Measurement of HO2NO2 in the free troposphere during the Intercontinental Chemical Transport Experiment–North America 2004
Measurement of HO2NO2 in the free troposphere during the Intercontinental Chemical Transport Experiment–North America 2004
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2004 年北美洲际化学品运输实验期间自由对流层中 HO2NO2 的测量
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
I. Sokolik
中科院分区：
文献类型：
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作者：
S. Kim;L. Huey;R. Stickel;D. Tanner;J. Crawford;J. Olson;Guojun Chen;W. Brune;X. Ren;R. Lesher;P. Wooldridge;T. Bertram;A. Perring;R. Cohen;B. Lefer;R. Shetter;M. Avery;G. Diskin;I. Sokolik
[1]在2004年北美洲际化学传输实验期间，NASA DC-8利用化学电离质谱仪（CIMS）对对流层上层的HO 2NO 2进行了首次直接原位测量。由于HO 2NO 2对HOx和NOx的双重依赖性，这些测量提供了自由对流层中HOx化学的独立诊断，并补充了HOx的直接观测。平均而言，最高的HO 2NO 2混合比为76 pptv（中位数= 77 pptv，σ = 39 pptv），在8-9公里的高度观察。HO 2NO 2的简单稳态计算，受HOx，NOx和J值的测量的约束，与对流层中部的测量结果吻合良好（斜率= 0.90，R2 = 0.60，z = 5.5-7.5 km），其中热分解是主要的损失过程。在8 km以上，计算的稳态HO 2NO 2与观测值（R2 = 0.20）的一致性较差，并且通常大2.4倍。相反，使用模型导出的HOx的稳态计算显示出与对流层中部（斜率= 0.96，截距= 7.0，R2 = 0.63）和对流层上部（斜率= 0.80，截距= 32.2，R2 = 0.58）观测到的HO 2NO 2合理的一致性。这些结果表明，观测到的HO 2和HO 2NO 2是在对流层上层的协议差，但HO 2NO 2水平是符合目前的光化学理论。
[1] The first direct in situ measurements of HO2NO2 in the upper troposphere were performed from the NASA DC-8 during the Intercontinental Chemical Transport Experiment–North America 2004 with a chemical ionization mass spectrometer (CIMS). These measurements provide an independent diagnostic of HOx chemistry in the free troposphere and complement direct observations of HOx, because of the dual dependency of HO2NO2 on HOx and NOx. On average, the highest HO2NO2 mixing ratio of 76 pptv (median = 77 pptv, σ = 39 pptv) was observed at altitudes of 8–9 km. Simple steady state calculations of HO2NO2, constrained by measurements of HOx, NOx, and J values, are in good agreement (slope = 0.90, R2 = 0.60, and z = 5.5–7.5 km) with measurements in the midtroposphere where thermal decomposition is the major loss process. Above 8 km the calculated steady state HO2NO2 is in poor agreement with observed values (R2 = 0.20) and is typically larger by a factor of 2.4. Conversely, steady state calculations using model-derived HOx show reasonable agreement with the observed HO2NO2 in both the midtroposphere (slope = 0.96, intercept = 7.0, and R2 = 0.63) and upper troposphere (slope = 0.80, intercept = 32.2, and R2 = 0.58). These results indicate that observed HO2 and HO2NO2 are in poor agreement in the upper troposphere but that HO2NO2 levels are consistent with current photochemical theory.