Atmospheric VOC measurements at a High Arctic site: characteristics and source apportionment

Pernov, Jakob; Bossi, Rossana; Lebourgeois, Thibaut; Nøjgaard, Jacob Klenø; Holzinger, Rupert; Hjorth, J.; Skov, Henrik

doi:10.5194/acp-2020-528

Cited by 9 publications

(13 citation statements)

References 92 publications

(162 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Highly variable mixing ratios of formic and acetic acid that are 3-5 times higher than those observed at TFS (formic acid 1.23 ± 0.63 ppbv, acetic acid 1.13 ± 1.54 ppbv; Mungall et al, 2018) were observed under diverse environmental conditions (cold, cloudy and warm, sunny) during early summer near the ocean in Alert, Nunavut, Canada. However, Pernov et al (2021) reported measurements (with 1σ in parenthesis) of formic (0.45 ± 0.37 ppbv) and acetic acid (0.20 ± 0.15 ppbv) in Greenland that are in closer agreement to our observed values. Previous global simulations of acetaldehyde mixing ratios suggest there is between 50-200 pptv of acetaldehyde in the Alaskan Arctic tundra between the boundary layer and middle troposphere (Millet et al, 2010), with the highest mixing ratios correlated to high biogenic emissions and precursor alkenes.…”

Section: Major Vocs In the Alaskan Arctic Tundrasupporting

confidence: 92%

Atmospheric biogenic volatile organic compounds in the Alaskan Arctic tundra: constraints from measurements at Toolik Field Station

Selimovic

Ketcherside²,

Chaliyakunnel³

et al. 2022

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. The Arctic is a climatically sensitive region that has experienced warming at almost 3 times the global average rate in recent decades, leading to an increase in Arctic greenness and a greater abundance of plants that emit biogenic volatile organic compounds (BVOCs). These changes in atmospheric emissions are expected to significantly modify the overall oxidative chemistry of the region and lead to changes in VOC composition and abundance, with implications for atmospheric processes. Nonetheless, observations needed to constrain our current understanding of these issues in this critical environment are sparse. This work presents novel atmospheric in situ proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) measurements of VOCs at Toolik Field Station (TFS; 68∘38′ N, 149∘36' W), in the Alaskan Arctic tundra during May–June 2019. We employ a custom nested grid version of the GEOS-Chem chemical transport model (CTM), driven with MEGANv2.1 (Model of Emissions of Gases and Aerosols from Nature version 2.1) biogenic emissions for Alaska at 0.25∘ × 0.3125∘ resolution, to interpret the observations in terms of their constraints on BVOC emissions, total reactive organic carbon (ROC) composition, and calculated OH reactivity (OHr) in this environment. We find total ambient mole fraction of 78 identified VOCs to be 6.3 ± 0.4 ppbv (10.8 ± 0.5 ppbC), with overwhelming (> 80 %) contributions are from short-chain oxygenated VOCs (OVOCs) including methanol, acetone and formaldehyde. Isoprene was the most abundant terpene identified. GEOS-Chem captures the observed isoprene (and its oxidation products), acetone and acetaldehyde abundances within the combined model and observation uncertainties (±25 %), but underestimates other OVOCs including methanol, formaldehyde, formic acid and acetic acid by a factor of 3 to 12. The negative model bias for methanol is attributed to underestimated biogenic methanol emissions for the Alaskan tundra in MEGANv2.1. Observed formaldehyde mole fractions increase exponentially with air temperature, likely reflecting its biogenic precursors and pointing to a systematic model underprediction of its secondary production. The median campaign-calculated OHr from VOCs measured at TFS was 0.7 s−1, roughly 5 % of the values typically reported in lower-latitude forested ecosystems. Ten species account for over 80 % of the calculated VOC OHr, with formaldehyde, isoprene and acetaldehyde together accounting for nearly half of the total. Simulated OHr based on median-modeled VOCs included in GEOS-Chem averages 0.5 s−1 and is dominated by isoprene (30 %) and monoterpenes (17 %). The data presented here serve as a critical evaluation of our knowledge of BVOCs and ROC budgets in high-latitude environments and represent a foundation for investigating and interpreting future warming-driven changes in VOC emissions in the Alaskan Arctic tundra.

show abstract

Section: Major Vocs In the Alaskan Arctic Tundrasupporting

confidence: 92%

Atmospheric biogenic volatile organic compounds in the Alaskan Arctic tundra: constraints from measurements at Toolik Field Station

