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HNO 3 partitioning in cirrus clouds
Author(s) -
Meilinger S. K.,
Tsias A.,
Dreiling V.,
Kuhn M.,
Feigl Ch.,
Ziereis H.,
Schlager H.,
Curtius J.,
Sierau B.,
Arnold F.,
Zöger M.,
Schiller C.,
Peter Th.
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 - 10.1029/1999gl900423
Subject(s) - cirrus , ice cloud , troposphere , nitric acid , atmospheric sciences , particle (ecology) , aerosol , tropopause , ice core , environmental science , chemistry , analytical chemistry (journal) , climatology , environmental chemistry , geology , satellite , physics , inorganic chemistry , oceanography , astronomy , organic chemistry
During the 1997 POLSTAR‐1 winter campaign in northern Sweden a flight was performed across a cold trough of air (≃ 196 K) in the tropopause region. Measurements of total water vapour, nitric acid, particles and reactive nitrogen (NO y ) were taken. The particle measurements indicate that about 3% of the particles in the moist tropospheric air were ice particles. Forward and backward facing NO y inlets were used simultaneously to determine condensed phase HNO 3 . The combined NO y and particle measurements reveal that less than 1% of a monolayer of NO y could have resided on the ice particles. This casts doubt on the hypothesis that sedimenting cirrus particles generally lead to a strong downward flux of NO y . In addition to the NO y measurements, independent HNO 3 measurements were used to determine total HNO 3 . Although quantitative uncertainties do not allow to completely rule out that the NO y uptake on ice was limited by total HNO 3 , the combined NO y and HNO 3 data suggest that there was low uptake of NO y on ice despite abundant HNO 3 in the gas phase. Model studies indicate, that the most likely explanation of the measured nitric acid partitioning is given by HNO 3 in ternary solution droplets coexisting with almost HNO 3 free ice in the same air mass.