Using four different approaches to separate the effects of climate change and human activities on sediment discharge in karst watersheds

2021 ◽  
Author(s):  
Cheng Si ◽  
Yu Xingxiu ◽  
Li Zhenwei ◽  
Xu Xianli ◽  
Ding Mingming
Keyword(s):  
Human Activities ◽  
Abrupt Change ◽  
Linear Regression Method ◽  
Sediment Discharge ◽  
Simple Linear Regression ◽  
Elastic Coefficient ◽  
Double Mass ◽  
Curve Method ◽  
Discharge Variation ◽  
Coefficient Method

<p>Quantifying the relative contributions of climate and human activities to changes in sediment discharge is closely related to regional water resources, soil management and even the healthy operation of ecosystems. However, few studies used different methods to decompose influences of climatic variability and human activities on sediment discharge change, especially in karst regions of southwest China where experiencing severe soil erosion. This study systematically reviewed four different methods including simple linear regression method, double mass curve method, sediment identify factor analysis, and elastic coefficient method to separate the contribution of climate change and human activities to sediment discharge variation in four karst watersheds of southwest during 1955 to 2015. The trend and abrupt change year of sediment discharge in four watersheds were obtained by nonparametric Mann-Kendall test. Result showed that the sediment discharge in four watersheds all decreased significantly (<em>P</em><0.05), and the abrupt change years were 2003, 2003, 2004 and 2004 for Wujiang, Yujiang, Hongshui, and Xijiang watersheds, respectively. The simple linear regression method, double mass curve method and elastic coefficient method all indicated that the sediment discharge was mainly influenced by human activities, with the contribution rate ranging from 73% to 101%. For the sediment identify factor analysis method, the sediment concentration is the principal factor influencing sediment discharge variation, and the contribution rate of sediment discharge varied from 100% to 154%. The results can provide good reference value for evaluating the influence of the climate and human activities on sediment discharge, and is significance for proper formulation of regional soil conservation policy in karst watersheds.</p>

scholarly journals Changes in streamflow and sediment discharge and the response to human activities in the middle reaches of the Yellow River

2011 ◽  
Vol 15 (1) ◽  
pp. 1-10 ◽  
Author(s):  
P. Gao ◽  
X.-M. Mu ◽  
F. Wang ◽  
R. Li
Keyword(s):  
Human Activities ◽  
Yellow River ◽  
Series Data ◽  
The Yellow River ◽  
Sediment Discharge ◽  
Dominant Position ◽  
Precipitation Response ◽  
Before And After ◽  
Double Mass ◽  
Discharge Variation

Abstract. The changes in streamflow and sediment discharge in the middle reaches of the Yellow River are a focus. In this paper, based on the precipitation, streamflow and sediment discharge series data (1950–2008), the streamflow and sediment discharge variation and its impact on precipitation/response to human activities have been analysis. The results show that significant decreasing trends in annual streamflow and sediment discharge have existed since the late 1950s in the middle reaches of the Yellow River (P = 0.01). Change-point analyses further revealed that transition years existed and that abrupt decline in streamflow and sediment discharge began in 1985 and 1981, respectively, in the middle reaches of the Yellow River (P = 0.05). Adoption of conservation measures in the 1980s and 1990s corroborates the identified transition years. Double-mass curves of precipitation vs. streamflow (sediment) for the periods before and after the transition year show remarkable decreases in proportionality of streamflow (sediment) generation. Compared with the period before the transition year, cumulative streamflow and cumulative sediment discharge reduced respectively by 17.8% and 28% during 1985–2008, which was caused by human intervention, in the middle reaches of the Yellow River. It is, therefore, concluded that human activities occupied a dominant position and played a major role in the streamflow and sediment discharge reduction in the middle reaches of the Yellow River.

scholarly journals Changes in streamflow and sediment discharge and the response to human activities in the middle reaches of the Yellow River

2010 ◽  
Vol 7 (5) ◽  
pp. 6793-6822 ◽  
Author(s):  
P. Gao ◽  
X.-M. Mu ◽  
F. Wang ◽  
R. Li
Keyword(s):  
Human Activities ◽  
Yellow River ◽  
The Yellow River ◽  
Human Intervention ◽  
Sediment Discharge ◽  
Annual Streamflow ◽  
Dominant Position ◽  
Before And After ◽  
Double Mass ◽  
Precipitation Changes

