Validation of EarthCARE products under ACROSS Mediterranean activities

The Mediterranean basin provides a complex aerosol-cloud environment for the exploitation EarthCARE's capabilities. For the validation of the EarthCARE products in the Mediterranean, the ACROSS validation activity will be implemented, which would increase synergies towards achieving the following objectives: (i) validate EarthCARE aerosol and cloud products using state-of-the-art ground-based and airborne facilities, (ii) implement science studies targeting radiative closures, ACI, and data assimilation experiments, (iii) and provide information for harmonizing and bridging past and future missions, to deliver Climate Data Records on aerosols and clouds. The rationale for ACROSS is based on lessons learned from the JATAC campaign in the Atlantic [1]. Following the JATAC example, we target to implement 3 Intensive Observational Periods, including large-scale field experiments in the Mediterranean. The suborbital component follows the ASKOS [2] example. It includes (i) ACTRΙS Aerosol and Cloud remote sensing facilities and high-precision radiation measurements (Potenza site in Italy, Limassol Cyprus, as well as Pyrgos, Thessaloniki, and PANGEA sites in Greece), (ii) radiation measurements for closure studies, (iii) UAV and aircraft in-situ flights collocated with the remote sensing measurements. ACROSS activities will be clustered with the ARCHIMEDES experimental activities in the Mediterranean, foreseen between late 2026 and late 2027. ACROSS seeks synergies with airborne activities. To this end, the first synergistic measurements were collected during the PERCUSION campaign in November 2024, during which HALO underpass two EarthCARE tracks close to the Thessaloniki and PANGEA sites. More airborne activities are envisioned in the Mediterranean area for Spring/September 2025/2026. ACROSS is a collaborative effort between NOA, AUTH, CNR-IMAA, ERATOSTHENES CoE, CUT, DLR, the University of Nova Gorica, CyI, INOE, FMI, PMOD, TROPOS, and LMU. The presentation will include validation of the ATLID L1 and L2 products with lidar ground-based measurements, and radiative transfer closure studies using BBR observations and collocated airborne radiation measurements from PERCUSION. The ACROSS team: E. Marinou1, V. Amiridis1, K.A. Voudouri1, D. Kouklaki1, M. Tsichla1, P. Paschou1, I. Tsikoudi1, A. Tsekeri1, A. Karipis1, I. Koutsoupi1, K. Rizos1, E. Giannakaki2, K. Papachristopoulou3, S. Kazadzis3, D. Balis4, G. Peletidou4, K. Michailidis4, A. Nemuc5, D. Nicolae5, G. Močnik6, M. Lenarčič6, F. Marenco7, M. Kezoudi7, A. Papetta7, S. Gross8, M. Wirth8, F. Ewald8, E. O Connor9, D. Moisseev9, V. Vakkari9, L. Mona10, N. Papagiannopoulos10, C.A. Papanikolaou10, M. Rosoldi10, R. Mamouri11,12, A. Nisantzi11,12, H. Baars13, A. Floutsi13, B. Mayer14, C. Emde14, and P. Kollias15,16. Affiliations: 1 National Observatory of Athens (NOA), Athens, Greece 2 University of Athens (UoA), Athens, Greece 3 Physics and Meteorology Observatorium of Davos, World Radiation Center, Davos, Switzerland 4 Aristotle University of Thessaloniki (AUTH), Thessaloniki, Greece 5 National Institute of Research & Development for Optoelectronics (INOE), Magurele, Romania 6 University of Nova Gorica (UNG), Slovenia 7 The Cyprus Institute (CyI), Nicosia, Cyprus 8 German Aerospace Center (DLR), Oberpfaffenhofen-Wessling, Germany 9 Finnish Meteorological Institute (FMI), Helsinki, Finland 10 Consiglio Nazionale delle Ricerche – Istituto di Metodologie per l’Analisi Ambientale (CNR-IMAA), Italy 11 ERATOSTHENES Centre of Excellence (ERATOSTHENES CoE), Limassol, Cyprus 12 Cyprus University of Technology (CUT), Limassol, Cyprus 13 Leibniz Institute for Tropospheric Research (TROPOS), Leipzig, Germany 15 Ludwig Maximilian University of Munich, Munich, Germany 14 Stony Brook University, Stony Brook, New York, United States 16 Department of Environmental and Climate Science, Upton, New York, United States References: [1] Fehr, T., et al., “The Joint Aeolus Tropical Atlantic Campaign 2021/2022 Overview—Atmospheric Science and Satellite Validation in the Tropics”, In Proceedings of the EGU General Assembly 2023, Vienna, Austria, 24–28 April 2023. https://doi.org/10.5194/egusphere-egu23-7249, 2023. [2] Marinou, E. et al., “An Overview of the ASKOS Campaign in Cabo Verde”. Environ. Sci. Proc., 26, 200. https://doi.org/10.3390/environsciproc2023026200, 2023. Acknowledgments: This research was financially supported by the PANGEA4CalVal project (Grant Agreement 101079201) funded by the European Union, and the CERTAINTY project (Grant Agreement 101137680) funded by the Horizon Europe program. Part of the work was financed through the Core Program within the Romanian National Research Development and Innovation Plan 2022-2027, carried out with the support of MCID, project no. PN 23 05.