Aerosol chemistry above an extended Archipelago of the Eastern Mediterranean basin during strong northern winds
Atmos. Chem. Phys. Discuss., 15, 9355-9403, doi:10.5194/acpd-15-9355-2015, 2015
Radiative forcing and climate response to projected 21st century aerosol decreases
Summary: Decreases in aerosols over the 21st century as projected by the Representative Concentration Pathways (RCPs) lead to increases up to 1 ºC in global temperature and up to 0.1 mm/day in global precipitation. In East Asia and other regions, future aerosol decreases could be responsible for 30-40% of total climate warming by 2100, even under the high greenhouse gas emissions scenario (RCP8.5). Radiative forcing and climate response to decreasing aerosols is largely similar in each of the RCPs.
Atmos. Chem. Phys. Discuss., 15, 9293-9353, doi:10.5194/acpd-15-9293-2015, 2015
Nonlinear response of modeled stratospheric ozone to changes in greenhouse gases and ozone depleting substances in the recent past
Summary: The attribution of stratospheric ozone (O3) loss in the recent past to increasing ozone depleting substances (ODSs) and greenhouse gases (GHGs) is important to verify the success of the Montreal Protocol. So far, nonlinearity in the O3 response to ODS and GHG changes has been mostly neglected. In this study we explicitly account for nonlinear O3 changes and aim to clarify their relevance in the past. We show that both O3 chemistry and transport are significantly affected by nonlinearity.
Atmos. Chem. Phys. Discuss., 15, 9253-9291, doi:10.5194/acpd-15-9253-2015, 2015
Springtime variability of lower tropospheric ozone over Eastern Asia: contributions of cyclonic activity and pollution as observed from space with IASI
Atmos. Chem. Phys. Discuss., 15, 9203-9252, doi:10.5194/acpd-15-9203-2015, 2015
Stratospheric geoengineering impacts on El Niño/Southern Oscillation
Summary: This is a first look at how the El Niño/Southern Oscillation (ENSO) might change under a regime of stratospheric geoengineering (GE). We find neither ENSO event frequency nor ENSO event amplitude will be different under various GE experiments than they would under unabated global warming. We additionally find substantial disagreement between models in depicting ENSO amplitude and frequency. Additionally, output from several GCMs is excluded from comparison due to unrealistic ENSO variability.
Atmos. Chem. Phys. Discuss., 15, 9173-9202, doi:10.5194/acpd-15-9173-2015, 2015
The role of semi-volatile organic compounds in the mesoscale evolution of biomass burning aerosol: a modelling case study of the 2010 mega-fire event in Russia
Summary: (1) The mesoscale evolution of aerosol from open biomass burning (BB) has been successfully simulated using the volatility basis set (VBS) approach to organic aerosol (OA) modeling. (2) The simulations made for the region and period affected by the Russian 2010 wildfires are found to be inconsistent with available measurements, when OA ageing processes are essentially disregarded. (3) Using the VBS approach improves the agreement of "top-down" and "bottom-up" estimates of BB aerosol emissions.
Atmos. Chem. Phys. Discuss., 15, 9107-9172, doi:10.5194/acpd-15-9107-2015, 2015
PLAM – a meteorological pollution index for air quality and its applications in fog-haze forecasts in north China
Summary: On the basis of parameterized meteorological condition principle method, this paper discussed the mutual impact of emission and meteorological condition, and studied the structure and function of meteorological conditions PLAM index in quantitatively identifying, diagnosing and forecasting large scope of fog-haze weather. A new model of PLAM/h – the meteorological pollution Index for air quality has been developed and used in NRT air quality forecasts, by considering both meteorology and polluta
Atmos. Chem. Phys. Discuss., 15, 9077-9106, doi:10.5194/acpd-15-9077-2015, 2015
Contribution from biogenic organic compounds to particle growth during the 2010 BEACHON-ROCS campaign in a Colorado temperate needle leaf forest
Atmos. Chem. Phys. Discuss., 15, 9033-9075, doi:10.5194/acpd-15-9033-2015, 2015
Patterns in atmospheric carbonaceous aerosols in China: emission estimates and observed concentrations
Summary: We present an emission inventory with quantified uncertainties of organic carbon (OC) and elemental carbon (EC) in China. New emission factors from local measurements lead to lower OC emissions than previous studies. We use ground observations to test the levels, trends and spatial pattern of the emissions. The improvement over prior inventories is indicated by inter-annual comparison and correlation analysis between emissions and observations. Sources with high primary OC/EC are underestimated.
Atmos. Chem. Phys. Discuss., 15, 8983-9032, doi:10.5194/acpd-15-8983-2015, 2015
Comparison of OMI UV observations with ground-based measurements at high northern latitudes
Summary: Surface erythemal UV data from the Ozone Monitoring Instrument (OMI) are validated for high northern latitudes (Arctic and Scandinavia) using ground-based measurements. The bias in OMI data caused by incorrect assumptions of the surface albedo are quantified and the mechanism that causes this bias is discussed. Methods to improve the accuracy of OMI data products are presented.
Atmos. Chem. Phys. Discuss., 15, 8933-8981, doi:10.5194/acpd-15-8933-2015, 2015
Comparing the CarbonTracker and TM5-4DVar data assimilation systems for CO2 surface flux inversions
Summary: We compare two different data assimilation systems for estimating sources and sinks of CO_2 from a concentration measurements. The systems are Carbontracker and TM5-4DVar, which have both been used in a number of scientific studies. We analyze the differences between both models as well as the sensitivity of the estimated sources and sinks to the observation coverage. The results provide a lower limit for the uncertainty of surface carbon fluxes with the current measurement network.
Atmos. Chem. Phys. Discuss., 15, 8883-8932, doi:10.5194/acpd-15-8883-2015, 2015
Atmospheric isoprene ozonolysis: impacts of stabilized Criegee intermediate reactions with SO2, H2O and dimethyl sulfide
Summary: Stabilised Criegee intermediates (SCI) are formed through alkene-ozone reactions, which occur throughout the atmospheric boundary layer. Recent direct laboratory studies have shown that SCI react rapidly with SO2, NO2 and other trace gases, affecting air quality and climate. We present experimental data from the EUPHORE atmospheric simulation chamber, in which we determine the effects of the ozonolysis of isoprene, on the oxidation of SO2 as a function of H2O and dimethyl sulfide concentration.
Atmos. Chem. Phys. Discuss., 15, 8839-8881, doi:10.5194/acpd-15-8839-2015, 2015
On the use of satellite derived CH4 / CO2 columns in CH4 flux inversions
Summary: This study attempts to find the feasibility of a new assimilation method of the satellite measurements of CH4 and CO2 for optimization of their surface fluxes in a synthetic environment. Instead of their absolute concentrations, we assimilate the ratios of their concentrations (CH4/CO2) in our inversion. Doing so helps us to reduce the effect of atmospheric scattering on the measurements in our system. However, assimilation of a ratio makes the inversion non-linear.
Atmos. Chem. Phys. Discuss., 15, 8801-8838, doi:10.5194/acpd-15-8801-2015, 2015
Effect of gravity wave temperature fluctuations on homogeneous ice nucleation in the tropical tropopause layer
Atmos. Chem. Phys. Discuss., 15, 8771-8799, doi:10.5194/acpd-15-8771-2015, 2015
A tropospheric chemistry reanalysis for the years 2005–2012 based on an assimilation of OMI, MLS, TES and MOPITT satellite data
Summary: This paper reports on an eight-year reanalysis of tropospheric chemistry based on an assimilation of multiple satellite-derived data sets. The reanalysis performed well on regional and global scales and for seasonal and interannual variations. The simultaneous assimilation of multiple species data, involving the optimisation of both concentration and emission fields, provides unique information on year-to-year variations of the atmospheric environment.
Atmos. Chem. Phys. Discuss., 15, 8687-8770, doi:10.5194/acpd-15-8687-2015, 2015
In-situ, satellite measurement and model evidence for a~dominant regional contribution to fine particulate matter levels in the Paris Megacity
Summary: A detailed characterization of air quality in Paris (France), a megacity of more than 10 million inhabitants, during two one month intensive campaigns and from additional one year observations, revealed that about 70% of the fine particulate matter (PM) at urban background is transported on average into the megacity from upwind regions. A major part of organic PM is of modern origin (woodburning, cooking activities, secondary formation from biogenic VOC).
