The Cloud_cci project covers the cloud component in the European Space Agency’s (ESA) Climate Change Initiative (CCI) programme.

In Cloud_cci, long-term and coherent cloud property datasets have been generated for which the synergistic capabilities of different Earth observation missions (European and non-European) were exploited.

A centrepiece of this activity has been the development and application of two state-of-the-art physical retrieval systems that use the optimal estimation technique for a simultaneous, spectrally consistent retrieval of cloud properties including pixel-based uncertainty measures:

After producing prototype datasets (version 1), a series of multi-annual, global datasets were generated using the passive imager satellite sensors listed above. These datasets (version 2 hereafter) were comprehensively evaluated and documented. Updates of a subset of these datasets (version 3) benefited from retrieval improvements, were characterised by extended temporal coverage and included consistently derived radiation properties in addition to the cloud properties.

In the new project phase (Cloud_cci+) the focus is on the European sensors SEVIRI and SLSTR that provide higher spatial and/or temporal resolution than the previously used sensors. Additionally, the full spectral information of these sensors for the retrieval of cloud and radiation properties is being exploited.