil VWC had the strongest relationship to WBI (r = 0.60), followed by GRI and NDVI (both r = 0.54) for the 0% evapotranspiration (ET). Nonlinear regression showed strong relationships at high water stress periods in each year for WBI (r = 0.69–0.79), GRI (r = 0.64–0.75), and NDVI (r = 0.58–0.79). Broadband index data collected using a mobile multispectral sensor is a cheaper alternative to hyperspectral radiometry and can provide better spatial coverage.
2
Sovoe, S. "Mapping Irrigated Area Fragments for Crop Water Use Assessment Using Handheld Spectroradiometer." International Journal of Agronomy 2011 (2011): 1–8. http://dx.doi.org/10.1155/2011/974040.
Full textAbstract:
As climatic change and land use are altering the hydrographic regime, most catchments are progressively becoming drier and farmers are shifting from rainfed agriculture to irrigation practices to enable them to carry out income-generating activities throughout the year. The Ghanaian government has recently been promoting irrigation agricultural practices as the population keeps increasing and the demand for food keeps soaring. In order to keep pace with high demand for food coupled with increasing aridity of the subregion, some farmers resort to informal irrigation practices. In this study, hyperspectral reflectance data of the irrigated crops under informal practices were collected to assess their efficiency of water use. Photochemical reflectance index (PRI), soil-specific nitrogen index (SSN), and water band index (WBI) were computed. ThePRIandWBIwere significantly correlated, while there was no significant correlation betweenPRIandSSN. The map showing the probability of water stress indicated that informal irrigation practices are not an efficient water management approaches.
3
Devitt, D. A., R. L. Morris, and L. K. Fenstermaker. "Foliar Damage, Spectral Reflectance, and Tissue Ion Concentrations of Trees Sprinkle Irrigated with Waters of Similar Salinity but Different Chemical Composition." HortScience 40, no. 3 (June 2005): 819–26. http://dx.doi.org/10.21273/hortsci.40.3.819.
Full textAbstract:
We investigated foliar damage to five landscape species sprinkler irrigated with either reuse water or one of five synthesized saline waters that contained elevated single salts mixed with Colorado River water, all having similar electrical conductivities. The experiment allowed us to compare the impact of elevated concentrations of Na, Mg, Ca, Cl, and SO4 on an index of visual damage (IVD), tissue ion concentrations, and spectral reflectance. Waters containing elevated concentrations of MgCl2 or NaCl caused greater foliar damage than did MgSO4, Na2SO4, CaSO4, or reuse water, as recorded in higher IVD values (p < 0.05). Privet and elm were damaged to a greater extent (higher IVD values) than were desert willow, guava and laurel (p < 0.05). Higher IVD values were recorded for all species irrigated with the MgCl2 waters, with mortality recorded in privet. Tissue nutrient concentrations were correlated with the IVD values. In the case of guava, 61% of the variability in the IVD could be accounted for based on N, P and K (P < 0.01). On a treatment basis, the single salts added to the municipal water showed little correlation with the IVD values, except in the case of MgCl2, where Mg was included in the regression equation (r2 = 0.82, P < 0.01, IVD↑ as S04↓, Mg and P↑). Eleven different spectral indices separated based on treatment and/or species (P < 0.05). In elm, 70% of the variability in the IVD could be accounted for by including Red Edge, Normalized Difference Vegetation Index (NDVI) and Water Band Index (WBI)/NDVI. A mixed response was observed to a post 30-day irrigation rinse in an attempt to reduce IVD values. Based on our results, care should be given to monitoring not only the EC (and osmotic potential) but also the ionic composition when saline waters are blended with other water sources, with the aim of minimizing the concentration of Mg, Cl, and Na.
4
Rastogi, Anshu, Subhajit Bandopadhyay, Marcin Stróżecki, and Radosław Juszczak. "Monitoring the Impact of Environmental Manipulation on Peatland Surface by Simple Remote Sensing Indices." ITM Web of Conferences 23 (2018): 00030. http://dx.doi.org/10.1051/itmconf/20182300030.
Full textAbstract:
The behaviour of nature depends on the different components of climates. Among these, temperature and rainfall are two of the most important components which are known to change plant productivity. Peatlands are among the most valuable ecosystems on the Earth, which is due to its high biodiversity, huge soil carbon storage, and its sensitivity to different environmental factors. With the rapid growth in industrialization, the climate change is becoming a big concern. Therefore, this work is focused on the behaviour of Sphagnum peatland in Poland, subjected to environment manipulation. Here it has been shown how a simple reflectance based technique can be used to assess the impact of climate change on peatland. The experimental setup consists of four plots with two kind of manipulations (control, warming, reduced precipitation, and a combination of warming and reduced precipitation). Reflectance data were measured twice in August 2017 under a clear sky. Vegetation indices (VIs) such as Normalized Difference Vegetation Index (NDVI), Photochemical Reflectance Index (PRI), near-infrared reflectance of vegetation (NIRv), MERIS terrestrial chlorophyll index (MTCI), Green chlorophyll index (CIgreen), Simple Ration (SR), and Water Band Index (WBI) were calculated to trace the impact of environmental manipulation on the plant community. Leaf Area Index of vascular plants was also measured for the purpose to correlate it with different VIs. The observation predicts that the global warming of 1°C may cause a significant change in peatland behaviour which can be tracked and monitored by simple remote sensing indices.
5
Devitt, D. A., R. L. Morris, L. K. Fenstermaker, M. Baghzouz, and D. S. Neuman. "Foliar Damage and Flower Production of Landscape Plants Sprinkle Irrigated with Reuse Water." HortScience 40, no. 6 (October 2005): 1871–78. http://dx.doi.org/10.21273/hortsci.40.6.1871.
Full textAbstract:
Nineteen flowering landscape species were sprinkle irrigated with either reuse water or fresh water, with an additional treatment of reuse water plus shade (solar radiation reduced by 24%), for 113 days during late summer and early fall in southern Nevada. The species selected were common to mixed landscape areas on golf courses in southern Nevada transitioning to reuse water. An index of visual damage (IVD) was assessed, along with an assessment of flower production, canopy temperature, tissue ion analysis and spectral reflectance. The IVD values separated based on species (p < 0.001), treatment (p < 0.001) and by a species by treatment interaction (p < 0.001). Irrigating with reuse water plus shade reduced the IVD compared to the reuse without shade in 7 of the 19 species (p < 0.05). When IVD values were included for all species, 40% of the variation in the IVD values could be accounted for if N, B, Ca, Mg, Na, and Zn were included in the regression equation. Higher r2 values were obtained when individual species were isolated, with regression equations differing based on tissue ion combinations [e.g., ice plant (Mesembryanthemum crystallinum L.) r2 = 0.81 IVD↑, Na↓, Mn↑]. Three vegetation indices chlorophyll index (CHL), red/far red (R/FR) and water band index/normalized difference vegetation index (WBI/NDVI)) accounted for 51% of the variation in the IVD values. As much as 72% of the variation in vegetation indices could be accounted for based on tissue ion concentrations when separated based on treatment, with Na being the only common ion in all of the highest correlations. Flower production was highest in the reuse plus shade treatment in all 13 species flowering during the experimental period, with as much as 86% of the flower production variation driven by different tissue ion concentrations [purple cup (Nierembergia hippomanica), r2 = 0.86, flowers↑, Mn↑, Zn↓]. Nine of the nineteen species had acceptable levels of foliar damage (IVD < 2.0). We believe that if the spray irrigation can be minimized (bubblers/drip) and/or partial shade provided, through multi-story landscape designs, a more favorable response will be observed.
6
Skoczowski, Andrzej, Magdalena Odrzywolska-Hasiec, Jakub Oliwa, Iwona Ciereszko, and Andrzej Kornaś. "Ecophysiological Variability of Alnus viridis (Chaix) DC. Green Alder Leaves in the Bieszczady Mountains (Poland)." Plants 10, no. 1 (January 6, 2021): 96. http://dx.doi.org/10.3390/plants10010096.
