Browsing by Autor "Blacutt, Luis"

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Campaña de mediciones atmosféricas en Los Andes bolivianos realizada por equipo estudiantil boliviano-estadounidense
(Revista Boliviana de Física, 2023) Whiteman, David N.; Andrade, Marcos; Forno, Ricardo; Mamani-Paco, Rubén; Moreno, Isabel; Velarde, Fernando; Blacutt, Luis; Gutiérrez, Rene; Ávila, Fabricio; Pozadas, Mónica; Guzmán, Decker; Peltier, Richard; Acarapi, Adrián; Ajayi, Ayomiposi; Burgoa, Valeria; Callaú, Alan; Chambi, Yahuar Benjamín; García, Franco; Lobatón, Samantha; Oke, Hadijat; Okunuga, Fisayo; Peñaloza, Belén; Rivera, Marco Antonio; Watson, Monique; Reíd, Shayla; Zou, Hoven
Una campaña de campo para realizar mediciones atmosféricas, centrada en el trabajo de estudiantes tanto bolivianos como estadounidenses, se llevó a cabo el 24 de mayo de 2022. La campaña fue parte de un programa financiado por el Departamento de Estado de EE. UU, cuyo objetivo principal fue fomentar el intercambio cultural y científico entre estudiantes bolivianos y estadounidenses. Como parte de este intercambio, un grupo de ocho estudiantes bolivianos y cuatro estadounidenses trabajaron juntos para planificar y ejecutar mediciones enfocadas en cuantificar el flujo de material particulado desde la ciudad de La Paz hacia la cumbre del monte Chacaltaya, donde se encuentra la estación más alta del mundo de la red Global Atmosphere Watch. Las mediciones se realizaron en tres lugares a lo largo de un cañón que conduce hacia la cima del monte Chacaltaya y es una vía natural para que los contaminantes generados por la ciudad viajen hacia la estación. Las mediciones indicaron la presencia de un flujo de viento ascendente y descendente, generado por el calentamiento y enfriamiento producido por radiación solar o la falta de ésta, que ayuda al movimiento de aerosoles cerca de la superficie de la montaña. El desarrollo de procesos convectivos durante la tarde disminuyó regularmente las concentraciones medidas en la superficie y complicó así la interpretación de los flujos de partículas. Miembros del Laboratorio de Física Atmosférica (LFA) de la Universidad Mayor de San Andrés (UMSA) desarrollaron un novedoso sistema de sondas cautivas de bajo costo. El uso de estas sondas posibilitó adquirir perfiles verticales de vientos, temperatura, presión y humedad relativa, permitiendo así la investigación de la estructura vertical de la transición entre el flujo ascendente y descendente. Fuera de la campaña de medición, los estudiantes participaron juntos en actividades culturales para disfrutar atracciones locales y conocerse mejor. Uno de los objetivos del experimento era aumentar el interés por las ciencias atmosféricas entre los estudiantes de la UMSA. Los resultados de una encuesta posterior a la campaña indican que la participación en esta campaña de campo conjunta ha aumentado el número de estudiantes de física que participan en las actividades del LFA en la UMSA
Comment on ar-2024-15
(2024) Aliaga, Diego; Sinclair, Victoria A.; Krejci, Radovan; Andrade, Marcos; Artaxo, Paulo; Blacutt, Luis; Cai, Runlong; Carbone, Samara; Gramlich, Yvette; Heikkinen, Liine
Abstract. In this study, we investigate atmospheric new particle formation (NPF) across 65 days in the Bolivian Central Andes at two locations: the mountain-top Chacaltaya station (CHC, 5.2 km above sea level) and an urban site in El Alto-La Paz (EAC), 19 km apart and at 1.1 km lower altitude. We categorize days into four groups based on NPF intensity, determined with the daily maximum concentration of 4–7 nm particles: (A) high at both sites, (B) medium at both, (C) high at EAC but low at CHC, (D) and low at both. This categorization was premised on the assumption that similar NPF intensities imply similar atmospheric processes. Our findings show significant differences across the categories in terms of particle size and volume, precursor gases, aerosol compositions, pollution levels, meteorological conditions, and air mass origins. Specifically, intense NPF events (A) increased Aitken-mode particle concentrations (14–100 nm) significantly on 28 % of the days when air masses passed over the Altiplano. At CHC, larger Aitken-mode particle concentrations (40–100 nm) increased from 1.1×103 cm-3 (background) to 6.2×103 cm-3 very likely linked to the ongoing NPF process. High pollution levels from urban emissions on 24 % of the days (B) were found to interrupt particle growth at CHC and diminish nucleation at EAC. Meanwhile, on 14 % of the days, high concentrations of sulphate and large particle volumes (C) were observed, correlating with significant influences from air masses originating from the actively degassing Sabancaya Volcano and a depletion of positive 2–4 nm ions at CHC. During these days, reduced NPF intensity was observed at CHC but not at EAC. The study highlights the role of NPF in modifying atmospheric particles and underscores the varying impacts of urban versus mountain-top environments on particle formation processes in the Andean region.
