Revisiting ice nucleation from precipitation samples. Issue 20 (29th October 2015)

• Record Type: Journal Article
• Authors: Petters, M. D.; Wright, T. P.
• Is Part Of: Geophysical research letters. Volume 42:Issue 20(2015:Oct.)
• Page Start: 8758
• Page End: 8766
• Publication Date: 2015-10-29
• Subjects: heterogeneous ice nucleation -- mixed‐phase clouds -- precipitation -- aerosol‐cloud‐climate interaction -- biological ice nuclei; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2015GL065733
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: An emerging and unsolved question is the sensitivity of cloud processes, precipitation, and climate to the atmospheric ice nucleus spectrum. This work revisits estimation of atmospheric ice‐nucleating particle concentration derived from cloud water and precipitation samples representing a wide range of geographical locations, seasons, storm systems, precipitation types, instruments, concentrations, and temperatures. Concentrations of ice‐nucleating particles are shown to vary over 10 orders of magnitude. High variability is observed in the −5°C to −12°C range which is suggested to be biologically derived nuclei whose life cycle is associated with intermittent source and efficient sink processes. The highest ever observed nucleus concentrations at −8°C are 3 orders of magnitude lower than observed ice crystal concentrations in tropical cumuli at the same temperature. The observed upper and lower limits of the nucleus spectrum provide a possible constraint on minimum enhancement factors for secondary ice formation processes. Key Points: New measurements of ice‐nucleating particle in snow, sleet, and rainwater samples Nucleus concentration varies over 10 orders of magnitude between −5 and −38°C Ice nucleus spectrum shows high variability between −5 and −12°C