EGUsphere EGUsphere EGUsphere EGUsphere Copernicus Publications Göttingen, Germany 10.5194/egusphere-2026-4324 Initial generation and validation of the JAXA four-sensor synergy radiation budget product (ALL_RAD) for the EarthCARE mission Nagao Takashi M. https://orcid.org/0000-0002-5314-0352 1 Suzuki Kentaroh https://orcid.org/0000-0001-5315-2452 2 Yamauchi Akira 3 Oikawa Eiji https://orcid.org/0000-0001-5394-0299 1 Sekiguchi Miho https://orcid.org/0000-0003-2254-6429 4 Ishida Haruma 2 Muto Masataka https://orcid.org/0009-0000-3457-2136 3 Meteorological Research Institute, Japan Meteorological Agency, Tsukuba, Japan Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan Japan Aerospace Exploration Agency, Tsukuba, Japan Faculty of Marine Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan 13 08 2026 2026 1 36 Copyright: © 2026 Takashi M. Nagao et al. 2026 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4324/ The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4324/egusphere-2026-4324.pdf

The Earth Cloud, Aerosol and Radiation Explorer (EarthCARE) mission provides an unprecedented opportunity to investigate the Earth’s radiation budget using synergistic observations from active and passive sensors. In this study, we present the development and validation of the JAXA four-sensor synergy radiation budget product (ALL_RAD), version Ba, which was publicly released on 1 December 2025. The ALL_RAD algorithm generates composite cloud and aerosol profiles by integrating Level-2 retrieval products from the Cloud Profiling Radar (CPR), the Atmospheric Lidar (ATLID), and the Multi-Spectral Imager (MSI), and then estimates broadband shortwave and longwave radiative fluxes and heating rate profiles using a one-dimensional radiative transfer model. The performance of ALL_RAD is evaluated against the ESA radiative flux product (BMA-FLX) derived from broadband radiometer (BBR) observations. The comparison shows substantial improvements in radiative flux estimates relative to earlier pre-launch evaluations, with instantaneous shortwave bias and root-mean-square error (RMSE) reduced to −0.6 and 33.7 W m⁻², respectively, and the longwave bias and RMSE reduced to +2.2 and 8.1 W m⁻², respectively. In addition, comparisons with ground-based observations from the Baseline Surface Radiation Network (BSRN) demonstrate good agreement for both shortwave and longwave surface fluxes. The physical consistency of the product is further assessed using cloud radiative effects and associated heating rate profiles as well as aerosol radiative effects, which are found to be broadly consistent with previous studies using A-Train observations. Future work will extend the validation to longer periods and broader cloud regimes, and will further assess uncertainty sources related to aerosol representation, spatial representativeness, and three-dimensional radiative effects. Overall, ALL_RAD provides a reliable basis for estimating EarthCARE radiative fluxes and derived quantities, thus establishing a foundation for radiative closure studies using EarthCARE observations.

 Japan Aerospace Exploration Agency EO-RA4 (Research Announcement on the Earth Observations) Ministry of Education, Culture, Sports, Science and Technology JPMXD0722680395