Open AccessApparent freezing temperatures modeled for several experimental apparatus
Author(s) -
Hung HuiMing,
Martin Scot T.
Publication year - 2001
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000jd000212
Subject(s) - nucleation , cirrus , ice nucleus , thermodynamics , homogeneous , cloud physics , polar , mass transfer , function (biology) , aqueous solution , materials science , physics , chemistry , atmospheric sciences , cloud computing , astronomy , evolutionary biology , biology , computer science , operating system
Ice formation by homogeneous nucleation in aqueous atmospheric particles composed of high ionic strength electrolytes is at times believed to be the dominant initiation step in cirrus and polar stratospheric cloud formation. Microphysical models of ice nucleation occurring during atmospheric processes are based upon volume nucleation rates, J ( T , x ), measured in laboratory experiments where T is temperature and x is mole fraction salt composition. At the present time, there are large discrepancies among apparent freezing temperatures reported by several investigators employing different experimental apparatus. One current hypothesis is that a common J function is expressed differently in these several techniques, which have variations in observation times, system volumes, vapor mass transfer, and so on. In the current paper, we model the several experiments based on a common J function and simulate apparent freezing temperatures of H 2 SO 4 /H 2 O and (NH 4 ) 2 SO 4 /H 2 O particles. We find that the experimental results can be categorized into two groups, one of which is consistent with a function J 1 and the other with J 2 , while J 1 and J 2 are mutually exclusive. We thus conclude no single J function exists that can simultaneously simulate all reported experimental results, thus refuting the previously proposed “common J ” hypothesis for the reconciliation of experimental results.