Regional Interdecadal Drivers of Surface Solar Radiation Derived from Homogenized SSR Dataset

  Our research group is glad to announce that the manuscript Evolution and drivers of surface solar radiation over China since the mid-20th century, with Anna Li as the first author and Prof. Qingxiang Li as the corresponding author, has been accepted for publication in the authoritative peer-reviewed journal Climate Dynamics.

Surface solar radiation (SSR) serves as the fundamental energy source of the Earth’s climate system, and an interdecadal “dimming-brightening” transition has been widely observed globally. Nevertheless, the regional disparities of such transition across China, as well as the quantitative contributions of clouds and diverse aerosols to SSR variations, remain insufficiently understood. Based on the newly homogenized global SSR dataset SSRIH20CR, this study integrates two complementary attribution frameworks, namely linear Partial Least Squares Regression (PLSR) and nonlinear Random Forest with SHapley Additive exPlanations (SHAP) algorithm. After eliminating the interannual noise induced by total cloud cover, we systematically quantify the relative impacts of total cloud cover, total column water vapor and multiple aerosol precursors on centennial SSR variations nationwide and in three subregions (Eastern, Northeast and Western China).

Our results reveal that national SSR exhibits a consistent long-term dimming-to-brightening shift from 1961 to 2018, while dominant driving factors differ drastically between eastern and western China. Total cloud cover only modulates year-to-year SSR fluctuations and contributes merely around 4.1% to decadal trends. At the national scale, organic carbon (24.7%), black carbon (22.3%) and sulfur dioxide (13.7%) are the dominant aerosol drivers, whereas total column water vapor exerts negligible long-term influences below 5%. SSR variability in eastern China is mainly controlled by scattering aerosols including sulfur dioxide and organic carbon, while ammonia, organic carbon and black carbon jointly dominate western regions; the spatial divergence of anthropogenic emission patterns accounts for such regional distinctions. Besides, black carbon can counteract part of the dimming effect of scattering aerosols via its semi-direct radiative effect, demonstrating complicated interactive aerosol radiative mechanisms. This work establishes an integrated linear-nonlinear statistical attribution workflow and clarifies the anthropogenic mechanisms behind China’s dimming and brightening episodes, delivering solid observational evidence and theoretical references for regional air quality management, photovoltaic energy exploitation and climate projection. Supported by the National Key R&D Program of China and the National Natural Science Foundation, this research involves collaborators from the Institute for Atmospheric and Climate Science, ETH Zurich.