Browsing by Author "Sarricolea, Pablo"

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    Analysis of the Trends in Observed Extreme Temperatures in Mainland Chile Between 1966 and 2015 Using Different Indices
    (2019) Meseguer Ruiz, Oliver; Corvacho, Oscar; Tapia Tosetti, Alejandro; López Cepeda, José Fabián Cristóbal; Sarricolea, Pablo
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    Andean peatlands at risk? Spatiotemporal patterns of extreme NDVI anomalies, water extraction and drought severity in a large-scale mining area of Atacama, northern Chile
    (2023) Chavez, Roberto O.; Meseguer-Ruiz, Oliver; Olea, Matias; Calderon-Seguel, Matias; Yager, Karina; Isela Meneses, Rosa; Lastra, Jose A.; Nunez-Hidalgo, Ignacio; Sarricolea, Pablo; Serrano-Notivoli, Roberto; Prieto, Manuel
    In the Andes, multiple human and climatic factors threaten the conservation of bofedales, a type of high altitude peat forming wetland widely distributed in the tropical and subtropical Andes. In northern Chile, climate change and water extraction for industrial activities are among the most significant threats to these relevant socio-hydrological systems hosting indigenous pastoral communities. In this study, we present an integrated anal-ysis of Normalized Difference Vegetation Index (NDVI) anomalies, drought severity and water rights granted to industry to provide insight on the conservation status of bofedales, historical drivers of their transformation, and current threats. Using Landsat satellite imagery from 1986 to 2018, we identify spatio-temporal NDVI changes of 442 bofedales in one of the leading copper producing regions of the world. The NDVI time series analysis over 32 growing seasons was used to detect extreme anomalies, i.e. values outside the 95 % of the reference frequency distribution, indicating periods of extreme changes in the productivity of these high Andes wetlands. To evaluate the relationship between bofedales NDVI extreme periods to drought and continued water extraction activities, we combine a climate-based multi-temporal-scale drought index (SPEI) with the geospatial latitudinal distri-bution of water rights granted for extractive industries in the study area. Over the time period of analysis, the total amount of granted water rights increased 465 % from 1,201 l/s recorded before 1985 to 5,584 l/s in 2018. In the areas where the highest amount of water rights are concentrated, i.e. between 21.3 degrees S and 22.1 degrees S, "green" bofedales (NDVI>=0.23) are practically absent. NDVI of the austral summer (JFM) was highly correlated with the severity of drought occurring during the three months of the growing season peak. While our findings show bofedal productivity is mostly influenced by precipitation and temperature of the wet season (JFM) during the study period, results also raise questions regarding possible bofedal loss occurring over the previous 80 years prior to the satellite record, wherein water extraction activities have significantly increased according to official records.
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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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    General dry trends according to the standardized precipitation evapotranspiration index in mainland Chile
    (2024) Meseguer-Ruiz, Oliver; Serrano-Notivoli, Roberto; Nunez-Hidalgo, Ignacio; Sarricolea, Pablo
    Droughts are one of the main challenges affecting humanity in a global change context. Due to its spatial configuration, Chile experiences droughts of different severities, from arid to humid climates, ranging from sea level to elevations above 6,000 m above sea level (a.s.l.), but it is still unknown how this phenomenon behaves in distribution, duration and intensity. The goal of this study is to identify how droughts have affected the different climate regions of the country between 1979 and 2019. The Standardized Precipitation Evapotranspiration Index (SPEI), calculated for March and September, at the end of the humid season in the north and center-south of the country, respectively, and calculated at 3-, 6-, 9-, 12- and 24-month, allowed to determine the trends of the drought severity in a 5 x 5 km grid between 1979 and 2019. We found that negative and significant trends, indicating dry conditions, appear mainly in the Andes above 2,000 m a.s.l., where the main water reservoirs are located, affecting all climate types, except Mediterranean ones between 33 degrees S and 38 degrees S. The SPEI indicates general trends towards drier conditions across various elevations and climate types, with more pronounced negative trends in the north and central regions and some positive trends in the south. These trends suggest a significant impact on water availability, and highlight the need for focused policy initiatives to combat drought effects and manage water resources effectively. These findings are of main interest to Chile, one of the world's leading producers of lithium and copper, with both industries requiring substantial amounts of water for extraction and processing, demanding high water availability in a drier territory.
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    Heat beyond percentiles: exploring preterm birth risks in Santiago, Chile (1991–2019)
    (2026) Blanco, Estela; Conejeros Pavéz, José Daniel Hernan; González-Reyes, Álvaro; Rubilar, Paola; Sarricolea, Pablo; Smith, Pamela
    ObjectiveEvaluate the relationship between extreme heat in the week and month before delivery and risk of preterm birth (< 37 weeks’ gestation) using secondary data from Santiago, Chile.MethodsWe conducted a population-based cohort design using secondary information from birth records (1991–2019) and limited analysis to births in spring/summer months (n = 957,734). Temperature percentiles and the excess heat factor (EHF) were calculated for each of the 33 urban municipalities in Santiago using historical data. We derived 15 distinct heatwave metrics by combining three durations (2, 3, and 4 consecutive days) with five temperature thresholds: temperatures > 30 °C, the 90th, 95th, and 99th percentiles, and EHF. For each municipality, exposure (Yes or No) was assigned for each of these metrics in the week and month prior to delivery. We estimated Cox proportional hazard models adjusted for known confounders.ResultsPreterm birth occurred in 6% of births. There was spatial variability in extreme temperatures for the municipalities. Exposure to most heat wave metrics (≥ 2, ≥ 3, ≥ 4 days > 90th, 95th, and 99th percentile), did not relate to increased risk of preterm birth. Exposure to EHF for ≥ 2, ≥ 3, ≥ 4 days was associated with 1.02 (95% CI 1.00–1.04), 1.03 (95% CI 1.01–1.04), and 1.03 (95% CI 1.02–1.05), respectively. Exposure to ≥ 2, ≥ 3, ≥ 4 days of temperatures > 30 °C were associated with decreased hazards.ConclusionWe found evidence of increased risk of preterm birth, but only when evaluating exposure using EHF, a metric that considers acclimatization. Our results highlight the importance of understanding regional impacts of climate change on child health.