Full textAbstract:
Alnus viridis (Chaix) DC., green alder, is a fast-growing shrub that grows expansively in the European mountainside. In Poland, A. viridis naturally occurs only in the Bieszczady Mountains (south-eastern part of the country), above the upper forest border. In this study, we assessed the potential of green alder to expand in post-farming areas in the Bieszczady Mountains. We investigated the effects of topographical, climatic, and edaphic characteristics of four various study sites on the physiological and morphological properties of A. viridis leaves in order to answer the question whether the growth of plants in lower positions improves their physiological condition to such an extent that it increases the species invasiveness. This is the first comprehensive ecophysiological study of this species to be carried out in this part of Europe. The photochemical efficiency of PSII, the chlorophyll content, and leaf 13C and 15N discrimination were analyzed. On the basis of leaf radiation reflection, coefficients such as reflectance indices of anthocyanins, carotenoids, flavonoids (ARI2, CRI1, FRI), photochemical index of reflection (PRI), and the water band index (WBI) were calculated. We observed favorable physiological effects in A. viridis plants growing in locations below the upper forest border compared to plants growing in higher locations. As a result, A. viridis may become an invasive species and disturb the phytocoenotic balance of plant communities of the altitudinal zones in the Polish Western Carpathians.
7
Kim, Dongjin, Yasuyuki Yamamoto, Shijo Nagao, Naoki Wakasugi, Chuantong Chen, and Katsuaki Suganuma. "Measurement of Heat Dissipation and Thermal-Stability of Power Modules on DBC Substrates with Various Ceramics by SiC Micro-Heater Chip System and Ag Sinter Joining." Micromachines 10, no. 11 (October 31, 2019): 745. http://dx.doi.org/10.3390/mi10110745.
Full textAbstract:
This study introduced the SiC micro-heater chip as a novel thermal evaluation device for next-generation power modules and to evaluate the heat resistant performance of direct bonded copper (DBC) substrate with aluminum nitride (AlN-DBC), aluminum oxide (DBC-Al2O3) and silicon nitride (Si3N4-DBC) ceramics middle layer. The SiC micro-heater chips were structurally sound bonded on the two types of DBC substrates by Ag sinter paste and Au wire was used to interconnect the SiC and DBC substrate. The SiC micro-heater chip power modules were fixed on a water-cooling plate by a thermal interface material (TIM), a steady-state thermal resistance measurement and a power cycling test were successfully conducted. As a result, the thermal resistance of the SiC micro-heater chip power modules on the DBC-Al2O3 substrate at power over 200 W was about twice higher than DBC-Si3N4 and also higher than DBC-AlN. In addition, during the power cycle test, DBC-Al2O3 was stopped after 1000 cycles due to Pt heater pattern line was partially broken induced by the excessive rise in thermal resistance, but DBC-Si3N4 and DBC-AlN specimens were subjected to more than 20,000 cycles and not noticeable physical failure was found in both of the SiC chip and DBC substrates by a x-ray observation. The results indicated that AlN-DBC can be as an optimization substrate for the best heat dissipation/durability in wide band-gap (WBG) power devices. Our results provide an important index for industries demanding higher power and temperature power electronics.
8
Li, Kaiwei, Chunyi Wang, Qing Sun, Guangzhi Rong, Zhijun Tong, Xingpeng Liu, and Jiquan Zhang. "Spring Phenological Sensitivity to Climate Change in the Northern Hemisphere: Comprehensive Evaluation and Driving Force Analysis." Remote Sensing 13, no. 10 (May 18, 2021): 1972. http://dx.doi.org/10.3390/rs13101972.
Full textAbstract:
Plant phenology depends largely on temperature, but temperature alone cannot explain the Northern Hemisphere shifts in the start of the growing season (SOS). The spatio–temporal distribution of SOS sensitivity to climate variability has also changed in recent years. We applied the partial least squares regression (PLSR) method to construct a standardized SOS sensitivity evaluation index and analyzed the combined effects of air temperature (Tem), water balance (Wbi), radiation (Srad), and previous year’s phenology on SOS. The spatial and temporal distributions of SOS sensitivity to Northern Hemisphere climate change from 1982 to 2014 were analyzed using time windows of 33 and 15 years; the dominant biological and environmental drivers were also assessed. The results showed that the combined sensitivity of SOS to climate change (SCom) is most influenced by preseason temperature sensitivity. However, because of the asymmetric response of SOS to daytime/night temperature (Tmax/Tmin) and non-negligible moderating of Wbi and Srad on SOS, SCom was more effective in expressing the effect of climate change on SOS than any single climatic factor. Vegetation cover (or type) was the dominant factor influencing the spatial pattern of SOS sensitivity, followed by spring temperature (Tmin > Tmax), and the weakest was water balance. Forests had the highest SCom absolute values. A significant decrease in the sensitivity of some vegetation (22.2%) led to a decreasing trend in sensitivity in the Northern Hemisphere. Although temperature remains the main climatic factor driving temporal changes in SCom, the temperature effects were asymmetric between spring and winter (Tems/Temw). More moisture might mitigate the asymmetric response of SCom to spring/winter warming. Vegetation adaptation has a greater influence on the temporal variability of SOS sensitivity relative to each climatic factor (Tems, Temw, Wbi, Srad). More moisture might mitigate the asymmetric response of SCom to spring/winter warming. This study provides a basis for vegetation phenology sensitivity assessment and prediction.
9
Wang, Zifeng, Junguo Liu, Jinbao Li, and David Zhang. "Multi-Spectral Water Index (MuWI): A Native 10-m Multi-Spectral Water Index for Accurate Water Mapping on Sentinel-2." Remote Sensing 10, no. 10 (October 16, 2018): 1643. http://dx.doi.org/10.3390/rs10101643.
Full textAbstract:
Accurate water mapping depends largely on the water index. However, most previously widely-adopted water index methods are developed from 30-m resolution Landsat imagery, with low-albedo commission error (e.g., shadow misclassified as water) and threshold instability being identified as the primary issues. Besides, since the shortwave-infrared (SWIR) spectral band (band 11) on Sentinel-2 is 20 m spatial resolution, current SWIR-included water index methods usually produce water maps at 20 m resolution instead of the highest 10 m resolution of Sentinel-2 bands, which limits the ability of Sentinel-2 to detect surface water at finer scales. This study aims to develop a water index from Sentinel-2 that improves native resolution and accuracy of water mapping at the same time. Support Vector Machine (SVM) is used to exploit the 10-m spectral bands among Sentinel-2 bands of three resolutions (10-m; 20-m; 60-m). The new Multi-Spectral Water Index (MuWI), consisting of the complete version and the revised version (MuWI-C and MuWI-R), is designed as the combination of normalized differences for threshold stability. The proposed method is assessed on coincident Sentinel-2 and sub-meter images covering a variety of water types. When compared to previous water indexes, results show that both versions of MuWI enable to produce native 10-m resolution water maps with higher classification accuracies (p-value < 0.01). Commission and omission errors are also significantly reduced particularly in terms of shadow and sunglint. Consistent accuracy over complex water mapping scenarios is obtained by MuWI due to high threshold stability. Overall, the proposed MuWI method is applicable to accurate water mapping with improved spatial resolution and accuracy, which possibly facilitates water mapping and its related studies and applications on growing Sentinel-2 images.
10
Reddy, S. L. K., C. V. Rao, P. R. Kumar, R. V. G. Anjaneyulu, and B. G. Krishna. "A NOVEL METHOD FOR WATER AND WATER CANAL EXTRACTION FROM LANDSAT-8 OLI IMAGERY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-5 (November 19, 2018): 323–28. http://dx.doi.org/10.5194/isprs-archives-xlii-5-323-2018.
Full textAbstract:
<p><strong>Abstract.</strong> Constituents of hydrologic network, River and water canals play a key role in Agriculture for cultivation, Industrial activities and urban planning. Remote sensing images can be effectively used for water canal extraction, which significantly improves the accuracy and reduces the cost involved in mapping using conventional means. Using remote sensing data, the water Index (WI), Normalized Difference Water Index (NDWI) and Modified NDWI (MNDWI) are used in extracting the water bodies. These techniques are aimed at water body detection and need to be complemented with additional information for the extraction of complete water canal networks. The proposed index MNDWI-2 is able to find the water bodies and water canals as well from the Landsat-8 OLI imagery and is based on the SWIR2 band. In this paper, we use Level-1 precision terrain corrected OLI imagery at 30 meter spatial resolution. The proposed MNDWI-2 index is derived using SWIR2 (B7) band and Green (B3) band. The usage of SWIR2 band over SWIR1 results in very low reflectance values for water features, detection of shallow water and delineation of water features with rest of the features in the image. The computed MNDWI-2 index values are threshold by making the values greater than zero as 1 and less than zero as zero. The binarised values of 1 represent the water bodies and 0 represent the non-water body. This normalized index detects the water bodies and canals as well as vegetation which appears in the form of noise. The vegetation from the MNDWI-2 image is removed by using the NDVI index, which is calculated using the Top of Atmosphere (TOA) corrected images. The paper presents the results of water canal extraction in comparison with the major available indexes. The proposed index can be used for water and water canal extraction from L8 OLI imagery, and can be extended for other high resolution sensors.</p>
11
Jiang, Wei, Yuan Ni, Zhiguo Pang, Xiaotao Li, Hongrun Ju, Guojin He, Juan Lv, Kun Yang, June Fu, and Xiangdong Qin. "An Effective Water Body Extraction Method with New Water Index for Sentinel-2 Imagery." Water 13, no. 12 (June 11, 2021): 1647. http://dx.doi.org/10.3390/w13121647.