Comment on ar-2024-15
(2024) Aliaga, Diego; Sinclair, Victoria A.; Krejci, Radovan; Andrade, Marcos; Artaxo, Paulo; Blacutt, Luis; Cai, Runlong; Carbone, Samara; Gramlich, Yvette; Heikkinen, Liine
Abstract. In this study, we investigate atmospheric new particle formation (NPF) across 65 days in the Bolivian Central Andes at two locations: the mountain-top Chacaltaya station (CHC, 5.2 km above sea level) and an urban site in El Alto-La Paz (EAC), 19 km apart and at 1.1 km lower altitude. We categorize days into four groups based on NPF intensity, determined with the daily maximum concentration of 4–7 nm particles: (A) high at both sites, (B) medium at both, (C) high at EAC but low at CHC, (D) and low at both. This categorization was premised on the assumption that similar NPF intensities imply similar atmospheric processes. Our findings show significant differences across the categories in terms of particle size and volume, precursor gases, aerosol compositions, pollution levels, meteorological conditions, and air mass origins. Specifically, intense NPF events (A) increased Aitken-mode particle concentrations (14–100 nm) significantly on 28 % of the days when air masses passed over the Altiplano. At CHC, larger Aitken-mode particle concentrations (40–100 nm) increased from 1.1×103 cm-3 (background) to 6.2×103 cm-3 very likely linked to the ongoing NPF process. High pollution levels from urban emissions on 24 % of the days (B) were found to interrupt particle growth at CHC and diminish nucleation at EAC. Meanwhile, on 14 % of the days, high concentrations of sulphate and large particle volumes (C) were observed, correlating with significant influences from air masses originating from the actively degassing Sabancaya Volcano and a depletion of positive 2–4 nm ions at CHC. During these days, reduced NPF intensity was observed at CHC but not at EAC. The study highlights the role of NPF in modifying atmospheric particles and underscores the varying impacts of urban versus mountain-top environments on particle formation processes in the Andean region.
Comment on egusphere-2023-526
(2023) Heitto, Arto; Wu, Cheng; Aliaga, Diego; Blacutt, Luis; Chen, Xuemeng; Gramlich, Yvette; Heikkinen, Liine; Huang, Wei; Krejci, Radovan; Laj, Paolo
Abstract. Early growth of atmospheric particles is essential for their survival and ability to participate in cloud formation. Many different atmospheric vapors contribute to the growth, but even the main contributors still remain poorly identified in many environments, such as high-altitude sites. Based on measured organic vapor and sulfuric acid concentrations under ambient conditions, particle growth during new particle formation events was simulated and compared with the measured particle size distribution at Chacaltaya Global Atmosphere Watch station in Bolivia (5240 m a.s.l.) during April and May 2018, as a part of the SALTENA (Southern Hemisphere high-ALTitude Experiment on particle Nucleation and growth) campaign . The simulations showed that the detected vapors were sufficient to explain the observed particle growth, although some discrepancies were found between modelled and measured particle growth rates. This study gives an insight on the key factors affecting the particle growth on the site. Low volatile organic compounds were found to be the main contributor to the particle growth, covering on average 65 % of simulated particle mass in particle with diameter of 40 nm In addition, sulfuric acid had a major contribution to the particle growth, covering at maximum 39 % of simulated particle mass in 40 nm particle during periods when volcanic activity was detected on the area, suggesting that volcanic emissions can greatly enhance the particle growth.
Comment on egusphere-2023-526
(2023) Heitto, Arto; Wu, Cheng; Aliaga, Diego; Blacutt, Luis; Chen, Xuemeng; Gramlich, Yvette; Heikkinen, Liine; Huang, Wei; Krejci, Radovan; Laj, Paolo
Abstract. Early growth of atmospheric particles is essential for their survival and ability to participate in cloud formation. Many different atmospheric vapors contribute to the growth, but even the main contributors still remain poorly identified in many environments, such as high-altitude sites. Based on measured organic vapor and sulfuric acid concentrations under ambient conditions, particle growth during new particle formation events was simulated and compared with the measured particle size distribution at Chacaltaya Global Atmosphere Watch station in Bolivia (5240 m a.s.l.) during April and May 2018, as a part of the SALTENA (Southern Hemisphere high-ALTitude Experiment on particle Nucleation and growth) campaign . The simulations showed that the detected vapors were sufficient to explain the observed particle growth, although some discrepancies were found between modelled and measured particle growth rates. This study gives an insight on the key factors affecting the particle growth on the site. Low volatile organic compounds were found to be the main contributor to the particle growth, covering on average 65 % of simulated particle mass in particle with diameter of 40 nm In addition, sulfuric acid had a major contribution to the particle growth, covering at maximum 39 % of simulated particle mass in 40 nm particle during periods when volcanic activity was detected on the area, suggesting that volcanic emissions can greatly enhance the particle growth.