Odin stratospheric proxy NO y measurements and climatology
International audience Five years of OSIRIS (Optical Spectrograph and InfraRed Imager System) NO 2 and SMR (Sub-Millimetre Radiometer) HNO 3 observations from the Odin satellite, combined with data from a photochemical box model, have been used to construct a stratospheric proxy NO y data set includ...
Main Authors: | , , , , , |
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Other Authors: | , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2008
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Subjects: | |
Online Access: | https://hal.science/hal-00304048 https://hal.science/hal-00304048/document https://hal.science/hal-00304048/file/acpd-8-5847-2008.pdf |
Summary: | International audience Five years of OSIRIS (Optical Spectrograph and InfraRed Imager System) NO 2 and SMR (Sub-Millimetre Radiometer) HNO 3 observations from the Odin satellite, combined with data from a photochemical box model, have been used to construct a stratospheric proxy NO y data set including the gases: NO, NO 2 , HNO 3 , 2×N 2 O 5 and CIONO 2 . This Odin NO y climatology is based on all daytime measurements and contains monthly mean and standard deviation, expressed as mixing ratio or number density, as function of latitude or equivalent latitude (5° bins) on 17 vertical layers (altitude, pressure or potential temperature) between 14 and 46 km. Comparisons with coincident NO y profiles from the Atmospheric Chemistry Experiment?Fourier Transform Spectrometer (ACE-FTS) instrument were used to evaluate several methods to combine Odin observations with model data. This comparison indicates that the most appropriate merging technique uses OSIRIS measurements of NO 2 , scaled with model NO/NO 2 ratios, to estimate NO. The sum of 2×N 2 O 5 and CIONO 2 is estimated from uncertainty-based weighted averages of scaled observations of SMR HNO 3 and OSIRIS NO 2 . Comparisons with ACE-FTS suggest the precision (random error) and accuracy (systematic error) of Odin NO y profiles are about 15% and 20%, respectively. Further comparisons between Odin and the Canadian Middle Atmosphere Model (CMAM) show agreement to within 20% and 2 ppb throughout most of the stratosphere except in the polar vortices. A particularly large disagreement within the Antarctic vortex in the upper stratosphere during spring indicates too strong descent of air in CMAM. The combination of good temporal and spatial coverage, a relatively long data record, and good accuracy and precision make this a valuable NO y product for various atmospheric studies and model assessments. |
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