Dinámica del glaciar Znosko, Antártida
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Authors
Bello Chirinos, Cinthya Elizabeth
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Abstract
Los glaciares son grandes masas de hielo en movimiento que conforman la criósfera, y son considerados indicadores sensibles al cambio climático. Desde la era pre-industrial se registró un incremento gradual de la temperatura alrededor del mundo, siendo más intenso en la Antártida, tendencia que se prevé continuará y originará una gran reducción del volumen glaciar. El presente trabajo de investigación tuvo como objetivo evaluar la dinámica del glaciar Znosko (Isla Rey Jorge, Antártida). Para lograr este objetivo se analizó el comportamiento temporal de la temperatura superficial del aire, empleando series de datos a resolución mensual procedente de 05 estaciones meteorológicas (periodo 1969-2019) ubicadas cerca al glaciar de estudio, que fueron sometidas a un análisis de tendencias (test de Mann-Kendall y regresión lineal y Spearman Rho), quiebres (test Cusum) y teleconexiones (Índice Oceánico el Niño, Índice de Oscilación del Sur, Índice de Oscilación Decadal del Pacífico y el Modo Anual del Sur). Seguidamente se determinó el balance de masa de dicho glaciar por método glaciológico y geodésico durante el verano austral 2018 2019 y 2019-2020, empleando una red de 19 balizas instaladas en el glaciar para registrar la perdida de hielo superficial in situ y comparar los resultados derivados de la percepción remota (modelos de elevación digital obtenidos de un vuelo con dron). Finalmente, se estimó la distribución y espesor del hielo de forma directa empleando un georradar de penetración terrestre (GPR) e indirecta aplicando el software Glabtop (verano austral 2018-2019 y 2019 2020). Los resultados muestran que las temperaturas medias de verano en la Isla Rey Jorge están por encima de cero entre diciembre a marzo, registrándose una variación negativa ( 0.1 a -0.3 °C) durante el periodo 2001-2019 (verano). El análisis de teleconexiones mostró que la variabilidad interanual de la temperatura superficial del aire se correlaciona (directa y positiva) fuertemente con el Modo Anual del Sur durante el otoño y en menor medida en primavera e invierno y con la temperatura media anual. El balance de masa por método glaciológico de este glaciar fue negativo registrándose pérdidas de -590.7 mm.w.e (2018 2019) y -686.7 mm.w.e (2019-2020), mientras que el método geodésico estimó una pérdida de -307.2 mm.w.e.. La distribución del espesor de hielo tanto modelado (Glabtop) como medido (GPR) fue heterogénea a lo largo de la lengua del glaciar Znosko, fluctuando desde un valor mínimo (0 m) a lo largo de los bordes hasta un máximo de 132 m (Glabtop) y 155 m (GPR) ubicados en la zona de acumulación y la parte central del glaciar, respectivamente. En conclusión, se observó que a pesar de registrarse una reducción de temperatura durante el verano entre el 2001-2019 en la Isla Rey Jorge, existe una pérdida de masa superficial del glaciar Znosko posiblemente debido a la reducción de la precipitación solida (nieve) que puede influir en el futuro en la distribución del espesor de hielo.
