Near-global monitoring of surface solar radiation through the construction of a geostationary satellite network observation system
Dear Editor,
Surface solar radiation (SSR) refers to the solar shortwave radiation (SWR) that reaches the Earth’s surface, serving as the primary energy source for life on our planet and the major force in land surface models.1,2 Variations in SSR can affect climate change, plant photosynthesis, and solar energy utilization.3 Satellite remote sensing, characterized by its robust data continuity and extensive coverage, stands out as one of the most effective means for monitoring changes in SSR.4 However, even the current state-of-the-art satellite SSR products, such as Clouds and the Earth’s Radiant Energy System (CERES) and the International Satellite Cloud Climatology Project, have spatial resolutions that are limited to only a few hundred kilometers, which significantly hinders the refined observation and application of SSR.
We previously developed a monitoring system that uses a single geostationary satellite to retrieve SSR with new benchmark accuracy, enhanced spatial and temporal resolution (STR), and comprehensive information on SSR composition (SSRC) from across the East Asia-Pacific (EAP) region.5 This system captures the SSRC, including SWR (0.3–3 μm), photosynthetically active radiation (PAR; 0.4–0.7 μm), ultraviolet A (UVA; 0.315–0.4 μm), and UVB (0.28–0.315 μm), as well as their direct and diffuse components in the EAP area simultaneously. However, it is worth noting that utilizing a single geostationary satellite limits the observation coverage to a specific area.
Introduction of a geostationary satellite network observation system
Building upon a unified satellite inversion framework, we propose a synergistic approach to SSR monitoring by integrating the geostationary satellite network observation (GSNO) system, introducing a novel concept for SSRC monitoring on a near-global scale (Figure 1A). The GSNO system consists of four geostationary satellites—the Chinese FY-4A/B, Japanese Himawari-8 (H-8), European MSG, and American GOES-16—positioned at approximately 105°E, 140°E, 41.5°E, and 75°W, respectively. By combining observations from multiple geostationary satellites across different locations, SSRC monitoring can achieve an unprecedented level of spatial resolution, reaching the kilometer scale, and temporal resolution at an hourly scale across near-global regions. Compared to numerical simulations and polar-orbiting satellite observations, the GSNO system enables the capture of finer variation characteristics of SSRC with higher accuracy, thereby effectively revealing information about the Earth’s surface energy balance process.
