scholarly journals Impact of Biomass Burning emission on total peroxy nitrates: fire plume identification during the BORTAS campaign

2016 ◽  
Author(s):  
Eleonora Aruffo ◽  
Fabio Biancofiore ◽  
Piero Di Carlo ◽  
Marcella Busilacchio ◽  
Marco Verdecchia ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atmospheric Pressure ◽  
Input Data ◽  
Thermal Dissociation ◽  
Ann Model ◽  
Fire Plume ◽  
Pressure Threshold ◽  
Peroxy Nitrates ◽  
The Impact

Abstract. The total peroxy nitrates (∑PNs) concentrations have been measured using a thermal dissociation laser induced fluorescence (TD-LIF) instrument during the BORTAS campaign, which focused on the impact of boreal biomass burning emissions on air quality in the Northern hemisphere. The strong correlation observed between the ∑PNs concentrations and those of the carbon monoxide (CO), a well-known pyrogenic tracer, suggests the possible use of the ∑PNs concentrations as marker of the biomass burning (BB) plumes. We applied both statistical and percentile methods to the ∑PNs concentrations, comparing the percentage of BB plume selected using these methods with the percentage evaluated applying the approaches usually used in literature. Moreover, adding the pressure threshold (~ 750 hPa) to ∑PNs, HCN and CO, as ancillary parameter, the BB plume identification is improved. An artificial recurrent neural network (ANN) model was adapted to simulate the concentrations of ∑PNs and the HCN including as input parameters ∑PNs, HCN, CO and atmospheric pressure, to verify the specific role of these input data to better identify BB plumes.

scholarly journals Impact of biomass burning emission on total peroxy nitrates: fire plume identification during the BORTAS campaign

2016 ◽  
Vol 9 (11) ◽  
pp. 5591-5606 ◽  
Author(s):  
Eleonora Aruffo ◽  
Fabio Biancofiore ◽  
Piero Di Carlo ◽  
Marcella Busilacchio ◽  
Marco Verdecchia ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atmospheric Pressure ◽  
Thermal Dissociation ◽  
Ann Model ◽  
Fire Plume ◽  
Pressure Threshold ◽  
Peroxy Nitrates ◽  
Artificial Neural Network Ann ◽  
The Impact

Abstract. Total peroxy nitrate ( ∑ PN) concentrations have been measured using a thermal dissociation laser-induced fluorescence (TD-LIF) instrument during the BORTAS campaign, which focused on the impact of boreal biomass burning (BB) emissions on air quality in the Northern Hemisphere. The strong correlation observed between the  ∑ PN concentrations and those of carbon monoxide (CO), a well-known pyrogenic tracer, suggests the possible use of the  ∑ PN concentrations as marker of the BB plumes. Two methods for the identification of BB plumes have been applied: (1)  ∑ PN concentrations higher than 6 times the standard deviation above the background and (2)  ∑ PN concentrations higher than the 99th percentile of the  ∑ PNs measured during a background flight (B625); then we compared the percentage of BB plume selected using these methods with the percentage evaluated, applying the approaches usually used in literature. Moreover, adding the pressure threshold ( ∼  750 hPa) as ancillary parameter to  ∑ PNs, hydrogen cyanide (HCN) and CO, the BB plume identification is improved. A recurrent artificial neural network (ANN) model was adapted to simulate the concentrations of  ∑ PNs and HCN, including nitrogen oxide (NO), acetonitrile (CH3CN), CO, ozone (O3) and atmospheric pressure as input parameters, to verify the specific role of these input data to better identify BB plumes.

scholarly journals Production of peroxy nitrates in boreal biomass burning plumes over Canada during the BORTAS campaign

