scholarly journals Multiscale Temporal Irreversibility of Streamflow and Its Stochastic Modelling

Hydrology ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 63
Author(s):  
Stelios Vavoulogiannis ◽  
Theano Iliopoulou ◽  
Panayiotis Dimitriadis ◽  
Demetris Koutsoyiannis
Keyword(s):  
Time Scales ◽  
Moving Average ◽  
Stochastic Modelling ◽  
The United States ◽  
Irreversible Processes ◽  
United States Geological Survey ◽  
Time Asymmetry ◽  
Flood Simulations ◽  
The Impact ◽  
Time’S Arrow

We investigate the impact of time’s arrow on the hourly streamflow process. Although time asymmetry, i.e., temporal irreversibility, has been previously implemented in stochastics, it has only recently attracted attention in the hydrological literature. Relevant studies have shown that the time asymmetry of the streamflow process is manifested at scales up to several days and vanishes at larger scales. The latter highlights the need to reproduce it in flood simulations of fine-scale resolution. To this aim, we develop an enhancement of a recently proposed simulation algorithm for irreversible processes, based on an asymmetric moving average (AMA) scheme that allows for the explicit preservation of time asymmetry at two or more time-scales. The method is successfully applied to a large hourly streamflow time series from the United States Geological Survey (USGS) database, with time asymmetry prominent at time scales up to four days.

scholarly journals COVID-19 pandemic control using restrictions and vaccination

2021 ◽  
Vol 19 (2) ◽  
pp. 1355-1372
Author(s):  
Vinicius Piccirillo ◽  
Keyword(s):  
Time Series ◽  
Moving Average ◽  
Real Data ◽  
The United States ◽  
Prevention Policy ◽  
Autoregressive Integrated Moving Average ◽  
Infected People ◽  
Marquardt Algorithm ◽  
The Impact ◽  
Methods Numerical

<abstract><p>This work deals with the impact of the vaccination in combination with a restriction parameter that represents non-pharmaceutical interventions measures applied to the compartmental SEIR model in order to control the COVID-19 epidemic. This restriction parameter is used as a control parameter, and the univariate autoregressive integrated moving average (ARIMA) is used to forecast the time series of vaccination of all individuals of a specific country. Having in hand the time series of the population fully vaccinated (real data + forecast), the Levenberg–Marquardt algorithm is used to fit an analytic function that models this evolution over time. Here, it is used two time series of real data that refer to a slow vaccination obtained from India and Brazil, and two faster vaccination as observed in Israel and the United States of America. Together with vaccination, two different control approaches are presented in this paper, which enable reduces the infected people successfully: namely, the feedback and nonfeedback control methods. Numerical results predict that vaccination can reduce the peaks of infections and the duration of the pandemic, however, a better result is achieved when the vaccination is combined with any restrictions or prevention policy.</p></abstract>

Significance of Ecohydraulics in Aquatic Ecosystem Protection

2013 ◽  
Vol 864-867 ◽  
pp. 2413-2417
Author(s):  
Hong Tao Wang ◽  
Jin Yong Zhao ◽  
Gai Ling Wang ◽  
Qing Hong Huangfu
Keyword(s):  
United States ◽  
Aquatic Ecosystem ◽  
Digital Simulation ◽  
Hydrodynamic Characteristic ◽  
Aquatic Organism ◽  
The United States ◽  
Impact Factors ◽  
United States Geological Survey ◽  
Main Research ◽  
The Impact

Ecohydraulics is an emerging interdisciplinary science and mainstream engineering researching on the interaction relationship between hydrodynamic characteristic and aquatic ecosystem, it integrates biology, geology, hydrology, morphology, ecology, engineering and other disciplines. Based on the collection of literature on ecohydraulics from Web of Science database, the bibliometric analysis on 563 literatures from the year 1991 to 2012 has been conducted, including publication year, author, country, institution, subject, source journal and keyword analysis. Some conclusions have been made that these literatures on ecohydraulics are growing exponentially year by year; these literature involves a lot of authors and forms three research groups which scattered in Britain, the United States and New Zealand, the result clearly shows a positive correlation between the number of published literatures and the length of the research history in this subject; the main institutions of these literature include United States Geological Survey, National Institute of Water and Atmospheric Research, Chinese Academy of Sciences, University of Lyon and University of Birmingham; and the subjects of these literature include environmental sciences & ecology, water resources, marine & freshwater biology, engineering and other subjects; more than 40% of the literature published in journals with the impact factors greater than 2.0. The main research contents are as follow: biological characteristics of aquatic organism, the impact of hydrodynamics on river habitats and aquatic organisms and, the feedback of the organism on flow. Theoretical analysis, system testing, statistical analysis and hybrid analog-digital simulation are primary research techniques and applications of the research concentrate on environmental flow requirement, habitat assessment, eco-engineering design and flow field control.