Full textAbstract:
Surface water bodies, such as rivers, lakes, and reservoirs, play an irreplaceable role in global ecosystems and climate systems. Sentinel-2 imagery provides new high-resolution satellite remote sensing data. Based on the analysis of the spectral characteristics of the Sentinel-2 satellite, a novel water index called the Sentinel-2 water index (SWI) that is based on the vegetation-sensitive red-edge band (Band 5) and shortwave infrared (Band 11) bands was developed. Four representative water body types, namely, Taihu Lake, Yangtze River, Chaka Salt Lake, and Chain Lake, were selected as study areas to conduct a water body extraction performance comparison with the normalized difference water index (NDWI). We found that (1) the contrast value of the SWI was larger than that of the NDWI in terms of various water body types, including purer water, turbid water, salt water, and floating ice, which suggested that the SWI could achieve better enhancement performance for water bodies. An (2) effective water body extraction method was proposed by integrating the SWI and Otsu algorithm, which could accurately extract various water body types with high overall accuracy. The (3) method effectively extracted large water bodies and wide river channels by suppressing shadow noise in urban areas. Our results suggested that the novel method can achieve efficient water body extraction for rapidly and accurately extracting various water bodies from Sentinel-2 data and the novel method has application potential for larger-scale surface water mapping.
12
Yousefian, F., M. Sahebi, M. Shokri, and M. Moradi. "A NOVEL WATER INDEX (SWI) FOR SALTY WATER FROM LANDSAT 8 OLI/TIRS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W18 (October 19, 2019): 1097–105. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w18-1097-2019.
Full textAbstract:
Abstract. Monitoring natural resources is one of the most important tasks in earth observation and remote sensing satellites. Water resources play a crucial role in the life of human on the planet. Among the water resources, salty lakes are of particular importance in biological, physical and environmental issues. In this study, a new Salty Water Index (SWI) for Landsat 8 Operational Land Imager (OLI) images is proposed based on salty lakes by particle swarm optimization (PSO), where water doesn’t combine by cloud, shadow, and salty areas. SWI is implemented on four famous and important salty lakes with the proper distribution of the whole world and different Salinity, including Lake Assal, Great Salt Lake, Eyre Lake, and Lake Urmia. The performance of SWI is compared with other water indices by overall accuracy, f-score, kappa coefficient, and standard deviation to mean ratio. Results show the efficiency of SWI on all cases due to 0.0055 Standard deviation to mean for SWI compared to 0.0395, 0.0255, 0.0873, 0.0214, 0.0524, 0.0408 and 0.0375 for NDWI, MNDWI, AWEIsh, AWEI, WRI, MOWI, and MBWI, respectively. Also, Effectiveness criteria (E) determines the efficiency of each band of Landsat 8. In this regard, results show the high performance of Green and Near IR band in all conditions and relatively proper performance of some other bands based on a special condition of each case study. The proposed method is also suggested to readers to obtain novel spectral indices of other classes and other sensors.
13
Huang, Yuancheng, Jeffrey P. Walker, Ying Gao, Xiaoling Wu, and Alessandra Monerris. "Estimation of Vegetation Water Content From the Radar Vegetation Index at L-Band." IEEE Transactions on Geoscience and Remote Sensing 54, no. 2 (February 2016): 981–89. http://dx.doi.org/10.1109/tgrs.2015.2471803.
Full text
14
Xie, Cong, Xin Huang, Wenxian Zeng, and Xing Fang. "A novel water index for urban high-resolution eight-band WorldView-2 imagery." International Journal of Digital Earth 9, no. 10 (April 22, 2016): 925–41. http://dx.doi.org/10.1080/17538947.2016.1170215.
Full text
15
Pan, Feifei, Xiaohuan Xi, and Cheng Wang. "A Comparative Study of Water Indices and Image Classification Algorithms for Mapping Inland Surface Water Bodies Using Landsat Imagery." Remote Sensing 12, no. 10 (May 18, 2020): 1611. http://dx.doi.org/10.3390/rs12101611.
Full textAbstract:
A comparative study of water indices and image classification algorithms for mapping inland water bodies using Landsat imagery was carried out through obtaining 24 high-resolution (≤5 m) and cloud-free images archived in Google Earth with the same (or ±1 day) acquisition dates as the Landsat-8 OLI images over 24 selected lakes across the globe, and developing a method to generate the alternate ground truth data from the Google Earth images for properly evaluating the Landsat image classification results. In addition to the commonly used green band-based water indices, Landsat-8 OLI’s ultra-blue, blue, and red band-based water indices were also tested in this research. Two unsupervised (the zero-water index threshold H0 method and Otsu’s automatic threshold selection method) and one supervised (the k-nearest neighbor (KNN) method) image classification algorithms were employed for conducting the image classification. Through comparing a total of 2880 Landsat image classification results with the alternate ground truth data, this study showed that (1) it is not necessary to use some supervised image classification methods for extracting water bodies from Landsat imagery given the high computational cost associated with the supervised image classification algorithms; (2) the unsupervised classification algorithms such as the H0 and Otsu methods could achieve comparable accuracy as the KNN method, although the H0 method produced more large error outliers than the Otsu method, thus the Otsu method is better than the H0 method; and (3) the ultra-blue band-based AWEInsuB is the best water index for the H0 method, and the ultra-blue band-based MNDWI2uB is the best water index for both the Otsu and KNN methods.
16
Ji, Huiping, Gonghuan Fang, Jing Yang, and Yaning Chen. "Multi-Objective Calibration of a Distributed Hydrological Model in a Highly Glacierized Watershed in Central Asia." Water 11, no. 3 (March 17, 2019): 554. http://dx.doi.org/10.3390/w11030554.
Full textAbstract:
Understanding glacio-hydrological processes is crucial to water resources management, especially under increasing global warming. However, data scarcity makes it challenging to quantify the contribution of glacial melt to streamflow in highly glacierized catchments such as those in the Tienshan Mountains. This study aims to investigate the glacio-hydrological processes in the SaryDjaz-Kumaric River (SDKR) basin in Central Asia by integrating a degree-day glacier melt algorithm into the macro-scale hydrological Soil and Water Assessment Tool (SWAT) model. To deal with data scarcity in the alpine area, a multi-objective sensitivity analysis and a multi-objective calibration procedure were used to take advantage of all aspects of streamflow. Three objective functions, i.e., the Nash–Sutcliffe efficiency coefficient of logarithms (LogNS), the water balance index (WBI), and the mean absolute relative difference (MARD), were considered. Results show that glacier and snow melt-related parameters are generally sensitive to all three objective functions. Compared to the original SWAT model, simulations with a glacier module match fairly well to the observed streamflow, with the Nash–Sutcliffe efficiency coefficient (NS) and R2 approaching 0.82 and an absolute percentage bias less than 1%. Glacier melt contribution to runoff is 30–48% during the simulation period. The approach of combining multi-objective sensitivity analysis and optimization is an efficient way to identify important hydrological processes and recharge characteristics in highly glacierized catchments.
17
Wen, Xing Ping, and Xiao Feng Yang. "Monitoring of Water Quality Using Remote Sensing Techniques." Applied Mechanics and Materials 29-32 (August 2010): 2360–64. http://dx.doi.org/10.4028/www.scientific.net/amm.29-32.2360.
Full textAbstract:
Remote sensing techniques play increasingly important role over recent decades in both problems of global climate change and frequent deterioration of the status of aquatic ecology. In this paper, Landsat ETM+ imagery was used to monitors water quality in Kunming city, southwest China. Five over 30 square kilometers lakes which are Dianchi, Fuxian, Yangzong, Qilu and Xingyun Lake were extracted and investigated. Comparing spectra of different water quality, it can be conclude the reflectance of band 2 and band 3 change dramaticlly corresponding to different water quality, which are relate to the water pollutant. Therefore, the sum of band 2 and band 3 reflectance used as a water quality index was selected to detect water quality. Firstly, the remote sensing data was atmospheric corrected and the reflectance of band 2 and band 3 was added using band math. Secondly, density slice was applied to the processed sum image using suitable data ranges and colors, and six water quality level was outputed. Finally, the result image was projected and outputed. As shown from result, the water quality of Fuxian and Yangzong lake were the best, and Dianchi and Xingyun lake were the worst, Qilu lake was in the middle. Suitable water pollution controls and provention for Kunming lakes would be needed.
