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Ítem Restringido Improved spatial representation of precipitation and air surface temperature over highlands of the southern tropical Andes (Lake Titicaca region) during an austral summer using the WRF model(Elsevier, 2025-10-15) Llacza, A.; Paredes, J.; Llamocca, J.; Saavedra Huanca, Miguel; Fita, L.; Ruiz, C.; Junquas, C.Due to its complex topography, the Lake Titicaca region, located in the southern tropical Andes, presents great challenges for atmospheric modeling. This study aims to improve the representation of precipitation and air surface temperature using the Weather Research and Forecasting (WRF) model at high spatial resolution (2 km), during the austral summer of 2020. We conducted 11 experiments with different configurations of topography, land use, physical parameterizations, and lake surface temperature (LST). Each experiment was evaluated considering in-situ data from the Peruvian-Bolivian region and gridded precipitation products. For precipitation, the best configuration, with an average bias close to zero mm, includes using the GMTED2010 topography (not smoothed) and the land use data of Eva et al. (2004), along with the Purdue Lin microphysics and the Grell 3D cumulus scheme. For air temperature, the best configuration, which showed an average underestimation between 0 and − 0.5 °C, included the same topography and land use, along with the parameterization of the SENAMHI Operational Model (SOM), including the WRF Single Moment 3 microphysics and the Kain-Fritsch cumulus scheme. In the last experiment, the sea surface temperature (SST) was updated, resulting in an average LST increase of +1.8 °C over Lake Titicaca. This resulted in an increase in the precipitation bias (82.2 %) due to increased evaporation and convection over the lake and decreased southwestward moisture transport. These results highlight the sensitivity of the WRF model to parameterization choices and SST forcing data, emphasizing the importance of any changes in these variables.Ítem Acceso Abierto Forecasting austral summer precipitation along the western coast of South America (WCSA)(IOP Publishing, 2025-10-15) Sulca Jota, Juan Carlos; Takahashi, KenForecasting precipitation could help prevent flooding and drought disasters along the western coast of South America (WCSA), stretching from northern Peru to Ecuador. This study constructed a multiple linear regression (MLR) model to forecast precipitation anomalies with high spatial resolution across WCSA during the austral summer (December-January-February, DJF) for the period 1982–2023. The predictors of the MLR model are the central and eastern Pacific El Niño (C and E) and the central and east Pacific Intertropical Convergence Zone (CPITCZ and EPITCZ) indices. Furthermore, we readjusted the MLR model using forecasts from the Geophysical Fluid Dynamic Model (GFDL) model from the Seamless System for prediction and Earth System Research (SPEAR) called the GFDL-SPEAR (MLRGFDL-SPEAR) as predictors. The MLR model predicts DJF precipitation anomalies across WCSA because the E, CPITCZ and EPITCZ indices strongly correlate with DJF WCSA precipitation due to their influence on atmospheric circulation to trigger deep convection over far-eastern Pacific Ocean. The MLROBS model exhibits the highest performance over most WCSA (r > 0.6, p < 0.05), except along the coast of Ecuador and the Peru-Ecuador border by present high root mean square error values (above 20 mm month−1). The GFDL-SPEAR model provides more accurate forecasts of the DJF time series for the CPITCZ index than for the E and EPITCZ indices, due to Central Pacific ITCZ responses linearly to warm SST anomalies over western Pacific Ocean and it realistically simulates DJF precipitation patterns over Southern Pacific Ocean and Peru.Ítem Restringido Extreme Precipitation Events Associated with Summer Rains in the Western Slope of the Peruvian Andes Using a Numerical Modeling and Weather Radar Data: Case Studies(Springer, 2025-09-27) Moya Álvarez, Aldo Saturnino; Silva Vidal, Yamina; Villalobos Puma, Elver Edmundo; Saavedra Huanca, Miguel; Del Castillo Velarde, Carlos; Kumar, Shailendra; Valdivia Prado, Jairo MichaelPrecipitation forecasting is a challenge in general for any part of the world, but in Lima it is particularly difficult due to its unusual nature and the mechanisms that can generate it. So, it is of great interest to study the mechanisms that generate it when it exceeds historical averages. This work analyzes the