Low Ozone Episodes at Amphitrite Point Marine Boundary Layer Observatory, British Columbia, Canada

McKendry, Ian G.; Christensen, E.; Schiller, C. L.; Vingarzan, Roxanne; Macdonald, A. M.; Li, Yimei

doi:10.1080/07055900.2014.910164

Cited by 12 publications

(14 citation statements)

References 29 publications

(37 reference statements)

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“…The main mode of winter and fall, and the second mode of summer monsoon season displayed similar concentrations, which comprised the primary mode of O 3 distributions observed at IORS. O 3 levels are known to exhibit lower variability at remote sites and rural areas (McKendry et al, 2014;Oltmans and Levy II, 1994). However, the results of this study challenge those of previous studies.…”

Section: Ozone Variationscontrasting

confidence: 57%

Variations of surface ozone at Ieodo Ocean Research Station in the East China Sea and the influence of Asian outflows

et al. 2015

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Section: Ozone Variationscontrasting

confidence: 57%

Variations of surface ozone at Ieodo Ocean Research Station in the East China Sea and the influence of Asian outflows

et al. 2015

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“…The back trajectories showed that ODEs were characterized by light onshore or alongshore winds and that the air masses generally originated in the MBL, i.e., had a marine origin. Overall, the evidence indicated that the ODEs at APO are caused by a non-photochemical coastal zone process that extends over a spatial scale of tens of kilometres (McKendry et al, 2014).…”

Section: Introductionmentioning

confidence: 93%

Biogenic Emissions and Nocturnal Ozone Depletion Events at the Amphitrite Point Observatory on Vancouver Island

et al. 2017

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Routine monitoring stations on the west coast of North America serve to monitor baseline levels of criteria pollutants such as ozone (O3) arriving from the Pacific Ocean. In Canada, the Amphitrite Point Observatory (APO) on Vancouver Island has been added to this network to provide regional baseline measurements. In 2014, McKendry and co-workers reported frequent nocturnal O3 depletion events (ODEs) at APO that generally correlated with alongshore winds, elevated concentrations of carbon dioxide (CO2) and stable boundary layer conditions, but whose cause (or causes) has (have) remained unclear.This manuscript presents results from the Ozone-depleting Reactions in a Coastal Atmosphere (ORCA) campaign, which took place in July, 2015 to further investigate ODEs at APO. In addition to the long-term measurements at the site (e.g., of CO2 and O3 mixing ratios), abundances of biogenic volatile organic compounds (BVOC) and aerosol size distributions were quantified. ODEs were observed on the majority of measurement nights and were characterized by a simultaneous increase of CO2 and BVOC abundances, in particular of limonene, a terpene 2.5 more reactive with respect to oxidation of O3 than other monoterpenes.Back trajectory calculations showed that ODEs occurred mainly in air masses that originated from the WNW where the air would have travelled parallel to the coastline and above kelp forests. Head space analyses of sea weed samples showed that bull kelp is a source of gas-phase limonene, consistent with its high relative abundance in air masses from the WNW sector. However, the enhanced terpene and CO2 content showed that the air likely also came in contact with terrestrial vegetation via mesoscale transport phenomena (such as slope flows and land-sea breeze circulations) that were generally poorly captured by the back trajectories. This absence of aerosol growth during ODEs indicates that dry deposition is likely the primary O3 loss mechanism.

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“…At a freezing temperature of −20 • C and for a diameter of 0.1 µm, approximately 1 in 10 5 particles acted as an INP, while for a diameter of 10 µm, approximately 1 in 100 particles acted as an INP. A study of residuals of mixed-phase clouds by Mertes et al (2007) found that 1 in 10 supermicron particles acted as an INP, while only 1 in 10 3 submicron particles acted as an INP. Huffman et al (2013) studied INPs collected at a semi-arid pine forest in Colorado, USA.…”

Section: Ice-nucleating Ability On a Per Number Basismentioning

confidence: 99%

Ice-nucleating ability of aerosol particles and possible sources at three coastal marine sites

Irish

Mason

et al. 2018

Atmos. Chem. Phys.

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Abstract. Despite the importance of ice-nucleating particles (INPs) for climate and precipitation, our understanding of these particles is far from complete. Here, we investigated INPs at three coastal marine sites in Canada, two at mid-latitude (Amphitrite Point and Labrador Sea) and one in the Arctic (Lancaster Sound). For Amphitrite Point, 23 sets of samples were analyzed, and for Labrador Sea and Lancaster Sound, one set of samples was analyzed for each location. At all three sites, the ice-nucleating ability on a per number basis (expressed as the fraction of aerosol particles acting as an INP) was strongly dependent on the particle size. For example, at diameters of around 0.2 µm, approximately 1 in 106 particles acted as an INP at −25 ∘C, while at diameters of around 8 µm, approximately 1 in 10 particles acted as an INP at −25 ∘C. The ice-nucleating ability on a per surface-area basis (expressed as the surface active site density, ns) was also dependent on the particle size, with larger particles being more efficient at nucleating ice. The ns values of supermicron particles at Amphitrite Point and Labrador Sea were larger than previously measured ns values of sea spray aerosols, suggesting that sea spray aerosols were not a major contributor to the supermicron INP population at these two sites. Consistent with this observation, a global model of INP concentrations under-predicted the INP concentrations when assuming only marine organics as INPs. On the other hand, assuming only K-feldspar as INPs, the same model was able to reproduce the measurements at a freezing temperature of −25 ∘C, but under-predicted INP concentrations at −15 ∘C, suggesting that the model is missing a source of INPs active at a freezing temperature of −15 ∘C.

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Low Ozone Episodes at Amphitrite Point Marine Boundary Layer Observatory, British Columbia, Canada

Cited by 12 publications

References 29 publications

Variations of surface ozone at Ieodo Ocean Research Station in the East China Sea and the influence of Asian outflows

Variations of surface ozone at Ieodo Ocean Research Station in the East China Sea and the influence of Asian outflows

Biogenic Emissions and Nocturnal Ozone Depletion Events at the Amphitrite Point Observatory on Vancouver Island

Ice-nucleating ability of aerosol particles and possible sources at three coastal marine sites

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