Receptor modelling of fine particles in southern England using CMB including comparison with AMS-PMF factors
Summary: Breathing particles from polluted air is known to cause increased health complaints and higher death rates. Airborne particles come from a range of sources; in order to implement cost-effective control measures, it is necessary to understand the amount contributed by each. In this paper, two advanced procedures for estimating the contributions of particle sources in London are compared with one another, revealing a wide range of sources including traffic, woodsmoke and cooking particles.
Dependence of the vertical distribution of bromine monoxide in the lower troposphere on meteorological factors such as wind speed and stability
Summary: We developed methods to measure the vertical distribution of bromine monoxide, a gas that oxidizes pollutants, above sea ice based upon MAX-DOAS observations from Barrow, Alaska, and find that atmospheric stability exerts a strong control on BrO's vertical distribution. Specifically, more stable (temperature inversion) situations result in BrO being closer to the ground while more neutral (not inverted) atmospheres allow BrO to ascend further aloft and grow to larger column abundance.
Greenhouse gas network design using backward Lagrangian particle dispersion modelling – Part 2: Sensitivity analyses and South African test case
Summary: This study aims to provide an optimal network design for the placement of new atmospheric monitoring stations around South Africa, to best estimate the emission and uptake of carbon dioxide fluxes due to both anthropogenic and natural sources. In addition, a sensitivity analysis was performed on the impact that certain parameters would have on the final network solution, considering the inverse modelling framework, the transport model and the use of a different optimisation routine.
Contribution of liquid, NAT and ice particles to chlorine activation and ozone depletion in Antarctic winter and spring
Summary: We use multi-year simulations of the chemistry--climate model EMAC to investigate
the impact that the various types of PSCs have on Antarctic chlorine activation and ozone loss. Heterogeneous chemistry on liquid particles is responsible for more than 90% of the ozone depletion in Antarctic spring in the model simulations. In high southern latitudes, heterogeneous chemistry on ice particles causes only up to 5 DU of additional ozone depletion and chemistry on NAT particles less than 0.5 DU.
Sources of humic-like substances in the Pearl River Delta, China: positive matrix factorization analysis of PM2.5 major components and source markers
Summary: Humic-like substances (HULIS), the hydrophobic part of water soluble organic material, account for ~10% of PM2.5 mass in the Pearl River Delta, China. Source analysis using PM2.5 chemical composition data revealed that secondary formation process, biomass burning, and residual oil combustion from shipping as significant sources of HULIS. Vehicle emissions contributed little to HULIS. Primary sources of HULIS appeared to be linked to inefficient combustion.
Investigation of secondary formation of formic acid: urban environment vs. oil and gas producing region
Summary: In this work, secondary formation of formic acid at an urban site and a site in an oil and gas production region is studied. We investigated various gas phase formation pathways of formic acid, including those recently proposed, using a box model. The contributions from aerosol-related processes, fog events and air-snow exchange to formic acid are also quantified.
B. Yuan, P. R. Veres, C. Warneke, J. M. Roberts, J. B. Gilman, A. Koss, P. M. Edwards, M. Graus, W. C. Kuster, S.-M. Li, R. J. Wild, S. S. Brown, W. P. Dubé, B. M. Lerner, E. J. Williams, J. E. Johnson, P. K. Quinn, T. S. Bates, B. Lefer, P. L. Hayes, J. L. Jimenez, R. J. Weber, R. Zamora, B. Ervens, D. B. Millet, B. Rappenglück, and J. A. de Gouw Atmos. Chem. Phys., 15, 1975-1993, 2015 AbstractFinal Revised Paper (PDF, 1831 KB)Supplement (1450 KB)Discussion Paper (ACPD)Special Issue
24 Feb 2015
Effect of biomass burning over the western North Pacific Rim: wintertime maxima of anhydrosugars in ambient aerosols from Okinawa
Summary: Using levoglucosan as a biomass burning tracer, influence of biomass burning on the air quality of Okinawa Island in the western North Pacific Rim was evaluated. High levels of levoglucosan were found in the atmospheric aerosols during winter probably due to the open burning and domestic heating and cooking in north/northeast China, Mongolia and Russia, together with enhanced continental outflow.
