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Investigating possible causes of the observed diurnal variability in Antarctic NO y
Author(s) -
Weller R.,
Minikin A.,
KönigLanglo G.,
Schrems O.,
Jones A. E.,
Wolff E. W.,
Anderson P. S.
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 - 10.1029/1999gl900608
Subject(s) - snow , diurnal cycle , environmental science , morning , atmospheric sciences , climatology , diurnal temperature variation , nitrate , geology , meteorology , geography , chemistry , physics , organic chemistry , astronomy
The occurence of a diurnal variability in measured total oxidised nitrogen (NO y ) was observed at Neumayer, Antarctica, (70°39′S, 8°15′W) during a recent summer measurement campaign. Minima and maxima occurred in the early morning/early evening respectively, with the amplitude of the cycle around 40% of the daily mean NO y values. Given that this campaign was the first to attempt NO y measurements on the Antarctic continent, it is not presently clear whether this is an Antarctic‐wide phenomenon, or local to Neumayer. A similar cycle was observed for HNO 3 , although HNO 3 concentrations and fluctuations are too small to account for all of the NO y variability. In this paper we investigate possible mechanisms that might cause such diurnal signals, focussing on the influence of local meteorology and also of the snow‐pack. Exchange processes at the air/snow interface appear to dominate the observed NO y variability, although an influence from the changing surface inversion strength exists. These findings have important implications in understanding and hence correctly interpreting ice core nitrate data.