Figure 5: Overview of the relative statistical distributions of fulfilled criteria. The full synergy dataset is shown in the top panel, the synergetic retrievals in MY 27 in the second, SPICAM/NIR is shown in the third panel, while PFS/TIR is illustrated in the bottom panel. Retrievals with the individual instruments were only conducted for MY 27. The y-axis counts the number of fulfilled criteria, and the x-axis shows the number of retrievals per 10 000 which fulfill each criterium configuration, sorted with the most likely configuration to the left, and decreasingly likely configurations towards the right.
4 Results
The results presented below were derived using data from two time intervals; Ls=334 of MY 26 until the end of MY 29, and from the beginning of MY 32 to the end of MY 34. The spatial and temporal coverage within each year is highly variable. All four selection criteria described in section 3.2 were applied, with limits as shown in Figure 5 (except for the assembly of the column abundance climatology in section 4.1, which uses limits specifically adjusted for column abundances). The first part of this section focuses on the retrieval of total column abundances with the synergy compared to with single spectral domain approaches and to the MCD. Then, results concerning the vertical partitioning of water is shown, as seen in relation to the total column and model predictions, where special attention is given to the polar regions around the seasonal ice cap sublimation seasons.
4.1 Column abundance climatology
For the assembly of a complete and composite synergy climatology of water vapor, the criteria described in Section 3 are applied to the complete dataset shown in Figure 2, with an adjustment to the DOF and error ratio limits. The DOF and error ratio requirements ensure retrievals with sufficient vertical information to justify further analysis of partitioning, and as there is no need for vertical information content for a column abundance climatology, the DOF and error ration limits are both set to 1, which is more than sufficient to infer a highly reliable column abundance.
After the adjusted selection criteria are applied, the remaining water vapor retrievals are illustrated as a function of season, latitude and longitude in Figure 6. In order to account for topography, the total water columns are normalized to an equivalent surface pressure of 610 Pa using the MCD to constrain local pressure. However, this pressure normalization is made on the assumption that water vapor is well mixed with the ambient gases, which might not always be the case. The total water columns are averaged in bins of 2° Ls, 2° latitude and 4° longitude. Of all qualified retrievals, 31% are from MY 27, which for the most part contributes to the coverage of the northern summer.