Browsing by Autor "Pablo Fuchs"

Now showing 1 - 5 of 5

A New Database of Meteorological and Glaciological Observations: Tarija Glacier, Tropical Andes
(2021) Pablo Fuchs; Javier Mendoza
&lt;p&gt;We present a numerical and geographical database for the Tarija Glacier in the Tropical Andes (68.2&amp;#176; W, 16.2&amp;#176; S, 4820-5380 m.a.s.l.). The database consists of meteorological data, mass balance observations, and variations in glacier front positions. Meteorological data was obtained by an automatic weather station (AWS) located on the glacier surface that includes the following variables: precipitation, temperature, incoming shortwave radiation, relative humidity, wind speed and wind direction. Mass balance for this glacier was observed on a monthly basis in an ablation stake network and annually in a snow pit at 5230 m.a.s.l. The glacier front topography was monitored annually using a DGPS survey. We set up the database using the relational database engine PostgreSQL which is capable of managing geospatial data through the PostGIS extension. The SAGA system was used for image analysis and mapping. Data quality control and further processing was carried out in the R environment which has interfaces to the PostgreSQL database system and SAGA, as well as several additional packages for statistical analyses and modelling. The database contains data spanning the 2011-2018 period and would be useful for multiple applications including environmental and ecological modeling, water resources assessment, and climate change studies.&lt;/p&gt;
ESTIMATION OF GLACIER MELT IN THE TROPICAL ZONGO WITH AN ENHANCED TEMPERATURE-INDEX MODEL
(2013) Pablo Fuchs; Yoshihiro ASAOKA; So Kazama
An enhanced temperature-index model including albedo and shortwave radiation has been applied to the tropical Zongo glacier. The model satisfactorily simulated the daily discharges and their seasonal variations with an efficiency of 0.71 (Nash-Sutcliffe). The energy balance analysis revealed that three factors mainly control melt on this glacier: incoming shortwave radiation, incoming longwave radiation and sensible heat flux. Accordingly, the model differentiates between temperature-dependent and temperature-independent components moving towards a more physically based but still simple model. Modelling was improved with respect to the traditional degree-day method in the wet season characterized by simultaneous accumulation and strong melting while capturing the low melt rates found in the dry season. However the model missed some peaks in discharge due to the underestimation of precipitation at the low elevation meteorological station.
Mass balance estimation on the Zongo glacier, Bolivia, using a semi-distributedconceptual model (SCM)
(Copernicus Publications, 2026) Gabriela Quispe; Carlos Cárdenas; Pablo Fuchs; Alvaro Soruco; Antoine Rabatel
Abstract. The mass balance of a glacier is used to quantify the accumulation and melting processes, which affect its mass. With this information, it is possible to infer the variation in water reserves, which will support decision-making based on the supply and demand of water. The objective of this work is to show the results of a mass balance model applied to the Zongo Glacier in Bolivia. The model used is a semi-distributed conceptual model (Schaefli et al., 2005). The monthly sensitivity of the mass balance and discharge predictions was evaluated for the hydrological years 2004-2006. Our results show that the model presents discharge and mass balance values with an MAE error of 2.4 and a BIAS of 1.3 concerning the data observed in the glacier. Simple conceptual models can be a valuable tool to project the behavior of a glacial basin, but only if it has sufficient information for the calibration and validation of the model parameters.
Modelling melt, runoff, and mass balance of a tropical glacier in the Bolivian Andes using an enhanced temperature-index model
(2016) Pablo Fuchs; Yoshihiro ASAOKA; So Kazama
This paper evaluates the feasibility of applying a coupled melt, runoff, and mass balance model to the tropical Zongo glacier (Cordillera Real, Bolivia) during two hydrological years. Melt rate was estimated using the standard degree-day method (DDM) and an enhanced temperature-index model (ETI). The latter was run with values of parameters obtained for Haut Glacier d’Arolla and a recalibrated parameter set for Zongo glacier. Glacier mass balance was calculated using snowfall inputs and modelled melt and sublimation. Estimated monthly mass balance and discharge were compared with observations from a stake network in the ablation zone and data from a hydrometric station. We concluded that ETI model agrees very well with the reference runoff and mass balance. Net mass balance over the whole glacier was predicted accurately in the ablation zone, but the model overestimated mass balance in the accumulation zone owing to the absence of observations at higher elevations; the equilibrium line altitude and accumulation area ratio were predicted within reasonable limits. The results demonstrate that ETI model is applicable in tropical conditions, provided that the parameters are recalibrated for the climatic settings of this 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