Research Data supporting "Background free-tropospheric ice nucleating particle concentrations at mixed-phase cloud conditions"
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Clouds containing ice are vital for precipitation formation and play a critical roleare important in determining the Earth’s radiative budget. However, primary formation of ice in clouds is not fully understood. In the presence of ice nucleating particles (INPs), the phase change from water or vapor to ice is promoted, but identification and quantification of INPs in a natural environment remains challenging because of their low numbers. In this workpaper, we quantify the INP number concentrations in the free troposphere (FT) as measured at the High Altitude Research Station Jungfraujoch (JFJ), in the years 2014 – 2017during the in winter, spring and summer of the years 2014 - 2017. INPs are were measured at conditions relevant for mixed-phase cloud formation at T = 241/242 K. To date, these this measurements provideis the longest timeline of semi-regular measurements akin to online INP monitoring at this site and sampling conditions. During the different years and seasons, we We find that INP concentrations in the background FT are on average capped at 10 stdL-1 (liter of air at standard conditions (T = 273 K and p = 1013 hPa)) with an inter-quartile range of 0.4 – 9.6 stdL-1, as compared to measurements during times when other air mass origins (e.g. Sahara or marine boundary layer) prevailed. Elevated concentrations were measured in the field campaigns of 2016, which might be due to enhanced influence from Saharan dust and marine boundary layer air arriving at the JFJ. The upper limit of INP concentrations in the background FT is supported by measurements performed at similar conditions, but at different locations in the FT, such as ground- and airborne measurements over the central and Western United States and the Canary Islands, where we find the majority of INP concentrations to be below 13 stdL-1 most of the time. Mehr anzeigen
BeteiligteKontaktperson: Kanji, Zamin A
Kontaktperson: Lacher, Larissa
Datensammler(in): Lacher, Larissa
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Is supplement to: https://doi.org/10.1029/2018JD028338