A test of odd‐oxygen photochemistry using Spacelab 3 Atmospheric Trace Molecule Spectroscopy observations

The ozone profile calculated using a one‐dimensional time‐dependent photochemical model, with recommended absorption cross sections and reaction rate constants, is systematically less than Spacelab 3 (May 1985) Atmospheric Trace Molecule Spectroscopy (ATMOS) observations at sunset (χ = 90°), 30°N latitude, throughout the upper stratosphere and mesosphere. Model results are ∼9% smaller than the nominal ATMOS O 3 value at 40 km and 50% less at 76 km. Given the uncertainties associated with the ATMOS profile, the model “deficit” may be as large as 15% at 36 km, increasing to ∼70% at 76 km. A similar model O 3 deficit exists at sunrise, 47°S latitude, in the stratosphere: nominal differences of ≤25%, increasing to ≤45% when the ATMOS uncertainties are considered. Model results closely approximate ATMOS observations in both the upper stratosphere and mesosphere upon enhancing odd‐oxygen production by increasing the O 2 Schumann‐Runge band and Herzberg continuum cross section values used in the calculations.