synoptic and local circulation conditions that gave rise two precipitation events over the Rimac river basin, in order to characterize the physical processes related to those events. In the first case, the rain affected the city of Lima, while in the second case the precipitation occurred mainly in the upper part of the basin. In the investigation, surface precipitation measurements, weather radar and satellite information, as well as the WRF (Weather Research and Forecasting) model outputs were used. For the analysis of the synoptic-scale general circulation prevailing during both events, data from the Global Forecast System were used (GFS). As a result, the role played by the humid Eastern Amazon flow was confirmed, but in this case, the important role played by the local circulation of sea daytime breezes and its interaction with Amazon flow. Associated with this interaction, the presence of gravity waves and their importance in strengthening cloud systems was observed. At the same time, it was detected that the daytime sea breeze does not change direction during the night, as it generally does, but it stays from the sea towards the land, although somewhat weaker. The weakening of the Eastern flow from the Amazon was observed to be related to the retreat to the east of the ridge of the South Atlantic Anticyclone. Also, the importance of anticyclonic circulation at high levels over the region was confirmed. At the same time, it was found that the WRF model acceptably describes the mechanisms of formation of these events.Ítem Acceso Abierto Impact of Extreme Droughts on the Water Balance in the Peruvian–Ecuadorian Amazon Basin (2003–2024)(MDPI, 2025-10-23) Martínez Castro, Daniel; Espinoza, Jhan Carlo; Takahashi, Ken; Andrade, Miguel Octavio; Herrera, Dimitris A.; Centella-Artola, Abel; Apaéstegui Campos, James Emiliano; Armijos Cardenas, Elisa Natalia; Gutiérrez, Ricardo; Wongchuig, Sly; Silva Vidal, YaminaThis study assesses the impact of extreme droughts on the surface and atmospheric water balance of the Peruvian Amazon basin during 2003–2024. It extends previous work by incorporating multiple datasets for precipitation (CHIRPS, MSWEP, and ERA5) and evapotranspiration (ERA5, GLDAS, Amazon-Paca, and observations from the Quistococha flux tower) and comparing three drought indices: Maximum Cumulative Water Deficit (MCWD), Standardized Precipitation Evapotranspiration Index (SPEI), and self-calibrated Palmer Drought Severity Index (scPDSI). The study focuses on the Peruvian–Ecuadorian Amazon basin, particularly on the Amazon and Madre de Dios river basins, closing at Tamshiyacu and Amaru Mayu stations, respectively. The results confirm four extreme drought years (2004–2005, 2009–2010, 2022–2023, and 2023–2024) with major precipitation deficits in dry seasons and significant reductions in runoff and total water storage anomalies (TWSAs), physically manifesting as negative surface balances indicating net terrestrial water depletion and negative atmospheric balances reflecting reduced moisture convergence, with residuals signaling hydrological uncertainties. The study highlights significant imbalances in the water cycle during droughts and underscores the need to use multiple indicators and datasets to accurately assess hydrological responses under extreme climatic conditions in the Amazon basin.Ítem Acceso Abierto Impact of the Suspension of a Metallurgical Complex: SO₂ Analysis and Vegetation Restoration Through Remote Sensing(Wiley, 2025-09-24) Cano, Deyvis; Peñaloza, Richard; Cacciuttolo, Carlos; Mora Kuplich, Tatiana; Ramírez, Dámaso W.; Suárez-Salas, LuisSulfur dioxide (SO₂) pollution significantly threatens ecosystems and public health, particularly in highly industrialized regions. This study evaluates the impact of suspending activities at the La Oroya Metallurgical Complex (CMLO, by its Spanish acronym), one of the most relevant historical sources of SO₂ pollution in the Central Andes of Peru. Using remote sensing data (MODIS and Ozone Monitoring Instrument [OMI]), temporal and spatial trends in the normalized difference vegetation index (NDVI) and SO₂ concentrations were analyzed from 2000 to 2019. The results show an average reduction of 82.18% in SO₂ after the CMLO was stopped, accompanied by a significant positive increase in the NDVI trend (p < 0.05), which shows a recovery of the vegetation in surrounding areas. Vegetation regeneration showed marked spatial patterns to the southwest and southeast of the CMLO, influenced by the dispersion of pollutants through prevailing winds. However, the moderate relationship between the decrease in SO₂ and NDVI (R² = 0.10) suggests the influence of additional factors, such as the historical accumulation of heavy metals, water scarcity, and the specific characteristics of high Andean soils and vegetation.