An estimation of the 18O / 16O ratio of UT/LMS ozone based on artefact CO in air sampled during CARIBIC flights
Summary: We present observational data on δ18O(O3) from the UT/LMS, the region to date not covered by the ozone isotope composition measurements. It is to bridge the gap between the tropospheric (mostly surface) and stratospheric measurement data.
We demonstrate an approach suitable for isotope mass-balance calculations (“Keeling plot”) in intricate cases, i.e. admixing of the (unknown) source in question to the reservoirs with (unknown) variable starting compositions.
Identification and quantification of gaseous organic compounds emitted from biomass burning using two-dimensional gas chromatography–time-of-flight mass spectrometry
Summary: This work represents the first application of two-dimensional gas chromatography to broadly characterize the gas-phase emissions of biomass burning, including comparisons among the emissions from burns of selected conifer, grass, crop residue, and peat fuel types. In these smoke samples, over 700 compounds were detected, which are discussed in the context of potential secondary organic aerosol formation.
Mixing state of carbonaceous aerosol in an urban environment: single particle characterization using the soot particle aerosol mass spectrometer (SP-AMS)
Summary: Understanding the impact of black carbon (BC) particles on human health and radiative forcing requires knowledge of the BC mixing state. This work investigates the mixing state of BC and other aerosol species in a typical urban area using a single particle mass spectrometry technique. Our results provide quantitative insight into the physical and chemical nature of BC-containing particles near emission and can be used as a basis for our developing understanding of BC evolution in the atmosphere.
Polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and chlorinated pesticides in background air in central Europe – investigating parameters affecting wet scavenging of polycyclic aromatic hydrocarbons
Strong atmospheric new particle formation in winter in urban Shanghai, China
S. Xiao, M. Y. Wang, L. Yao, M. Kulmala, B. Zhou, X. Yang, J. M. Chen, D. F. Wang, Q. Y. Fu, D. R. Worsnop, and L. Wang Atmos. Chem. Phys., 15, 1769-1781, 2015 AbstractFinal Revised Paper (PDF, 1562 KB)Discussion Paper (ACPD)
19 Feb 2015
Observations of the temporal variability in aerosol properties and their relationships to meteorology in the summer monsoonal South China Sea/East Sea: the scale-dependent role of monsoonal flows, the Madden–Julian Oscillation, tropical cyclones, squall lines and cold pools
Summary: This paper reports on the first measurements of aerosol particles embedded in the convectively active southwest monsoonal flow of the South China Sea. The paper describes the research cruise and discusses how variability in aerosol characteristics relates to regional meteorological phenomena such as and the Madden Julian Oscillation, tropical cyclones, squall lines and the monsoonal flow itself. Of special interest is how aerosol transport relates to meteorological drivers of convective activity.
J. S. Reid, N. D. Lagrosas, H. H. Jonsson, E. A. Reid, W. R. Sessions, J. B. Simpas, S. N. Uy, T. J. Boyd, S. A. Atwood, D. R. Blake, J. R. Campbell, S. S. Cliff, B. N. Holben, R. E. Holz, E. J. Hyer, P. Lynch, S. Meinardi, D. J. Posselt, K. A. Richardson, S. V. Salinas, A. Smirnov, Q. Wang, L. Yu, and J. Zhang Atmos. Chem. Phys., 15, 1745-1768, 2015 AbstractFinal Revised Paper (PDF, 9131 KB)Discussion Paper (ACPD)
19 Feb 2015
The role of aerosol in altering North Atlantic atmospheric circulation in winter and its impact on air quality
Summary: our study suggests that future aerosol abatement may be the primary driver of increased blocking events over the western Mediterranean. This modification of the atmospheric circulation over the Euro-Atlantic sector leads to more stagnant weather conditions that favour air pollutant accumulation especially in the western Mediterranean sector. Changes in atmospheric circulation should therefore be included in future air pollution mitigation assessments.
An attempt at estimating Paris area CO2 emissions from atmospheric concentration measurements
F. M. Bréon, G. Broquet, V. Puygrenier, F. Chevallier, I. Xueref-Remy, M. Ramonet, E. Dieudonné, M. Lopez, M. Schmidt, O. Perrussel, and P. Ciais Atmos. Chem. Phys., 15, 1707-1724, 2015 AbstractFinal Revised Paper (PDF, 1884 KB)Supplement (657 KB)Discussion Paper (ACPD)
18 Feb 2015
Source sector and region contributions to BC and PM2.5 in Central Asia
Summary: This study presents a regional-scale modeling analysis of aerosols in the Central Asia region including detailed characterization of seasonal source region and sector contributions along with the predicted changes in distribution of aerosols using 2030 future emission scenarios. The influence of long transport and impact of varied emission sources including dust, biomass burning, and anthropogenic sources on the regional aerosol distributions and the associated transport pathways are discussed.