scholarly journals Land Use/Land Cover Change Impact on Hydrological Process in the Upper Baro Basin, Ethiopia

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Tewodros Getu Engida ◽  
Tewodros Assefa Nigussie ◽  
Abreham Berta Aneseyee ◽  
John Barnabas
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Agricultural Land ◽  
Swat Model ◽  
The United States ◽  
United States Geological Survey ◽  
Hydrological Process ◽  
Land Use Land Cover ◽  
Validation Period ◽  
The Impact

Understanding the hydrological process associated with Land Use/Land Cover (LU/LC) change is vital for decision-makers in improving human wellbeing. LU/LC change significantly affects the hydrology of the landscape, caused by anthropogenic activities. The scope of this study is to investigate the impact of LU/LC change on the hydrological process of Upper Baro Basin for the years 1987, 2002, and 2017. The Soil Water Assessment Tool (SWAT) model was used for the simulation of the streamflow. The required data for the SWAT model are soils obtained from the Food and Agriculture Organization; Digital Elevation Model (DEM) and LU/LC were obtained from the United States Geological Survey (USGS). The meteorological data such as Rainfall, Temperature, Sunshine, Humidity, and Wind Speeds were obtained from the Ethiopian National Meteorological Agency. Data on discharge were obtained from Ministry of Water, Irrigation and Electricity. Ecosystems are deemed vital. Landsat images were used to classify the LU/LC pattern using ERDAS Imagine 2014 software and the LU/LC were classified using the Maximum Likelihood Algorithm of Supervised Classification. The Sequential Uncertainty Fitting (SUFI-2) global sensitivity method within SWAT Calibration and Uncertainty Procedures (SWAT-CUP) was used to identify the most sensitive streamflow parameters. The calibration was carried out using observed streamflow data from 01 January 1990 to 31 December 2002 and a validation period from 01 January 2003 to 31 December 2009. LU/LC analysis shows that there was a drastic decrease of grassland by 15.64% and shrubland by 9.56% while an increase of agricultural land and settlement by 18.01% and 13.01%, respectively, for 30 years. The evaluation of the SWAT model presented that the annual surface runoff increased by 43.53 mm, groundwater flow declined by 27.58 mm, and lateral flow declined by 5.63 mm. The model results showed that the streamflow characteristics changed due to the LU/LC change during the study periods 1987–2017 such as change of flood frequency, increased peak flows, base flow, soil erosion, and annual mean discharge. Curve number, an available water capacity of the soil layer, and soil evaporation composition factor were the most sensitive parameters identified for the streamflow. Both the calibration and validation results disclosed a good agreement between measured and simulated streamflow. The performance of the model statistical test shows the coefficient of determination (R2) and Nash–Sutcliffe (NS) efficiency values 0.87 and 0.81 for calibration periods of 1990–2002 and 0.84 and 0.76 for the validation period of 2003 to 2009, respectively. Overall, LU/LC significantly affected the hydrological condition of the watershed. Therefore, different conservation strategies to maintain the stability and resilience of the ecosystem are vital.

THE IMPACT OF REAL EXCHANGE RATE VOLATILITY ON INDONESIA-US TRADE PERFORMANCE

2015 ◽  
Vol 9 (1) ◽  
pp. 79-93
Author(s):  
Septika Tri Ardiyanti
Keyword(s):  
United States ◽  
Moving Average ◽  
The United States ◽  
Conditional Heteroskedasticity ◽  
Bounds Testing ◽  
Trade Performance ◽  
Exchange Value ◽  
Distributed Lag ◽  
Ardl Bounds Testing ◽  
The Impact

