Comparison of CMIP5 and CMIP6 GCM performance for flood projections in the Mekong River Basin

Study region: Mekong River Basin. Study focus: The Coupled Model Intercomparison Project Phase 6 (CMIP6) recently announced an updated version of general circulation models (GCMs). This study investigated the performance of improved CMIP6 over those of CMIP5 with respect to precipitation and flood representations in the Mekong River Basin (MRB). The correlation and error comparison from the referenced precipitation exhibited a significant improvement in the peak value representation. Hence, the impacts of climate change on future floods in the MRB were simulated and assessed using a distributed rainfall–runoff–inundation model. New hydrological insights for the region: The results indicated that precipitation from CMIP6 had a higher correlation and a lower error coefficient than CMIP5. Similarly, the simulation of GCM ensembles of monthly discharge from CMIP6 exhibited a comparable average value to the observations, whereas CMIP5 underestimated the discharge simulations. The performance of the mean annual peak discharge improved from 37, 220 m3/s (CMIP5) to 45, 423 m3/s (CMIP6) compared to 43, 521 m3/s (observation). The projections of future floods in the MRB from CMIP6 exhibited an increase of annual peak discharge at Chiang Saen, Vientiane, Pakse, and Kratie stations by 10–15%, 20–22%, and 24–29% for the SSP2-4.5 scenario, and 10–18%, 24–29%, and 41–54% for the SSP5-8.5 scenario in the near future (2026–2050), mid-future (2051–2075), and far future (2076–2100), respectively. The statistical K-S test showed significant changes in all stations and projected periods with a p-value < 0.01

Threshold Tolerance of New Genotypes of Pennisetum glaucum (L.) R. Br. to Salinity and Drought

With continued population growth, increasing staple crop production is necessary. However, in dryland areas, this is negatively affected by various abiotic stresses, such as drought and salinity. The field screening of 10 improved genetic lines of pear millet originating from African dryland areas was conducted based on a set of agrobiological traits (i.e., germination rate, plant density, plant maturity rate, forage, and grain yields) in order to understand plant growth and its yield potential responses under saline environments. Our findings demonstrated that genotype had a significant impact on the accumulation of green biomass (64.4% based on two-way ANOVA), while salinity caused reduction in grain yield value. HHVBC Tall and IP 19586 were selected as the best-performing and high-yielding genotypes. HHVBC Tall is a dual purpose (i.e., forage and grain) line which produced high grain yields on marginal lands, with soil salinization up to electrical conductivity (EC) 6–8 dS m−1 (approximately 60–80 mM NaCl). Meanwhile, IP 19586, grown under similar conditions, showed a rapid accumulation of green biomass with a significant decrease in grain yield. Both lines were tolerant to drought and sensitive to high salinity (above 200 mM NaCl). The threshold salinity of HHVBC Tall calculated at the seedling stage was lower than that of IP 19586. Seedling viability of these lines was affected by oxidative stress and membrane peroxidation, and they had decreased chlorophyll and carotenoid biosynthesis. This study demonstrated that ionic stress is more detrimental for the accumulation of green and dry biomass, in combination with increasing the proline and malonic dialdehyde (MDA) contents of both best-performing pearl millet lines, as compared with osmotic stress

Water Quality Monitoring and Geospatial Database Coupled with Hydrological Data of Zeravshan River Basin

Abstract: This paper focuses on water quality monitoring of the main streams, irrigation canals, collector-drainage system of Zeravshan River Basin and on developing a platform for efficient data management and sharing of water quality and hydrological datasets. The water quality monitoring had been carried out from 2005 to 2010 throughout the basin and collected water samples, hydrological, meteorological and economic data indicate that generally water in the downstream part of the basin was in significant low quality. The water contains high concentration of salts and heavy metals that could be dangerous for people livelihood. The water quality datasets are stored in a newly developed web-based geospatial database, coupled with hydrological data collected during many years. The database integrates quantitative and qualitative datasets into spatially-explicit maps which help intuitive data handling and easy sharing for collaboration work. The web-based feature of the database with online access to the visualized maps of hydrological and water quality datasets provides an interactive framework solution for collaboration among those involved in water resources management in Zeravshan river basin

