The impact of cloud chemistry on photochemical oxidant formation

1985 ◽  
Vol 24 (4) ◽  
Author(s):  
Christian Seigneur ◽  
Pradeep Saxena
Keyword(s):  
Cloud Chemistry ◽  
Photochemical Oxidant ◽  
The Impact

scholarly journals Relationship between Changes over Time in Factors, Including the Impact of Meteorology on Photochemical Oxidant Concentration and Causative Atmospheric Pollutants in Kawasaki

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 446
Author(s):  
Akinori Fukunaga ◽  
Takaharu Sato ◽  
Kazuki Fujita ◽  
Daisuke Yamada ◽  
Shinya Ishida ◽  
...  
Keyword(s):  
Moving Average ◽  
Atmospheric Pollutants ◽  
Important Indicator ◽  
Photochemical Oxidant ◽  
Oxidant Concentration ◽  
Using Data ◽  
Changes Over Time ◽  
The Impact ◽  
The Relationship ◽  
The City

To clarify the relationship between changes in photochemical oxidants’ (Ox) concentrations and their precursors in Kawasaki, a series of analyses were conducted using data on Ox, their precursors, nitrogen oxides (NOx) and volatile organic compounds (VOCs), and meteorology that had been monitored throughout the city of Kawasaki for 30 years from 1990 to 2019. The trend in air temperature was upward, wind speed was downward, and solar radiation was upward, indicating an increasing trend in meteorological factors in which Ox concentrations tend to be higher. Between 1990 and 2013, the annual average Ox increased throughout Kawasaki and remained flat after that. The three-year moving average of the daily peak increased until 2015, and after that, it exhibited a slight decline. The amount of generated Ox is another important indicator. To evaluate this, a new indicator, the daytime production of photochemical oxidant (DPOx), was proposed. DPOx is defined by daytime averaged Ox concentrations less the previous day’s nighttime averaged Ox concentrations. The trend in DPOx from April to October has been decreasing since around 2006, and it was found that this indicator reflects the impact of reducing emissions of NOx and VOCs in Kawasaki.

scholarly journals Cloud-scale model intercomparison of chemical constituent transport in deep convection

2007 ◽  
Vol 7 (3) ◽  
pp. 8035-8085 ◽  
Author(s):  
M. C. Barth ◽  
S.-W. Kim ◽  
C. Wang ◽  
K. E. Pickering ◽  
L. E. Ott ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Chemical Reactivity ◽  
Chemical Constituents ◽  
Deep Convection ◽  
Convective Transport ◽  
Scale Model ◽  
Cloud Chemistry ◽  
Mixing Ratios ◽  
The Impact

Abstract. Transport and scavenging of chemical constituents in deep convection is important to understanding the composition of the troposphere and therefore chemistry-climate and air quality issues. High resolution cloud chemistry models have been shown to represent convective processing of trace gases quite well. To improve the representation of sub-grid convective transport and wet deposition in large-scale models, general characteristics, such as species mass flux, from the high resolution cloud chemistry models can be used. However, it is important to understand how these models behave when simulating the same storm. The intercomparison described here examines transport of six species. CO and O3, which are primarily transported, show good agreement among models and compare well with observations. Models that included lightning production of NOx reasonably predict NOx mixing ratios in the anvil compared with observations, but the NOx variability is much larger than that seen for CO and O3. Predicted anvil mixing ratios of the soluble species, HNO3, H2O2, and CH2O, exhibit significant differences among models, attributed to different schemes in these models of cloud processing including the role of the ice phase, the impact of cloud-modified photolysis rates on the chemistry, and the representation of the species chemical reactivity. The lack of measurements of these species in the convective outflow region does not allow us to evaluate the model results with observations.

A three-dimensional numerical simulation of sulfate transport and redistribution

2003 ◽  
Vol 81 (9) ◽  
pp. 1067-1094 ◽  
Author(s):  
V Spiridonov ◽  
M Curic
Keyword(s):  
Liquid Phase ◽  
Wet Deposition ◽  
Cloud Model ◽  
Chemical Species ◽  
Liquid Phase Oxidation ◽  
Atmospheric Pollutants ◽  
Total Sulfur ◽  
Cloud Chemistry ◽  
Phase Oxidation ◽  
The Impact

