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Impact of nitric acid on ice evaporation rates
Author(s) -
Warshawsky Matthew S.,
Zondlo Mark A.,
Tolbert Margaret A.
Publication year - 1999
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 - 10.1029/1999gl900120
Subject(s) - evaporation , nitric acid , relative humidity , torr , analytical chemistry (journal) , clear ice , supercooling , ice cloud , partial pressure , ice nucleus , materials science , atmospheric sciences , chemistry , cryosphere , sea ice , geology , meteorology , environmental chemistry , oxygen , thermodynamics , climatology , antarctic sea ice , inorganic chemistry , optics , radiative transfer , nucleation , physics , organic chemistry
Recent studies have suggested that nitric acid uptake by ice clouds may decrease ice evaporation rates and thereby prolong the cloud lifetimes. To test this suggestion, ice desorption rates were studied as a function of HNO 3 partial pressure (10 −6 –10 −5 Torr), relative humidity (28–92%), and temperature (192–204 K) using optical interference of a helium neon laser. Ice evaporation rates in the presence of 1 × 10 −6 Torr HNO 3 were indistinguishable from those of pure ice. In contrast, ice evaporation in the presence of 8 × 10 −6 Torr HNO 3 resulted in lower evaporation rates by 33% relative to pure ice. Higher partial pressures of HNO 3 result in a supercooled H 2 O/HNO 3 liquid layer over ice, which may freeze to form a sealed NAT coating. This causes a lowering of the ice evaporation rate and prolongs the lifetime of ice. Ice exposed to lower partial pressures of HNO 3 will not form a liquid layer and will thus evaporate at the same rate as pure ice.