Odin stratospheric proxy NO y measurements and climatology

• Main Authors: Brohede, S., Mclinden, C. A., Urban, Jakub, Haley, C. S., Jonsson, A. I., Murtagh, D.
• Other Authors: Department of Radio and Space Science Göteborg, Chalmers University of Technology Göteborg, Environment and Climate Change Canada, Centre for Research in Earth and Space Science Toronto (CRESS), York University Toronto, Department of Physics Toronto, University of Toronto
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Antarctic; The Antarctic; Antarc*
• Online Access: https://hal.science/hal-00304048; https://hal.science/hal-00304048/document; https://hal.science/hal-00304048/file/acpd-8-5847-2008.pdf

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.