Abstract. The objectives of this work are: (a) to statistically test and quantify the decreasing trends of streamflow and sediment discharge in the middle reaches of the Yellow River in China during 1950–2008, (b) to identify change points or transition years of the decreasing trends, and (c) to diagnose whether the decreasing trends were caused by precipitation changes or human intervention, or both. The results show that significant decreasing trends in annual streamflow and sediment discharge have existed since the late 1950s in the middle reaches of the Yellow River (P=0.01). Change-point analyses further revealed that transition years existed and that abrupt decline in streamflow and sediment discharge began in 1985 and 1981, respectively, in the middle reaches of the Yellow River (P=0.05). Adoption of conservation measures in the 1980s and 1990s corroborates the identified transition years. Double-mass curves of precipitation vs. streamflow (sediment) for the periods before and after the transition year show remarkable decreases in proportionality of streamflow (sediment) generation. Compared with the period before the transition year, cumulative streamflow and cumulative sediment discharge reduced respectively by 17.8% and 28% during 1985–2008, which was caused by human intervention, in the middle reaches of the Yellow River. It is, therefore, concluded that human activities occupied a dominant position and played a major role in the streamflow and sediment discharge reduction in the middle reaches of the Yellow River.

scholarly journals Using the Mann–Kendall test and double mass curve method to explore stream flow changes in response to climate and human activities

2018 ◽  
Vol 10 (4) ◽  
pp. 725-742 ◽  
Author(s):  
Abdollah Pirnia ◽  
Mohammad Golshan ◽  
Hamid Darabi ◽  
Jan Adamowski ◽  
Sajad Rozbeh
Keyword(s):  
Climate Variability ◽  
Human Activities ◽  
Stream Flow ◽  
Wet Season ◽  
Runoff Changes ◽  
Double Mass ◽  
Runoff Decrease ◽  
Curve Method ◽  
Dry Seasons ◽  
Wet And Dry Seasons

AbstractAnalyzing intra-annual stream flow can reveal the main causes for runoff changes and the contributions of climate variability and human activities. For this purpose, the Mann–Kendall and cumulative rank difference (CRD) tests, and the double mass curve method, were applied to a time series of hydro-meteorological variables from 1971 to 2010 in the Tajan River basin in Iran. Results indicated that runoff changes in the wet and dry seasons after 1999 had significant respective decreasing and increasing trends, at the 0.01 confidence level, due to dam construction. In the pre-dam period (1991–1998), the results of the double mass curve method showed that climate variability and human activities contributed 57.76% and 42.24%, respectively, to the runoff decrease during the wet season. For the post-dam period (1999–2010), climate variability and anthropogenic activities contributed 24.68% and 75.32%, respectively, to the wet season runoff decrease of 116.55 mm. On the other hand, in the same period during the dry season, climate variability contributed −30.68% and human activities contributed 130.68% to the runoff increase of 41.45 mm. It is evident that runoff changes in both wet and dry seasons were mainly due to human activities associated with dam construction to meet water supply demands for agriculture.

scholarly journals Variation Analysis of Streamflows from 1956 to 2016 Along the Yellow River, China

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1231 ◽  
Author(s):  
Xiujie Wang ◽  
Bernard Engel ◽  
Ximin Yuan ◽  
Peixian Yuan
Keyword(s):  
Water Resources ◽  
Change Point ◽  
Human Activities ◽  
Abrupt Change ◽  
Yellow River ◽  
Rank Correlation ◽  
Test Method ◽  
The Yellow River ◽  
Linear Regression Method ◽  
Rank Correlation Method