S. Kulkarni, N. Sobhani, J. P. Miller-Schulze, M. M. Shafer, J. J. Schauer, P. A. Solomon, P. E. Saide, S. N. Spak, Y. F. Cheng, H. A. C. Denier van der Gon, Z. Lu, D. G. Streets, G. Janssens-Maenhout, C. Wiedinmyer, J. Lantz, M. Artamonova, B. Chen, S. Imashev, L. Sverdlik, J. T. Deminter, B. Adhikary, A. D'Allura, C. Wei, and G. R. Carmichael Atmos. Chem. Phys., 15, 1683-1705, 2015 AbstractFinal Revised Paper (PDF, 11124 KB)Supplement (5576 KB)Discussion Paper (ACPD)
18 Feb 2015
Prediction of gas/particle partitioning of polybrominated diphenyl ethers (PBDEs) in global air: A theoretical study
Summary: Gas/particle partitioning for polybrominated diphenyl ethers (PBDEs) in global air was investigated and an equation to predict the partition coefficients under steady state was developed, indicating that equilibrium is a special case of steady state when the non-equilibrium factor can be ignored. The results of the equation matched the worldwide monitoring data well, showing its superiority to the equilibrium-state-based equation that has been used in recent decades.
Technical Note: On the possibly missing mechanism of 15 μm emission in the mesosphere–lower thermosphere (MLT)
Summary: This paper investigates the discrepancy between the rate coefficients for the deactivation of the bending mode of CO2 by atomic oxygen, a process of great importance in the energy budget of the mesosphere and the lower thermosphere, measured in the laboratory and arrived at by space-based measurements. It is concluded that super-thermal rotational levels of N2, produced by the impact of hot O atoms or by N + NO reaction, have the potential to provide the unknown mechanism.
Characterization of forest fire smoke event near Washington, DC in summer 2013 with multi-wavelength lidar
Summary: The multi-wavelength lidar technique was applied to the study of a smoke event near Washington, DC on 26-28 August 2013. Satellite observations combined with transport model predictions imply that the smoke plume originated mainly from Wyoming/Idaho forest fires. The NASA GSFC multi-wavelength Mie-Raman lidar was used to profile the smoke particle parameters such as volume density, effective radius and the real part of the refractive index.
I. Veselovskii, D. N Whiteman, M. Korenskiy, A. Suvorina, A. Kolgotin, A. Lyapustin, Y. Wang, M. Chin, H. Bian, T. L. Kucsera, D. Pérez-Ramírez, and B. Holben Atmos. Chem. Phys., 15, 1647-1660, 2015 AbstractFinal Revised Paper (PDF, 6066 KB)Discussion Paper (ACPD)
17 Feb 2015
Aged boreal biomass-burning aerosol size distributions from BORTAS 2011
Deposition-mode ice nucleation reexamined at temperatures below 200 K
Summary: We present new observations of ice nucleation on substrate surfaces that affirm the ``puzzle'' of very high supersaturations required for nucleation from the vapor phase. To explain the observations, the kinetics and thermodynamics of nucleation theory are explored. The results explicitly connect the nucleation to the substrate material's surface binding energy and demonstrate that an improved fundamental understanding must include a strict understanding of the relevant microphysics.
Influence of satellite-derived photolysis rates and NOx emissions on Texas ozone modeling
Summary: A joint application of multiple satellite-derived model inputs to improve Texas O3 SIP modeling is demonstrated in this study. The GOES-retrieved clouds are applied to correct the modeled photolysis rates, and the DKF inversion approach is incorporated into the CAMx-DDM model to adjust NOx emissions using OMI NO2. Using both GOES-derived photolysis rates and OMI-constrained NOx emissions together improves O3 simulations and makes O3 more sensitive to NOx emissions in the O3 non-attainment areas.
