Observations of hydroxyl and peroxy radicals and the impact of BrO at Summit, Greenland in 2007 and 2008

Liao, J.; Huey, L. G.; Tanner, David J.; Brough, N.; Brooks, Steve; Dibb, Jack E.; Stutz, J.; Thomas, Jennie L.; Lefer, B. L.; Haman, C.; Gorham, K.

doi:10.5194/acp-11-8577-2011

Cited by 43 publications

(62 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, concurrent measurements of surface ozone and local meteorology were made. Although such observations have been made in the Arctic (Neuman et al, 2010;Liao et al, 2011aLiao et al, , b, 2012b, this is the first such suite of measurements made in Antarctica.…”

Section: Z Buys Et Al: High Temporal Resolution Br 2 Brcl and Bromentioning

confidence: 99%

“…The filter tube contained activated coarse charcoal and nylon glass wool that had been previously soaked and dried in a concentrated NaHCO 3 solution. A similar scrubbing method had previously been successfully employed Liao et al, 2011a).…”

Section: Cims Instrument Descriptionmentioning

confidence: 99%

“…The ratio of the rate constants for reaction SO 2 + SF BrO calibration was achieved using a similar method to that described in Sect. 2.2 in Liao et al (2011a). We use the ratio of the rate constant for the reaction Br 2 + SF − 6 → Br − 2 + SF 6 to the reaction BrO + SF − 6 → BrO − + SF 6 (determined to be 1.0 ± 25 % in the laboratory by Liao et al, 2011a), along with the dew point calculation, to determine the BrO calibration.…”

Section: Cims Instrument Descriptionmentioning

confidence: 99%

See 2 more Smart Citations

High temporal resolution Br2, BrCl and BrO observations in coastal Antarctica

et al. 2013

Self Cite

View full text Add to dashboard Cite

Abstract. There are few observations of speciated inorganic bromine in polar regions against which to test current theory. Here we report the first high temporal resolution measurements of Br2, BrCl and BrO in coastal Antarctica, made at Halley during spring 2007 using a Chemical Ionisation Mass Spectrometer (CIMS). We find indications for an artefact in daytime BrCl measurements arising from conversion of HOBr, similar to that already identified for observations of Br2 made using a similar CIMS method. Using the MISTRA model, we estimate that the artefact represents a conversion of HOBr to Br2 of the order of several tens of percent, while that for HOBr to BrCl is less but non-negligible. If the artefact is indeed due to HOBr conversion, then nighttime observations were unaffected. It also appears that all daytime BrO observations were artefact-free. Mixing ratios of BrO, Br2 and BrCl ranged from instrumental detection limits to 13 pptv (daytime), 45 pptv (nighttime), and 6 pptv (nighttime), respectively. We see considerable variability in the Br2 and BrCl observations over the measurement period which is strongly linked to the prevailing meteorology, and thus air mass origin. Higher mixing ratios of these species were generally observed when air had passed over the sea-ice zone prior to arrival at Halley, than from over the continent. Variation in the diurnal structure of BrO is linked to previous model work where differences in the photolysis spectra of Br2 and O3 is suggested to lead to a BrO maximum at sunrise and sunset, rather than a noon-time maxima. This suite of Antarctic data provides the first analogue to similar measurements made in the Arctic, and of note is that our maximum measured BrCl (nighttime) is less than half of the maximum measured during a similar period (spring-time) in the Arctic (also nighttime). This difference in maximum measured BrCl may also be the cause of a difference in the Br2 : BrCl ratio between the Arctic and Antarctic. An unusual event of trans-continental air mass transport appears to have been responsible for severe surface ozone depletion observed at Halley over a 2-day period. The halogen source region appears to be the Bellingshausen Sea, to the west of the Antarctic Peninsula, with the air mass having spent 3 1/2 days in complete darkness crossing the continent prior to arrival at Halley.