2016 ◽  
Vol 16 (5) ◽  
pp. 3485-3497 ◽  
Author(s):  
Marcella Busilacchio ◽  
Piero Di Carlo ◽  
Eleonora Aruffo ◽  
Fabio Biancofiore ◽  
Cesare Dari Salisburgo ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Forest Fire ◽  
Biomass Burning ◽  
Forest Fires ◽  
Chemical Mechanism ◽  
Fire Emissions ◽  
Fire Plumes ◽  
Peroxy Nitrates ◽  
In Fire ◽  
The Impact

Abstract. The observations collected during the BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS) campaign in summer 2011 over Canada are analysed to study the impact of forest fire emissions on the formation of ozone (O3) and total peroxy nitrates ∑PNs, ∑ROONO2). The suite of measurements on board the BAe-146 aircraft, deployed in this campaign, allows us to calculate the production of O3 and of  ∑PNs, a long-lived NOx reservoir whose concentration is supposed to be impacted by biomass burning emissions. In fire plumes, profiles of carbon monoxide (CO), which is a well-established tracer of pyrogenic emission, show concentration enhancements that are in strong correspondence with a significant increase of concentrations of ∑PNs, whereas minimal increase of the concentrations of O3 and NO2 is observed. The ∑PN and O3 productions have been calculated using the rate constants of the first- and second-order reactions of volatile organic compound (VOC) oxidation. The ∑PN and O3 productions have also been quantified by 0-D model simulation based on the Master Chemical Mechanism. Both methods show that in fire plumes the average production of ∑PNs and O3 are greater than in the background plumes, but the increase of ∑PN production is more pronounced than the O3 production. The average ∑PN production in fire plumes is from 7 to 12 times greater than in the background, whereas the average O3 production in fire plumes is from 2 to 5 times greater than in the background. These results suggest that, at least for boreal forest fires and for the measurements recorded during the BORTAS campaign, fire emissions impact both the oxidized NOy and O3,  but (1 ∑PN production is amplified significantly more than O3 production and (2) in the forest fire plumes the ratio between the O3 production and the ∑PN production is lower than the ratio evaluated in the background air masses, thus confirming that the role played by the ∑PNs produced during biomass burning is significant in the O3 budget. The implication of these observations is that fire emissions in some cases, for example boreal forest fires and in the conditions reported here, may influence more long-lived precursors of O3 than short-lived pollutants, which in turn can be transported and eventually diluted in a wide area.

scholarly journals Modelling of an Atmospheric–Pressure Air Glow Discharge Operating in High–Gas Temperature Regimes: The Role of the Associative Ionization Reactions Involving Excited Atoms

Plasma ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 12-26
Author(s):  
Ezequiel Cejas ◽  
Beatriz Mancinelli ◽  
Leandro Prevosto
Keyword(s):  
Atmospheric Pressure ◽  
Vibrational Excitation ◽  
Thermal Dissociation ◽  
Ionization Mechanism ◽  
Gas Temperature ◽  
Excited Atoms ◽  
Temperature Regimes ◽  
Ionization Reaction ◽  
Associative Ionization

A model of a stationary glow-type discharge in atmospheric-pressure air operated in high-gas-temperature regimes (1000 K < Tg < 6000 K), with a focus on the role of associative ionization reactions involving N(2D,2P)-excited atoms, is developed. Thermal dissociation of vibrationally excited nitrogen molecules, as well as electronic excitation from all the vibrational levels of the nitrogen molecules, is also accounted for. The calculations show that the near-threshold associative ionization reaction, N(2D) + O(3P) → NO+ + e, is the major ionization mechanism in air at 2500 K < Tg < 4500 K while the ionization of NO molecules by electron impact is the dominant mechanism at lower gas temperatures and the high-threshold associative ionization reaction involving ground-state atoms dominates at higher temperatures. The exoergic associative ionization reaction, N(2P) + O(3P) → NO+ + e, also speeds up the ionization at the highest temperature values. The vibrational excitation of the gas significantly accelerates the production of N2(A3∑u+) molecules, which in turn increases the densities of excited N(2D,2P) atoms. Because the electron energy required for the excitation of the N2(A3∑u+) state from N2(X1∑g+, v) molecules (e.g., 6.2 eV for v = 0) is considerably lower than the ionization energy (9.27 eV) of the NO molecules, the reduced electric field begins to noticeably fall at Tg > 2500 K. The calculated plasma parameters agree with the available experimental data.

