scholarly journals Global and regional effects of the photochemistry of CH<sub>3</sub>O<sub>2</sub>NO<sub>2</sub>: evidence from ARCTAS

2011 ◽  
Vol 11 (1) ◽  
pp. 2233-2262
Author(s):  
E. C. Browne ◽  
A. E. Perring ◽  
P. J. Wooldridge ◽  
E. Apel ◽  
S. R. Hall ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Biomass Burning ◽  
Low Temperatures ◽  
Transport Model ◽  
Chemical Transport ◽  
Chemical Transport Model ◽  
Upper Troposphere ◽  
Regional Effects ◽  
Global Chemical Transport Model ◽  
Lightning Nox

Abstract. Using measurements from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) experiment, we show that methyl peroxy nitrate (CH3O2NO2) is present in concentrations of ~5–15 pptv in the springtime arctic upper troposphere. We investigate the regional and global effects of CH3O2NO2 by including its chemistry in the GEOS-CHEM 3-D global chemical transport model. We find that at temperatures below 240 K inclusion of CH3O2NO2 chemistry results in decreases of up to ~20% in NOx, ~20% in N2O5, ~5% in HNO3, ~2% in ozone, and increases in methyl hydrogen peroxide of up to ~14%. Larger changes are observed in biomass burning plumes lofted to high altitude. Additionally, by sequestering NOx at low temperatures, CH3O2NO2 decreases the cycling of HO2 to OH, resulting in a larger upper tropospheric HO2 to OH ratio. These results may impact some estimates of lightning NOx sources as well as help explain differences between models and measurements of upper tropospheric composition.

scholarly journals Global and regional effects of the photochemistry of CH<sub>3</sub>O<sub>2</sub>NO<sub>2</sub>: evidence from ARCTAS

2011 ◽  
Vol 11 (9) ◽  
pp. 4209-4219 ◽  
Author(s):  
E. C. Browne ◽  
A. E. Perring ◽  
P. J. Wooldridge ◽  
E. Apel ◽  
S. R. Hall ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Biomass Burning ◽  
Low Temperatures ◽  
Transport Model ◽  
Chemical Transport ◽  
Chemical Transport Model ◽  
Upper Troposphere ◽  
Regional Effects ◽  
Global Chemical Transport Model ◽  
Lightning Nox

Abstract. Using measurements from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) experiment, we show that methyl peroxy nitrate (CH3O2NO2) is present in concentrations of ~5–15 pptv in the springtime arctic upper troposphere. We investigate the regional and global effects of CH3O2NO2 by including its chemistry in the GEOS-Chem 3-D global chemical transport model. We find that at temperatures below 240 K inclusion of CH3O2NO2 chemistry results in decreases of up to ~20 % in NOx, ~20 % in N2O5, ~5 % in HNO3, ~2 % in ozone, and increases in methyl hydrogen peroxide of up to ~14 %. Larger changes are observed in biomass burning plumes lofted to high altitude. Additionally, by sequestering NOx at low temperatures, CH3O2NO2 decreases the cycling of HO2 to OH, resulting in a larger upper tropospheric HO2 to OH ratio. These results may impact some estimates of lightning NOx sources as well as help explain differences between models and measurements of upper tropospheric composition.

scholarly journals Characteristics of intercontinental transport of tropospheric ozone from Africa to Asia

2017 ◽  
Author(s):  
Han Han ◽  
Jane Liu ◽  
Huiling Yuan ◽  
Ye Zhu ◽  
Yue Wu ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Transport Model ◽  
Chemical Transport ◽  
Early Spring ◽  
Boreal Summer ◽  
Boreal Winter ◽  
Chemical Transport Model ◽  
Upper Troposphere ◽  
Intercontinental Transport ◽  
Global Chemical Transport Model

Abstract. Based on 20-year simulations using a global chemical transport model, GEOS-Chem, and a trajectory model, HYSPLIT, the transport of ozone produced in the African troposphere to Asia is investigated. The study shows that the influence of African ozone on Asia varies largely in time and space. In the middle and upper troposphere, the inflow of African ozone to Asia peaks around 25° N, being the largest in boreal winter and early spring (> 10 ppbv) and the lowest in boreal summer (

