Continued global warming has severely affected the spatiotemporal distribution of water resources... more Continued global warming has severely affected the spatiotemporal distribution of water resources and extreme climate events (Brown and Funk 2008; Coumou and Rahmstorf 2012; Hendrix and Salehyan 2012). For example, Oki and Kanae (2006) argued that the spatiotemporal of precipitation is very uneven, resulting in significant time-varying changes in water resources worldwide. Zhang et al. (2007) found that precipitation tends to increase in the mid-latitudes of the northern hemisphere, drying in the subtropical and tropical regions of the northern hemisphere, and moistening in the subtropical and deep-tropical regions of the southern hemisphere.
Water is one of the leading drivers of sustainable development of human social economy (Steffen e... more Water is one of the leading drivers of sustainable development of human social economy (Steffen et al. 2015). With the fast development of economy and the growth of population, the demand of freshwater for human is growing rapidly, and water shortage is one of the major crises of the twenty-first century in the world (Pangare 2006; Pearce 2018; Polizzotto et al. 2008).
Water, land, and energy resources are critical to food security and ultimately to sustainable soc... more Water, land, and energy resources are critical to food security and ultimately to sustainable socio-economic development (Ellabban et al. 2014; Liu et al. 2018; Mohtar et al. 2019). Globally, water withdrawals and water use for food production account for 70 and 90% of total water withdrawals, respectively, (AQUASTAT 2016) and about 10% accounted for energy production and power generation in 2014 (IEA 2016).
Water scarcity is the lack of freshwater resources to meet the ever-increasing demand for water, ... more Water scarcity is the lack of freshwater resources to meet the ever-increasing demand for water, which has been the focus of increasing international, national, and local concern and debate.
Changes in extreme weather and climate extremes have a major negative impact on the natural envir... more Changes in extreme weather and climate extremes have a major negative impact on the natural environment and human society and are one of the most serious challenges to society in addressing climate change (2008).
In recent decades, extreme precipitation events have increased in frequency and magnitude over th... more In recent decades, extreme precipitation events have increased in frequency and magnitude over the world under climate change, causing more water-related disasters such as floods, droughts, tropical cyclones, landslides, and tsunami (Amarnath et al. in Global trends in water-related disasters using publicly available database for hazard and risk assessment, 2017; Dai in Nat Clim Chang 3:52–58, 2013; Milly et al. in Nature 415:514–517, 2002; Trenberth et al. in Nat Clim Chang 4:17–22, 2014).
The importance of surface water quality in controlling the health of aquatic ecosystems, affectin... more The importance of surface water quality in controlling the health of aquatic ecosystems, affecting drinking water resources, and human health is increasingly recognized. Nutrients (mainly nitrogen and phosphorus) are essential for the life of animals and plants, but high concentrations cause many ecological problems (Carpenter et al. 1998; Li et al. 2011; Smith 1982; Sprague and Lorenz 2009).
This paper reports our research effort aiming to investigate the applicability of integrating a h... more This paper reports our research effort aiming to investigate the applicability of integrating a hydrological model and the Hydrological Predictions for the Environment (HYPE) model with a geographic information system (GIS) to examine the effect of land use change and climate change on stream-flows with the Kamo River basin (KRB) located in the central Honshu island, Japan as a case study. The goal of this study was to provide important information for understanding water discharge variations as a basis to guide water resource managers in environmental change decisions in this river basin. This goal was accomplished by two steps (i) comparing HYPE-generated hydrographs for various meteorological data from history to present at current land use (S1 and S2); and (ii) comparing HYPE-generated hydrographs for historical and current land use scenarios at current climate (S3 and S4). The calibration and validation results suggest that HYPE performs well in the case study site for daily simulations. The results of S1–S2 indicate that with the impact of climate change, the trend of annual and seasonal stream flows at the Kamo River Basin outlet would decrease. However, there is no evidence to indicate that the flood risk would be decreasing. The results of S3–S4 show that the conversion of forest, glass and agriculture (FGA) into urban area would induce high peak flows, a reduction in annual evaporation and an increase in annual surface runoff.
