Global ozone balance in the natural stratosphere

Abstract

The method of instantaneous rates is a three‐dimensional model that takes the observed distribution of atmospheric species and temperature as input data. The distribution of radiation over wavelength, photochemical rate constants, and reaction rates are evaluated in each cell of the three‐dimensional grid. For certain problems of restricted scope, definite answers can be given by this approach. For example, it is shown that the Chapman reactions and air motions are insufficient to give a global ozone balance; these factors account for only about 20% of the ozone produced below 45 km. There must be other photochemical or chemical reactions that destroy natural stratospheric ozone. The water reactions (H, HO, and HOO radicals) balance about 10% of the ozone produced below 45 km. Recently observed concentrations of nitrogen dioxide at up to 36‐km elevations are close to those required to destroy the remaining 70% of naturally produced ozone. Until enough measurements are made to characterize the vertical, latitudinal, and seasonal distribution of nitrogen dioxide, it will not be known whether yet other substances (such as chlorine, bromine, and metallic oxide particles) play a significant (10% or more) role in the natural ozone balance.

Evidence for a continuous decline in lower stratospheric ozone offsetting ozone layer recovery

“…Second, a rise in the tropopause (Santer et al, 2003), due to the warming troposphere, could lead to a decrease in ozone at mid-latitudes (Steinbrecht et al, 1998;Varotsos et al, 2004), but the tropopause rise is also affected by the ozone loss itself (Son et al, 2009), rendering its attribution difficult. Third, here we hypothesise a so-far-notdiscussed mechanism: an acceleration of the lower stratosphere BDC shallow branch (Randel and Wu, 2007;Oman et al, 2010) might increase transport of ozone-poor air to the mid-latitudes from the tropical lower stratosphere (Johnston, 1975;Perliski et al, 1989). The quality of the applied dynamical fields in the specified dynamics models considered in this study, or the way models handle transport in the lower stratosphere (SPARC, 2010;Dietmüller et al, 2017), may be dynamically related reasons why models do not reproduce the observed lower stratospheric ozone changes.…”

Monthly averages of nitrous oxide and ozone for the Northern and Southern Hemisphere high latitudes: A “1‐year climatology” derived from ILAS/ILAS‐II observations

“…In the Southern Hemisphere from January to March (Figures 5a–5c) summer ozone loss [e.g., Johnston , 1975; Farman , 1985] is noticeable by a general decline of ozone at altitudes above 20 km (550 K). In the ILAS/ILAS‐II data a negative correlation is found at all altitude levels (Figures 5a–5c) from January to March.…”

Ozone temperature correlations in the upper stratosphere as a measure of chlorine content

“…Our analysis of the chemical loss terms for ozone uses the concept of rate‐determining steps as described in Johnston [1975]. As an example the loss rate in molecules/cm 3 /sec for pure oxygen reactions is where k O,O3 (T) is the temperature‐dependent reaction rate coefficient for the reaction of O atoms with O 3 molecules given by k O,O3 (T) = 8.0 × 10 −12 e (−2060/T) cm 3 /molecule/sec [ Sander et al , 2011], [O] is the number density of oxygen atoms, and [O 3 ] is the number density of ozone molecules.…”