18
CLAUDIO, H., Y. CHENG, D. FUENTES, J. GAMON, H. LUO, W. OECHEL, H. QIU, A. RAHMAN, and D. SIMS. "Monitoring drought effects on vegetation water content and fluxes in chaparral with the 970 nm water band index." Remote Sensing of Environment 103, no. 3 (August 15, 2006): 304–11. http://dx.doi.org/10.1016/j.rse.2005.07.015.
Full text
19
Wang, Xiaobiao, Shunping Xie, Xueliang Zhang, Cheng Chen, Hao Guo, Jinkang Du, and Zheng Duan. "A robust Multi-Band Water Index (MBWI) for automated extraction of surface water from Landsat 8 OLI imagery." International Journal of Applied Earth Observation and Geoinformation 68 (June 2018): 73–91. http://dx.doi.org/10.1016/j.jag.2018.01.018.
Full text
20
Iwata, Tetsuo, Jun Koshoubu, Chihiro Jin, and Yusei Okubo. "Temperature Dependence of the Mid-Infrared OH Spectral Band in Liquid Water." Applied Spectroscopy 51, no. 9 (September 1997): 1269–75. http://dx.doi.org/10.1366/0003702971942196.
Full textAbstract:
We have studied the temperature dependence (14–57 °C) of the OH-stretching vibration band in liquid water by the use of a microscope Fourier transform infrared (FT-IR) instrument with an attenuated total reflection (ATR) cell. In order to eliminate spectral distortions, we performed Kramers–Kronig transform of the ATR spectra and derived absorption- and refractive-index spectra. The numerical values are shown in detail. Application of principal component analysis (PCA) and partial least-squares 1 (PLS 1) modeling methods to the absorption-index spectra shows that the OH band consists of two abstract spectral components. The intensity of the first component changes linearly with temperature, whereas the second component changes nonlinearly, with a turning temperature around 30 °C. Each abstract spectrum has a pair of peaks, the intensities of which vary in an inverse manner with respect to each other for the temperature change.
21
Jiang, W., Y. Ni, Z. Pang, G. He, J. Fu, J. Lu, K. Yang, T. Long, and T. Lei. "A NEW INDEX FOR IDENTIFYING WATER BODY FROM SENTINEL-2 SATELLITE REMOTE SENSING IMAGERY." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences V-3-2020 (August 3, 2020): 33–38. http://dx.doi.org/10.5194/isprs-annals-v-3-2020-33-2020.
Full textAbstract:
Abstract. Water body plays an irreplaceable role in the global ecosystem and climate system. Sentinel-2 is a new satellite data with higher spatial and spectral resolution. Through analysing spectral characteristics of Sentinel-2 satellite imagery, the brightness of water body in vegetation red edge band and shortwave infrared band showe sharply different than that of the not water body. Therefore, a new type of water index SWI (Sentinel-2 Water Index) was proposed by combing those two bands. Four representative water types, which included Taihu Lake, the Yangtze River Estuary, the ChaKa Salt Lake and the Chain Lake, were selected as experimental areas. Normalized difference water index (NDWI) and Sentinel-2 Water Index (SWI) with Otsu method were employed to extract water body. The results showed that overall accuracy and Kappa coefficient of SWI were higher than that of NDWI and SWI was efficient index to rapidly and accurately extract water for Sentinel-2 data. Therefore, SWI had application potential for larger scale water mapping in the future.
22
Moradi, M., M. Sahebi, and M. Shokri. "MODIFIED OPTIMIZATION WATER INDEX (MOWI) FOR LANDSAT-8 OLI/TIRS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W4 (September 27, 2017): 185–90. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w4-185-2017.
Full textAbstract:
Water is one of the most important resources that essential need for human life. Due to population growth and increasing need of human to water, proper management of water resources will be one of the serious challenges of next decades. Remote sensing data is the best way to the management of water resources due time and cost effectiveness over a greater range of temporal and spatial scales. Between many kinds of satellite data, from SAR to optic or from high resolution to low resolution, Landsat imagery is more interesting data for water detection and management of earth surface water. Landsat8 OLI/TIRS is the newest version of Landsat satellite series. In this paper, we investigated the full spectral potential of Landsat8 for water detection. It is developed many kinds of methods for this purpose that index based methods have some advantages than other methods. Pervious indices just use a limited number of spectral band. In this paper, Modified Optimization Water Index (MOWI) defined by consideration of a linear combination of bands that each coefficient of bands calculated by particle swarm algorithm. The result shows that modified optimization water index (MOWI) has a proper performance on different condition like cloud, cloud shadow and mountain shadow.
23
Liu, Changjiang, Fei Zhang, Xiangyu Ge, Xianlong Zhang, Ngai weng Chan, and Yaxiao Qi. "Measurement of Total Nitrogen Concentration in Surface Water Using Hyperspectral Band Observation Method." Water 12, no. 7 (June 27, 2020): 1842. http://dx.doi.org/10.3390/w12071842.
Full textAbstract:
Nitrogen overload is one of the main reasons for the deterioration of surface water quality. Hence, monitoring nitrogen loadings is vital in maintaining good surface water quality. Increasingly, the use of spectral reflectance to monitor nitrogen concentration in water has shown potentials, but it poses some problems. Therefore, it is necessary to explore new methods of quantitative monitoring of nitrogen concentration in surface water. In this paper, hyperspectral data from surface water in the Ebinur Lake watershed are used to select sensitive bands using spectral transformation, the spectral index, and a coupling of these two methods. The particle swarm optimization support vector machine (PSO-SVM) model, constructed on the basis of sensitive bands, is used quantitatively to estimate the total nitrogen concentration in surface water and subsequently to verify its accuracy. The results show that the bands near 680, 850, and 940 nm can be used as sensitive bands for estimation of the total nitrogen concentration of surface water in arid regions. Compared with the best estimation models constructed by sensitive bands selected using the spectral transformation or the spectral index alone, the best model based on the coupling of these two measures is more accurate (R2 = 0.604, Root Mean Square Error (RMSE) = 1.61 mg/L, Residual Prediction Deviation (RPD) = 2.002). This coupling method leads to a robust, accurate, and strong predictability model, and can contribute to improved quantitative estimation of water quality indexes of rivers in arid regions.
24
Purwanto, Anang Dwi, and Kuncoro Teguh Setiawan. "DETEKSI AWAL HABITAT PERAIRAN LAUT DANGKAL MENGGUNAKAN TEKNIK OPTIMUM INDEX FACTOR PADA CITRA SPOT 7 DAN LANDSAT 8." JURNAL ENGGANO 4, no. 2 (September 30, 2019): 174–92. http://dx.doi.org/10.31186/jenggano.4.2.174-192.
