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Latitudinal dependence of noctilucent cloud growth
Author(s) -
Karlsson B.,
Rapp M.
Publication year - 2006
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 - 10.1029/2006gl025805
Subject(s) - atmospheric sciences , latitude , zonal and meridional , water vapor , environmental science , particle (ecology) , supersaturation , physics , meteorology , geology , astronomy , oceanography , thermodynamics
The latitudinal variation of NLC particle sizes is studied using scattered solar radiation spectra from the OSIRIS instrument onboard the Odin satellite obtained during the austral summer period 1 January–17 February 2005. We show that the particles grow moderately larger when approaching the pole, with effective optical radii of 65 nm/76 nm at latitudes of 70°/90° S. Microphysical modeling suggests that particles grow larger as a consequence of a combined effect of the temperature decrease toward the pole, the available water vapor, and meridional transport times. Interestingly, at latitudes closest to the pole, NLC particle sizes show a bi‐modal structure. This structure is suggested to arise from repeated growth cycles due to extended residence times in supersaturated air.