Ítem Acceso Abierto Urban heat island in the city of Brasilia: A multi-method analysis(Lublin University of Technology, 2025-10-01) Angeles-Vasquez, Roberto; Angeles-Suazo, Julio; Lavado Meza, Carmencita; Gutiérrez-Collao, Jairo Edson; Meza-Mitma, Pabel Mariano; Cruz-Cerron, Leonel de la; Flores Rojas, José Luis; Abi Karam, Hugo; Angeles-Suazo, NatalyCurrently, cities are experiencing increased urbanization and population density, leading to an increase in natural areas covered by paved and built-up areas, with a very rapid rate of urban expansion, as in the case of the capital Brasilia, Brazil. This has led to changes in local climates, increasing land surface temperature (LST) and causing an effect known as the Surface Urban Heat Island (SUHI) directly related to natural vegetation and urban and rural areas— which has become a major challenge for societies around the world due to its implications for public health and the environment. In this regard, the objective was to compare the temporal variation (2001-2016) of the SUHI in the Metropolitan Region of Brasilia (MRG) with MODIS satellite images, using the quantile method and Streutker method. The results indicate a maximum daytime SUHI in January (3.08 °C) and minimum in July (1.51 °C); the nighttime SUHI had maximums in July (2.36 °C) and minimums in April (1.72 °C). The Quantile-Streutker correlation ≈ 0.10, highlighting the usefulness of the quantile method for cities with different maximum temperature centers on a non-Gaussian surface.Ítem Acceso Abierto Rethinking the agricultural use of fire and its influence on the occurrence of wildfire in high Andean communities of Cusco, Peru(Elsevier, 2025-10-01) Alvarez, Sigrid; Martínez Grimaldo, Alejandra; Zubieta Barragán, Ricardo; Ccanchi, YersonThe use of fire in agriculture has been a fundamental practice since early human societies, playing a key role in land preparation, weed control, and soil fertility management. In the Peruvian Andes, fire remains widely employed by rural communities, despite strict legal prohibitions aimed at reducing wildfire occurrence. However, statistical evidence demonstrates that these punitive policies have failed to curb wildfires, which have instead increased in frequency. This study critically examines the agricultural use of fire in high Andean communities of Cusco, Peru, exploring its socio-cultural, economic, and environmental dimensions. Through ethnographic research and qualitative methodologies, the study identifies the motivations behind fire use, traditional fire-management practices, local and institutional perceptions, and community responses to wildfires. Findings reveal that fire is an indispensable agricultural tool, deeply embedded in rural livelihoods. The study also highlights the inadequacy of current fire management policies, which rely primarily on prohibition and emergency response without offering viable alternatives for smallholder farmers. To address this gap, the study proposes a paradigm shift in fire governance, advocating for a more inclusive and sustainable approach. Key recommendations include integrating prescribed burning, implementing incentive-based compensation schemes, and strengthening local governance structures. Additionally, the study underscores the necessity of qualitative research in informing quantitative analyses of wildfire occurrence, ensuring that policy interventions are grounded in local realities. Ultimately, rethinking the agricultural use of fire is not only an environmental concern but also a social and economic imperative for high Andean communities.