Atmos. Chem. Phys. Discuss., 15, 8647-8686, doi:10.5194/acpd-15-8647-2015, 2015
The impact of parameterising light penetration into snow on the photochemical production of NOx and OH radicals in snow
Atmos. Chem. Phys. Discuss., 15, 8609-8646, doi:10.5194/acpd-15-8609-2015, 2015
Past changes in the vertical distribution of ozone – Part 3: Analysis and interpretation of trends
Summary: Trends in the vertical distribution of ozone are reported for new and recently revised datasets. The amount of ozone-depleting compounds in the stratosphere peaked in the second half of the 1990s. We examine the trends before and after that peak to see if any change in trend is discernible. The previously reported decreases are confirmed. Further the downward trend in upper stratospheric ozone has not continued. The possible significance of any increase is discussed in detail.
Atmos. Chem. Phys. Discuss., 15, 8565-8608, doi:10.5194/acpd-15-8565-2015, 2015
Deriving polarization properties of desert-reflected solar spectra with PARASOL data
Atmos. Chem. Phys. Discuss., 15, 8525-8564, doi:10.5194/acpd-15-8525-2015, 2015
A numerical study of convection in rainbands of Typhoon Morakot (2009) with extreme rainfall: roles of pressure perturbations with low-level wind maxima
Atmos. Chem. Phys. Discuss., 15, 8479-8523, doi:10.5194/acpd-15-8479-2015, 2015
Potential source regions and processes of the aerosol in the summer Arctic
Summary: Particle size distributions from four summer cruises of the Swedish icebreaker Oden were combined with back trajectories and pack ice information in a cluster algorithm to investigate source areas and aerosol formation in the central Arctic. Five source regions and three aerosol types resulted. Long travel times over ice, combined with more open water conditions shortly before air mass arrival seem to control the formation of ultrafine particles over the central Arctic pack ice.
Atmos. Chem. Phys. Discuss., 15, 8429-8478, doi:10.5194/acpd-15-8429-2015, 2015
Some insights into the condensing vapors driving new particle growth to CCN sizes on the basis of hygroscopicity measurements
Atmos. Chem. Phys. Discuss., 15, 8403-8427, doi:10.5194/acpd-15-8403-2015, 2015
Regional-scale transport of air pollutants: impacts of southern California emissions on Phoenix ground-level ozone concentrations
Summary: Emission sensitivity studies, using WRF-Chem at 1.3km that was validated by observations, indicate the Arizona (AZ) emissions dominate on daily maximum 8-hr average (DMA8) [O3] in Phoenix (PHX). Southern California (SoCal) emission contribute to DMA8 [O3] for the PHX from a few ppb to over 30 ppb. [O3] from SoCal and AZ emissions exhibits diurnal characteristics. Pollutants near the SoCal coasts are transported to PHX by local circulations with different mechanisms.
Atmos. Chem. Phys. Discuss., 15, 8361-8401, doi:10.5194/acpd-15-8361-2015, 2015
The NOx dependence of bromine chemistry in the Arctic atmospheric boundary layer
Atmos. Chem. Phys. Discuss., 15, 8329-8360, doi:10.5194/acpd-15-8329-2015, 2015
Continental pollution in the Western Mediterranean Basin: vertical profiles of aerosol and trace gases measured over the sea during TRAQA 2012 and SAFMED 2013
Summary: Observations from this study indicate that continental pollution largely affects the atmospheric composition and structure of the Western Mediterranean basin. Pollution plumes reach 3000-4000 m in altitude and present a very complex and highly stratified structure characterized by fresh and aged layers both in the boundary layer and in the free troposphere. Also we report the observations of high levels of ultrafine particles over the basin, possibly linked to new particle formation events.
Atmos. Chem. Phys. Discuss., 15, 8283-8328, doi:10.5194/acpd-15-8283-2015, 2015
MACC regional multi-model ensemble simulations of birch pollen dispersion in Europe
Summary: The paper presents the first ensemble modelling experiment for forecasting the atmospheric dispersion of birch pollen in Europe. The study included 7 models of MACC-ENS tested over the season of 2010 and applied for 2013 in forecasting and re-analysis modes. The results were compared with observations in 11 countries, members of European Aeroallergen Network. The models successfully reproduced the timing of the unusually late season of 2013 but had more difficulties with absolute concentrations.
Atmos. Chem. Phys. Discuss., 15, 8243-8281, doi:10.5194/acpd-15-8243-2015, 2015
Source contributions to 2012 summertime aerosols in the Euro-Mediterranean region
Atmos. Chem. Phys. Discuss., 15, 8191-8242, doi:10.5194/acpd-15-8191-2015, 2015
Airborne measurements of new particle formation in the free troposphere above the Mediterranean Sea during the HYMEX campaign
Summary: In the present paper, we report airborne measurements of new particle formation (NPF) above the Mediterranean sea (HYMEX campaign). We show that NPF is occurring over large areas above the sea but the process is clearly promoted at high altitude, above 1000 m, i.e. frequently in the free troposphere. Also, NPF seems to be mainly influenced by local processes occurring above the sea. After they formed, particles slowly grow at high altitude while being poorly depleted by coagulation processes.
Atmos. Chem. Phys. Discuss., 15, 8151-8189, doi:10.5194/acpd-15-8151-2015, 2015
Organic photolysis reactions in tropospheric aerosols: effect on secondary organic aerosol formation and lifetime
Summary: Our study combines process and global chemistry modeling to investigate the potential effect of gas- and particle-phase organic photolysis reactions on the formation and lifetime of Secondary Organic Aerosols (SOA). Photolysis of the oxidation intermediates that partition between gas and particle phases to form SOA are not included in 3D models. Our results suggest that exposure to UV light can suppress the formation of SOA or even lead to its substantial loss (comparable to wet deposition).
Atmos. Chem. Phys. Discuss., 15, 8113-8149, doi:10.5194/acpd-15-8113-2015, 2015
Formation of secondary organic aerosol in the Paris pollution plume and its impact on surrounding regions
Summary: Secondary organic aerosol (SOA) is an important pollutant formed from megacity emissions at a regional scale. An original method based on ratios of different pollutants is used to specifically validate the aerosol scheme (the volatility basis set approach) within a CTM. The method is applied to airborne measurements performed within the Paris plume during the MEGAPOLI summer campaign. Simulations indicate that SOA of anthropogenic origin has a significant impact on regional air quality.
Atmos. Chem. Phys. Discuss., 15, 8073-8111, doi:10.5194/acpd-15-8073-2015, 2015
OMI tropospheric NO2 profiles from cloud slicing: constraints on surface emissions, convective transport and lightning NOx
Atmos. Chem. Phys. Discuss., 15, 8017-8072, doi:10.5194/acpd-15-8017-2015, 2015
VOC species and emission inventory from vehicles and their SOA formation potentials estimation in Shanghai, China
Summary: SOA formations from vehicle exhausts contribute 15% and 22% of total organic aerosols observed in the summer and winter in urban Shanghai. VOC emissions from gasoline and diesel vehicles contribute 38% and 62% of vehicular SOA formation after 24 hours of photochemical aging. SOA formation contributions from other sources (e.g. coal burning, biomass burning, cooking, dust, etc.) as well as IVOCs and SVOCs from the combustion sources are also important in urban Shanghai.
Atmos. Chem. Phys. Discuss., 15, 7977-8015, doi:10.5194/acpd-15-7977-2015, 2015
Utilization of O4 slant column density to derive aerosol layer height from a spaceborne UV-visible hyperspectral sensor: sensitivity and case study
Summary: The sensitivities of oxygen-dimer (O4) slant column densities (SCDs) to changes in aerosol layer height are investigated using simulated radiances by a radiative transfer model, Linearized Discrete Ordinate Radiative Transfer (LIDORT), and Differential Optical Absorption Spectroscopy (DOAS) technique. A new algorithm is developed and tested to derive the aerosol effective height for cases over East Asia using radiance data from the Ozone Monitoring Instrument (OMI).
