Balance de masa geodésico multidecadal de la sierra nevada de la Araucanía combinando diferentes fuentes de datos de altimetría.
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Date
2024
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Concepción
Abstract
En esta tesis se presentan los resultados de un estudio realizado en los glaciares de la Sierra Nevada en la región de la Araucanía en donde el objetivo principal fue estimar la tasa de adelgazamiento anual entre los años 1998 y 2007 dividido en dos períodos. Las fuentes de información de datos de altimetría para las fechas 1998 y 2007 corresponden al Servicio Aerofotogramétrico de la Fuerza Aérea de Chile en donde se obtuvieron set de fotografías aéreas para cada una, y para el año 2000 fue un modelo SRTM “Shuttle Radar Topography Mission” además este será el MDE referencial para la construcción de los modelos digitales con las fotografías, asimismo también fue el MDE maestro que se utilizó como referencia en el coregistro.
La normalización de los MDE es un proceso previo que consiste en dos procedimientos. El primero se ejecuta a través de métodos de interpolación, en donde los modelos se llevan a un sistema de referencia común y en un mismo tamaño de pixel. El segundo es el co-registro, el cual corrige los errores horizontales y verticales del MDE ajustándolo al de referencia. El resultado de este proceso previo pone en evidencia que estas transformaciones son necesarias ya que influyen en la magnitud de los errores en cada MDE transformado.
Contando con lo anterior aplicado se pudo realizar las operaciones aritméticas para obtener la tasa de adelgazamiento. Del cálculo de las variaciones entre el primer periodo 1998-2000 resultó tener un promedio de -5,34 m, mientras que el periodo 2000-2007 dio un promedio de +8,61 m, considerando en este último periodo sólo un 95% del contorno total de Sierra Nevada. La tasa de adelgazamiento anual fue de -2,27 mwe/a y 1,05 mwe/a respectivamente.
This thesis presents the results of a study carried out on the glaciers of the Sierra Nevada in the Araucanía region where the main objective was to estimate the annual thinning rate between the years 1998 and 2007 divided into two periods. The sources of altimetry data information for the dates 1998 and 2007 correspond to the Aerophotogrammetric Service of the Chilean Air Force where sets of aerial photographs were obtained for each one, and for the year 2000 it was an SRTM model “Shuttle Radar Topography Mission” In addition, this will be the reference MDE for the construction of the digital models with the photographs, it was also be the master MDE that was used as a reference in the co-registration. The standardization of the MDE is a prior process that consists of two procedures. The first is executed through interpolation methods, where the models are taken to a common reference system and in the same pixel size. The second is co-registration, which corrects the horizontal and vertical errors of the EDM by adjusting it to the reference one. The result of this previous process shows that these transformations are necessary since they influence the magnitude of the errors in each transformed MDE. With the above applied, arithmetic operations could be performed to obtain the weight loss rate. From the calculation of the variations between the first period 1998-2000 it turned out to have an average of -5.34 m, while the period 2000-2007 gave an average of +8.61 m, considering in this last period only 95% of the contour total of Sierra Nevada. The annual thinning rate was -2.27 mwe/a and 1.05 mwe/a respectively.
This thesis presents the results of a study carried out on the glaciers of the Sierra Nevada in the Araucanía region where the main objective was to estimate the annual thinning rate between the years 1998 and 2007 divided into two periods. The sources of altimetry data information for the dates 1998 and 2007 correspond to the Aerophotogrammetric Service of the Chilean Air Force where sets of aerial photographs were obtained for each one, and for the year 2000 it was an SRTM model “Shuttle Radar Topography Mission” In addition, this will be the reference MDE for the construction of the digital models with the photographs, it was also be the master MDE that was used as a reference in the co-registration. The standardization of the MDE is a prior process that consists of two procedures. The first is executed through interpolation methods, where the models are taken to a common reference system and in the same pixel size. The second is co-registration, which corrects the horizontal and vertical errors of the EDM by adjusting it to the reference one. The result of this previous process shows that these transformations are necessary since they influence the magnitude of the errors in each transformed MDE. With the above applied, arithmetic operations could be performed to obtain the weight loss rate. From the calculation of the variations between the first period 1998-2000 it turned out to have an average of -5.34 m, while the period 2000-2007 gave an average of +8.61 m, considering in this last period only 95% of the contour total of Sierra Nevada. The annual thinning rate was -2.27 mwe/a and 1.05 mwe/a respectively.
Description
Tesis presentada para optar el título de Geógrafa
Keywords
Medición de altitudes, Glaciares, Sierra Nevada (Chile)