Radiation Fluxes in a Business District of Shanghai, China

AbstractRadiative fluxes are key drivers of surface–atmosphere heat exchanges in cities. Here the first yearlong (December 2012–November 2013) measurements of the full radiation balance for a dense urban site in Shanghai, China, are presented, collected with a CNR4 net radiometer mounted 80 m above ground. Clear-sky incoming shortwave radiation K↓ (median daytime maxima) ranges from 575 W m−2 in winter to 875 W m−2 in spring, with cloud cover reducing the daily maxima by about 160 W m−2. The median incoming longwave radiation daytime maxima are 305 and 468 W m−2 in winter and summer, respectively, with increases of 30 and 15 W m−2 for cloudy conditions. The effect of air quality is evident: haze conditions decrease hourly median K↓ by 11.3%. The midday (1100–1300 LST) clear-sky surface albedo α is 0.128, 0.141, 0.143, and 0.129 for winter, spring, summer, and autumn, respectively. The value of α varies with solar elevation and azimuth angle because of the heterogeneity of the urban surface. In winter, sha...