Application of Multiple-Temporal Satellite Imagery with UAV Technology to evaluate Post-typhoon Event Remediation Efficiency in Shihmen Reservoir Watershed

2020 ◽  
Author(s):  
Chun-Kai Chen ◽  
Bor-Shiun Lin ◽  
Chih-Hsien Chen ◽  
Chao-Chin Pai
Keyword(s):  
Satellite Imagery ◽  
Water Conservation ◽  
Vegetation Coverage ◽  
Historical Event ◽  
Environment Change ◽  
Remediation Efficiency ◽  
Shihmen Reservoir ◽  
Landslide Process ◽  
Reservoir Watershed ◽  
Typhoon Event

<p>This study utilized multiple-temporal satellite imagery with UAV and IoT technology to evaluate and monitor the post-typhoon event remediation effectiveness of soil and water conservation of Shihmen Reservoir Watershed from 2015 to 2018.</p><p>A combination of the historical event-based landslide inventory and a collection and recent satellite imagery with coverage of the area pre- and post-typhoon MANGKHUT in 2018 were applied to evaluate landslide process, evolution and sediment environment change. In addition, two UAV operations were completed and captured over 160km2 in the 5 sub-watersheds to validate the remediation effectiveness and environmental change.</p><p>The results show that the landslide area within Shihmen Reservoir is less than that of the 1994 typhoon Aere and has no increased tendency. Effective conservation and remediation work can effectively reduce the sediment discharge of meteorological events and decrease the turbidity of the water at the storage point. In addition, the vegetation coverage rate of the entire Shihmen Reservoir watershed is close to 90%. Except for the occasional localized deforestation, the vegetation coverage has gradually stabilized.</p><p>Keywords: Shihmen reservoir, Remediation Efficiency, UAV and IoT Technology</p>

scholarly journals Improvement of the K-Factor of USLE and Soil Erosion Estimation in Shihmen Reservoir Watershed

2019 ◽  
Vol 11 (2) ◽  
pp. 355 ◽  
Author(s):  
Bor-Shiun Lin ◽  
Chun-Kai Chen ◽  
Kent Thomas ◽  
Chen-Kun Hsu ◽  
Hsing-Chuan Ho
Keyword(s):  
Soil Erosion ◽  
Water Conservation ◽  
Large Scale ◽  
Chemical Properties ◽  
Past Research ◽  
Area Of Interest ◽  
K Factor ◽  
Shihmen Reservoir ◽  
The Difference ◽  
Reservoir Watershed

The estimation of soil erosion in Taiwan and many countries of the world is based on the widely used universal soil loss equation (USLE), which includes the factor of soil erodibility (K-factor). In Taiwan, K-factor values are referenced from past research compiled in the Taiwan Soil and Water Conservation Manual, but there is limited data for the downstream area of the Shihmen reservoir watershed. The designated K-factor from the manual cannot be directly applied to large-scale regional levels and also cannot distinguish and clarify the difference of soil erosion between small field plots or subdivisions. In view of the above, this study establishes additional values of K-factor by utilizing the double rings infiltration test and measures of soil physical–chemical properties and increases the spatial resolution of K-factor map for Shihmen reservoir watershed. Furthermore, the established values of K-factors were validated with the designated value set at Fuxing Sanmin from the manual for verifying the correctness of estimates. It is found that the comparative results agree well with established estimates within an allowable error range. Thus, the K-factors established by this study update the previous K-factor system and can be spatially estimated for any area of interest within the Shihmen reservoir watershed and improving upon past limitations.

scholarly journals Impacts of climate and vegetation on actual evapotranspiration in typical arid mountainous regions using a Budyko-Based framework

2020 ◽  
Author(s):  
Yuanhui Yu ◽  
Yuyan Zhou ◽  
Weihua Xiao ◽  
Benqing Ruan ◽  
Fan Lu ◽  
...  
Keyword(s):  
Climatic Factor ◽  
Actual Evapotranspiration ◽  
Vegetation Coverage ◽  
Dominant Factor ◽  
Contributing Factors ◽  
Mountainous Regions ◽  
Production Improvement ◽  
Negative Effect ◽  
Reservoir Watershed ◽  
Seasonal Index

Abstract It is important to understand how actual evapotranspiration (ETa) changes and what the dominant contributing factors are. This study investigated the impacts of climatic factor and vegetation coverage on the variations of ETa using a Budyko-based framework. Climatic seasonal index and vegetation coverage index were selected as indicating factors. Two reservoir watersheds, i.e. the Wangkuai Reservoir Watershed and the Xidayang Reservoir Watershed, of the Daqing River Basin were selected as case studies. Also, relationships between the ETa and climatic and vegetation factors were analyzed. Results showed that the improved vegetation conditions positively contributed to the ETa changes, leading to an increase of 42.15 and 58.56 mm of ETa in the two watersheds, while the increasing climate seasonality had a negative effect, resulting in a drop of 11.48 and 13.47 mm of ETa. Vegetation coverage was recognized as the dominant factor to the changes of ETa, compared to the climatic factor. Our research could offer supporting information for water resources management, agricultural production improvement and eco-environment construction in arid regions.

