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Item Restricted 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.Item Open Access 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.Item Restricted 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.Item Open Access 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.Item Open Access 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.Item Open Access 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.Item Open Access Hydrometeors Distribution in Intense Precipitating Cloud Cells Over the Earth’s During Two Rainfall Seasons(Springer, 2024-01-25) Kumar, Shailendra; Flores Rojas, José Luis; Moya Álvarez, Aldo Saturnino; Martínez Castro, Daniel; Silva Vidal, YaminaIn the present study, we used attenuated corrected radar refectivity factor (Zₑ) and rain-drop size distribution (DSD) to investigate the hydrometeors distribution in the intense precipitating cloud cells (PCCs) from precipitation radar (PR) onboard on Global Precipitation Measurement (GPM). The DSD parameters consist of two variables, namely, mass-weighted mean diameter (Dₘ) in mm and normalized scaling parameters for hydrometeors concentration (Nw) in mm⁻¹ m⁻³. We defned two types of PCCs, which are the proxies for the intense rainfall events. First PCC is termed as Cumulonimbus Towers (CbTs), which consist of Zₑ> =20 dBZ at 12 km altitude, and its base height must be less than 3 km altitude. We also defned intense convective clouds (ICCs), which consist of Zₑ>30 (40) dBZ at 8 km (3 km), respectively, and are termed as ICC8 and ICC3, respectively. The spatial distribution reveals that continental areas consist of a higher frequency of CbTs and ICC8s compared to oceanic areas, whereas ICC3s are uniformly distributed over tropical land and oceanic areas. The DSD parameters reveal that intense PCCs have larger hydrometeors (Dₘ), whereas weaker (less Zₑ) vertical profles consist of higher concentration (Nw) of smaller hydrometeors (Dₘ). Land consists of larger hydrometeors (Dₘ) compared to oceanic areas, and diferences are higher in liquid phase regimes compared to mixed phase regimes. The vertical profles of Zₑ, Dₘ and Nw are showing the higher regional diferences among the diferent land-based areas, compared to various tropical ocean basins. Western Himalaya Foothills and Sierra De Cordoba consist of the strongest vertical profles with the largest Dₘ on the Earth’s áreas during JJAS and DJFM months, respectively.Item Open Access Future changes of precipitation types in the Peruvian Andes(Nature Research, 2024-09-30) Llactayo, Valeria; Valdivia Prado, Jairo Michael; Yarleque, Christian; Callañaupa, Stephany; Villalobos‑Puma, Elver; Guizado, David; Alvarado‑Lugo, RobertIn high-altitude regions, such as the Peruvian Andes, understanding the transformation of precipitation types under climate change is critical to the sustainability of water resources and the survival of glaciers. In this study, we investigate the distribution and types of precipitation on a tropical glacier in the Peruvian Central Andes. We utilized data from an optical-laser disdrometer and compact weather station installed at 4709 m ASL, combined with future climate scenarios from the CMIP6 project, to model potential future changes in precipitation types. Our findings highlight that increasing temperatures could lead to significant reductions in solid-phase precipitation, including snow, graupel and hail, with implications for the mass balance of Andean glaciers. For instance, a 2 °C rise might result in less than 10% of precipitation as solid, in regard to the present day, transforming the hydrological processes of the region. The two future climate scenarios from the CMIP6 project, SSP2-4.5 and SSP5-8.5, offer a broad perspective on potential climate outcomes that could impact precipitation patterns in the Andes. Our study underscores the need to revisit and expand our understanding of high-altitude precipitation in the face of climate change, paving the way for improved water resource management strategies and sustainable glacier preservation efforts in these fragile ecosystems.Item Open Access Chemical composition and trajectories of atmospheric particles at the Machu Picchu Peruvian Antarctic scientific station (62.09° S, 58.47° W)(Universidad Autónoma de México, 2024-04-25) Álvarez-Tolentino, Daniel; Suárez Salas, Luis; Pomalaya-Valdez, José; Barja, BorisAntarctica is a remote and relatively pristine region, but the regional transport of aerosols may be a source of pollution, especially in the Antarctic Peninsula. Few studies have characterized atmospheric aerosols and evaluated the contribution of their emission sources. The Peruvian Antarctic research station Machu Pichu (ECAMP, by its Spanish acronym) is located on King George Island in the Antarctic Peninsula. During February 2020, atmospheric particulate mass (PM ₁₀ and PM ₂.