With the change of climate and the impacts of human activities, the water resources crisis of the Yellow River is becoming increasingly serious. How and why did the streamflows of the Yellow River basin change? Based on observed annual runoff data (1956–2016) of 10 main hydrological stations along the Yellow River, the linear regression method, the Spearman rank correlation method and the Mann-Kendall test method are used to analyze runoff trend. The orderly clustering method, the sliding t test method and the Lee-Heghinian Method are used to identify the abrupt change point. Finally, the wavelet analysis method is used to identify runoff time series period. The results show that: (1) With the exception of the streamflow of Tangnaihai, the streamflows of all examined stations have significantly declining trends. The decrease of the streamflow from the upper to the middle to the lower reaches is becoming more and more obvious; (2) The runoff of the Yellow River has changed greatly. The abrupt change point at Tangnaihai occurred in 1989. The abrupt change points of the other stations took place in 1985; (3) The runoff along the Yellow River presents multi-time scale changes. The streamflows appear to have strongest periods of 25–40 years with a 40-year scale, which indicate the alternate oscillations of the high and the low water periods. The periods of <6 and 7–24 years are not stable and are complicated. The first main period of runoff in the Yellow River is 30 years; (4) The streamflow upstream of Tangnaihai station is mainly affected by the climate. The streamflows downstream of Tangnaihai station are influenced by human activities, especially water extraction and diversion and the operations of the large reservoirs. These research results have important practical guiding significance for hydrological forecasting, evaluation and management of water resources, construction of water conservancy projects and sustainable utilization of water resources in the region.

scholarly journals Analysis and Prediction of “AI + Education” Attention Based on Baidu Index—Taking Guizhou Province as an Example

2021 ◽  
Vol 13 (5) ◽  
pp. 120
Author(s):  
Yulin Zhao ◽  
Junke Li ◽  
Jiang-E Wang
Keyword(s):  
Artificial Intelligence ◽  
Southwest China ◽  
Arima Model ◽  
Modern Technology ◽  
Guizhou Province ◽  
Western Region ◽  
Elastic Coefficient ◽  
The Sustainable Development ◽  
Intelligence Education ◽  
Coefficient Method

Studying the attention of “artificial intelligence + education” in ethnic areas is of great significance for China for promoting the integrated development of new educational modes and modern technology in the western region. Guizhou province is an area inhabited by ethnic minorities, located in the heart of Southwest China. The development of its intelligent education has strong enlightenment for the whole country and the region. Therefore, this paper selects the Baidu Index of “artificial intelligence (AI) + education” in Guizhou province from 2013 to 2020, analyzes the spatial–temporal characteristics of its network attention by using the elastic coefficient method, and builds the ARIMA model on this basis to predict future development. The results show that the public’s attention to “AI + education” differs significantly in time and space. Then, according to the prediction results, this paper puts forward relevant suggestions for the country to promote the sustainable development of education in western ethnic areas.

scholarly journals Identification of the Impacts of Climate Changes and Human Activities on Runoff in the Jinsha River Basin, China

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaowan Liu ◽  
Dingzhi Peng ◽  
Zongxue Xu
Keyword(s):  
Water Balance ◽  
River Basin ◽  
Human Activities ◽  
Climate Changes ◽  
Balance Method ◽  
Variation Method ◽  
Rainfall Runoff ◽  
Jinsha River ◽  
Water Balance Method ◽  
Double Mass

Quantifying the impacts of climate changes and human activities on runoff has received extensive attention, especially for the regions with significant elevation difference. The contributions of climate changes and human activities to runoff were analyzed using rainfall-runoff relationship, double mass curve, slope variation, and water balance method during 1961–2010 at the Jinsha River basin, China. Results indicate that runoff at upstream and runoff at midstream are both dominated by climate changes, and the contributions of climate changes to runoff are 63%~72% and 53%~68%, respectively. At downstream, climate changes account for only 13%~18%, and runoff is mainly controlled by human activities, contributing 82%~87%. The availability and stability of results were compared and analyzed in the four methods. Results in slope variation, double mass curve, and water balance method except rainfall-runoff relationship method are of good agreement. And the rainfall-runoff relationship, double mass curve, and slope variation method are all of great stability. The four methods and availability evaluation of them could provide a reference to quantification in the contributions of climate changes and human activities to runoff at similar basins in the future.