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    Heat vulnerability in a hyper-arid coastal conurbation: downscaled LST and socio-spatial analysis
    (2025) Sarricolea, Pablo; Baltazar, Alexis; Meseguer Ruiz, Oliver; Smith, Pamela; Picone, Natasha; Serrano Notivoli, Roberto; Vidal Paez, Paulina; Fuentealba, Magdalena; Thomas, Felipe
    Heat vulnerability is a critical issue for cities under climate change, especially in socially precarious contexts and extreme climates such as deserts. The Iquique–Alto Hospicio conurbation in northern Chile represents a distinctive case study due to its marked altitudinal contrasts and rapid urban expansion. This research focuses on assessing the Surface Urban Heat Island (SUHI) at its peak expression, during summer nighttime conditions, in order to spatialize heat vulnerability. A multi-scalar workflow was applied, beginning with long-term multitemporal analysis of land surface temperature at moderate resolution (2002–2023) and extending to high-resolution downscaling for five recent years (2019–2023) using bilinear resampling combined with robust regression techniques. A heat vulnerability index was then developed through principal component analysis (four components, ∼74% variance explained), complemented by a spatial cluster analysis based on Anselin’s Local Moran’s I, which delineated statistically significant hot-spots in Iquique’s historic core and in recently formalized social-housing districts on the Alto Hospicio plateau, as well as cold-spots along the affluent coastal seafront. The results confirm the presence of a strong nocturnal summer SUHI, largely coinciding with the most densely populated areas characterized by low-rise housing and limited green space. The local climate zone Compact low-rise and lightweight built forms were identified as the most vulnerable to heat. The study concludes that effective strategies should promote less dense building typologies while incorporating urban infrastructures that act as climate refuges across the conurbation. More broadly, the approach offers a transferable template for climate-resilient planning in data-scarce, arid coastal cities worldwide.
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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.
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    Population dynamics shifts by climate change: High-resolution future mid-century trends for South America
    (2023) Nunez-Hidalgo, Ignacio; Meseguer-Ruiz, Oliver; Serrano-Notivoli, Roberto; Sarricolea, Pablo
    Population dynamics and climate change are the main challenges for the 21st century, especially in South America. Human populations will increase their exposure to novel climatic conditions in their territories, entangling and complicating health and social problems. We analyze how socioeconomic and climatic future pathways will evolve in South America, a land with high climatic and social heterogeneity. We use the Koppen-Geiger climate classification, population growth, and climate projections for the most likely climate change scenarios for the 2050s based on the CHELSA dataset. We found that tropical and arid climates extend between 4.2%-2.5% and 2.6%-3.9%, replacing temperate climate zones, which will be reduced between 5.3%-4.5% for the Representative Concentration Pathways (RCP) 4.5 and 8.5 respectively. This implies a reduction of the Mediterranean, oceanic and polar climates. Population growth shows a significant relationship to increasing tropical and arid climates extension in almost all countries, meaning a higher exposure to more severe conditions for humans. This work opens up the chance of using possible guidelines to assist environmental management with key background information on expected climate types and population changes and address the potential effects of climate change on human settlements in the near future.
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    The 2010-2020 'megadrought' drives reduction in lake surface area in the Andes of central Chile (32 degrees - 36 degrees S)
    (ELSEVIER, 2021) Fuentealba, Magdalena; Bahamondez, Camila; Sarricolea, Pablo; Meseguer Ruiz, Oliver; Latorre, Claudio
    Study region: Andes central Chile (32 degrees S-36 degrees S) / Lakes
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    Urban climate simulation model to support climate-sensitive planning decision making at local scale
    (2024) Smith, Pamela; Blanco, Estela; Sarricolea, Pablo; Peralta, Orlando; Thomas, Felipe
    Urban planning, through design and land use allocation, affects urban climate dynamics and patterns at different atmospheric layers and spatial scales. Climate sensitive planning and design draws attention to the consideration of climate parameters for decision making. Seeking to contribute to the above, this research set out to identify the effect of urban design features (e.g., vegetation cover and construction density) on air temperature behavior. We conducted a case study, selected the Renca municipality located north-west Santiago, Chile, which represents a Mediterranean urban area affected by an intense daytime and nighttime urban heat island (UHI). We developed simple linear regression models to estimate air temperature per block in four different present and future scenarios: summer and winter and for day (16:00) and night (23:00). The urban-environmental variables were evaluated with the air temperature data series, measured in 21 points in the commune which were representative of urban and natural local climatic zones (LCZ). The results were evaluated and validated. We observed that variables such as vegetation, surface temperature or relative humidity are important explanatory factors for air temperature at the block scale in Renca across all four models. Models represent a tool that allows the evaluation of different design and urban planning alternatives at the scale of a city block, providing useful information for climate-sensitive decision-making.