Ítem Acceso Abierto Extreme Droughts in the Peruvian Amazon Region (2000–2024)(MDPI, 2025-06-10) Martínez Castro, Daniel; Takahashi, Ken; Espinoza, Jhan Carlo; Vichot-Llano, Alejandro; Andrade, Miguel Octavio; Silva Vidal, YaminaDroughts in the Amazon region are expected to increase in frequency and intensity, which would negatively affect the tropical forest, leading to a positive climate–forest feedback loop that could potentially result in the collapse of this ecosystem. In this study, extreme drought conditions were identified in the Peruvian Amazon region for the period 2000–2024 using the maximum cumulative water deficit (MCWD) index, which is related to the tropical forest water stress. The ERA5, CHIRPS, and MSWEP datasets were used to estimate precipitation, while ERA5 data were used for evapotranspiration. This study focuses on the specificities of droughts and the differences across study areas. Six study areas were specified, three of them located in the Loreto department (northern Peruvian Amazon), another centered in Moyobamba city (western Peruvian Amazon), another in Ucayali, in the central Peruvian Amazon, and the other in Madre de Dios (southern Peruvian Amazon). It was found that the drought events are more frequent and intense in the central and southern regions of the basin. Based on the combined effect of the regional severity of the drought and its spatial extent, estimated from averaging across study areas and precipitation datasets, we identified the hydrological years of 2023-24, 2022-23, 2009-10, and 2004-05 as extreme droughts and 2015-16 and 2006-07 as moderate droughts.Ítem Acceso Abierto Surface energy exchanges and stability conditions associated with convective intense rainfall events on the central Andes of Peru(Elsevier, 2025-06-15) Flores Rojas, José Luis; Guizado-Vidal, David A.; Valdivia Prado, Jairo Michael; Silva Vidal, Yamina; Villalobos-Puma, Elver; Suárez Salas, Luis; Mata-Adauto, Zenón; Abi Karam, HugoThis study presents an in-depth analysis of precipitation patterns, surface energy balance (SEB) components, and atmospheric vertical gradients (AVG) in the Huancayo Geophysical Observatory (HYGO) situated in an agricultural region inside the Mantaro valley within the central Andes of Peru, utilizing data from January 2018 to April 2022 and climatic-scale data from 1965 to 2018. Our findings reveal distinct daily and seasonal precipitation patterns, with peak occurrences in the late afternoon and early evening hours, and a pronounced seasonal variation aligning with dry and rainy periods. Analysis of 21 intense precipitation events linked to convective activity offers crucial insights for weather forecasting and disaster preparedness. These events were identified using in situ gauge pluviometers, the MIRA-35c vertical profiler radar and GPM-IMERG rainfall products. The turbulent energy fluxes: sensible (Qₕ) and latent (Qₑ) were estimated using the aerodynamic flux-gradient method and the ground heat flux to the surface was estimated with the scheme of Foken and Napo. Moreover, the study evaluates the efficacy of the Advanced Regional Prediction System (ARPS) model in analyzing turbulent energy fluxes during these events. A comparison with the bulk aerodynamic method indicated underestimations and overestimations by the ARPS model in predicting Qₕ and Qₑ, respectively, necessitating focused calibration and updates in satellite-derived data. Key observations include significant increases in Qe and horizontal momentum flux (𝜏) before convective precipitation events, marking them as potential precursor variables. Additionally, notable decreases in water vapor mixing ratio vertical gradient (WMVG) and Richardson number (RIN), along with increases in horizontal wind gradient (HWVG), suggest changes in surface moisture fluxes and boundary layer dynamics, crucial for convective rainfall initiation. This comprehensive analysis underscores the importance of understanding atmospheric dynamics for improved prediction and preparedness strategies in the face of climatic variability.Ítem Acceso Abierto A nationwide dataset of stable isotopes in meteoric and terrestrial water across Peru(Springer, 2025-07-12) Romero, Carol; Apaéstegui Campos, James EmilianoWater Stable Isotopes (δ18O, δ2H) are valuable tools for tracing sources and interactions in the water cycle, providing important information dedicated to understanding physical mechanisms related to global climate. Despite their significance, the topic of isotopic research in South America has been hindered by limited data. To address this gap, we launched a national-level water stable isotope dataset covering different water sources in Peru (WSI-PeruDB). The dataset contains curated in-house data and incorporates previously published records from various locations collected between 2000 and 2021. The WSIPeruDB dataset is composed of 489 water collection sites and allows a comprehensive use of the dataset by implementing standardized metadata templates containing essential geographical information such as latitude, longitude, and altitude (from sea level to 5000 m a.s.l), and sampling information such as sample type (e.g. groundwater, precipitation, river, spring, and others) and sampling frequency (e.g. biweekly, daily, monthly). The WSIPeruDB dataset is publicly available on Zenodo, facilitating access and use for the scientific community.