scholarly journals Sentinel-1&2 Multitemporal Water Surface Detection Accuracies, Evaluated at Regional and Reservoirs Level

2021 ◽  
Vol 13 (16) ◽  
pp. 3279
Author(s):  
Santiago Peña-Luque ◽  
Sylvain Ferrant ◽  
Mauricio C. R. Cordeiro ◽  
Thomas Ledauphin ◽  
Jerome Maxant ◽  
...  
Keyword(s):  
Water Surface ◽  
Large Scale ◽  
Time Windows ◽  
Absolute Error ◽  
Water Shortage ◽  
Global Scale ◽  
Radar Detection ◽  
Advantages And Disadvantages ◽  
Use Of Time ◽  
The Impact

Water stock monitoring is a major issue for society on a local and global scale. Sentinel-1&2 satellites provide frequent acquisitions to track water surface dynamics, proxy variables to enable water surface volume monitoring. How do we combine such observations along time for each sensor? What advantages and disadvantages of single-date, monthly or time-windowed estimations? In this context, we analysed the impact of merging information through different types and lengths of time-windows. Satellite observations were processed separately on optical (Sentinel-2) and radar (Sentinel-1) water detectors at 10m resolution. The analysis has been applied at two scales. First, validating with 26 large scenes (110 × 110 km) in different climatic zones in France, time-windows yielded an improvement on radar detection (F1-score improved from 0.72 to 0.8 for 30 days on average logic) while optical performances remained stable (F1-score 0.89). Second, validating reservoir area estimations with 29 instrumented reservoirs (20–1250 ha), time-windows presented in all cases an improvement on both optical and radar error for any window length (5–30 days). The mean relative absolute error in optical area detection improved from 16.9% on single measurements to 12.9% using 15 days time-windows, and from 22.15% to 15.1% in radar detection). Regarding reservoir filling rates, we identified an increased negative bias for both sensors when the reservoir is nearly full. This work helped to compare accuracies of separate optical and radar capabilities, where optical statistically outperforms radar at both local and large scale to the detriment of less frequent measurements. Furthermore, we propose a geomorphological indicator of reservoirs to predict the quality of radar area monitoring (R2 = 0.58). In conclusion, we suggest the use of time-windows on operational water mapping or reservoir monitoring systems, using 10–20 days time-windows with average logic, providing more frequent and faster information to water managers in periods of crisis (e.g., water shortage) compared to monthly estimations.

scholarly journals Measuring urban form: Overcoming terminological inconsistencies for a quantitative and comprehensive morphologic analysis of cities

2020 ◽  
pp. 239980832091044 ◽  
Author(s):  
Martin Fleischmann ◽  
Ombretta Romice ◽  
Sergio Porta
Keyword(s):  
Spatial Distribution ◽  
Quantitative Analysis ◽  
Urban Form ◽  
Large Scale ◽  
Global Scale ◽  
Urban Morphology ◽  
Systematic Classification ◽  
Social Patterns ◽  
The Impact

Unprecedented urbanisation processes characterise the Great Acceleration, urging urban researchers to make sense of data analysis in support of evidence-based and large-scale decision-making. Urban morphologists are no exception since the impact of urban form on fundamental natural and social patterns (equity, prosperity and resource consumption’s efficiency) is now fully acknowledged. However, urban morphology is still far from offering a comprehensive and reliable framework for quantitative analysis. Despite remarkable progress since its emergence in the late 1950s, the discipline still exhibits significant terminological inconsistencies with regards to the definition of the fundamental components of urban form, which prevents the establishment of objective models for measuring it. In this article, we present a study of existing methods for measuring urban form, with a focus on terminological inconsistencies, and propose a systematic and comprehensive framework to classify urban form characters, where ‘urban form character’ stands for a characteristic (or feature) of one kind of urban form that distinguishes it from another kind. In particular, we introduce the Index of Elements that allows for a univocal and non-interpretive description of urban form characters. Based on such Index of Elements, we develop a systematic classification of urban form according to six categories (dimension, shape, spatial distribution, intensity, connectivity and diversity) and three conceptual scales (small, medium, large) based on two definitions of scale (extent and grain). This framework is then applied to identify and organise the urban form characters adopted in available literature to date. The resulting classification of urban form characters reveals clear gaps in existing research, in particular, in relation to the spatial distribution and diversity characters. The proposed framework reduces the current inconsistencies of urban morphology research, paving the way to enhanced methods of urban form systematic and quantitative analysis at a global scale.

