Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Reasearch Centre for Astronomy and Earth Sciences Hungarian Academy  

Leaf area index (LAI) belongs among the catchment characteristics widely used in hydrological models but still associated with great uncertainties. In a mountain forest catchment, the leaf area affects retention and evapotranspiration loss, and it could be significantly modified by forestry practices. In this study, LAI in mature stands of Norway spruce (Picea abies) and European beech (Fagus sylvatica) was analysed in headwater catchments of the Jizera Mountains (Czech Republic) between 2012 and 2016. A comparison evaluation of LAI in harvested site with dominant herbaceous vegetation was taken into account by applying direct ground investigation what was compared with hemispherical canopy photography (Gap light analyser GLA-V2) and satellite remote sensing (Sentinel-2 mission). While the direct ground measurement includes only the foliage (leaves or needles), the Gap light analysis is affected by trunks and branches, and the remote sensing techniques by herbaceous understory. The results of the Gap light analyser underestimated the ground based LAI values by 52–76 per cent, and satellite interpretations by 29–73 per cent. The remote sensing is capable to provide effective information on the distribution of LAI within the time and space. However, in a catchment scale, the satellite detection underestimated average LAI values approx. by 42–62 per cent. Changes in the observed rainfall interception reflected well the LAI variation.

DOI： 10.15201/hungeobull.67.1.1

Scopus

researchmap

Language：Japanese   Publisher：Japan Society of Civil Engineers  

<p> It is required to evaluate climate change impacts on flood control and water utilization functions of dams after releasing MLIT vision for dam upgrading under operation. Up to now, however, there is no suitable evaluation methods to clarify those impacts, it is important to establish appropriate screening criteria in order to select high priority existing dams for upgrading. In this research, we firstly predicted changed in flow regime curves under climate change impact. Secondly, several criteria has been proposed to evaluate both changes in flood intensity and water shortage volume as well as available capacity for flood control and possibility for flexible dam operation. Based these evaluation criterias, we found that it is necessary to mitigate climate change in order to maintain necessary functions at about 90% dams.</p>

DOI： 10.2208/jscejhe.74.5_I_1333

CiNii Books

researchmap

Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;Freshwater discharge from watersheds is one of the important boundary conditions for coastal hydrodynamic simulations, but its available observations are very limited at small rivers. The present study developed a hydrological discharge and coastal hydrodynamic model with high resolution for Seto Inland Sea and its all river basins. Using this model, we evaluated freshwater discharge to the sea for the period of 2007&ndash;2015 and investigated impacts of small rivers on reproducibility of coastal hydrodynamic simulation. The hydrological simulation indicated that total annual amount of freshwater discharge to the sea was 53.0 km³/yr; 68% was from 21 major rivers and 32% was from small rivers. The coastal hydrodynamic simulation overestimated sea surface salinity if the freshwater discharge only from the major rivers was given; reproduced well if all rivers were considered.

DOI： 10.2208/kaigan.74.I_1135

CiNii Books

researchmap

Other Link： http://www.lib.kobe-u.ac.jp/handle_kernel/90006805

Language：Japanese   Publisher：Japan Society of Civil Engineers  

<p> A fundamental study was conducted to estimate effects of adaptation options for climate change based on impact assessment of river flow change on reservoir operation for water use. Current climate data (1979-2003) and future climate data (2075-2099) projected by MRI-AGCM3.2S were used as meteorological input. River discharges in both climates were respectively estimated from climate data by use of Hydro-BEAM, a cell concentrate type hydrological model, integrating operation of reservoirs for water supply and water intake in the target river basins. As a result of analysis for the Yoshino Rive basin, it was shown that the storage capacity of the Sameura Reservoir for water use would not be sufficient due to a decrease in river flow under the future climate. It was also shown thatn regulating water demands could be needed for adaptation in addition to reallocation of storage capacities of a multi-purpose reservoir.</p>

DOI： 10.2208/jscejhe.74.5_I_85

CiNii Books

researchmap

Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;A fundamental study on impact assessment of climate change on operation of reservoir systems and river discharges in Japanese river basins were conducted as a fundamental study in order to develop a method to operate reservoirs more effectively under the expected future climate condition. Current climate data (1979-2003) and future climate data (2075-2099) projected by MRI-AGCM3.2S, a high resolution AGCM developed by Meteorological Research Institute, were used as meteorological input. River discharges in both climates were respectively estimated from climate data by use of Hydro-BEAM, a cell concentrate type hydrological model, integrating operation of reservoirs for water supply and water intake in the target river basins. The assessment was conducted in the Yoshino River basin where droughts often occur, and the Mogami River basin where snow melting water contributes to river discharge significantly. The results suggested that the potential changes in river discharge that may increase a risk of drought in the future. The assessment also showed that the a shift in the snow melting period may not impact water use operation of multi-purpose reservoirs such as the Shirakawa Reservoir that has a seasonal regulation to lower the water use capacity in order to enlarge flood control capacity after the drawdown period.

DOI： 10.2208/jscejhe.74.I_115

CiNii Books

researchmap

Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;A method of real-time reservoir operation for water supply considering operational ensemble forecasts of precipitation was developed in this study. One-month and One-week Ensemble Foreacasts provided by Japan Meteorological Agency were considered as operational forecasts of precipitation. Ensemble stream-flow predictions for the coming one month were estimated by use of Hydro-BEAM, a distributed rainfall-runoff model, integrating predictions derived from the two operational forecasts of precipitation. The stochastic dynamic programming (SDP) and sampling SDP were considered to optimize reservoir operation considering ensemble streamflow prediction. The proposed method was applied to the simplified operation of the Sameura Reservoir in the Yoshino River basin in Japan, demonstrating the effectiveness to consider operational ensemble forecasts of precipitation in reservoir operation for water supply.

DOI： 10.2208/jscejhe.73.I_1315

J-GLOBAL

researchmap

researchmap

Language：Japanese  

CiNii Books

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPRINGER-VERLAG SINGAPORE PTE LTD  

DOI： 10.1007/978-981-287-615-7_23

Web of Science

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;In this study, we constructed a simulation model to simulate for future water demand by different sectors (agriculture, industry, and domestic) in each prefecture of Japan. We also estimated the future water resource of each prefecture based on the data of AMeDAS, the GCM (Global Climate Model), and statistical literatures. The water demand model was constructed by using published statistical data and information derived from the geographical information system (GIS). The model can estimate water demand by different sectors from year 2000 to 2050 (the simulation time step is 5 years) for different socioeconomic scenarios and with the introduction of water-saving technologies. The water demand for different scenarios is estimated by considering changes in population, economic situation, area of cultivated land, population with access to a water supply, water recycling in industrial processes, among other factors. We finally evaluated the gap between the water demand and supply by each prefecture. An understanding of future water demand and supply using this model could help in a re-evaluation of appropriate water use, thus avoiding water shortages as well as allowing for an examination of the influence on river flows.

DOI： 10.2208/jscejer.71.I_369

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.proenv.2015.07.036

researchmap

Language：Japanese  

In the big trend of shifting energy sources from nuclear and thermal power to renewable energy, hydropower generation has collected significant attention in Japan. In this research, focusing on 91 dams all over the Japan, it is shown how much potential it additionally generates only by changing maximum discharge Qmax, which is the setting of water volume used for power generation, of existing powered dams in Japan and how it changes by the effect of climate change. This study showed all the dams have potential to develop, and about 7% of increase is expected in total only by the simple operation change. It is, however, estimated that the generation will decrease by 11% in total in future by the effect of climate change. This situation can be improved by utilizing future potential of hydropower, and the results shows that the decrease ratio goes up till －6% in total, though it still remains negative. Whereas the generation of Hokkaido drastically increase about 20% in the future.

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2433/217278

Language：Japanese  

This study proposes an integrated model of basin-scaled hydrological and environmental dynamics including coastal water behavior in two dimensions. We conventionally have runoff, load transfer, water temperature, groundwater, sediment yield/transfer, chemical load yield/transfer, flooding/inundating, transient biomass, coastal water and hu1nan-activity effect models in space and time. These ones, nevertheless, were proposed at their appropriate scales, respectively. This research attempts to link them to each other at the common scale in considering the relationships among them. The model proposed herein is an integrated one based on the abovementioned ones with the mutual reactions. It can be proven that the integrated model is interpretively produced with compound effects corresponding to water-related dynamics at river basin scale.

CiNii Books

J-GLOBAL

researchmap

Language：Japanese  

DOI： 10.2208/jscejhe.70.I_1213

J-GLOBAL

researchmap

Language：Japanese   Publisher：The Society of Crop Science and Breeding in Kinki, Japan  

The contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (AR5) is discussed in this study. Representative Concentration Pathways (RCP) scenarios are used rather than Special Report on Emission Scenarios (SRES) in the AR5. In this report, it is stated that human influence likely has been the dominant factor in observed global warming since the mid-20th century. Although this evidence is the same as that previously reported, new opinions are also offered. For example, cumulative CO_2 emissions are expected to largely determine global mean surface warming by the late 21st century, and geoengineering methods that aim to deliberately alter the climate system may counter climate change. In this study, we introduce a water resource change projection study in a heavy-snow region where the climate change impacts are significant, and an impact evaluation study in the Mekong Delta, which is highly susceptible to rising sea levels and flooding.

