Abstract This study uses the second Modern-Era Retrospective Analysis for Research and Applications (MERRA-2) reanalysis product to analyze the all-sky surface solar radiation (SSR) over the Yangtze River basin (YRB) and the quantitative impact of main factors from 1980 to 2018. Radiation data and multiple atmospheric factors were inputted into a multiple linear regression model. The regression results showed that aerosols and total clouds were the dominant factors affecting annual SSR variation. The aerosol radiative effect (ARE) and cloud radiative effect (CRE) were then calculated to quantify the effects of aerosols and clouds on SSR based on the MERRA-2 dataset. The average ARE and CRE in the YRB was −10.70 ± 2.01 and −47.92 ± 2.31 W/m2, respectively, which means that clouds attenuate SSR more than aerosols. SSR showed a general decline throughout the region (−0.156 W/m2 per year) and decreased significantly in the Sichuan Basin (SB, −0.242 W/m2 per year). The enhanced weakening of the radiative cooling effect of aerosols and clouds determines the decrease in the SSR. In Central China (CC), ARE had significantly enhanced (−0.297 W/m2 per year) and CRE had significantly weakened (0.207 W/m2 per year). From 1980 to 1990, the SSR in the Western Sichuan Plateau (WSP) increased by 0.329 W/m2 per year, affected by the decrease in aerosol and cloud, in which low clouds and dust aerosols played an important role. The SSR in SB was reduced due to the significant increase in sulfate, black carbon, and organic carbon aerosols. And aerosols in Yangtze River Delta (YRD) have important effects on SSR, while clouds were dominant for CC. From 1991 to 2018, the dominant factor influencing the SSR in WSP, SB, and CC was cloud, while the SSR in YRD was mainly determined by aerosols. From 2008 to 2018, the SSR in WSP significantly decreased by −1.188 W/m2 per year, mainly due to the increase in clouds. During this period, the SSR in YRD increases by 0.220 W/m2 per year, largely from the decrease of aerosols.

中文翻译：

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近40年来长江流域全天面太阳辐射及其影响因素调查

摘要 本研究利用第二代现代研究与应用回顾性分析（MERRA-2）再分析产品分析了长江流域（YRB）的全天表面太阳辐射（SSR）及其主要因素的定量影响。 1980年至2018年。将辐射数据和多个大气因素输入多元线性回归模型。回归结果表明，气溶胶和总云量是影响 SSR 年变化的主要因素。然后计算气溶胶辐射效应 (ARE) 和云辐射效应 (CRE)，以根据 MERRA-2 数据集量化气溶胶和云对 SSR 的影响。YRB 的平均 ARE 和 CRE 分别为 -10.70 ± 2.01 和 -47.92 ± 2.31 W/m2，这意味着云对 SSR 的衰减大于气溶胶。整个地区的 SSR 普遍下降（-0.156 W/m2 每年），四川盆地显着下降（SB，-0.242 W/m2 每年）。气溶胶和云的辐射冷却效应的增强减弱决定了 SSR 的降低。在华中 (CC)，ARE 显着增强（-0.297 W/m2 每年），而 CRE 显着减弱（0.207 W/m2 每年）。1980—1990年，受气溶胶和云量减少的影响，川西高原（WSP）的SSR每年增加0.329 W/m2，其中低云和沙尘气溶胶发挥了重要作用。由于硫酸盐、黑碳和有机碳气溶胶的显着增加，SB 中的 SSR 降低。长三角地区气溶胶对 SSR 有重要影响，而云对 CC 有显着影响。从 1991 年到 2018 年，影响 WSP、SB 和 CC 的 SSR 的主导因素是云，而 YRD 的 SSR 主要由气溶胶决定。从 2008 年到 2018 年，WSP 中的 SSR 每年显着下降 -1.188 W/m2，主要是由于云的增加。在此期间，长三角地区 SSR 每年增加 0.220 W/m2，主要来自气溶胶的减少。