₅) was sampled and analyzed to characterize its elemental composition and was supplemented by measurements of equivalent black carbon and aerosol size distributions. Chemical elements were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), multivariate techniques, and enrichment factors. The most abundant elements in PM ₁₀ and PM ₂.₅ were Na, Fe, Mg, and Si, with the most important local sources being marine (Na, Mg, Mn, Ca) and crustal (Fe, Al, P). Sources of weathering (Ba and Si) from glacial thawing and sources of combustion linked to the use of oil (V) and emission of black carbon were recorded. Air mass back-trajectory analysis using the HYSPLIT model helped identify external sources of particulate matter in the air masses reaching the ECAMP site. Overall, this study supports the growing evidence of the anthropogenic impact of distant and local sources on the white continent.Item Open Access Analysis of vertical flow velocity and suspended sediment concentration profiles in Tumbes River during El Niño and La Niña events. [Análisis de los perfiles verticales de velocidad de flujo y de concentración de sedimentos en suspensión medidos en el río Tumbes durante El Niño y La Niña](LACCEI, Latin American and Caribbean Consortium of Engineering Institutions, 2024-07) Mendoza Sulcaray, Renzo Dampier; Campaña Toro, Roberto Luis; Armijos Cárdenas, Elisa Natalia; Morera Julca, Sergio ByronLa región de Tumbes, ubicada en el norte de Perú, se ve afectada por los fenómenos climáticos de El Niño y La Niña. El Niño provoca una intensa precipitación, lo que resulta en altos flujos de agua y generación de sedimentos. En cambio, La Niña conlleva déficits de precipitación, resultando en flujos líquidos más bajos y cargas de sedimentos menores en comparación con El Niño. El objetivo de este estudio es analizar los perfiles verticales de velocidad de flujo y la concentración de sedimentos en suspensión medidos en la estación hidrométrica El Tigre en el río Tumbes, ubicado a 50 km río arriba del estuario del Océano Pacífico, durante los períodos de inundación en los eventos de El Niño de 2017 y La Niña de 2018. Los perfiles verticales de velocidad de flujo, medidos utilizando un medidor de corriente de efecto Doppler, se modelaron aplicando la distribución teórica de velocidad del tipo log-wake. Se ajustaron parámetros como la velocidad de corte, la distancia desde el lecho donde teóricamente la velocidad del perfil de flujo se vuelve cero y el parámetro de estela. Los perfiles verticales de concentración de sedimentos en suspensión se modelaron utilizando la distribución teórica resultante de la distribución parabólico-lineal del coeficiente de mezcla de fluidos. Se ajustaron parámetros, incluyendo el diámetro medio de los sedimentos en suspensión y la concentración de sedimentos en suspensión de referencia cerca del lecho. El estudio concluyó que los perfiles verticales de velocidad de flujo y concentración de sedimentos en suspensión registrados durante el evento de El Niño de 2017 y el evento de La Niña de 2018 coincidieron razonablemente con la distribución teórica de velocidad del tipo log-wake y la distribución teórica de concentración de sedimentos en suspensión resultante de la distribución parabólico-lineal del coeficiente de mezcla de fluidos. Utilizando los modelos ajustados, se estimó que los tamaños medios de los sedimentos en suspensión calculados para el evento de El Niño de 2017 (62 a 132 µm) fueron aproximadamente 2 veces mayores que los calculados para La Niña de 2018 (25 a 67 µm), y que las concentraciones de sedimentos en suspensión de referencia en el lecho calculadas para el evento de El Niño de 2017 (254 a 1766 mg/l) fueron aproximadamente 7 veces mayores que las calculadas para La Niña de 2018 (95 a 250 mg/l).Item Open Access Modern anthropogenic drought in Central Brazil unprecedented during last 700 years(Nature Research, 2024-02-26) Misailidis Stríkis, Nicolas; Silva Melo Buarque, Plácido Fabrício; Cruz, Francisco William; Bernal, Juan Pablo; Vuille, Mathias; Tejedor, Ernesto; Simões Santos, Matheus; Harumi Shimizu, Marília; Ampuero, Angela; Du, Wenjing; Sampaio, Gilvan; Reis Sales, Hamilton dos; Campos, José Leandro; Toshie Kayano, Mary; Apaéstegui Campos, James Emiliano; Fu, Roger R.; Cheng, Hai; Edwards, R. Lawrence; Chavez Mayta, Victor; Silva Francischini, Danielle da; Zezzi Arruda, Marco Aurélio; Felipe Novello, ValdirA better understanding of the relative roles of