DOI： 10.18964/jcr.59.0_49

CiNii Books

J-GLOBAL

researchmap

Language：Japanese  

Makio dam in the Kiso River is a multipurpose dam which generates hydroelectric power and supplies water to the Aichi Irrigation Project. Reservoir sedimentation increased in this Dam because of Nagano West Earthquake in 1984. It cost about 30 billion yen to recover active storage capacity in 1996 by excavating deposited sediments. In the future, flow regime is going to change due to global warming which will have another impact on water resources management. In this study, we assessed multiple effects of the several reservoir sedimentation and future in flow change by GCM model and distributed hydrological model (Hydro-BEAM). We evaluated economic effect in future (2093-2110) in terms of hydropower generation and water supply to the Aichi Irrigation Project. Regarding hydroelectric power generation, annual total generation can be almost maintained by modifying seasonal dam operation rule. Regardless of the sedimentation scenarios and flow-regime changes, annual total hydroelectric power generation can be maintained. However, water supply to the Aichi Irrigation Project will be seriously damaged due to a loss of active storage volume by reservoir sedimentation and changes in seasonal availability of discharge.

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2433/210045

Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;Global warming is a serious problem that cannot be avoided any longer. This problem has impacted on weather and climate. Therefore the snow (snowfall, snow accumulation and snowmelt) will be changed greatly in the future compared with the current situation.<br>&nbsp;In this study, we analyzed the impact on the ski business due to the changes of snow amount by the global warming. Firstly, we estimated by regression analysis the relationship between the snow amount and the number of visitors of the ski areas in the Toyama Prefecture. Secondly, the data of snowfall in current and future were created by using the observed data and data from Soil Vegetation Atmosphere Transfer model and Global Climate Model. Thirdly, by using the data of snowfall in the future under global warming as well as the relationship of the snow amount and the number of visitors, we calculated the effect of snowfall on the business income and the number of visitors in the future. Finally, we surveyed to the ski area owners for adaptation methods against the global warming.

DOI： 10.2208/jscejer.70.I_21

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

To evaluate the impacts of climate change on river discharge, we applied a hydrological simulation to several major river basins in Japan, using a super-high-resolution atmospheric general circulation model (AGCM) with a horizontal resolution of about 20 km that was developed by the Meteorological Research Institute (MRI) of the Japan Meteorological Agency. For our analysis, we used two AGCM datasets corresponding to the current climate (1980-1999) and future climate (2080-2099) based on the sea surface temperature ensemble projected by the Coupled Model Intercomparison Project phase 3, assuming the A1B scenario of the Intergovernmental Panel on Climate Change Special Report on Emission Scenarios. River discharge was estimated using a distributed hydrological model that was calibrated in advance with observed river discharge. We investigated the impact of climate change on river discharge by comparing hydrological simulations of current and future climate conditions. The results showed that the latest version of the AGCM (MRI-AGCM3.2S) performs better hydrological simulations than the previous version (MRI-AGCM3.1S). Even if the amount of precipitation does not change greatly in the future, river discharges will change significantly as air temperature rises, owing to increased rainfall, decreased snowmelt, and increased evapotranspiration. The impact of climate change on river discharge will become more significant in northern Japan, especially in the Tohoku and Hokuriku regions. Our results imply that the increase in air temperature will have important consequences on the hydrological cycle, particularly in regions where the water supply is currently domi\nated by snowmelt. Copyright (c) 2013 John Wiley & Sons, Ltd.

DOI： 10.1002/hyp.9828

Web of Science

researchmap

Language：English  

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

researchmap

Language：Japanese  

CiNii Books

J-GLOBAL

researchmap

Language：Japanese  

DOI： 10.2208/kaigan.69.I_1286

J-GLOBAL

researchmap

J-GLOBAL

researchmap

Language：English   Publishing type：Part of collection (book)   Publisher：John Wiley and Sons  

DOI： 10.1002/9781118470596.ch4

Scopus

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHINESE GEOSCIENCE UNION  

The impact of climate change on river discharge was assessed by hydrological simulations for several major river basins in Japan using the latest version of a super-high-resolution atmospheric general circulation model (AGCM) with a horizontal resolution of about 20 km. Projections were made using two different datasets, one representing the present climate (1980 - 1999) and the other representing the end of the 21st century (2080 - 2099) assuming the SRES AIB scenario. River discharge was estimated by a distributed hydrological model calibrated against observed river discharge in advance. The results showed that even if the amount of precipitation does not change much in the future, river discharge will change significantly because of the increase in rainfall, decrease in snowmelt, and increase in evapotranspiration with higher air temperature. The impact of climate. change on river discharge will be more significant in the northern part of Japan, especially in the Tohoku and Hokuriku regions. In these regions, the monthly average river discharge at the end of the 21st century was projected to be more than 200% higher in February and approximately 50 - 60% lower in May compared with the present flow. These results imply that the increase in air temperature has important consequences for the hydrological cycle, particularly in regions where the water supply is currently dominated by snowmelt.

DOI： 10.3319/TAO.2012.05.03.02(WMH)

Web of Science

researchmap

Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;The outputs of 29 Global Climate Model (GCM) are adjusted to per nearly 80km square called primary area partition for the Standard Grid Square. The datasets are used to analyze monthly precipitation and temperature in seven typical basins in Japan. Evaluated with AMeDAS observation, MRI-AGCM outputs have high resolution and they are proved to have better reproducibility. Regarding GCM outputs belonging to CMIP3 with coarse resolution of more than 100km, the reproducibility of each individual GCM is worse but the multi-GCM ensemble shows improvement of reproducibility. At the same time, there are no clear differences between CMP3 and MRI-AGCM outputs as for the change calculated from present and future climate predictions. This shows that high reproducibility would not lead directly to reducing uncertainty of estimating future climate change. On the basis of these results, practical usage of GCM outputs with observation data is considered for hydrological analysis.

DOI： 10.2208/jscejhe.68.125

researchmap

Language：Japanese  

For the purpose of an integrated watershed environment management, a coupled river runoff and ocean circulation model is developed. Climate change impact on the hydrologic environment of Ise Bay is assessed by the model. Future climate change of rain fall amount and air temperature from 15 CMIP3 models are used as an atmospheric boundary conditions, and climate change of river discharge and water temperature from Hydro-BEAM prediction are also used as a river mouth boundary condition. Future SST in Ise Bay increases by about 3℃ in August, while 2℃ in February. Coastal areas are more strongly influenced.

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2433/181509

Language：Japanese  

We performed Internet questionary survey subject to residents in Toyama and grasped the image for the climate change and examined a reporting policy to enlighten the consciousness of the citizen for the climate change. The persons who feel a climate change at the present tend to feel the additional changes in the future. It is important to show the monitoring results of climate change for a citizen and promote the understanding for the climate change that had already occurred. It has been shown that general images for the climate change promote to understand the need of the mitigation, and that it is important to explain about the climate change that might occur in the future even if it did not occur at the present in order to have people recognize widely the need of the adaptation.

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2433/181508

Language：Japanese   Publisher：Japan Society of Civil Engineers  

&nbsp;A coupled river discharge and ocean circulation model was developed, which aimed for the effective tool for the integrated environment management of the watershed area including rivers and ocean. The model consists of the distributed hydrological model, the unsteady flow model near river mouse, the ocean circulation model and the advective diffusion model. These four models are connected each other through the boundary conditions. We applied the model to the heavy rainfall case around Kiso-sansen rivers and Ise Bay during April 2003. It was concluded that the river water level calculation corresponded well to the observation, and the calculated suspended sediment distribution was qualitatively conincident with the MODIS satellite observation.

DOI： 10.2208/jscejoe.68.I_1001

J-GLOBAL

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

&emsp;In the field of hydrology and water resources, river planning is performed on the basis of observation data. The determination of the long-term effect of climate change for the purpose of risk management strongly depends on the performance of the climate model used. Therefore, it is necessary to consider the reproducibility of Japanese climatology simulated by the climate models. In this study, the reproducibility of the present climate simulation over Japanese land area was tested by analyzing surface meteorological elements (e.g., precipitation) using the Coupled Model Intercomparison Project phase 3 (CMIP3) multi-model dataset for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report. The result shows that the variability of precipitation and snowfall in each climate model is larger and that some models do not represent the patterns of seasonal change at all. We filtered the climate models by using data from the Japanese 25-year Reanalysis (JRA-25) and weather observation stations as a standard, and reduced the uncertainty of the prediction.

DOI： 10.3178/jjshwr.24.280

CiNii Books

J-GLOBAL

researchmap

Language：English   Publisher：Japan Society of Civil Engineers  

GCM (Global Climate Model) outputs differ corresponding to models used, SRES (Special Report on Emissions Scenarios), and multiple realizations with variation in the initial conditions. The Climate Change Information Database was developed in order to compare various GCM dataset on any area of primary mesh (approximately 80 km x 80 km) for surface meteorological elements such as precipitation and temperature. The database is open to the public through the website, and users can display distribution map and reference chart with simple operation through a web browser. The database will make it easier to understand overview of the climate change simulated by GCM and impact assessment of global warming.

