Aging of biomass burning aerosols over West Africa: Aircraft measurements of chemical composition, microphysical properties, and emission ratios
Aging of biomass burning aerosols over West Africa: Aircraft measurements of chemical composition, microphysical properties, and emission ratios
复制标题
DOI：
10.1029/2008jd009845
复制
发表时间：
2008-10-30
影响因子：
4.4
通讯作者：
Coe, H.
中科院分区：
文献类型：
--
作者：
Capes, G.;Johnson, B.;Coe, H.
本文利用英国空中大气测量设施飞机的数据，研究了西非生物质燃烧气溶胶的物理和化学特性。在2006年1月和2月的尘埃和生物质燃烧实验（DABEX）和尘埃流出和沉积到海洋（DODO）现场实验期间，对生物质燃烧气溶胶进行了测量。在整个区域观察到老化生物质燃烧气溶胶层，在低海拔烟羽穿透期间遇到新鲜生物质燃烧气溶胶。图中显示了整个区域气溶胶特性的垂直分布。Aerodyne四极杆气溶胶质谱仪（Q-AMS）的测量结果显示了在数千公里的区域内，新鲜和老化生物质燃烧气溶胶之间的化学成分变化。这些数据是首次观察到生物质燃烧气溶胶成分的大陆尺度变化。然而，在整个区域观察到有机气溶胶质量浓度和一氧化碳浓度之间几乎呈线性关系。由于化学处理和有机物质重新分配到气相的结合，在该区域的气溶胶寿命期间发生净碳损失。观察到数量尺寸分布的演变，得出的结论是凝结是主要过程，这一发现得到了凝结箱建模的支持。在西非，全球最大的生物质燃烧来源之一，区域尺度的有机碳（0.041）和黑碳（0.0072）相对于CO的排放比率已经得到估计。西非萨赫勒地区的生物质燃烧排放量在文献中的代表性很差，这些与其他地区的文献值。
This paper investigates the physical and chemical characteristics of biomass burning aerosol over West Africa using data from the UK Facility for Airborne Atmospheric Measurements aircraft. Measurements of biomass burning aerosol were made during the Dust and Biomass-burning Experiment (DABEX) and Dust Outflow and Deposition to the Ocean (DODO) field experiments in January and February 2006. Layers of aged biomass burning aerosols were observed throughout the region, and fresh biomass burning aerosols were encoutered during the penetration of smoke plumes at low altitudes. Vertical profiles of aerosol properties across the region are shown. Measurements from an Aerodyne Quadrupole Aerosol Mass Spectrometer (Q-AMS) show changes in chemical composition between fresh and aged biomass burning aerosols, over a region spanning thousands of kilometers. These data represent the first time that continental-scale variability in biomass burning aerosol composition has been observed. However, an almost linear relationship between organic aerosol mass concentration and carbon monoxide concentration was observed across the region. A net carbon loss occurs over the aerosol lifetime in the region owing to a combination of chemical processing and repartitioning of organic mass to the gas phase. Evolution of the number size distribution was observed, with coagulation concluded to be dominant process involved, a finding supported by coagulation box modeling. Regional-scale emission ratios for organic (0.041) and black carbon (0.0072) with respect to CO have been estimated over West Africa, one of the Largest sources of biomass burning globally. Biomass burning emissions from the West African Sahel are poorly represented in the literature, and these with literature values from other regions.