show abstract

Section: Z Buys Et Al: High Temporal Resolution Br 2 Brcl and Bromentioning

confidence: 99%

Section: Cims Instrument Descriptionmentioning

confidence: 99%

Section: Cims Instrument Descriptionmentioning

confidence: 99%

See 1 more Smart Citation

High temporal resolution Br2, BrCl and BrO observations in coastal Antarctica

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…Therefore the availability of this measurement allows an estimation of the instantaneous impact of bromine radicals on gas-phase chemistry without the requirement of including details of aqueous-phase processing and bromine activation in the model (e.g., see Liao et al, 2011). Model results including and then neglecting the measurements of BrO are compared to predict the instantaneous impact of bromine on the HO x budget and cycling in this high latitude environment.…”

Section: Impact Of Bro On Ho X During Arctic Springmentioning

confidence: 99%

An analysis of fast photochemistry over high northern latitudes during spring and summer using in-situ observations from ARCTAS and TOPSE

Olson

Brune

Mao³

et al. 2012

Atmos. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

Abstract.Observations of chemical constituents and meteorological quantities obtained during the two Arctic phases of the airborne campaign ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) are analyzed using an observationally constrained steady state box model. Measurements of OH and HO 2 from the Penn State ATHOS instrument are compared to model predictions. Forty percent of OH measurements below 2 km are at the limit of detection during the spring phase (ARCTAS-A). While the median observed-to-calculated ratio is near one, both the scatter of observations and the model uncertainty for OH are at the magnitude of ambient values. During the summer phase (ARCTAS-B), model predictions of OH are biased low relative to observations and demonstrate a high sensitivity to the level of uncertainty in NO observations. Predictions of HO 2 using observed CH 2 O and H 2 O 2 as model constraints are up to a factor of two larger than observed. A temperature-dependent terminal loss rate of HO 2 to aerosol recently proposed in the literature is shown to be insufficient to reconcile these differences. A comparison of ARCTAS-A to the high latitude springtime portion of the 2000 TOPSE campaign (Tropospheric Ozone Production about the Spring Equinox) shows similar meteorological and chemical environments with the exception of peroxides; observations of H 2 O 2 during ARCTAS-A were 2.5 to 3 times larger than those during TOPSE. The cause of this difference in peroxides remains unresolved and has important implications for the Arctic HO x budget. Unconstrained model predictions for both phases indicate photochemistry alone is unable to simultaneously sustain observed levels of CH 2 O and H 2 O 2 ; however when the model is constrained with observed CH 2 O, H 2 O 2 predictions from a range of Published by Copernicus Publications on behalf of the European Geosciences Union. J. R. Olson et al.: An analysis of fast photochemistry over high northern latitudesrainout parameterizations bracket its observations. A mechanism suitable to explain observed concentrations of CH 2 O is uncertain. Free tropospheric observations of acetaldehyde (CH 3 CHO) are 2-3 times larger than its predictions, though constraint of the model to those observations is sufficient to account for less than half of the deficit in predicted CH 2 O. The box model calculates gross O 3 formation during spring to maximize from 1-4 km at 0.8 ppbv d −1 , in agreement with estimates from TOPSE, and a gross production of 2-4 ppbv d −1 in the boundary layer and upper troposphere during summer. Use of the lower observed levels of HO 2 in place of model predictions decreases the gross production by 25-50 %. Net O 3 production is near zero throughout the ARCTAS-A troposphere, and is 1-2 ppbv in the boundary layer and upper altitudes during ARCTAS-B.

show abstract

“…by shifting the ratio [RO 2 ] / [OH] towards OH, like in the case of efficient halogen chemistry at Summit, Greenland (Liao et al, 2011), while biased measurements of NO x could affect the calculated radical losses and interconversion rates. Further speculations about possible impact of an unknown NO x regulating mechanism on the OH and RO 2 chemistry are not feasible at this stage.…”

