Seasonal Variation of Mass Absorption Efficiency of Elemental Carbon in the Four Major Emission Areas in China

Zhenyu Xing ； Junjun Deng ； Chao Mu ； Yang Wang ； Ke Du

《Aerosol and Air Quality Research》 14卷7期 (2014/12) Pp. 1897-1905(i-xi)

並列摘要

As an important site-specific optical parameter widely used in climate models, the mass absorption efficiency (MAE) of elemental carbon (EC), varies dramatically with the source types and governs the direct radiative forcing (DRF) estimation. In this study, the MAE of EC for ambient samples collected from four major emission areas in China, i.e., Beijing-Tianjin-Hebei area (BTH), Yangtze River Delta area (YRD), Sichuan Basin area (SB), and Pearl River Delta area (PRD), as well as emissions from burning of residential honeycomb briquette, firewood and rice straw were investigated by using a filter-based method. The annual mean MAE_(EC) over the four major emission areas is 7.51 m^2/g. MAE_(EC) in BTH and YRD during summer appears significantly higher than MAE_(EC) in other seasons, while seasonal variations of MAE_(EC) in SB and PRD suggest MAE_(EC) in summer and autumn is higher than that in winter and spring. MAE_(EC) for samples from fossil fuels burning and biomass open-burning is 2.10 times higher than that from residential biofuel burning, which could be one of the reasons for the higher MAE_(EC) values during the seasons heavily affected by fossil fuels burning and biomass open-burning (i.e., summer and autumn) than winter for the four locations. Difference between the measured and AeroCom median value of MAE_(EC) may cause underestimation of DRF_(EC) over the studied area by a factor of 0.13. Spatial and temporal variations of MAE_(EC) would also result in underestimations of DRF_(EC) to different degrees varying with seasons and areas.

並列關鍵字

Mass absorption efficiency ； Elemental carbon ； Seasonal variability ； Direct radiative forcing