![]() ![]() Furthermore, parallel observations of R s at BSRN stations can compensate for each other to improve the data continuity (Augustine & Dutton, 2013). High-accuracy instruments have been deployed at the BSRN stations, with good maintenance protocols and frequent calibration (Augustine & Dutton, 2013 K. Accordingly, to improve the instrumental accuracy, the Baseline Surface Radiation Network (BSRN) was established during the early 1990s (Ohmura et al., 1998) to independently measure R s and its diffuse and direct components according to the specifications of the World Climate Research Programme. For example, R s observations in China suffer from substantial inhomogeneity issues due to instrument replacement and instrument sensitivity drift (K. However, the uncertainties in such R s data are difficult to quantify (Wild, 2009). Ground-based observations of R s collected at weather stations since the 1950s, such as those from the Global Energy Balance Archive (GEBA), provide key evidence for global dimming and brightening (Ohmura et al., 1989 Wild et al., 2017). These phenomena have become an important consideration for research on the Earth's energy and water cycles (Long et al., 2009 Roderick & Farquhar, 2002). Ground-based observations of R s have indicated a continuous decrease from the 1950s to the 1980s and an increase thereafter, a trend that is known as “global dimming and brightening” (Augustine & Dutton, 2013 Dutton et al., 2006 Ohring et al., 2008 Stanhill & Cohen, 2001 K. However, R s is not constant rather, it undergoes significant decadal variations (Wild, 2009). Key PointsĪs the Earth's primary energy source, the surface incident solar radiation ( R s) plays an important role in climate change (Dorno, 1920 Mercado et al., 2009 Sellers et al., 1990). Trends in R s from 1923 to 1950 are also found over Europe (1.91 W/m 2 per decade) and the United States (−1.31 W/m 2 per decade), but the results in Europe may not well represent the actual trend for the European continent due to poor spatial sampling. ![]() Even if 1994–2010 is well known as a period of global brightening, the observed and SunDu-derived R s over China still exhibit declining trends. Our revised results from ~2,600 stations show global dimming from the 1950s to the 1980s over China (−1.90 W/m 2 per decade), Europe (−1.36 W/m 2 per decade), and the United States (−1.10 W/m 2 per decade), brightening from 1980 to 2009 in Europe (1.66 W/m 2 per decade) and a decline from 1994 to 2010 in China (−1.06 W/m 2 per decade). Based on direct comparisons of ~200 observed and sunshine duration (SunDu) derived R s station pairs, meeting data record lengths exceeding 60 months and spatial distances less than 110 km, we show that meteorological observations of SunDu can be used as a proxy for measured R s. ![]() This claim has been questioned due to the inhomogeneity and low spatial-temporal coverage of R s observations. Observations show that the surface incident solar radiation ( R s) decreased over land from the 1950s to the 1980s and increased thereafter, known as global dimming and brightening. ![]()
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