scholarly journals Wavelet Support Vector Machines for Forecasting Precipitation in Tropical Cyclones: Comparisons with GSVM, Regression, and MM5

2012 ◽  
Vol 27 (2) ◽  
pp. 438-450 ◽  
Author(s):  
Chih-Chiang Wei
Keyword(s):  
Statistical Models ◽  
Mesoscale Model ◽  
Gaussian Kernel ◽  
Support Vector ◽  
State University ◽  
Rainfall Prediction ◽  
Fifth Generation ◽  
Shihmen Reservoir ◽  
Reservoir Watershed ◽  
Lag Times

Abstract This study presents two support vector machine (SVM) based models for forecasting hourly precipitation during tropical cyclone (typhoon) events. The two SVM-based models are the traditional Gaussian kernel SVMs (GSVMs) and the advanced wavelet kernel SVMs (WSVMs). A comparison between the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) and statistical models, including SVM-based models and linear regressions (regression), was made in terms of performance of rainfall prediction at the Shihmen Reservoir watershed in Taiwan. Data from 73 typhoons affecting the Shihmen Reservoir watershed were included in the analysis. This study designed six attribute combinations with different lag times for the forecast target. The modified RMSE, bias, and estimated threat score (ETS) results were employed to assess the predicted outcomes. Results show that better attribute combinations for typhoon climatologic characteristics and typhoon precipitation predictions occurred at 0-h lag time with modified RMSE values of 0.288, 0.257, and 0.296 in GSVM, WSVM, and the regression, respectively. Moreover, WSVM having average bias and ETS values close to 1.0 gave better predictions than did the GSVM and regression models. In addition, Typhoons Zeb (1998) and Nari (2001) were selected for comparison between the MM5 model output and the developed statistical models. Results showed that the MM5 tended to overestimate the peak and cumulative rainfall amounts while the statistical models were inclined to yield underestimations.

scholarly journals An Approach of Identifying and Extracting Urban Commercial Areas Using the Nighttime Lights Satellite Imagery

2020 ◽  
Vol 12 (6) ◽  
pp. 1029
Author(s):  
Xuzhe Duan ◽  
Qingwu Hu ◽  
Pengcheng Zhao ◽  
Shaohua Wang ◽  
Mingyao Ai
Keyword(s):  
Satellite Imagery ◽  
Spatial Data ◽  
Large Scale ◽  
Weather Conditions ◽  
Spatial Data Analysis ◽  
Vegetation Coverage ◽  
Economic Activities ◽  
Traditional Methods ◽  
Detection Model ◽  
Nighttime Lights

Urban commercial areas can reflect the spatial distribution of business activities. However, the scope of urban commercial areas cannot be easily detected by traditional methods because of difficulties in data collection. Considering the positive correlation between business scale and nighttime lighting, this paper proposes a method of urban commercial areas detection based on nighttime lights satellite imagery. First, an imagery preprocess model is proposed to correct imageries and improve efficiency of cluster analysis. Then, an exploratory spatial data analysis and hotspots clustering method is employed to detect commercial areas by geographic distribution metric with urban commercial hotspots. Furthermore, four imageries of Wuhan City and Shenyang City are selected as an example for urban commercial areas detection experiments. Finally, a comparison is made to find out the time and space factors that affect the detection results of the commercial areas. By comparing the results with the existing map data, we are convinced that the nighttime lights satellite imagery can effectively detect the urban commercial areas. The time of image acquisition and the vegetation coverage in the area are two important factors affecting the detection effect. Harsh weather conditions and high vegetation coverage are conducive to the effective implementation of this method. This approach can be integrated with traditional methods to form a fast commercial areas detection model, which can then play a role in large-scale socio-economic surveys and dynamic detection of commercial areas evolution. Hence, a conclusion can be reached that this study provides a new method for the perception of urban socio-economic activities.

scholarly journals Impact of Urbanization and Climate on Vegetation Coverage in the Beijing–Tianjin–Hebei Region of China

2019 ◽  
Vol 11 (20) ◽  
pp. 2452 ◽  
Author(s):  
Qian Zhou ◽  
Xiang Zhao ◽  
Donghai Wu ◽  
Rongyun Tang ◽  
Xiaozheng Du ◽  
...  
Keyword(s):  
Urban Areas ◽  
Core Area ◽  
Vegetation Coverage ◽  
Effect Of Temperature ◽  
Environment Change ◽  
Regional Environment ◽  
Rapid Urbanization ◽  
Important Indicator ◽  
Artificial Surface ◽  
Bth Region