Studi ini mengkaji dampak volatilitas nilai tukar riil terhadap kinerja perdagangan bilateral Indonesia-Amerika Serikat (AS), dengan menggunakan data periode Q1:1990 sampai dengan Q3:2012. Studi ini menggunakan dua pendekatan untuk mengukur volatilitas nilai tukar riil, yaitu model Autoregressive Conditional Heteroskedasticity (ARCH-1) dan metode Moving Average Standards Deviation (MASD). Untuk menguji hubungan jangka panjang antara variabel penelitian, digunakan prosedur Autoregressive Distributed Lag (ARDL) bounds testing. Hasil analisis menunjukkan bahwa volatilitas nilai tukar riil berpengaruh negatif terhadap impor Indonesia dari AS tetapi tidak mempengaruhi ekspor Indonesia ke AS. Dengan demikian, semakin volatile nilai tukar maka volume impor Indonesia dari AS semakin rendah. Jika Indonesia ingin menjaga neraca perdagangan, maka dianjurkan untuk mempertahankan kebijakan nilai tukar yang mengambang dan terkendali. This sudy examines the impact of real exchange value volatilities on bilateral trade performance between Indonesia and the United States utilizing the data period between Q1:1990 to Q3 2012. This study deploys two approach to measure real exchange values volatilities, Autoregressive Conditional Heteroskedasticity (ARCH-1) and Moving Average standard Deviation methods. To test the long terms relationship between variables, it uses Autogressive Distributed Lag (ARDL) bounds testing procedure. The result shows that real exchange values volatilities has negative influence on Indonesia’s import from the United States but does not affect the Indonesia’s export to the United States. Hence, the more volatile an exchange value leads to a decrease of Indonesia’s import volume from the United States. If Indonesia attempts to balance its trade, it needs to keep intact monetary policies afloat and controllable.

scholarly journals Normalized difference vegetation index analysis of the first part impacted with the breaking of the Fundão Dam in Mariana-MG

2020 ◽  
Vol 24 ◽  
pp. e27
Author(s):  
Renan Valério Eduvirgem ◽  
Claudemir Rodrigues Soares ◽  
Elissandro Voigt Beier
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
The United States ◽  
Local Economy ◽  
Vegetation Coverage ◽  
United States Geological Survey ◽  
Landsat 8 ◽  
Data Set ◽  
Mutual Cooperation ◽  
The Impact

This paper addresses the exploitation of mineral resources and suggests that an environmental management that meets a set of measures and mutual cooperation between public and private managers, civil society, and mining companies that exploit natural, renewable, and non-renewable resources is needed. Cooperation between managers and joint safety measures can prevent present and future accidents like the one that occurred in Mariana City in Minas Gerais State (MG). The questioning presented puts into discussion the disaster that occurred in Mariana City due to the rupture of the ore tailings dam (Fundão dam) in November 2015. With an estimated population of 60,000 inhabitants, Mariana City has a local economy directly linked to mining activities. Due to the impact caused by the rupture of the Fundão dam, both city and vegetation were destroyed, among other factors observed along the path followed by the tailings. However, what is discussed in this article with greater emphasis is the loss of vegetation in the watershed. The methodology compared the degree of vegetation coverage in the basin area through the analysis of the Normalized Difference Vegetation Index – NDVI for 2013, 2016, 2017, 2018, and 2019 in different months. Some images refer to August and other samples are from September, complementing the process through the use of Landsat 8 satellite images - OLI sensor, acquired from the United States Geological Survey (USGS) repository. 299 points were distributed in the quadrant to perform the analyses (n = 299). The level of significance was set at 5% with a 95% confidence, to ascertain and verify whether the data distribution is in an acceptable condition (dense or semi-dense vegetation cover). Regarding vegetation analysis, the Kolmogorov-Smirnov and Shapiro-Wilk tests were used. Both tests indicated a non-normal distribution for the NDVI data set, which indicates the absence of a vegetation index that was covered by the tailings, resulting in an area with large spaces without the coverage previously registered in 2013. We conclude that the vegetation suffered a drastic alteration provoked by the rupture of the Fundão dam which also led to homeless residents, negative impacts on the livelihood of the small farmers and fishermen, silting up of rivers and streams, death of several animal and plant species, and also affected the ecosystem and the local and regional biodiversity. 

