ESA / ECSAT CCIWV.REP.022 Water Vapour Climate Change Initiative (WV_cci) - CCI+ Phase 2 D2.2 Figure 3-4: Same as Figure 3-3 but for bias-correction on MLS observation with reference to ACE-FTS profiles. 3.3 CDR-4 merging algorithm The merged monthly mean dataset of VRWV profiles is created from several satellite instruments: limb VRWV data from Aura-MLS and MIPAS and nadir VRWV data from RAL IMS. The monthly mean data from individual instruments, which are described in Section 3.2, are here used to calculate the merged monthly mean VRWV CDR-4.
Due to the limited spatial coverage of BBH observations, the merged product consists of a combination of original VRWV and bias-corrected VRWV profiles at different pressure levels following the merging rules given below: at and above 100 hPa (lower stratosphere), only original VRWV monthly mean data from MLS and MIPAS before bias-correction are used to calculate the average; 19