Atmos. Chem. Phys. Discuss., 15, 7933-7975, doi:10.5194/acpd-15-7933-2015, 2015
Transport of Antarctic stratospheric strongly dehydrated air into the troposphere observed during the HALO-ESMVal campaign 2012
Atmos. Chem. Phys. Discuss., 15, 7895-7932, doi:10.5194/acpd-15-7895-2015, 2015
Chemical composition, microstructure, and hygroscopic properties of aerosol particles at the Zotino Tall Tower Observatory (ZOTTO), Siberia, during a summer campaign
Summary: Our manuscript describes the hygroscopic properties of accumulation- and coarse-mode aerosol particles sampled at the ZOTTO in Central Siberia (61º N; 89º E). The hygroscopic growth measurements were supplemented with chemical analyses of the samples. In addition, the microstructure and chemical composition of aerosol particles were analyzed by X-ray micro-spectroscopy (STXM-NEXAFS) and transmission electron microscopy (TEM).
Atmos. Chem. Phys. Discuss., 15, 7837-7893, doi:10.5194/acpd-15-7837-2015, 2015
Prognostic precipitation with three liquid water classes in the ECHAM5-HAM GCM
Summary: We have introduced prognostic precipitation for both liquid (drizzle and rain) and solid (snow) phase precipitation into the global circulation model ECHAM5-HAM. This has a significant effect on the clouds and the parameterized collection rates, also reducing the sensitivityof the liquid water path to the anthropogenic aerosol forcing. Altogether the results suggest that the treatment of precipitation in global circulation models has a significant influence on the phase and lifetime of clouds.
Atmos. Chem. Phys. Discuss., 15, 7783-7836, doi:10.5194/acpd-15-7783-2015, 2015
Two decades of water vapor measurements with the FISH fluorescence hygrometer: a review
Atmos. Chem. Phys. Discuss., 15, 7735-7782, doi:10.5194/acpd-15-7735-2015, 2015
Improvement of climate predictions and reduction of their uncertainties using learning algorithms
Atmos. Chem. Phys. Discuss., 15, 7707-7734, doi:10.5194/acpd-15-7707-2015, 2015
Sources, transport and deposition of iron in the global atmosphere
Atmos. Chem. Phys. Discuss., 15, 7645-7705, doi:10.5194/acpd-15-7645-2015, 2015
On the radiative impact of aerosols on photolysis rates: comparison of simulations and observations in the Lampedusa island during the ChArMEx/ADRIMED campaign
Summary: We studied the impact of aerosols on tropospheric photolysis rates at Lampedusa during the CharMEx/ADRIMED campaign, in june 2013. It is shown by using the CHIMERE chemistry-transport model (CTM) as well as in-situ and remote-sensing measurements that taking into account the radiative effect of the tropospheric aerosols improves the ability of the model to reproduce the observed photolysis rates. It is hence important for CTMs to include the radiative effect of aerosols on photochemistry.
Atmos. Chem. Phys. Discuss., 15, 7585-7643, doi:10.5194/acpd-15-7585-2015, 2015
Sensitivities of Lagrangian modeling of mid-latitude cirrus clouds to trajectory data quality
Summary: We have examined the sensitivities of Lagrangian cirrus modeling on input data uncertainties. We found a strong dependence on the temporal resolution of the trajectories and underlying NWP data. With increasing temporal resolution, the simulated profiles approach the measured profile. Further we found a large variability in the vertical wind spectrum from day to day, demonstrating the necessity to apply NWP models with high spatial and temporal resolution for Lagrangian cirrus modeling.
Atmos. Chem. Phys. Discuss., 15, 7535-7584, doi:10.5194/acpd-15-7535-2015, 2015
Dust–air pollution dynamics over the Eastern Mediterranean
Atmos. Chem. Phys. Discuss., 15, 7493-7534, doi:10.5194/acpd-15-7493-2015, 2015
A comprehensive inventory of ship traffic exhaust emissions in the European sea areas in 2011
Summary: This manuscript describes the emissions from shipping in European sea areas. The work is based on automatic position reports (AIS) sent by ships and reflects realistic activity patterns of ships. The work demonstrates that it is feasible to construct a full bottom-up emission inventories based on large-volume activity data sets.
Atmos. Chem. Phys. Discuss., 15, 7459-7491, doi:10.5194/acpd-15-7459-2015, 2015
A 12 year observation of water-soluble inorganic ions in TSP aerosols collected at a remote marine location in the western North Pacific: an outflow region of Asian dust
Atmos. Chem. Phys. Discuss., 15, 7419-7458, doi:10.5194/acpd-15-7419-2015, 2015
Examining the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol formation during the 2013 Southern Oxidant and Aerosol Study (SOAS) at the Look Rock, Tennessee, ground site
Summary: Isoprene epoxydiols (IEPOX) are major gas-phase products from the atmospheric oxidation of isoprene that yield secondary organic aerosol (SOA) by reactive uptake onto acidic sulfate aerosol. We report a substantial contribution of IEPOX-derived SOA to the total fine aerosol collected during summer. IEPOX-derived SOA measured by online and offline mass spectrometry techniques is correlated with acidic sulfate aerosol, demonstrating the critical role of anthropogenic emissions in its formation.
Atmos. Chem. Phys. Discuss., 15, 7365-7417, doi:10.5194/acpd-15-7365-2015, 2015
The anthropogenic contribution to atmospheric black carbon concentrations in southern Africa: a WRF-Chem modeling study
Summary: The numerical model WRF-Chem is used to estimate the contribution of anthropogenic emissions to BC, aerosol optical depth and atmospheric heating rates over southern Africa. An evaluation of the model with observational data including long-term BC measurements shows that the basic meteorology is reproduced reasonably well but simulated near-surface BC concentrations are underestimated by up to 50%. It is found that up to 100% of the BC in highly industrialized regions is of anthropogenic origin.
Atmos. Chem. Phys. Discuss., 15, 7309-7363, doi:10.5194/acpd-15-7309-2015, 2015
The impact of speciated VOCs on regional ozone increment derived from measurements at the UK EMEP supersites between 1999 and 2012
Summary: In this study the regional component of ground level ozone is linked to the chemical loss of 27 measured VOCs at two UK monitoring sites, and integrated with gridded European VOC emissions. The relative VOC chemical loss indicates that emission controls of a large number of VOCs, and targeting VOCs with highest chemical loss, are both required to reduce regional ozone. The benefit resulting from the disaggregation of VOC source sectors to the identification of high VOC emitting sources is shown.
Atmos. Chem. Phys. Discuss., 15, 7267-7308, doi:10.5194/acpd-15-7267-2015, 2015
A simple formulation of the CH2O photolysis quantum yields
Atmos. Chem. Phys. Discuss., 15, 7239-7266, doi:10.5194/acpd-15-7239-2015, 2015
Five-year flask measurements of long-lived trace gases in India
Summary: We present 5-year flask measurements (2007–2011) of greenhouse gases (GHGs) at three atmospheric stations in India. The results suggest significant sources of CO2, CH4, N2O, CO, and H2 over South and NE India, while SF6 sources are weak. The seasonal cycles for each species reflect the seasonality of sources/sinks and influences of the Indian monsoon circulations. The data show potential to infer regional patterns of GHG fluxes and atmospheric transport over this under-documented region.
Atmos. Chem. Phys. Discuss., 15, 7171-7238, doi:10.5194/acpd-15-7171-2015, 2015
Seasonal variation of secondary organic aerosol in Nam Co, Central Tibetan Plateau
Summary: 1) Seasonal trends of SOA tracers and its origins were studied in the remote TP for the first time. 2) Seasonal variation of isoprene SOA tracers was mainly influenced by emission. 3) Due to the transport from the Indian subcontinent, aromatics SOA tracer presented relatively higher levels in the summer and elevated mass fractions in the winter. 4) Biogenic SOC dominated over anthropogenic SOC in the remote TP.
Atmos. Chem. Phys. Discuss., 15, 7141-7169, doi:10.5194/acpd-15-7141-2015, 2015
Analysis of CO2 mole fraction data: first evidence of large-scale changes in CO2 uptake at high northern latitudes
Summary: The two new results from our analysis are: 1) a significant revision to phase changes in atmospheric CO2 and 2) an indirect observation that is consistent with high northern latitude ecosystems actively taking up more CO2.
