大气气溶胶成分的改变对空气污染以及气候变化都有重要影响。遥感能在不破坏气溶胶自然状态的前提下探测气溶胶的成分特性。基于OPAC(optical properties of aerosols and clouds)模型对黑碳(BC)、水溶成分(WASO)、不可溶成分(INSO)、沙尘(DUST)四种气溶胶成分的微物理和光学特性的描述,利用太阳-天空辐射计获取的地基遥感观测,对2014年北京APEC会议前、会中、会后的气溶胶各成分含量及其光学厚度进行定量反演研究。结果显示,APEC会前、会中、会后的光学厚度(440 nm)平均值分别是0.72、0.25、0.57,会中的气溶胶光学厚度明显小于会前和会后,其中INSO成分的光学厚度贡献占主导地位。APEC会前BC、WASO、INSO、DUST质量浓度分别为0.8 mug/m~3、139.6 mug/m~3、184.2 mug/m~3、194.3 mug/m~3,APEC会中四种成分质量浓度分别为1.1mug/m~3、56.4 mug/m~3、40.3 mug/m~3、7.8 mug/m~3, APEC会后质量浓度分别为1.0 mug/m~3、126.6 mug/m~3、157.1 mug/m~3、30.9 mug/m~3,除了BC成分在会议期间无显著变化外,会中WASO、INSO、DUST成分的质量浓度数值明显低于会前和会后,这说明APEC会议期间北京地区采取的保障措施对空气质量提升起到了较好的作用。利用AE-51黑碳仪对反演的BC质量浓度进行验证,发现遥感反演的BC质量浓度与在位观测具有良好的一致性,相关系数R~2=0.68。
英文摘要:
Variation of aerosol components impact greatly on air pollution and climate change, and remote sensing is able to detect aerosol composition properties while maintaining the natural states of ambient aerosol. Based on microphysical and optical properties of black carbon (BC), water soluble component (WASO), insoluble component (INSO) and mineral dust (DUST) provided by optical properties of aerosols and clouds (OPAC) model, mass concentration of the four components were retrieved and their contributions to total aerosol optical depth were calculated by using aerosol properties acquired from ground-based sun-sky radiometer measurements during APEC Forum days in Beijing in 2014. Results show that the average AOD (440 nm) on APEC Forum days (0.25) is much lower than that of pre-Forum days (0.72) and post-Forum days (0.57), and WASO dominantly contributes to the total aerosol optical depth. Mass density of BC, WASO, INSO, DUST is respectively 0.8 mug/m~3,139.6 mug/m~3,184.2 mug/m~3,194.3 mug/m~3 on pre-Forum days,1.1 mug/m~3, 56.4 mug/m~3,40.3 mug/m~3, 7.8 mug/m~3 on APEC Forum days, and 1.0 mug/m~3, 126.6 mug/m~3, 157.1 mug/m~3,30.9 mug/m~3 on post-Forum days. BC mass density doesn't change much during APEC Forum, while the numeric numbers of mass densities of WASO, INSO, and DUST in APEC Forum days are much lower compared to those of pre-Forum days and post-Forum days. This illustrates clearly that the control measures for improving air quality undertaken by the government have been taking effect during APEC Forum days. In-situ measurements of BC concentration were used by aethalometer to verify the BC retrieval and find that the retrieved BC mass concentration agrees well with measured content with the correlation coefficient R~2 of 0.68.