scholarly journals Investigating the Complexity of Runoff Series in the Yangtze River Using Sample Entropy

10.29007/ttss ◽  
2018 ◽  
Author(s):  
Yuankun Wang ◽  
Dong Wang ◽  
Xiaorui Shi
Keyword(s):  
Yangtze River ◽  
Dynamic Change ◽  
Negative Relationship ◽  
Sliding Window ◽  
Sample Entropy ◽  
Spatial Difference ◽  
The Yangtze River ◽  
Runoff Series ◽  
Increasing Trend

Based on sample entropy, we investigated spatial distribution and dynamic change of runoff series complexity with the long-term daily runoff series of main stem in the Yangtze River. The results showed that, complexity of the runoff series show an obvious spatial difference, and an increasing trend from upstream to downstream in the Yangtze River. There are negative relationship between average of runoff sliding window and the corresponding sample entropy, and their peak-to-valley value shows the well corresponding relationships. Complexity of the runoff series at Yichang and Datong stations show a continuous increasing trend, while that of Hankou station an increasing trend after 2000. It could provide scientific reference for understanding of runoff series dynamic evolution in the Yangtze River.

scholarly journals Identification of long-term trends and seasonality in high-frequency water quality data from the Yangtze River basin, China

PLoS ONE ◽  
2018 ◽  
Vol 13 (2) ◽  
pp. e0188889 ◽  
Author(s):  
Weili Duan ◽  
Bin He ◽  
Yaning Chen ◽  
Shan Zou ◽  
Yi Wang ◽  
...  
Keyword(s):  
Water Quality ◽  
High Frequency ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Quality Data ◽  
The Yangtze River ◽  
Water Quality Data ◽  
The Yangtze River Basin ◽  
Long Term Trends

Monitoring permafrost changes in the Yangtze River source region of the Qinghai-Tibetan Plateau using differential SAR interferometry

2020 ◽  
Author(s):  
Lingxiao Wang ◽  
Lin Zhao ◽  
Huayun Zhou ◽  
Shibo Liu ◽  
Xiaodong Huang ◽  
...  
Keyword(s):  
Active Layer ◽  
Yangtze River ◽  
Ground Deformation ◽  
Source Region ◽  
Deformation Monitoring ◽  
Tibet Plateau ◽  
Permafrost Degradation ◽  
The Yangtze River ◽  
Ground Ice

<p>Qinghai-Tibet Plateau (QTP) has the largest high-altitude permafrost zone in the middle and low latitudes. Substantial hydrologic changes have been observed in the Yangtze River source region and adjacent areas in the early 21st century. Permafrost on the QTP has undergone degradation under global warming. The ground leveling observation site near Tangula (33°04′N, 91°56′E) located in the degraded alpine meadow indicates that the ground has subsided 50mm since 2011. The contribution of permafrost degradation and loss of ground ice to the hydrologic changes is however still lacking. This study monitors the permafrost changes by applying the Small BAseline Subset InSAR (SBAS-InSAR) technique using C-band Sentinel-1 datasets during 2014-2019. The ground deformation over permafrost terrain is derived in spatial and temporal scale, which reflects the seasonal freeze-thaw cycle in the active layer and long-term thawing of ground ice beneath the active layer. Results show the seasonal thaw displacement exhibits a strong correlation with surficial geology contacts. The ground leveling data is used to validate the ground deformation monitoring results. Then, the ground deformation characteristics are analyzed against the landscape units. Last, the long-term inter-annual displacement value is used to estimate the water equivalent of ground ice melting.</p>

Research on Continuous Traffic Safety Evaluation of Yangtze River Shipping

2013 ◽  
Vol 442 ◽  
pp. 617-622 ◽  
Author(s):  
Kai Jin Xu ◽  
Qin Liu ◽  
Lei Xu
Keyword(s):  
Traffic Safety ◽  
Yangtze River ◽  
Evaluation Model ◽  
Safety Evaluation ◽  
Scientific Basis ◽  
The Yangtze River ◽  
Affecting Factors ◽  
Analytic Hierarchy ◽  
Safety Mechanism

Traffic safety has characteristics of long-term and arduous, and continued safety is the essential goal of safety, the continued safety of Yangtze River shipping is not only an important part of Yangtze River safety culture, but also a concrete manifestation of long-term safety mechanism. This paper analyzes the affecting factors of the Yangtze River shipping safety, from the perspective of sustainable safety, extract with operational index of safety evaluation, construct of the Yangtze River shipping safety evaluation model, combined with the improved analytic hierarchy process , estimates the main aspects that affects the continued safety of the Yangtze River shipping , and the research results can provide scientific basis for the long-term management of Yangtze River shipping safety.

scholarly journals ANALYSIS OF TREND AND VARIABILITY OF SUMMER SEASON VISIBILITY AND TEMPERATURE IN SAHEL ZONE OF NIGERIA

2020 ◽  
Vol 4 (3) ◽  
pp. 489-495
Author(s):  
Mukhtar Balarabe ◽  
Bello Saadu
Keyword(s):  
Meteorological Data ◽  
Negative Relationship ◽  
Negative Temperature ◽  
Summer Season ◽  
Climate Data ◽  
The Past ◽  
Increasing Trend ◽  
Relationship Of ◽  
Threat To Life

The variation of climate in the past on different time scale in Nigeria has generated a lot of concern and is still posing a threat to life and properties. Meteorologist and climatologist in Nigeria are working hard to address this problem. This study assessed the recent trend and variability of summer season`s visibility and temperature for Sahel zone of Nigeria. The long-term (1988-2017) summer seasons meteorological data derived from National Oceanic Atmospheric Agency-National Climate Data Centre (NOAA-NCDC) were used. A significant decreasing trend in visibility and increasing trend in temperature were detected during the entire period of study. The overall averages were 14.71 ± 4.17 km and 24.54 ± 4.19  respectively. The trends were found more significance in the last ten years. The Decades` means are 19.38± 3.05, 13.76 ± 2.09, 10.98 ± 1.28 km  and 20.60 ± 4.72◦C, 25.78 ± 2.54 ◦C and 27.25 ± 0.79  ◦C for the first, second and third decades respectively. Standardize anomaly chart revealed that over the period of study, positive visibility anomaly correspond to negative temperature anomaly and vice visa. Their correlation at p< 0.05 significant level showed a negative relationship of 0.54 over the thirty years period. However, decade analysis showed a positive correlation of 0.47 and negative correlations of 0.61 and 0.74 for the first, second and third decades respectively. These suggest that summer season of the recent decades are dustier than the previous ones and that, summer season of the recent decades become hotter than the previous decades

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