Browsing by Autor "Tsuyoshi Kinouchi"

Now showing 1 - 6 of 6

ASSESSMENT OF AQUATIC ENVIRONMENTAL IMPACT BY A FUTURE CLIMATE CHANGE IN A RESERVOIR LOCATED IN THE BOLIVIAN ANDES
(2013) Keisuke TANI; Makoto Umeda; Tsuyoshi Kinouchi; Yoshihiro ASAOKA; Marcelo Gorritty
Glacial melt water is major water resourcess in and around La Paz, the capital of Bolivia in the center of South America. However, it is predicted that the glaciers in this area will disappearin 30 or 40 years because of climate change. In this study, water temperature around the end of the century in Tuni Reservoir, which is located at downstream of glaciers and provides domestic water to the cities nearby, were predicted with 1-dimensional hydraulic model using the outputs of a global climate model. The results indicate that surface temperature in the reservoir will basically depend on temperature rise. However, inflow rates will decrease about 60% by glacier disappearance and change more variably each year. So, it is important to consider how to take and convey water in the future.
Characterization of recent glacier decline in the Cordillera Real by LANDSAT, ALOS, and ASTER data
(Elsevier BV, 2013) Tong Liu; Tsuyoshi Kinouchi; Fabiola Ledezma
Glacier Mass Balance and Catchment-Scale Water Balance in Bolivian Andes
(Fuji Technology Press Ltd., 2016) Tong Liu; Tsuyoshi Kinouchi; Javier Mendoza; Yoichi Iwami
In investigating glacier mass balance and water balance at Huayna Potosi West, a glacierized basin in the Bolivian Andes (Cordillera Real), we used a remote sensing method with empirical area-volume relationships, a hydrological method with runoff coefficients, and water balance method. Results suggest that remote sensing method based on the glacier area from satellite images and area-volume relationships is too imprecise to use in performing analysis in short time intervals. Glacier mass balance obtained using a new area-volume relationship was, however, similar to that obtained by the water balance method, thus proving that the new area-volume relationship is reasonable to use for analyzing glaciers within a certain size range. The hydrological method with a runoff coefficient considered glacier as the only storage for saving or contributing to runoff and nonglacier area as the only source of evaporation. We applied a fixed runoff coefficient of 0.8 without considering wet or dry seasons in nonglacier areas – a method thus sensitive to meteorological and hydrological data. We also did not consider glacier sublimation. The water balance method is applicable to the study region and excelled other methods in terms of resolution, having no empirical coefficients, and considering sublimation and evaporation. Among its few limitations are possibly underestimating evaporation and runoff over nonglacier areas during wet months and thus possibly overestimating glacier contribution at mean time.
IMPACT OF GLACIER DISAPPEARANCE ON RUNOFF FROM A GLACIERIZED CATCHMENT IN THE ANDES
(2013) Tsuyoshi Kinouchi; Fabiola Ledezma; Tong Liu; Javier Mendoza
We predicted the hydrological impact of glacier retreat in the glacierized catchment located in Bolivian Andes by applying a grid-based physically distributed runoff model. The capability of the model was improved by including snow and ice melt processes, in which temperature, solar radiation and humidity were taken into accounts based on our field observation. Runoff retarding by the freezing soil was also considered. Given hourly meteorological conditions and spatial distributions of land cover, precipitation and air temperature, the model result agreed well with observed flow rates. After the full glacier retreat, the flow rate is estimated to be significantly reduced in the dry season while the impact is less in the wet season. We found that glacier melts mostly occurred in the early stage of the wet season. In addition to glacier disappearance, the rise in air temperature increased the discharge during major precipitation events but reduced the amount of snow accumulated over the catchment.
Modeling glacier melt and runoff in a high-altitude headwater catchment in the Cordillera Real, Andes
(2013) Tsuyoshi Kinouchi; T. Liu; J. Mendoza; Yoshihiro ASAOKA
Abstract. Runoff from catchments with partial glacier cover is an integrated process of glacier melt, snowmelt, and surface and subsurface runoff of meltwater and rain from glacierized and non-glacierized areas. Additionally, inherent characteristics of the tropical Andes such as large meteorological variability, high elevation and steep slopes, hydrological effects of wetlands and lakes, and rapid glacier retreat make it difficult to model glacio-hydrological responses under changing climate. In this study, we developed a semi-distributed conceptual model applicable to partially glacierized catchments in the tropical Andes that considers all of these aspects, and we applied the model to the Huayna Potosi West headwater catchment in the Cordillera Real, Bolivia. Based on the latest 2 yr dataset of meteorological and hydrological monitoring, we showed the spatial and temporal variability of air temperature and precipitation in the region, and the dataset was used to calibrate model parameters and validate the performance of the daily runoff simulation. Variations in the simulated streamflow agreed well with the observed seasonal and temporal variations, and the result also showed that uncertainty pertaining to the spatial and temporal variations in air temperature and precipitation as well as the retarding effect of a wetland and lake strongly affected the runoff hydrograph. The simulated runoff components indicated that runoff from glacier melt occurs mainly in the initial period of the wet season, from October to early December, and in the late period of the wet season, March and April, although the runoff is relatively small in the latter period. Between these two periods in the wet season, major runoff components were estimated to be subsurface runoff in the non-glacierized area and surface runoff due to snowmelt. Given the future meteorological conditions based on the observational data and a predictive general circulation model output, the model quantified the long-term changes in runoff, glacierized area, and cumulative glacier and snow mass balance. The glacier retreat is estimated to continue to 2050, with the magnitude of area decrease and negative cumulative mass balance depending on the increasing temperature trend used. For higher temperature trends, in particular, greater seasonal variation in runoff and larger contributions from subsurface runoff and surface runoff by rainfall were simulated to occur in the wet season, but the change in annual total runoff between the present and 2050 was not significant. These results suggest that it is important to consider how to best adapt to greater seasonal runoff variations in terms of water availability in the downstream region.
Water security in high mountain cities of the Andes under a growing population and climate change: A case study of La Paz and El Alto, Bolivia
(Elsevier BV, 2019) Tsuyoshi Kinouchi; Takashi Y. Nakajima; Javier Mendoza; Pablo Fuchs; Yoshihiro ASAOKA