Ítem Acceso Abierto Influence of local topographic structures on the atmospheric mechanisms related to the Andean-Amazon rainiest zone(Elsevier, 2025-03-16) Gutierrez-Villarreal, Ricardo A.; Junquas, Clémentine; Espinoza, Jhan Carlo; Baby, Patrice; Armijos Cardenas, Elisa NataliaThe Andes-Amazon transition region features critically important ecological services on the local, regional and global scales. This region is among the rainiest zones in the world, with rainfall rates of up to 7000 mm/year. However, the physical mechanisms leading to the existence of these “precipitation hotspots” remain poorly known. Here, we attempt to disentangle the controlling atmospheric mechanisms exerted by local topographic structures that started to uplift about 5–10 million years ago in response to the Nazca Ridge subduction, in the vicinity of the Quincemil hotspot, the most intense of them. We first use the Weather Research and Forecasting model to conduct sensitivity tests to planetary boundary layer parameterizations at 5 km horizontal grid spacing during the austral summer of 2012–13. After finding the most suitable configuration in terms of the diurnal cycle of rainfall intensity and extent, we further perform topographic sensitivity tests by reducing the Fitzcarrald Arch lowlands and, on top of it, by removing the Camisea mountain. The Fitzcarrald Arch deflects moisture flux towards Quincemil, while the Camisea mountain induces local vortical circulations that increase moisture transport, convergence and rainfall over Quincemil, ultimately controlling its location and intensity by up to 40 %. When reducing the height of the Andes in half, we find that it sustains the development of precipitation hotspots, accounting for up to 60 % of rainfall, by providing a mechanical forcing to increase regional-scale moisture fluxes. Such mechanisms dominate during nighttime, when rainfall peaks in the region, and might explain the existence of the rainiest zone in the Andes-Amazon transition.Ítem Acceso Abierto Multi-time scale analysis of the water level minima in Lake Titicaca over the past 103 years(Frontiers Media, 2025-05-06) Sulca Jota, Juan Carlos; Vuille, Mathias; Takahashi, Ken; Roundy, Paul; Dong, Bo; Mayta, Victor; Tacza, Jose; Apaéstegui Campos, James EmilianoLowest events in Lake Titicaca’s water level (LTWL) significantly impact local ecosystems and the drinking water supply in Peru and Bolivia. However, the hydroclimatic mechanisms driving extreme lake-level lowstands remain poorly understood. To investigate these low lake-level events, we analyzed detrended monthly LTWL anomalies, sea Surface temperature (SST) datasets covering the period 1921–2023. ERA5 reanalysis covers the period 1940–2023. A multiple linear regression model was developed to compute detrended LTWL anomalies, excluding multidecadal and residual components. Interdecadal Pacific Oscillation (IPO) and Pacific Decadal Oscillation (PDO) índices were also analyzed for the same period. Results indicate that 25% of all LTWL minima events have a short duration of <5 months, while the remaining 75% of all events have a long duration of more than 9 months, respectively. All long-lived LTWL minima events are associated with reduced moisture flow from the Amazon basin toward Lake Titicaca, but the large-scale forcing varies with the phase change of the decadal component in the 11–15 years band of the PDO (PDO11–15 years). Under warm PDO11–15 years phases, LTWL minima are driven by an enhanced South American low-level jet (SALLJ) caused by warm SST anomalies over the eastern Pacific Ocean. Warm SST anomalies over tropical North Atlantic and central Pacific cold events, which reinforce the cold PDO11–15 years phases, driving long-lived LTWL minima through the reduction of SALLJ. Conversely, long-lived LTWL minima events under neutral PDO11–15 years phases are caused by westerly flow anomalies confined to the Peruvian Altiplano. Therefore, PDO and IPO do not drive long-lived LTWL minima events because their relationship does not remain consistent over time. In conclusion, long-lived LTWL minima events exhibit a regional nature and are not driven by the PDO or IPO, as LTWL shows no consistent relationship with these decadal SST modes over time.