DOI： 10.2208/kaigan.67.I_1211

CiNii Books

J-GLOBAL

researchmap

Language：Japanese  

The outputs of 17 Global Climate Model (GCM) from CMIP3 and 4 GCM from MRI-AGCM with 20km/60km grid are used to analyze precipitation characteristics in Japan for reproducibility of present climate and future climate change. The target characteristics are monthly precipitation, standard deviation of monthly precipitation, top 2% daily precipitation and non-precipitation days defined as daily precipitation < 1mm during 20 years. About all characteristics, the reproducibility of present climate with MRI-AGCM is better. Though the future change ratio, calculated from present and future climate predictions, vary in each GCM, there are no clear differences between CMIP3 and MRI-AGM.

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2433/161822

Language：Japanese  

Impact assessment of river outflow on Ise Bay was investigated by using the integrated water environment model. The model consists of the distributed Hydrological River Basin Environment Assessment Model (Hydro-BEAM), RIAM ocean circulation model (RIAMOM), and the advective diffusion model for Ise Bay. River outflow, water temperature and sediment transport are nested at the river mouse, and JCOPE2 re-analysis data are used as an open sea boundary condition. Simulated sediment transport on 27/Apr/2003 was compared with the satellite image by the Aqua MODIS sensor.

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2433/161824

Language：Japanese  

In the Kiso river system, the river flow is controlled by the many multi-purpose reservoirs operation located in the upstream of the basin. Thus, in order to simulate river flow more realistically, we upgraded our distributed hydrological model by considering actual reservoirs operation and water withdrawal from the river channel. The results indicate that our new model shows better performance than the previous one. However, we also found that further improvement is needed to the maintenance flow modeling for more realistic river flow simulation.

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2433/161823

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

The Yellow River, the main source of water for the North and Northwest China, showed a marked decrease in runoff during the 1990s compared to that in the 1980s. Since the basin is extensive, covering many different climatic zones with various land uses, the hydrological processes are very complex. It is necessary to develop and verify a detailed water budget in order to understand changes in the hydrological processes within the basin. In this paper, we describe a hydrological model that considers five categories of land use. The calibration and verification of the model were carried out at two independent watersheds (Tangnaihai, 120 000 km(2) and Lushi, 6400 km(2)). The results from the model represent the hydrographs and annual runoffs at two gauge stations over a relatively long-term period (18 years at Tangnaihai and 21 years at Lushi). The model was applied to other watersheds of the Yellow River basin above Huayuankou station, and water budget components in each region were analysed. The results indicate only a small change in evapotranspiration, but a marked decrease in precipitation, which was significant in all of the analysed areas except the Lanzhou-Toudaoguai inter-watershed area. Water use for agricultural irrigation was stable throughout the entire simulation period. A numerical experiment of water conservation for the whole basin above Huayuankou station demonstrated that if the number of irrigation days was reduced by 20, 40 or 60%, the amount of water used could be reduced by 26.6, 52.1 or 80.7%, compared to the current situation. Copyright (C) 2010 John Wiley & Sons, Ltd.

DOI： 10.1002/hyp.7556

Web of Science

researchmap

Language：Japanese  

To clarify the hydrological impact of climate change on water resources management and adaptation measures for river disaster prevention in a regional scale, a super high resolution AGCM20 and CMIP3 multi model dataset are applied to the Kiso three rivers basin as an input data for a distributed hydrological model (Hydro-BEAM) with storage reservoir. The results shows that the uncertainties of the future projection caused by a relatively coarse resolution current conventional GCMs can be decreased significantly by a simple multi-model ensemble approach applied in this study.

CiNii Books

J-GLOBAL

researchmap

Language：Japanese  

Limited individuals can handle the outputs of Global Climate Model (GCM) because of massiveness and complexity of the data, while impact assessments by the climate change heavily depend on the experiment results of GCM. In this study, surface meteorological elements (precipitation, temperature, etc.) in GCM outputs are collected and compiled to construct the database by primary area partition of grid square method (approximately 80km x 80km). The database makes it possible to evaluate the climate change in arbitrary area in Japan simulated by multiple GCMs. The database has observation values and reanalysis data, in order to verify the reproducibility of present climate. Furthermore, the website is developed for the public to access the data of climate change.

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2433/151018

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

The increases in water demand associated with rapid socio-economic development led to water shortage in the northern part of China, such as in the Yellow River basin. Nowadays, the use of agriculture water is beginning to be restrained by the increase in new water uses, such as industrial water and domestic water; and by rapid pace of industrialization and urbanization. However, it is significant to secure agriculture water to meet the increasing and diverse food demand of its growing population. Subsequently, the Chinese government plays a central role in the efforts to overcome the water shortage, such as in the &lsquo;South to North Water Transfer Projects. In order to resolve the issue of such water shortage, it is important to understand how water can be used in the most physically and economically efficient way, and the extent on how much water use can be reduced in what regions. The effective and rational use of agriculture water is necessary if the country is to achieve a sustainable agricultural production. From this viewpoint, we applied DEA (Data Envelopment Analysis) techniques to a provincial level dataset to estimate the efficiency of agricultural water use in China. In addition, we compared and examined the differences of efficiencies among the main river basins which are created by the administrative unit on a province level. We also identified determinant factors affecting the efficiencies using the Tobit model.

DOI： 10.3178/jjshwr.22.356

CiNii Books

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER GEOPHYSICAL UNION  

The headwater catchments of the Yellow River Basin are of great importance for the whole basin in terms of water resources, and streamflow from these catchments has decreased in the last decades. The concept of climate elasticity was used to assess the impacts of climate and land surface change on the streamflow. Results show that for the period 1960-2000 the elasticity of streamflow in relation to precipitation and potential evapotranspiration are 2.10 and -1.04, respectively, indicating that streamflow is more sensitive to precipitation than to potential evapotranspiration. However, land use change played a more important role than climate in reducing streamflow in the 1990s. It is estimated that land use change is responsible for more than 70% of the streamflow reduction in the 1990s, while climate change contributed to less than 30% of the reduction. The precipitation elasticity appears to have an inverse relationship with the runoff coefficient but a positive relationship with the aridity index, showing that the drier the catchment, the more sensitive the streamflow with respect to precipitation change.

DOI： 10.1029/2007WR006665

Web of Science

researchmap

Publishing type：Research paper (international conference proceedings)  

To clarify the influences of human activities on fresh water resources, the long-term (1960-2000) water balance of the Yellow River Basin (YRB) was analyzed using a semi-distributed hydrological model. To estimate the impact of the major anthropogenic factors, the following three sub-models (1) land-use change, (2) reservoir operation and (3) irrigation water use were applied. The model showed the impacts of soil water conservation in the Loess Plateau, large reservoir operation in the upper reach, and the deference of irrigation water use between upper and lower reaches quantitatively. The model developed in this study will contribute to the Integrated Water Resources Management (IWRM) in many countries and regions which are suffered by the various human activities. © 2009 Taylor & Francis Group.

Scopus

researchmap

Publishing type：Research paper (international conference proceedings)  

China has expanded its food supply in order to meet the increasing food demand for its growing population. The agricultural production in the Yellow River Basin, one of the important agricultural production areas of China, has increased in recent years. However, water shortages have become severe, and excessive use of water in agriculture may worsen this problem. Thus the effective use of water resources is essential in this area. In this study, we estimated agricultural Water Use Efficiency (WUE) of year 2000 by using hydrological model, agricultural field data and grain yield statistics data. The results suggest that further improvement of agricultural WUE in the upstream is necessary toward sustainable agricultural production. © 2009 Taylor & Francis Group.

Scopus

researchmap

Language：Japanese  

The accuracy of the current climate simulations of Japan was tested, using the CMIP3 multi-model dataset and focusing on major hydro-meteorological elements. The study analyzed the area surrounding Japan including the territorial waters, by dividing it into five regions (a land region and four ocean regions), as the rough grids in the multi-model dataset did not well represent the Japanese terrain. The result obtained in this study showed that the accuracy of the outcomes from each model depends on the meteorological element tested. In particular, some models were not accurate in simulating precipitation, not only in regard to the distribution by roughly divided area, but also in seasonal change. It indicates significance of confirming accuracy in using the CMIP3 multi-model dataset (e.g. downscaling for hydrologic applications).

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2433/129360

Language：Japanese  

A coupled river discharge and ocean circulation model was developed, in order to study the impact of river outflow on water environment of Tokyo Bay. A distributed Hydrological River Basin Environment Assessment Model (Hydro-BEAM) and RIAM ocean circulation model (RIAMOM) are connected at the river mouse as boundary conditions of river outflow. River outflow from Arakawa, Edogawa, Tamagawa and Sagamigawa are concerned. Case studies for typhoon are simulated and the model results are verified with the observation of river current, ocean current, sea surface temperature and salinity. A result from case study simulation shows that fresh waters from river outflow are distributed in the north-west part of Tokyo Bay.

