Browsing by Author "Fuentealba Landeros, María Magdalena"

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    Comparing SPI and SPEI to detect different precipitation and temperature regimes in Chile throughout the last four decades
    (Elsevier Ltd, 2024) Meseguer Ruiz, Oliver; Serrano Notivoli, Roberto; Aránguiz Acuña, Adriana; Fuentealba Landeros, María Magdalena; Núñez Hidalgo, Ignacio; Sarricolea, Pablo; Garreaud, René
    Droughts are one of the main environmental challenges facing the world this century. The latitudinal and orographic characteristics of continental Chile leads different areas within it to experience very different regimes of precipitation and temperature, resulting in a wide variation in the occurrence and severity of droughts. Using the CR2Met 5 × 5 km resolution gridded monthly dataset covering the years from 1979 to 2019, we calculated the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evaporation Index (SPEI) of March and September at 3-, 6-, 9-, 12- and 24-months to: 1) relate them with different climate modes, and 2) determine their temporal evolution. We found that the Pacific Decadal Oscillation shows low positive correlations with SPI but no significant correlations with SPEI. The Multivariate El Niño Southern Oscillation shows different correlations in northern Chile, as well as El Niño 1 + 2 and the Antarctic Oscillation, for both SPI and SPEI. Both SPI and SPEI show negative (drier) trends in the north and center of Chile, while positive (wetter) trends appear in the south. SPEI shows stronger and more significant negative trends, influenced by the overall warming of the country. Warming trends are lower on the coast, so SPI could be a good indicator for coastal areas, while SPEI could be a good indicator for inland areas. Climate modes are useful for monthly and annual predictions, and by being a good drought predictor, they can help inform key public policies. These results are expected to help Chilean decision makers dealing with the challenges facing water management in the immediate future.
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    Influencia de los cambios de uso/cobertura del suelo y el clima en el ciclo del nitrógeno en dos lagos costeros de Chile central a partir de la colonización española
    (2019) Fuentealba Landeros, María Magdalena; Latorre H., Claudio; Pontificia Universidad Católica de Chile. Facultad de Ciencias Biológicas
    El “Antropoceno” se caracteriza por pertubaciones de origen humano que conllevan impactos globales. Por ejemplo, los cambios de uso/cobertura del suelo (LUCC) son conocidos por perturbar el ciclo del N a partir de la Revolución Industrial pero especialmente desde la Gran Aceleración (1950 CE) en adelante. Sin embargo, existen incertezas asociadas a la magnitud del impacto y su efecto acoplado con los cambios climáticos actuales (i.e megasequía, disminución de las precipitaciones) y acoplamientos con otros ciclos biogeoquímicos (e.g. ciclo del Carbono). Este impacto ha cambiado la disponibilidad de N en los ecosistemas terrestres y acuáticos y sus enlaces. Los sedimentos lacustres contienen información de las condiciones paleoambientales del lago y su cuenca en el momento en que se depositaron, y el análisis de los isótopos estables de N (δ15N) en los sedimentos permiten reconstruir los cambios en la disponibilidad de N a través del tiempo. En este trabajo, usamos una aproximación multiproxy que incluye análisis sedimentológicos, geoquímicos e isotópicos (δ15N, δ13C) de los sedimentos lacustres, columna de agua y suelo-vegetación de la cuenca y la reconstrucción delos LUCC entre 1975 y 2016 a partir de imágenes satelitales. El objetivo de esta tesis fue evaluar el rol de LUCC como principal control del ciclo del N en el sistema cuenca-lago durante las últimas centurias en Chile central. Nuestros principales resultados muestran que valores más positivos de δ15N en los sedimentos lacustres están relacionados con grandes aportes de N de la cuenca, que a su vez son mayores cuanto mayor la superficie agrícola y/o los pastizales, mientras que tanto las plantaciones forestales como los bosques favorecen la retención de nutrientes en la cuenca (lo que se ve reflejado en un δ15N más negativo). Esta tesis plantea un cambio de estado en la dinámica del N asociado a la introducción y expansión de las plantaciones forestales o bosques, los que retienen el Nitrógeno en las cuencas mientras que el clima juega un rol secundario.
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    Lake water response to the recent megadrought in the Andes of northern and central Chile (18°S-39°S)
    (2025) Fuentealba Landeros, María Magdalena; Sarricolea, Pablo; Meseguer-Ruiz, Oliver; Rivera, Andrés; Latorre Hidalgo, Claudio
    Human-induced climate change has led to increased intensity and frequency of dry years, known as megadroughts. These can generate scarcity of water availability which affects natural ecosystems, water security, and quality of life. Mountain lakes are major freshwater reservoirs that can aid in dealing with prolonged periods of hydrological stress. The lack of monitoring systems, however, is a major limitation for future planning. Here, we estimate changes in lake surface area to track the state of Andean lakes from northern and central Chile (18°S-39°S) to assess their response to a recent (2010–2022) megadrought. We mapped 40 high elevation lakes using Landsat satellite images from 1984 to 2021 and compared these results with the available climate data. Lakes in central Chile show a significative decrease in lake surface area up to 45%. A more diverse response occurs in the Altiplano, where several lakes show up to a 19% increase in area, possibly as a response to local factors such as increasing snow melt, especially in northernmost Chile. Further south, many altiplano lakes show a decreasing trend in surface area, which can be linked to variability of rainfall events, an increase in regional temperatures, or a combination of both. To further aid with land management and public policies, our results and database are also available as an online atlas. In the light of ongoing climate change, our results show that we are now at a critical moment regarding water resource management and evidence-based decisions will be key for conserving these threatened lake systems.