Disk-Integrated Earth's Outgoing Longwave Radiation Viewed From a Moon-Based Platform: Model Simulations

A Moon-based sensor can observe the Earth as a single point and achieve disk-integrated measurements of outgoing longwave radiation (OLR), which significantly differs from low orbital, geostationary, and Sun-Earth L1 point platforms. In this study, a scheme of determining the disk-integrated Earth's OLR based on a Moon-based platform is proposed. The observational solid angle was theoretically derived based on the Earth's ellipsoid model and the disk-integrated observational anisotropic factor was estimated to eliminate the effects of the Earth's radiant anisotropy. The simulated disk-integrated Earth's OLR obtained from a Moon-based platform varies periodically, due to changes in the observation geometry and Earth's scene distribution within the observed Earth's disk. Clouds, meteorological parameters, and the land cover distribution notably affect the disk-integrated Earth's OLR. By analyzing the disk-integrated Earth's OLR from a Moon-based platform, significant variabilities were investigated. Additionally, the Earth's shape and radiant anisotropy that affecting the disk-integrated Earth's OLR were estimated. In conclusion, a more realistic Earth's shape, the latest version of the angular distribution model (ADM), and accurate land cover and meteorological datasets are needed when determining the disk-integrated Earth's OLR. It is expected the unique variability captured by this platform and its ability to complement traditional satellite data make it a valuable tool for studying Earth's radiation budget and energy cycle, and contributing to diagnostic of the climate General Circulation Models (GCM) performance. Observing large-scale geoscience phenomena poses a significant challenge, necessitating observations that guarantee spatial continuity and temporal consistency. Equipping sensors on the lunar surface can observe the whole Earth's disk, which is a feasible way to complement the existing satellites. Determining the disk-integrated Earth's OLR from a Moon-based platform helps in exploring its potential for detecting geoscience phenomena at different scales. Our study finds that the Moon-based disk-integrated Earth's OLR would provide full coverage of the whole Earth's phase angle during one sidereal month. The day-night and land-ocean effects on the Moon-based disk-integrated OLR during one sidereal month would provide substantial variability to compare to similarly sampled GCM output comparison that is not available from conventional satellite data. Such these unique variabilities in the Moon-based disk-integrated Earth's OLR make the Moon a valuable Earth observation platform for studying Earth's radiation budget and energy cycle, and evaluating the performance of GCMs. Disk-integrated Earth's outgoing longwave radiation are estimated considering Earth's shape and radiant anisotropy Overall understanding of the variability on Moon-based disk-integrated Earth's outgoing longwave radiation Discussing the characteristics of Moon-based disk-integrated Earth's outgoing longwave radiation