From ERA5 to ERA6

At ECMWF, reanalysis forms a key contribution to the Copernicus Services (C3S, CAMS) that are implemented  by  ECMWF on behalf of the European Commission. The most recent ECMWF global atmospheric reanalysis, ERA5, provides hourly snapshots of the Earth's atmosphere, land surface and ocean waves from 1940 with daily updates 5 days behind real time. It has hundreds of thousands of users in many sectors in society, ranging from scientific to commercial applications. ERA5 has become a major training dataset for data-driven weather prediction models.

The production of its successor, ERA6, is underway. It benefits from eight additional years of R&D at ECMWF, more and better observations and forcing datasets, and 14km (rather than 31km) horizontal resolution for the atmosphere, land and ocean waves. The model component includes a coupled ocean (at 0.25 degree horizontal resolution), using initial ocean conditions from the ORAS6 ocean reanalysis. ERA6 resolves several ERA5 known issues. This includes taking better care of systematic model errors in the stratosphere, to further improve the quality of climate trends in this domain.

Based on user demand, ERA6 will contain a number of new products. These include 3D ocean fields plus a number of 2D key variables, 3D Clear-Air Turbulence, several new atmospheric surface parameters and a number of key parameters on height levels up to 500 metres from the surface. All fields vary hourly, and in addition to monthly, daily precalculated statistics will be provided as well.

Like ERA5, ERA6 is produced in parallel streams of 10 years each. Such streams from 1987 are produced and made available first, while streams back to around 1950 will be produced later.

This presentation will provide a summary of ERA5, what is new in ERA6 with respect to science and products, will show some initial ERA6 results and will indicate projected timelines.