The role of BrNO<sub>3</sub> in marine tropospheric chemistry: A model study

Sander, R.; Rudich, Yinon; Glasow, R. von; Crutzen, Paul J.

doi:10.1029/1999gl900478

Cited by 98 publications

(90 citation statements)

References 22 publications

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“…In this regard, our Δ 17 O(NO 3 − ) measurements are incompatible with a high production rate of HNO 3 from N 2 O 5 hydrolysis, in agreement with studies that have suggested a substantially reduced magnitude of the NO x sink from N 2 O 5 for clean environments (5,33,38). It is possible that for the remote marine atmosphere, the lack of halogen chemistry implementation in models has led to an overestimation of the N 2 O 5 pathway (39). Because oxidation chemistry in the atmosphere involves a transfer of oxygen atoms, stable oxygen isotope ratios are particularly useful tools for following such chemistry, as demonstrated in the present work.…”

Section: Discussionmentioning

confidence: 38%

Isotopic composition of atmospheric nitrate in a tropical marine boundary layer

Savarino

Morin

Erbland

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Long-term observations of the reactive chemical composition of the tropical marine boundary layer (MBL) are rare, despite its crucial role for the chemical stability of the atmosphere. Recent observations of reactive bromine species in the tropical MBL showed unexpectedly high levels that could potentially have an impact on the ozone budget. Uncertainties in the ozone budget are amplified by our poor understanding of the fate of NO x (= NO + NO 2 ), particularly the importance of nighttime chemical NO x sinks. Here, we present year-round observations of the multiisotopic composition of atmospheric nitrate in the tropical MBL at the Cape Verde Atmospheric Observatory. We show that the observed oxygen isotope ratios of nitrate are compatible with nitrate formation chemistry, which includes the BrNO 3 sink at a level of ca. 20 ± 10% of nitrate formation pathways. The results also suggest that the N 2 O 5 pathway is a negligible NO x sink in this environment. Observations further indicate a possible link between the NO 2 /NO x ratio and the nitrogen isotopic content of nitrate in this low NO x environment, possibly reflecting the seasonal change in the photochemical equilibrium among NO x species. This study demonstrates the relevance of using the stable isotopes of oxygen and nitrogen of atmospheric nitrate in association with concentration measurements to identify and constrain chemical processes occurring in the MBL.monitoring | oxidation | tropic | bromine chemistry | aerosols T he tropical marine lower troposphere is one of the most photochemically active compartments of the global atmosphere. The year-round high solar radiation, temperature, and humidity render this region the second largest contributor to methane removal via the OH sink (1). A large proportion of tropospheric ozone loss also occurs in the tropical marine boundary layer (MBL), where the concentrations of precursors, such as NO x (= NO + NO 2 ) and volatile organic carbons (VOCs) (2), are generally too low to keep the ozone production rate above its destruction rate. The destruction of ozone is further highlighted by the recently discovered role of halogen chemistry at low latitudes (3), which is known to destroy ozone catalytically (4). The subtle oxidation chemistry coupling NO x , halogens, and VOCs with ozone production and destruction in the MBL is still not fully understood, as demonstrated by the historically overlooked bromine chemistry (3) or the role of heterogeneous N 2 O 5 hydrolysis as a NO x sink (5, 6).Being the end product of the NO x /O 3 /VOC interaction, atmospheric nitrate is particularly well suited to probe such chemistry, especially through its stable isotope composition (7). Indeed, isotopic measurements have proven to be instrumental in identifying and quantifying sources, processes affecting the formation of atmospheric nitrate [particulate NO 3 − plus gas-phase nitric acid (HNO 3 ); hereafter defined as NO 3 − ], and the role of its precursors (i.e., the complex chemical interactions between NO x , halogens, and ozone...

