The datasets listed below are of prime importance to reach the goals of EECLAT. Through several projects, EECLAT is involved in either the production of these datasets, their exploitation for scientific purposes, or both.

The reasoning behind these projects is the creation of airborne, ground-based and satellite datasets that will help adapt existing algorithms to future spaceborne observations, and develop new ones taking advantage of technological advances in future observations (e.g. HSRL capabilities). As the instrumental design of the Earth-Care lidar and radar are different from the A-train counterparts, the level 1 dataset will be different for both missions. Differences between the signal produced by the EarthCare instruments and observations from the A-train must be studied and understood, in order to prepare future analyses of the EarthCare dataset.

Space data

Two main agile datasets based on spaceborne data are both produced and extensively used in the context of EECLAT.

• The DARDAR project aims at retrieving important cloud properties by combining colocated lidar and radar observations: CALIPSO and CloudSAT in the context of the A-Train (Delanoe and Hogan, 2010). This combination means DARDAR benefits from merging two instruments with different, but overlapping cloud sensitivities. Retrieved properties include cloud mask and rain, cloud phase and microphysics. Observations from the RALI platform (see airborne datasets above) are also used in the development of DARDAR. EECLAT includes work to adapt the DARDAR algorithms to the EarthCare ATLID/CPR combination (see Ceccaldi et al. 2013), and work on the production and cleanup of DARDAR products. The DARDAR product is available publicly through the ICARE thematic center.
• The GCM-Oriented CALIPSO Cloud Product (GOCCP) provides cloud detections based on CALIOP observations, from the profile level to global-scale monthly maps. Initially developed to evaluate the representation of clouds in models as part of the CFMIP-OBS initiative, its straightforward detection scheme compared to other CALIPSO cloud products led it to be used for scientific analysis of cloud cover as well. EECLAT supervises several aspects of GOCCP algorithm development, from its ongoing update cycle to its adaptation to future lidars such as EarthCare (CLIMP project). Several EECLAT projects use the GOCCP dataset for scientific purposes.  Animation M. Reverdy (LMD/ESA)

Airborne data

The RALI project consists of an airborne platform combining RASTA, a 95 GHz Doppler cloud radar and LNG, a 3-wavelength dual-polarization lidar (with High spectral resolution capability). RALI observations are used for the characterisation of the macrophysical, microphysical, radiative, and dynamical properties of clouds, aerosols, and convection. EECLAT includes work on taking and processing RALI observations during in-situ experimental campaigns, and several projects that benefit from RALI observations to build a prototype EarthCare dataset and develop retrieval algorithms suited for combined HSRL and Radar data.

Ground-based data are essential to capture the diurnal evolution of atmospheric properties, that eludes observations from sun-synchronous satellite instruments. Reconciling those ground-based datasets with spaceborne observations is necessary to extrapolate local findings to the global scale. Among the goals of EECLAT is to take advantage of, and help develop, multi-year/multi-decade ground-based continuous datasets. Through the involvement of key scientists and engineers, several observation facilities are important partners of EECLAT:

• The SIRTA Atmospheric Research Observatory provides multiple ground-based continous observations from key instruments (lidar, radar, radiometers, in-situ). The new high-power, multi-wavelength Raman Lidar IPRAL is scheduled to begin operation in early 2015 and will provide important data for EarthCare preparation. The BASTA Doppler Cloud Radar also operates in vertically-pointing mode at the SIRTA observatory.
• Observation facilities at OPGC/LaMP provides, among other measurements, vertical profiles of the atmosphere from a 355nm lidar with Raman capabilities: water vapor and N2 profiles are retrieved since 2009.
• OPAR provides, among other measurements, vertical profiles of the atmosphere from several lidars: tropospheric and stratospheric ozone, water vapor and N2 profiles.
• OHP provides, among other measurements (photometers, spectrometers, etc.), vertical profiles of stratospheric ozone, water vapor, temperature and aerosol concentration from a high-power lidar.

These facilities are all part of the national Réseau d’Observatoires pour la Surveillance de l’Eau Atmosphérique (ROSEA) observatory network and of the European Aerosols, Clouds and Trace Gases Research Infrastructure Network (ACTRIS). EECLAT includes several projects that take advantage of the continuous and long-term nature of these measurements to validate, develop and extend retrieval algorithms and scientific results.