Uncertainty characterised Fundamental Climate Data Records for the use in renalyses

Climate change is currently one of the main threats our planet is facing. Observations are playing a pivotal role in underpinning the science to understand the climate system and monitor its changes including extreme events, which have adverse effects on human lives. Information generated from measurements by Earth observation satellites contribute significantly to the development of this understanding and to the continuous monitoring of ongoing climate change and its impacts. However, the meaningful use of data from these satellites requires them to be long-term, spatially and temporally homogeneous, and uncertainty characterised. The process of preparing satellite data for climate studies is tedious and only recently being recognised as fundamental first step in preparing records of Essential Climate Variables (ECV) from these data.

During the last decade EUMETSAT has generated several fundamental climate data records (FCDR) consisting of measurements from instruments operating from microwave to visible frequencies. These measurements are not only from EUMETSAT’s own satellite but also from satellites operated by other agencies such as NOAA and CMA. Scientific advances for the data generation have been made through several EU research projects such as ERA-CLIM, FIDUCEO and GAIA-CLIM. FIDUCEO project was pivotal for developing a framework for characterising uncertainties of Earth Observation data. The principles developed in the project have been adapted and or extended by EUMETSAT by including other sensors and by consolidating longer time series.

This presentation outlines the basic principles of FCDR generation illustrated through a few examples. Basic steps of the FCDR generation is comprised of quality control of the raw data, recalibration of the raw data to produce physical quantities, such as radiances or reflectance, generate quality indicators, and create the outputs in user-friendly formats, e.g., NetCDF4. Furthermore, uncertainty characterisation and harmonisation of a suit of instruments are performed. We illustrate these principles by two examples, one on the creation of harmonised time series of microwave humidity sounder data and the other on the creation of FCDRs from geostationary satellite infrared and visible measurements. 

These FCDRs are then used to create data records of ECVs for example by the EUMETSAT Satellite Application Facilities (SAFs). EUMETSAT data records support international research activities in the World Climate Research Programme (WCRP) and national and international climate services such as the Copernicus Climate Change Service. Illustration of the use of FCDRs to improve the quality of CDRs will be presented.