In this article, we comprehensively assessed the newly released long-term high-spatial-resolution Global LAnd Surface Satellite (GLASS) surface longwave (LW) radiation product using site measurements of LW fluxes. In total, three years of ground-measured LW fluxes (surface longwave upward radiation (LWUP), surface longwave downward radiation (LWDN), and surface longwave net radiation (LWNR) collected from 141 sites in six independent networks (AmeriFlux, AsiaFlux, BSRN, CEOP, HiWATER-MUSOEXE, and TIPEX-III) are used to evaluate the GLASS LW radiation product. These sites cover various land cover types, surface elevations, and climatic types. According to the evaluation results, the biases are –4.33, –3.77, and 0.70 W/m2 and the RMSEs are 18.15, 26.94, and 26.70 W/m2 for clear-sky LWUP, LWDN, and LWNR, respectively. The GLASS LW radiation product performs well in climate-change-sensitive areas such as poleward areas, semiarid areas, and the “third pole”, namely, the Tibetan Plateau. The accuracy of the GLASS LW product is higher or comparable to that of available LW products and studies but has a high-spatial-resolution of 1 km and a time span of 19 years. In conclusion, the overall accuracy of the clear-sky GLASS LW radiation product can satisfy the requirements of the hydrological, meteorological, and agricultural research communities on a global scale. We will continue to improve the retrieval algorithms and update the products accordingly.

中文翻译：

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使用地面测量评估长期高空间分辨率全球陆地和地面卫星 (GLASS) 地面长波辐射产品

在本文中，我们使用 LW 通量的现场测量，全面评估了新发布的长期高空间分辨率全球陆地和地面卫星 (GLASS) 地面长波 (LW) 辐射产品。总共从 6 个独立网络（AmeriFlux、AsiaFlux、BSRN）的 141 个站点收集了三年地面测量的 LW 通量（地表长波向上辐射 (LWUP)、地表长波向下辐射 (LWDN) 和地表长波净辐射 (LWNR)） , CEOP, HiWATER-MUSOEXE, and TIPEX-III) 用于评估 GLASS LW 辐射产品。这些站点覆盖了各种土地覆盖类型、地表高程和气候类型。根据评估结果，偏差为 –4.33, – 3.77 和 0.70 W/m2，晴天 LWUP、LWDN 和 LWNR 的 RMSE 分别为 18.15、26.94 和 26.70 W/m2。GLASS LW辐射产品在极地、半干旱地区和“第三极”青藏高原等气候变化敏感地区表现良好。GLASS LW 产品的精度高于或可与现有 LW 产品和研究相媲美，但具有 1 公里的高空间分辨率和 19 年的时间跨度。综上所述，晴空 GLASS LW 辐射产品的整体精度可以满足全球范围内水文、气象和农业研究界的要求。我们将继续改进检索算法并相应地更新产品。GLASS LW 产品的精度高于或可与现有 LW 产品和研究相媲美，但具有 1 公里的高空间分辨率和 19 年的时间跨度。综上所述，晴空 GLASS LW 辐射产品的整体精度可以满足全球范围内水文、气象和农业研究界的要求。我们将继续改进检索算法并相应地更新产品。GLASS LW 产品的精度高于或可与现有 LW 产品和研究相媲美，但具有 1 公里的高空间分辨率和 19 年的时间跨度。综上所述，晴空 GLASS LW 辐射产品的整体精度可以满足全球范围内水文、气象和农业研究界的要求。我们将继续改进检索算法并相应地更新产品。