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Results 1-7 of 7 (Search time: 0.002 seconds).
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  • Bayesian multi-model projections of extreme hydroclimatic events under RCPs scenarios

    • Authors: Xia, J.; Sun, Q.;  Advisor: -;  Participants: - (2017)

  • A Bayesian multi-model inference framework was used to assess the changes in the occurrence of extreme hydroclimatic events in four major river basins in China (i.e., Liaohe River Basin, Yellow River Basin, Yangtze River Basin, and Pearl River Basin) under RCP2.6, RCP4.5, and RCP8.5 scenarios using multiple global climate model projections from the IPCC Fifth Assessment Report. The results projected more summer days and fewer frost days in 2006–2099. The ensemble prediction shows the Pearl River Basin is projected to experience more summer days than other basins with the increasing trend of 16.3, 38.0, and 73.0 d per 100 years for RCP2.6, RCP4.5 and RCP8.5, respectively. Liaohe River Basin and Yellow River Basin are forecasted to become wetter and warmer with the co-occurrence of in...
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  • Analysis of hydrological variability over the Volta river basin using in-situ data and satellite observations

    • Authors: Awange, J.L.; Ndehedehe, C.E.;  Advisor: -;  Participants: - (2017)

  • By combining satellite altimetry with Gravity Recovery and Climate Experiment derived terrestrial water storage-TWS (2002–2014), this study used a two-step procedure based on spherical harmonic synthesis and statistical decomposition to support the understanding of the Volta basin's natural hydrology and its freshwater systems. Results indicate that Lake Volta contributed 41.6% to the observed increase in TWS over the basin during the 2002–2014 period. While it also coincides with observed decline in net precipitation (−15 mm/yr), the long dry periods in the basin (2001–2007) also contributed to this storage depletion. The Lake Volta shows sensitivity to incoming flows of the Volta river system with a lag spanning between less than one and up to two years. In addition to this, a 4–5...
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  • Assessing suitability of the ACRU hydrological model in a rainforest catchment in Ghana, West Africa

    • Authors: Jewitt, G.P.W.; Aduah, M.S.;  Advisor: -;  Participants: - (2017)

  • The objective of this study was to assess the suitability of the daily time step physical-conceptual ACRU model for hydrological modelling in the Bonsa catchment. Since the catchment is data poor, model calibration was conducted using a careful parameterization and sensitivity analysis, using initial values obtained from literature and field observations, as well as climate data for the period 1987–1999 and 1991 land use. The model performance during calibration and validation was satisfactory, with a monthly NSE of 0.6 and 0.5 and R2 of 0.8 and 0.7, respectively. The model simulated the rise and the recession of the hydrograph well, but during the validation the accumulated monthly streamflows were underestimated by 10%. The main conclusion from this study is that the ACRU hydrolog...
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  • Coupled modeling of land hydrology–regional climate including human carbon emission and water exploitation

    • Authors: Zeng, Y.; Xie, Z.;  Advisor: -;  Participants: - (2017)

  • Carbon emissions and water use are two major kinds of human activities. To reveal whether these two activities can modify the hydrological cycle and climate system in China, we conducted two sets of numerical experiments using regional climate model RegCM4. Results from the first experiment revealed that near-surface air temperature may significantly increase from 2007 to 2059 at a rate exceeding 0.1 °C per decade in most areas across the country; southwestern and southeastern China also showed increasing trends in summer precipitation, with rates exceeding 10 mm per decade over the same period. These effects are believed to be caused by global warming from human carbon emissions. We incorporated a scheme of human water regulation into RegCM4 and conducted the second experiment. Mod...
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  • Soil N, P, and C dynamics of upland and seasonally flooded forests of the Brazilian Pantanal

    • Authors: Pinto, O.B.; Vourlitis, G.L.;  Advisor: -;  Participants: - (2017)

  • Seasonal variations in cerrado nutrient availability and mineralization are poorly understood, especially for “hyperseasonal” cerrado, which experiences both flooding and drought over an annual cycle. Here we quantified seasonal variations in soil ammonium (NH4+), phosphorus (P), and organic C (SOC) concentration and net mineralization in upland and seasonally flooded cerrado forests of the Brazilian Pantanal, and hypothesized that NH4+, P, and SOC concentrations and net mineralization would decline under flooding and increase during the dry season as soil becomes unsaturated. Thus, despite the large seasonal and spatial variations in hydrology, the effects of flooding depended on the particular response variable studied and the season.
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  • Hydrogeochemistry in a relatively unmodified subtropical catchment: Insights regarding the health and aesthetic risks of manganese

    • Authors: Fabbro, L.; Rose, A.K.;  Advisor: -;  Participants: - (2017)

  • Results show that the hydrogeochemistry of Baffle Creek was predominantly driven by rain events, with differing responses to varying magnitudes of rain and discharge. Following a flushing event, dissolved aluminium and nitrate increased in the surface and drinking water, whereas manganese and ammonia were undetectable in the drinking water and occurred only in small concentrations in the surface waters. In contrast, when rainfall events occurred without an associated flush, manganese, iron and ammonia concentrations increased in the drinking water. The hydrochemistry of manganese and iron in the supply chain infrastructure was strongly positively correlated with ammonia, and aluminium correlated with nitrate concentrations. Currently the drinking water supply does not pose a threat ...
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