CiNii Books

J-GLOBAL

researchmap

Language：Japanese  

In order to clarify the hydrological impacts of climate change in the Kiso Three River basin, a super-high resolution atmospheric general circulation model (MRI-AGCM20) based on IPCC SRES-AR4-A1B scenario were used as input parameter for a distributed Hydrological River Basin Environment Assessment Model (Hydro-BEAM). The results obtained in this study showed that long-term trend of air temperature and precipitation estimated by the non-parametric Mann-Kendall test and change of future river flow regimes by the flow duration curves (FDCs).

CiNii Books

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

To analyse the long-term water balance of the Yellow River basin, a new hydrological model was developed and applied to the source area of the basin. The analysis involved 41 years (1960-2000) of daily observation data from 16 meteorological stations. The model is composed of the following three sub-models: a heat balance model, a runoff formation model and a river-routing network model. To understand the heat and water balances more precisely, the original model was modified as follows. First, the land surface was classified into five types (bare, grassland, forest, irrigation area and water surface) using a high-resolution land-use map. Potential evaporation was then calculated using land-surface temperatures estimated by the heat balance model. The maximum evapotranspiration of each land surface was calculated from potential evaporation using functions of the leaf area index (LAI). Finally, actual evapotranspiration was estimated by regulating the maximum evapotranspiration using functions of soil moisture content. The river discharge estimated by the model agreed well with the observed data in most years. However, relatively large errors, which may have been caused by the overestimation of surface flow, appeared in some summer periods. The rapid decrease of river discharge in recent years in the source area of the Yellow River basin depended primarily on the decrease in precipitation. Furthermore, the results suggested that the long-term water balance in the source area of the Yellow River basin is influenced by land-use changes. Copyright (C) 2007 John Wiley & Sons, Ltd.

DOI： 10.1002/hyp.6730

Web of Science

researchmap

Language：Japanese  

This study presents a newly developed method for estimation of hydrological distributions in space and time based on observed data. To extend spatial estimates into spatiotemporal ones, a conversion parameter of temporal-distance is newly defined and introduced into the kriging equations using the trend and covariance functions. This parameter equivalently converts a temporal gap into a spatial distance in the time-related terms of those functions. In topological space in one dimension, the above approach is most effective and helpful to krig a hydrological distribution. It can be shown that the developed method of kriging estimation in space and time with a conversion parameter is useful and applicable to a spatiotemporal interpolation through the numerical tests.

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2433/129269

Publishing type：Research paper (international conference proceedings)  

To clarify the influences of climate change and human activities on river discharge, the long-term (1960-2000) water balance in the middle reaches of the Yellow River basin was analysed using a hydrological model. To estimate evapotranspiration from various land-use types, a high resolution land surface classification map in 2000 was used. When we applied the same land-use parameter of 2000 during the past 40 years, the results estimated by the model underestimated the river discharge. Then we modified the parameter to decrease evapotranspiration by reducing the vegetation cover. After that, the observed discharge was reasonably captured by the model. Consequently it was found that the massive land-use change and rapid decrease of available water resources in the middle reaches of the Yellow River basin will affect the water shortage in the lower reaches of the Yellow River basin. Copyright © 2007 IAHS Press.

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

This study presents the results of 2 years combined field measurements of water vapor exchange with the atmosphere and simplified model calculations at Lambir Hills National Park, Sarawak, Malaysia (4degrees12'N, 114degrees02'E). The study site was located in a lowland mixed dipterocarp forest, a major type of Bornean tropical rainforest, where there is no clear seasonality in environmental factors such as radiation, temperature, vapor pressure deficits and precipitation; instead, unpredictable dry spells often occur throughout the year. Modified [Priestley, C.H.B., Taylor, R.J. (1972). On the assessment of surface heat flux and evaporation using large-scale parameters, Mon. Weather Rev. 100, pp. 81-92] and equilibrium evaporation expressions enabled us to understand further the environmental control of water vapor exchanges with the atmosphere and to produce a complete gap-filled data set of the hydrologic fluxes within this environment. The equilibrium evaporation from a well-watered surface sufficiently reproduced the transpiration rate (T-r); any discrepancies between the equilibrium and actual evaporation rates were caused by unpredictable intra-annual dry spells, which reduced transpiration. There were some discrepancies during the study period because of exceptional dry sequences, but in normal years the annual transpiration rate can be obtained from the equilibrium evaporation expression. The estimated annual T-r (1193.1 mm) and evapotranspiration (1545.0 mm) rates were nearly identical to the highest values reported for some humid tropical forests. Although, there were exceptional dry sequences during the study period, the annual average fraction of available energy dissipated by T-r at this site (0.69) was almost the same as the medium value between the dry and wet seasons in Amazonian tropical forests. This implies that the annual dynamics of the latent heat flux for this tropical rainforest are under more humid conditions than those of other tropical rainforests. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.agrformet.2004.08.006

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

CiNii Books

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

We refined a previous auto measurement system for CO<SUB>2</SUB> concentration profile (Xu <I>et al</I>., 1999) and reported the detailed information for reproducing this system. Also, as a management case of this system, we demonstrated an example of observation results in a Bornean tropical rainforest, Malaysia ; a diurnal change of the storage flux, the above-canopy flux, the net ecosystem exchange and the CO<SUB>2</SUB> concentration profile within a canopy.

DOI： 10.3178/jjshwr.17.648

CiNii Books

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS LTD  

The effects of rainfall conditions and the morphological characteristics of leaves on the moisture dynamics of litter layers were investigated. Maximum water storage capacity and interception storage capacity under various rainfall conditions were evaluated for two contrasting litter :types: a needle-leaf type, represented by Cryptomeria japonica leaves: and a broad-leaf type, represented by Lithocarpus edulis leaves. An artificial rainfall simulator was applied to measure each litter type's interception storage capacity under various rainfall intensities. Our results indicated that (1) the maximum water storage capacity of each litter layer was proportional to the litter mass (kg/m(2)) regardless of layer thickness, (2) the litter interception storage capacity increased with rainfall intensity in the range of realistic rainfall conditions (under 50 mm/h); (3) the broad-leaf litter of L. edulis intercepted more rainwater than the needle-leaf litter of C. japonica; and (4) the rainwater moved laterally in the litter layer of L. edulis whereas it moved directly down in the litter layer of C. japonica. These results show that not only the litter mass but also the rainfall conditions and leaf shapes are important in evaluating the moisture dynamics of litter layers. Copyright (C) 2004 John Wiley Sons, Ltd.

DOI： 10.1002/hyp.5746

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Tropical rainforests are among the most important biomes in terms of annual primary productivity and water cycling, However, the materials-exchange properties of Southeast Asian forests in their significant functions are less studied. We investigate key factors controlling materials-exchange, such as canopy (g,) and aerodynamic conductance (g.) and the decoupling coefficient (n) in an intact lowland mixed dipterocarp forest in Sarawak, Borneo. We operated an eddy covariance system above the canopy to measure canopy transpiration rate (E,) using an 80-m-tall canopy crane, and made concurrent meteorological measurements. In this region, solar radiation and air temperature have small seasonal variations, and annual rainfall is distributed evenly throughout the year, with some unpredictable intra-annual dry spells. We define three specific periods A, B and C as medium dry, heavy dry and wet periods, respectively, for analyses of the environmental control on E, according to their dryness level. The mean daily E, g, and D were higher in the wet period C than in the dry periods A and B. Also, each g, in its diurnal variation was much higher in the wet period C than in the dry periods A and B, where diurnal variations of g(c) were almost the same. Both the value of g, and its sensitivity to environmental variables were higher in the wet period C than in the dry periods A and B. The peak of n was higher in the wet period C than in the dry periods A and B because of a higher value of gc in period C. However, the higher values of gc in the wet period C did not cause a higher E, compared to in the dry periods A and B. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jhydrol.2003.10.002

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER GEOPHYSICAL UNION  

Southeastern Asian tropical rain forests are among the most important biomes in terms of annual productivity and water cycling. How their hydrologic budgets are altered by projected shifts in precipitation is examined using a combination of field measurements, global climate model (GCM) simulation output, and a simplified hydrologic model. The simplified hydrologic model is developed with its primary forcing term being rainfall statistics. A main novelty in this analysis is that the effects of increased (or decreased) precipitation on increased (or decreased) cloud cover and hence evapotranspiration is explicitly considered. The model is validated against field measurements conducted in a tropical rain forest in Sarawak, Malaysia. It is demonstrated that the model reproduces the probability density function of soil moisture content (s), transpiration (T(r)), interception (I(c)), and leakage loss (Q). On the basis of this model and projected shifts in precipitation statistics by GCM the probability distribution of Ic, Q and, to a lesser extent, s varied appreciably at seasonal timescales. The probability distribution of Tr was least impacted by projected shifts in precipitation.