Ítem Acceso Abierto Dynamics and patterns of land cover change in the Piura River Basin (Peruvian Pacific slope and coast) in the last two decades(Frontiers Media, 2025-05-15) Castillón, Fiorela; Rau, Pedro; Bourrel, Luc; Frappart, FrédéricLand use and land cover (LULC) changes in the Piura River Basin, Peru, were analyzed from 2001 to 2022 using global MODIS and ESA-CCI datasets harmonized into six major land cover classes (Forest, Non-Forest Vegetation, Cropland, Bare Soil, Water and Urban) for comparative analysis. Pearson correlation analyses with hydroclimatic variables, including precipitation (PP), maximum (Tx) and minimum (Tn) temperatures, and El Niño Southern Oscillation (ENSO) indices (Eastern Pacific, Central Pacific, and Coastal El Niño), complemented the intensity analysis to explore environmental drivers. The analyses focused on the lower-middle and upper basin regions during wet (December-May) and dry (June-November) seasons. MODIS detected more dynamic LULC transitions, with 32.8% of pixels showing changes, compared to 6.8% detected by the ESA-CCI product. These differences reflect the distinct sensitivities of MODIS and ESA-CCI products to short-term fluctuations and long-term variations, respectively. Specifically, MODIS identified higher annual change intensities and more frequent transitions, especially in the upper basin, whereas ESA-CCI provided a more conservative view of land cover trends. Both datasets consistently indicated a decline in cropland areas and an increase in bare soil, suggesting agricultural degradation and potential desertification processes. Correlation analyses revealed significant relationships between vegetation dynamics and climatic variables, notably ENSO events, precipitation, and temperature extremes, highlighting how hydroclimatic factors drive vegetation variability. The upper basin experienced notable urban expansion and deforestation dynamics linked to temperature fluctuations and intensified El Niño events, particularly after 2011. These findings underscore the critical influence of climatic extremes and human activities on vegetation dynamics, emphasizing the need for integrated, adaptive management strategies to mitigate desertification in lowlands and enhance forest conservation in highlands.Ítem Acceso Abierto A description of existing operational ocean forecasting services around the globe(Copernicus Publications, 2025-06-02) Cirano, Mauro; Alvarez-Fanjul, Enrique; Capet, Arthur; Ciliberti, Stefania; Clementi, Emanuela; Dewitte, Boris; Dinápoli, Matias; Serafy, Ghada El; Hogan, Patrick; Joseph, Sudheer; Miyazawa, Yasumasa; Montes Torres, Ivonne; Narvaez, Diego A.; Regan, Heather; Simionato, Claudia G.; Smith, Gregory C.; Staneva, Joanna; Tanajura, Clemente A. S.; Thupaki, Pramod; Urbano-Latorre, Claudia; Veitch, JenniferPredicting the ocean state in support of human activities, environmental monitoring, and policymaking across different regions worldwide is fundamental. To properly address physical, dynamical, ice, and biogeochemical processes, numerical strategies must be employed. The authors provide an outlook on the status of operational ocean forecasting systems in eight key regions including the global ocean: the West Pacific and Marginal Seas of South and East Asia, the Indian Seas, the African Seas, the Mediterranean and Black Sea, the North East Atlantic, South and Central America, North America (including the Canadian coastal region, the United States, and Mexico), and the Arctic. The authors initiate their discussion by addressing the specific regional challenges that must be addressed and proceed to discuss the numerical strategy and the available operational systems, ranging from regional to coastal scales. This compendium serves as a foundational reference for understanding the global offering, demonstrating how the diverse physical environment – ranging from waves to ice – and the biogeochemical features besides ocean dynamics can be systematically addressed through regular, coordinated prediction efforts.Ítem Restringido The Earth alignment principle for artificial intelligence(Nature Research, 2025-03-28) Gaffney, Owen; Luers, Amy; Carrero-Martinez, Franklin; Oztekin-Gunaydin, Berna; Creutzig, Felix; Dignum, Virginia; Galaz, Victor; Ishii, Naoko; Larosa, Francesca; Leptin, Maria; Takahashi, KenAt a time when the world must cut greenhouse gas emissions precipitously, artificial intelligence (AI) brings large opportunities and large risks. To address its uncertain environmental impact, we propose the ‘Earth alignment’ principle to guide AI development and deployment towards planetary stability.