internal climate variability and external contributions, from both natural (solar, volcanic) and anthropogenic greenhouse gas forcing, is important to better project future hydrologic changes. Changes in the evaporative demand play a central role in this context, particularly in tropical areas characterized by high precipitation seasonality, such as the tropical savannah and semi-desertic biomes. Here we present a set of geochemical proxies in speleothems from a well-ventilated cave located in central-eastern Brazil which shows that the evaporative demand is no longer being met by precipitation, leading to a hydrological deficit. A marked change in the hydrologic balance in central-eastern Brazil, caused by a severe warming trend, can be identified, starting in the 1970s. Our findings show that the current aridity has no analog over the last 720 years. A detection and attribution study indicates that this trend is mostly driven by anthropogenic forcing and cannot be explained by natural factors alone. These results reinforce the premise of a severe long-term drought in the subtropics of eastern South America that will likely be further exacerbated in the future given its apparent connection to increased greenhouse gas emissions.Item Open Access Urban heat island and increase in temperature on urban roads in Huancayo/Peru [Isla de calor urbano e incremento de temperatura en vías urbanas en Huancayo/Perú](LACCEI, Latin American and Caribbean Consortium of Engineering Institutions, 2024-07) Angeles Vasquez, Roberto; Angeles Suazo, Julio; Flores Rojas, José Luis; Boza Ccora, Fernando; Angeles Suazo, Nataly; Suarez Salas, Luis; Abi Karam, HugoLa rápida urbanización de las ciudades está cambiando el clima local, lo que genera altas temperaturas y entornos urbanos densos y difíciles, carentes de agua y vegetación[1]. La presente contribución estima la intensidad de Isla de Calor Urbano Superficial (ICUS) durante el periodo 2001 – 2022 para el Área Metropolitana de Huancayo (AMH), Perú. Se cuantificó formación de la Isla de Calor Urbano Superficial, a partir de 2 métodos: el primero es el método de Streutker, el cual ajusta la temperatura superficial del suelo (LST) (superficie urbana y rural) a una superficie Gaussiana. El segundo, método de cuantil propuesto por José Flores, usa la diferencia entre el cuantil 0.95 de LST del área urbana y la mediana del LST del área rural. Ambos métodos usan data de sensoramiento remoto de LST a 0.05⁰ de resolución, obtenido del sensor MODIS a bordo del satélite TERRA y AQUA. Para el AMH, durante los periodos diurnos, la intensidad de ICUS en marzo y julio representan el máximo y mínimo incremento. El periodo nocturno, presentó valores máximo y mínimo en agosto y diciembre respectivamente. En general se consiguió mostrar las principales causas del incremento de temperatura superficial es el pavimento asfaltado, donde la temperatura puede ser hasta 60 °C. Por ello es importante proponer medidas de mitigación como construcciones y pavimentos sostenible que ayuden a mitigar el incremento de temperatura superficial. Así como la importancia de considerar la Floresta o plantaciones vegetales en un diseño o zonificación urbana.Item Open Access GC Insights: Lessons from participatory water quality research in the upper Santa River basin, Peru(Copernicus Publications, 2024-06-27) Rangecroft, Sally; Clason, Caroline; Dextre, Rosa Maria; Richter, Isabel; Kelly, Claire; Turin, Cecilia; Grados-Bueno, Claudia V.; Fuentealba, Beatriz; Camacho Hernandez, Mirtha; Morera Julca, Sergio Byron; Martin, John; Guy, John AdamHere we share four key lessons from an interdisciplinary project (Nuestro Rio) that gathered community perspectives on local water quality in the Santa River basin (Peru) utilising a digital technological approach where we collected data via a novel photo elicitation app, supported by a field work campaign. The lessons explored in this article provide insights into challenges and opportunities for researchers considering developing technological tools for encouraging participation and engagement in marginalised communities.Item Open Access Dynamic atmospheric mechanisms associated with the diurnal cycle of hydrometeors and precipitation in the Andes–Amazon transition zone of central Peru during the summer season(Springer, 2024-04-04) Villalobos-Puma, Elver; Morales, Annareli; Martinez-Castro, Daniel; Valdivia Prado, Jairo Michael; Lavado-Casimiro, Waldo; Santiago, AlexzanderThe diurnal cycle of total hydrometeor availability and its associated patterns of atmospheric circulation is studied over a connected Andes–Amazon (A–A) system in the central region of Peru during the summer