Mission
Clouds are a crucial component of the climate system, determining atmospheric energy balance and dynamics through processes such as radiation fluxes and transport of energy, moisture and momentum. In particular, deep convective clouds in the tropics are crucial for the climate system. However, use of cloud data is still uncommon in numerical weather prediction (NWP) and climate prediction, contributing to the status of clouds as one of the major climate uncertainties (Zelinka et al. 2020). One reason is that clouds change are challenging to observe. In particular, several properties of clouds, such as cloud fraction, height distribution, particle size and shape and internal variability determine the clouds’ impact, while many observation methods can only determine a few of those parameters. Progress has been made in recent years in the use of satellite observations. The combination of CloudSat cloud radar data and CALIPSO lidar data has been instrumental in improving understanding of cloud processes through detailed information on cloud phase, hydrometeors and structure (e.g. Forbes & Ahlgrimm 2014).
Data from the EarthCARE satellite (Wehr et al. 2023) launched in 2024 will improve strongly on the possibilities of CloudSat / CALIPSO data, due to more precise observations and added capabilities such as a Doppler radar, improved retrieval algorithms and synergistic data products, additional high-level products such as radiative fluxes and the advantage of having multiple instruments co-located on the same platform. EarthCARE’s instruments are an atmospheric lidar (ATLID, developed by Airbus Defence and Space in Toulouse), a 94 GHz Doppler cloud profiling radar (CPR), a 7-channel multi-spectral imager (MSI) and a 3-view broadband radiometer (BBR). The combination of these instruments will allow high precision retrievals of aerosol and cloud ice, snow, water and rain (ACM-CAP product, Mason et al. 2023), while the combination of profiling and imager data allows reconstruction of 3D cloud scene structure (ACM-3D, Qu et al. 2022), and one- and three-dimensional radiative transfer calculations (ACM-RT, Cole et al. 2022) in addition to radiation budget observations from the BBR. The EarthCARE data products will become available progressively, with the last releases planned for autumn 2025.
For this project, we plan to use the unique new EarthCARE dataset to understand the structure of tropical convective clouds, their interaction with radiation their role for the Earth system’s energy budget. We will use the ACM-CAP and ACM-3D products to evaluate cloud hydrometers and 3D structure, and utilise radiative transfer models such as the ecRad scheme widely used in numerical atmospheric models (Hogan & Bozzo 2018) as well as EarthCARE’s own radiation products to determine the impact on radiation, and how this depends on cloud properties. This will allow us to reduce the large uncertainty in the role of clouds for energy fluxes in the Earth System. By considering how these processes are treated in climate models, such as the AROME-Climat and ARPEGE-Climat at Météo-France, we can gain further insights into the processes involved and feedbacks in the Earth system, and derive an additional benefit for model improvements and climate science. Combining EarthCARE’s new and improved data with new capabilities in radiative transfer models will allow us to take the most advantage of these current developments to advance understanding of tropical cloud processes in Earth’s climate.
Cole, J. N. S., Barker, H. W., Qu, Z., Villefranque, N., & Shephard, M. W. (2022). Broadband radiative quantities for the EarthCARE mission: the ACM-COM and ACM-RT products. Atmospheric Measurement Techniques Discussions, 2022, 1-37.
Forbes, R. M., & Ahlgrimm, M. (2014). On the representation of high-latitude boundary layer mixed-phase cloud in the ECMWF global model. Monthly Weather Review, 142(9), 3425-3445.
Hogan, R. J., & Bozzo, A. (2018). A flexible and efficient radiation scheme for the ECMWF model. Journal of Advances in Modeling Earth Systems, 10(8), 1990-2008.
Mason, S. L., Cole, J. N., Docter, N., Donovan, D. P., Hogan, R. J., HĂĽnerbein, A., … & van Zadelhoff, G. J. (2023). An intercomparison of EarthCARE cloud, aerosol and precipitation retrieval products. EGUsphere, 2023, 1-34.
Qu, Z., Barker, H. W., Cole, J. N., & Shephard, M. W. (2022). Across-track extension of retrieved cloud and aerosol properties for the EarthCARE mission: the ACM-3D product. Atmospheric Measurement Techniques Discussions, 2022, 1-28.
Wehr, T., Kubota, T., Tzeremes, G., Wallace, K., Nakatsuka, H., Ohno, Y., … & Bernaerts, D. (2023). The EarthCARE mission–science and system overview. Atmospheric Measurement Techniques, 16(15), 3581-3608.
Zelinka, M. D., Myers, T. A., McCoy, D. T., Po-Chedley, S., Caldwell, P. M., Ceppi, P., et al. (2020). Causes of higher climate sensitivity in CMIP6 models. Geophysical Research Letters, 47, e2019GL085782. https://doi.
For more Information about the topics and the co-financial partner (found by the lab !); contact Directeur de thèse – dominique.bouniol@meteo.fr
Then, prepare a resume, a recent transcript and a reference letter from your M2 supervisor/ engineering school director and you will be ready to apply online before March 14th, 2025 Midnight Paris time !
Profil
Experience remote sensing, physical processes or atmospheric models, ideally with a connection to clouds or radiation. Experience in programming and handling observational datasets.
Laboratoire
CNRM
Message from PhD team
More details on CNES website : https://cnes.fr/fr/theses-post-doctorats