Addressing Water Resources Regulations Policy in Zeravshan River Basin

Water resources security and efficient usage is the main source of conflict over transboundary rivers. Zeravshan a transboundary river in Central Asia is a snow-glacier fed river originating in Tajikistan that use only 4% of its resources and further flows to Uzbekistan, who fully utilize river resources for irrigation. Such disparity in river usage causes Tajikistan to consider heavy investments in hydropower dams that will increase social and political tension between counterparts. The distribution of the available lands for irrigation and income is high in downstream, while upstream argues to have right over water to generate own benefits in producing energy. In this research we analyze impacts of the future dam construction in the middle stream of the Zeravshan river basin through framework of several models to address future policy on the water resources regulation. To balance usage of the water resources between participators to reach a better economic outcomes between argues.Water resources security and efficient usage is the main source of conflict over transboundary rivers. Zeravshan a transboundary river in Central Asia is a snow-glacier fed river originating in Tajikistan that use only 4% of its resources and further flows to Uzbekistan, who fully utilize river resources for irrigation. Such disparity in river usage causes Tajikistan to consider heavy investments in hydropower dams that will increase social and political tension between counterparts. The distribution of the available lands for irrigation and income is high in downstream, while upstream argues to have right over water to generate own benefits in producing energy. In this research we analyze impacts of the future dam construction in the middle stream of the Zeravshan river basin through framework of several models to address future policy on the water resources regulation. To balance usage of the water resources between participators to reach a better economic outcomes between argues

Climate Change Impact and Environment Adaptation in Zeravshan River Basin

We investigated impact of climate change on the Zeravshan river basin and applicable adaptation measures for the future development in the region. This study is focused on two major goals; the first predicting future flow conditions and the second is measures to operate marginal waters in the downstream under future decreased flow condition. Land-surface model SiBUC future projections show a flow increase, accompanied by precipitation decrease in summer and increase in winter. Water availability in late summer will become the main issue as well as changes in seasonality of the runoff and higher temperatures. In the second topic marginal waters potential and quantity calculations has been researched to address water availability in Zeravshan River Basin under climate change impacts. Findings show how plants interact with water and soil environments under stressed conditions. Utilization of both marginal waters and lands under a climate change water scarcity scenario can be a potential way of addressing forage availability without requiring fresh waters from river and improving environment.We investigated impact of climate change on the Zeravshan river basin and applicable adaptation measures for the future development in the region. This study is focused on two major goals; the first predicting future flow conditions and the second is measures to operate marginal waters in the downstream under future decreased flow condition. Land-surface model SiBUC future projections show a flow increase, accompanied by precipitation decrease in summer and increase in winter. Water availability in late summer will become the main issue as well as changes in seasonality of the runoff and higher temperatures. In the second topic marginal waters potential and quantity calculations has been researched to address water availability in Zeravshan River Basin under climate change impacts. Findings show how plants interact with water and soil environments under stressed conditions. Utilization of both marginal waters and lands under a climate change water scarcity scenario can be a potential way of addressing forage availability without requiring fresh waters from river and improving environment

Satellite Remote Sensing of Irrigation in the Aral Sea Basin using Multi-Spectral Sensors

In the Aral Sea basin, due to severe drought and land salinization, land use annually changes due to lack of water resource and local adaptation against salinization. However, these changes have not been recorded in national statistics. Therefore in this research, actual irrigated area was attempted to detect by satellite remote sensing. Diurnal difference of surface temperature was utilized, because surface heat capacity and cooling effect of evapotranspiration are different on irrigated area comparing to surrounding arid non-irrigated zone. The diurnal difference of surface temperature was from MODIS sensor which has 1km and 12 hours resolution. And additionally, land surface model was utilized to remove climatic and geological changes in temperature. As a result, suggested ΔST_[diff] index could detect distribution of irrigated area in main irrigated region in Uzbekistan and ΔST_[diff] value was lower where irrigated area fraction is large. Moreover, monthly and annual change of ΔST_[diff] was smaller from June to August in dry year

Analysis of Temperature Change in Uzbekistan and the Regional Atmospheric Circulation of Middle Asia during 1961–2016

Climate change and shrinking of the Aral Sea have significantly affected the region&rsquo;s temperature variations. Observed interannual changes in Uzbekistan&rsquo;s air temperature compared to the duration of synoptic weather types (SWT) in Middle Asia were analyzed. Nonparametric Mann&ndash;Kendall statistical test and climate trends coefficients were used to identify trend characteristics of observed temperature from 1961&ndash;2016 to the baseline period of 1961&ndash;1990. The results showed increasing temperature trends average to 1 &deg;C in warm and cold half years over Uzbekistan. The 1991&ndash;2016 decadal temperature trend ranged from 0.25 &deg;C/decade in the northwest to 0.52 &deg;C/decade in the center, especially pronounced in the oasis and Aral Sea zones. There were also significant changes in the structure of regional SWT. The main difference in the structure of SWT in Middle Asia relative to the baseline period was expressed in a decrease of cold mass invasion duration from 113.4 to 76.1 days and an increase in low-gradient baric field duration from 65.8 to 134.6 days. The process of anthropogenic warming, which began in Uzbekistan in the 1960s of the twentieth century, has accelerated from the mid-1970s with a higher mean annual air temperature than the baseline period&rsquo;s climate normals (1961&ndash;1990) and is associated with changes in the regional SWT over Middle Asia