Atmos. Chem. Phys. Discuss., 15, 7089-7139, doi:10.5194/acpd-15-7089-2015, 2015
Influence of the aerosol solar extinction on photochemistry during the 2010 Russian wildfires episode
Atmos. Chem. Phys. Discuss., 15, 7057-7087, doi:10.5194/acpd-15-7057-2015, 2015
Contrail life cycle and properties from one year of MSG/SEVIRI rapid-scan images
Atmos. Chem. Phys. Discuss., 15, 7019-7055, doi:10.5194/acpd-15-7019-2015, 2015
Trapping, chemistry and export of trace gases in the South Asian summer monsoon observed during CARIBIC flights in 2008
Atmos. Chem. Phys. Discuss., 15, 6967-7018, doi:10.5194/acpd-15-6967-2015, 2015
Air–snow transfer of nitrate on the East Antarctic plateau – Part 2: An isotopic model for the interpretation of deep ice-core records
Summary: In this paper, we describe the development of a numerical model which aims at representing nitrate recycling at the air-snow interface on the East Antarctic plateau. Stable isotopes are used as diagnostic and evaluation tools by comparing the model's results to recent field measurements of nitrate and key atmospheric species at Dome C, Antarctica. From sensitivity tests conducted with the model, we propose a framework for the interpretation of the nitrate isotope record in deep ice cores.
Atmos. Chem. Phys. Discuss., 15, 6887-6966, doi:10.5194/acpd-15-6887-2015, 2015
Wet scavenging limits the detection of aerosol–cloud–precipitation interactions
Summary: Wet scavenging generates differences between the aerosol properties in clear-sky scenes (observed by satellites) and cloudy scenes, leading to different aerosol-precipitation relationships in satellite data and global models. Convective systems usually draw in air from clear-sky regions, but global models have difficulty separating this aerosol from the aerosol in cloudy scenes within a model gridbox. This may prevent models from reproducing the observed aerosol-precipitation relationships.
Atmos. Chem. Phys. Discuss., 15, 6851-6886, doi:10.5194/acpd-15-6851-2015, 2015
Changing shapes and implied viscosities of suspended submicron particles
Summary: The present work estimates the viscosity of submicron organic particles while they are still suspended as an aerosol without further post-processing techniques that can possibly alter the properties of semivolatile materials. The results imply that atmospheric particles, at least those similar to the ones of this study and for low to middle RH regimes, can reach equilibrium or react rather slowly with the surrounding gas phase, on timescales even longer than the residence time in the atmosphere.
Atmos. Chem. Phys. Discuss., 15, 6821-6850, doi:10.5194/acpd-15-6821-2015, 2015
Chemical aging of single and multicomponent biomass burning aerosol surrogate-particles by OH: implications for cloud condensation nucleus activity
Summary: Aerosol particles undergo chemical modification during atmospheric transport due to reactions with trace gas species such as OH radicals affecting cloud formation and, thus, prediction of climate. Here, the cloud formation potential of surrogate biomass burning aerosol (BBA) is studied as a function of particle composition and OH exposure. We find that OH oxidation can alter the cloud formation potential of BBA but its significance depends on the available water-soluble particulate material.
Atmos. Chem. Phys. Discuss., 15, 6771-6819, doi:10.5194/acpd-15-6771-2015, 2015
Simulating CO2 profiles using NIES TM and comparison with HIAPER Pole-to-Pole Observations
Atmos. Chem. Phys. Discuss., 15, 6745-6770, doi:10.5194/acpd-15-6745-2015, 2015
Fire emission heights in the climate system – Part 2: Impact on transport, Black Carbon concentrations and radiation
Summary: Global aerosol-climate models usually prescribe wildfire emission injections at fixed atmospheric levels. Here, we quantify the impact of prescribed and parameterized emission heights on aerosol long-range transport and radiation. For global emission height changes of 1.5-3.5 km, we find a top of atmosphere radiative forcing of 0.05-0.1 Wm-2. Replacing prescribed emission heights by a simple plume height parametrization only marginally improves the model performance in aerosol optical thickness.
Atmos. Chem. Phys. Discuss., 15, 6695-6744, doi:10.5194/acpd-15-6695-2015, 2015
Fire emission heights in the climate system – Part 1: Global plume height patterns simulated by ECHAM6-HAM2
Summary: In this paper we discuss the representation of wildfire emission heights in global climate models. Our implementation of a simple, semi-empirical plume height parametrization shows reasonable agreement with observations and also with a complex analytical plume rise model. Realistic simulations of global plume height patterns require plume height parametrizations which consider fire intensity as well as meteorological conditions. In contrast, diurnal and seasonal cycles are of minor importance.
Atmos. Chem. Phys. Discuss., 15, 6645-6693, doi:10.5194/acpd-15-6645-2015, 2015
Seasonal trends in concentrations and fluxes of volatile organic compounds above central London
Summary: Concentrations and fluxes of selected volatile organic compounds were measured over a five month period in central London as part of the ClearfLo project using a proton transfer reaction-mass spectrometer. Emission sources within the city were inferred from spatio-temporal patterns and showed a non-negligible biogenic source during warmer months, which was modelled using the Guenther 95 algorithm. Comparisons were made with the local emissions inventories showing mostly underestimated emissions.
Atmos. Chem. Phys. Discuss., 15, 6601-6644, doi:10.5194/acpd-15-6601-2015, 2015
Water vapour profiles from Raman lidar automatically calibrated by microwave radiometer data during HOPE
Summary: We present a method to derive water vapour profiles from Raman lidar measurements calibrated by the integrated water vapour from a collocated microwave radiometer. These simultaneous observations provide an operational and continuous measurement of water vapour profiles. The stability of the calibration factor allows to calibrate the lidar even in the presence of clouds. Based on this approach water vapour profiles can be retrieved during all non-precipitating conditions.
Atmos. Chem. Phys. Discuss., 15, 6567-6599, doi:10.5194/acpd-15-6567-2015, 2015
Hygroscopic and phase separation properties of ammonium sulfate/organic/water ternary solutions
Summary: This work investigates hygroscopic properties of internally mixed organic/inorganic aerosol particles. Aerosol particles containing organic and inorganic components can phase separate under certain relative humidity conditions, creating particles with inorganic core and an organic shell. This paper explores whether water uptake from gaseous phase still occurs in such phase separated systems. It finds that phase separation does not inhibit water uptake for the five systems that were studied.
Atmos. Chem. Phys. Discuss., 15, 6537-6566, doi:10.5194/acpd-15-6537-2015, 2015
Modelling impact of climate change on atmospheric transport and fate of persistent organic pollutants in the Arctic
Atmos. Chem. Phys. Discuss., 15, 6509-6535, doi:10.5194/acpd-15-6509-2015, 2015
Effect of atmospheric ageing on volatility and ROS of biodiesel exhaust nano-particles
Summary: The study concludes that more saturated and more oxygenated diesel fuels caused more volatile particles carrying more reactive oxygenated species whether before or after ageing. Flow-throw reactors are reliable tools for carrying out experiments on diesel exhaust ageing and finding out the potential of diesel fuels in generation of secondary organic aerosols.
Atmos. Chem. Phys. Discuss., 15, 6481-6508, doi:10.5194/acpd-15-6481-2015, 2015
Smoke aerosol properties and ageing effects for Northern temperate and boreal regions derived from AERONET source and age attribution
Summary: The study found significant differences in smoke plumes attributed to different vegetation type fires in northern temperate and boreal regions. Plume particle sizes and optical properties varied not only when comparing grass and forest emissions, but also plumes from different forest types. Particles were found to increase in size in ageing plumes. Determined growth rates were significant and consistent between the emissions of different origin.
Atmos. Chem. Phys. Discuss., 15, 6445-6479, doi:10.5194/acpd-15-6445-2015, 2015
Photochemical aging of volatile organic compounds associated with oil and natural gas extraction in the Uintah Basin, UT, during a wintertime ozone formation event
Summary: Extraction of natural gas and oil is associated with a range of possible atmospheric environmental issues. Here we present an analysis of gas-phase hydrocarbon measurements taken in an oil and natural gas extraction area in Utah during a period of high wintertime ozone. We are able to constrain important chemical parameters related to emission sources and rates, hydrocarbon photochemistry, and VOC composition.