scholarly journals Predicting frequency changes of global-scale solar Rossby modes due to solar cycle changes in internal rotation

2020 ◽  
Vol 640 ◽  
pp. L10 ◽  
Author(s):  
C. R. Goddard ◽  
A. C. Birch ◽  
D. Fournier ◽  
L. Gizon
Keyword(s):  
Internal Rotation ◽  
Large Scale ◽  
Peak Frequency ◽  
Global Scale ◽  
Frequency Change ◽  
Theory Approach ◽  
Time Varying ◽  
Solar Cycles ◽  
Frequency Changes ◽  
The Impact

Context. Large-scale equatorial Rossby modes have been observed on the Sun over the last two solar cycles. Aims. We investigate the impact of the time-varying zonal flows on the frequencies of Rossby modes. Methods. A first-order perturbation theory approach is used to obtain an expression for the expected shift in the mode frequencies due to perturbations in the internal rotation rate. Results. Using the time-varying rotation from helioseismic inversions we predict the changes in Rossby mode frequencies with azimuthal orders from m = 1 to m = 15 over the last two solar cycles. The peak-to-peak frequency change is less than 1 nHz for the m = 1 mode, grows with m, and reaches 25 nHz for m = 15. Conclusions. Given the observational uncertainties on mode frequencies due to the finite mode lifetimes, we find that the predicted frequency shifts are near the limit of detectability.

Current and promising strategies to prevent and reduce aflatoxin contamination in grains and food matrices

2020 ◽  
pp. 1-12
Author(s):  
S.L. Gibellato ◽  
L.F. Dalsóquio ◽  
I.C.A. do Nascimento ◽  
T.M. Alvarez
Keyword(s):  
Secondary Metabolites ◽  
Large Scale ◽  
Industrial Sector ◽  
Global Scale ◽  
Aflatoxin Contamination ◽  
Advantages And Disadvantages ◽  
Physical Chemical ◽  
The World ◽  
Food Matrices ◽  
Culture Supernatants

Mycotoxins are secondary metabolites produced by filamentous fungi that colonise various crops around the world and cause major damage to the agro-industrial sector on a global scale. Considering the estimative of population growth in the next decades, it is of fundamental importance the implementation of practices that help prevent the economics and social impacts of aflatoxin contamination. Even though various approaches have been developed – including physical, chemical and biological approaches – there is not yet one that strikes a balance in terms of safety, food quality and cost, especially when considering large scale application. In this review, we present a compilation of advantages and disadvantages of different strategies for prevention and reduction of aflatoxin contamination. Biological approaches represent the trend in innovations mainly due to their specificity and versatility, since it is possible to consider the utilisation of whole microorganisms, culture supernatants, purified enzymes or even genetic engineering. However, challenges related to improvement of the efficiency of such methods and ensuring safety of treated foods still need to be overcome.

scholarly journals Global-scale brittle plastic rheology at the cometesimals merging of comet 67P/Churyumov–Gerasimenko

2020 ◽  
Vol 117 (19) ◽  
pp. 10181-10187
Author(s):  
Marco Franceschi ◽  
Luca Penasa ◽  
Matteo Massironi ◽  
Giampiero Naletto ◽  
Sabrina Ferrari ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Global Scale ◽  
Refractory Materials ◽  
High Porosity ◽  
A Minor ◽  
The Impact ◽  
Comet 67P ◽  
Dextral Strike Slip ◽  
Minor Extent