DOI： 10.1029/2003WR002226

Web of Science

researchmap

Language：English   Publisher：Kyushu University  

CiNii Books

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

A simple model to evaluate litter interception losses in the plantation stands of <I>Cryptomeria japonica</I> and <I>Lithocarpus edulis</I> were developed. We applied this model to simulate the litter interception and evaporation rates under the different rainfall conditions and different shapes of the litter layer. Model parameters were estimated from field data using microlysimeter at each stand. The litter interceptions under various rainfall conditions were estimated using throughfall data. Evaporation rates from the litter layer during the dry periods were estimated by the relative water content of the litter layer. The estimated annual litter interception loss of <I>C. japonica</I> stand was 5.1&sim;11.5% of throughfall, and that of <I>L. edulis</I> stand was 9.5&sim;18.0% of throughfall. These results suggest that the litter interception process has a significant role in the forest hydrological cycles.

DOI： 10.3178/jjshwr.16.640

CiNii Books

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

The characteristics of throughfall of two forest stands with contrastive canopy structures were evaluated. Gross precipitation partitioning into throughfall in the experimental plantation stand of <I>Cryptomeria japonica</I> (ever-green coniferous tree) and that of <I>Lithocarpus edulis</I> (ever-green broad leaved tree) are studied. In order to compensate the effect of spatial variability of throughfall on the forest floor, the data of 3 tipping bucket raingauges were calibrated by the data of 25 or 30 fixed position funnel type raingauges. Spatial variability of throughfall in the <I>C. japonica</I> stand was larger than that in the <I>L. edulis</I> stand. The average ratio of throughfall to gross precipitation of <I>C. japonica</I> stand (0.64) was larger than the ratio of <I>L. edulis</I> (0.37) . In the L. edulis stand, throughfall started after only 0.9&sim;1.6mm of rain fallen, but it started after 1.9&sim;4.0mm of rain fallen in the <I>C. japonica</I> stand. These results suggested that LAI and canopy openness cannot fully explain the characteristics of throughfall and additional information, e.g. canopy structure (morphological factors), are needed.

DOI： 10.3178/jjshwr.16.605

CiNii Books

researchmap

Language：Japanese   Publisher：Kyushu University  

A numerical model to evaluate the effect of forest floor moisture dynamics in the Cryptomeria japonica and Lithocarpus edulis plantation stand was developed. This model enabled to simulate the litter interception and evaporation rate under the different rainfall conditions and different accumulation structures of the litter layer. To estimate the litter interception characteristics under the various rainfall conditions, two model parameters, S_max(Maximum water storage capacity) and L_i(Interception storage capacity under the rainfall conditions), were estimated by the laboratory experiments. Evaporation rates from the litter layer during the dry periods were estimated by the lysimeter observations conducted in each stand. The result of model simulation showed good agreement with the field observation and also indicated that hydrological significance of the litter interception process.

DOI： 10.15017/14843

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2324/14843

Language：Japanese   Publisher：Kyushu University  

To estimate annual canopy interception loss, observations of gross rainfall, throughfall and stemflow were made in mature Lithocarpus edulis Nakai stand at the Kyushu University Forests in Fukuoka prefecture from 11 July 2000 to 10 July 2001. To obtain continuous long-term dataset, rainfall measurement were conducted by plural tipping bucket raingages. Due to large spatial variability, throughfall data obtained by tipping bucket raingages which were calibrated by manual measurements with 36 storage type raingages. The results showed that the amount of annual gross rainfall was 1539.9mm, whereas throughfall and stemflow were 457.0mm (29.7% of gross rainfall) and 779.3mm (50.2%of gross rainfall) respectively. These results clearly showed that the effect of throughfall was relatively small compared to that of stemflow in this stand. Consequently, estimated annual canopy interception loss was 309.6mm (20.1%of gross rainfall) in this study.

DOI： 10.15017/14834

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2324/14834

researchmap

Language：Japanese   Publisher：Japanese Forestry Society  

In order to understand the mechanism of evaporation from a forest floor (EFF), EFF was measured as the sum of evaporation from the litter layer (ELL) plus evaporation from the mineral soil (EMS). A microlysimeter was used to measure the amount of evaporation from each part to estimate the covering effect of the litter layer. The results were as follows: (1) ELL varied according to the thickness of the litter layer when it was saturated, and was regulated by residual water in the litter layer when it was unsaturated. (2) The litter layer decreased EMS in proportion to the thickness of the litter layer. At an early stage in the experimental period, it became apparent that it was impossible to estimate the effect of cover with a litter layer, which was defined by Tamai and Hattori (1994). (3) The thickness of the litter layer had no significant effect on the EFF when it was saturated.

DOI： 10.11519/jjfs1953.81.3_250

CiNii Books

J-GLOBAL

researchmap

Other Link： https://agriknowledge.affrc.go.jp/RN/2010592487

Language：Japanese   Publisher：Kyushu University  

In order to make clear the processes of changes in rainwater chemistry through tree crown, volume of water, pH value, concentration and deposition of dissolved ions for rainfall, throughfall and stem flow were measured from July 1995 until June 1996. The experimental site was located in the Kyushu University Forests in Sasaguri, Fukuoka prefecture. The observed species were Sugi (Cryptomeria japonica D. Don) and Matebashii (Pasania ediulis Makino). The amount of stem flow was less than throughfall for C. japonica, but greater than throughfall for P. ediulis. The obtained value of stem flow for P. ediulis was 81% of total rainfall. This value is quite large compared with results of other studies. Concentration of dissolved ions for stem flow was higher than for throughfall for C. japonica, but lower than for throughfall for P. ediulis. However, deposition of dissolved ions for stem flow was less than for throughlall for C. japonica, but greater than for throughfall for ediulis. In addition, the origin of deposition of dissolved ions, dry deposition and leaching were greater than wet deposition for C. japonica, but wet deposition was greater than dry deposition and leaching for P. ediulis. These results indicate that distribution of dissolved ions of rainwater passing through tree crown depends on tree species and crown structure, due to their influence on rainwater distribution, adhesion of dry deposition and leaching rate.

DOI： 10.15017/10933

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2324/10933

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

Language：Japanese   Publisher：建設技術研究所国土文化研究所  

CiNii Books

CiNii Research

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

Language：Japanese   Publisher：土木学会  

CiNii Books

CiNii Research

researchmap

Language：Japanese  

CiNii Books

researchmap

J-GLOBAL

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

本研究は、小型UAVを利用して樹冠の画像を撮影し、SfM-MVSソフト（PhotoScan Professional Ver.1.3、Agisoft社）等を用いて、二つの森林水文試験地で、樹冠・樹形形状の解析を行った。信楽試験地の林内観測のプロットの落葉・常緑林混交林のうっ閉率は、着葉期91%と落葉期27%と算定された。また、杭瀬試験地のロットのスギ林のうっ閉率は74 %となったプロットに含まれる立木の樹冠投影面積は、4.7 m&lt;sup&gt;2&lt;/sup&gt;から20.2 m&lt;sup&gt;2&lt;/sup&gt;の範囲で、平均値は10.6 m&lt;sup&gt;2&lt;/sup&gt;であった。

DOI： 10.11520/jshwr.31.0_218

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

DOI： 10.11520/jshwr.31.0_112

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

2008年8月から白神山地核心・緩衝地域に隣接する原生的なブナの割合が高い森林内(北緯40度33分56秒、東経140度7分40秒)で微気象観測タワー(以下、単にタワー)を用いた総合気象・乱流観測が継続されている。山地の森林は水源涵養の役割を期待されているが、ブナはリターが豊富なため特にその能力が高いので、以前よりタワーでの観測から白神サイトの水循環の全般的な傾向を見出す研究が行われてきた(石田,2012)。しかし、年毎の蒸発散量の違いをもたらす要因については明らかにされていない。そこで、本研究では白神山地ブナ林における水循環の特徴を明らかにすべく、特に蒸発散に焦点をあてて、その量の影響要因を明らかにすることを目的とする。観測に用いたタワーの全高は34mで、タワーには一般気象および熱・水・CO2フラックスの測定のための機材が取り付けられている。対象期間は2012年～2016年で、蒸発散量は樹高上で測定されている風速と水蒸気密度の乱流データを使用し、渦相関法により求めた。また、現地の気象データを使い、ポテンシャル蒸発量&lt;i&gt;E&lt;sub&gt;p&lt;/sub&gt;&lt;/i&gt; (近藤・徐, 1997)も日単位で求めた。&lt;i&gt;E&lt;sub&gt;p&lt;/sub&gt;&lt;/i&gt;の定義は湿った標準面からの蒸発散量である。これと実蒸発散量&lt;i&gt;E&lt;/i&gt;を比べることで水分ストレスや蒸散量の大小を判断することができる。渦相関法のデータは品質チェックを行い、良質と判断された日の蒸発散量&lt;i&gt;E&lt;/i&gt;と&lt;i&gt;E&lt;sub&gt;p&lt;/sub&gt;&lt;/i&gt;との比を月ごとに求め、不良データの場合は&lt;i&gt;E&lt;sub&gt;p&lt;/sub&gt;&lt;/i&gt;より蒸発散量&lt;i&gt;E&lt;/i&gt;の推定を行った。2012年～2016年のこれらの値と降水量Prについて月積算値と年間積算値を求めた。結果として対象期間の年平均降水量は2808mm、年平均蒸発散量は604mmであった。年間で降水は約20%、蒸発散に分配されている。2013年は雪解けが遅く蒸発散量にも影響を与えた。2013年の蒸発散量は556mmで平均を下回っており、年間を通じて蒸発散量が他の年よりも小さかった。これは雪融けの遅れがブナのフェノロジーに大きく影響を及ぼし、蒸発散量にも影響を与えたと言える。これは、&lt;i&gt;E&lt;/i&gt;/&lt;i&gt;E&lt;/i&gt;&lt;i&gt;p&lt;/i&gt;の値が小さいことにも現れているようにみえる。逆に雪融けが5年間の中で最も早かった2015年は蒸発散量が713mmと平均値を上回っている。これらから、白神サイトでは、積雪はブナのフェノロジーに大きな影響を与え、ひいては、蒸発散量や&lt;i&gt;E&lt;/i&gt;/&lt;i&gt;E&lt;/i&gt;&lt;i&gt;p&lt;/i&gt;の変化を支配する一因になると考えられる。

