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Diurnal variation of nitric oxide at 26 km
Author(s) -
Kondo Y.,
Iwata A.,
Pirre M.,
Ramaroson R.,
Delannoy C.,
Matthews W. A.,
Koike M.,
Suzuki K.
Publication year - 1989
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/gl016i008p00867
Subject(s) - sunset , sunrise , descent (aeronautics) , atmospheric sciences , diurnal temperature variation , solar zenith angle , environmental science , altitude (triangle) , ozone , meteorology , variation (astronomy) , ozone depletion , zenith , stratosphere , physics , optics , astrophysics , geometry , mathematics
A chemiluminescent NO detector was launched from Uchinoura, Japan (31°N), at 0030 JST on July 29, 1987. The balloon reached a float altitude of 26 km at around 0200 JST and stayed at this altitude until 1600 JST when it started a slow descent. Near local sunrise, when the solar zenith angle reached 92.7°, the NO concentration started to increase rapidly. This rapid increase continued for about 30 minutes. The NO concentration continued to increase, albeit more slowly, for a further 7 to 8 hours, and then became stable. The NO diurnal variation is calculated by a time‐dependent photochemical model assuming a 14 ppbv total odd nitrogen concentration, constrained by ozone and temperature measured simultaneously with NO; the result agrees quite well with the observed temporal NO variation. The observed slow increase in NO can quantitatively be explained by the photodissociation of N 2 O 5 . The N 2 O 5 concentration just before sunset is estimated to be 1.9±0.4 ppbv at 26 km.