Analysis of nitrate in the snow and atmosphere at Summit, Greenland: Chemistry and transport

Fibiger, D. L.; Dibb, Jack E.; Chen, Dexian; Thomas, Jennie L.; Burkhart, John F.; Huey, L. G.; Hastings, Meredith G.

doi:10.1002/2015jd024187

Cited by 29 publications

(59 citation statements)

References 94 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To further constrain NO 3 − oxidation pathways, we considered δ 18 O‐Δ 17 O relations for major tropospheric O bearing molecules incorporated into NO 3 − (Figure ; Fibiger et al, ; Michalski et al, ). Here we assume that the O isotopic composition of NO 3 − is derived from a mixture between a high δ 18 O‐Δ 17 O end‐member, O 3(terminal) and XO (δ 18 O = 95–115‰; Johnston & Thiemens, ), Δ 17 O =39.3±2.0‰ (Vicars & Savarino, ), and various low δ 18 O‐Δ 17 O end‐members including O 2 /RO 2 /HO 2 (δ 18 O = 23.5‰, Δ 17 O = 0‰; Kroopnick & Craig, ), H 2 O (δ 18 O = −27.5±20‰, Δ 17 O = 0‰) and OH (δ 18 O = ‐70±20‰, Δ 17 O = 0‰) (Michalski et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…We note that OH may not attain complete isotopic equilibrium with H 2 O vapor in polar regions because of low water mixing ratios (Morin et al, ). If OH maintains some of its O 3 character from O( 1 D), the mixing line between O 3 and OH remains the same, with the O atom incorporated into NO 3 − shifted toward O 3 (Fibiger et al, ). We note that due to the speculative nature of δ 18 O values of some of the major O bearing molecules, it can be difficult to use this to evaluate oxidation pathways quantitatively, but it may provide some additional qualitative constraints.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Assessing the Seasonal Dynamics of Nitrate and Sulfate Aerosols at the South Pole Utilizing Stable Isotopes

et al. 2019

View full text Add to dashboard Cite

Atmospheric nitrate (NO3− = particulate NO3− + gas‐phase nitric acid [HNO3]) and sulfate (SO42−) are key molecules that play important roles in numerous atmospheric processes. Here, the seasonal cycles of NO3− and total suspended particulate sulfate (SO42−(TSP)) were evaluated at the South Pole from aerosol samples collected weekly for approximately 10 months (26 January to 25 October) in 2002 and analyzed for their concentration and isotopic compositions. Aerosol NO3− was largely affected by snowpack emissions in which [NO3−] and δ15N(NO3−) were highest (49.3 ± 21.4 ng/m3, n = 8) and lowest (−47.0 ± 11.7‰, n = 5), respectively, during periods of sunlight in the interior of Antarctica. The seasonal cycle of Δ17O(NO3−) reflected tropospheric chemistry year‐round with lower values observed during sunlight periods and higher values observed during dark periods, reflecting shifts from HOx‐ to O3‐dominated oxidation chemistry. SO42−(TSP) concentrations were highest during austral summer and fall (86.7 ± 73.7 ng/m3, n = 18) and are indicated to be derived from dimethyl sulfide (DMS) emissions, as δ34S(SO42−)(TSP) values (18.5 ± 1.0‰, n = 10) were similar to literature δ34S(DMS) values. The seasonal cycle of Δ17O(SO42−)(TSP) exhibited minima during austral summer (0.9 ± 0.1‰, n = 5) and maxima during austral fall (1.3 ± 0.3‰, n = 6) and austral spring (1.6 ± 0.1‰, n = 5), indicating a shift from HOx‐ to O3‐dominated chemistry in the atmospheric derived SO42− component. Overall, the budgets of NO3− and SO42−(TSP) at the South Pole were complex functions of transport, localized chemistry, biological activity, and meteorological conditions, and these results will be important for interpretations of oxyanions in ice core records in the interior of Antarctica.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Assessing the Seasonal Dynamics of Nitrate and Sulfate Aerosols at the South Pole Utilizing Stable Isotopes

