Direct climate effect of black carbon in China and its impact on dust storms

Dust storms originating in the Gobi desert and the surrounding areas critically impact weather, climate, and public health in China and neighboring Pacific Rim countries. In the decades between 1954 and 2007, reports of annual dust storm occurrences and the corresponding amount of total precipitation at 753 Chinese meteorological sites show a reduction in the occurrence and intensity of dust storms and clearly demonstrate an inverse relationship between the two. The correlation between dust storm occurrence and temperature in northwestern China also displays a negative trend but is less significant. Using a global climate model, we demonstrate that increased loading of light-absorbing aerosols in China, particularly black carbon ( BC), is the primary reason for precipitation and temperature increases over northwestern China, and the consequence of reductions in dust storm frequency and intensity. The model-simulated precipitation and temperature changes over northwestern China compare reasonably well with observed trends when a certain portion of BC has been added to the model, which significantly affects regional climate patterns through the heating of the air column. In addition to a reduction in dust storm intensity/frequency in response to an increase in BC, the model has also reproduced the substantial variability in precipitation which has been observed in other regions of China.