Figure 8: Composite maps of water vapor column-integrated
abundance and partitioning index. For the partitioning index, values
higher than 0.5 (in green) indicate that more than 50% of the water
vapor column is confined below 5 km, while lower values (in brown)
indicate that water vapor is more evenly dispersed with altitude. The
data has been averaged in bins of 2° latitude, 2° Ls and 4° longitude.
4.4 Deviances from the MCD
The synergistically retrieved column abundances and vertical confinement
shown in Figure 8 contain significant differences from the MCD prior
estimates. Figure 9 illustrates the deviance of the synergy from the MCD
estimates as a relative difference with the MCD abundances as reference
values (\(rel.diff.\ =\ \frac{SYN-MCD}{\text{MCD}}\)) , such that a
deviance of 0 means the synergy and the MCD are equal, and instances
where the synergy gives the larger values are positive. The relationship
between the retrieved and prior CIA is shown in the left column, and of
the retrieved and prior PI in the right column.
Figure 9 shows that, on the whole, the synergy has a tendency to
retrieve column abundances lower than the corresponding MCD prior
values. The sublimation peak in early summer (around Ls=110°), which
controls most of the total atmospheric water vapor throughout the year
on the whole planet, is significantly smaller than the MCD estimate, yet
agrees somewhat better with the MCD than the surrounding observations.
The total water content in the tropical fall is a good indicator of
meridional transport of vapor from northern polar regions
(Navarro et al.,
2014), and this is where the model and synergy are most similar.