scholarly journals Spatial Distribution of Precipitation in Huang-Huai-Hai River Basin between 1961 to 2016, China

2019 ◽  
Vol 16 (18) ◽  
pp. 3404 ◽  
Author(s):  
Yong Yuan ◽  
Denghua Yan ◽  
Zhe Yuan ◽  
Jun Yin ◽  
Zhongnan Zhao
Keyword(s):  
Spatial Distribution ◽  
River Basin ◽  
Extreme Precipitation ◽  
Extreme Value Distribution ◽  
Precipitation Intensity ◽  
Generalized Extreme Value Distribution ◽  
Grid Data ◽  
Weighting Method ◽  
Distribution Method ◽  
Distance Weighting

The Huang-huai-hai River Basin is one of the most economically developed areas, but is also heavily impacted by drought and flood disasters. Research on the precipitation feature of the Huang-huai-hai River Basin is of great importance to the further discussion of the cause of flood disaster. Based on the selected meteorological stations of the study area from 1961–2016, the inverse distance weighting method was used to get daily precipitation grid data. Interannual variation of precipitation intensity and cover area of different precipitation classes was analyzed. The generalized extreme-value distribution method was used to analyze the spatial distribution of extreme precipitation. The results show that: (1) decrease of accumulated precipitation in light precipitation year and moderate precipitation year might be the reason why the precipitation in the whole basin decreased, but the coefficient of variation (CV) of different classes of precipitation and precipitation days does not change significantly; (2) since the cover area of precipitation > 50 mm and precipitation intensity both decreased, the extreme precipitation of the whole basin may be decreasing; (3) extreme precipitation mainly occurred in the loess plateau in the northeast of Huang-huai-hai River Basin, Dabieshan in the middle of Huang-huai-hai River Basin and other areas.

scholarly journals Spatial Distribution of Soil Nutrients in Farmland in a Hilly Region of the Pearl River Delta in China Based on Geostatistics and the Inverse Distance Weighting Method

Agriculture ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 50
Author(s):  
Rumi Wang ◽  
Runyan Zou ◽  
Jianmei Liu ◽  
Luo Liu ◽  
Yueming Hu
Keyword(s):  
Spatial Distribution ◽  
Pearl River Delta ◽  
Pearl River ◽  
Weighting Method ◽  
Farmland Protection ◽  
The Pearl River Delta ◽  
Hilly Region ◽  
Distance Weighting ◽  
The Pearl River ◽  
Inverse Distance

Soil nutrients are essential factors that reflect farmland quality. Nitrogen, phosphorus, and potassium are essential elements for plants, while silicon is considered a “quasi-essential” element. This study investigated the spatial distribution of plant nutrients in soil in a hilly region of the Pearl River Delta in China. A total of 201 soil samples were collected from farmland topsoil (0–20 cm) for the analysis of total nitrogen (TN), available phosphorus (AP), available potassium (AK), and available silicon (ASi). The coefficients of variation ranged from 47.88% to 76.91%. The NSRs of TN, AP, AK, and ASi were 0.15, 0. 07, 0.12, and 0.13, respectively. The NSRs varied from 0.02 to 0.20. All variables exhibited weak spatial dependence (R2 < 0.5), except for TN (R2 = 0.701). After comparing the prediction accuracy of the different methods, we used the inverse distance weighting method to analyze the spatial distribution of plant nutrients in soil. The uniform spatial distribution of AK, TN overall showed a trend of increasing from northeast to southwest, and the overall spatial distribution of AP and ASi showed that the northeast was higher than the southwest. This study provides support for the delimitation of basic farmland protection areas, the formulation of land use spatial planning, and the formulation of accurate farmland protection policies.

scholarly journals High-resolution analysis of 1 day extreme precipitation in Sicily

2015 ◽  
Vol 15 (10) ◽  
pp. 2347-2358 ◽  
Author(s):  
M. Maugeri ◽  
M. Brunetti ◽  
M. Garzoglio ◽  
C. Simolo
Keyword(s):  
High Resolution ◽  
Extreme Precipitation ◽  
Human Life ◽  
Extreme Value Distribution ◽  
Generalized Extreme Value Distribution ◽  
Return Level ◽  
Regional Frequency Analysis ◽  
Economic Losses ◽  
Data Set ◽  
High Quantiles

Abstract. Sicily, a major Mediterranean island, has experienced several exceptional precipitation episodes and floods during the last century, with serious damage to human life and the environment. Long-term, rational planning of urban development is indispensable to protect the population and to avoid huge economic losses in the future. This requires a thorough knowledge of the distributional features of extreme precipitation over the complex territory of Sicily. In this study, we perform a detailed investigation of observed 1 day precipitation extremes and their frequency distribution, based on a dense data set of high-quality, homogenized station records in 1921–2005. We estimate very high quantiles (return levels) corresponding to 10-, 50- and 100-year return periods, as predicted by a generalized extreme value distribution. Return level estimates are produced on a regular high-resolution grid (30 arcsec) using a variant of regional frequency analysis combined with regression techniques. Results clearly reflect the complexity of this region, and show the high vulnerability of its eastern and northeastern parts as those prone to the most intense and potentially damaging events.

