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- Title
Oxalic acid as a heterogeneous ice nucleus in the upper troposphere and its indirect aerosol effect.
- Authors
Zobrist, B.; Marcolli, C.; Koop, T.; Luo, B. P.; Murphy, D. M.; Lohmann, U.; Zardini, A.; Krieger, U. K.; Corti, T.; Cziczo, D. J.; Fueglistaler, S.; Hudson, P. K.; Thomson, D. S.; Peter, T.
- Abstract
Heterogeneous ice freezing points of aqueous solutions containing various immersed solid dicarboxylic acids (oxalic, adipic, succinic, phthalic and fumaric) have been measured with a differential scanning calorimeter. The results show that only the dihydrate of oxalic acid (OAD) acts as a heterogeneous ice nucleus, with an increase in freezing temperature between 2-5 K depending on solution composition. In several field campaigns, oxalic acid enriched particles have been detected in the upper troposphere with single particle aerosol mass spectrometry. Simulations with a microphysical box model indicate that the presence of OAD may reduce the ice particle number density in cirrus clouds by up to ∼50% when compared to exclusively homogeneous cirrus formation without OAD. Using the ECHAM4 climate model we estimate the global net radiative effect caused by this heterogeneous freezing to result in a cooling as high as -0.3Wm-2.
- Subjects
FREEZING points; CALORIMETERS; OXALIC acid; ICE nuclei; ATMOSPHERIC nucleation
- Publication
Atmospheric Chemistry & Physics Discussions, 2006, Vol 6, Issue 3, p3571
- ISSN
1680-7367
- Publication type
Article
- DOI
10.5194/acpd-6-3571-2006