Modelling street level PM10 concentrations across Europe: source apportionment and possible futures
Summary: We describe the multi-stage approach applied in the GAINS model to assess compliance with PM10 limit values at more than 1850 individual air quality monitoring stations in Europe. We analyse source contributions to ambient concentrations and the implications of future policy choices on air quality for 2030. While current legislation does not solve compliance issues, problems are largely eliminated by EU-wide adoption of the best available emission control technology.
G. Kiesewetter, J. Borken-Kleefeld, W. Schöpp, C. Heyes, P. Thunis, B. Bessagnet, E. Terrenoire, H. Fagerli, A. Nyiri, and M. Amann Atmos. Chem. Phys., 15, 1539-1553, 2015 AbstractFinal Revised Paper (PDF, 1660 KB)Discussion Paper (ACPD)
13 Feb 2015
Sensitivity of top-down CO source estimates to the modeled vertical structure in atmospheric CO
Summary: Using MOPITT (version 5) tropospheric profile and surface layer retrievals, we constrain global CO emissions in the period of June 2004 – May 2005. The inversions suggest a reduction in CO emission in the tropics and an increase in emissions at middle and high latitudes. The results demonstrate that the use of the surface layer retrievals from MOPITT can significantly mitigate the potential impacts of model bias in OH and long-range transport on CO emission estimates.
Effects of pre-existing ice crystals on cirrus clouds and comparison between different ice nucleation parameterizations with the Community Atmosphere Model (CAM5)
Summary: The ice nucleation scheme in the Community Atmosphere Model (CAM5) was improved by considering the effects of pre-existing ice crystals and some other modifications. Subsequently, the comparison between different ice nucleation parameterizations is investigated. Experiment using the ice nucleation parameterization of Kärcher et al. (2006) predicts a much smaller anthropogenic aerosol indirect forcing than that using the parameterizations of Liu and Penner (2005) and Barahona and Nenes (2009).
Corrigendum to "Size-resolved observations of refractory black carbon particles in cloud droplets at a marine boundary layer site" published in Atmos. Chem. Phys., 15, 1367–1383, 2015
J. C. Schroder, S. J. Hanna, R. L. Modini, A. L. Corrigan, S. M. Kreidenweis, A. M. Macdonald, K. J. Noone, L. M. Russell, W. R. Leaitch, and A. K. Bertram Atmos. Chem. Phys., 15, 1487-1487, 2015 AbstractFinal Revised Paper (PDF, 18 KB)Corresponding Article
11 Feb 2015
Intercomparing different devices for the investigation of ice nucleating particles using Snomax® as test substance
Summary: Immersion freezing measurements from seven different measurement techniques were intercompared using a biological ice nucleating material from bacteria. Although different techniques examined differently concentrated droplets, it was possible to find a uniform description, which showed that results from all experiments were generally in good agreement and were also in agreement with parameterizations published earlier in literature.
H. Wex, S. Augustin-Bauditz, Y. Boose, C. Budke, J. Curtius, K. Diehl, A. Dreyer, F. Frank, S. Hartmann, N. Hiranuma, E. Jantsch, Z. A. Kanji, A. Kiselev, T. Koop, O. Möhler, D. Niedermeier, B. Nillius, M. Rösch, D. Rose, C. Schmidt, I. Steinke, and F. Stratmann Atmos. Chem. Phys., 15, 1463-1485, 2015 AbstractFinal Revised Paper (PDF, 1112 KB)Discussion Paper (ACPD)Special Issue
10 Feb 2015
Evaluation of black carbon emission inventories using a Lagrangian dispersion model – a case study over southern India
Summary: Emission inventories are a key component of simulating past, present and future climate. In this article we have evaluated three black carbon emission inventories for emissions of India using observations made from a strategic location. Annual average simulated black carbon concentration is found to be 35% to 60% lower than observed concentration because of underestimation of emissions of southern India in the inventories.
Scavenging ratios of polycyclic aromatic compounds in rain and snow in the Athabasca oil sands region
Summary: This study analyzed air and precipitation concentrations of 43 polycyclic aromatic compounds (PACs) collected in the Athabasca oil sands region. A database has been built for the parameter scavenging ratio, which is defined as the ratio of the concentration of PACs in precipitation to that in air. A better understanding of the potential differences between gas and particulate scavenging and between snow and rain scavenging has been achieved.
