Supplemental Information :High frequency new particle formation in the Himalayas

Rising air pollution levels in South Asia will have worldwide environmental consequences. Transport of pollutants from the densely populated regions of India, Pakistan, China, and Nepal to the Himalayas may lead to substantial radiative forcing in South Asia with potential effects on the monsoon circulation and, hence, on regional climate and hydrological cycles, as well as to dramatic impacts on glacier retreat. An improved description of particulate sources is needed to constrain the simulation of future regional climate changes. Here, the first evidence of very frequent new particle formation events occurring up to high altitudes is presented. A 16-month record of aerosol size distribution from the Nepal Climate Observatory at Pyramid (Nepal, 5,079 m above sea level), the highest atmospheric research station, is shown. Aerosol concentrations are driven by intense ultrafine particle events occurring on >35% of the days at the interface between clean tropospheric air and the more polluted air rising from the valleys. During a pilot study, we observed a significant increase of ion cluster concentrations with the onset of new particle formation events. The ion clusters rapidly grew to a 10-nm size within a few hours, confirming, thus, that in situ nucleation takes place up to high altitudes. The initiation of the new particle events coincides with the shift from free tropospheric downslope winds to thermal upslope winds from the valley in the morning hours. The new particle formation events represent a very significant additional source of particles possibly injected into the free troposphere by thermal winds.

Citation proposal
Hervé Venzac (Blaise Pascal University,CNRS) - Karine Sellegri (Blaise Pascal University;CNRS) - Paolo Laj (CNRS Laboratory of Meteorology Physics - Laboratory of Glaciology) - Paolo Villani (Blaise Pascal University) - Paolo Bonasoni (Institute of Atmospheric Sciences and Climate (ISAC) - CNR) - Angela Marinoni (Institute of Atmospheric Sciences and Climate (ISAC) - CNR) - Paolo Cristofanelli (Institute of Atmospheric Sciences and Climate (ISAC) - CNR) - Francescopiero Calzolari (Institute of Atmospheric Sciences and Climate (ISAC) - CNR) - Sandro Fuzzi (Institute of Atmospheric Sciences and Climate (ISAC) - CNR) - Stefano Decesari (Institute of Atmospheric Sciences and Climate (ISAC) - CNR) - Maria Cristina Facchini (Institute of Atmospheric Sciences and Climate (ISAC) - CNR) - Elisa Vuillermoz (Ev-K2-CNR) - Gian Pietro Verza (Ev-K2-CNR) (2008) . Supplemental Information :High frequency new particle formation in the Himalayas. https://geoportal.mountaingenius.org/geonetwork/srv/api/records/e08dff1f-df2b-4a64-9046-889edbbc0fd1

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Date ( Publication ): 2008-10-14T00:00:00

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Presentation form: Hardcopy document

Presentation form: Digital document

Other citation details: Proceedings of the National Academy of Sciences of the United States of America volume 105 n.41 Page 15666 –15671

Collective title: High frequency new particle formation in the Himalayas

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Purpose: The Proceedings of the National Academy of Sciences USA (PNAS) publishes research reports, commentaries, perspectives, and colloquium papers. In accordance with the guiding principles established by George Ellery Hale in 1914, PNAS publishes brief first announcements of Academy members' and foreign associates' (hereafter referred to as members) more important contributions to research and of work that appears to a member to be of particular importance. PNAS is a general science journal and all papers should be intelligible to a broad scientific audience.

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Blaise Pascal University,CNRS - Hervé Venzac ( )

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Blaise Pascal University;CNRS - Karine Sellegri ( )

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CNRS Laboratory of Meteorology Physics - Laboratory of Glaciology - Paolo Laj ( )

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Blaise Pascal University - Paolo Villani ( )

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Website: www.univ-bpclermont.fr