Browsing by Autor "Tong Liu"

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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.