scholarly journals Assessment of hydrologic regime considering the distribution of hydrologic parameters

2017 ◽  
Vol 18 (3) ◽  
pp. 875-885 ◽  
Author(s):  
Yang Liu ◽  
Shengle Cao ◽  
Yuheng Yang ◽  
Xi Zhang
Keyword(s):  
Water Resource Management ◽  
Goodness Of Fit ◽  
Human Impacts ◽  
Hydrologic Regime ◽  
Mean Flow ◽  
Hydrologic Alteration ◽  
Parameter Estimations ◽  
Goodness Of Fit Tests ◽  
Multi Attribute Decision Making ◽  
Increasing Trends

Abstract To assess hydrologic regime more comprehensively using the distribution of hydrologic parameters, the probability density function of each parameter is obtained from parameter estimations and goodness-of-fit tests based on the principle of maximum entropy. Then, the Shannon entropy and weights for a multi-attribute decision-making process are used to calculate the degree of hydrologic alteration. This method is applied to the Xiaoqing River in the city of Jinan, China. The results indicate that the diversities of the monthly mean flow and annual extreme flow show decreasing trends that are attributable to human impacts, while the diversities of the timing of annual extreme, high and low flows, and the rate and frequency of flooding show increasing trends. Meanwhile, the overall degree of hydrologic alteration of the Xiaoqing River in Jinan is 0.747, which belongs to a change in the height. Thus, we suggest that the timing and volume of inter-basin water transfer should be reasonably regulated and that the regulation of peak flooding times and peak flow should be strengthened to make them conform to ecological characteristics during the water resource management of the Xiaoqing River.

scholarly journals Development of a General Equation for Intensity-Duration-Frequency (IDF): Iraq

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Hasan Mahdi
Keyword(s):  
Water Resource Management ◽  
Goodness Of Fit ◽  
Flash Flood ◽  
Repeated Cycle ◽  
Goodness Of Fit Tests ◽  
Pearson Type ◽  
Chi Squared ◽  
Idf Curves ◽  
Intensity Duration Frequency ◽  
Anderson Darling

In the field of water resource management, rainfall intensity-duration-frequency (IDF) curves are of great importance, especially in the design of hydraulic structures and the assessment of flash-flood risks. The aim of this study is to obtain IDF curves and find empirical equations for rain duration for Al-Najaf city in the southwest of Iraq. Rainfall data for 30 years, from 1989 to 2018, were collected. The practical reduction equation of the Indian Meteorological Department (IMD), with six methods of probability distribution, was used for short intervals (0.25, 0.5, 1, 2, 3, 6, 12, and 24 hours) with a specified recurrence period (100, 50, 25, 10, 5, and 2 years). The Kolmogorov-Smirnov, chi-squared, and Anderson-Darling goodness of fit tests were used with the help of EasyFit 5.6 software. The findings revealed that the highest intensity of rainfall occurs during a repeated cycle of 100 years with a duration of 0.25 hours, while the lowest intensity of rainfall occurs during a repeated cycle of 2 years with a duration of 24 hours. In the results obtained from the six methods, as well as the superiority of the log Pearson type III method, the consistency of the fit tests showed some convergence.

scholarly journals Pan-European Calculation of Hydrologic Stress Metrics in Rivers: A First Assessment with Potential Connections to Ecological Status

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 703 ◽  
Author(s):  
Yiannis Panagopoulos ◽  
Kostas Stefanidis ◽  
Marta Faneca Sanchez ◽  
Frederiek Sperna Weiland ◽  
Rens Van Beek ◽  
...  
Keyword(s):  
River Flow ◽  
Ecological Status ◽  
Hydrologic Regime ◽  
Mean Flow ◽  
Hydrologic Alteration ◽  
Basin Management ◽  
Disturbed Condition ◽  
Daily Time Series ◽  
Good Ecological Status ◽  
Daily Time

The hydrologic regime of a river is one of the factors determining its ecological status. This paper tries to indicate the present hydrologic stress occurring across European rivers on the basis of model integration. This results in a pan-European assessment at the resolution of the functional elementary catchment (FEC), based on simulated daily time-series of river flows from the model PCR-GLOBWB. To estimate proxies of the present hydrologic stress, two datasets of river flow were simulated under the same climate, one from a hypothetic least disturbed condition scenario and the second from the anthropogenic scenario with the actual water management occurring. Indicators describing the rivers’ hydrologic regime were calculated with the indicators of hydrologic alteration (IHA) software package and the river total mean flow and the relative baseflow magnitude over the total flow were used to express the deviations between the two scenarios as proxy metrics of rivers’ hydrologic alteration or hydrologic stress. The alteration results on Europe’s FEC-level background showed that Southern Europe is more hydrologically stressed than the rest of Europe, with greater potential for hydrology to be clearly associated with river segments of unreached good ecological status and high basin management needs.

scholarly journals Dependence Modeling in Energy Markets using Sibuya-type Copulas

2017 ◽  
Vol 6 (3) ◽  
pp. 43
Author(s):  
Nikolai Kolev ◽  
Jayme Pinto
Keyword(s):  
Goodness Of Fit ◽  
Basic Assumption ◽  
Energy Markets ◽  
Dependence Structure ◽  
Dependence Function ◽  
Dependence Modeling ◽  
Goodness Of Fit Tests ◽  
Oil And Natural Gas ◽  
Error Terms ◽  
Time Invariant

The dependence structure between 756 prices for futures on crude oil and natural gas traded on NYMEX is analyzed  using  a combination of novel time-series and copula tools.  We model the log-returns on each commodity individually by Generalized Autoregressive Score models and account for dependence between them by fitting various copulas to corresponding  error terms. Our basic assumption is that the dependence structure may vary over time, but the ratio between the joint distribution of error terms and the product of marginal distributions (e.g., Sibuya's dependence function) remains the same, being time-invariant.  By performing conventional goodness-of-fit tests, we select the best copula, being member of the currently  introduced class of  Sibuya-type copulas.

scholarly journals Goodness-of-Fit Tests for Bivariate Time Series of Counts

Econometrics ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 10
Author(s):  
Šárka Hudecová ◽  
Marie Hušková ◽  
Simos G. Meintanis
Keyword(s):  
Goodness Of Fit ◽  
Probability Generating Function ◽  
Parametric Bootstrap ◽  
Real Data ◽  
Data Sets ◽  
Test Statistics ◽  
Finite Sample ◽  
Generalized Poisson ◽  
Goodness Of Fit Tests ◽  
Monte Carlo Experiments

This article considers goodness-of-fit tests for bivariate INAR and bivariate Poisson autoregression models. The test statistics are based on an L2-type distance between two estimators of the probability generating function of the observations: one being entirely nonparametric and the second one being semiparametric computed under the corresponding null hypothesis. The asymptotic distribution of the proposed tests statistics both under the null hypotheses as well as under alternatives is derived and consistency is proved. The case of testing bivariate generalized Poisson autoregression and extension of the methods to dimension higher than two are also discussed. The finite-sample performance of a parametric bootstrap version of the tests is illustrated via a series of Monte Carlo experiments. The article concludes with applications on real data sets and discussion.

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