Ítem Acceso Abierto ENSO Diversity Regulation of the Impact of MJO on Extreme Snowfall Events in the Peruvian Andes(Wiley, 2025-03-25) Sulca Jota, Juan CarlosExtreme snowfall events (ESEs) in the Peruvian Andes (10°–18.4° S, > 4000 m) result in considerable economic losses. Despite their importance, how El Niño-Southern Oscillation (ENSO) diversity modulates the impact of the Madden–Julian Oscillation (MJO) on ESEs in the Peruvian Andes remains unexplored. Daily ERA5 reanalysis data from 1981 to 2018 were analysed. This study examines 16 ESEs. A bandpass filter with a 20–90-day range was applied to isolate the intraseasonal component of the daily anomalies. Additionally, time series data from the real-time multivariate MJO (RMM) index and Eastern and Central ENSO (E and C) indices were utilised. Composites were performed to describe the atmospheric circulation patterns related to ESEs in the Peruvian Andes under neutral, El Niño and La Niña conditions in the central and eastern Pacific Ocean. Under non-ENSO conditions, the MJO alone does not trigger ESEs in the Peruvian Andes during the DJF season. The absence of a well-organised convection system over the Peruvian Andes prevents ESEs. Conversely, during the JJA season, MJO Phases 5, 6 and 7 induce ESEs in the southern Peruvian Andes by enhancing moisture flux from the east through the equatorward propagation of an extratropical Rossby wave train that crosses South America and reaches the Altiplano region. In terms of ENSO diversity, the combined effects of the Central La Niña and MJO Phases 6 + 7 induce ESEs across the Western Cordillera of the southern Peruvian Andes during the DJF season. During austral winter, the interaction between the Central El Niño and MJO Phases 8 + 1, Eastern El Niño and MJO Phases 2 + 3, and Eastern La Niña and MJO Phases 8 + 1 induce ESEs across the Peruvian Andes.Ítem Restringido The South American Climate During the Last Two Millennia(Oxford University Press, 2024-12-11) Flores-Aqueveque, V.; Arias, P. A.; Gómez-Fontealba, C.; González-Arango, C.; Apaéstegui Campos, James Emiliano; Evangelista, H.; Guerra, L.; Latorre, C.Paleoclimate reconstructions are essential for understanding the dynamics of the climate system and its past variations. By utilizing climate-dependent proxies, these reconstructions provide a comprehensive perspective on climatic variations that extend far beyond the limited scope of instrumental records, spanning centuries to millennia. Particularly, proxy-based reconstructions for the last two millennia provide valuable insights into natural climate variability during the preindustrial era and the anthropogenic influence on current climate change. As a result, paleoclimate studies are also critical for interpreting climate projections in the context of anthropogenic forcing. South America, with its vast and diverse climate conditions, is a region rich in high-resolution paleoclimate records, including marine, lacustrine, and fjord sediments, speleothems, ice cores, tree rings, glacial and aeolian deposits, archaeological evidence, and historical documents, among others, all of which capture past climate changes. However, despite numerous paleoclimate reconstructions conducted across the continent and significant advances in understanding its past climate, substantial research gaps remain. These gaps are particularly evident in understudied regions and poorly understood phenomena, hindering a comprehensive understanding of climate variability at both regional and continental scales. To advance paleoclimatic research in South America, future efforts should prioritize (a) the collection of high-resolution records from key locations, (b) the integration of diverse proxies and innovative methodologies, (c) enhancing our understanding of climate-proxy relationships, and (d) developing new proxy calibrations. Collaboration with local communities and indigenous peoples and adopting interdisciplinary approaches will be vital in driving the field forward.