HO<sub><i>x</i></sub> chemistry during INTEX‐A 2004: Observation, model calculation, and comparison with previous studies
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- Xinrong Ren
- Department of Meteorology Pennsylvania State University University Park Pennsylvania USA
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- Jennifer R. Olson
- Science Directorate NASA Langley Research Center Hampton Virginia USA
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- James H. Crawford
- Science Directorate NASA Langley Research Center Hampton Virginia USA
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- William H. Brune
- Department of Meteorology Pennsylvania State University University Park Pennsylvania USA
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- Jingqiu Mao
- Department of Meteorology Pennsylvania State University University Park Pennsylvania USA
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- Robert B. Long
- Department of Meteorology Pennsylvania State University University Park Pennsylvania USA
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- Zhong Chen
- Department of Meteorology Pennsylvania State University University Park Pennsylvania USA
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- Gao Chen
- Science Directorate NASA Langley Research Center Hampton Virginia USA
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- Melody A. Avery
- Science Directorate NASA Langley Research Center Hampton Virginia USA
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- Glen W. Sachse
- Science Directorate NASA Langley Research Center Hampton Virginia USA
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- John D. Barrick
- Science Directorate NASA Langley Research Center Hampton Virginia USA
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- Glenn S. Diskin
- Science Directorate NASA Langley Research Center Hampton Virginia USA
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- L. Greg Huey
- School of Earth and Atmospheric Sciences Georgia Institute of Technology Atlanta Georgia USA
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- Alan Fried
- Earth Observing Laboratory National Center for Atmospheric Research Boulder Colorado USA
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- Ronald C. Cohen
- Department of Chemistry and Department of Earth and Planetary Science University of California Berkeley California USA
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- Brian Heikes
- Graduate School of Oceanography University of Rhode Island Narragansett Rhode Island USA
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- Paul O. Wennberg
- Division of Engineering and Applied Sciences California Institute of Technology Pasadena California USA
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- Hanwant B. Singh
- NASA Ames Research Center Moffett Field California USA
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- Donald R. Blake
- Department of Chemistry University of California Irvine California USA
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- Richard E. Shetter
- National Suborbital Education and Research Center University of North Dakota Grand Forks North Dakota USA
Description
<jats:p>OH and HO<jats:sub>2</jats:sub> were measured with the Airborne Tropospheric Hydrogen Oxides Sensor (ATHOS) as part of a large measurement suite from the NASA DC‐8 aircraft during the Intercontinental Chemical Transport Experiment‐A (INTEX‐A). This mission, which was conducted mainly over North America and the western Atlantic Ocean in summer 2004, was an excellent test of atmospheric oxidation chemistry. The HOx results from INTEX‐A are compared to those from previous campaigns and to results for other related measurements from INTEX‐A. Throughout the troposphere, observed OH was generally 0.95 of modeled OH; below 8 km, observed HO<jats:sub>2</jats:sub> was generally 1.20 of modeled HO<jats:sub>2</jats:sub>. This observed‐to‐modeled comparison is similar to that for TRACE‐P, another midlatitude study for which the median observed‐to‐modeled ratio was 1.08 for OH and 1.34 for HO<jats:sub>2</jats:sub>, and to that for PEM‐TB, a tropical study for which the median observed‐to‐modeled ratio was 1.17 for OH and 0.97 for HO<jats:sub>2</jats:sub>. HO<jats:sub>2</jats:sub> behavior above 8 km was markedly different. The observed‐to‐modeled HO<jats:sub>2</jats:sub> ratio increased from ∼1.2 at 8 km to ∼3 at 11 km with the observed‐to‐modeled ratio correlating with NO. Above 8 km, the observed‐to‐modeled HO<jats:sub>2</jats:sub> and observed NO were both considerably greater than observations from previous campaigns. In addition, the observed‐to‐modeled HO<jats:sub>2</jats:sub>/OH, which is sensitive to cycling reactions between OH and HO<jats:sub>2</jats:sub>, increased from ∼1.5 at 8 km to almost 3.5 at 11 km. These discrepancies suggest a large unknown HO<jats:sub><jats:italic>x</jats:italic></jats:sub> source and additional reactants that cycle HO<jats:sub><jats:italic>x</jats:italic></jats:sub> from OH to HO<jats:sub>2</jats:sub>. In the continental planetary boundary layer, the observed‐to‐modeled OH ratio increased from 1 when isoprene was less than 0.1 ppbv to over 4 when isoprene was greater than 2 ppbv, suggesting that forests throughout the United States are emitting unknown HO<jats:sub><jats:italic>x</jats:italic></jats:sub> sources. Progress in resolving these discrepancies requires a focused research activity devoted to further examination of possible unknown OH sinks and HO<jats:sub><jats:italic>x</jats:italic></jats:sub> sources.</jats:p>
Journal
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- Journal of Geophysical Research: Atmospheres
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Journal of Geophysical Research: Atmospheres 113 (D5), D05310-, 2008-03-08
American Geophysical Union (AGU)
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Details 詳細情報について
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- CRID
- 1362544420090285568
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- ISSN
- 01480227
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- Data Source
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- Crossref