Aerosol trends over China, 1980–2000

Annual emission trends of sulfur dioxide, black carbon, and organic carbon are presented for East Asia for the period 1980–2000. Emissions of sulfur dioxide peaked in about 1996, and emissions of the carbonaceous aerosols peaked in about 1994–1995, due to a variety of economic, environmental, and social forces. These emissions are converted to their contributions to aerosol optical depth (AOD) over East Asia, using regional results from the GOCART global chemical transport model. We calculate that, on average, AOD over China rose from a value of 0.25 in 1980, peaked at a value of about 0.305 in 1995–1996, and then decreased to about 0.29 in 2000. This trend is consistent with surface shortwave irradiance measurements at 52 weather stations in China, as well as with other radiation-related trends. It may also be consistent with a rise in mean surface temperatures in China starting about the middle of the 1990s.