Perancangan Aplikasi Prediksi Jumlah Pendaftar Siswa Baru Dengan Metode Regresi Linier (Studi Kasus: SMA RK Deli Murni Bandar Baru)

2020 ◽  
Vol 3 (3) ◽  
pp. 330-334
Author(s):  
Novita Ria Lase ◽  
Fristi Riandari
Keyword(s):  
Linear Regression ◽  
Regression Method ◽  
Point Of View ◽  
Computational Techniques ◽  
Linear Regression Method ◽  
Simple Linear Regression ◽  
Tuition Fees ◽  
Use Of Data ◽  
New Students ◽  
New Student

The problem of the SMA RK Deli Murni Bandar Baru school is to predict how many facilities that need to be provided for new students such as chairs, tables and others. This study discusses the prediction of the number of new student registrants at SMA RK Deli Murni Bandar Baru based on the amount of tuition fees using a simple linear regression method. From a commercial point of view, the use of data mining can be used to handle the explosion of data volumes, using computational techniques can be used to produce information needed which is an asset that can increase the competitiveness of an institution. Prediction is almost the same as classification and estimation, except that in the prediction the value of the results will be in the future. This system can be used to predict the number of applicants in the following year to help the school. The advantage is that this simple linear regression method is very simple so that it is easy to calculate and use. Saves the time needed to solve problems, especially those that are very complex.

scholarly journals Pengaruh Religiositas terhadap Keputusan Pembelian Pakaian Muslimah

2021 ◽  
Vol 4 (1) ◽  
pp. 14-24
Author(s):  
Dessy Trimulyani ◽  
Hendro Lisa ◽  
Ferdinan Ferdinan
Keyword(s):  
Linear Regression ◽  
Quantitative Research ◽  
Muslim Women ◽  
Regression Method ◽  
Linear Regression Method ◽  
Simple Linear Regression ◽  
Method Analysis

Starting from the phenomenon occurred especially among Muslim women who were very concerned with fashion issues. Many of them did not know the function of the clothes they wear, and how Islam arranges the clothes. The purpose of this study was to determine the influence of religiosity on the decision of purchasing Muslim clothes in Tembilahan District. This was quantitative research by simple linear regression method analysis. The results showed that the T count was bigger than the T table. The T table was 12,763>2,024 and sig. 0.000 <0.05 means Ha was accepted, and Ho was rejected. The contribution of religiosity to the decision toward purchasing Muslim clothing by looking at the results of the R Square was 81.1%, while the remaining 18.9% influenced by other factors outside of the researcher's discussion.

scholarly journals An approach to quality analysis, gap filling and homogeneity of monthly rainfall series

2021 ◽  
Vol 29 ◽  
pp. 157-168
Author(s):  
Janaina Cassiano dos Santos ◽  
Gustavo Bastos Lyra ◽  
Marcel Carvalho Abreu ◽  
Daniel Carlos de Menezes
Keyword(s):  
Linear Regression ◽  
Rio De Janeiro ◽  
The State ◽  
Monthly Rainfall ◽  
Rainfall Series ◽  
Quality Analysis ◽  
Linear Regression Method ◽  
Simple Linear Regression ◽  
Gap Filling ◽  
Unsupervised Approaches

The aim of this work was to propose a method for the consistency of climatic series of monthly rainfall using a supervised and unsupervised approach. The methodology was applied for the series (1961-2010) of rainfall from weather stations located in the State of Rio de Janeiro (RJ) and in the borders with the states of São Paulo, Minas Gerais and Espírito Santo with the State of Rio de Janeiro. The data were submitted to quality analysis (physical and climatic limit and, space-time tendency) and gap filling, based on simple linear regression analysis, associated with the prediction band (p < 0.05 or 0.01), in addition to the Z-score (3, 4 or 5). Next, homogeneity analysis was applied to the continuous series, using the method of cumulative residuals. The coefficients of determination (r²) between the assessed series and the reference series were greater than 0.70 for gap filling both for the supervised and unsupervised approaches. In the analysis of data homogeneity, supervised and unsupervised approaches were effective in selecting homogeneous series, in which five out of the nine final stations were homogeneous (p > 0.9). In the other series, the homogeneity break points were identified and the simple linear regression method was applied for their homogenization. The proposed method was effective to consist of the rainfall series and allows the use of these data in climate studies.

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