Evidence for climate change impacts on the hydro-climatology of Japan is plentiful. The objective... more Evidence for climate change impacts on the hydro-climatology of Japan is plentiful. The objective of the present study was to evaluate the impacts of possible future climate change scenarios on the hydro-climatology of the upper Ishikari River basin, Hokkaido, Japan. The Soil and Water Assessment Tool was set up, calibrated, and validated for the hydrological modeling of the study area. The Statistical DownScaling Model version 4.2 was used to downscale the large-scale Hadley Centre Climate Model 3 Global Circulation Model A2 and B2 scenarios data into finer scale resolution. After model calibration and testing of the downscaling procedure, the SDSM-downscaled climate outputs were used as an input to run the calibrated SWAT model for the three future periods: 2030s (2020–2039), 2060s (2050–2069), and 2090s (2080–2099). The period 1981–2000 was taken as the baseline period against which comparison was made. Results showed that the average annual maximum temperature might increase by 1.80 and 2.01, 3.41 and 3.12, and 5.69 and 3.76 °C, the average annual minimum temperature might increase by 1.41 and 1.49, 2.60 and 2.34, and 4.20 and 2.93 °C, and the average annual precipitation might decrease by 5.78 and 8.08, 10.18 and 12.89, and 17.92 and 11.23% in 2030s, 2060s, and 2090s for A2a and B2a emission scenarios, respectively. The annual mean streamflow may increase for the all three future periods except the 2090s under the A2a scenario. Among them, the largest increase is possibly observed in the 2030s for A2a scenario, up to approximately 7.56%. Uncertainties were found within the GCM, the downscaling method, and the hydrological model itself, which were probably enlarged because only one single GCM (HaDCM3) was used in this study.
Continued global warming has severely affected the spatiotemporal distribution of water resources... more Continued global warming has severely affected the spatiotemporal distribution of water resources and extreme climate events (Brown and Funk 2008; Coumou and Rahmstorf 2012; Hendrix and Salehyan 2012). For example, Oki and Kanae (2006) argued that the spatiotemporal of precipitation is very uneven, resulting in significant time-varying changes in water resources worldwide. Zhang et al. (2007) found that precipitation tends to increase in the mid-latitudes of the northern hemisphere, drying in the subtropical and tropical regions of the northern hemisphere, and moistening in the subtropical and deep-tropical regions of the southern hemisphere.
Water is one of the leading drivers of sustainable development of human social economy (Steffen e... more Water is one of the leading drivers of sustainable development of human social economy (Steffen et al. 2015). With the fast development of economy and the growth of population, the demand of freshwater for human is growing rapidly, and water shortage is one of the major crises of the twenty-first century in the world (Pangare 2006; Pearce 2018; Polizzotto et al. 2008).
Water, land, and energy resources are critical to food security and ultimately to sustainable soc... more Water, land, and energy resources are critical to food security and ultimately to sustainable socio-economic development (Ellabban et al. 2014; Liu et al. 2018; Mohtar et al. 2019). Globally, water withdrawals and water use for food production account for 70 and 90% of total water withdrawals, respectively, (AQUASTAT 2016) and about 10% accounted for energy production and power generation in 2014 (IEA 2016).
Water scarcity is the lack of freshwater resources to meet the ever-increasing demand for water, ... more Water scarcity is the lack of freshwater resources to meet the ever-increasing demand for water, which has been the focus of increasing international, national, and local concern and debate.
Changes in extreme weather and climate extremes have a major negative impact on the natural envir... more Changes in extreme weather and climate extremes have a major negative impact on the natural environment and human society and are one of the most serious challenges to society in addressing climate change (2008).