DOI： 10.11520/jshwr.31.0_142

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

In order to clarify the water balance in the forest area, the annual amount of canopy interception in the Sugi plantation forest was estimated. It was found that the estimation formula in consideration of the rainfall intensity and the evaporation intensity is better in the reproducibility than the regression expression using only the simple rainfall amount. Furturemore, the evaporation coefficient during the rainfall for each rainfall event was roughly agrees with the value of LAI and was proportional to the rainfall intensities.

DOI： 10.11520/jshwr.31.0_224

researchmap

Language：English   Publishing type：Research paper, summary (international conference)  

researchmap

Language：English   Publishing type：Article, review, commentary, editorial, etc. (international conference proceedings)  

researchmap

Language：English   Publishing type：Article, review, commentary, editorial, etc. (international conference proceedings)  

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

DOI： 10.11520/jshwr.30.0_105

researchmap

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

Snow depth distribution in the Todori river basin was estimated by using simple snow density model for the input variables of the distributed hydrological model. The results obtained in this study showed reasonable value of monthly snow depth distribution of the Tedori river basin. However, for the better estimation, we found that the improvement of the model parameters are needed. <br>

DOI： 10.11520/jshwr.29.0_81

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

In this study, a fundamental research on understanding three dimensional soil moisture dynamics by both in-situ observation and numerical simulation on Shigaraki forest was acheived. <br>

DOI： 10.11520/jshwr.29.0_84

researchmap

Language：English   Publishing type：Lecture material (seminar, tutorial, course, lecture, etc.)  

researchmap

Language：English   Publishing type：Article, review, commentary, editorial, etc. (international conference proceedings)  

researchmap

Language：English   Publishing type：Research paper, summary (international conference)  

researchmap

Language：Japanese   Publisher：土木学会  

DOI： 10.2208/jscejer.71.I_369

researchmap

Language：English   Publishing type：Article, review, commentary, editorial, etc. (international conference proceedings)  

researchmap

Language：English   Publishing type：Research paper, summary (international conference)  

researchmap

Language：English   Publishing type：Research paper, summary (international conference)  

researchmap

J-GLOBAL

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

DOI： 10.11520/jshwr.27.0_100132

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

We performed Internet questionary survey subject to residents in Toyama and grasped the image for the climate change and examined a reporting policy to recognize the need of climate change measures.<br>The persons who feel a climate change at the present tend to feel the additional changes in the future. It is important to show the monitoring results of climate change for a citizen and promote the understanding for the climate change that had already occurred.<br>It has been shown that general images for the climate change promote to understand the need of the mitigation, and that it is important to explain about the climate change that might occur in the future even if it did not occur at the present in order to have people recognize widely the need of the adaptation.

DOI： 10.11520/jshwr.26.0.222.0

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

For the purpose of an integrated watershed environment management, a coupled river runoff and ocean circulation model is developed. Climate change impact on the hydrologic environment of Ise Bay is assessed by the model. Future climate change of rain fall amount and air temperature from 15 CMIP3 models are used as an atmospheric boundary conditions, and climate change of river discharge and water temperature from Hydro-BEAM prediction are also used as a river mouth boundary condition. Future SST in Ise Bay increases by about 2 degrees. Coastal areas are more strongly influenced. As a result from sensitivity analysis of the external force, it is found that the impact of external forces to the future SST calculation is in the order of open ocean> atmosphere> rivers.

DOI： 10.11520/jshwr.26.0.190.0

researchmap

Language：Japanese  

Makio dam in the Kiso River is a multipurpose dam which generates hydroelectric power and supplies water to Aichi Irrigation Project. Reservoir sedimentation increased in the Dam because of Nagano West Earthquake in 1984. It cost about 3 million yen to recover active storage capacity in 1996 by excavating deposited sediments. In the future, flow regime is going to change due to global warming which will have another impact on water resources management. In this study, we assessed multiple effects of the several reservoir sedimentation scenarios and future inflow changes calculated by GCM model and distributed hydrological model (Hydro-BEAM). Regarding hydroelectric power generation, annual total generation can be almost maintained by modifying seasonal dam operation rule. However, water supply to the Aichi Irrigation Project will be subject to severe damage mainly by the loss of active storage volume and additionally by future flow regime change.

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2433/196114

Language：Japanese  

The objective of this study is to show detailed analyzed results about the relations between upstream migration of sweetfish and water temperature at Nagara river, which were used in the study of Suzuki et al. (2014). Daily number of upstream migration data of sweetfish at Nagara river barrage, water temperature data at Ise-Oohashi bridge from water information system, and sea surface temperature (SST) at Ise Bay by Mie Prefecture Fisheries Research Institute were used. SST has good correlation with the total number 1% excess date. As SST becomes higher, the date becomes late. River water temperature has good correlation with the first group 5% excess date. As the river water temperature becomes higher, the date becomes early, which is the reverse tendency to SST. Water temperature difference (sea-river) has the good correlation with the first group 5% excess date. As the water temperature difference becomes higher, the upstream migration date becomes early. By these analyses, it is concluded that the first group 5% excess date is an effective index for the upstream migration start timing, and that water temperature difference (sea-river) is an effective water temperature index for the migration.

CiNii Books

J-GLOBAL

researchmap

Other Link： http://hdl.handle.net/2433/196111

Language：Japanese   Publisher：日本気象学会  

CiNii Books

researchmap

Language：Japanese  

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

A coupled river discharge and ocean circulation model was developed, which aimed for the effective tool for the integrated environment management of the watershed area including rivers and ocean. We applied the model to the heavy rainfall case around Kiso-sansen rivers and Ise Bay during April 2003. It was concluded that the calculated suspended sediment distribution was qualitatively conincident with the MODIS satellite observation.

DOI： 10.11520/jshwr.25.0.124.0

researchmap

Language：Japanese   Publisher：日本気象学会  

CiNii Books

researchmap

Language：Japanese   Publisher：日本気象学会  

CiNii Books

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

In order to evaluate the integrated assessment from river basins to the coast, a coupled river-ocean model was developed. An increase of river discharge from Arakawa, Edogawa and Tamagawa by the amount of 300m<SUP>3</SUP>/s results in the freshwater spread from Chiba to Yokohama with the counterclockwise extension. Mean water level at Shibaura rises about 1cm. After the incorporation of an advection-diffusion model, climate change impact assessment on the sediment discharge and water temperature environment will be investigated.

DOI： 10.11520/jshwr.24.0.134.0

researchmap

Language：Japanese   Publisher：日本気象学会  

CiNii Books

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

To clarify the impact of climate change on river discharge in a regional scale, a distributed hydrological model are applied for long-term hydrological impact assessment. To reduce uncertainty of future prediction by using GCM outputs, we used CMIP3 dataset for the multi-model ensemble approach. The future emission scenarios applied in this study are IPCC AR4 SRES A1B, A2 and B1. The results obtained in this study indicated that the hydrological impact of climate change is larger in the northern snow-dominant region than the southern warm-humid region, additionally the climate change impact on extreme hydrological events such as annual maximum flow or the minimum flow will be differ among the different region.

DOI： 10.11520/jshwr.24.0.146.0

researchmap

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

In this study, future change of precipitation characteristic was examined using the multi-GCMs of CMIP3 (including 24 models) and MRI-AGCM (3.1S and 3.2S). The standard deviation of monthly precipitation and daily precipitation intensity in the top 2% wereevaluated. The former is related to drought, the latter is related to flood. The result shows that both index would increase in the future, depending on the GCM.