Ítem Acceso Abierto Estimación de lluvias extremas mediante un enfoque de análisis regional y datos satelitales en Cusco, Perú(Instituto Mexicano de Tecnología del Agua, 2024-09-01) Aragón, Luis; Lavado-Casimiro, Waldo; Montesinos, Cristian; Zubieta Barragán, Ricardo; Laqui, WilberLa frecuencia y magnitud de los eventos climáticos extremos de precipitación han aumentado de forma significativa en varios países del mundo, incluido Perú. Estos hechos causan pérdidas económicas y humanas, especialmente en países en vías de desarrollo. La información y metodologías que permitan prevenir o diseñar estrategias para afrontarlas son escasas o inexistentes. El objetivo de esta investigación fue analizar la capacidad del producto satelital IMERG (Integrated MultisatellitE Retrievals) del satélite GPM (Global Precipitation Measurement) y datos observados a partir de estaciones meteorológicas mediante un enfoque mixto para estimar la distribución de lluvias extremas en la región del Cusco, ubicado al sur del Perú. Este enfoque mixto aprovechó las ventajas que ofrecen ambas fuentes de información, como es la solidez de los datos observados a lo largo de varios años y la resolución temporal horaria del producto satelital. La metodología se basó en una curva de crecimiento de cada región homogénea, factor de corrección y parámetros que estiman la función intensidad y duración para toda la región Cusco. Los resultados se evaluaron mediante validación cruzada entre los valores de precipitación diaria obtenidos del producto IMERG, enfoque mixto y precipitación observada para periodos de retorno de 2, 5, 10, 20, 50, 100, 200, 500 y 1 000 años. Los resultados sugieren que la combinación de datos observados de lluvia y del satélite IMERG puede ser una alternativa para estimar lluvias extremas en la región Cusco.Ítem Acceso Abierto Atmospheric aerosols and air quality in the 2022 dry season in Huancayo-Perú(Universidade Federal do Rio de Janeiro, 2024-05-15) Angeles Vasquez, Roberto; Angeles Suazo, Julio Miguel; Abi Karam, Hugo; Flores Rojas, José Luis; Suarez Salas, Luis; Lavado-Meza, Carmencita; Angeles Suazo, Nataly; Boza Ccora, Fernando; De la Cruz-Cerron, Leonel; Zarate Quiñones, RosaThis work presents results of Aerosol Optical Depth (AOD) and Direct Radiative Force (DRF) at the top of the atmosphere (TOA), obtained during monitoring campaigns carried out at the Huancayo Observatory of the Geophysical Institute of Peru (OH-IGP ) in April and August 2022. In these campaigns, a Sun CIMEL photometer was used to measure the microphysical and optical properties of aerosols at wavelengths ranging from 340 to 1020 nm, and a low-cost Purple-air sensor to quantify the concentration of material particulate (PM), in fine and coarse modes. The AOD results indicated values in the range 0.06-0.22. The daily averages of PM2.5 and PM10 did not exceed Peru’s current Environmental Quality Standards (50 μg/m³ and 100 μg/m³). The air quality index (AQI) calculated for PM2.5 and PM10 was classified as good. On some days during the campaigns, the air quality was classified as moderate. These results contribute to a better understanding of the current climatic conditions of the Peruvian Altiplano.Ítem Acceso Abierto Latitudinal and temporal distribution of aerosols and precipitable water vapor in the tropical Andes from AERONET, sounding, and MERRA‑2 data(Nature Research, 2024-01-09) Cazorla, María; Giles, David M.; Herrera, Edgar; Suárez Salas, Luis; Estevan, Rene; Andrade, Marcos; Bastidas, ÁlvaroThe aerosol and precipitable water vapor (PW) distribution over the tropical Andes region is characterized using Aerosol Robotic Network (AERONET) observations at stations in Medellin (Colombia), Quito (Ecuador), Huancayo (Peru), and La Paz (Bolivia). AERONET aerosol optical depth (AOD) is interpreted using PM₂.₅ data when available. Columnar water vapor derived from ozone soundings at Quito is used to compare against AERONET PW. MERRA-2 data are used to complement analyses. Urban pollution and biomass burning smoke (BBS) dominate the regional aerosol composition. AOD and PM₂.₅ yearly cycles for coincident measurements correlate linearly at Medellin and Quito. The Andes cordillera’s orientation and elevation funnel or block BBS transport into valleys or highlands during the two fire seasons that systematically impact South America. The February–March season north of Colombia and the Colombian-Venezuelan border directly impacts Medellin. Possibly, the March aerosol signal over Quito has a long-range transport component. At Huancayo and La Paz, AOD increases in September due to the influence of BBS in the Amazon. AERONET PW and sounding data correlate linearly but a dry bias with respect to soundings was identified in AERONET. PW and rainfall progressively decrease from north to south due to increasing altitude. This regional diagnosis is an underlying basis to evaluate future changes in aerosol and PW given prevailing conditions of rapidly changing atmospheric composition.