## 4 Conclusions
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app121910176/s1](https://www.mdpi.com/article/10.3390/app121910176/s1)]([https://www.mdpi.com/article/10.3390/app121910176/s1](https://www.mdpi.com/article/10.3390/app121910176/s1)), Figure S1: Global distribution of: (a) Global Energy Balance Archive (GEBA) 1397 stations and (b) Baseline Surface Radiation Network (BSRN) 73 stations, whose surface solar radiation (SSR) data (availability in years indicated in the colorbars) have been used in the study; Figure S2: Time periods covered by measurements of each station for (i) GEBA and (ii) BSRN networks. (a) Total number of stations since 1980 and (b) Number of available stations after applying criteria to compute linear slopes, i.e., 232 GEBA and 22 BSRN stations; Figure S3: Seasonal variation of hemispherical mean correlation coefficient R between MERRA-2 and GEBA (blue color) and between MERRA-2 and BSRN (red color) stations, computed using SSR fluxes for the North Hemisphere (i) and the South Hemisphere (ii); Figure S4: Global distribution of correlation coefficient between MERRA-2 and each GEBA (i, left column) and BSRN (ii, right column) station SSR fluxes; Figure S5: Histogram of frequency distribution of correlation coefficient R (a), bias (b), relative bias (c), root mean squared error (RMSE) (d), relative RMSE (e),between MERRA-2 and GEBA (i, left column) and BSRN (ii, right column) stations. Results are computedusing MERRA-2, and GEBA and BSRN station SSR fluxes, except for R, which is computed using deseasonalized SSR anomalies. In the left y axis shown is given the number of stations, while in the right y axis the % number of stations; Figure S6: Agreement (blue dots) and disagreement (red dots) between trends of MERRA-2 and station SSR fluxes. The comparison is done for the associated deseasonalized anomalies for GEBA (left column, i) and BSRN (right column, ii) stations per selected time periods that are characterized as Global Dimming & Brightening periods (GDB phases). The embedded white x symbols indicate the statistically significant trends. The numbers in parentheses provide the total number of stations for which there is agreement/disagreement (first number) and the corresponding numbers for statistically significant trends (second number). The GDB phases ([PERSON] et al., WIREsClim Change 2016, 7:91-107) are: (a) 1980-1985, (b) 1986-200, (c) 2001-2010, (d) 2011-2017 for GEBA and (a) 1992-2000, (b) 2001-2010, (c) 2011-2020 for BSRN. Figure S7: Global distribution of MERRA-2 \(\Delta\)(SSR) anomalies over the 40-year period January 1980-December 2019, for (a) DJF, (b) MAM, (c) JJA, (d) SON. Reddish colors are those with positive trends (brightening), and those with bluish colors have negative trends (dimming). Statistically significant trends are indicated by black dots. Conceptualization, N.H.; methodology, N.H. and M.S. ; software, N.H., M.S. and M.B.K.-C.; validation, N.H., M.S. and M.B.K.-C.; formal analysis, M.S. ; investigation, N.H. and M.S. ; resources, N.H.; data curation, M.S. ; writing--original draft preparation, M.S. ; writing--review and editing, N.H., M.S., M.B.K.-C., M.W., I.V. and C.M. ; visualization, M.S. and M.B.K.-C.; supervision, N.H.; project administration, N.H.; funding acquisition, N.H. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. We acknowledge support of this work by the project \"Dioni: Computing Infrastructure for Big-Data Processing and Analysis.\" (MIS No. 5047222) which is implemented under the Action \"Reinforcement of the Research and Innovation Infrastructure\", funded by the Operational Programme \"Competitiveness, Entrepreneurship and Innovation\" (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund). Global dimming and brightening research at ETH Zurich got support from a sequence of Swiss National Science Foundation Grants (Grant Nos. 200021_135395, 200020_159938, 200020_188601).