The SALTENA Experiment: Comprehensive Observations of Aerosol Sources, Formation, and Processes in the South American Andes

Federico Bianchi , Victoria A. Sinclair , Diego Aliaga , Qiaozhi Zha , Wiebke Scholz , Cheng Wu , Liine Heikkinen , Rob Modini , Eva Partoll , Fernando Velarde , Isabel Moreno , Yvette Gramlich , Wei Huang , Alkuin Maximilian Koenig , Markus Leiminger , Joonas Enroth , Otso Peräkylä , Angela Marinoni , Chen Xuemeng , Luis Blacutt , Ricardo Forno , Rene Gutierrez , Patrick Ginot (1) , Gaëlle Uzu (1) , Maria Cristina Facchini , Stefania Gilardoni , Martin Gysel-Beer , Runlong Cai , Tuukka Petäjä , Matteo Rinaldi , Harald Saathoff , Karine Sellegri (2) , Douglas Worsnop , Paulo Artaxo , Armin Hansel , Markku Kulmala , Alfred Wiedensohler , Paolo Laj (1) , Radovan Krejci , Samara Carbone , Marcos Andrade , Claudia Mohr

1 IGE - Institut des Géosciences de l’Environnement
2 LaMP - Laboratoire de Météorologie Physique

This paper presents an introduction to the Southern Hemisphere High Altitude Experiment on Particle Nucleation and Growth (SALTENA). This field campaign took place between December 2017 and June 2018 (wet to dry season) at Chacaltaya (CHC), a GAW (Global Atmosphere Watch) station located at 5,240 m MSL in the Bolivian Andes. Concurrent measurements were conducted at two additional sites in El Alto (4,000 m MSL) and La Paz (3,600 m MSL). The overall goal of the campaign was to identify the sources, understand the formation mechanisms and transport, and characterize the properties of aerosol at these stations. State-of-the-art instruments were brought to the station complementing the ongoing permanent GAW measurements, to allow a comprehensive description of the chemical species of anthropogenic and biogenic origin impacting the station and contributing to new particle formation. In this overview we first provide an assessment of the complex meteorology, airmass origin, and boundary layer-free troposphere interactions during the campaign using a 6-month high-resolution Weather Research and Forecasting (WRF) simulation coupled with Flexible Particle dispersion model (FLEXPART). We then show some of the research highlights from the campaign, including (i) chemical transformation processes of anthropogenic pollution while the air masses are transported to the CHC station from the metropolitan area of La Paz-El Alto, (ii) volcanic emissions as an important source of atmospheric sulfur compounds in the region, (iii) the characterization of the compounds involved in new particle formation, and (iv) the identification of long-range-transported compounds from the Pacific or the Amazon basin. We conclude the article with a presentation of future research foci. The SALTENA dataset highlights the importance of comprehensive observations in strategic high-altitude locations, especially the undersampled Southern Hemisphere.

Domains: Sciences of the Universe [physics]

Federico Bianchi, Victoria A. Sinclair, Diego Aliaga, Qiaozhi Zha, Wiebke Scholz, et al.. The SALTENA Experiment: Comprehensive Observations of Aerosol Sources, Formation, and Processes in the South American Andes. Bulletin of the American Meteorological Society, 2022, 103, pp.E212-E229. ⟨10.1175/BAMS-D-20-0187.1⟩. ⟨insu-03706397⟩