We have utilized a relatively sophisticated dynamic cloud model combined with standard bulk-parameterized microphysics and simple sulfur chemistry to explore the impact of deep convection on modification and transport of a suite of pollutants. Two base run simulation parameters are used to initialize the cloud-chemistry model. The simulation of the 6 July 1995 case, with continental polluted field initialization, has revealed that a convective storm generates strong vertical transport of gases and particulate compounds from the planetary boundary layer (PBL) to the upper troposphere (UT), perturbation of aerosol physical and chemical properties, modification of pollutant concentration, and change of the spatial distributions of chemical species. The early formation of precipitation and enhanced scavenging contributed to a registration of approximately 2.5 times the concentration of sulfate in the precipitation near the surface than in the air found at this level. The Spring case numerical experiment on 3 April 2000 with a chemical background taken from Macedonia, provided insight into the potential influence of the long-range transport of atmospheric pollutants and ascertained quantitative–qualitative information about processes by which acidic species are incorporated into precipitation. The model-computed parameters are in good agreement with observation. The average equivalent cloud water pH and rainwater pH when the higher acid precipitation occurs are about 5.0 and 4.5, respectively. The results from a number of sensitivity tests of cloud chemistry of the physical processes for the continental nonpolluted and continental polluted environments, indicate that nucleation and impact scavenging of aerosols account for between 20%–24% of the total sulfur mass removed by wet deposition. Liquid-phase oxidation contributes about 20%–28% of the sulfur content in precipitation. It means that neglecting liquid-phase oxidation when considering the chemistry in these clouds may lead to underestimates of about 20%–28% in sulfate wet deposition. Neglect of the ice phase when considering the chemistry in continental nonpolluted and continental polluted clouds may lead to overestimates of about 112%–130% of the total sulfur mass removed by wet deposition. The assumption of Henry's law equilibrium for those types of clouds gives an overestimation of about 100%–120%, respectively. PACS Nos.: 51.10.+y, 92.60.Sz

scholarly journals The influence of cloud chemistry on HO<sub>x</sub> and NO<sub>x</sub> in the moderately polluted marine boundary layer: a 1-D modelling study

2002 ◽  
Vol 2 (1) ◽  
pp. 39-54 ◽  
Author(s):  
J. E. Williams ◽  
F. J. Dentener ◽  
A. R. van den Berg
Keyword(s):  
Boundary Layer ◽  
Gas Phase ◽  
Marine Boundary Layer ◽  
Phase Transfer ◽  
Cloud Model ◽  
Chemical Mechanism ◽  
Cloud Chemistry ◽  
Marine Stratocumulus ◽  
The Impact ◽  
Heterogeneous Source

Abstract. A 1-D marine stratocumulus cloud model has been supplemented with a comprehensive and up-to-date aqueous phase chemical mechanism for the purpose of assessing the impact that the presence of clouds has on gas phaseHOx, NOx and O3 budgets in the marine boundary layer. The simulations presented here indicate that cloud may act as a heterogeneous source of HONOg. The conversion of HNO4(g) at moderate pH (~ 4.5) is responsible for this, and, to a lesser extent, the photolysis of nitrate (NO3-). The effect of introducing deliquescent aerosol on the simulated increase of HONOg is negligible. The most important consequences of this elevation in HONOg are that, in the presence of cloud, gas phase concentrations of NOx species increase by a factor of 2, which minimises the simulated decrease in O3(g), and results in a regeneration of OHg. This partly compensates for the removal of OHg by direct phase transfer into the cloud and may have important implications regarding the oxidising capacity of the marine boundary layer.

scholarly journals Cloud-scale model intercomparison of chemical constituent transport in deep convection

2007 ◽  
Vol 7 (18) ◽  
pp. 4709-4731 ◽  
Author(s):  
M. C. Barth ◽  
S.-W. Kim ◽  
C. Wang ◽  
K. E. Pickering ◽  
L. E. Ott ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Chemical Reactivity ◽  
Chemical Constituents ◽  
Deep Convection ◽  
Convective Transport ◽  
Scale Model ◽  
Cloud Chemistry ◽  
Mixing Ratios ◽  
The Impact

Abstract. Transport and scavenging of chemical constituents in deep convection is important to understanding the composition of the troposphere and therefore chemistry-climate and air quality issues. High resolution cloud chemistry models have been shown to represent convective processing of trace gases quite well. To improve the representation of sub-grid convective transport and wet deposition in large-scale models, general characteristics, such as species mass flux, from the high resolution cloud chemistry models can be used. However, it is important to understand how these models behave when simulating the same storm. The intercomparison described here examines transport of six species. CO and O3, which are primarily transported, show good agreement among models and compare well with observations. Models that included lightning production of NOx reasonably predict NOx mixing ratios in the anvil compared with observations, but the NOx variability is much larger than that seen for CO and O3. Predicted anvil mixing ratios of the soluble species, HNO3, H2O2, and CH2O, exhibit significant differences among models, attributed to different schemes in these models of cloud processing including the role of the ice phase, the impact of cloud-modified photolysis rates on the chemistry, and the representation of the species chemical reactivity. The lack of measurements of these species in the convective outflow region does not allow us to evaluate the model results with observations.

Tropospheric ozone chemistry. The impact of cloud chemistry

1993 ◽  
Vol 16 (2) ◽  
pp. 99-122 ◽  
Author(s):  
Jan E. Jonson ◽  
Ivar S. A. Isaksen
Keyword(s):  
Tropospheric Ozone ◽  
Cloud Chemistry ◽  
The Impact
Sign in / Sign up

Export Citation Format

Share Document