season. Surface precipitation depends on the amount of hydrometeors that occur in the atmosphere and its atmospheric dynamics. Hydrometeors and the precipitation efficiency index were estimated using radar of the core satellite of the GPM system (N-GPM) for the period 2014–2022. The atmospheric dynamics were analyzed using the regional Weather Research and Forecasting (WRF) model. According to the results, the Andes mountain range produces precipitation at a surface level more efficiently during the afternoon and early evening hours (12–19 LT) due to the convergence of the thermal mesoscale circulations transporting moisture fluxes from the east and west. Both generate convective multicells along the Andes mountain range. The circulation from the west intensifies during the day, causing the displacement of the chain of convective multicells towards the east and producing hydrometeors and intense precipitations in the inter-Andean valleys. The A–A transition zone is more efficient in producing precipitation during the early hours of the day (00–07 LT) due to an increase in the northern circulation associated with the low-level jets and a change in the magnitude of the horizontal winds. Northerly winds enter the A–A transition zone with increased intensity and leave with reduced intensity. This mechanism is driven by the effect of the topographical barrier and the masses of cold air located in high areas on the eastern flank of the Andes. These factors generate significant updrafts and, therefore, the formation of storm clouds with high concentrations of hydrometeors and precipitation on the surface.Item Open Access Observational characterization and empirical modeling of global, direct and diffuse solar irradiances at the Peruvian central Andes(Frontiers Media, 2024-08-12) Fashé-Raymundo, Octavio; Flores-Rojas, José Luis; Estevan-Arredondo, René; Giráldez-Solano, Lucy; Suárez Salas, Luis; Sanabria-Pérez, Elias; Abi Karam, Hugo; Silva Vidal, YaminaThe present study aims to comprehensively assess the solar irradiance patterns in the western zone of the Mantaro Valley, a region of ecological and agricultural significance in the central Peruvian Andes. Leveraging radiation data from the Baseline surface Radiation Network (BSRN) sensors located in the Huancayo Geophysical Observatory (HYGO-12.04°S,75.32°W, 3350 masl) spanning from 2017 to 2022, the research delves into the seasonal variations and trends in surface solar irradiance components. Actually, the study investigates the diurnal and seasonal variations of solar irradiance components, namely diffuse (EDF), direct (EDR), and global (EG) irradiance. Results demonstrate distinct peaks and declines across seasons, with EDR and EDF exhibiting opposing seasonal trends, influencing the overall variability in, EG. Peaks of, EG occurred in spring (3.32 MJ m⁻² h⁻¹ at noon), particularly during October (24.14 MJ m⁻² day⁻¹), probably associated with biomass-burning periods and heightened aerosol optical depth (AOD). These findings highlight the impact of biomass-burning aerosols on solar radiation dynamics in the region. In general, the seasonal variability of, EG on the HYGO is lower than that observed in other regions of South America at higher latitudes and reach its maximums during spring months. Moreover, the research evaluates various irradiation models to establish correlations between sunshine hours, measured with a solid glass sphere heliograph, and, EG and EDF at different time scales, showing acceptable accuracy to predict. In addition, the sigmoid logistic function emerges as the most effective in correlating the hourly diffuse fraction and the hourly clearness index, showcasing superior performance compared to alternative functions and exhibiting strong statistical significance and providing valuable insights for future solar radiation forecasting and modeling efforts. This study offers valuable insights for solar radiation forecasting and modeling efforts, emphasizing the importance of interdisciplinary research for solar power generation, sustainable development and climate resilience in mountainous regions like the Peruvian Andes.Item Restricted Atmospheric black carbon observations and its valley-mountain dynamics: Eastern cordillera of the central Andes of Peru(Elsevier, 2024-08-15) Villalobos-Puma, Elver; Suárez Salas, Luis; Gillardoni, Stefania; Zubieta Barragán, Ricardo; Martínez Castro, Daniel; Miranda-Corzo, Andrea; Bonasoni, Paolo; Silva Vidal, YaminaGlacial bodies in the Peruvian Andes Mountains store and supply freshwater to hundreds of thousands of people in central Peru. Atmospheric black carbon (BC) is known to accelerate melting of snow and ice, in