High resolution Aerosol Radiative Effects over Europe using detailed optical properties from the Chemical Transport Model PMCAMx

2020 ◽  
Author(s):  
Marios Bruno Korras Carraca ◽  
Dimitris Manetas ◽  
David Patoulias ◽  
Spyros Pandis ◽  
Nikolaos Hatzianastassiou ◽  
...  
Keyword(s):  
Optical Properties ◽  
Temporal Resolution ◽  
Biomass Burning ◽  
Transport Model ◽  
Aerosol Particles ◽  
Chemical Transport ◽  
Chemical Transport Model ◽  
Aerosol Optical Properties ◽  
The Earth ◽  
Spatio Temporal

&lt;p&gt;Natural and anthropogenic aerosol particles are major drivers of the Earth&amp;#8217;s radiation budget, which they affect directly (through scattering and absorption) and indirectly (through modification of cloud scattering and precipitation properties), while they semi-directly influence atmospheric stability and convection, mainly through modification of solar radiation absorption by the atmosphere. Despite the important climatic role of aerosols, large uncertainties in their radiative effects remain due to limited knowledge of the aerosol spatio-temporal distribution and physico-chemical properties. The interaction of aerosols with radiation is strongly dependent on their optical properties, which in turn are controlled by the particles&amp;#8217; size distribution, shape, chemical composition and mixing state. In order to accurately estimate the magnitude of the aerosol direct radiative effect (DRE), detailed knowledge of their optical properties with high spatial and temporal resolution is required.&lt;/p&gt;&lt;p&gt;The European continent is a region of particular interest for studying atmospheric aerosol effects, because of the presence of&amp;#160; numerous and varying sources of particles and their precursors, such as industries, large urban centers and biomass burning, especially when combined with high levels of solar insolation during summer. In this study, the aerosol DRE over Europe is examined using the FORTH deterministic spectral radiative transfer model (RTM) and aerosol data from the chemical transport model PMCAMx. Chemically and size resolved aerosol concentrations predicted by PMCAMx are combined with a Mie model to calculate key aerosol optical properties (i.e. vertically resolved aerosol optical depth, single scattering albedo and asymmetry parameter) that are necessary to compute aerosol DRE using the RTM. The Mie model takes into account concentrations of organics, black carbon, sulfate, nitrate, ammonium, chlorine, sodium, water, and crustal material, and calculates aerosol optical properties assuming that the aerosol particles of the same size are internally mixed. The DRE is estimated at the Earth&amp;#8217;s surface, within the atmospheric column and at the top of the atmosphere (TOA), at high spatial and temporal resolution (36 &amp;#215; 36 km grids, 27 vertical layers, hourly), during June and July 2012.&lt;/p&gt;&lt;p&gt;Initial modelling results reveal that DREs exhibit significant spatio-temporal variability, due to the heterogeneity of source emissions rates, mostly with regard to wildfires, and the varying synoptic conditions. Emphasis is thus given to biomass burning aerosols, which are among the most significant radiative forcing agents in Europe during summer. Their relative forcing is computed by performing model computations with and without biomass burning emissions.&lt;/p&gt;

scholarly journals Source attribution of Arctic black carbon constrained by aircraft and surface measurements

2017 ◽  
Vol 17 (19) ◽  
pp. 11971-11989 ◽  
Author(s):  
Jun-Wei Xu ◽  
Randall V. Martin ◽  
Andrew Morrow ◽  
Sangeeta Sharma ◽  
Lin Huang ◽  
...  
Keyword(s):  
North America ◽  
Biomass Burning ◽  
Western Siberia ◽  
Transport Model ◽  
Chemical Transport ◽  
The Arctic ◽  
Anthropogenic Emissions ◽  
Chemical Transport Model ◽  
Northern Asia ◽  
Airborne Measurements