Observations of comet nuclei indicate that the main constituent is a mix of ice and refractory materials characterized by high porosity (70–75%) and low bulk strength (10−4–10−6 MPa); however, the nature and physical properties of these materials remain largely unknown. By combining surface inspection of comet 67P/Churyumov–Gerasimenko and three-dimensional (3D) modeling of the independent concentric sets of layers that make up the structure of its two lobes, we provide clues about the large-scale rheological behavior of the nucleus and the kinematics of the impact that originated it. Large folds in the layered structure indicate that the merging of the two cometesimals involved reciprocal motion with dextral strike–slip kinematics that bent the layers in the contact area without obliterating them. Widespread long cracks and the evidence of relevant mass loss in absence of large density variations within the comet’s body testify that large-scale deformation occurred in a brittle-plastic regime and was accommodated through folding and fracturing. Comparison of refined 3D geologic models of the lobes with triaxial ellipsoids that suitably represent the overall layers arrangement reveals characteristics that are consistent with an impact between two roughly ellipsoidal cometesimals that produced large-scale axial compression and transversal elongation. The observed features imply global transfer of impact-related shortening into transversal strain. These elements delineate a model for the global rheology of cometesimals that could be possible evoking a prominent bonding action of ice and, to a minor extent, organics.

scholarly journals River network and hydro-geomorphology parametrization for global river routing modelling at 1/12° resolution

2021 ◽  
Author(s):  
Simon Munier ◽  
Bertrand Decharme
Keyword(s):  
High Resolution ◽  
Water Resources ◽  
Spatial Resolution ◽  
Large Scale ◽  
Flow Direction ◽  
Global Scale ◽  
River Network ◽  
Added Value ◽  
The Impact ◽  
River Routing

Abstract. Global scale river routing models (RRMs) are commonly used in a variety of studies, including studies on the impact of climate change on extreme flows (floods and droughts), water resources monitoring or large scale flood forecasting. Over the last two decades, the increasing number of observational datasets, mainly from satellite missions, and the increasing computing capacities, have allowed better performances of RRMs, namely by increasing their spatial resolution. The spatial resolution of a RRM corresponds to the spatial resolution of its river network, which provides flow direction of all grid cells. River networks may be derived at various spatial resolution by upscaling high resolution hydrography data. This paper presents a new global scale river network at 1/12° derived from the MERIT-Hydro dataset. The river network is generated automatically using an adaptation of the Hierarchical Dominant River Tracing (DRT) algorithm, and its quality is assessed over the 70 largest basins of the world. Although this new river network may be used for a variety of hydrology-related studies, it is here provided with a set of hydro-geomorphological parameters at the same spatial resolution. These parameters are derived during the generation of the river network and are based on the same high resolution dataset, so that the consistency between the river network and the parameters is ensured. The set of parameters includes a description of river stretches (length, slope, width, roughness, bankfull depth), floodplains (roughness, sub-grid topography) and aquifers (transmissivity, porosity, sub-grid topography). The new river network and parameters are assessed by comparing the performances of two global scale simulations with the CTRIP model, one with the current spatial resolution (1/2°) and the other with the new spatial resolution (1/12°). It is shown that CTRIP at 1/12° overall outperforms CTRIP at 1/2°, demonstrating the added value of the spatial resolution increase. The new river network and the consistent hydro-geomorphology parameters may be useful for the scientific community, especially for hydrology and hydro-geology modelling, water resources monitoring or climate studies.

scholarly journals Assessing the Impact of Coronavirus Crisis on the Nature and Trends of Remote Employment in Ukraine

2020 ◽  
Vol 11 (514) ◽  
pp. 139-145
Author(s):  
M. R. Lychkovska ◽  
Keyword(s):  
Civil Society ◽  
Large Scale ◽  
The State ◽  
The Novel ◽  
Social Partnership ◽  
Advantages And Disadvantages ◽  
Main Factors ◽  
Business Entities ◽  
The Impact ◽  
Modern Technologies