Annual cycles of organochlorine pesticide enantiomers in Arctic air suggest changing sources and pathways
Summary: Canadian Arctic air samples were analysed for enantiomers (mirror-image isomers) of pesticides α-hexachlorocyclohexane (α-HCH), trans-chlordane (TC) and cis-chlordane (CC). Annual cycles of enantiomer proportions suggested greater emission of microbially degraded residues from water and soil in warm vs. cold seasons. Enantiomer profiles may change in the future with rising contributions from secondary sources, monitoring them could increase the forensic capability in air monitoring programs.
Size-resolved observations of refractory black carbon particles in cloud droplets at a marine boundary layer site
J. C. Schroder, S. J. Hanna, R. L. Modini, A. L. Corrigan, S. M. Kreidenwies, A. M. Macdonald, K. J. Noone, L. M. Russell, W. R. Leaitch, and A. K. Bertram Atmos. Chem. Phys., 15, 1367-1383, 2015 Abstract
Notice on Corrigendum The requested paper has a corresponding Corrigendum published. Please read the
Corrigendum first before downloading the article.
Effects of molecular weight and temperature on liquid–liquid phase separation in particles containing organic species and inorganic salts
Summary: The first set of studies illustrates that the liquid/liquid phase separation relative humidity (SRH) does not depend strongly on molecular weight. The second set of studies shows that for most particle types and temperature range studied, SRH does not depend strongly on temperature. SRH did depend strongly on temperature for particles containing α,4-dihydroxy-3-methoxybenzeneacetic acid mixed with ammonium bisulfate due to a combination of low temperature and low water content.
Insights into characteristics, sources, and evolution of submicron aerosols during harvest seasons in the Yangtze River delta region, China
Summary: The chemical composition, sources, and evolution processes of PM1 were investigated with an Aerodyne ACSM during harvest seasons in the Yangtze River delta, China. Two biomass burning organic aerosol (BBOA) factors derived from PMF model were assessed. The oxidized BBOA contributes ~80% of the total BBOA loadings in the BB plumes. Evidence that BBOA may be oxidized to more aged and less volatile organics during the aging process was suggested.
MAX-DOAS tropospheric nitrogen dioxide column measurements compared with the Lotos-Euros air quality model
Summary: Ground-based remote sensing measurements of nitrogen dioxide are compared to the Lotos-Euros air quality (AQ) model. Measurements were taken in the Netherlands with a UV-Vis spectrometer which observes scattered sunlight under different elevation viewing angles. On average, a surprisingly good agreement is found. Perhaps most striking is the agreement between model and observations as a function of wind direction. This demonstrates the quality of the AQ model and underlying emission inventory.
Fossil vs. non-fossil sources of fine carbonaceous aerosols in four Chinese cities during the extreme winter haze episode of 2013
Summary: Source apportionment of fine carbonaceous aerosols using radiocarbon and other organic markers measurements during 2013 winter haze episodes was conducted at four megacities in China. Our results demonstrate that fossil emissions predominate EC with a mean contribution of 75±8%, whereas non-fossil sources account for 55±10% of OC; and the increment of TC on heavily polluted days was mainly driven by the increase of secondary OC from both fossil-fuel and non-fossil emissions.
Y.-L. Zhang, R.-J. Huang, I. El Haddad, K.-F. Ho, J.-J. Cao, Y. Han, P. Zotter, C. Bozzetti, K. R. Daellenbach, F. Canonaco, J. G. Slowik, G. Salazar, M. Schwikowski, J. Schnelle-Kreis, G. Abbaszade, R. Zimmermann, U. Baltensperger, A. S. H. Prévôt, and S. Szidat Atmos. Chem. Phys., 15, 1299-1312, 2015 AbstractFinal Revised Paper (PDF, 456 KB)Supplement (212 KB)Discussion Paper (ACPD)
06 Feb 2015
Evidence for an unidentified non-photochemical ground-level source of formaldehyde in the Po Valley with potential implications for ozone production
Summary: Using measurements acquired from a Zeppelin airship during the PEGASOS 2012 campaign, we show that VOC oxidation alone cannot account for the formaldehyde concentrations observed in the morning over rural Italy. Vertical profiles suggest a ground-level source of HCHO. Incorporating this additional HCHO source into a photochemical model increases calculated O3 production by as much as 12%.
