Eddy covariance measurements with high-resolution time-of-flight aerosol mass spectrometry: a new approach to chemically resolved aerosol fluxes
Eddy covariance measurements with high-resolution time-of-flight aerosol mass spectrometry: a new approach to chemically resolved aerosol fluxes
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DOI：
10.5194/amt-4-1275-2011
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发表时间：
2011-01-01
影响因子：
3.8
通讯作者：
Jimenez, J. L.
中科院分区：
文献类型：
--
作者：
Farmer, D. K.;Kimmel, J. R.;Jimenez, J. L.
虽然实验室研究表明，生物源挥发性有机化合物（VOCs）产生大量的二次有机气溶胶（SOA），生产的生物源SOA向上通量所指示的尚未最终观察到的森林。此外，虽然已知气溶胶存款到表面，但几乎没有技术提供化学分辨的颗粒沉积通量。为了更好地约束气溶胶源和汇，我们已经开发了一种新的技术，直接测量通量的化学分辨亚微米气溶胶使用高分辨率飞行时间气溶胶质谱仪（HR-AMS）在一个新的，快速涡度协方差模式。这种方法利用了仪器的能力，定量识别有机和无机成分，包括铵，硫酸盐和硝酸盐，在几个Hz的时间分辨率。新的方法已成功部署在温带黄松种植园在加州在BEARPEX-2007运动，提供总的和化学解决非耐火（NR）PM 1通量。中午NR-PM 1气溶胶总量的平均沉降速度为2.05 +/- 0.04 mm s（-1）。使用NH 2+和NH3+碎片的高分辨率测量，我们展示了颗粒铵的第一个涡动协方差通量测量，其显示中午时间的沉积速度为1.9 +/- 0.7 mm s（-1），并且主要由硫酸铵的沉积。
Although laboratory studies show that biogenic volatile organic compounds (VOCs) yield substantial secondary organic aerosol (SOA), production of biogenic SOA as indicated by upward fluxes has not been conclusively observed over forests. Further, while aerosols are known to deposit to surfaces, few techniques exist to provide chemically-resolved particle deposition fluxes. To better constrain aerosol sources and sinks, we have developed a new technique to directly measure fluxes of chemically-resolved submicron aerosols using the high-resolution time-of-flight aerosol mass spectrometer (HR-AMS) in a new, fast eddy covariance mode. This approach takes advantage of the instrument's ability to quantitatively identify both organic and inorganic components, including ammonium, sulphate and nitrate, at a temporal resolution of several Hz. The new approach has been successfully deployed over a temperate ponderosa pine plantation in California during the BEARPEX-2007 campaign, providing both total and chemically resolved non-refractory (NR) PM1 fluxes. Average deposition velocities for total NR-PM1 aerosol at noon were 2.05 +/- 0.04 mm s(-1). Using a high resolution measurement of the NH2+ and NH3+ fragments, we demonstrate the first eddy covariance flux measurements of particulate ammonium, which show a noon-time deposition velocity of 1.9 +/- 0.7 mm s(-1) and are dominated by deposition of ammonium sulphate.