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Formation and implications of ice particle nucleation in the stratosphere
Author(s) -
Tabazadeh Azadeh,
Toon Owen B.,
Jensen Eric J.
Publication year - 1997
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/97gl01883
Subject(s) - ice nucleus , nucleation , ice crystals , stratosphere , ice cloud , particle (ecology) , clear ice , sea ice growth processes , classical nucleation theory , condensation , crystallization , aqueous solution , frost (temperature) , materials science , thermodynamics , chemical physics , atmospheric sciences , chemistry , meteorology , geology , physics , arctic ice pack , optics , sea ice , antarctic sea ice , oceanography , radiative transfer
The classical nucleation theory of homogeneous freezing along with a thermodynamic model of aqueous HNO 3 is used to calculate the critical temperatures and compositions at which ice crystals will nucleate from an aqueous HNO 3 droplet. Assuming that stratospheric aerosols are composed of aqueous HNO 3 near the ice frost point, we show that ice particle formation in the stratosphere can only occur if the air mass is cooled to about 2 to 3 K below the equilibrium condensation point of ice. A simple function is given for predicting the nucleation temperature of ice particle formation in the stratosphere from the ambient water vapor concentration. Microphysical calculations show that only fast cooling rates (> 500 K day −1 ) encountered in cold lee waves are rapid enough for nucleating the majority of the background aerosols into ice particles. The likelihood that ice crystals formed in lee waves may result in the subsequent crystallization of HNO 3 in the droplets is discussed. The barrier to ice formation by heterogeneous gas phase nucleation is compared to that of homogeneous freezing nucleation.