Atmos. Chem. Phys. Discuss., 15, 6403-6444, doi:10.5194/acpd-15-6403-2015, 2015
Tropospheric ozone variability in the tropics from ENSO to MJO and shorter timescales
Summary: Aura OMI and MLS measurements are combined to produce daily maps of tropospheric ozone beginning October 2004. We show that El Niño Southern Oscillation (ENSO) related inter-annual change in tropospheric ozone in the tropics is small compared to combined intra-seasonal/Madden-Julian Oscillation (MJO) and shorter timescale variability. Outgoing Longwave Radiation indicates that deep convection is the primary driver of the observed ozone variability on all timescales.
Atmos. Chem. Phys. Discuss., 15, 6373-6401, doi:10.5194/acpd-15-6373-2015, 2015
NOx emission estimates during the 2014 Youth Olympic Games in Nanjing
Atmos. Chem. Phys. Discuss., 15, 6337-6372, doi:10.5194/acpd-15-6337-2015, 2015
Evaluation of the MACC operational forecast system – potential and challenges of global near-real-time modelling with respect to reactive gases in the troposphere
Atmos. Chem. Phys. Discuss., 15, 6277-6335, doi:10.5194/acpd-15-6277-2015, 2015
Reassessing the ratio of glyoxal to formaldehyde as an indicator of hydrocarbon precursor speciation
Atmos. Chem. Phys. Discuss., 15, 6237-6275, doi:10.5194/acpd-15-6237-2015, 2015
Laboratory studies of collection efficiency of sub-micrometer aerosol particles by cloud droplets on a single droplet basis
Atmos. Chem. Phys. Discuss., 15, 6207-6236, doi:10.5194/acpd-15-6207-2015, 2015
An investigation of how radiation may cause accelerated rates of tropical cyclogenesis and diurnal cycles of convective activity
Atmos. Chem. Phys. Discuss., 15, 6125-6205, doi:10.5194/acpd-15-6125-2015, 2015
Source apportionment of methane and nitrous oxide in California's San Joaquin Valley at CalNex 2010 via positive matrix factorization
Summary: We perform a positive matrix factorization (PMF) based source apportionment by combining GHG measurements with coincident VOC measurements in the San Joaquin valley of California. Using VOCs as source tracers, we identify dairies and livestock as major sources of CH4 and N2O in the region. Agriculture is a significant source of N2O enhancements too, while vehicle emissions are found to be a negligible source of N2O. The findings are relevant to the state’s GHG inventory verification process.
Atmos. Chem. Phys. Discuss., 15, 6077-6124, doi:10.5194/acpd-15-6077-2015, 2015
CALIOP near-real-time backscatter products compared to EARLINET data
Summary: The expedited near-real-time Level 1.5 Cloud-Aerosol Lidar with Orthogonal Polarization products were evaluated against data from the ground-based European Aerosol Research Lidar Network. Over a period of three years, lidar data from 48 CALIOP overpasses with ground tracks within a 100 km distance from an operating EARLINET station were analysed. The influence of PBL, FT and the presence of FT layers with high attenuated backscatter on the agreement was assessed.
Atmos. Chem. Phys. Discuss., 15, 6041-6075, doi:10.5194/acpd-15-6041-2015, 2015
Production of peroxy nitrates in boreal biomass burning plumes over Canada during the BORTAS campaign
Atmos. Chem. Phys. Discuss., 15, 6009-6040, doi:10.5194/acpd-15-6009-2015, 2015
Brown carbon aerosol in the North American continental troposphere: sources, abundance, and radiative forcing
Atmos. Chem. Phys. Discuss., 15, 5959-6007, doi:10.5194/acpd-15-5959-2015, 2015
Global OZone Chemistry And Related Datasets for the Stratosphere (GOZCARDS): methodology and sample results with a focus on HCl, H2O, and O3
Atmos. Chem. Phys. Discuss., 15, 5849-5957, doi:10.5194/acpd-15-5849-2015, 2015
Sulfur dioxide (SO2) from MIPAS in the upper troposphere and lower stratosphere 2002–2012
Atmos. Chem. Phys. Discuss., 15, 5801-5847, doi:10.5194/acpd-15-5801-2015, 2015
Dust aerosol and optical properties over North Africa simulated with the ALADIN numerical prediction model from 2006 to 2010
Summary: This manuscript focuses on the elaboration and interpretation of a dust aerosol climatology for North Africa using an operational numerical weather prediction model. The use of an NWP model for this type of study is new and allows to better represent the coupled processes between the surface and the atmosphere and mesoscales process. The aim of these simulations is to quantify the dust emission and deposition, locate the major areas of dust emission and establish a climatology of aerosol optical
Atmos. Chem. Phys. Discuss., 15, 5751-5799, doi:10.5194/acpd-15-5751-2015, 2015
Heterogeneous reaction of peroxyacetic acid and hydrogen peroxide on ambient aerosol particles under dry and humid conditions: kinetics, mechanism and implications
Summary: The present study provides the first measurement for the uptake coefficient of gaseous peroxide compounds including peroxyacetic acid and hydrogen peroxide on the ambient particles (PM2.5 and Asian Storm Dust) over a wide range of relative humidity. The measured uptake coefficient values suggest that the heterogeneous reaction on the ambient particles plays an important role in the atmospheric budgets of peroxide compounds and potentially affects the components of aerosols in the atmosphere.
Atmos. Chem. Phys. Discuss., 15, 5713-5750, doi:10.5194/acpd-15-5713-2015, 2015
Ultrafine particle sources and in-situ formation in a European megacity
Atmos. Chem. Phys. Discuss., 15, 5663-5712, doi:10.5194/acpd-15-5663-2015, 2015
What's the real role of iron-oxides in the optical properties of dust aerosols?
Summary: Three different continuous datasets for complex refractive indices of hematite are employed in climate models, the real role of iron-oxides in the optical properties of dust aerosols becomes a key scientific question, and we address this problem by considering different refractive indices, size distributions, and more logical weight fractions and mixing states of hematite.More laboratory measurements should be taken into account when assessing the effect of mineral dust on climate forcing.
Atmos. Chem. Phys. Discuss., 15, 5619-5662, doi:10.5194/acpd-15-5619-2015, 2015
The importance of interstitial particle scavenging by cloud droplets in shaping the remote aerosol size distribution and global aerosol-climate effects
Summary: In this paper we show that coagulation of cloud droplets with interstitial aerosol particles, a process often neglecting in atmospheric aerosol models, has a significant impact on aerosol size distributions and radiative forcings.
Atmos. Chem. Phys. Discuss., 15, 5589-5618, doi:10.5194/acpd-15-5589-2015, 2015
On the reversibility of transitions between closed and open cellular convection
Summary: Most research on the relationship between aerosol and closed/open cell transitions tends to focus on the closed to open transition. Here we address the two-way transition between closed and open cellular states using a cloud resolving model. We find inherent asymmetry in the transitions and explain the source of the asymmetry. Results are supported by a dynamical system analogue to the full system.
Atmos. Chem. Phys. Discuss., 15, 5553-5588, doi:10.5194/acpd-15-5553-2015, 2015
Ocean mediation of tropospheric response to reflecting and absorbing aerosols
Summary: Strong solar heating by absorbing aerosols (black carbon) is considered more effective in inducing atmospheric circulation change than reflecting aerosols (sulfate), which do not have direct atmospheric heating effect. Surprisingly, we show that reflecting aerosols induce tropospheric temperature and circulation response similar to that induced by absorbing aerosols. The common response is mediated by the ocean through SST gradient, a process overlooked so far in aerosol-climate connection.
Atmos. Chem. Phys. Discuss., 15, 5537-5552, doi:10.5194/acpd-15-5537-2015, 2015
Overview of receptor-based source apportionment studies for speciated atmospheric mercury
Summary: Current knowledge of receptor-based studies using speciated atmospheric mercury is reviewed and recommendations for future research needs are provided.