Evaluation of the Ecological Security in Shiyang River Basin Based on Grid GIS and PSR Model

2013 ◽  
Vol 864-867 ◽  
pp. 1042-1046
Author(s):  
Wei Wei ◽  
Bin Bin Xie
Keyword(s):  
Spatial Distribution ◽  
River Basin ◽  
Evaluation System ◽  
Principal Component ◽  
Ecological Security ◽  
Gis Technology ◽  
Weighting Method ◽  
Shiyang River Basin ◽  
Landscape Patches ◽  
Regional Ecology

With the support of GIS technology, in this paper, each index in the evaluation system was set to the spatial expression of 100m×100m grid scale. Subsequently, the spatial principal component analysis and hierarchy process-combination weighting method were used to express the spatial distribution of regional ecology security in study area. Some results show that:(1)The spatial distribution differences of regional ecology security are very obvious. (2)The maximum of SESI is 87.14 in Liangzhou District and its surroundings. Comparatively, the minimum value is 43.96 in north Minqin and edge of Tengery desert. This weakens interaction on ecological flowing in the basin as well as the capacity of ecological restoration between landscape patches. So the polarization of the watershed ecological security will become more seriously. (3)The ecological security and sustainable development of Shiyang River Basin are still in class of III(Threaten security) and class IV(insecurity).

Spatial effects on extreme precipitation in the coastal areas of southeast China

2020 ◽  
Author(s):  
Weikang Qian ◽  
Xun Sun
Keyword(s):  
Extreme Precipitation ◽  
Extreme Value Distribution ◽  
Coastal Areas ◽  
Generalized Extreme Value Distribution ◽  
Precipitation Event ◽  
Human Society ◽  
Spatial Effects ◽  
Southeast China ◽  
Spatial Factors ◽  
Daily Precipitation Data

&lt;p&gt;Extreme precipitation event, along with its secondary disasters, is one of the largest natural hazards leading to massive loss in human society. In the coastal areas of southeast china, tropical cyclones (TC) frequently visit the region with intensive precipitation in summer and autumn. Besides TC induced extreme precipitation, convectional precipitation is an alternative reason of extreme precipitation. This study investigated the spatial effects of the extreme precipitation during the raining season for both TC induced and non-TC induced extreme precipitation. The seasonal maximum daily precipitation data through 94 stations in southeast coastal areas of China from 1964 to 2013 were used. We developed a hierarchical Bayesian model with generalized extreme value distribution (GEV) to quantitatively assess the effects of spatial factors on the extreme precipitation. TC induced and non-TC induced extreme precipitation are modelled separately. It was found that the spatial factors that affect the TC induced and non-TC induced extreme precipitation are clearly different. For the TC induced extreme precipitation, the distance to the coastline has been found to be a significant spatial covariate that affects both the location and scale parameter of GEV across the whole areas, while spatial factors are diverse in different locations for non-TC induced extreme precipitation.&lt;/p&gt;

scholarly journals Hydrological regionalization of streamflows for the Tocantins River Basin in Brazilian Cerrado biome

2021 ◽  
Vol 16 (6) ◽  
pp. 1-19
Author(s):  
Jéssica Assaid Martins Rodrigues ◽  
Marcelo Ribeiro Viola ◽  
Carlos Rogério de Mello ◽  
Marco Antônio Vieira Morais
Keyword(s):  
Water Resources ◽  
River Basin ◽  
Extreme Value Distribution ◽  
Kendall Test ◽  
Generalized Extreme Value Distribution ◽  
Brazilian Cerrado ◽  
Annual Streamflow ◽  
Cerrado Biome ◽  
Resource Managers ◽  
Tocantins River

