A 41-Year Global All-Sky Surface Longwave Radiation Components Dataset at 5 km and hourly Resolution.

Longwave radiation (LWR) is a critical factor in surface energy balance and greenhouse effect studies, and its accurate measurement is essential for understanding climate change. However, existing remote sensing-based LWR products still have room for improvement in terms of spatiotemporal coverage, resolution, and accuracy. To address this issue, we developed the LWR Component of the global Long-term Earth System spatiotemporally Seamless Radiation budget dataset (LessRad). LessRad provides high-resolution (0.05°, hourly) LWR components including longwave downward radiation (LWDR), longwave upward radiation (LWUR), and longwave net radiation (LWNR). It extends the temporal coverage to 41 years (1982-2022) and outperforms existing comparable products. For LWDR and LWUR, rigorous validation against 565 ground-based observation sites demonstrates high accuracy, with correlation coefficients (R) of 0.94 and 0.97, biases of -4.39 W/m and -0.14 W/m, and root mean square errors (RMSE) of 24.74 W/m and 20.42 W/m, respectively. The high quality and extensive coverage make the LessRad LWR dataset an invaluable resource for fine-scale analysis of global surface radiation dynamics.