Photochemistry of formaldehyde during the 1993 Tropospheric OH Photochemistry Experiment

Fried, Alan; McKeen, S. A.; Sewell, Scott; Harder, J. W.; Henry, Bruce; Goldan, P. D.; Kuster, W. C.; Williams, E. J.; Baumann, Karsten; Shetter, R. E.; Cantrell, C. A.

doi:10.1029/96jd03249

Cited by 62 publications

(35 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The CH 3 O 2 recombination reactions contribute 28%, and the two degradation channels of CH 3 O 2 H comprise a further 36% of the CH 2 O production. In contrast to the continental boundary layer, where the CH 4 degradation is dominated by the CH 3 O 2 + NO channel [ Fried et al , 1997], in the remote MBL the flux through the CH 3 O 2 recombination route and the two CH 3 O 2 H routes are of similar magnitude.…”

Section: Resultsmentioning

confidence: 99%

Are CH₂O measurements in the marine boundary layer suitable for testing the current understanding of CH₄ photooxidation?: A model study

Wagner¹

2002

J.‐Geophys.‐Res.

View full text Add to dashboard Cite

[1] On the basis of a data set collected during the Indian Ocean Experiment (INDOEX) campaign 1999, we investigated the formaldehyde (CH 2 O) budget in the southern Indian Ocean (SIO). With a photochemical box model we simulated the contribution of methane and nonmethane volatile organic compounds to the CH 2 O budget. To identify the reactions and model constraints that introduce the largest uncertainties in the modeled CH 2 O concentration, we carried out a local sensitivity analysis. Furthermore, a Monte Carlo method was used to assess the global error of the model predictions. According to this analysis the 2s uncertainty in the modeled CH 2 O concentration is 49%. The deviation between observed (200 ± 70 parts per trillion by volume (pptv) (2s)) and modeled (224 ± 110 pptv (2s)) daily mean CH 2 O concentration is 12%. However, the combined errors of model and measurement are such that deviations as large as 65% are not significant at the 2s level. Beyond the ''standard'' photochemistry we analyzed the impact of halogen and aerosol chemistry on the CH 2 O concentration and investigated the vertical distribution of CH 2 O in the marine boundary layer (MBL). Calculations with the Model of Chemistry Considering Aerosols indicate that, based on the current understanding, halogen chemistry and aerosol chemistry have no significant impact on the CH 2 O concentration under conditions encountered in the SIO. However, a detailed investigation including meteorological effects such as precipitation scavenging and convection reveals an uncertainty in state-of-the-art model predictions for CH 2 O in the MBL that is too large for a meaningful test of the current understanding of CH 4 photooxidation.

show abstract

Section: Resultsmentioning

confidence: 99%

Are CH₂O measurements in the marine boundary layer suitable for testing the current understanding of CH₄ photooxidation?: A model study

Wagner¹

2002

J.‐Geophys.‐Res.

View full text Add to dashboard Cite

show abstract

“…This gas, which is one of the most abundant gas phase carbonyl compounds found in the atmosphere, is formed by the oxidation of most anthropogenic and biogenic hydrocarbons initiated by reactions with the hydroxyl (OH) radical and ozone (O 3 ). Over continental areas, oxidation of nonmethane hydrocarbons (NMHCs) dominates the production of CH 2 O [ Fried et al , 1997b]. This gas is emitted directly by incomplete fossil fuel combustion as well as from secondary processes [ de Serves , 1994; Sigsby et al , 1987].…”

Section: Introductionmentioning

confidence: 99%

“… In the lower atmosphere, the radical products HCO and H generate the hydroperoxy radical HO2 via and : The radical photolysis channel followed by and is a net source of odd hydrogen radicals, HO x , (HO x = HO 2 + OH + H) in the atmosphere. This radical channel plays a larger role in HO x production for high solar zenith angles [ Fried et al , 1997b] and in the mid to upper troposphere where radical production from O( 1 D) with H 2 O diminishes as the available H 2 O vapor decreases with altitude [ Wennberg et al , 1998].…”

