An investigation of South Pole HOx chemistry: Comparison of model results with ISCAT observations

Chen, G.; Davis, Douglas D.; Crawford, J. H.; Nowak, John B.; Eisele, F.; Mauldin, R. L.; Tanner, David J.; Buhr, M.; Shetter, R. E.; Lefer, B. L.; Arimoto, R.; Hogan, Austin W.; Blake, Donald R.

doi:10.1029/2001gl013158

Cited by 61 publications

(49 citation statements)

References 15 publications

(5 reference statements)

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“…Model runs without HONO were run 24 h a day excluding periods of missing radical or precursor data. A simpler model utilizing explicit HO x -NO x -CH 4 (30 reactions) similar to the mechanism described in Chen et al (2001) was used to check the contribution of NMHC. Predicted number densities of hydroxyl radicals were $8% lower when the NMHC model was used while predicted peroxy number densities were 3% higher.…”

Section: Article In Pressmentioning

confidence: 99%

Observations of hydroxyl and the sum of peroxy radicals at Summit, Greenland during summer 2003

Sjostedt

Huey

Tanner

et al. 2007

Atmospheric Environment

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The first measurements of peroxy (HO 2 +RO 2 ) and hydroxyl (OH) radicals above the arctic snowpack were collected during the summer 2003 campaign at Summit, Greenland. The median measured number densities for peroxy and hydroxyl radicals were 2.2 Â 10 8 mol cm À3 and 6.4 Â 10 6 mol cm À3, respectively. The observed peroxy radical values are in excellent agreement (R 2 ¼ 0:83, M=O ¼ 1:06) with highly constrained model predictions. However, calculated hydroxyl number densities are consistently more than a factor of 2 lower than the observed values. These results indicate that our current understanding of radical sources and sinks is in accord with our observations in this environment but that there may be a mechanism that is perturbing the (HO 2 +RO 2 )/OH ratio. This observed ratio was also found to depend on meteorological conditions especially during periods of high winds accompanied by blowing snow. Backward transport model simulations indicate that these periods of high winds were characterized by rapid transport (1-2 days) of marine boundary layer air to Summit. These data suggest that the boundary layer photochemistry at Summit may be periodically impacted by halogens. r

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Section: Article In Pressmentioning

confidence: 99%

Observations of hydroxyl and the sum of peroxy radicals at Summit, Greenland during summer 2003

Sjostedt

Huey

Tanner

et al. 2007

Atmospheric Environment

Self Cite

110

130

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“…Chen et al (2001) and showed that the presence of high concentrations of NO x produced by the photolysis of nitrate present in surface snow permits the required efficient recycling of HO 2 into OH. Aside from snow photochemical emission of NO x that acts as a secondary source of OH, the role of atmospheric nitrous acid (HONO) as a primary source of OH remains unclear.…”

Section: Introductionmentioning

confidence: 99%

Large mixing ratios of atmospheric nitrous acid (HONO) at Concordia (East Antarctic Plateau) in summer: a strong source from surface snow?

et al. 2014

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Abstract. During the austral summer 2011/2012 atmospheric nitrous acid (HONO) was investigated for the second time at the Concordia site (75 • 06 S, 123 • 33 E), located on the East Antarctic Plateau, by deploying a long-path absorption photometer (LOPAP). Hourly mixing ratios of HONO measured in December 2011/January 2012 (35 ± 5.0 pptv) were similar to those measured in December 2010/January 2011 (30.4 ± 3.5 pptv). The large value of the HONO mixing ratio at the remote Concordia site suggests a local source of HONO in addition to weak production from oxidation of NO by the OH radical. Laboratory experiments demonstrate that surface snow removed from Concordia can produce gasphase HONO at mixing ratios half that of the NO x mixing ratio produced in the same experiment at typical temperatures encountered at Concordia in summer. Using these lab data and the emission flux of NO x from snow estimated from the vertical gradient of atmospheric concentrations measured during the campaign, a mean diurnal HONO snow emission ranging between 0.5 and 0.8 × 10 9 molecules cm −2 s −1 is calculated. Model calculations indicate that, in addition to around 1.2 pptv of HONO produced by the NO oxidation, these HONO snow emissions can only explain 6.5 to 10.5 pptv of HONO in the atmosphere at Concordia. To explain the difference between observed and simulated HONO mixing ratios, tests were done both in the field and at lab to explore the possibility that the presence of HNO 4 had biased the measurements of HONO.