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Section: Discussionmentioning

confidence: 38%

Isotopic composition of atmospheric nitrate in a tropical marine boundary layer

Savarino

Morin

Erbland

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…The contribution of BrNO 3 to NO y is less than 0.5%. The heterogenous reaction of BrNO 3 produces particulate NO − 3 (see Sander et al (1999)) and therefore contributes to the loss of NO x . This NO x loss by the heterogeneous reaction of BrNO 3 is about 4.5 and 10% of the NO x loss by reaction NO 2 + OH−→HNO 3 in the runs "high lat" and "tropics", respectively.…”

Section: Effect On Nitrogen Oxidesmentioning

confidence: 99%

“…based on detailed reaction cycles (Fan and Jacob, 1992;Abbatt, 1994;Vogt et al, 1996;Sander et al, 1999;Fickert et al, 1999). In the current model version no aqueous phase species are considered, therefore we listed only the gas phase products, other products are assumed to be taken up irreversibly by the aerosol.…”

Section: Model Description and Source Scenariosmentioning

confidence: 99%

Impact of reactive bromine chemistry in the troposphere

et al. 2004

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Abstract.Recently several field campaigns and satellite observations have found strong indications for the presence of bromine oxide (BrO) in the free troposphere. Using a global atmospheric chemistry transport model we show that BrO mixing ratios of a few tenths to 2 pmol mol −1 lead to a reduction in the zonal mean O 3 mixing ratio of up to 18% in widespread areas and regionally up to 40% compared to a model run without bromine chemistry. A lower limit approach for the marine boundary layer, that does not explicitly include the release of halogens from sea salt aerosol, shows that for dimethyl sulfide (DMS) the effect is even larger, with up to 60% reduction of its tropospheric column. This is accompanied by dramatic changes in DMS oxidation pathways, reducing its cooling effect on climate. In addition there are changes in the HO 2 : OH ratio that also affect NO x and PAN. These results imply that potentially significant strong sinks for O 3 and DMS have so far been ignored in many studies of the chemistry of the troposphere.

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“…In the marine boundary layer, inorganic bromine (Br) and iodine (I), which are involved in free radical chemistry, originate in part from their organic counterparts and influence tropospheric oxidation capacity via a number of reaction cycles. These include catalytic ozone (O 3 ) destruction (Read et al, 2008); modification of NO x (Sander et al, 1999;Pszenny et al, 2004) and HO x (Stutz et al, 1999;Bloss et al, 2005;Sommariva et al, 2006) cycles with resulting effects on lifetimes of other climatically important trace gases; oxidation of DMS (von Glasow et al, 2004); and oxidation of S(IV) in acidified sea salt aerosol and cloud droplets (Vogt et al, 1996). In the lower stratosphere, Br dramatically accelerates the chlorine-driven depletion of ozone.…”

Section: Introductionmentioning

confidence: 99%

Technical Note: Ensuring consistent, global measurements of very short-lived halocarbon gases in the ocean and atmosphere

et al. 2010

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Abstract. Very short-lived halocarbons are significant sources of reactive halogen in the marine boundary layer, and likely in the upper troposphere and lower stratosphere. Quantifying ambient concentrations in the surface ocean and atmosphere is essential for understanding the atmospheric impact of these trace gas fluxes. Despite the body of literature increasing substantially over recent years, calibration issues complicate the comparison of results and limit the utility of building larger-scale databases that would enable further development of the science (e.g. sea-air flux quantification, model validation, etc.). With this in mind, thirtyone scientists from both atmospheric and oceanic halocarbon communities in eight nations gathered in London in February 2008 to discuss the scientific issues and plan an international effort toward developing common calibration scales (http://tinyurl.com/c9cg58). Here, we discuss the outputs from this meeting, suggest the compounds that should be targeted initially, identify opportunities for beginning calibration and comparison efforts, and make recommendations for ways to improve the comparability of previous and future measurements.

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The role of BrNO₃ in marine tropospheric chemistry: A model study

Cited by 98 publications

References 22 publications

Isotopic composition of atmospheric nitrate in a tropical marine boundary layer

Isotopic composition of atmospheric nitrate in a tropical marine boundary layer

Impact of reactive bromine chemistry in the troposphere

Technical Note: Ensuring consistent, global measurements of very short-lived halocarbon gases in the ocean and atmosphere

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The role of BrNO3 in marine tropospheric chemistry: A model study

Cited by 98 publications

References 22 publications

Isotopic composition of atmospheric nitrate in a tropical marine boundary layer

Isotopic composition of atmospheric nitrate in a tropical marine boundary layer

Impact of reactive bromine chemistry in the troposphere

Technical Note: Ensuring consistent, global measurements of very short-lived halocarbon gases in the ocean and atmosphere

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The role of BrNO₃ in marine tropospheric chemistry: A model study