Full textAbstract:
Informasi keberadaan habitat perairan laut dangkal semakin dibutuhkan terutama dalam kegiatan pelestarian lingkungan dan monitoring di wilayah pesisir. Komponen penyusun ekosistem habitat dasar perairan laut dangkal di antaranya terumbu karang dan lamun dimana lokasi keberadaan obyek habitat ini cenderung berdekatan. Dalam interpretasi ekosistem habitat dasar perairan laut dangkal terkendala oleh lokasi keberadaan ekosistem yang berasosiasi dengan obyek lainnya. Tujuan penelitian ini adalah menentukan kombinasi komposit kanal terbaik dalam mengidentifikasi obyek habitat dasar perairan laut dangkal di Pantai Pemuteran, Bali. Data citra satelit yang digunakan dalam penelitian ini adalah citra SPOT 7 akuisisi tanggal 11 April 2018 dan citra Landsat 8 akuisisi tanggal 14 April 2018, sedangkan data terkait informasi sebaran habitat dasar perairan laut dangkal diperoleh berdasarkan hasil survei lapangan yang telah dilakukan pada tanggal 7-13 April 2018 di Pantai Pemuteran, Bali. Data citra satelit diperoleh dari Pusat Teknologi dan Data LAPAN. Untuk menentukan kombinasi dari 3 (tiga) kanal terbaik dalam interpretasi habitat dasar perairan laut dangkal digunakan metode Optimum Index Factor (OIF) dimana metode ini menggunakan nilai standar deviasi dan koefisien korelasi dari kombinasi 3 (tiga) kanal citra yang digunakan. Hasil penelitian menunjukkan kombinasi komposit 2 (hijau), 3 (merah) dan 4 (NIR) mempunyai nilai OIF tertinggi untuk citra SPOT 7, sedangkan kombinasi komposit 2 (biru), 4 (merah) dan 6 (SWIR 1) Mempunyai nilai OIF tertinggi untuk citra Landsat 8. Interpretasi sebaran habitat dasar perairan laut dangkal dapat dilakukan secara efektif dengan menggunakan citra komposit RGB 423 untuk citra SPOT 7 dan RGB 642 untuk citra Landsat 8.DETECTION OF SHALLOW WATER HABITATS USING OPTIMUM INDEX FACTORS TECHNIQUE ON SPOT 7 AND LANDSAT 8 IMAGERY. Information of the existence of the shallow water habitat is required especially in environmental conservation and monitoring of activities in coastal areas. The component of the shallow water habitat including coral reefs and seagrass where the location of the existence of these relatively close together. Interpretation of the shallow water habitat is constrained by the location of ecosystem associated with other objects. The aim of study is to determine the best combination of band composites in identifying the shallow water habitat in Pemuteran Beach, Bali. The study used SPOT 7 imagery (acquisition on April 11, 2018) and Landsat 8 imagery (acquisition on April 14, 2018). The data of the shallow water habitat based on the result of field survey was conducted on 7-13 April 2018 at Pemuteran Beach, Bali. Image data obtained from Remote Sensing Technology and Data Center of LAPAN. Determination of combination of 3 (three) bands the shallow water habitat using Optimum Index Factor (OIF) method where this method used standard deviation value and correlation coefficient from combination of 3 (three) bands. The results show the composite combinations of band 2 (green), band 3 (red) and band 4 (NIR) have the highest OIF values for SPOT 7 image, while the composite combinations of band 2 (blue), band 4 (red) and band 6 (SWIR 1) have the highest OIF values for Landsat 8 image. Interpretation of distribution of shallow water habitat can be done effectively using RGB 423 composite image (SPOT 7) and RGB 642 composite image (Landsat 8).
25
Ma, Jiang, Shou Xian Zhu, Wen Hua Zeng, and Wen Jing Zhang. "Water Depth Extraction in Minjiang Estuary Using Remotely Sensed TM Data." Advanced Materials Research 816-817 (September 2013): 602–5. http://dx.doi.org/10.4028/www.scientific.net/amr.816-817.602.
Full textAbstract:
Remote sensing provides explicit images covering Earth surface. Thus, remote sensing can be applied in water depth extraction. In this paper Minjiang Estuary has been chosen to be the study area for spectral analysis of correlation index between TM image and the water depth in charts. The result shows that in the whole single spectra TM3 provides the largest absolute correlation index and in other band ratios TM1/TM3 offers the larger absolute correlation index. Then TM3 and TM1/TM3 are applied in some models using linear, logarithmic, power exponential and exponential equations in pursuit of obtaining water depth inversion. Among these models, exponential model using TM3 is certified to be the best one.
26
Vepraskas, Claudia. "Beat the Heat: Managing Heat And Hydration In Marching Band." Journal of School Nursing 18, no. 4 (August 2002): 237–43. http://dx.doi.org/10.1177/10598405020180042001.
Full textAbstract:
Marching band students are athletes who practice outdoors under conditions that expose them to dehydration, heat exhaustion, and sunstroke. They suffer these heat-related injuries because breaking formation frequently to adequately hydrate is impractical. This project developed educational materials alerting the students and the director to heat-related illnesses and tested a simple method of fluid replacement that could be used during practice. A Heat Index chart was adapted to identify hazardous conditions; fluid intake recommendations were made based on the Heat Index. Students purchased a water bottle housed in an insulated belt that was worn during all outdoor rehearsals. Because water was readily available, the students were able to drink the necessary fluids without interrupting the rehearsal. These bottles have been used successfully for 3 years. Based on limited subjective data, the students reported feeling better, their mental acuity improved, and rehearsals were more productive. This article examines the effects of heat on the body and reports on a practical solution that has been found to protect marching band members from heat-related stress.
27
Vepraskas, Claudia. "Beat the Heat: Managing Heat And Hydration In Marching Band." Journal of School Nursing 18, no. 4 (August 2002): 237–43. http://dx.doi.org/10.1177/10598405020180042101.
Full textAbstract:
Marching band students are athletes who practice outdoors under conditions that expose them to dehydration, heat exhaustion, and sunstroke. They suffer these heat-related injuries because breaking formation frequently to adequately hydrate is impractical. This project developed educational materials alerting the students and the director to heat-related illnesses and tested a simple method of fluid replacement that could be used during practice. A Heat Index chart was adapted to identify hazardous conditions; fluid intake recommendations were made based on the Heat Index. Students purchased a water bottle housed in an insulated belt that was worn during all outdoor rehearsals. Because water was readily available, the students were able to drink the necessary fluids without interrupting the rehearsal. These bottles have been used successfully for 3 years. Based on limited subjective data, the students reported feeling better, their mental acuity improved, and rehearsals were more productive. This article examines the effects of heat on the body and reports on a practical solution that has been found to protect marching band members from heat-related stress.
28
Sawicka, Marta, and Jacek Soroka. "Application of the calibration surfaces method in quantitative analysis of water — ethanol — methanol mixture." Open Chemistry 11, no. 7 (July 1, 2013): 1239–47. http://dx.doi.org/10.2478/s11532-013-0252-1.
Full textAbstract:
AbstractThe simple and quick calibration surfaces method has been applied to the quantitative analysis of water — ethanol — methanol mixtures. The refractive index, viscosity, boiling point, density, and position of the absorption band of the solvatochromic dye and the absorbance of the band corresponding to a particular wavelength were used as measured magnitudes which are functionally related to the quantitative composition of the mixture. The 3rd order surface equation was fitted to the experimental data via the multidimensional regression method. Various pairs of macroscopic features were tested to obtain the best results. To find the solution, the set of three equations were calculated, in which two equations were the mathematical description of particular macroscopic features; the third one resulted from the definition of mass fraction. The detection and determination limits as well as the error of the method were determined which proved that the refractive index and the density were the most adequate pair of macroscopic features.
29
Xiao, Xiao, Biyu Song, Xiongfei Wen, Dengzhong Zhao, Xuejun Cheng, Chengfang Hu, Jian Xu, and Zhaohui Wang. "VIP-BP model for retrieving chlorophyll a concentration in the river by using remote sensing data." Water Quality Research Journal 52, no. 2 (May 24, 2015): 136–50. http://dx.doi.org/10.2166/wqrj.2017.055.
Full textAbstract:
Chlorophyll a (Chla) is an important indicator of phytoplankton biomass in waters, and its concentration can reflect the degree of eutrophication. This paper is aimed to develop a highly accurate and universally applicable retrieval model for the concentration of Chla in rivers using remote sensing data. Taking the middle and lower reaches of the Han River as the study area, the Chla retrieval model (VIP-BP model) is established by combining the Variable Importance Projection Index and BP neural algorithm and then calibrated by the measured data from 2012 to 2013. This model uses the VIP index for selection of the appropriate spectrum transformation form and input bands. Then, the BP neural network algorithm is integrated to estimate Chla concentration. After validation and comparison with the three-band model, the results suggest that the VIP-BP model could more accurately and really reflect the changes in Chla concentration than the three-band model in the study area. When Chla concentration decreases, the retrieval error of both models increases, while the error of the VIP-BP model is significantly lower than that of the three-band model, which indicates that the VIP-BP model is more stable and preferred.
30
Zarco-Tejada, P. J., V. González-Dugo, L. E. Williams, L. Suárez, J. A. J. Berni, D. Goldhamer, and E. Fereres. "A PRI-based water stress index combining structural and chlorophyll effects: Assessment using diurnal narrow-band airborne imagery and the CWSI thermal index." Remote Sensing of Environment 138 (November 2013): 38–50. http://dx.doi.org/10.1016/j.rse.2013.07.024.
Full text
31
Ayari, Emna, Zeineb Kassouk, Zohra Lili-Chabaane, Nicolas Baghdadi, Safa Bousbih, and Mehrez Zribi. "Cereal Crops Soil Parameters Retrieval Using L-Band ALOS-2 and C-Band Sentinel-1 Sensors." Remote Sensing 13, no. 7 (April 4, 2021): 1393. http://dx.doi.org/10.3390/rs13071393.