scholarly journals Assessing the Impact of Urbanization on Outdoor Thermal Comfort in Selected Local Government Areas in Ogun State, Nigeria

2021 ◽  
Vol 5 (1) ◽  
pp. 120-139
Author(s):  
A. Akinbobola ◽  
T Fafure
Keyword(s):  
Local Government ◽  
Thermal Comfort ◽  
Temporal Trends ◽  
The United States ◽  
Outdoor Thermal Comfort ◽  
United States Geological Survey ◽  
Landsat 8 ◽  
Ogun State ◽  
The Impact ◽  
Comfort Indices

This study seeks to assess the land use land cover (LULC) and spatial-temporal trends of six outdoor thermal comfort indices in four Local Government Areas (LGAs) of Ogun state, Southwestern, Nigeria. Data used for this study are air temperature, relative humidity, cloud cover and wind speed which span from 1982 to 2018. These data were obtained from ERA-INTERIM archive. The 1986, 2000 and 2018 used for the analysis of the LULC were from the satellite imagery hosted by the United States Geological Survey (USGS). Landsat Thematic Mapper, Landsat 7 and Landsat 8 Operational Land Imager data of 1986, 2000 and 2018 to assess the changes that have taken place between these periods. Thermal comfort indices such as Effective Temperature (ET), Temperature Humidity Index (THI), Mean radiant temperature (MRT) and Relative Strain Index (RSI) were used. Rayman model was used for the computation of the three thermal comfort indices (MRT, PET, PMV). The results show decrease in vegetation, forest, and an increase in percentage of built-up areas between 1986–2000, and 2000–2018. A rapid increase in built-up areas in the three (Abeokuta South, Ifo, Shagamu,) of the four LGAs, while one (Ijebu East) has a slow increase in the built-up areas. The trend in the thermal comfort indices also shows that thermal discomfort had been on increase for the past 37 years and it was observed that the level of comfort has deteriorated more in the last decade compared to the previous decade especially in the built-up areas. This work suggests a framework for evaluating the relationship between the quantitative and qualitative parameters linking the microclimatic environment with subjective thermal assessment. This will contribute to the development of thermal comfort standards for outdoor urban settings. Also, the study will help urban planners in their decision making, and in heat forecast.

scholarly journals Increased Internet Searches for Insomnia as an Indicator of Global Mental Health During the COVID-19 Pandemic: Multinational Longitudinal Study

10.2196/22181 ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. e22181
Author(s):  
Yu-Hsuan Lin ◽  
Ting-Wei Chiang ◽  
Yu-Lun Lin
Keyword(s):  
Mental Health ◽  
Mental Distress ◽  
Global Mental Health ◽  
Moving Average ◽  
The United States ◽  
Autoregressive Integrated Moving Average ◽  
Internet Searches ◽  
Long Term Impact ◽  
The Impact

Background Real-time global mental health surveillance is urgently needed for tracking the long-term impact of the COVID-19 pandemic. Objective This study aimed to use Google Trends data to investigate the impact of the pandemic on global mental health by analyzing three keywords indicative of mental distress: “insomnia,” “depression,” and “suicide.” Methods We examined increases in search queries for 19 countries. Significant increases were defined as the actual daily search value (from March 20 to April 19, 2020) being higher than the 95% CIs of the forecast from the 3-month baseline via ARIMA (autoregressive integrated moving average) modeling. We examined the correlation between increases in COVID-19–related deaths and the number of days with significant increases in search volumes for insomnia, depression, and suicide across multiple nations. Results The countries with the greatest increases in searches for insomnia were Iran, Spain, the United States, and Italy; these countries exhibited a significant increase in insomnia searches on more than 10 of the 31 days observed. The number of COVID-19–related deaths was positively correlated to the number of days with an increase in searches for insomnia in the 19 countries (ρ=0.64, P=.003). By contrast, there was no significant correlation between the number of deaths and increases in searches for depression (ρ=–0.12, P=.63) or suicide (ρ=–0.07, P=.79). Conclusions Our analysis suggests that insomnia could be a part of routine mental health screening during the COVID-19 pandemic.