Abstract. Black carbon (BC) contributes to Arctic warming, yet sources of Arctic BC and their geographic contributions remain uncertain. We interpret a series of recent airborne (NETCARE 2015; PAMARCMiP 2009 and 2011 campaigns) and ground-based measurements (at Alert, Barrow and Ny-Ålesund) from multiple methods (thermal, laser incandescence and light absorption) with the GEOS-Chem global chemical transport model and its adjoint to attribute the sources of Arctic BC. This is the first comparison with a chemical transport model of refractory BC (rBC) measurements at Alert. The springtime airborne measurements performed by the NETCARE campaign in 2015 and the PAMARCMiP campaigns in 2009 and 2011 offer BC vertical profiles extending to above 6 km across the Arctic and include profiles above Arctic ground monitoring stations. Our simulations with the addition of seasonally varying domestic heating and of gas flaring emissions are consistent with ground-based measurements of BC concentrations at Alert and Barrow in winter and spring (rRMSE  < 13 %) and with airborne measurements of the BC vertical profile across the Arctic (rRMSE  = 17 %) except for an underestimation in the middle troposphere (500–700 hPa).Sensitivity simulations suggest that anthropogenic emissions in eastern and southern Asia have the largest effect on the Arctic BC column burden both in spring (56 %) and annually (37 %), with the largest contribution in the middle troposphere (400–700 hPa). Anthropogenic emissions from northern Asia contribute considerable BC (27 % in spring and 43 % annually) to the lower troposphere (below 900 hPa). Biomass burning contributes 20 % to the Arctic BC column annually.At the Arctic surface, anthropogenic emissions from northern Asia (40–45 %) and eastern and southern Asia (20–40 %) are the largest BC contributors in winter and spring, followed by Europe (16–36 %). Biomass burning from North America is the most important contributor to all stations in summer, especially at Barrow.Our adjoint simulations indicate pronounced spatial heterogeneity in the contribution of emissions to the Arctic BC column concentrations, with noteworthy contributions from emissions in eastern China (15 %) and western Siberia (6.5 %). Although uncertain, gas flaring emissions from oilfields in western Siberia could have a striking impact (13 %) on Arctic BC loadings in January, comparable to the total influence of continental Europe and North America (6.5 % each in January). Emissions from as far as the Indo-Gangetic Plain could have a substantial influence (6.3 % annually) on Arctic BC as well.

scholarly journals Implementation and evaluation of an array of chemical solvers in a global chemical transport model

2009 ◽  
Vol 2 (1) ◽  
pp. 185-207 ◽  
Author(s):  
P. Eller ◽  
K. Singh ◽  
A. Sandu ◽  
K. Bowman ◽  
D. K. Henze ◽  
...  
Keyword(s):  
Transport Model ◽  
Chemical Transport ◽  
Chemical Mechanism ◽  
Chemical Transport Model ◽  
Simulation Code ◽  
Programming Effort ◽  
Efficient Code ◽  
Global Chemical Transport Model ◽  
And Performance ◽  
Continuous Adjoint

Abstract. This paper discusses the implementation and performance of an array of gas-phase chemistry solvers for the state-of-the-science GEOS-Chem global chemical transport model. The implementation is based on the Kinetic PreProcessor (KPP). Two perl parsers automatically generate the needed interfaces between GEOS-Chem and KPP, and allow access to the chemical simulation code without any additional programming effort. This work illustrates the potential of KPP to positively impact global chemical transport modeling by providing additional functionality as follows. (1) The user can select a highly efficient numerical integration method from an array of solvers available in the KPP library. (2) KPP offers extreme flexibility for studies that involve changing the chemical mechanism (e.g., a set of additional reactions is automatically translated into efficient code and incorporated into a modified global model). (3) This work provides immediate access to tangent linear, continuous adjoint, and discrete adjoint chemical models, with applications to sensitivity analysis and data assimilation.

scholarly journals Biomass burning influence on high latitude tropospheric ozone and reactive nitrogen in summer 2008: a multi-model analysis based on POLMIP simulations

2014 ◽  
Vol 14 (17) ◽  
pp. 24573-24621 ◽  
Author(s):  
S. R. Arnold ◽  
L. K. Emmons ◽  
S. A. Monks ◽  
K. S. Law ◽  
D. A. Ridley ◽  
...  
Keyword(s):  
Biomass Burning ◽  
High Latitude ◽  
Tropospheric Ozone ◽  
Transport Model ◽  
Chemical Transport ◽  
Ozone Production ◽  
The Arctic ◽  
Vertical Position ◽  
Chemical Transport Model ◽  
Fire Emissions

