Particle formation due to SO2oxidation and high relative humidity in the remote marine boundary layer

1994 ◽  
Vol 99 (D12) ◽  
pp. 25607 ◽  
Author(s):  
Veli-Matti Kerminen ◽  
Anthony S. Wexler
Keyword(s):  
Boundary Layer ◽  
Relative Humidity ◽  
Marine Boundary Layer ◽  
Particle Formation ◽  
High Relative Humidity

scholarly journals Summertime observations of elevated levels of ultrafine particles in the high Arctic marine boundary layer

2017 ◽  
Vol 17 (8) ◽  
pp. 5515-5535 ◽  
Author(s):  
Julia Burkart ◽  
Megan D. Willis ◽  
Heiko Bozem ◽  
Jennie L. Thomas ◽  
Kathy Law ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Ultrafine Particles ◽  
Marine Boundary Layer ◽  
Ultrafine Particle ◽  
High Arctic ◽  
Particle Formation ◽  
Open Ocean ◽  
Biologically Active ◽  
The Arctic ◽  
Depositional Processes

Abstract. Motivated by increasing levels of open ocean in the Arctic summer and the lack of prior altitude-resolved studies, extensive aerosol measurements were made during 11 flights of the NETCARE July 2014 airborne campaign from Resolute Bay, Nunavut. Flights included vertical profiles (60 to 3000 m above ground level) over open ocean, fast ice, and boundary layer clouds and fogs. A general conclusion, from observations of particle numbers between 5 and 20 nm in diameter (N5 − 20), is that ultrafine particle formation occurs readily in the Canadian high Arctic marine boundary layer, especially just above ocean and clouds, reaching values of a few thousand particles cm−3. By contrast, ultrafine particle concentrations are much lower in the free troposphere. Elevated levels of larger particles (for example, from 20 to 40 nm in size, N20 − 40) are sometimes associated with high N5 − 20, especially over low clouds, suggestive of aerosol growth. The number densities of particles greater than 40 nm in diameter (N >  40) are relatively depleted at the lowest altitudes, indicative of depositional processes that will lower the condensation sink and promote new particle formation. The number of cloud condensation nuclei (CCN; measured at 0.6 % supersaturation) are positively correlated with the numbers of small particles (down to roughly 30 nm), indicating that some fraction of these newly formed particles are capable of being involved in cloud activation. Given that the summertime marine Arctic is a biologically active region, it is important to better establish the links between emissions from the ocean and the formation and growth of ultrafine particles within this rapidly changing environment.

scholarly journals Can new particle formation occur in the clean marine boundary layer?

2000 ◽  
Vol 105 (D21) ◽  
pp. 26531-26546 ◽  
Author(s):  
Liisa Pirjola ◽  
Colin D. O'Dowd ◽  
Ian M. Brooks ◽  
Markku Kulmala
Keyword(s):  
Boundary Layer ◽  
Marine Boundary Layer ◽  
Particle Formation ◽  
New Particle Formation

scholarly journals Iodine-mediated coastal particle formation: an overview of the Reactive Halogens in the Marine Boundary Layer (RHaMBLe) Roscoff coastal study

2010 ◽  
Vol 10 (6) ◽  
pp. 2975-2999 ◽  
Author(s):  
G. McFiggans ◽  
C. S. E. Bale ◽  
S. M. Ball ◽  
J. M. Beames ◽  
W. J. Bloss ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Ultrafine Particles ◽  
Marine Boundary Layer ◽  
Cloud Condensation Nuclei ◽  
Measurement Techniques ◽  
Ultrafine Particle ◽  
Molecular Iodine ◽  
Particle Formation ◽  
North West ◽  
Iodine Species

Abstract. This paper presents a summary of the measurements made during the heavily-instrumented Reactive Halogens in the Marine Boundary Layer (RHaMBLe) coastal study in Roscoff on the North West coast of France throughout September 2006. It was clearly demonstrated that iodine-mediated coastal particle formation occurs, driven by daytime low tide emission of molecular iodine, I2, by macroalgal species fully or partially exposed by the receding waterline. Ultrafine particle concentrations strongly correlate with the rapidly recycled reactive iodine species, IO, produced at high concentrations following photolysis of I2. The heterogeneous macroalgal I2 sources lead to variable relative concentrations of iodine species observed by path-integrated and in situ measurement techniques. Apparent particle emission fluxes were associated with an enhanced apparent depositional flux of ozone, consistent with both a direct O3 deposition to macroalgae and involvement of O3 in iodine photochemistry and subsequent particle formation below the measurement height. The magnitude of the particle formation events was observed to be greatest at the lowest tides with the highest concentrations of ultrafine particles growing to the largest sizes, probably by the condensation of anthropogenically-formed condensable material. At such sizes the particles should be able to act as cloud condensation nuclei at reasonable atmospheric supersaturations.