addition to contributing to air pollution and the health of people. Currently there is limited understanding on the sources and temporal variability of BC in valley and mountain environments in Peru. To address this problem, this study combined surface observations of BC collected during 2022–2023 with WRF model simulations and HYSPLIT trajectories to analyze the dispersion and sources of BC in valley and high elevation environments and the associated local atmospheric circulations. Results show high BC concentrations are associated with the valley-mountain wind system that occurs on both sides of the Huaytapallana mountain range. A pronounced circulation occurs on the western slopes of Huaytapallana when concentrations of BC increase during daylight hours, which transports atmospheric pollutants from cities in the Mantaro River Valley to the Huaytapallana mountain range. Low concentrations of BC are associated with circulations from the east that are channeled by the pronounced ravines of the Andes-Amazon transition. On average, during the season of highest BC concentrations (July–November), the relative contributions of fossil fuels are dominant to biomass burning at the valley observatory and are slightly lower at the Huaytapallana observatory. These results demonstrate the need to promote mitigation actions to reduce emissions of BC and air pollution associated with forest fires and local anthropogenic activity.Item Open Access Emergent constraint on oxygenation of the upper South Eastern Pacific oxygen minimum zone in the twenty-first century(Nature Research, 2024-05-28) Almendra, Ivan; Dewitte, Boris; Garçon, Véronique; Muñoz, Praxedes; Parada, Carolina; Montes Torres, Ivonne; Duteil, Olaf; Paulmier, Aurélien; Pizarro, Oscar; Ramos, Marcel; Koeve, Wolfgang; Oschlies, AndreasAs a consequence of on-going global warming, the ocean is losing oxygen, which has implications not only in terms of marine resources management and food supply but also in terms of the potentially important feedback on the global carbon cycle and climate. Of particular scrutiny are the extended zones of already low levels of oxygen called the oxygen minimum zones (OMZs) embedded in the subsurface waters of the productive Eastern Boundary Upwelling Systems (EBUS). These OMZs are currently diversely simulated by state-of-the-art Earth System Models (ESM) hampering a reliable projection of ocean deoxygenation on marine ecosystem services in these regions. Here we focus on the most emblematic EBUS OMZs of the planet, that of the South Eastern Pacific (SEP), which is under the direct influence of the El Niño Southern Oscillation (ENSO), the main climate mode on interannual timescales at global scale. We show that, despite the low consensus among ESM long-term projections of oxygen levels, the sensitivity of the depth of the upper margin (oxycline) of the SEP OMZ to El Niño events in an ensemble of ESMs can be used as a predictor of its long-term trend, which establishes an emergent constraint for the SEP OMZ. Because the oxycline along the coast of Peru and Chile deepens during El Niño events, the upper bound of the SEP OMZ is thus likely to deepen in the future climate, therefore oxygenating the SEP OMZ. This has implications not only for understanding the nitrogen and carbon cycles at global scale but also for designing adaptation strategies for regional upper-ocean ecosystem services.Item Open Access Hailstorm events in the Central Andes of Peru: insights from historical data and radar microphysics(European Geosciences Union, 2024-04-18) Valdivia Prado, Jairo Michael; Flores-Rojas, José Luis; Prado, Josep J.; Guizado, David; Villalobos-Puma, Elver; Callañaupa, Stephany; Silva Vidal, YaminaHailstorms, while fascinating from a meteorological perspective, pose significant risks to communities, agriculture, and infrastructure. In regions such as the Central Andes of Peru, the characteristics and frequency of these extreme weather events remain largely uncharted. This study fills this gap by investigating the historical frequency and vertical structure of hailstorms in this region. We analyzed historical hailstorm records dating back to 1958 alongside 4 years of observations (2017–2021) from the Parsivel2 disdrometer and a cloud-profiling radar MIRA35c. Our findings indicate a trend of decreasing hail frequency (−0.5 events per decade). However, the p value of 0.07 suggests the need for further investigation, particularly in relation to environmental changes and reporting methods. The results show that hailstorms predominantly occur during the austral summer months, with peak frequency in December, and are most common during the afternoon