The impact of atmospheric pressure change and rainfall for triggering landslides during weather events

2020 ◽  
Author(s):  
Lucas Pelascini ◽  
Philippe Steer ◽  
Laurent Longuevergne ◽  
Dimitri Lague
Keyword(s):  
Pressure Drop ◽  
Slope Stability ◽  
Atmospheric Pressure ◽  
Weather Conditions ◽  
Pressure Change ◽  
Weather Events ◽  
Pressure Changes ◽  
The Impact ◽  
Landslide Triggering

&lt;p&gt;Landslides are a complex phenomenon which triggering depends on both intrinsic properties of soils and rocks and external influences such as the action of weather conditions, or earthquakes. Around 6,000 landslides failed the 6&lt;sup&gt;th&lt;/sup&gt; of September 2018 during the Mw 6.6 Hokkaido Eastern Iburi earthquake (Japan), one day after the typhoon Jebi hit the region. If the ground acceleration induced by the seismic waves likely played a major role in the triggering of these landslides, it is unclear how it compares to the respective role of rainfall and atmospheric pressure drop induced by the typhoon. The aim of this work is therefore to investigate the influence of weather conditions on landslide triggering, and more specifically to characterize the relative contributions of rainfall and atmospheric pressure changes on slope stability.&lt;/p&gt;&lt;p&gt;For this purpose, a simple model is developed to describe the two mechanisms and to compare their respective impact on slope stability. The model considers a homogeneous isotropic tilted infinite half-space in one dimension. Slope stability is estimated using a safety factor and a Mohr-Coulomb criterion. In the static case, groundwater is accounted for by adding an unconfined aquifer into the model. Analytical models based on diffusion equations have been used to describe the impact of rainfall and atmospheric pressure changes on slope stability (Iverson, 2000; Schulz, 2009). Extracting a response function from these models allows us to compute the stability change due to any rainfall or pressure time series. The model parameters are taken for a typical slope in Taiwan tilted with a 25&amp;#176; angle and with characteristics of a fully saturated loamy soil at 4 m depth and put under conditions similar to the Morakot typhoon, with more than 240 mm of rain on a 24 h period and an associate atmospheric pressure drop of 4 kPa.&lt;/p&gt;&lt;p&gt;Atmospheric pressure change and rainfall impacts the media in a very different way despite being associated to the same physical phenomenon, pressure diffusion. The atmospheric effect is instantaneous and directly affects the effective stress with a maximum of 4 kPa. This effect decreases over time while the pore pressure is adjusted to the atmosphere. The rainfall effect is delayed in time but has a greater impact on the effective stress, reaching 11.7 kPa almost 2 days after the end of the rainfall event. While atmospheric pressure does not change significantly the safety factor, it can exacerbate the effect of rainfall and advance the failure in time because of the respective temporal lag between the 2 processes. &amp;#160;Therefore, this study may lead to a better understanding of the effect of weather events such as typhoons on landslide triggering and slope stability. Our results call for revisiting in a more systematic approach the role of atmospheric pressure change on landslide triggering during extreme weather events. Because a 1D model may hide some effects associated to hillslope geometry, we then consider 2D numerical models which allow us to offer some first insights on slope stability during weather events, accounting for topography.&lt;/p&gt;

scholarly journals Simulating the forest fire plume dispersion, chemistry, and aerosol formation using SAM-ASP version 1.0

