A MCMC-based maximum entropy copula method for bivariate drought risk analysis of the Amu Darya River Basin

2020 ◽  
Vol 590 ◽  
pp. 125502
Author(s):  
X. Yang ◽  
Y.P. Li ◽  
Y.R. Liu ◽  
P.P. Gao
Keyword(s):  
Risk Analysis ◽  
Maximum Entropy ◽  
River Basin ◽  
Drought Risk ◽  
Amu Darya ◽  
Copula Method ◽  
Amu Darya River

First records of Gobio nigrescens and Gobio sibiricus (Cypriniformes: Gobionidae) from the Amu Darya River basin, Uzbekistan

2020 ◽  
Vol 36 (2) ◽  
pp. 235-239
Author(s):  
Bakhtiyor Sheraliev ◽  
Sirojiddin Allayarov ◽  
Zuogang Peng
Keyword(s):  
River Basin ◽  
Amu Darya ◽  
Amu Darya River

scholarly journals A maximum entropy copula-based frequency analysis method for assessing bivariate drought risk: a case study of the Kaidu River Basin

2021 ◽  
Author(s):  
X. Yang ◽  
Y. P. Li ◽  
G. H. Huang
Keyword(s):  
Maximum Entropy ◽  
River Basin ◽  
Frequency Analysis ◽  
Return Period ◽  
Drought Risk ◽  
Return Periods ◽  
Drought Frequency ◽  
Joint Return ◽  
Joint Return Period ◽  
Kaidu River

Abstract In this study, a maximum entropy copula-based frequency analysis (MECFA) method is developed through integrating maximum entropy, copulas and frequency analysis into a general framework. The advantages of MECFA are that the marginal modeling requires no assumption and joint distribution preserves the dependence structure of drought variables. MECFA is applied to assessing bivariate drought frequency in the Kaidu River Basin, China. Results indicate that the Kaidu River Basin experienced 28 drought events during 1958–2011, and drought inter-arrival time is 10.8 months. The average duration is 6.2 months (severity 4.6), and the most severe drought event lasts for 35 months (severity 41.2) that occurred from June 1977 to March 1980. Results also disclose that hydrological drought index (HDI) 1 is suitable for drought frequency analysis in target year of return periods of 5 and 10, HDI 3, HDI 6 and HDI 12 are fit for the target year of return periods of 20, 50 and 100. The joint return period can be used as the upper bound of the target return period, and the joint return period that either duration or severity reaches the drought threshold can be used as the lower bound of the target return period.

scholarly journals Projection of Droughts in Amu Darya River Basin for Shared Socioeconomic Pathways

2021 ◽  
Author(s):  
Obaidullah Salehie ◽  
Mohammed Magdy Hamed ◽  
Tarmizi bin Ismail ◽  
Shamsuddin Shahid
Keyword(s):  
River Basin ◽  
Climate Models ◽  
Potential Evapotranspiration ◽  
Global Climate ◽  
Global Climate Models ◽  
Multimodel Ensemble ◽  
Amu Darya ◽  
Near Future ◽  
Far Future ◽  
Amu Darya River