et al. 2019

View full text Add to dashboard Cite

show abstract

“…This factor was also seen to have moderate loadings of MS and Br − , 20-30 %, but with a larger degree of uncertainty. The atmospheric chemistry of NO − 3 is complex, involving a variety of sources, formation mechanisms, and destruction mechanisms; in particular, snow can act as both a sink and a source of atmospheric nitrogen oxides, further complicating the local NO − 3 cycle Ianniello et al, 2002;Morin et al, 2008;Fibiger et al, 2016). Furthermore, the complex processing of NO − 3 was demonstrated in the earlier deposition analysis of these data which suggested that gas-phase deposition was a dominant mechanism of NO − 3 transport to snow (Macdonald et al, 2017).…”

Section: Factor 5: Nitratementioning

confidence: 99%

“…This correlation with H + is in agreement with this factor's low neutralization ratio of 0.04. The low fall/spring levels of this factor may reflect the loss of NO − 3 from snow through photolysis driven by the sunlight availability after polar sunrise (Morin et al, 2008;Fibiger et al, 2016). The highest NO − 3 levels were observed when photolysis was inhibited during the polar sunset from mid-October to late February.…”

Section: Factor 5: Nitratementioning

confidence: 99%

Temporally delineated sources of major chemical species in high Arctic snow

et al. 2018

View full text Add to dashboard Cite

Abstract. Long-range transport of aerosol from lower latitudes to the high Arctic may be a significant contributor to climate forcing in the Arctic. To identify the sources of key contaminants entering the Canadian High Arctic an intensive campaign of snow sampling was completed at Alert, Nunavut, from September 2014 to June 2015. Fresh snow samples collected every few days were analyzed for black carbon, major ions, and metals, and this rich data set provided an opportunity for a temporally refined source apportionment of snow composition via positive matrix factorization (PMF) in conjunction with FLEXPART (FLEXible PARTicle dispersion model) potential emission sensitivity analysis. Seven source factors were identified: sea salt, crustal metals, black carbon, carboxylic acids, nitrate, noncrustal metals, and sulfate. The sea salt and crustal factors showed good agreement with expected composition and primarily northern sources. High loadings of V and Se onto Factor 2, crustal metals, was consistent with expected elemental ratios, implying these metals were not primarily anthropogenic in origin. Factor 3, black carbon, was an acidic factor dominated by black carbon but with some sulfate contribution over the winter-haze season. The lack of K + associated with this factor, a Eurasian source, and limited known forest fire events coincident with this factor's peak suggested a predominantly anthropogenic combustion source. Factor 4, carboxylic acids, was dominated by formate and acetate with a moderate correlation to available sunlight and an oceanic and North American source. A robust identification of this factor was not possible; however, atmospheric photochemical reactions, ocean microlayer reaction, and biomass burning were explored as potential contributors. Factor 5, nitrate, was an acidic factor dominated by NO − 3 , with a likely Eurasian source and mid-winter peak. The isolation of NO − 3 on a separate factor may reflect its complex atmospheric processing, though the associated source region suggests possibly anthropogenic precursors. Factor 6, non-crustal metals, showed heightened loadings of Sb, Pb, and As, and correlation with other metals traditionally associated with industrial activities. Similar to Factor 3 and 5, this factor appeared to be largely Eurasian in origin. Factor 7, sulfate, was dominated by SO 2− 4 and MS with a fall peak and high acidity. Coincident volcanic activity and northern source regions may suggest a processed SO 2 source of this factor.

show abstract

“…This factor was also seen to have moderate loadings of MSA and Br -, 20-30%, but with a larger degree of uncertainty. The atmospheric chemistry of NO3 -is complex, involving a 25 variety of sources, formation mechanisms, and destruction mechanisms; in particular, snow can act as both a sink and a source of atmospheric nitrogen oxides, further complicating the local NO3 -cycle (Morin et al, 2008;Fibiger et al, 2016).…”

Section: Factor 5: Nitratementioning

confidence: 99%