Section: Introductionmentioning

confidence: 99%

Airborne tunable diode laser measurements of formaldehyde during TRACE‐P: Distributions and box model comparisons

et al. 2003

Self Cite

View full text Add to dashboard Cite

[1] Airborne measurements of CH 2 O were acquired employing tunable diode laser absorption spectroscopy during the 2001 Transport and Chemical Evolution Over the Pacific (TRACE-P) study onboard NASA's DC-8 aircraft. Above $2.5 km, away from the most extreme pollution influences and heavy aerosol loadings, comprehensive comparisons with a steady state box model revealed agreement to within ±37 pptv in the measurement and model medians binned according to altitude and longitude. Likewise, a near unity slope (0.98 ± 0.03) was obtained from a bivariate fit of the measurements, averaged into 25 pptv model bins, versus the modeled concentrations for values up to $450 pptv. Both observations suggest that there are no systematic biases on average between CH 2 O measurements and box model results out to model values $450 pptv. However, the model results progressively underpredict the observations at higher concentrations, possibly due to transport effects unaccounted for in the steady state model approach. The assumption of steady state also appears to contribute to the scatter observed in the point-by-point comparisons. The measurement-model variance was further studied employing horizontal flight legs. For background legs screened using a variety of nonmethane hydrocarbon (NMHC) tracers, measurement and model variance agreed to within 15%. By contrast, measurement variance was $60% to 80% higher than the model variance, even with small to modest elevations in the NMHC tracers. Measurement-model comparisons of CH 2 O in clouds and in the lower marine troposphere in the presence of marine aerosols suggest rather significant CH 2 O uptake by as much as 85% in one extreme case compared to expectations based on modeled gas phase processes.

show abstract

“…To fully appreciate the complexity of an actual instrument designed for field applications, it is helpful to consult Fried et al, (45,121) and Nelson et al (120) …”

Section: Tunable Mid-infrared Diode Laser Absorption Spectrometermentioning

confidence: 99%

“…detection of formaldehyde. (45) A more subtle problem with lead-salt diode lasers has to do with thermal cycling, a process in which a laser is simply warmed up to room temperature and then cooled back to its normal operating temperature. The simple process tends to cause irreversible changes in prior laser-tuning characteristics and emission wavelength.…”

Section: Fundamental Band Detection With Mid-infrared Lasersmentioning

confidence: 99%

Diode Laser Spectroscopic Monitoring of Trace Gases

Tittel¹,

Петров²

2000

Encyclopedia of Analytical Chemistry

View full text Add to dashboard Cite

Modern diode laser spectroscopy is becoming an important and a more widely used tool for detection and measurement of trace gases. The change is driven by the recent advances in diode laser technology and diode laser frequency conversion techniques, which now push the limits of emission wavelength, output power, operating temperature, miniaturization, and cost. Basic features of the diode laser now find new, interesting, and unique use in well‐established laboratory and field applications related to trace‐gas detection, and in some instances even transform the traditional spectroscopic methods. It is the purpose of this chapter to familiarize the reader with the key elements of diode laser technology and analytical methods used in diode laser spectroscopy.

show abstract

Photochemistry of formaldehyde during the 1993 Tropospheric OH Photochemistry Experiment

Cited by 62 publications

References 48 publications

Are CH₂O measurements in the marine boundary layer suitable for testing the current understanding of CH₄ photooxidation?: A model study

Are CH₂O measurements in the marine boundary layer suitable for testing the current understanding of CH₄ photooxidation?: A model study

Airborne tunable diode laser measurements of formaldehyde during TRACE‐P: Distributions and box model comparisons

Diode Laser Spectroscopic Monitoring of Trace Gases

Contact Info

Product

Resources

About

Photochemistry of formaldehyde during the 1993 Tropospheric OH Photochemistry Experiment

Cited by 62 publications

References 48 publications

Are CH2O measurements in the marine boundary layer suitable for testing the current understanding of CH4 photooxidation?: A model study

Are CH2O measurements in the marine boundary layer suitable for testing the current understanding of CH4 photooxidation?: A model study

Airborne tunable diode laser measurements of formaldehyde during TRACE‐P: Distributions and box model comparisons

Diode Laser Spectroscopic Monitoring of Trace Gases

Contact Info

Product

Resources

About

Are CH₂O measurements in the marine boundary layer suitable for testing the current understanding of CH₄ photooxidation?: A model study

Are CH₂O measurements in the marine boundary layer suitable for testing the current understanding of CH₄ photooxidation?: A model study