Atmos. Chem. Phys. Discuss., 15, 5493-5536, doi:10.5194/acpd-15-5493-2015, 2015
Compilation and evaluation of gas-phase diffusion coefficients of reactive trace gases in the atmosphere: volume 2. Organic compounds and Knudsen numbers for gas uptake calculations
Atmos. Chem. Phys. Discuss., 15, 5461-5492, doi:10.5194/acpd-15-5461-2015, 2015
The vertical structure of cloud radiative heating over the Indian subcontinent during summer monsoon
Atmos. Chem. Phys. Discuss., 15, 5423-5459, doi:10.5194/acpd-15-5423-2015, 2015
Partitioning and budget of inorganic and organic chlorine species observed by MIPAS-B and TELIS in the Arctic in March 2011
Atmos. Chem. Phys. Discuss., 15, 5391-5422, doi:10.5194/acpd-15-5391-2015, 2015
Molecular composition of aged secondary organic aerosol generated from a mixture of biogenic volatile compounds using ultrahigh resolution mass spectrometry
Atmos. Chem. Phys. Discuss., 15, 5359-5389, doi:10.5194/acpd-15-5359-2015, 2015
Regional data assimilation of multi-spectral MOPITT observations of CO over North America
Summary: We present a high-resolution (0.5x0.667) regional CO inversion over North America in the period of June 2004 – May 2005, using adjoint of GEOS-Chem model and MOPITT CO observations. With optimized lateral boundary conditions, we show that regional inversion analyses can reduce the sensitivity of the CO source estimates to errors in long-range transport and in the distributions of the hydroxyl radical (OH), and consequently, provide better quantification on regional CO source estimates.
Atmos. Chem. Phys. Discuss., 15, 5327-5358, doi:10.5194/acpd-15-5327-2015, 2015
Top-down constraints on atmospheric mercury emissions and implications for global biogeochemical cycling
Summary: A better knowledge of mercury (Hg) emission fluxes into the global atmosphere is important for assessing its human health impacts and evaluating effectiveness of corresponding policy actions. We for the first time apply a top-down approach at global scale to quantitatively estimate present-day mercury emission sources as well as key parameters in a chemical transport model, in order to better constrain the global biogeochemical cycle of mercury.
Atmos. Chem. Phys. Discuss., 15, 5269-5325, doi:10.5194/acpd-15-5269-2015, 2015
Unusual stratospheric ozone anomalies observed in 22 years of measurements from Lauder, New Zealand
Summary: This paper highlights 2 unusual mid-stratospheric ozone anomalies in our 22 year ground-based dataset. One of these is a very large month long increase in June 2001 which we are able to associate with very unusually low equatorial air which persists over Lauder for much of June. The other ozone anomaly persists over about 4 years, and, using MLS data, we show that this is associated with unusually high N2O during this period. We show that this positive ozone and N2O anomaly over Lauder is tempor
Atmos. Chem. Phys. Discuss., 15, 5241-5267, doi:10.5194/acpd-15-5241-2015, 2015
Middle East versus Saharan dust extinction-to-backscatter ratios
Atmos. Chem. Phys. Discuss., 15, 5203-5240, doi:10.5194/acpd-15-5203-2015, 2015
Momentum forcing of the QBO by equatorial waves in recent reanalyses
Atmos. Chem. Phys. Discuss., 15, 5175-5202, doi:10.5194/acpd-15-5175-2015, 2015
Investigation of the adiabatic assumption for estimating cloud micro- and macrophysical properties from satellite and ground
Summary: We investigated the accuracy of quantities relevant for the first indirect aerosol effect, with focus on the cloud droplet number concentration (CDNC) and cloud geometrical depth (H). Therefore we compared differences from satellite and ground-based retrievals for 4 different cases and found the best match for a homogeneous case with relative mean difference of 15% in H and 27% in CDNC. We further evaluated cloud adiabacity and found subadiabatic behaviour consistent with previous studies.
Atmos. Chem. Phys. Discuss., 15, 5129-5173, doi:10.5194/acpd-15-5129-2015, 2015
Size-resolved cloud condensation nuclei concentration measurements in the Arctic: two case studies from the summer of 2008
Atmos. Chem. Phys. Discuss., 15, 5079-5128, doi:10.5194/acpd-15-5079-2015, 2015
Temporal variations of flux and altitude of sulfur dioxide emissions during volcanic eruptions: implications for long-range dispersal of volcanic clouds
Summary: 1-IASI spaceborne imagery is used to reconstruct temporal variations of flux and altitude of volcanic emissions via an inversion procedure.2-Ground-based UV measurements underestimate the SO2 flux by one order of magnitude, due to ash-induced plume opacity.3-Assimilation of SO2 altitude, retrieved directly from IASI, should render the inversion scheme independent of the wind shear prerequisite.4-CALIOP LiDAR observations support the coexistence of SO2 and sulfate aerosols in the volcanic cloud
Atmos. Chem. Phys. Discuss., 15, 5031-5077, doi:10.5194/acpd-15-5031-2015, 2015
Polar processing in a split vortex: early winter Arctic ozone loss in 2012/13
Summary: Sudden Stratospheric warmings (SSWs) cause a rapid rise in lower stratospheric temperatures, terminating conditions favorable to chemical ozone loss. We show that although temperatures rose precipitously during the vortex split SSW in early Jan 2013, because the offspring vortices each remained isolated and in regions that received sunlight, chemical ozone loss continued for over a month after the SSW. Dec/Jan Arctic ozone loss was larger than any previously observed during that period.
Atmos. Chem. Phys. Discuss., 15, 4973-5029, doi:10.5194/acpd-15-4973-2015, 2015
The impact of observing characteristics on the ability to predict ozone under varying polluted photochemical regimes
Summary: Using a simplified air quality forecasting model we explore how characteristicis of air quality observations affect our ability to understand and predict ozone air pollution. We show that the photochemical conditions can strongly influence the observing priorities for ozone prediction. Such as, which species are observed, how well, when, and how frequently. High freqency observations of ozone, NOx and HCHO in combination during the morning and afternoon are particularly advantageous.
Atmos. Chem. Phys. Discuss., 15, 4909-4971, doi:10.5194/acpd-15-4909-2015, 2015
Increasing Arabian dust activity and the Indian Summer Monsoon
Atmos. Chem. Phys. Discuss., 15, 4879-4907, doi:10.5194/acpd-15-4879-2015, 2015
Global evaluation of ammonia bi-directional exchange
Atmos. Chem. Phys. Discuss., 15, 4823-4877, doi:10.5194/acpd-15-4823-2015, 2015
Climate forced air-quality modeling at urban scale: sensitivity to model resolution, emissions and meteorology
Summary: The efficacy of emission policies is explored by coarse resolution modeling applications. These were shown to be biased, overestimating that efficacy indicated in simulations with refined resolution. In order to improve our assessments we need to quantify those biases. In this study we show that the ozone bias of the coarse run is reduced by 40% by adopting higher resolution emissions. For PM2.5 the coarse run cannot selectively incorporate local scale features in order to reduce model error.
Atmos. Chem. Phys. Discuss., 15, 4767-4821, doi:10.5194/acpd-15-4767-2015, 2015
Aircraft measurements of gravity waves in the upper troposphere and lower stratosphere during the START08 Field Experiment
Summary: Based on spectral and wavelet analyses, along with a diagnosis of the polarization relations, this study analyzes in-situ airborne measurements from the 2008 Stratosphere-Troposphere Analyses of Regional Transport (START08) experiment to characterize gravity waves in the extratropical upper troposphere and lower stratosphere (ExUTLS) region. The focus is on the second research flight (RF02), which was dedicated to probing gravity waves associated with strong upper-tropospheric jet-front systems.
Atmos. Chem. Phys. Discuss., 15, 4725-4766, doi:10.5194/acpd-15-4725-2015, 2015
In-situ single submicron particle composition analysis of ice residuals from mountain-top mixed-phase clouds in Central Europe
Atmos. Chem. Phys. Discuss., 15, 4677-4724, doi:10.5194/acpd-15-4677-2015, 2015
Mercury vapor air–surface exchange measured by collocated micrometeorological and enclosure methods – Part II: Bias and uncertainty analysis
Atmos. Chem. Phys. Discuss., 15, 4627-4676, doi:10.5194/acpd-15-4627-2015, 2015
A perturbed parameter model ensemble to investigate 1991 Mt Pinatubo's initial sulfur mass emission
Summary: Model results suggest that the initial mass loading of the 1991 Pinatubo eruption is approximately 14 Mt of SO2. The sulfur injection vertical distribution is strongly skewed towards the lower stratosphere, leading to a peak mass sulfur injection at 19-22 km.