Section: Photochemical Budget Of Radicalsmentioning

confidence: 99%

Measurements of OH and RO2 radicals at Dome C, East Antarctica

et al. 2014

View full text Add to dashboard Cite

Abstract. Concentrations of OH radicals and the sum of peroxy radicals, RO 2 , were measured in the boundary layer for the first time on the East Antarctic Plateau at the Concordia Station (Dome C, 75.10 • S, 123.31 • E) during the austral summer 2011/2012. The median concentrations of OH and RO 2 radicals were 3.1 × 10 6 molecule cm −3 and 9.9 × 10 7 molecule cm −3 , respectively. These values are comparable to those observed at the South Pole, confirming that the elevated oxidative capacity of the Antarctic atmospheric boundary layer found at the South Pole is not restricted to the South Pole but common over the high Antarctic plateau. At Concordia, the concentration of radicals showed distinct diurnal profiles with the median maximum of 5.2 × 10 6 molecule cm −3 at 11:00 and the median minimum of 1.1 × 10 6 molecule cm −3 at 01:00 for OH radicals and 1.7 × 10 8 molecule cm −3 and 2.5 × 10 7 molecule cm −3 for RO 2 radicals at 13:00 and 23:00, respectively (all times are local times). Concurrent measurements of O 3 , HONO, NO, NO 2 , HCHO and H 2 O 2 demonstrated that the major primary source of OH and RO 2 radicals at Dome C was the photolysis of HONO, HCHO and H 2 O 2 , with the photolysis of HONO contributing ∼ 75 % of total primary radical production. However, photochemical modelling with accounting for all these radical sources overestimates the concentrations of OH and RO 2 radicals by a factor of 2 compared to field observations. Neglecting the net OH production from HONO in the photochemical modelling results in an underestimation of the concentrations of OH and RO 2 radicals by a factor of 2. To explain the observations of radicals in this case an additional source of OH equivalent to about (25-35) % of measured photolysis of HONO is required. Even with a factor of 5 reduction in the concentrations of HONO, the photolysis of HONO represents the major primary radical source at Dome C. To account for a possibility of an overestimation of NO 2 observed at Dome C the calculations were also performed with NO 2 concentrations estimated by assuming steady-state NO 2 / NO ratios. In this case the net radical production from the photolysis of HONO should be reduced by a factor of 5 or completely removed based on the photochemical budget of OH or 0-D modelling, respectively. Another major factor leading to the large concentration of OH radicals measured at Dome C was large concentrations of NO molecules and fast recycling of peroxy radicals to OH radicals.

show abstract

Observations of hydroxyl and peroxy radicals and the impact of BrO at Summit, Greenland in 2007 and 2008

Cited by 43 publications

References 61 publications

High temporal resolution Br<sub>2</sub>, BrCl and BrO observations in coastal Antarctica

High temporal resolution Br<sub>2</sub>, BrCl and BrO observations in coastal Antarctica

An analysis of fast photochemistry over high northern latitudes during spring and summer using in-situ observations from ARCTAS and TOPSE

Measurements of OH and RO<sub>2</sub> radicals at Dome C, East Antarctica

Contact Info

Product

Resources

About

Observations of hydroxyl and peroxy radicals and the impact of BrO at Summit, Greenland in 2007 and 2008

Cited by 43 publications

References 61 publications

High temporal resolution Br&lt;sub&gt;2&lt;/sub&gt;, BrCl and BrO observations in coastal Antarctica

High temporal resolution Br&lt;sub&gt;2&lt;/sub&gt;, BrCl and BrO observations in coastal Antarctica

An analysis of fast photochemistry over high northern latitudes during spring and summer using in-situ observations from ARCTAS and TOPSE

Measurements of OH and RO&lt;sub&gt;2&lt;/sub&gt; radicals at Dome C, East Antarctica

Contact Info

Product

Resources

About

High temporal resolution Br<sub>2</sub>, BrCl and BrO observations in coastal Antarctica

High temporal resolution Br<sub>2</sub>, BrCl and BrO observations in coastal Antarctica

Measurements of OH and RO<sub>2</sub> radicals at Dome C, East Antarctica