J. Kaiser, G. M. Wolfe, B. Bohn, S. Broch, H. Fuchs, L. N. Ganzeveld, S. Gomm, R. Häseler, A. Hofzumahaus, F. Holland, J. Jäger, X. Li, I. Lohse, K. Lu, A. S. H. Prévôt, F. Rohrer, R. Wegener, R. Wolf, T. F. Mentel, A. Kiendler-Scharr, A. Wahner, and F. N. Keutsch Atmos. Chem. Phys., 15, 1289-1298, 2015 AbstractFinal Revised Paper (PDF, 454 KB)Supplement (212 KB)Discussion Paper (ACPD)Special Issue
06 Feb 2015
Evaluation of CALIOP 532 nm aerosol optical depth over opaque water clouds
Impact of updated traffic emissions on HONO mixing ratios simulated for urban site in Houston, Texas
Summary: Model simulations were performed with increased HONO emissions from mobile sources that reflect recent measurements at high-traffic urban sites. These higher emissions resulted in increased morning concentrations of HONO and OH. O3 concentrations were only marginally altered. Comparison with observed data shows that HONO morning peak concentrations are better predicted by the model when the higher emissions are utilized in the simulation.
On the relationship between open cellular convective cloud patterns and the spatial distribution of precipitation
Summary: Precipitation is necessary but insufficient for transformation to open cells from closed cells. The transformation to open cells occurs for sufficiently small droplet number concentration and/or large rain area. Both of these factors appear to be of similar importance. The distance selects the resulting state for rain regions that alone are too weak to initiate the transformation. The phase trajectory of the variance and mean cloud field properties follow one path.
Recent satellite-based trends of tropospheric nitrogen dioxide over large urban agglomerations worldwide
Summary: We use a homogeneous 10-year record of satellite data to study recent trends in NO2 over the world's major urban agglomerations. The results indicate distinct spatial patterns in trends, with moderate but consistent reductions in NO2 throughout most developed countries and rapid increases of up to 15 % per year over many sites in Asia, Africa, and South America. We also show links between urban NO2 trends and economic as well as demographic factors, and how the latter drive regional differences.
Carbonaceous aerosols recorded in a southeastern Tibetan glacier: analysis of temporal variations and model estimates of sources and radiative forcing
Summary: Carbonaceous aerosols recorded in a Tibetan glacier present a distinct seasonal dependence and an increasing trend after 1980, which has important implications for the accelerated glacier melting. We use a global aerosol--climate model to quantify the aerosol source--receptor relationships, showing that emissions in South Asia had the largest contribution. The emission inventories and historical fuel consumption in South Asia are consistent with our ice-core analysis and model results.
Use of a global model to understand speciated atmospheric mercury observations at five high-elevation sites
Summary: Speciated atmospheric Hg measurements from five high-elevation sites were compared with a global mercury model. The comparison confirmed that reactive mercury is formed in dry free tropospheric air from the oxidation of elemental Hg, more so in the summer than in other seasons. Simulations run with OH-O3 oxidation instead of the Br oxidation mechanism compared more closely with observations at desert sites, suggesting future simulations should include multiple reaction mechanisms simultaneously.
Influence of biomass burning plumes on HONO chemistry in eastern China
W. Nie, A. J. Ding, Y. N. Xie, Z. Xu, H. Mao, V.-M. Kerminen, L. F. Zheng, X. M. Qi, X. Huang, X.-Q. Yang, J. N. Sun, E. Herrmann, T. Petäjä, M. Kulmala, and C. B. Fu Atmos. Chem. Phys., 15, 1147-1159, 2015 AbstractFinal Revised Paper (PDF, 4468 KB)Discussion Paper (ACPD)
02 Feb 2015
Joint analysis of continental and regional background environments in the western Mediterranean: PM1 and PM10 concentrations and composition
Summary: The complete chemical compositions of atmospheric particulate matter (PM1 and PM10) from a continental (Montsec, 1570 m a.s.l.) and a regional (Montseny, 720 m a.s.l) background site in the western Mediterranean Basin were jointly studied for the first time over a relatively long-term period (January 2010-March 2013). Results revealed a) a high relevance of African dust transport and regional dust resuspension; b) low biomass burning contribution; and c) high organic matter contribution.
On the relationship between the scattering phase function of cirrus and the atmospheric state
Summary: The relationship between the shape of cirrus scattering phase functions and the atmospheric state is investigated using space-based multi-angle remote sensing measurements and high-resolution numerical weather prediction model output of the relative humidity field with respect to ice (RHi). It is found that on a pixel-by-pixel basis, the most featureless phase functions are generally associated with RHi>1, whilst for RHi<1, a unique model phase function could not be assigned to the pixel.