The article is aimed at generalizing the essential content of the concept of «remote employment» in the context of components that form it, analyzing the main factors of influence on these components, determining trends and features of development and spread of remote employment in coronavirus crisis. Analyzing and summarizing the scientific works of many scholars and practitioners, the sequence of development and implementation of the novel alternative forms of employment is researched. The tendency to change their essential content is defined as being dependent on the development and introduction of modern technologies. The main factors influencing the possibility of transferring novel forms of employment into a virtual mode are analyzed. The main advantages and disadvantages of spread of remote employment in lockdown conditions are allocated and analyzed. It is specified that a significant part of them can be formulated as follows: the first ones – as an advance that needs to be shared; the second ones – as problems to be solved. Doing this is quite feasible and necessary in order to develop the appropriate policy. As a result of the research, the main obstacles to the development of remote employment are identified, which include a large-scale downturn in the economic attitudes of business entities and the growth of social tension. It is reasoned that under such conditions, the strong-willed orders on the part of government can only worsen the existing situation. It is proved that only strengthening the partnership between the State, business and civil society on the basis of restoring mutual trust of all economic actors will provide an opportunity to develop a deliberate policy of recovery, part of which is the large-scale proliferation of remote labor. Remote labor will become not only a mechanism for overcoming coronavirus crisis, but also a mechanism for large-scale renewal of Ukraine’s economy on the basis of the use of the latest technologies. Prospects for further research in this direction are the creation and adapting of novel forms of remote labor, their formalization, institutional and legal support, the construction of new models of full-fledged social partnership between the State, business and civil society in the sphere of labor and employment, etc.

scholarly journals Impact Location on a Fan-Ring Shaped High-Stiffened Panel Using Adaptive Energy Compensation Threshold Filtering Method

2019 ◽  
Vol 9 (9) ◽  
pp. 1763 ◽  
Author(s):  
Yibo Li ◽  
Zhe Wang ◽  
Xiaobo Rui ◽  
Lei Qi ◽  
Jiawei Liu ◽  
...  
Keyword(s):  
Frequency Band ◽  
Lamb Wave ◽  
Large Scale ◽  
Absolute Error ◽  
Stiffened Panel ◽  
Impact Location ◽  
Propagation Law ◽  
Energy Compensation ◽  
Error Standard Deviation ◽  
The Impact

The increase in the number of space debris is a serious threat to the safe operation of in-orbit spacecraft. The propagation law of the impact signal in the stiffened panel of the spacecraft’s sealed bulkhead is very complicated, and there is less research on the impact source location in the high-stiffened panel. In this paper, an adaptive energy compensation threshold filtering (AECTF) method based on acoustic emission is proposed, which can realize large-scale, fast and accurate locating of the impact source on the stiffened panel with less resource consumption. The influence law of the stiffeners on the lamb wave is analyzed by finite element simulation, and the Lamb wave energy factor curve is obtained. The correctness of the simulation is verified by the locating experiment on the impact point. The results show that the proposed AECTF method has better adaptability and can correctly locate the impact points in complicated locations. By selecting the appropriate frequency band to filter the signal, the locating accuracy and stability can be improved. When the frequency band is 100–200 kHz, the locating result is optimal, the average absolute error is 7.0 mm, the average relative error is 0.86%, and the error standard deviation is 3.5 mm. This study will generate fresh insight into the impact location technology of high-stiffened panel and provide a reference for the in-orbit spacecraft health monitoring system.

scholarly journals Methane as a diagnostic tracer of changes in the net circulation of the middle atmosphere

2014 ◽  
Vol 14 (17) ◽  
pp. 24183-24220
Author(s):  
E. E. Remsberg
Keyword(s):  
Time Series ◽  
Northern Hemisphere ◽  
Large Scale ◽  
Middle Atmosphere ◽  
Chemical Conversion ◽  
Global Scale ◽  
Positive Trend ◽  
Residual Circulation ◽  
Use Of Time ◽  
Extratropical Latitude

