Our goals

The EECLAT project aims to stimulate the French scientific community working with A-Train, ADM-Aeolus and Earth-CARE, with a special interest in active sensors. The EECLAT community develops and provides datasets and tools built around these concepts.

The annual EECLAT proposal aims at 1) gain support for the activities of several laboratories and groups working on atmospheric sciences through funding by CNES and INSU, and 2) provide a organised glimpse into the varied scientific interests of this community. We provide a space to foster community discussions on ongoing research projects and develop new ones.

Our scientific interests are mostly build around the study of clouds (including stratospheric ones) and aerosols.

The A-Train and EarthCare

The active sensors CALIOP (lidar) and CloudSAT (radar), in orbit as part of the A-Train between 2006 and 2018, have provided an unprecedented view of the atmosphere, documenting it along the vertical at a high spatial resolution (30m to 480m). The vertical dimension is a simple but key element to describe the stratified atmosphere, that was in the past only documented very indirectly and approximatively from space. It is, by itself, cutting edge information for atmospheric science studies.

As members of the A-Train until 2018, CALIPSO and CloudSat operated in concert with mature passive sensors such as CERESPARASOLMODIS that provide more information e.g. the radiative balance of the Earth, the amount and directionality of reflected light, and infrared emitted radiances. The A-train can document simultaneously the macrophysical, radiative, and to some extent microphysical properties of atmospheric particles (aerosols, clouds, polar stratospheric clouds). In synergy, A-train instruments can document atmospheric processes at regional and global scales.

Since 2018 CALIPSO and CloudSat have left the A-Train and now follow each other in a slightly lower orbit sometimes called the C-Train that slowly derives to the left. CloudSat is expected to resume scientific operations mid-2021, while CALIPSO is expected to  operate until late 2023.

The successful operation of these missions for over 14 years has led to large amounts of data, which permits to tackle seasonal and inter-annual variabilities key for climate studies. Strong of this success, the following ADM and Earth-Care missions take the next steps:

  1. To acquire 20+ years of active remote sensing observations from space by merging the A-train and ADM and Earth-Care data. This will let us document the decadal evolution of clouds, aerosols, and PSC.
  2. To improve lidar and radar observation capabilities based on the advanced design of ATLID (High Spectral Resolution Lidar) and CPR (Doppler radar) that will provide new information on atmospheric particles.

Efforts of the international community have led to an impressive amount of scientific discoveries based on the analysis of A-train data. A-Train design and scientific exploitation are supported by NASA and US scientists. The French scientific community of remote sensing experts participates in this effort through the involvement of CNES in CALIPSO and PARASOL. They devise advanced analysis techniques of core A-Train measurements (CALIPSO and CloudSat, but also MODIS, CERES and PARASOL). Their expertise on measurement technologies allows them to lead the research of several well-identified scientific issues. Through the experience gained by this involvement the French community is able to contribute significantly to the preparation of the european Earth-Care mission.


EECLAT is supported by CNES and CNRS/INSU.

Thanks to Zulip for providing a communication platform.

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