The cornerstone of climate science is generation of climate data records (CDRs) that provide the observed record of climate and its past changes. CDRs are the basis for assessing our current understanding and the attribution of past changes in climate (e.g. the activity of IPCC and UNFCC), and are used, in part, to validate the models used for climate prediction. The most essential characteristic of a CDR is the stability of its uncertainty characteristics over time. While grounded in observations, CDRs are thus much more than the raw observations: rather, they are a synthesis of related observations, often from multiple instruments, taking account of anything that disturbs the homogeneity of the time series: e.g. variations in spatial coverage, orbital drifts, instrument degradation, and inconsistencies between the calibration of different versions of the same instrument.

The proposed project aims to improve the characterization of CDRs, and produce new CDRs, for four essential climate variables in the stratosphere (approximately 10-50 km altitude). Where possible the domain of study will extend into the lower mesosphere (to approximately 65 km altitude). In the stratosphere, space-based measurements are the dominant source of CDRs because of the limited extent of in-situ measurements compared with the troposphere, and the near-global coverage of space-based measurements. As a result of their pioneering developments in the early phase of the space age, the space-based stratospheric CDRs to date are reliant primarily on US (NOAA or NASA) data. The purpose of this study is to work towards the inclusion of ESA and ESA-TPM data in the stratospheric CDRs used by the stratospheric research community. This is a pressing need because a number of key US-based CDRs ended in 2005/2006: namely the SAGE-based ozone record, the SAGE-based aerosol record, the SSU-based temperature record, and the HALOE-based water vapour record. Since the ESA and ESA-TPM vertical profile observation records begin a few years before 2005/2006 and continue to the present, there is a period of overlap which allows for a potential extension in time of the existing CDRs.