Study sites and data
We obtained the gap-filled 30-min data, including the four components of
radiation (DSR, USR, DLR, ULR; W∙m-2) and GPP
(g∙C∙m-2∙time-1), of 54 sites with
EC flux towers from FLUXNET
(https://fluxnet.org), OZflux (http://www.ozflux.org.au) and ChinaFlux
(http://www.chinaflux.org/) (Figure 2; Table S1). The dataset consists
of a total of 267 site-years and covers a wide range of vegetation
types, including tropical rainforests, subtropical evergreen forests,
temperate deciduous forests, coniferous forests, shrub lands, savannas
and grasslands, across North America, Europe, Asia and Australia. Each
ecosystem type includes at least three sites in different regions to
ensure its regional representativeness (Table S1). The instrumentation
information of each site is also outlined in Table S1.