Full textAbstract:
This paper discusses the potential of L-band Advanced Land Observing Satellite-2 (ALOS-2) and C-band Sentinel-1 radar data for retrieving soil parameters over cereal fields. For this purpose, multi-incidence, multi-polarization and dual-frequency satellite data were acquired simultaneously with in situ measurements collected over a semiarid area, the Merguellil Plain (central Tunisia). The L- and C-band signal sensitivity to soil roughness, moisture and vegetation was investigated. High correlation coefficients were observed between the radar signals and soil roughness values for all processed multi-configurations of ALOS-2 and Sentinel-1 data. The sensitivity of SAR (Synthetic Aperture Radar) data to soil moisture was investigated for three classes of the normalized difference vegetation index (NDVI) (low vegetation cover, medium cover and dense cover), illustrating a decreasing sensitivity with increasing NDVI values. The highest sensitivity to soil moisture under the dense cover class is observed in L-band data. For various vegetation properties (leaf area index (LAI), height of vegetation cover (H) and vegetation water content (VWC)), a strong correlation is observed with the ALOS-2 radar signals (in HH(Horizontal-Horizontal) and HV(Horizontal-Vertical) polarizations). Different empirical models that link radar signals (in the L- and C-bands) to soil moisture and roughness parameters, as well as the semi-empirical Dubois modified model (Dubois-B) and the modified integral equation model (IEM-B), over bare soils are proposed for all polarizations. The results reveal that IEM-B performed a better accuracy comparing to Dubois-B. This analysis is also proposed for covered surfaces using different options provided by the water cloud model (WCM) (with and without the soil–vegetation interaction scattering term) coupled with the best accuracy bare soil backscattering models: IEM-B for co-polarization and empirical models for the entire dataset. Based on the validated backscattering models, different options of coupled models are tested for soil moisture inversion. The integration of a soil–vegetation interaction component in the WCM illustrates a considerable contribution to soil moisture precision in the HV polarization mode in the L-band frequency and a neglected effect on C-band data inversion.
32
Bai, Jueying, Qian Cui, Deqing Chen, Haiwei Yu, Xudong Mao, Lingkui Meng, and Yang Cai. "Assessment of the SMAP-Derived Soil Water Deficit Index (SWDI-SMAP) as an Agricultural Drought Index in China." Remote Sensing 10, no. 8 (August 18, 2018): 1302. http://dx.doi.org/10.3390/rs10081302.
Full textAbstract:
China is frequently subjected to local and regional drought disasters, and thus, drought monitoring is vital. Drought assessments based on available surface soil moisture (SM) can account for soil water deficit directly. Microwave remote sensing techniques enable the estimation of global SM with a high temporal resolution. At present, the evaluation of Soil Moisture Active Passive (SMAP) SM products is inadequate, and L-band microwave data have not been applied to agricultural drought monitoring throughout China. In this study, first, we provide a pivotal evaluation of the SMAP L3 radiometer-derived SM product using in situ observation data throughout China, to assist in subsequent drought assessment, and then the SMAP-Derived Soil Water Deficit Index (SWDI-SMAP) is compared with the atmospheric water deficit (AWD) and vegetation health index (VHI). It is found that the SMAP can obtain SM with relatively high accuracy and the SWDI-SMAP has a good overall performance on drought monitoring. Relatively good performance of SWDI-SMAP is shown, except in some mountain regions; the SWDI-SMAP generally performs better in the north than in the south for less dry bias, although better performance of SMAP SM based on the R is shown in the south than in the north; differences between the SWDI-SMAP and VHI are mainly shown in areas without vegetation or those containing drought-resistant plants. In summary, the SWDI-SMAP shows great application potential in drought monitoring.
33
Ettehadi Osgouei, Paria, Sinasi Kaya, Elif Sertel, and Ugur Alganci. "Separating Built-Up Areas from Bare Land in Mediterranean Cities Using Sentinel-2A Imagery." Remote Sensing 11, no. 3 (February 10, 2019): 345. http://dx.doi.org/10.3390/rs11030345.
Full textAbstract:
In this research work, a multi-index-based support vector machine (SVM) classification approach has been proposed to determine the complex and morphologically heterogeneous land cover/use (LCU) patterns of cities, with a special focus on separating bare lands and built-up regions, using Istanbul, Turkey as the main study region, and Ankara and Konya (in Turkey) as the independent test regions. The multi-index approach was constructed using three-band combinations of spectral indices, where each index represents one of the three major land cover categories, green areas, water bodies, and built-up regions. Additionally, a shortwave infrared-based index, the Normalized Difference Tillage Index (NDTI), was proposed as an alternative to existing built-up indices. All possible index combinations and the original ten-band Sentinel-2A image were classified with the SVM algorithm, to map seven LCU classes, and an accuracy assessment was performed to determine the multi-index combination that provided the highest performance. The SVM classification results revealed that the multi-index combination of the normalized difference tillage index (NDTI), the red-edge-based normalized vegetation index (NDVIre), and the modified normalized difference water index (MNDWI) improved the mapping accuracy of the heterogeneous urban areas and provided an effective separation of bare land from built-up areas. This combination showed an outstanding overall performance with a 93% accuracy and a 0.91 kappa value for all LCU classes. The results of the test regions provided similar findings and the same index combination clearly outperformed the other approaches, with 92% accuracy and a 0.90 kappa value for Ankara, and an 84% accuracy and a 0.79 kappa value for Konya. The multi-index combination of the normalized difference built-up index (NDBI), the NDVIre, and the MNDWI, ranked second in the assessment, with similar accuracies to that of the ten-band image classification.
34
Ashurov, Matin, Vladimir Gorelik, Kirill Napolskii, and Sergey Klimonsky. "Anodic Alumina Photonic Crystals as Refractive Index Sensors for Controlling the Composition of Liquid Mixtures." Photonic Sensors 10, no. 2 (October 23, 2019): 147–54. http://dx.doi.org/10.1007/s13320-019-0569-2.
Full textAbstract:
Abstract Photonic crystals based on anodic aluminum oxide films are examined as refractive index sensors for controlling the composition of water-alcohol liquid mixtures. The position of the reflectance maximum corresponding to the first photonic stop band is used as the analytical signal. Impregnation of a photonic crystal with water-ethanol and water-glycerol mixtures results in a redshift of the reflectance maximum. A fairly high refractive index sensitivity, sufficient to determine the composition of water-ethanol and water-glycerol mixtures with an accuracy of about 1 wt.%, is observed. The detailed dependencies of the analytical signal on the composition of mixtures are experimentally investigated and compared with numerical calculations. Prospects and limitations of the refractive index sensors based on anodic alumina photonic crystals are discussed.
35
Sancho-Knapik, Domingo, Javier Gismero, Alberto Asensio, José Javier Peguero-Pina, Victoria Fernández, Tomás Gómez Álvarez-Arenas, and Eustaquio Gil-Pelegrín. "Microwave l-band (1730MHz) accurately estimates the relative water content in poplar leaves. A comparison with a near infrared water index (R1300/R1450)." Agricultural and Forest Meteorology 151, no. 7 (July 2011): 827–32. http://dx.doi.org/10.1016/j.agrformet.2011.01.016.
Full text
36
Cheng, Jie, Yi Ma, and Jingyu Zhang. "Water-depth-zoning inversion based on the relationship between two-band radiance data and the depth-invariant index." Regional Studies in Marine Science 44 (May 2021): 101790. http://dx.doi.org/10.1016/j.rsma.2021.101790.
Full text
37
Muttitanon, W. "Coastal Sediment Monitoring by Spectral Analysis." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-8 (November 28, 2014): 1055–57. http://dx.doi.org/10.5194/isprsarchives-xl-8-1055-2014.
Full textAbstract:
Water monitoring is important to environment control and ecosystem studies which not only scientifically relevant but also legally binding in several countries. Suspended sediment concentration is one of the main parameters for the water monitoring and can be roughly detected from satellite. In the present study, the Chao Phraya River mouth was used as a case study to assess the suspended measuring using water quality index with Landsat TM imagery. A turbidity map was obtain by applying band math and convert to turbidity backscattering. This solution can be used for water quality index and applying with all satellite data.
38
Artigas, Francisco, Alex Marti, Norman Yao, and Ildiko Pechmann. "Chlorophyll Detection and Mapping of Shallow Water Impoundments Using Image Spectrometry." Research Letters in Ecology 2008 (2008): 1–4. http://dx.doi.org/10.1155/2008/146217.
Full textAbstract:
There exists a common perception that chlorophyll a concentrations in tidal coastal waters are unsuitable to be captured by remote sensing techniques because of high water turbidity. In this study, we use band index measurements to separate active chlorophyll pigments from other constituents in the water. Published single- and multiband spectral indices are used to establish a relationship between algal chlorophyll concentration and reflectance data. We find an index which is suitable to map chlorophyll gradients in the impoundments, ditches, and associated waterways of the Hackensack Meadowlands (NJ, USA). The resulting images clearly depict the spatial distribution of plant pigments and their relationship with the biological conditions of the waters in the estuary. Since these biological conditions are often determined by land usage, the methods in this paper provide a simple tool to address water quality management issues in fragmented urban estuaries.