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“…Their primary relevance is that they act as reservoir species for HO x and NO x , which are now recognised to drive the surprisingly vigorous oxidation chemistry that has been observed during Antarctic summer (e.g. Davis et al, 2001;Chen et al, 2001). The spatial and temporal distribution of HO 2 NO 2 and HNO 3 across the polar regions thus becomes important for understanding the overall atmospheric chemical system, and models require details of their sources, and any physical exchange process by which they move from one environmental compartment to another.…”

Section: Introductionmentioning

confidence: 99%

HO2NO2 and HNO3 in the coastal Antarctic winter night: a "lab-in-the-field" experiment

et al. 2014

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Abstract.Observations of peroxynitric acid (HO 2 NO 2 ) and nitric acid (HNO 3 ) were made during a 4 month period of Antarctic winter darkness at the coastal Antarctic research station, Halley. Mixing ratios of HNO 3 ranged from instrumental detection limits to ∼ 8 parts per trillion by volume (pptv), and of HO 2 NO 2 from detection limits to ∼ 5 pptv; the average ratio of HNO 3 : HO 2 NO 2 was 2.0(± 0.6) : 1, with HNO 3 always present at greater mixing ratios than HO 2 NO 2 during the winter darkness. An extremely strong association existed for the entire measurement period between mixing ratios of the respective trace gases and temperature: for HO 2 NO 2 , R 2 = 0.72, and for HNO 3 , R 2 = 0.70. We focus on three cases with considerable variation in temperature, where wind speeds were low and constant, such that, with the lack of photochemistry, changes in mixing ratio were likely to be driven by physical mechanisms alone. We derived enthalpies of adsorption ( H ads ) for these three cases. The average H ads for HNO 3 was −42 ± 2 kJ mol −1 and for HO 2 NO 2 was −56 ± 1 kJ mol −1 ; these values are extremely close to those derived in laboratory studies. This exercise demonstrates (i) that adsorption to/desorption from the snow pack should be taken into account when addressing budgets of boundary layer HO 2 NO 2 and HNO 3 at any snow-covered site, and (ii) that Antarctic winter can be used as a natural "laboratory in the field" for testing data on physical exchange mechanisms.

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An investigation of South Pole HO_x chemistry: Comparison of model results with ISCAT observations

Cited by 61 publications

References 15 publications

Observations of hydroxyl and the sum of peroxy radicals at Summit, Greenland during summer 2003

Observations of hydroxyl and the sum of peroxy radicals at Summit, Greenland during summer 2003

Large mixing ratios of atmospheric nitrous acid (HONO) at Concordia (East Antarctic Plateau) in summer: a strong source from surface snow?

HO<sub>2</sub>NO<sub>2</sub> and HNO<sub>3</sub> in the coastal Antarctic winter night: a "lab-in-the-field" experiment

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An investigation of South Pole HOx chemistry: Comparison of model results with ISCAT observations

Cited by 61 publications

References 15 publications

Observations of hydroxyl and the sum of peroxy radicals at Summit, Greenland during summer 2003

Observations of hydroxyl and the sum of peroxy radicals at Summit, Greenland during summer 2003

Large mixing ratios of atmospheric nitrous acid (HONO) at Concordia (East Antarctic Plateau) in summer: a strong source from surface snow?

HO&lt;sub&gt;2&lt;/sub&gt;NO&lt;sub&gt;2&lt;/sub&gt; and HNO&lt;sub&gt;3&lt;/sub&gt; in the coastal Antarctic winter night: a &quot;lab-in-the-field&quot; experiment

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An investigation of South Pole HO_x chemistry: Comparison of model results with ISCAT observations

HO<sub>2</sub>NO<sub>2</sub> and HNO<sub>3</sub> in the coastal Antarctic winter night: a "lab-in-the-field" experiment