资源环境科技发展态势分析平台

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. This claim has been questioned due to the inhomogeneity and low spatial-temporal coverage of R-s observations. Based on direct comparisons of similar to 200 observed and sunshine duration (SunDu) derived R-s station pairs, meeting data record lengths exceeding 60months and spatial distances less than 110 km, we show that meteorological observations of SunDu can be used as a proxy for measured R-s. Our revised results from similar to 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). 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. Trends in R-s from 1923 to 1950 are also found over Europe (1.91W/m(2) per decade) and the United States (-1.31W/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.

Plain Language Summary Ground-based observations of the surface incident solar radiation (R-s) reveal the phenomena known as global dimming and brightening, that is, a downtrend over land from the 1950s to the 1980s and an uptrend thereafter. However, R-s observations suffer from inhomogeneity issues and low spatial-temporal coverage. Sunshine duration-derived R-s is not present above problems and was utilized here to compare with observed R-s from China, Europe, and the United States over the 1950-2010 common period. Results show a good agreement between two data sets except for the dimming period in China, mainly due to instrument sensitivity drift of R-s observations. Therefore, using more extensive sunshine duration-derived R-s data set at approximately 2,600 stations over China, Europe, and the United States since 1901, a revisit of global dimming and brightening has been reasonably conducted, including the early period prior to the 1950s.