scholarly journals Iodine-mediated coastal particle formation: an overview of the Reactive Halogens in the Marine Boundary Layer (RHaMBLe) Roscoff coastal study

2009 ◽  
Vol 9 (6) ◽  
pp. 26421-26489 ◽  
Author(s):  
G. McFiggans ◽  
C. S. E. Bale ◽  
S. M. Ball ◽  
J. M. Beames ◽  
W. J. Bloss ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Ultrafine Particles ◽  
Marine Boundary Layer ◽  
Cloud Condensation Nuclei ◽  
Measurement Techniques ◽  
Ultrafine Particle ◽  
Molecular Iodine ◽  
Particle Formation ◽  
North West ◽  
Iodine Species

Abstract. This paper presents a summary of the measurements that were made during the heavily-instrumented Reactive Halogens in the Marine Boundary Layer (RHaMBLe) coastal study in Roscoff on the North West coast of France. It was clearly demonstrated that iodine-mediated coastal particle formation occurs, driven by daytime low tide emission of molecular iodine, I2, by macroalgal species fully or partially exposed by the receding waterline. Ultrafine particle concentrations strongly correlate with the rapidly recycled reactive iodine species, IO, produced at high concentrations following photolysis of I2. The heterogeneous macroalgal I2 sources lead to variable relative concentrations of iodine species observed by path-integrated and in situ measurement techniques. Apparent particle emission fluxes were associated with an enhanced apparent depositional flux of ozone, consistent with both a direct O3 deposition to macroalgae and involvement of O3 in iodine photochemistry and subsequent particle formation below the measurement height. The magnitude of the particle formation events was observed to be greatest at the lowest tides with higher concentrations of ultrafine particles growing to much larger sizes, probably by the condensation of anthropogenically-formed condensable material. At such sizes the particles should be able to act as cloud condensation nuclei at reasonable atmospheric supersaturations.

scholarly journals Explaining global surface aerosol number concentrations in terms of primary emissions and particle formation

2010 ◽  
Vol 10 (10) ◽  
pp. 4775-4793 ◽  
Author(s):  
D. V. Spracklen ◽  
K. S. Carslaw ◽  
J. Merikanto ◽  
G. W. Mann ◽  
C. L. Reddington ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Sulfuric Acid ◽  
Particle Number ◽  
Marine Boundary Layer ◽  
Sulfuric Acid Concentration ◽  
Particle Formation ◽  
Anthropogenic Sources ◽  
Secondary Source ◽  
Primary Particles ◽  
Activation Type

Abstract. We synthesised observations of total particle number (CN) concentration from 36 sites around the world. We found that annual mean CN concentrations are typically 300–2000 cm−3 in the marine boundary layer and free troposphere (FT) and 1000–10 000 cm−3 in the continental boundary layer (BL). Many sites exhibit pronounced seasonality with summer time concentrations a factor of 2–10 greater than wintertime concentrations. We used these CN observations to evaluate primary and secondary sources of particle number in a global aerosol microphysics model. We found that emissions of primary particles can reasonably reproduce the spatial pattern of observed CN concentration (R2=0.46) but fail to explain the observed seasonal cycle (R2=0.1). The modeled CN concentration in the FT was biased low (normalised mean bias, NMB=−88%) unless a secondary source of particles was included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB=−25%). Simulated CN concentrations in the continental BL were also biased low (NMB=−74%) unless the number emission of anthropogenic primary particles was increased or a mechanism that results in particle formation in the BL was included. We ran a number of simulations where we included an empirical BL nucleation mechanism either using the activation-type mechanism (nucleation rate, J, proportional to gas-phase sulfuric acid concentration to the power one) or kinetic-type mechanism (J proportional to sulfuric acid to the power two) with a range of nucleation coefficients. We found that the seasonal CN cycle observed at continental BL sites was better simulated by BL particle formation (R2=0.3) than by increasing the number emission from primary anthropogenic sources (R2=0.18). The nucleation constants that resulted in best overall match between model and observed CN concentrations were consistent with values derived in previous studies from detailed case studies at individual sites. In our model, kinetic and activation-type nucleation parameterizations gave similar agreement with observed monthly mean CN concentrations.