A regional carbon data assimilation system and its preliminary evaluation in East Asia
Summary: We associated the smoothing operator with the atmospheric transport model to constitute the persistence dynamical model to forecast the surface CO2 flux scaling factors for the purpose of resolving the "signal-to-noise" problem, as well as transporting the useful observed information onto the next assimilation cycle. Based on this improvement, a regional surface CO2 flux inversion system, CFI-CMAQ, has been developed. The OSSEs showed that the performance of CFI-CMAQ is effective and promising.
Inclusion of mountain-wave-induced cooling for the formation of PSCs over the Antarctic Peninsula in a chemistry–climate model
A. Orr, J. S. Hosking, L. Hoffmann, J. Keeble, S. M. Dean, H. K. Roscoe, N. L. Abraham, S. Vosper, and P. Braesicke Atmos. Chem. Phys., 15, 1071-1086, 2015 AbstractFinal Revised Paper (PDF, 7729 KB)Discussion Paper (ACPD)
30 Jan 2015
Detailed source term estimation of the atmospheric release for the Fukushima Daiichi Nuclear Power Station accident by coupling simulations of an atmospheric dispersion model with an improved deposition scheme and oceanic dispersion model
Summary: The detailed atmospheric releases during the Fukushima Daiichi Nuclear Power Station accident were estimated using a reverse estimation method with atmospheric and oceanic dispersion models. The major releases occurred on the afternoon of 12 March, midnight of 14 March, the morning and night of 15 March, and the morning of 16 March in 2011. Several atmospheric dispersion models with our new source term reproduced the local and regional patterns of I-131 and Cs-137 deposition and air dose rate.
Correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China
Summary: This paper is the first to report correlation slopes of GEM/CO, GEM/CO2, GEM/CH4, CH4/CO, CH4/CO2, and CO/CO2 for mainland China, South Asia, the Indochinese Peninsula, and Central Asia, and applied the values to estimate GEM emissions in the four source regions. The estimated Hg0 emissions for mainland China, South Asia, the Indochinese Peninsula, and Central Asia using GEM/CO and GEM/CO2 correlation slopes are in the ranges of 1071-1187, 340-470, 125, and 54-90t, respectively.
Secondary organic aerosol formation from hydroxyl radical oxidation and ozonolysis of monoterpenes
D. F. Zhao, M. Kaminski, P. Schlag, H. Fuchs, I.-H. Acir, B. Bohn, R. Häseler, A. Kiendler-Scharr, F. Rohrer, R. Tillmann, M. J. Wang, R. Wegener, J. Wildt, A. Wahner, and Th. F. Mentel Atmos. Chem. Phys., 15, 991-1012, 2015 AbstractFinal Revised Paper (PDF, 428 KB)Supplement (90 KB)Discussion Paper (ACPD)
28 Jan 2015
Influence of aerosol chemical composition on N2O5 uptake: airborne regional measurements in northwestern Europe
Summary: This paper used observations from a research aircraft flying around the UK to investigate how air pollution in north-western Europe can alter nighttime chemical reactions in the atmosphere. These chemical reactions can worsen air quality in the region, as well as influence regional climate change. Ammonium nitrate aerosol appears to play an important role. The paper indicates that representation of these chemical reactions is poorly represented in models used for air quality and climate.
Atmospheric wet and dry deposition of trace elements at 10 sites in Northern China
Summary: This paper presents the first concurrent measurements of wet and dry deposition of various trace elements in Northern China, covering an extensive area over 3 years in a global hotspot of air pollution. The unique field data can serve as a sound basis for the validation of regional emission inventories and biogeochemical or atmospheric chemistry models. The findings are very important for policy makers to create legislation to reduce the emissions and protect soil and water from air pollution.
Satellite observations of cirrus clouds in the Northern Hemisphere lowermost stratosphere
Summary: Here we present observations of the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) of cirrus cloud and water vapour in August 1997 in the upper troposphere and lower stratosphere (UTLS) region. The observations indicate a considerable flux of moisture from the upper tropical troposphere into the extra-tropical lowermost stratosphere (LMS), resulting in the occurrence of high-altitude optically thin cirrus clouds in the LMS.