Selimovic

Ketcherside²,

Chaliyakunnel³

et al. 2022

Atmos. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Based on atmospheric measurements and correlations with DMS, the Canadian Arctic sea ice zone has been suspected to be a sink for methanol and acetone (Sjostedt et al, 2012), and a source for other oxygenated VOCs produced in the sea surface microlayer from photochemical activity (Mungall et al, 2017(Mungall et al, , 2018. Atmospheric measurements in east Greenland find that the correlation between DMS and acetone air mixing ratios changes depending on the season (Pernov et al, 2020), pointing towards seasonal changes in seawater biogeochemistry affecting emissions of these gases.…”

Section: Introductionmentioning

confidence: 99%

Sea ice concentration impacts dissolved organic gases in the Canadian Arctic

et al. 2022

View full text Add to dashboard Cite

Abstract. The marginal sea ice zone has been identified as a source of different climate-active gases to the atmosphere due to its unique biogeochemistry. However, it remains highly undersampled, and the impact of summertime changes in sea ice concentration on the distributions of these gases is poorly understood. To address this, we present measurements of dissolved methanol, acetone, acetaldehyde, dimethyl sulfide, and isoprene in the sea ice zone of the Canadian Arctic from the surface down to 60 m. The measurements were made using a segmented flow coil equilibrator coupled to a proton-transfer-reaction mass spectrometer. These gases varied in concentrations with depth, with the highest concentrations generally observed near the surface. Underway (3–4 m) measurements showed higher concentrations in partial sea ice cover compared to ice-free waters for most compounds. The large number of depth profiles at different sea ice concentrations enables the proposition of the likely dominant production processes of these compounds in this area. Methanol concentrations appear to be controlled by specific biological consumption processes. Acetone and acetaldehyde concentrations are influenced by the penetration depth of light and stratification, implying dominant photochemical sources in this area. Dimethyl sulfide and isoprene both display higher surface concentrations in partial sea ice cover compared to ice-free waters due to ice edge blooms. Differences in underway concentrations based on sampling region suggest that water masses moving away from the ice edge influences dissolved gas concentrations. Dimethyl sulfide concentrations sometimes display a subsurface maximum in ice -free conditions, while isoprene more reliably displays a subsurface maximum. Surface gas concentrations were used to estimate their air–sea fluxes. Despite obvious in situ production, we estimate that the sea ice zone is absorbing methanol and acetone from the atmosphere. In contrast, dimethyl sulfide and isoprene are consistently emitted from the ocean, with marked episodes of high emissions during ice-free conditions, suggesting that these gases are produced in ice-covered areas and emitted once the ice has melted. Our measurements show that the seawater concentrations and air–sea fluxes of these gases are clearly impacted by sea ice concentration. These novel measurements and insights will allow us to better constrain the cycling of these gases in the polar regions and their effect on the oxidative capacity and aerosol budget in the Arctic atmosphere.

show abstract

“…Why did you use two different trajectory lengths? Additionally, I would recommend the use of shorter back trajectories (typically 5-7 days max) as uncertainties increase with time along the way (Stohl, 1998). I would also like to see a more critical discussion on back trajectories; they only give a general indication of source regions.…”

Section: -Biomass Burningmentioning

confidence: 99%

Reviewer#2

2020

View full text Add to dashboard Cite

by Pernov et al. reports atmospheric non-methane volatile organic compounds (VOCs) measurements at Villum Research Station at Station Nord, Greenland, from April to October 2018. Given the scarcity of VOC measurements in the Arctic and the significance of VOCs in the background atmosphere (formation of ozone, CO, and aerosols), this study will make a valuable contribution to the body of literature. The manuscript is overall well written and structured. My main concern is that the figures do not support the discussion and conclusions (see comments below). Additionally, the introduction could be more succinct.

show abstract

Atmospheric VOC measurements at a High Arctic site: characteristics and source apportionment

Cited by 9 publications

References 92 publications

Atmospheric biogenic volatile organic compounds in the Alaskan Arctic tundra: constraints from measurements at Toolik Field Station

Atmospheric biogenic volatile organic compounds in the Alaskan Arctic tundra: constraints from measurements at Toolik Field Station

Sea ice concentration impacts dissolved organic gases in the Canadian Arctic

Reviewer#2

Contact Info

Product

Resources

About