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Fig. 34.1 Effect of the multi-species assimilation (MSA) on modeled zonal mass weighted OH
additional O 3 corrections are contributed by chemical feedback of the optimized O 3
precursors.
According to Fig. 34.1, the multi-species assimilation (MSA) drastically reduces
the modeled OH concentration especially over the tropics as well as the northern midlatitudes in contrast to single instrument run. The magnitude of the OH changes using
MSA is larger than the aggregation of all OH changes brought by single instrument
runs, suggesting strong chemistry nonlinearity in the model. The resulting global
mean OH has been decreased from 13.89 to 12.38 (in 10
5 mol/cm
3 ), comparable
to the estimated values of 12.44 from Spivakovsky et al. [3]. This shows the potential that assimilating multi-species observations could constrain tropospheric OH
concentrations.
34.3.2 CO Emission Scaling Factor in Aug-2016
Figure 34.2 shows the difference of anthropogenic and biomass burning CO emisFig. 34.2 Differences in anthropogenic and biomass burning CO emissions compared to the a
priori run (left), for assimilating MOPITT only (middle) and for the multi-species assimilation
MSA (right)