scholarly journals Marine Boundary Layer Cloud Feedbacks in a Constant Relative Humidity Atmosphere

2012 ◽  
Vol 69 (8) ◽  
pp. 2538-2550 ◽  
Author(s):  
Malte Rieck ◽  
Louise Nuijens ◽  
Bjorn Stevens
Keyword(s):  
Boundary Layer ◽  
Relative Humidity ◽  
Liquid Water ◽  
Radiative Forcing ◽  
Marine Boundary Layer ◽  
Surface Fluxes ◽  
Lapse Rate ◽  
Specific Humidity ◽  
Trade Wind ◽  
Positive Temperature

Abstract The mechanisms that govern the response of shallow cumulus, such as found in the trade wind regions, to a warming of the atmosphere in which large-scale atmospheric processes act to keep relative humidity constant are explored. Two robust effects are identified. First, and as is well known, the liquid water lapse rate increases with temperature and tends to increase the amount of water in clouds, making clouds more reflective of solar radiation. Second, and less well appreciated, the surface fluxes increase with the saturation specific humidity, which itself is a strong function of temperature. Using large-eddy simulations it is shown that the liquid water lapse rate acts as a negative feedback: a positive temperature increase driven by radiative forcing is reduced by the increase in cloud water and hence cloud albedo. However, this effect is more than compensated by a reduction of cloudiness associated with the deepening and relative drying of the boundary layer, driven by larger surface moisture fluxes. Because they are so robust, these effects are thought to underlie changes in the structure of the marine boundary layer as a result of global warming.

scholarly journals Production of HONO from heterogeneous uptake of NO<sub>2</sub> on illuminated TiO<sub>2</sub> aerosols measured by Photo-Fragmentation Laser Induced Fluorescence

2020 ◽  
Author(s):  
Joanna E. Dyson ◽  
Graham A. Boustead ◽  
Lauren T. Fleming ◽  
Mark Blitz ◽  
Daniel Stone ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Relative Humidity ◽  
Marine Boundary Layer ◽  
Laser Induced Fluorescence ◽  
Separate Experiment ◽  
Photon Flux ◽  
Uptake Coefficient ◽  
Mixing Ratios ◽  
Reactive Uptake Coefficient ◽  
Significant Production

Abstract. The rate of production of HONO from illuminated TiO2 aerosols in the presence of NO2 was measured using an aerosol flow tube coupled to a photo-fragmentation laser induced fluorescence detection apparatus. The reactive uptake coefficient of NO2 to form HONO, γNO2→HONO, was determined for NO2 mixing ratios in the range 34–400 ppb, with γNO2→HONO spanning the range (9.97 ± 3.52) × 10−6 to (1.26 ± 0.17) × 10−4 at a relative humidity of 15 ± 1 % and for a lamp photon flux of (1.63 ± 0.09) × 1016 photons cm−2 s −1 (integrated between 290 and 400 nm), which is similar to values of ambient actinic flux at midday. γNO2→HONO increased as a function of NO2 mixing ratio at low NO2 before peaking at (1.26 ± 0.17) × 10−4 at 51 ppb NO2 and then sharply decreasing at higher NO2 mixing ratios, rather than levelling off which would be indicative of surface saturation. The dependence of HONO production on relative humidity was also investigated, with a peak in production of HONO from TiO2 aerosol surfaces found at ~25 % RH. Possible mechanisms consistent with the observed trends in both the HONO production and reactive uptake coefficient were investigated using a zero-dimensional kinetic box model. The modelling studies supported a mechanism for HONO production on the aerosol surface involving two molecules of NO2, as well as a surface HONO loss mechanism which is dependent upon NO2. In a separate experiment, significant production of HONO was observed from illumination of mixed nitrate/TiO2 aerosols in the absence of NO2. However, no statistically significant production of HONO was seen from the illumination of pure nitrate aerosols. The rate of production of HONO observed from mixed nitrate/TiO2 aerosols was scaled to ambient conditions found at the Cape Verde Atmospheric Observatory (CVAO) in the remote tropical marine boundary layer. The rate of HONO production from aerosol particulate nitrate photolysis containing a photocatalyst was found to be similar to the missing HONO production rate necessary to reproduce observed concentrations of HONO at CVAO. These results provide evidence that particulate nitrate photolysis may have a significant impact on the production of HONO and hence NOx in the marine boundary layer where mixed aerosols containing nitrate and a photocatalytic species such as TiO2, as found in dust, are present.

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