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Can we define an asymptotic value for the ice active surface site density for heterogeneous ice nucleation?
Author(s) -
Niedermeier Dennis,
AugustinBauditz Stefanie,
Hartmann Susan,
Wex Heike,
Ignatius Karoliina,
Stratmann Frank
Publication year - 2015
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2014jd022814
Subject(s) - nucleation , ice nucleus , plateau (mathematics) , particle (ecology) , dispersity , particle size , fraction (chemistry) , mineralogy , materials science , thermodynamics , chemistry , geology , mathematics , physics , chromatography , mathematical analysis , polymer chemistry , oceanography
The immersion freezing behavior of droplets containing size‐segregated, monodisperse feldspar particles was investigated. For all particle sizes investigated, a leveling off of the frozen droplet fraction was observed reaching a plateau within the heterogeneous freezing temperature regime ( T >− 38°C). The frozen fraction in the plateau region was proportional to the particle surface area. Based on these findings, an asymptotic value for ice active surface site density n s , which we namedn s ⋆ , could be determined for the investigated feldspar sample. The comparison of these results with those of other studies not only elucidates the general feasibility of determining such an asymptotic value but also shows that the value ofn s ⋆strongly depends on the method of the particle surface area determination. However, such an asymptotic value might be an important input parameter for atmospheric modeling applications. At least it shows that care should be taken when n s is extrapolated to lower or higher temperature.