Glaciers are large ice masses in movement that are part of the cryosphere, and are considered sensitive indicators of climate change. Since the pre-industrial era, there has been a gradual increase in temperature around the world, being more intense in Antarctica, a trend that is expected to continue and cause a large reduction in glacier volume. The objective of this research work was to evaluate the dynamics of the Znosko Glacier (King George Island, Antarctica) were evaluated. To achieve this objective, the temporal behavior of the surface air temperature was analyzed, using data series at monthly resolution from 05 meteorological stations (period 1969-2019) located near the glacier, which were subjected to a trend (Mann Kendall, Linear Regression and Spearman Rho test), distribution (Cusum test) and teleconnections (El Niño Ocean Index, Southern Oscillation Index, Pacific Decadal Oscillation Index and Southern Annual Mode) analysis. Subsequently, the mass balance of Znosko glacier was determined by glaciological and geodesic method during the austral summer 2018-2019 and 2019-2020, using a network of 19 stakes installed on the glacier to record the surface ice mass loss in situ and compare the results derived from remote sensing (digital elevation models obtained from a drone flight). Finally, the distribution and thickness of the ice was estimated directly using a ground penetrating georadar (GPR) and indirectly with the Glabtop software (austral summer 2018-2019 and 2019-2020). The results show that the average summer temperatures on King George Island are above zero between December to March, registering a negative variation (-0.1 to -0.3 °C) during the period 2001-2019 (summer). The teleconnection analysis showed that the interannual variability of the air surface temperature is strongly correlated (direct and positive) with the Southern Annual Mode during autumn and to a lesser extent in spring and winter and with the mean annual temperature. The mass balance by glaciological method of this glacier was negative, registering losses of -590.7 mm.w.e (2018-2019) and -686.7 mm.w.e (2019-2020), while the geodetic method estimated a loss of -307.2 mm. w.e. The distribution of both modeled (Glabtop) and measured (GPR) ice thickness was heterogeneous along the Znosko glacier tongue, varying from a minimum value (0 m) along the edges to a maximum of 132 m (Glabtop) and 155 m (GPR) located in the accumulation zone and the central part of the glacier, respectively. In conclusion, it was observed that despite registering a temperature reduction during the summer between 2001-2019 on King George Island, there is a surface mass loss in Znosko glacier, possibly due to the reduction in solid precipitation (snow) that may influence the distribution of ice thickness in the future.
Glaciers are large ice masses in movement that are part of the cryosphere, and are considered sensitive indicators of climate change. Since the pre-industrial era, there has been a gradual increase in temperature around the world, being more intense in Antarctica, a trend that is expected to continue and cause a large reduction in glacier volume. The objective of this research work was to evaluate the dynamics of the Znosko Glacier (King George Island, Antarctica) were evaluated. To achieve this objective, the temporal behavior of the surface air temperature was analyzed, using data series at monthly resolution from 05 meteorological stations (period 1969-2019) located near the glacier, which were subjected to a trend (Mann Kendall, Linear Regression and Spearman Rho test), distribution (Cusum test) and teleconnections (El Niño Ocean Index, Southern Oscillation Index, Pacific Decadal Oscillation Index and Southern Annual Mode) analysis. Subsequently, the mass balance of Znosko glacier was determined by glaciological and geodesic method during the austral summer 2018-2019 and 2019-2020, using a network of 19 stakes installed on the glacier to record the surface ice mass loss in situ and compare the results derived from remote sensing (digital elevation models obtained from a drone flight). Finally, the distribution and thickness of the ice was estimated directly using a ground penetrating georadar (GPR) and indirectly with the Glabtop software (austral summer 2018-2019 and 2019-2020). The results show that the average summer temperatures on King George Island are above zero between December to March, registering a negative variation (-0.1 to -0.3 °C) during the period 2001-2019 (summer). The teleconnection analysis showed that the interannual variability of the air surface temperature is strongly correlated (direct and positive) with the Southern Annual Mode during autumn and to a lesser extent in spring and winter and with the mean annual temperature. The mass balance by glaciological method of this glacier was negative, registering losses of -590.7 mm.w.e (2018-2019) and -686.7 mm.w.e (2019-2020), while the geodetic method estimated a loss of -307.2 mm. w.e. The distribution of both modeled (Glabtop) and measured (GPR) ice thickness was heterogeneous along the Znosko glacier tongue, varying from a minimum value (0 m) along the edges to a maximum of 132 m (Glabtop) and 155 m (GPR) located in the accumulation zone and the central part of the glacier, respectively. In conclusion, it was observed that despite registering a temperature reduction during the summer between 2001-2019 on King George Island, there is a surface mass loss in Znosko glacier, possibly due to the reduction in solid precipitation (snow) that may influence the distribution of ice thickness in the future.
Description
Universidad Nacional Agraria La Molina. Escuela de Posgrado. Doctorado en
Recursos Hídricos
Keywords
Dinámica glaciar
Citation
Date
2024
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