DOI： 10.11520/jshwr.24.0.50.0

researchmap

Language：Japanese   Publisher：水文・水資源学会  

CiNii Books

J-GLOBAL

researchmap

researchmap

Language：Japanese   Publisher：社団法人日本気象学会  

本文データは学協会の許諾に基づきCiNiiから複製したものである

CiNii Books

researchmap

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10595510

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

A coupled river discharge and ocean circulation model was developed, in order to study the impact of river outflow on water environment of Tokyo Bay. A distributed Hydrological River Basin Environment Assessment Model (Hydro-BEAM) and RIAM ocean circulation model (RIAMOM) are connected at the river mouse as boundary conditions of river outflow. A result from case study simulation shows that fresh waters from river outflow are distributed in the north-west part of Tokyo Bay.

DOI： 10.11520/jshwr.23.0.72.0

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

A super-high-resolution (approximately 20km) global atmospheric general circulation model (AGCM20) is applied to project the changes in future weather extremes under the global warming environment. This model can reproduce the actual climate conditions more accurately than the previous lower resolution models. In this paper, we attempt to discuss about regional impacts of climate change from a hydrological viewpoints. To predict the hydrological impact in the regional scale, we used a distributed hydrological model called Hydro-BEAM. The results and discussion obtained in this study will contribute more appropriate integrated water resources management or mitigation strategies to mitigate future disaster risks under the global warming environment.

DOI： 10.11520/jshwr.23.0.47.0

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

Quantitative evaluation of climate change largely depends on numerical simulations using a climate model. Thus, it is important to precisely understand the output of the model. This study examines the accuracy of CMIP3 multi-climate models in the IPCC AR4 over the Japanese land area. The authors discuss screening appropriate climate models for Japan and uncertainty of simulation outputs.

DOI： 10.11520/jshwr.23.0.42.0

researchmap

Language：Japanese   Publisher：日本気象学会  

CiNii Books

researchmap

Language：English  

CiNii Books

researchmap

Other Link： http://hdl.handle.net/2433/129362

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

DOI： 10.11520/jshwr.22.0.66.0

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

This paper proposes a newly extended method for estimation of hydrological distributions of subsurface events in space and time based on observed data. To extend spatial estimates into spatiotemporal ones, a conversion parameter of temporal-distance is newly defined and introduced into the kriging equations using trend and covariance functions. This parameter equivalently converts a temporal gap into a spatial distance in time-related terms of those functions. It can be shown that the proposed method with the conversion parameter is useful and applicable to a spatiotemporal estimation via the numerical tests and be concluded that the conjunctive correlation of the ramdom component in space and time is better in this method.

DOI： 10.11520/jshwr.22.0.56.0

researchmap

Language：English   Publisher：Research Institute for Humanity and Nature（RIHN）  

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

DOI： 10.11520/jshwr.21.0.45.0

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

DOI： 10.11520/jshwr.21.0.70.0

researchmap

Language：Japanese  

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

DOI： 10.11520/jshwr.21.0.74.0

researchmap

Language：English   Publisher：Research Institute for Humanity and Nature（RIHN）  

The most severe dry-up has occurred in the downstream of the Yellow River in 1997. After that, it was legislated for the conservation of water, and was improved on the order of water use in each irrigation area. Since 2000, incidents relevant to dry-up seem to have not happened. The river water of the Yellow River at the mouth, however, continues to let low volume flow as the same as 1997. Its reasons and effect were/are studied as follows. The Yellow River project in RIHN was started to clarifying why the dry-up has occurred and what kinds of effects are to be occurred in surrounding circumstances. Now, the reason of the dry-up are considered due to the complicated factors, these are the decrease of precipitation, over-use of river water in large irrigation districts and recovery of vegetation on Loess Plateau. Though sediment production on Loess Plateau seems to decrease, the river bed in downstream of the Yellow River continues to rise up. It will enhance the danger of flood disaster in the North China Plain. On the other-hand, the environment of Bo-Hai Sea has changed in both water and material inputs from the Yellow River. Its effects are now investigated.

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

China faces the need to expand its food supply in order to meet the rising food demand of its growing population. The Yellow River basin, one of the important regions in China for agriculture production, has been able to increase its production thanks to by improvements in productivity. Environmental issues, water shortages in particular, have become more serious, however, and excessive agricultural water use may worsen the situation. Therefore, the effective use of water resources is essential to avoid this water shortage. This study examined estimation technique of the efficiency of agricultural water use in the Yellow River basin by using statistical data, land use data, and hydrological model. Results from this study indicate that water use efficiency in upstream region is low, especially worsen in the large irrigation districts.

DOI： 10.11520/jshwr.20.0.110.0

researchmap

Language：English   Publisher：YELLOW RIVER CONSERVANCY PRESS  

To clarify the long - term water balance of the Yellow River basin, a new semi - distributed hydrological model was developed and applied to the middle reaches of the Yellow River basin. This analysis focused on the period during the past 40 years (1960 - 2000) using 128 meteorological stations data and high resolution remote sensing data. The model was based on soil - vegetation - atmosphere - transfer scheme and runoff formation model (SVAT - HYCYMODEL). To take the influence of vegetation change into consideration, an index of vegetation cover ratio (VCR) was introduced. By applying a VCR to the original hydrological model, the observed river discharge in the middle reaches of the Yellow River basin was captured by the model. According to the model simulation, it was found that the discharge from tributaries in the middle reaches of the Yellow River basin has been decreasing rapidly. Furthermore, the discharge ratio (discharge/precipitation) was also decreased significantly during the past 40 years. Consequently, we confirmed that the available water resources in the middle reaches of the Yellow River basin decreased considerably with not only precipitation decrease, but also increasing evapotranspiration ratio (evapotranspiration/precipitation) with the massive land - use change in the Loess Plateau.

Web of Science

researchmap

Language：Japanese   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

To clarify the influences of climate change and human activities on river discharge, the long-term (1960–2000) water balance in the middle reaches of the Yellow River basin was analyzed using a hydrological model. To estimate evapotranspiration from various land-use types, a high resolution land surface classification map in 2000 was used.The model simulation results showed that the impact of vegetation recovery on the Loess Plateau in the middle reaches of the Yellow River basin had changed with the climate (wet or dry) conditions.

DOI： 10.11520/jshwr.20.0.15.0

researchmap

Language：Japanese   Publisher：水文・水資源学会  

CiNii Books

researchmap

Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

In order to clarify the hydrological process in a large river basin like the Yellow River, we have to take not only natural factors but also artificial factors into consideration.<br>In this study, we attempt to develop a new model and procedures to clarify the influence of human impacts on the river runoff of the Yellow River basin. Although there are various human activities that affect the river runoff, we focused on the following three factors: (1) large dams operation, (2) irrigation water intake from the river channels and (3) land use change during the period from 1960 to 2000.

DOI： 10.11520/jshwr.19.0.123.0

researchmap

Language：English   Publisher：Research Institute for Humanity and Nature（RIHN）  

researchmap

Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

In order to clarify the hydrological process of the Yellow River basin, understanding of the phenomenon by the physical based model reflecting various conditions, such as a meteorological factor, and a geographical condition, vegetation covering or other land use condition, is indispensable.<br> Furthermore, in the Yellow River basin, there are a lot of water reservoir dams for electric power generation or large-scale irrigation. Thus, the hydrological model with taking these influences into account is needed.<br> In this study, we constructed a simple model with consideration to estimate the influence of the runoff controlled by the dam.<br> Furthermore, we examined the influence of a natural factor and land use change to the runoff formation in the source area of the Yellow River basin using routine meteorological data and remote sensing data.

DOI： 10.11520/jshwr.18.0.74.0

researchmap

Language：Japanese   Publisher：日本森林学会  

DOI： 10.11519/jfsc.116.0.432.0

researchmap

Publisher：The Japanese Forestry Society  

DOI： 10.11519/jfs.115.0.C14.0

researchmap

Language：Japanese   Publisher：日本生態学会  

DOI： 10.14848/esj.ESJ50.0_219_4

researchmap

Language：Japanese   Publisher：日本生態学会  

DOI： 10.14848/esj.ESJ50.0_157_2

researchmap

Publisher：The Japanese Forestry Society  

We estimated rainfall interception using simple model consists of two continuous tanks correspond to canopy and litter interception processes. This model predicts the effect of these two interception processes separately. The canopy tank model calculates the amount of throughfall, stemflow and canopy interception from the gross rainfall data. On the other hand, the litter interception model calculates the litter interception from the throughfall data estimated by the canopy tank model, and also evaporation ratio from the litter layer estimated by the relative water content of the litter layer. We applied this model to coniferous C. japonica (Cryptomeria japonica D. don) and broad - leaved L. edulis (Lithocarpus edulis Nakai)plantation forest. Estimated annual interception loss showed good response to various rainfall conditions.

DOI： 10.11519/jfs.114.0.387.0

researchmap

Language：Japanese  

CiNii Books

researchmap

researchmap

In order to clarify the hydrological process in a large river basin like the Yellow River, we have to take not only natural factors but also artificial factors into consideration.<br>In this study, we attempt to develop a new model and procedures to clarify the influence of human impacts on the river runoff of the Yellow River basin. Although there are various human activities that affect the river runoff, we focused on the following three factors: (1) large dams operation, (2) irrigation water intake from the river channels and (3) land use change during the period from 1960 to 2000.

researchmap

Language：Japanese  

China faces the need to expand its food supply in order to meet the rising food demand of its growing population. The Yellow River basin, one of the important regions in China for agriculture production, has been able to increase its production thanks to by improvements in productivity. Environmental issues, water shortages in particular, have become more serious, however, and excessive agricultural water use may worsen the situation. Therefore, the effective use of water resources is essential to avoid this water shortage. This study examined estimation technique of the efficiency of agricultural water use in the Yellow River basin by using statistical data, land use data, and hydrological model. Results from this study indicate that water use efficiency in upstream region is low, especially worsen in the large irrigation districts.

