Airborne measurement of OH reactivity during INTEX-B
Airborne measurement of OH reactivity during INTEX-B
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DOI：
10.5194/acp-9-163-2009
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发表时间：
2008-07
影响因子：
6.3
通讯作者：
J. Mao;X. Ren;W. Brune;J. Olson;J. Crawford;A. Fried;L. Huey;R. Cohen;B. Heikes;H. Singh
中科院分区：
文献类型：
--
作者：
J. Mao;X. Ren;W. Brune;J. Olson;J. Crawford;A. Fried;L. Huey;R. Cohen;B. Heikes;H. Singh
OH反应性的测量，OH寿命的倒数，提供了一个强有力的工具，研究大气光化学。在第二阶段的洲际化学传输实验-B（INTEX-B）活动中，NASA DC-8飞机上首次设计和部署了一个新的机载OH反应性仪器，该实验的重点是亚洲污染物在太平洋上空的流出，基地设在夏威夷和阿拉斯加。OH反应性通过将通过在可移动棒中用185 nm UV光光解水蒸气产生的OH添加到流管中的环境空气流中并用激光诱导荧光测量OH信号来测量。当棒从OH检测器拉回时，记录OH信号衰减; 1 ln（信号）/1时间的斜率为OH反应性。在2个置信水平下，低海拔地区的总绝对不确定度约为1 s ~ 1（衰减约为6s ~ 1），高海拔地区为0.7s ~ 1（衰减约为2s ~ 1）。从INTEX-B第二阶段中获得的中值垂直剖面来看，测得的OH反应性（4.0±1.0 s-1）高于
The measurement of OH reactivity, the inverse of the OH lifetime, provides a powerful tool to investigate atmospheric photochemistry. A new airborne OH reactivity instrument was designed and deployed for the first time on the NASA DC-8 aircraft during the second phase of Inter- continental Chemical Transport Experiment-B (INTEX-B) campaign, which was focused on the Asian pollution out- flow over Pacific Ocean and was based in Hawaii and Alaska. The OH reactivity was measured by adding OH, generated by photolyzing water vapor with 185 nm UV light in a moveable wand, to the flow of ambient air in a flow tube and mea- suring the OH signal with laser induced fluorescence. As the wand was pulled back away from the OH detector, the OH signal decay was recorded; the slope of 1ln(signal)/1 time was the OH reactivity. The overall absolute uncer- tainty at the 2 confidence levels is about 1 s 1 at low al- titudes (for decay about 6 s 1 ), and 0.7 s 1 at high altitudes (for decay about 2 s 1 ). From the median vertical profile obtained in the second phase of INTEX-B, the measured OH reactivity (4.0±1.0 s 1 ) is higher than the OH reactiv-