Atmos. Chem. Phys. Discuss., 15, 4601-4625, doi:10.5194/acpd-15-4601-2015, 2015
A large and ubiquitous source of atmospheric formic acid
Summary: Formic acid (HCOOH) is an abundant atmospheric acid that affects precipitation chemistry and acidity. HCOOH measurements over the US are 2-3× larger than can be explained by known sources and sinks, revealing a key gap in current understanding. Observations indicate a large biogenic source plus chemical production across a range of precursors. Model simulations cannot capture the HCOOH diurnal amplitude or nocturnal profile, implying a deposition bias and possibly even larger missing source.
Atmos. Chem. Phys. Discuss., 15, 4537-4599, doi:10.5194/acpd-15-4537-2015, 2015
Estimating global and North American methane emissions with high spatial resolution using GOSAT satellite data
Atmos. Chem. Phys. Discuss., 15, 4495-4536, doi:10.5194/acpd-15-4495-2015, 2015
Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds
Summary: We measured a large suite organic compounds using a recently developed Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a (HR-ToF-CIMS). The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We find that approximately 50% of the detected particle phase mass is associated with compounds having effective vapor pressures 4, or more, orders of magnitude lower than commonly measured products.
Atmos. Chem. Phys. Discuss., 15, 4463-4494, doi:10.5194/acpd-15-4463-2015, 2015
Ozone and NOx chemistry in the eastern US: evaluation of CMAQ/CB05 with satellite (OMI) data
Atmos. Chem. Phys. Discuss., 15, 4427-4461, doi:10.5194/acpd-15-4427-2015, 2015
Impact of the 2009 major stratospheric sudden warming on the composition of the stratosphere
Summary: A remarkable Major stratospheric sudden Warming (MW) during the boreal winter 2008/09 is studied with the Chemical Lagrangian Model of the Stratosphere (CLaMS). We investigate 1) how mixing triggered by this event correlates the wave forcing and 2) how transport and mixing affect the composition of the whole stratosphere in the northern hemisphere by using the tracer-tracer correlation technique.
Atmos. Chem. Phys. Discuss., 15, 4383-4426, doi:10.5194/acpd-15-4383-2015, 2015
Global distributions of overlapping gravity waves in HIRDLS data
Summary: Data from the HIRDLS instrument are used to study the numerical variability of gravity waves. Observed distributions are dominated by long-vertical-short-horizontal-wavelength waves, with a similar spectral form at all locations. We further divide our data into subspecies by wavelength, and investigate variation of these subspecies in time and space. We show that the variations associated with particular phenomena arise due to changes in specific parts of the spectrum.
Atmos. Chem. Phys. Discuss., 15, 4333-4382, doi:10.5194/acpd-15-4333-2015, 2015
Data assimilation of satellite retrieved ozone, carbon monoxide and nitrogen dioxide with ECMWF's Composition-IFS
Summary: The paper presents results from data assimilation studies with the new Composition-IFS model developed in the MACC project. This system was used in MACC to produce daily analyses and 5-day forecasts of atmospheric composition and is now run daily in the EU’s Copernicus Atmosphere Monitoring Service. The paper looks at the quality of the CO, O3 and NO2 analysis fields obtained with this system comparing them against observations, a control run and an older version of the model.
Atmos. Chem. Phys. Discuss., 15, 4265-4331, doi:10.5194/acpd-15-4265-2015, 2015
Model studies of volatile diesel exhaust particle formation: organic vapours involved in nucleation and growth?
Atmos. Chem. Phys. Discuss., 15, 4219-4263, doi:10.5194/acpd-15-4219-2015, 2015
Investigating the frequency and trends in global above-cloud aerosol characteristics with CALIOP and OMI
Summary: The spatial distributions and trends of aerosol above cloud (ACA) events are studied using seven and a half years of MODIS, OMI and CALIOP data. The active- (CALIOP) and passive-based (MODIS-OMI) methods have their advantages and caveats, and thus both are used to get a thorough and robust comparison of ACA distribution and climatology. For the first time, baseline above cloud CALIOP aerosol optical depth and OMI aerosol index thresholds are derived and examined for each sensor.
Atmos. Chem. Phys. Discuss., 15, 4173-4217, doi:10.5194/acpd-15-4173-2015, 2015
Impact of gas-to-particle partitioning approaches on the simulated radiative effects of biogenic secondary organic aerosol
Summary: To understand the radiative effects of biogenic secondary organic aerosol (SOA) it is necessary to consider the manner in which it is distributed across the existing aerosol size distribution. We explore the importance of the approach taken by global-scale models to do this, when calculating the direct radiative effect (DRE) & first aerosol indirect effect (AIE) due to biogenic SOA. This choice has little effect on the DRE, but a substantial impact on the magnitude and even sign of the first AIE
Atmos. Chem. Phys. Discuss., 15, 4145-4172, doi:10.5194/acpd-15-4145-2015, 2015
Formation of hydroxyl radicals from photolysis of secondary organic aerosol material
Summary: This is the first paper to demonstrate that SOA material forms OH radicals upon UV illumination. We quantify the OH formation rates in solution and show species other than H2O2, mostly probably ROOH molecules, are the likely source of the OH. The importance of an OH source from SOA is that photochemical processing within both cloudwater and aerosol particles may arise subsequent to the formation of these radicals.
Atmos. Chem. Phys. Discuss., 15, 4117-4143, doi:10.5194/acpd-15-4117-2015, 2015
Regional differences in Chinese SO2 emission control efficiency and policy implications
Summary: We found that SO2 emission reduction over NC is most effective in reducing national-mean surface sulfate concentrations and sulfur export fluxes, with β being 0.76 and 0.95 respectively, while SO2 emission reduction over SC has the highest β in reducing PWC (β = 0.98). The policy implication is that China needs to carefully design a regionally specific implementation plan of realizing its SO2 emissions reduction target in order to maximize the resulting air quality benefits .
Atmos. Chem. Phys. Discuss., 15, 4083-4115, doi:10.5194/acpd-15-4083-2015, 2015
Survival and ice nucleation activity of bacteria as aerosols in a cloud simulation chamber
Summary: - We determined mortality rate of typical bacterial aerosols (Pseudomonas species) - Ice nucleation activity remained unchanged for several hours in aerosolized cells, whether they were viable or not - Cloud increased the specific removal of ice nucleation active cells by precipitation - Survival was impacted by the presence of cloud and by sulfates
Atmos. Chem. Phys. Discuss., 15, 4055-4082, doi:10.5194/acpd-15-4055-2015, 2015
Statistical exploration of gaseous elemental mercury (GEM) measured at Cape Point from 2007 to 2011
Summary: Statistical techniques applied to continuous high-resolution Hg data and back-trajectory analyses showed lower GEM concentrations originating from the sparsely populated semi-arid interior of SA and the marine environment, whereas higher GEM concentrations coincided with trade routes and industrial activities along the coast. Multi-linear regression indicated the relation of GEM with other atmospheric parameters. Measured and MLR data confirm a decline in GEM concentrations at CPT GAW station.
Atmos. Chem. Phys. Discuss., 15, 4025-4053, doi:10.5194/acpd-15-4025-2015, 2015
Technical Note: Optical properties of desert dust with non-spherical particles: data incorporated to OPAC
Summary: Desert dust particles in general are not spherical, which changes their scattering functions against that for spheres that often are used for remote sensing and radiation budget investigations. In the new version of the data base OPAC (Optical Properties of Aerosols and Clouds), which easily allows one to model a large range of microphysical and optical aerosol properties for individually decided component mixtures, now typical non-spherical mineral particles are taken into account.
Atmos. Chem. Phys. Discuss., 15, 3995-4023, doi:10.5194/acpd-15-3995-2015, 2015
Wind extraction potential from ensemble Kalman filter assimilation of stratospheric ozone using a global shallow water model
Summary: While direct wind observations are routinely made in the troposphere (0-10 km), in the stratosphere (above 10 km) wind observations are sparse. This study examines the potential of using ozone observations to infer stratospheric wind. This novel approach is tested with a data assimilation system based on a simplified model of the atmosphere, the so-called "shallow water model". It is shown that assimilation of ozone observations significantly benefits winds, particularly in the tropics
Atmos. Chem. Phys. Discuss., 15, 3955-3994, doi:10.5194/acpd-15-3955-2015, 2015
Vertical profiles of optical and microphysical particle properties above the northern Indian Ocean during CARDEX 2012
Summary: The paper presents aerosol properties measured during the Cloud Aerosol Radiative Forcing Experiment (CARDEX) on the Maldives Islands in winter 2012. The vertical distribution of absorbing aerosol which is very relevant to the radiative forcing in that region, is investigated. A method for determining particle absorption and equivalent black carbon concentration from Lidar extinction measurements, characteristic single scattering albedo and mass absorption efficiency, is presented and evaluated.