39
Du, Yun, Yihang Zhang, Feng Ling, Qunming Wang, Wenbo Li, and Xiaodong Li. "Water Bodies’ Mapping from Sentinel-2 Imagery with Modified Normalized Difference Water Index at 10-m Spatial Resolution Produced by Sharpening the SWIR Band." Remote Sensing 8, no. 4 (April 22, 2016): 354. http://dx.doi.org/10.3390/rs8040354.
Full text
40
Alicandro, Maria, Valerio Baiocchi, Raffaella Brigante, and Fabio Radicioni. "Automatic Shoreline Detection from Eight-Band VHR Satellite Imagery." Journal of Marine Science and Engineering 7, no. 12 (December 13, 2019): 459. http://dx.doi.org/10.3390/jmse7120459.
Full textAbstract:
Coastal erosion, which is naturally present in many areas of the world, can be significantly increased by factors such as the reduced transport of sediments as a result of hydraulic works carried out to minimize flooding. Erosion has a significant impact on both marine ecosystems and human activities; for this reason, several international projects have been developed to study monitoring techniques and propose operational methodologies. The increasing number of available high-resolution satellite platforms (i.e., Copernicus Sentinel) and algorithms to treat them allows the study of original approaches for the monitoring of the land in general and for the study of the coastline in particular. The present project aims to define a methodology for identifying the instantaneous shoreline, through images acquired from the WorldView 2 satellite, on eight spectral bands, with a geometric resolution of 0.5 m for the panchromatic image and 1.8 m for the multispectral one. A pixel-based classification methodology is used to identify the various types of land cover and to make combinations between the eight available bands. The experiments were carried out on a coastal area with contrasting morphologies. The eight bands in which the images are taken produce good results both in the classification process and in the combination of the bands, through the algorithms of normalized difference vegetation index (NDVI), normalized difference water index (NDWI), spectral angle mapper (SAM), and matched filtering (MF), with regard to the identification of the various soil coverings and, in particular, the separation line between dry and wet sand. In addition, the real applicability of an algorithm that extracts bathymetry in shallow water using the “coastal blue” band was tested. These data refer to the instantaneous shoreline and could be corrected in the future with morphological and tidal data of the coastal areas under study.
41
Cillero Castro, Carmen, Jose Antonio Domínguez Gómez, Jordi Delgado Martín, Boris Alejandro Hinojo Sánchez, Jose Luis Cereijo Arango, Federico Andrés Cheda Tuya, and Ramon Díaz-Varela. "An UAV and Satellite Multispectral Data Approach to Monitor Water Quality in Small Reservoirs." Remote Sensing 12, no. 9 (May 9, 2020): 1514. http://dx.doi.org/10.3390/rs12091514.
Full textAbstract:
A multi-sensor and multi-scale monitoring tool for the spatially explicit and periodic monitoring of eutrophication in a small drinking water reservoir is presented. The tool was built with freely available satellite and in situ data combined with Unmanned Aerial Vehicle (UAV)-based technology. The goal is to evaluate the performance of a multi-platform approach for the trophic state monitoring with images obtained with MultiSpectral Sensors on board satellites Sentinel 2 (S2A and S2B), Landsat 8 (L8) and UAV. We assessed the performance of three different sensors (MultiSpectral Instrument (MSI), Operational Land Imager (OLI) and Rededge Micasense) for retrieving the pigment chlorophyll-a (chl-a), as a quantitative descriptor of phytoplankton biomass and trophic level. The study was conducted in a waterbody affected by cyanobacterial blooms, one of the most important eutrophication-derived risks for human health. Different empirical models and band indices were evaluated. Spectral band combinations using red and near-infrared (NIR) bands were the most suitable for retrieving chl-a concentration (especially 2 band algorithm (2BDA), the Surface Algal Bloom Index (SABI) and 3 band algorithm (3BDA)) even though blue and green bands were useful to classify UAV images into two chl-a ranges. The results show a moderately good agreement among the three sensors at different spatial resolutions (10 m., 30 m. and 8 cm.), indicating a high potential for the development of a multi-platform and multi-sensor approach for the eutrophication monitoring of small reservoirs.
42
Van Nguyen, Manh, Chao-Hung Lin, Hone-Jay Chu, Lalu Muhamad Jaelani, and Muhammad Aldila Syariz. "Spectral Feature Selection Optimization for Water Quality Estimation." International Journal of Environmental Research and Public Health 17, no. 1 (December 30, 2019): 272. http://dx.doi.org/10.3390/ijerph17010272.
Full textAbstract:
The spatial heterogeneity and nonlinearity exhibited by bio-optical relationships in turbid inland waters complicate the retrieval of chlorophyll-a (Chl-a) concentration from multispectral satellite images. Most studies achieved satisfactory Chl-a estimation and focused solely on the spectral regions from near-infrared (NIR) to red spectral bands. However, the optical complexity of turbid waters may vary with locations and seasons, which renders the selection of spectral bands challenging. Accordingly, this study proposes an optimization process utilizing available spectral models to achieve optimal Chl-a retrieval. The method begins with the generation of a set of feature candidates, followed by candidate selection and optimization. Each candidate links to a Chl-a estimation model, including two-band, three-band, and normalized different chlorophyll index models. Moreover, a set of selected candidates using available spectral bands implies an optimal composition of estimation models, which results in an optimal Chl-a estimation. Remote sensing images and in situ Chl-a measurements in Lake Kasumigaura, Japan, are analyzed quantitatively and qualitatively to evaluate the proposed method. Results indicate that the model outperforms related Chl-a estimation models. The root-mean-squared errors of the Chl-a concentration obtained by the resulting model (OptiM-3) improve from 11.95 mg · m − 3 to 6.37 mg · m − 3 , and the Pearson’s correlation coefficients between the predicted and in situ Chl- a improve from 0.56 to 0.89.
43
Rezaei-Latifi, Ali. "Modeling of the complex refractive index and reflectivity of flat surface water over the Persian Gulf at C-band." Modeling Earth Systems and Environment 6, no. 3 (May 10, 2020): 1877–85. http://dx.doi.org/10.1007/s40808-020-00797-8.
Full text
44
Rasteniene, Loreta, Stasys Pajeda, and Rimas Vaisnoras. "Self-Assembly of a Synthetic Opal Infiltrated with Liquid Crystal Like Photonic Crystal." Solid State Phenomena 97-98 (April 2004): 245–50. http://dx.doi.org/10.4028/www.scientific.net/ssp.97-98.245.
Full textAbstract:
We have studied transmission and linear dichroism spectra of synthetic opal, refractive index n-= 1.342, infiltrated with nematic liquid crystal with averaged refractive index n = 1.596 or with water n = 1.30 and alcohol n = 1.28. We demonstrating that the position of the stop band in the visible spectra is shifted by changing infiltrated material, or temperature, or by variation angle of light incidence. Multiple diffraction are discussed.
45
Lin, Yi, Zhanglin Ye, Yugan Zhang, and Jie Yu. "SPECTRAL FEATURE ANALYSIS FOR QUANTITATIVE ESTIMATION OF CYANOBACTERIA CHLOROPHYLL-A." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (June 20, 2016): 91–98. http://dx.doi.org/10.5194/isprs-archives-xli-b7-91-2016.