Abstract. This study makes use of time series of methane (CH4) data from the Halogen Occultation Experiment (HALOE) to determine whether there were any statistically significant changes of the net circulation within the stratosphere and lower mesosphere during 1992–2005. HALOE CH4 profiles in terms of mixing ratio vs. pressure-altitude are binned into subtropical and extratropical latitude zones of the southern and of the Northern Hemisphere, and their separate time series are then analyzed using multiple linear regression (MLR) techniques. A positive trend in the subtropics and a negative trend in the extratropics is interpreted as indicating an acceleration of the net circulation. A significant acceleration is found in the Northern Hemisphere from 20 hPa to 7 hPa, a likely indication of changes from the effects of wave activity during those years. No similar acceleration is found in the Southern Hemisphere. The trends from HALOE H2O are analyzed and compared with those from CH4 for consistency because H2O is a primary product in the upper stratosphere of the chemical conversion of CH4. The CH4 and H2O trends have a ratio of nearly 2 : 1, and they are anti-correlated most clearly near the stratopause in the southern extratropics. Seasonal anomalies are found in the HALOE CH4 time series of the lower mesosphere, and they are ascribed to wave-driven, secondary residual circulation cells associated with the descent of the SAO westerlies. The time series residuals for CH4 of the lower mesosphere also exhibit aperiodic structure, and it is anti-correlated with that of the tracer-like species HCl. Such structure indicates the effects of variations in the wave forcing. It is concluded that multi-year, global-scale distributions of CH4 are very useful for diagnosing large-scale changes of the net transport within the middle atmosphere.

scholarly journals Russian Tourism in the Era of the Covid-19 Pandemic: New Trends

Discourse ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 74-82
Author(s):  
E. A. Vostrova
Keyword(s):  
Large Scale ◽  
Rental Housing ◽  
Global Scale ◽  
Tourism Industry ◽  
Social Experiment ◽  
Short Term ◽  
The Public ◽  
Travel Planning ◽  
The Social ◽  
The Impact

Introduction. The era of the Covid-19 pandemic has had a serious impact on changes in various areas of our society, and also predetermined the transformation of the Russian tourism industry. The purpose of the work is to identify new trends in Russian tourism in the context of the Covid-19 pandemic.Methodology and sources. The study used the method of selective observation and the method of forecasting, carried out the sociological analysis of the works of modern scientists N.A. Voskolovich, I.V. Loguntsova, B.M. Eidelman, O.A. Bunakov, L.R. Fakhrutdinova, V. Durly and the large-scale study of the impact of the pandemic on the tourism industry in Russia (906 respondents).Results and discussion. The author has deepened his understanding of the process of de-globalization in relation to Russian tourism during a pandemic. The pandemic is accelerating de-globalization, the megatrend that could become strategic in tourism for the foreseeable future. This experience will contribute to the emergence and popularization of new tourism trends: the increase in the number of travel near the place of residence and within the country, the spread of digitalization, the personalization of travel offers, travel planning with safety in mind and attention to the sanitary and epidemiological situation, an increase in ecotourism and excursion tourism, an increase in the number of car trips, as well as the reorientation of some tourists from hotels to short-term rental housing.Conclusion. From a futuristic perspective, the pandemic has greatly benefited the panorama of events unfolding before our eyes. The pandemic, speaking in futuristic terms, can be classified as a “black swan”. This is the social experiment on a global scale, which determines the emergence of new tourism trends, and also forms in the eyes of the public the special attitude towards Russian tourism as a truly important industry.

scholarly journals The Impact of Global Technology on Music Industry: The End of Copyright Regime

2018 ◽  
Vol 2 (1) ◽  
pp. 29
Author(s):  
Putri Hergianasari ◽  
Atyanta Nika Rumaksari
Keyword(s):  
Negative Impact ◽  
Music Industry ◽  
Global Scale ◽  
The Internet ◽  
Advantages And Disadvantages ◽  
Starting Point ◽  
The Government ◽  
Global World ◽  
The Impact ◽  
The Eu

<p>On a global scale, the music industry is currently experiencing declining growth after a significant decline in profits. This phenomenon is common in the era of digital transformation. Based on the EU report (European Commission, 2017) that global technology is changing rapidly. This reflects the desire of humans to do more by finding opportunities to meet their needs. The internet is the starting point for why the global world is changing so fast. One example is the global economic sector. By using the internet, people can search for all digital entertainment content easily without filtering it out. Sharing files on the internet has a negative impact on the music industry's sales the old way. They demand the termination of sharing music through the internet such as Youtube. This paper analyzes the advantages and disadvantages of company-based file-sharing businesses in Indonesia. How the government takes advantage of this business and how the Indonesian music industry overcomes the effects of globalization</p>

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