2020 ◽  
Vol 13 (9) ◽  
pp. 4579-4593
Author(s):  
Chantelle R. Lonsdale ◽  
Matthew J. Alvarado ◽  
Anna L. Hodshire ◽  
Emily Ramnarine ◽  
Jeffrey R. Pierce
Keyword(s):  
Biomass Burning ◽  
Process Model ◽  
Large Scale ◽  
Trace Gases ◽  
Regional Scale ◽  
Process Models ◽  
Plume Dispersion ◽  
Aerosol Formation ◽  
Fire Plume ◽  
The Impact

Abstract. Biomass burning is a major source of trace gases and aerosols that can ultimately impact health, air quality, and climate. Global and regional-scale three-dimensional Eulerian chemical transport models (CTMs) use estimates of the primary emissions from fires and can unphysically mix them across large-scale grid boxes, leading to incorrect estimates of the impact of biomass burning events. On the other hand, plume-scale process models allow for explicit simulation and examination of the chemical and physical transformations of trace gases and aerosols within biomass burning smoke plumes, and they may be used to develop parameterizations of this aging process for coarser grid-scale models. Here we describe the coupled SAM-ASP plume-scale process model, which consists of coupling the large-eddy simulation model, the System for Atmospheric Modelling (SAM), with the detailed gas and aerosol chemistry model, the Aerosol Simulation Program (ASP). We find that the SAM-ASP version 1.0 model is able to correctly simulate the dilution of CO in a California chaparral smoke plume, as well as the chemical loss of NOx, HONO, and NH3 within the plume, the formation of PAN and O3, the loss of OA, and the change in the size distribution of aerosols as compared to measurements and previous single-box model results. The newly coupled model is able to capture the cross-plume vertical and horizontal concentration gradients as the fire plume evolves downwind of the emission source. The integration and evaluation of SAM-ASP version 1.0 presented here will support the development of parameterizations of near-source biomass burning chemistry that can be used to more accurately simulate biomass burning chemical and physical transformations of trace gases and aerosols within coarser grid-scale CTMs.

scholarly journals Low Temperature and Low UV Indexes Correlated with Peaks of Influenza Virus Activity in Northern Europe during 2010–2018

Viruses ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 207 ◽  
Author(s):  
Aleksandr Ianevski ◽  
Eva Zusinaite ◽  
Nastassia Shtaida ◽  
Hannimari Kallio-Kokko ◽  
Miia Valkonen ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Low Temperature ◽  
Atmospheric Pressure ◽  
Meteorological Factors ◽  
Northern Europe ◽  
Uv Index ◽  
Influenza Outbreaks ◽  
The Impact

With the increasing pace of global warming, it is important to understand the role of meteorological factors in influenza virus (IV) epidemics. In this study, we investigated the impact of temperature, UV index, humidity, wind speed, atmospheric pressure, and precipitation on IV activity in Norway, Sweden, Finland, Estonia, Latvia and Lithuania during 2010–2018. Both correlation and machine learning analyses revealed that low temperature and UV indexes were the most predictive meteorological factors for IV epidemics in Northern Europe. Our in vitro experiments confirmed that low temperature and UV radiation preserved IV infectivity. Associations between these meteorological factors and IV activity could improve surveillance and promote development of accurate predictive models for future influenza outbreaks in the region.

scholarly journals Simulating Forest Fire Plume Dispersion, Chemistry, and Aerosol Formation Using SAM-ASP version 1.0

2019 ◽  
Author(s):  
Chantelle R. Lonsdale ◽  
Matthew J. Alvarado ◽  
Anna L. Hodshire ◽  
Emily Ramnarine ◽  
Jeffrey R. Pierce
Keyword(s):  
Biomass Burning ◽  
Process Model ◽  
Large Scale ◽  
Trace Gases ◽  
Regional Scale ◽  
Process Models ◽  
Plume Dispersion ◽  
Aerosol Formation ◽  
Fire Plume ◽  
The Impact