Abstract Droughts significantly affect socioeconomic and the environment primarily by decreasing the water availability of a region. This study aims to assess the changes in drought characteristics in Central Asia's transboundary Amu Darya river basin for four shared socioeconomic pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5). The precipitation, maximum and minimum temperature (Pr, Tmx and Tmn) simulations of 19 global climate models (GCMs) of the coupled model intercomparison project phase 6 (CMIP6) were used to select the best models to prepare the multimodel ensemble (MME). The standard precipitation evapotranspiration index (SPEI) was used to estimate droughts for multiple timescales from Pr and potential evapotranspiration (PET) derived from Tmx and Tmn. The changes in the frequency and spatial distribution of droughts for different severities and timescales were evaluated for the two future periods, 2020–2059 and 2060-2099, compared to the base period of 1975-2014. The study revealed four GCMs, AWI-CM-1-1-MR, CMCC-ESM2, INM-CM4-8 and MPI-ESM1-2-LR, as most suitable for projections of droughts in the study area. The multimodel ensemble (MME) mean of the selected GCMs showed a decrease in Pr by -3 to 12% in the near future and a change in the range of 3 to -9% in the far future in most parts of the basin for different SSPs. The PET showed almost no change in most parts of the basin in the near future and an increase in the range of 10 to 70% in the far future. The change (%) in projected drought occurrence showed to noticeably decrease in the near future, particularly for moderate droughts by up to ≤-50% for SSP5-8.5 and an increase in the far future by up to ≥30% for SSP3-7.0. The increase in all severities of droughts was projected mostly in the center and northwest of the basin. Overall, the results showed a drought shift from the east to the northwest of the basin in the future.

scholarly journals Maximum Entropy-Copula Method for Hydrological Risk Analysis under Uncertainty: A Case Study on the Loess Plateau, China

Entropy ◽  
2017 ◽  
Vol 19 (11) ◽  
pp. 609 ◽  
Author(s):  
Aijun Guo ◽  
Jianxia Chang ◽  
Yimin Wang ◽  
Qiang Huang ◽  
Zhihui Guo
Keyword(s):  
Risk Analysis ◽  
Maximum Entropy ◽  
Loess Plateau ◽  
The Loess Plateau ◽  
Copula Method

scholarly journals Water Balance Analysis Based on a Quantitative Evapotranspiration Inversion in the Nukus Irrigation Area, Lower Amu River Basin

2020 ◽  
Vol 12 (14) ◽  
pp. 2317 ◽  
Author(s):  
Zhibin Liu ◽  
Yue Huang ◽  
Tie Liu ◽  
Junli Li ◽  
Wei Xing ◽  
...  
Keyword(s):  
Water Balance ◽  
River Basin ◽  
Water Consumption ◽  
Correlation Coefficients ◽  
Quantitative Relationship ◽  
Aral Sea ◽  
Irrigation Area ◽  
Amu Darya ◽  
Growing Seasons ◽  
Amu Darya River

Human activities are mainly responsible for the Aral Sea crisis, and excessive farmland expansion and unreasonable irrigation regimes are the main manifestations. The conflicting needs of agricultural water consumption and ecological water demand of the Aral Sea are increasingly prominent. However, the quantitative relationship among the water balance elements in the oasis located in the lower reaches of the Amu Darya River Basin and their impact on the retreat of the Aral Sea remain unclear. Therefore, this study focused on the water consumption of the Nukus irrigation area in the delta of the Amu Darya River and analyzed the water balance variations and their impacts on the Aral Sea. The surface energy balance algorithm for land (SEBAL) was employed to retrieve daily and seasonal evapotranspiration (ET) levels from 1992 to 2018, and a water balance equation was established based on the results of a remote sensing evapotranspiration inversion. The results indicated that the actual evapotranspiration (ETa) simulated by the SEBAL model matched the crop evapotranspiration (ETc) calculated by the Penman–Monteith method well, and the correlation coefficients between the two ETa sources were greater than 0.8. The total ETa levels in the growing seasons decreased from 1992 to 2005 and increased from 2005 to 2015, which is consistent with the changes in the cultivated land area and inflows from the Amu Darya River. In 2000, 2005 and 2010, the groundwater recharge volumes into the Aral Sea during the growing season were 6.74×109 m3, 1.56×109 m3 and 8.40×109 m3; respectively; in the dry year of 2012, regional ET exceeded the river inflow, and 2.36×109 m3 of groundwater was extracted to supplement the shortage of irrigation water. There is a significant two-year lag correlation between the groundwater level and the area of the southern Aral Sea. This study can provide useful information for water resources management in the Aral Sea region.

Sign in / Sign up

Export Citation Format

Share Document