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Phase transformations of the ternary system (NH 4 ) 2 SO 4 ‐H 2 SO 4 ‐H 2 O and the implications for cirrus cloud formation
Author(s) -
Martin Scot T.
Publication year - 1998
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 - 10.1029/98gl00634
Subject(s) - cirrus , nucleation , homogeneous , aerosol , troposphere , ion , kinetic energy , ternary operation , cloud physics , phase (matter) , thermodynamics , materials science , cloud computing , physics , atmospheric sciences , meteorology , quantum mechanics , computer science , programming language , operating system
Homogeneous and heterogeneous growth mechanisms for cirrus cloud formation are considered in light of recent measurements showing the presence of NH 4 + ions in the aerosol of the upper troposphere. Low‐temperature ternary phase diagrams of (NH 4 ) 2 SO 4 ‐H 2 SO 4 ‐H 2 O are presented, and the thermodynamic and the kinetic data of the phase transitions are employed to consider the implications of NH 4 + ions on the mechanisms of cirrus cloud formation. The analysis concludes that changes in the degree of ammoniation can lead to a crossover in the cloud growth system from homogeneous to heterogeneous nucleation. A corresponding change in the cloud's particle distribution alters the cloud's radiative properties, persistence, and surface area available for heterogeneous chemistry.