Abstract. We have evaluated tropospheric ozone enhancement in air dominated by biomass burning emissions at high laititudes (> 50˚ N) in July 2008, using 10 global chemical transport model simulations from the POLMIP multi-model comparison exercise. In model air masses dominated by fire emissions, Δ O3/ΔCO values ranged between 0.039 and 0.196 ppbv ppbv−1 (mean: 0.113 ppbv ppbv−1) in freshly fire-influenced air, and between 0.140 and 0.261 ppbv ppbv−1 (mean: 0.193 ppbv) in more aged fire-influenced air. These values are in broad agreement with the range of observational estimates from the literature. Model ΔPAN/ΔCO enhancement ratios show distinct groupings according to the meteorological data used to drive the models. ECMWF-forced models produce larger ΔPAN/ΔCO values (4.44–6.28 pptv ppbv−1) than GEOS5-forced models (2.02–3.02 pptv ppbv−1), which we show is likely linked to differences efficiency of vertical transport during poleward export from mid-latitude source regions. Simulations of a large plume of biomass burning and anthropogenic emissions exported from Asia towards the Arctic using a Lagrangian chemical transport model show that 4 day net ozone change in the plume is sensitive to differences in plume chemical composition and plume vertical position among the POLMIP models. In particular, Arctic ozone evolution in the plume is highly sensitive to initial concentrations of PAN, as well as oxygenated VOCs (acetone, acetaldehyde), due to their role in producing the peroxyacetyl radical PAN precursor. Vertical displacement is also important due to its effects on the stability of PAN, and subsequent effect on NOx abundance. In plumes where net ozone production is limited, we find that the lifetime of ozone in the plume is sensitive to hydrogen peroxide loading, due to the production of HO2 from peroxide photolysis, and the key role of HO2 + O3 in controlling ozone loss. Overall, our results suggest that emissions from biomass burning lead to large-scale photochemical enhancement in high latitude tropospheric ozone during summer.

scholarly journals Combined assimilation of IASI and MLS observations to constrain tropospheric and stratospheric ozone in a global chemical transport model

2013 ◽  
Vol 13 (8) ◽  
pp. 21455-21505
Author(s):  
E. Emili ◽  
B. Barret ◽  
S. Massart ◽  
E. Le Flochmoen ◽  
A. Piacentini ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Radiative Forcing ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Chemical Transport ◽  
Free Troposphere ◽  
Chemical Transport Model ◽  
Ozone Monitoring Instrument ◽  
Global Chemical Transport Model ◽  
The Impact

Abstract. Accurate and temporally resolved fields of free-troposphere ozone are of major importance to quantify the intercontinental transport of pollution and the ozone radiative forcing. In this study we examine the impact of assimilating ozone observations from the Microwave Limb Sounder (MLS) and the Infrared Atmospheric Sounding Interferometer (IASI) in a global chemical transport model (MOdèle de Chimie Atmosphérique à Grande Échelle, MOCAGE). The assimilation of the two instruments is performed by means of a variational algorithm (4-D-VAR) and allows to constrain stratospheric and tropospheric ozone simultaneously. The analysis is first computed for the months of August and November 2008 and validated against ozone-sondes measurements to verify the presence of observations and model biases. It is found that the IASI Tropospheric Ozone Column (TOC, 1000–225 hPa) should be bias-corrected prior to assimilation and MLS lowermost level (215 hPa) excluded from the analysis. Furthermore, a longer analysis of 6 months (July–August 2008) showed that the combined assimilation of MLS and IASI is able to globally reduce the uncertainty (Root Mean Square Error, RMSE) of the modeled ozone columns from 30% to 15% in the Upper-Troposphere/Lower-Stratosphere (UTLS, 70–225 hPa) and from 25% to 20% in the free troposphere. The positive effect of assimilating IASI tropospheric observations is very significant at low latitudes (30° S–30° N), whereas it is not demonstrated at higher latitudes. Results are confirmed by a comparison with additional ozone datasets like the Measurements of OZone and wAter vapour by aIrbus in-service airCraft (MOZAIC) data, the Ozone Monitoring Instrument (OMI) total ozone columns and several high-altitude surface measurements. Finally, the analysis is found to be little sensitive to the assimilation parameters and the model chemical scheme, due to the high frequency of satellite observations compared to the average life-time of free-troposphere/low-stratosphere ozone.

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