and early evening hours. The analysis of radar variables such as reflectivity, radial velocity, spectral width, and linear depolarization ratio (LDR) reveals distinct vertical profiles for hail events. Two case studies highlight the diversity in the radar measurements of hailstorms, underscoring the complexity of accurate hail detection. This study suggests the need for refining the Parsivel2 algorithm and further understanding its classification of hydrometeors. Additionally, the limitations of conventional radar variables for hail detection are discussed, recommending the use of LDR and Doppler spectrum analysis for future research. Our findings lay the groundwork for the development of more efficient hail detection algorithms and improved understanding of hailstorms in the Central Andes of Peru.Item Open Access Evaluación de la respuesta hidrológica a cambios de precipitación y temperatura en el altiplano peruano(Instituto Mexicano de Tecnología del Agua, 2024-01-01) Laqui, Wilber; Zubieta Barragán, Ricardo; Laqui-Vilca, Yony; Alfaro, Roberto; Laqui-Vilca, César; Aragón, LuisLas cuencas de montaña son consideradas como los sistemas hidrológicos de mayor afectación por el cambio climático, estimándose impactos significativos en los recursos hídricos y las demandas de agua. Este estudio evalúa la respuesta hidrológica de una cuenca del altiplano peruano frente a cambios de los patrones de precipitación y temperatura. El conocer con anticipación el efecto del cambio climático sobre la oferta hídrica toma relevante importancia para la toma de decisiones en la planificación a corto, mediano y largo plazos del uso del agua y la gestión de los recursos hídricos. A partir de la implementación del Modelo Integrado de Cambio Climático y Recursos Hídricos (HydroBID) se evaluaron 30 escenarios climáticos que consideraron cambios en la precipitación entre -20 y +20 %, temperatura entre 0 y 6 °C, y combinaciones de éstos formulados según las proyecciones para el área de estudio disponibles en la literatura. Los resultados mostraron que por cada 10 % de incremento de la precipitación se produjo un aumento promedio de 23.4 % en el caudal; mientras que por cada 10 % de disminución de la precipitación se generó una reducción promedio del caudal de 16 %. Asimismo, se evidenció que por cada 1 °C de subida de la temperatura se generó en promedio un 5 % de reducción del caudal. Se determinó que la variación de las tasas de precipitación, temperatura y su interacción entre ellas generarían cambios en los caudales futuros, mostrando efectos en la variación temporal y espacial de la cuenca.Item Open Access Performance of Regional Climate Model Precipitation Simulations Over the Terrain-Complex Andes-Amazon Transition Region(American Geophysical Union, 2024-01-06) Gutierrez, Ricardo A.; Junquas, Clémentine; Armijos Cardenas, Elisa Natalia; Sörensson, Anna A.; Espinoza, Jhan-CarloRegional climate models (RCMs) are widely used to assess future impacts associated with climate change at regional and local scales. RCMs must represent relevant climate variables in the present-day climate to be considered fit-for-purpose for impact assessment. This condition is particularly difficult to meet over complex regions such as the Andes-Amazon transition region, where the Andean topography and abundance of tropical rainfall regimes remain a challenge for numerical climate models. In this study, we evaluate the ability of 30 regional climate simulations (6 RCMs driven by 10 global climate models) to reproduce historical (1981–2005) rainfall climatology and temporal variability over the Andes-Amazon transition region. We assess spatio-temporal features such as spatial distribution of rainfall, focusing on the orographic effects over the Andes-Amazon “rainfall hotspots” region, and seasonal and interannual precipitation variability. The Eta RCM exhibits the highest spatial correlation (up to 0.6) and accurately reproduces mean annual precipitation and orographic precipitation patterns across the region, while some other RCMs have good performances at specific locations. Most RCMs simulate a wet bias over the highlands, particularly at the eastern Andean summits, as evidenced by the 100%–2,500% overestimations of precipitation in these regions. Annual cycles are well represented by most RCMs, but peak seasons are exaggerated, especially at equatorial locations. No RCM is particularly skillful in reproducing the interannual variability patterns. Results highlight skills and weaknesses of the different regional climate simulations, and can assist in the selection of regional climate simulations for impact studies in the Andes-Amazon transition zone.