Worldwide urbanization leads to ecological changes around urban areas. However, few studies have quantitatively investigated the impacts of urbanization on vegetation coverage so far. As an important indicator measuring regional environment change, fractional vegetation cover (FVC) is widely used to analyze changes in vegetation in urban areas. In this study, on the basis of a partial derivative model, we quantified the effect of temperature, precipitation, radiation, and urbanization represented as nighttime light on vegetation coverage changes in the Beijing–Tianjin–Hebei (BTH) region during its period of rapid resident population growth from 2001 to 2011. The results showed that (1) the FVC of the BTH region varied from 0.20 to 0.26, with significant spatial heterogeneity. The FVC increased in small cities such as Cangzhou and in the Taihang Mountains, while it decreased in megacities with populations greater than 1 million, such as Beijing and Zhangjiakou Bashang. (2) The BTH region experienced rapid urbanization, with the area of artificial surface increasing by 18.42%. From the urban core area to the fringe area, the urbanization intensity decreased, but the urbanization rate increased. (3) Urbanization and precipitation had the greatest effect on FVC changes. Urbanization dominated the FVC changes in the expanded area, while precipitation had the greatest impacts on the FVC changes in the core area. For future studies on the major influencing factors of FVC changes, quantitative analysis of the contribution of urbanization to FVC changes in urban regions is crucial and will provide scientific perspectives for sustainable urban planning.

scholarly journals Estimating sediment delivery ratio by stream slope and relief ratio

2018 ◽  
Vol 192 ◽  
pp. 02040 ◽  
Author(s):  
Kieu Anh Nguyen ◽  
Walter Chen
Keyword(s):  
Soil Erosion ◽  
Storage Capacity ◽  
Length Ratio ◽  
Delivery Ratio ◽  
Sediment Delivery Ratio ◽  
Sediment Delivery ◽  
Transportation Process ◽  
Shihmen Reservoir ◽  
Reservoir Watershed ◽  
Steep Terrain

Nowadays, the storage capacity of a reservoir reduced by sediment deposition is a concern of many countries in the world. Therefore, understanding the soil erosion and transportation process is a significant matter, which helps to manage and prevent sediments entering the reservoir. The main objective of this study is to examine the sediments reaching the outlet of a basin by empirical sediment delivery ratio (SDR) equations and the gross soil erosion. The Shihmen reservoir watershed is used as the study area. Because steep terrain is a characteristic feature of the study area, two SDR models that depend on the slope of the mainstream channel and the relief-length ratio of the watershed are chosen. It is found that the Maner (1958) model, which uses the relief-length ratio, is the better model of the two. We believe that this empirical research improves our understanding of the sediment delivery process occurring in the study area.

Acquisitions of Vegetation Coverage and Cultivated Land Occupation Ratio of Taiyuan Valley Plain for Example Using CBERS-02B CCD Image

2012 ◽  
Vol 518-523 ◽  
pp. 5663-5667
Author(s):  
Shi Wei Li ◽  
Ji Long Zhang ◽  
Jian Sheng Yang
Keyword(s):  
Remote Sensing ◽  
Water Conservation ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Remote Sensing Image ◽  
Google Earth ◽  
Vegetation Coverage ◽  
Cultivated Land ◽  
Land Occupation ◽  
Coverage Ratio

Vegetation covering situation is very important for the quality of air quality, soil and water conservation ability and soil forming in an area. By using the remote sensing image of Taiyuan Valley Plain, the application of Normalized Difference Vegetation Index (NDVI) and unsupervised classification, the vegetation coverage map which includes non-cultivated land disposition and cultivated land disposition was obtained using ERDAS Imagine software. To evaluate the accuracy of the results, 200 points were sampled randomly, the high spatial resolution remote sensing image from Google Earth was used as the reference. The overall classification accuracy is 82%, with the Kappa statistic of 0.81. By counting the totally pixel acreage, it was gotten that the vegetation coverage was 46% and the cultivated land coverage ratio was 31% in the study area.

Assessment on 2000-2010 Ecosystem Function Changes of Yiwulvshan National Nature Scenic Area

2014 ◽  
Vol 1051 ◽  
pp. 489-494
Author(s):  
Xiao Chen Wang ◽  
Jing Hai Zhu ◽  
Yuan Man Hu ◽  
Wei Ling Liu
Keyword(s):  
Remote Sensing ◽  
Ecosystem Function ◽  
Primary Productivity ◽  
Water Conservation ◽  
Net Primary Productivity ◽  
Remote Sensing Data ◽  
Vegetation Coverage ◽  
The Past ◽  
Remote Sensing Technology ◽  
Sensing Technology

Based on the remote-sensing data and ground data, this study is conducted on the ecosystem function of Yiwulvshan National Nature Scenic Area (hereinafter as “Yiwulvshan Scenic Area”) from 2000 to 2010 with the GIS (geographic information system) and RS (remote sensing) technology, so as to provide reference for better environmental protection of the scenic area. It is shown from the results that there is no obvious change of land use in Yiwulvshan Scenic Area; while the capacity for soil and water conservation is slightly improved mainly due to increase of vegetation coverage; the vegetation net primary productivity declines somewhat about 5.27% in past 10 years; and biodiversity is slightly increased. As a whole, the ecosystem function of Yiwulvshan Scenic Area basically kept stable in the past 10 years, which indicated that the existing regulations can effectively protect the ecological function of the Scenic Area.

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