Detecting change in Landsat time series with BFAST in the eastern Hindu Kush region

2020 ◽  
Author(s):  
Saeed Akhtar Khan ◽  
Oliver Sass ◽  
Cyrus Samimi
Keyword(s):  
Time Series ◽  
The United States ◽  
Thematic Mapper ◽  
United States Geological Survey ◽  
Landsat 8 ◽  
Surface Reflectance ◽  
Data Archive ◽  
Landsat Data ◽  
Hindu Kush ◽  
The Impact

&lt;p&gt;Environmental change is a trigger of land use change and possibly for migration in the eastern Hindu Kush mountains. Vegetation along the river valleys has undergone alterations by the impact of geomorphological processes and flood dynamics, but little research has been carried out to detect and map these changes. This study aims to close research gaps by detecting change within Landsat time series for the eastern Hindu Kush region.&lt;/p&gt;&lt;p&gt;The study area is approximately 25000 km&amp;#178; large and located in the highlands of northern Pakistan and eastern Afghanistan. It is part of upper Indus basin and is prone to natural hazards such as floods, glacial lake outbursts and landslides.&lt;/p&gt;&lt;p&gt;The opening of the United States Geological Survey (USGS) Landsat data archive in 2008 led to the development of several satellite image-based time series methods for change detection. Among them, Breaks For Additive Seasonal and Trend (BFAST) was developed in 2010 to detect changes in both trend and seasonal components of the time series. The BFAST tool iteratively decomposes the time series into trend, seasonal and remainder components. The changes in the trend component denote abrupt and gradual changes while changes in seasonal component represent phenological changes.&amp;#160;&amp;#160;&lt;/p&gt;&lt;p&gt;In this study we use Landsat data in time series analysis to detect change by using BFAST. All available Surface reflectance derived data is accessed from the Landsat data archive of USGS (World Reference System-2, Path 151 and Row 35) for the years 1988 to 2019. Data is acquired from the corresponding scenes of Landsat 4-5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Landsat 8 Operational Land Imager (OLI). It is processed to Landsat Level-2 Surface Reflectance Product by USGS and therefore has already undergone geo-referencing, atmospheric correction and detection of clouds and shadow. Data have spatial and temporal resolutions of 30 m and 16 days respectively.&lt;/p&gt;&lt;p&gt;The BFAST approach was first tested on locations with a known history of change (e.g. floods) and then scaled up to the whole study area. The magnitude and timing of the change was detected and mapped for the study area. We expect that the findings of the research will benefit future local and regional risk studies.&lt;/p&gt;

scholarly journals Increased Internet Searches for Insomnia as an Indicator of Global Mental Health During the COVID-19 Pandemic: Multinational Longitudinal Study (Preprint)

2020 ◽  
Author(s):  
Yu-Hsuan Lin ◽  
Ting-Wei Chiang ◽  
Yu-Lun Lin
Keyword(s):  
Mental Health ◽  
Mental Distress ◽  
Global Mental Health ◽  
Moving Average ◽  
The United States ◽  
Autoregressive Integrated Moving Average ◽  
Internet Searches ◽  
Long Term Impact ◽  
The Impact

BACKGROUND Real-time global mental health surveillance is urgently needed for tracking the long-term impact of the COVID-19 pandemic. OBJECTIVE This study aimed to use Google Trends data to investigate the impact of the pandemic on global mental health by analyzing three keywords indicative of mental distress: “insomnia,” “depression,” and “suicide.” METHODS We examined increases in search queries for 19 countries. Significant increases were defined as the actual daily search value (from March 20 to April 19, 2020) being higher than the 95% CIs of the forecast from the 3-month baseline via ARIMA (autoregressive integrated moving average) modeling. We examined the correlation between increases in COVID-19–related deaths and the number of days with significant increases in search volumes for insomnia, depression, and suicide across multiple nations. RESULTS The countries with the greatest increases in searches for insomnia were Iran, Spain, the United States, and Italy; these countries exhibited a significant increase in insomnia searches on more than 10 of the 31 days observed. The number of COVID-19–related deaths was positively correlated to the number of days with an increase in searches for insomnia in the 19 countries (ρ=0.64, <i>P</i>=.003). By contrast, there was no significant correlation between the number of deaths and increases in searches for depression (ρ=–0.12, <i>P</i>=.63) or suicide (ρ=–0.07, <i>P</i>=.79). CONCLUSIONS Our analysis suggests that insomnia could be a part of routine mental health screening during the COVID-19 pandemic.

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