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

researchmap

Language：Japanese  

To clarify the influences of climate change and human activities on river discharge, the long-term (1960–2000) water balance in the middle reaches of the Yellow River basin was analyzed using a hydrological model. To estimate evapotranspiration from various land-use types, a high resolution land surface classification map in 2000 was used.The model simulation results showed that the impact of vegetation recovery on the Loess Plateau in the middle reaches of the Yellow River basin had changed with the climate (wet or dry) conditions.

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese   Presentation type：Poster presentation  

researchmap

Language：Japanese   Presentation type：Poster presentation  

researchmap

Language：Japanese   Presentation type：Poster presentation  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：English   Presentation type：Poster presentation  

researchmap

Language：English   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese  

researchmap

Language：Japanese   Presentation type：Poster presentation  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

本研究では、1960年代から1990年代までの40年間を対象に、黄河全流域の水収支を半分布型水文モデルを用いて解析し、新たな黄河断流のメカニズム解明を試みた。その結果、黄河下流域の河川流量の減少の大部分（約7割）は、下流域に水を供給する黄河源流域から中流域までの河川流量の減少によるもので、残りの3割が、下流域内での水消費量の増加によることがわかった。下流域内での水消費量は主に灌漑面積の増加に伴う灌漑用水量の増加に規定されており、下流域への供給水量の減少は、黄河中流域からの流出量の減少に起因することがわかった。

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

For the purpose of an integrated watershed environment management, a coupled river runoff and ocean circulation model is developed. Climate change impact on the hydrologic environment of Ise Bay is assessed by the model. Future climate change of rain fall amount and air temperature from 15 CMIP3 models are used as an atmospheric boundary conditions, and climate change of river discharge and water temperature from Hydro-BEAM prediction are also used as a river mouth boundary condition. Future SST in Ise Bay increases by about 2 degrees. Coastal areas are more strongly influenced. As a result from sensitivity analysis of the external force, it is found that the impact of external forces to the future SST calculation is in the order of open ocean> atmosphere> rivers.

researchmap

Language：Japanese  

We performed Internet questionary survey subject to residents in Toyama and grasped the image for the climate change and examined a reporting policy to recognize the need of climate change measures.<br>The persons who feel a climate change at the present tend to feel the additional changes in the future. It is important to show the monitoring results of climate change for a citizen and promote the understanding for the climate change that had already occurred.<br>It has been shown that general images for the climate change promote to understand the need of the mitigation, and that it is important to explain about the climate change that might occur in the future even if it did not occur at the present in order to have people recognize widely the need of the adaptation.

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

A coupled river discharge and ocean circulation model was developed, which aimed for the effective tool for the integrated environment management of the watershed area including rivers and ocean. We applied the model to the heavy rainfall case around Kiso-sansen rivers and Ise Bay during April 2003. It was concluded that the calculated suspended sediment distribution was qualitatively conincident with the MODIS satellite observation.

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

In this study, future change of precipitation characteristic was examined using the multi-GCMs of CMIP3 (including 24 models) and MRI-AGCM (3.1S and 3.2S). The standard deviation of monthly precipitation and daily precipitation intensity in the top 2% wereevaluated. The former is related to drought, the latter is related to flood. The result shows that both index would increase in the future, depending on the GCM.

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

In order to evaluate the integrated assessment from river basins to the coast, a coupled river-ocean model was developed. An increase of river discharge from Arakawa, Edogawa and Tamagawa by the amount of 300m<SUP>3</SUP>/s results in the freshwater spread from Chiba to Yokohama with the counterclockwise extension. Mean water level at Shibaura rises about 1cm. After the incorporation of an advection-diffusion model, climate change impact assessment on the sediment discharge and water temperature environment will be investigated.

researchmap

Language：Japanese  

To clarify the impact of climate change on river discharge in a regional scale, a distributed hydrological model are applied for long-term hydrological impact assessment. To reduce uncertainty of future prediction by using GCM outputs, we used CMIP3 dataset for the multi-model ensemble approach. The future emission scenarios applied in this study are IPCC AR4 SRES A1B, A2 and B1. The results obtained in this study indicated that the hydrological impact of climate change is larger in the northern snow-dominant region than the southern warm-humid region, additionally the climate change impact on extreme hydrological events such as annual maximum flow or the minimum flow will be differ among the different region.

researchmap

Language：Japanese  

A super-high-resolution (approximately 20km) global atmospheric general circulation model (AGCM20) is applied to project the changes in future weather extremes under the global warming environment. This model can reproduce the actual climate conditions more accurately than the previous lower resolution models. In this paper, we attempt to discuss about regional impacts of climate change from a hydrological viewpoints. To predict the hydrological impact in the regional scale, we used a distributed hydrological model called Hydro-BEAM. The results and discussion obtained in this study will contribute more appropriate integrated water resources management or mitigation strategies to mitigate future disaster risks under the global warming environment.

researchmap

Language：Japanese  

A coupled river discharge and ocean circulation model was developed, in order to study the impact of river outflow on water environment of Tokyo Bay. A distributed Hydrological River Basin Environment Assessment Model (Hydro-BEAM) and RIAM ocean circulation model (RIAMOM) are connected at the river mouse as boundary conditions of river outflow. A result from case study simulation shows that fresh waters from river outflow are distributed in the north-west part of Tokyo Bay.

researchmap

Presentation type：Poster presentation  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

This paper proposes a newly extended method for estimation of hydrological distributions of subsurface events in space and time based on observed data. To extend spatial estimates into spatiotemporal ones, a conversion parameter of temporal-distance is newly defined and introduced into the kriging equations using trend and covariance functions. This parameter equivalently converts a temporal gap into a spatial distance in time-related terms of those functions. It can be shown that the proposed method with the conversion parameter is useful and applicable to a spatiotemporal estimation via the numerical tests and be concluded that the conjunctive correlation of the ramdom component in space and time is better in this method.

researchmap

Language：Japanese  

IPCCの第4次評価報告書(AR4)における排出シナリオ(SRES)A1Bに基づく水平空間解像度約20kmの超高解像度全球大気大循環モデル(MRI AGCM20, TL969)出力を用いて、石狩川流域の気候変動に伴う将来の流域災害環境の予測を試みた。流域スケールで起こりうる様々な災害（洪水・渇水・土砂流出等）の影響をより詳細に評価するために、空間分解能1km、時間分解能10分の分布型流域環境評価モデル（Hydro-BEAM）を用いた。Hydro-BEAMへの入力となるGCMの気象要素としては、地表到達雨量と融雪量および実蒸発散量を用い、さらにGCM出力の時空間的な特徴を把握するため、地上気象観測データ(AMeDAS/SDP)を用いた地表面熱収支(SVAT)モデルの出力値との比較も試みた。

researchmap

Language：Japanese  

近年，各地で異常気象の発生が報告されており，安定的な水資源供給に不安が生じている．この傾向は，気候変動によりさらに助長されることも示唆されており，流域単位での総合的水資源管理が不可欠である．本研究では，GCM出力値を流域単位で適用し，気候変動前後の水資源分布の時空間的な推定，比較を行った．結果，河川流況の変化，洪水ピーク時の大幅な上昇など，水資源管理がより困難になることが示唆され，気候変動の影響が流域単位においても顕著にあらわれることが示された．将来，渇水や洪水の危険性の増大が懸念される．また，Hydro-BEAMの長所として，分布型流出モデルの特性を生かし，ダムモデル同様，様々なモデルをその中に組み込むことが出来る点が挙げられる．本研究では，条件を単純化し，生態系への評価も合わせて行った．

researchmap

Language：Japanese  

本研究では、水平解像度20kmの超高解像度GCMデータを用いて、淀川流域の将来流量の予測を試みた。その結果、高解像度のGCMであってもバイアス補正を行わないと流域の降水量やその季節変化特性を正確に再現できないことがわかった。また、淀川流域では、温暖化に伴って将来の降水量は増加するが、それと同時に蒸発散量も増加するため、年間の水収支には大きな変化はみられなかったが、貯水池操作の影響を考慮したモデル（HydroBEAM）の出力結果からは、極端現象（夏期の洪水や冬期の渇水）に伴う災害リスクが増加する可能性があることが示唆された。本研究で得られる流量予測は、将来起こりうる極端現象時の斜面崩壊リスクや都市域の洪水氾濫リスク評価にも貢献しうる。また、現状ダム操作の将来における有効性や下流への治水・利水安全性の検討から将来を見据えた総合流域管理手法の確立を目指していきたい。

researchmap