A harmonized surface-and-column climatological benchmark of brown carbon absorption across climate zones: dataset construction, preregistered structure testing, and graded robustness

We present a harmonized climatological benchmark of BrC absorption built from 3,042,607 quality-controlled window records (2010-01 onward), of which the 2010–2024 climatology window anchors the benchmark at 952 unique stations in 41 countries drawn from 22 contributed datasets. Three surface absorption calibers (EU44 provider decomposition, EBAS seven-wavelength self-decomposition, NOAA three-wavelength self-decomposition) and the AERONET column layer are processed under one quality-control and aggregation discipline, kept strictly separate, and stratified by climate zone × site type × season using dimensionless shape metrics (surface BrC absorption fraction f_BrC; column absorbing fraction absfrac440).