Abstract. Biomass burning is a major source of trace gases and aerosols that can ultimately impact health, air quality, and climate. Global and regional-scale three-dimensional Eulerian chemical transport models (CTMs) use estimates of the primary emissions from fires and can unphysically mix them across large-scale grid boxes, leading to incorrect estimates of the impact of biomass burning events. On the other hand, plume-scale process models allow for explicit simulation and examination of the chemical and physical transformations of trace gases and aerosols within biomass burning smoke plumes, and they may be used to develop parameterizations of this aging process for coarser grid-scale models. Here we describe the coupled SAM-ASP plume-scale process model, which consists of coupling the large-eddy simulation model, the System for Atmospheric Modelling (SAM) version 1.0, with the detailed gas and aerosol chemistry model, the Aerosol Simulation Program (ASP). We find that the SAM-ASP version 1.0 model is able to correctly simulate the dilution of CO in a California chaparral smoke plume, as well as the chemical loss of NOx, HONO, and NH3 within the plume, the formation of PAN and O3, the loss of OA, and the change in the size distribution of aerosols as compared to measurements and previous single-box model results. The newly coupled model is able to capture the cross-plume vertical and horizontal concentration gradients as the fire plume evolves downwind of the emission source. The integration and evaluation of SAM-ASP presented here will support the development of parameterizations of near-source biomass burning chemistry that can be used to more accurately simulate biomass burning chemical and physical transformations of trace gases and aerosols within coarser grid-scale CTMs.

scholarly journals Production of peroxy nitrates in boreal biomass burning plumes over Canada during the BORTAS campaign

2015 ◽  
Vol 15 (5) ◽  
pp. 6009-6040
Author(s):  
M. Busilacchio ◽  
P. Di Carlo ◽  
E. Aruffo ◽  
F. Biancofiore ◽  
C. D. Salisburgo ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Forest Fire ◽  
Biomass Burning ◽  
Forest Fires ◽  
Indirect Evidence ◽  
Fire Emissions ◽  
Fire Plumes ◽  
Peroxy Nitrates ◽  
In Fire ◽  
The Impact

Abstract. The observations collected during the BORTAS campaign in summer 2011 over Canada are analysed to study the impact of forest fire emissions on the formation of ozone (O3) and total peroxy nitrates (ΣPNs, ΣROONO2). The suite of measurements on board the BAe-146 aircraft, deployed in this campaign, allows us to calculate the production of O3 and of ΣPNs, a long lived O3 reservoir whose concentration is supposed to be impacted by biomass burning emissions. In fire plumes, profiles of carbon monoxide (CO), which is a well-established tracer of pyrogenic emission, show concentration enhancements that are in strong correspondence with a significant increase of ΣPNs concentrations, whereas minimal increase of the concentrations of O3 and NO2 are observed. In those fire plumes the average ΣPNs production is 12 times greater than in the background plumes, by contrast the average O3 production is only 5 times greater. These results suggest that, at least for boreal forest fires and for the measurements recorded during the BORTAS campaign, fire emissions impact both the oxidized NOy and O3, but: (1) ΣPNs production is affected significantly respect to the O3 production and (2) in the forest fire plumes the ratio between the ΣPNs production and the O3 production is lower than the ratio evaluated in the background air masses, thus confirming that the role played by the ΣPNs produced during biomass burning is significant in the O3 budget. These observations are consistent with elevated production of PAN and concurrent low production (or sometimes loss) of O3 observed in some another campaigns (i.e. ARCTAS-B) focused on forest fire emissions. Moreover our observations extend ARCTAS-B results since PAN is one of the compounds included in the ΣPNs family detected during BORTAS. The implication of these observations is that fire emissions in some cases, for example Boreal forest fires and in the conditions reported here, may influence more long lived precursors of O3 than short lived pollutants, which in turn can be transported and eventually diluted in a wide area. These observations provide additional indirect evidence that O3 production may be enhanced as plumes from forest fires age.

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