Full textAbstract:
In recent years, lake eutrophication caused a large of Cyanobacteria bloom which not only brought serious ecological disaster but also restricted the sustainable development of regional economy in our country. <i>Chlorophyll-a</i> is a very important environmental factor to monitor water quality, especially for lake eutrophication. Remote sensed technique has been widely utilized in estimating the concentration of <i>chlorophyll-a</i> by different kind of vegetation indices and monitoring its distribution in lakes, rivers or along coastline. For each vegetation index, its quantitative estimation accuracy for different satellite data might change since there might be a discrepancy of spectral resolution and channel center between different satellites. The purpose this paper is to analyze the spectral feature of <i>chlorophyll-a</i> with hyperspectral data (totally 651 bands) and use the result to choose the optimal band combination for different satellites. The analysis method developed here in this study could be useful to recognize and monitor cyanobacteria bloom automatically and accrately. <br><br> In our experiment, the reflectance (from 350nm to 1000nm) of wild cyanobacteria in different consistency (from 0 to 1362.11ug/L) and the corresponding <i>chlorophyll-a</i> concentration were measured simultaneously. Two kinds of hyperspectral vegetation indices were applied in this study: simple ratio (SR) and narrow band normalized difference vegetation index (NDVI), both of which consists of any two bands in the entire 651 narrow bands. Then multivariate statistical analysis was used to construct the linear, power and exponential models. After analyzing the correlation between <i>chlorophyll-a</i> and single band reflectance, SR, NDVI respetively, the optimal spectral index for quantitative estimation of cyanobacteria <i>chlorophyll-a</i>, as well corresponding central wavelength and band width were extracted. Results show that: Under the condition of water disturbance, SR and NDVI are both suitable for quantitative estimation of <i>chlorophyll-a</i>, and more effective than the traditional single band model; the best regression models for SR, NDVI with <i>chlorophyll-a</i> are linear and power, respectively. Under the condition without water disturbance, the single band model works the best. For the SR index, there are two optimal band combinations, which is comprised of infrared (700nm-900nm) and blue-green range (450nm-550nm), infrared and red range (600nm-650nm) respectively, with band width between 45nm to 125nm. For NDVI, the optimal band combination includes the range from 750nm to 900nm and 700nm to 750nm, with band width less than 30nm. For single band model, band center located between 733nm-935nm, and its width mustn’t exceed the interval where band center located in. <br><br> This study proved , as for SR or NDVI, the centers and widths are crucial factors for quantitative estimating <i>chlorophyll-a</i>. As for remote sensor, proper spectrum channel could not only improve the accuracy of recognizing cyanobacteria bloom, but reduce the redundancy of hyperspectral data. Those results will provide better reference for designing the suitable spectrum channel of customized sensors for cyanobacteria bloom monitoring at a low altitude. In other words, this study is also the basic research for developing the real-time remote sensing monitoring system with high time and high spatial resolution.
46
Li, Jia Chen, Ping Jie Huang, Di Bo Hou, and Guang Xin Zhang. "Estimation of Chemical Oxygen Demand by Ultraviolet Spectroscopic Profiling and Physical Parameters Using IPW-PLS Algorithm." Applied Mechanics and Materials 316-317 (April 2013): 606–9. http://dx.doi.org/10.4028/www.scientific.net/amm.316-317.606.
Full textAbstract:
In recent years, water pollution is increasing, especially organic pollution. The chemical oxygen demand (COD) is one of the most important evaluation index. Compared with the traditional chemical analysis method of COD, the method of spectrum analysis of organic pollutant concentration in water quality detection is fast, no chemical reagent and simple operation etc, and it is a kind of green testing technology. The current spectrum method of water quality analysis is usually based on single wavelength or the feature band extracted. It is lack of methods with the full spectrum scan. Based on water quality research,we choose the spectral analysis of COD as the objective. Combining the ultraviolet absorption spectrum with the conventional five physical parameters as the absorbance in the last wave band, we use the iterative predictor partial least squares algorithm to realize the rapid detection of water quality COD.
47
Szigarski, Christoph, Thomas Jagdhuber, Martin Baur, Christian Thiel, Marie Parrens, Jean-Pierre Wigneron, Maria Piles, and Dara Entekhabi. "Analysis of the Radar Vegetation Index and Potential Improvements." Remote Sensing 10, no. 11 (November 9, 2018): 1776. http://dx.doi.org/10.3390/rs10111776.
Full textAbstract:
The Radar Vegetation Index (RVI) is a well-established microwave metric of vegetation cover. The index utilizes measured linear scattering intensities from co- and cross-polarization and is normalized to ideally range from 0 to 1, increasing with vegetation cover. At long wavelengths (L-band) microwave scattering does not only contain information coming from vegetation scattering, but also from soil scattering (moisture & roughness) and therefore the standard formulation of RVI needs to be revised. Using global level SMAP L-band radar data, we illustrate that RVI runs up to 1.2, due to the pre-factor in the standard formulation not being adjusted to the scattering mechanisms at these low frequencies. Improvements on the RVI are subsequently proposed to obtain a normalized value range, to remove soil scattering influences as well as to mask out regions with dominant soil scattering at L-band (sparse or no vegetation cover). Two purely vegetation-based RVIs (called RVII and RVIII), are obtained by subtracting a forward modeled, attenuated soil scattering contribution from the measured backscattering intensities. Active and passive microwave information is used jointly to obtain the scattering contribution of the soil, using a physics-based multi-sensor approach; simulations from a particle model for polarimetric vegetation backscattering are utilized to calculate vegetation-based RVI-values without any soil scattering contribution. Results show that, due to the pre-factor in the standard formulation of RVI the index runs up to 1.2, atypical for an index normally ranging between zero and one. Correlation analysis between the improved radar vegetation indices (standard RVI and the indices with potential improvements RVII and RVIII) are used to evaluate the degree of independence of the indices from surface roughness and soil moisture contributions. The improved indices RVII and RVIII show reduced dependence on soil roughness and soil moisture. All RVI-indices examined indicate a coupled correlation to vegetation water content (plant moisture) as well as leaf area index (plant structure) and no single dependency, as often assumed. These results might improve the use of polarimetric radar signatures for mapping global vegetation.
48
An, G. Q. "STUDY ON REMOTE SENSING IMAGE CHARACTERISTICS OF ECOLOGICAL LAND: CASE STUDY OF ORIGINAL ECOLOGICAL LAND IN THE YELLOW RIVER DELTA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3 (April 30, 2018): 35–38. http://dx.doi.org/10.5194/isprs-archives-xlii-3-35-2018.
Full textAbstract:
Takes the Yellow River Delta as an example, this paper studies the characteristics of remote sensing imagery with dominant ecological functional land use types, compares the advantages and disadvantages of different image in interpreting ecological land use, and uses research results to analyse the changing trend of ecological land in the study area in the past 30 years. The main methods include multi-period, different sensor images and different seasonal spectral curves, vegetation index, GIS and data analysis methods. The results show that the main ecological land in the Yellow River Delta included coastal beaches, saline-alkaline lands, and water bodies. These lands have relatively distinct spectral and texture features. The spectral features along the beach show characteristics of absorption in the green band and reflection in the red band. This feature is less affected by the acquisition year, season, and sensor type. Saline-alkali land due to the influence of some saline-alkaline-tolerant plants such as alkali tent, Tamarix and other vegetation, the spectral characteristics have a certain seasonal changes, winter and spring NDVI index is less than the summer and autumn vegetation index. The spectral characteristics of a water body generally decrease rapidly with increasing wavelength, and the reflectance in the red band increases with increasing sediment concentration. In conclusion, according to the spectral characteristics and image texture features of the ecological land in the Yellow River Delta, the accuracy of image interpretation of such ecological land can be improved.
49
Wang, Qi, Linna Chai, Shaojie Zhao, and Zhongjun Zhang. "Gravimetric Vegetation Water Content Estimation for Corn Using L-Band Bi-Angular, Dual-Polarized Brightness Temperatures and Leaf Area Index." Remote Sensing 7, no. 8 (August 17, 2015): 10543–61. http://dx.doi.org/10.3390/rs70810543.
Full text
50
Meunier, V., U. Löhnert, P. Kollias, and S. Crewell. "Biases caused by the instrument bandwidth and beam width on simulated brightness temperature measurements from scanning microwave radiometers." Atmospheric Measurement Techniques 6, no. 5 (May 7, 2013): 1171–87. http://dx.doi.org/10.5194/amt-6-1171-2013.
Full textAbstract:
Abstract. More so than the traditional fixed radiometers, the scanning radiometer requires a careful design to ensure high quality measurements. Here the impact of the radiometer characteristics (e.g., antenna beam width and receiver bandwidth) and atmospheric propagation (e.g. curvature of the Earth and vertical gradient of refractive index) on scanning radiometer measurements are presented. A forward radiative transfer model that includes all these effects to represent the instrument measurements is used to estimate the biases. These biases are estimated using differences between the measurement with and without these characteristics for three commonly used frequency bands: K, V and W-band. The receiver channel bandwidth errors are less important in K-band and W-band. Thus, the use of a wider bandwidth to improve detection at low signal-to-noise conditions is acceptable at these frequencies. The biases caused by omitting the antenna beam width in measurement simulations are larger than those caused by omitting the receiver bandwidth, except for V-band where the bandwidth may be more important in the vicinity of absorption peaks. Using simple regression algorithms, the effects of the bandwidth and beam width biases in liquid water path, integrated water vapour, and temperature are also examined. The largest errors in liquid water path and integrated water vapour are associated with the beam width errors.