In recent decades, extreme precipitation events have increased in frequency and magnitude over th... more In recent decades, extreme precipitation events have increased in frequency and magnitude over the world under climate change, causing more water-related disasters such as floods, droughts, tropical cyclones, landslides, and tsunami (Amarnath et al. in Global trends in water-related disasters using publicly available database for hazard and risk assessment, 2017; Dai in Nat Clim Chang 3:52–58, 2013; Milly et al. in Nature 415:514–517, 2002; Trenberth et al. in Nat Clim Chang 4:17–22, 2014).
The importance of surface water quality in controlling the health of aquatic ecosystems, affectin... more The importance of surface water quality in controlling the health of aquatic ecosystems, affecting drinking water resources, and human health is increasingly recognized. Nutrients (mainly nitrogen and phosphorus) are essential for the life of animals and plants, but high concentrations cause many ecological problems (Carpenter et al. 1998; Li et al. 2011; Smith 1982; Sprague and Lorenz 2009).
This paper reports our research effort aiming to investigate the applicability of integrating a h... more This paper reports our research effort aiming to investigate the applicability of integrating a hydrological model and the Hydrological Predictions for the Environment (HYPE) model with a geographic information system (GIS) to examine the effect of land use change and climate change on stream-flows with the Kamo River basin (KRB) located in the central Honshu island, Japan as a case study. The goal of this study was to provide important information for understanding water discharge variations as a basis to guide water resource managers in environmental change decisions in this river basin. This goal was accomplished by two steps (i) comparing HYPE-generated hydrographs for various meteorological data from history to present at current land use (S1 and S2); and (ii) comparing HYPE-generated hydrographs for historical and current land use scenarios at current climate (S3 and S4). The calibration and validation results suggest that HYPE performs well in the case study site for daily simulations. The results of S1–S2 indicate that with the impact of climate change, the trend of annual and seasonal stream flows at the Kamo River Basin outlet would decrease. However, there is no evidence to indicate that the flood risk would be decreasing. The results of S3–S4 show that the conversion of forest, glass and agriculture (FGA) into urban area would induce high peak flows, a reduction in annual evaporation and an increase in annual surface runoff.
Evidence for climate change impacts on the hydro-climatology of Japan is plentiful. The objective... more Evidence for climate change impacts on the hydro-climatology of Japan is plentiful. The objective of the present study was to evaluate the impacts of possible future climate change scenarios on the hydro-climatology of the upper Ishikari River basin, Hokkaido, Japan. The Soil and Water Assessment Tool was set up, calibrated, and validated for the hydrological modeling of the study area. The Statistical DownScaling Model version 4.2 was used to downscale the large-scale Hadley Centre Climate Model 3 Global Circulation Model A2 and B2 scenarios data into finer scale resolution. After model calibration and testing of the downscaling procedure, the SDSM-downscaled climate outputs were used as an input to run the calibrated SWAT model for the three future periods: 2030s (2020–2039), 2060s (2050–2069), and 2090s (2080–2099). The period 1981–2000 was taken as the baseline period against which comparison was made. Results showed that the average annual maximum temperature might increase by 1.80 and 2.01, 3.41 and 3.12, and 5.69 and 3.76 °C, the average annual minimum temperature might increase by 1.41 and 1.49, 2.60 and 2.34, and 4.20 and 2.93 °C, and the average annual precipitation might decrease by 5.78 and 8.08, 10.18 and 12.89, and 17.92 and 11.23% in 2030s, 2060s, and 2090s for A2a and B2a emission scenarios, respectively. The annual mean streamflow may increase for the all three future periods except the 2090s under the A2a scenario. Among them, the largest increase is possibly observed in the 2030s for A2a scenario, up to approximately 7.56%. Uncertainties were found within the GCM, the downscaling method, and the hydrological model itself, which were probably enlarged because only one single GCM (HaDCM3) was used in this study.
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Papers by Kaoru Takara