Creating long-term climate data records using transfer functions: methodology and application for SAGE II, MIPAS and OMPS ozone profile datasets

Merging data records from different instruments into a consistent long-term data record is challenging process, especially when the parent datasets have a very short overlap or do not overlap at all. In addition, parent datasets can have different vertical resolutions and temporal and spatial samplings. In these cases, there is a need for a transfer standard - an independent data record that overlaps with parent datasets, allowing to characterize differences between the parent datasets and to derive absolute adjustments. In this study we discuss requirements for the transfer standard including long-term stability, spatial and temporal sampling. We estimate how various properties of the transfer standard affect stability of the merged record and derived long-term trends. We merge SAGE II, MIPAS and OMPS LP ozone data using MLS, ACE-FTS or model data records as transfer standards and analyze differences in the merged records imposed by the transfer standards.