The Brazilian Cerrado biome is the largest and richest tropical savanna in the world and is among the 25 biodiversity hotspots identified worldwide. However, the lack of adequate hydrological monitoring in this region has led to problems in the management of water resources. In order to provide tools for the adequate management of water resources in the Brazilian Cerrado biome region, this paper develops the regionalization of maximum, mean and minimum streamflows in the Tocantins River Basin (287,405.5 km2), fully located in the Brazilian Cerrado biome. The streamflow records of 32 gauging stations in the Tocantins River Basin are examined using the Mann-Kendall test and the hydrological homogeneity non-parametric index-flood method. One homogeneous region was identified for the estimate of the streamflows Qltm (long-term mean streamflow), Q90% (streamflow with 90% of exceeding time), Q95% (streamflow with 95% of exceeding time) and Q7,10 (minimum annual streamflow over 7 days and return period of 10 years). Two homogeneous regions were identified for maximum annual streamflow estimation and the Generalized Extreme Value distribution is found to describe the distribution of maximus events appropriately within the both regions. Regional models were developed for each streamflow of each region and evaluated by cross-validation. These models can be used for the estimation of maximum, mean and minimum streamflows in ungauged basins within the Tocantins River Basin within the area boundaries identified. Therefore, the results provided in this paper are valuable tools for practicing water-resource managers in the Brazilian Cerrado biome. Keywords: l-moments, statistical hydrology, water use rights concessions.

scholarly journals Prediction of the Variability of Changes in the Intensity and Frequency of Climate Change Reinforced Multi-Day Extreme Precipitation in the North-Central Vietnam Using General Circulation Models and Generalized Extreme Value Distribution Method

2021 ◽  
Vol 8 ◽  
Author(s):  
Pham Quy Giang
Keyword(s):  
Climate Change ◽  
Extreme Precipitation ◽  
General Circulation ◽  
Extreme Value ◽  
Generalized Extreme Value Distribution ◽  
Generalized Extreme Value ◽  
Distribution Method ◽  
North Central ◽  
The North ◽  
Central Vietnam

Flooding of downstream agricultural fields and cities is normally caused by consecutive days of extreme precipitation in upstream areas. As climate change is widely projected to accelerate the hydrological cycle, concerns about the increase in frequency and intensity of extreme precipitation arise. The present study used Pattern Scaling coupled with Generalized Extreme Value (GEV) distribution to calculate changes in multi-day extreme precipitation in the North Central Vietnam in 2050, 2070, and 2090 under three AR5’s Representative Concentration Pathways RCP2.6, RCP6.0 and RCP8.5. Twenty long-term historical observation stations in the study area with daily data mostly date back to more than 50 years were employed and 5-day maximum total precipitation was analyzed. The results reveal an agreement among the employed GCMs on an increase in the intensity and a shortening of the return periods of extreme precipitation, with the most reinforced trend occurring under RCP8.5, followed by RCP6.0 and then RCP2.6. This indicates that the risk of associated floods is likely to increase, especially under higher RCPs. Therefore, planning and decision making of durable infrastructure along with flood mitigation strategies to cope with such events are recommended.

scholarly journals Insights on the Impacts of Hydroclimatic Extremes and Anthropogenic Activities on Sediment Yield of a River Basin

Earth ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 32-50
Author(s):  
Rocky Talchabhadel ◽  
Jeeban Panthi ◽  
Sanjib Sharma ◽  
Ganesh R. Ghimire ◽  
Rupesh Baniya ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
River Basin ◽  
Extreme Precipitation ◽  
Suspended Sediment Concentration ◽  
Anthropogenic Activities ◽  
Sediment Concentration ◽  
Sediment Flux ◽  
Mountain River ◽  
Ecological Processes ◽  
Precipitation Indices

Streamflow and sediment flux variations in a mountain river basin directly affect the downstream biodiversity and ecological processes. Precipitation is expected to be one of the main drivers of these variations in the Himalayas. However, such relations have not been explored for the mountain river basin, Nepal. This paper explores the variation in streamflow and sediment flux from 2006 to 2019 in central Nepal’s Kali Gandaki River basin and correlates them to precipitation indices computed from 77 stations across the basin. Nine precipitation indices and four other ratio-based indices are used for comparison. Percentage contributions of maximum 1-day, consecutive 3-day, 5-day and 7-day precipitation to the annual precipitation provide information on the severity of precipitation extremeness. We found that maximum suspended sediment concentration had a significant positive correlation with the maximum consecutive 3-day precipitation. In contrast, average suspended sediment concentration had significant positive correlations with all ratio-based precipitation indices. The existing sediment erosion trend, driven by the amount, intensity, and frequency of extreme precipitation, demands urgency in sediment source management on the Nepal Himalaya’s mountain slopes. The increment in extreme sediment transports partially resulted from anthropogenic interventions, especially landslides triggered by poorly-constructed roads, and the changing nature of extreme precipitation driven by climate variability.

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