Atmos. Chem. Phys. Discuss., 15, 3907-3953, doi:10.5194/acpd-15-3907-2015, 2015
On the competition among aerosol number, size and composition in predicting CCN variability: a multi-annual field study in an urbanized desert
Atmos. Chem. Phys. Discuss., 15, 3863-3906, doi:10.5194/acpd-15-3863-2015, 2015
Climate responses to anthropogenic emissions of short-lived climate pollutants
Atmos. Chem. Phys. Discuss., 15, 3823-3862, doi:10.5194/acpd-15-3823-2015, 2015
Successes and challenges of measuring and modeling atmospheric mercury at the part per quadrillion level: a critical review
Summary: The Minamata Convention for mercury (Hg) has been signed by many nations and the primary objective is to protect human health and the environment from releases of Hg. A key challenge researchers is developing linkages between Hg in the atmosphere, deposition, and ecosystem contamination. Here we critically review where the science on measuring and modeling atmospheric Hg stands and offer suggestions for future research that will both advance understanding of Hg cycling and serve the Convention.
Atmos. Chem. Phys. Discuss., 15, 3777-3821, doi:10.5194/acpd-15-3777-2015, 2015
Modeling study of PM2.5 pollutant transport across cities in China's Jing–Jin–Ji region during a severe haze episode in December 2013
Atmos. Chem. Phys. Discuss., 15, 3745-3776, doi:10.5194/acpd-15-3745-2015, 2015
Water soluble aerosols and gases at a UK background site – Part 1: Controls of PM2.5 and PM10 aerosol composition
Summary: Hourly inorganic composition of UK background particulate matter (PM10 and PM2.5) has been studied for a 6.5 year period at Auchencorth Moss, Scotland. Long range transport of both anthropogenic secondary and natural primary PM is observed, driven primarily by meteorology. The importance of nitrate, sulphate and ammonium during pollution events in the UK is demonstrated.
Atmos. Chem. Phys. Discuss., 15, 3703-3743, doi:10.5194/acpd-15-3703-2015, 2015
Experimental investigation of ion-ion recombination at atmospheric conditions
Summary: The ion-ion recombination coefficient was measured at different temperatures, relative humidities and concentrations of ozone and sulfur dioxide. The experiments were carried out using the CLOUD chamber at CERN. We observed a strong dependency on temperature and on relative humidity, which has not been reported previously. No dependency of the ion-ion recombination coefficient on ozone concentration and a weak variation with sulfur dioxide concentration were also observed.
Atmos. Chem. Phys. Discuss., 15, 3667-3702, doi:10.5194/acpd-15-3667-2015, 2015
Peroxynitric acid (HO2NO2) measurements during the UBWOS 2013 and 2014 studies using iodide ion chemical ionization mass spectrometry
Atmos. Chem. Phys. Discuss., 15, 3629-3666, doi:10.5194/acpd-15-3629-2015, 2015
Predicting the mineral composition of dust aerosols – Part 2: Model evaluation and identification of key processes with observations
Summary: A global compilation from nearly sixty measurement studies is used to evaluate two methods of simulating the mineral composition of dust aerosols. Dust emission based on wet-sieved soil is assumed for the first method. The second method reconstructs the aggregates and size distribution of the original soil before emission. Only the second method is able to reproduce observed phyllosilicate fractions in the silt size range and reduces quartz overestimation. Substantial uncertainties remain.
Atmos. Chem. Phys. Discuss., 15, 3577-3627, doi:10.5194/acpd-15-3577-2015, 2015
Predicting the mineral composition of dust aerosols – Part 1: Representing key processes
Summary: The mineral composition of dust aerosols is modeled. The mineral composition is derived by extending a method that provides the composition of wet-sieved soil to account for differences between the mineral fractions of the wet-sieved soil and the resulting aerosol concentration. An empirical constraint upon the relative emission of clay and silt is applied that further differentiates soil and aerosol mineral composition. A method is proposed for mixing minerals with iron oxide impurities.
Atmos. Chem. Phys. Discuss., 15, 3493-3575, doi:10.5194/acpd-15-3493-2015, 2015
Sources and chemical characterization of organic aerosol during the summer in the eastern Mediterranean
Atmos. Chem. Phys. Discuss., 15, 3455-3491, doi:10.5194/acpd-15-3455-2015, 2015
Increasing and decreasing trends of the atmospheric deposition of organochlorine compounds in European remote areas during the last decade
Summary: Despite the regulations in the use of polychlorobiphenyls (PCBs), an increase in atmospheric deposition fluxes of these pollutants in high altitude mountain areas of Europe is observed for the period between 1996 and 2006. In contrast, atmospheric deposition of organochlorine pesticides showed a strong decrease. Volatilization from soils or melting glaciers related to climate change and the differences in physical-chemical properties between compounds may explain the observed temporal trend.
Atmos. Chem. Phys. Discuss., 15, 3415-3453, doi:10.5194/acpd-15-3415-2015, 2015
Vertical variation of optical properties of mixed Asian dust/pollution plumes according to pathway of airmass transport over East Asia
Summary: The measurements from 2009 to 2013 by using a multiwavelength Raman lidar were conducted to identify the changes of optical properties of East Asian dust. We found that the optical properties of Asian dust change in dependence of the dust plume's vertical position and the change of vertical position during transport over China. We believe this paper provides a better understanding of the optical properties of mixed Asian dust plums and the effect of long-range transport on dust properties.
Atmos. Chem. Phys. Discuss., 15, 3381-3413, doi:10.5194/acpd-15-3381-2015, 2015
Low hygroscopic scattering enhancement of boreal aerosol and the implications for a columnar optical closure study
Atmos. Chem. Phys. Discuss., 15, 3327-3379, doi:10.5194/acpd-15-3327-2015, 2015
Impacts of atmospheric circulations on aerosol distributions in autumn over eastern China: observational evidences
Summary: We systematically examined that how various large scale atmospheric conditions (ACs) affects the distributions of aerosol optical depth over the East China.We extract and depict nine main types for ACs-effect AOD (six polluted types and three clean types) in autumn over East China. The results provide convincing evidences that the general characteristics of atmospheric circulations contribute significantly to the different types of regional pollution.
Atmos. Chem. Phys. Discuss., 15, 3285-3325, doi:10.5194/acpd-15-3285-2015, 2015
Black carbon emissions from Russian diesel sources: case study of Murmansk
Summary: We estimated BC emissions from diesel sources in Murmansk Region and Murmansk City, the largest city in the Arctic. We developed a detailed inventory including on-road vehicles, off-road transport (mining, locomotives, construction and agriculture), fishing and diesel generators. We conducted several surveys to understand the vehicle fleet and driving patterns. BC emissions in Murmansk Region were 0.40 Gg in 2012. Total BC emissions from diesel sources in Russia estimated at 56.7 Gg in 2010.
Atmos. Chem. Phys. Discuss., 15, 3257-3284, doi:10.5194/acpd-15-3257-2015, 2015
Evaluation of updated nitric acid chemistry on ozone precursors and radiative effects
Atmos. Chem. Phys. Discuss., 15, 3219-3255, doi:10.5194/acpd-15-3219-2015, 2015
The southern stratospheric gravity-wave hot spot: individual waves and their momentum fluxes measured by COSMIC GPS-RO
Atmos. Chem. Phys. Discuss., 15, 3173-3217, doi:10.5194/acpd-15-3173-2015, 2015
In situ vertical profiles of aerosol extinction, mass, and composition over the southeast United States during SENEX and SEAC4RS: observations of a modest aerosol enhancement aloft
Summary: This paper investigates the summertime vertical profile of aerosol over the southeastern US using in situ measurements collected from aircraft. We use a vertical mixing model and measurements of CO to predict the vertical profile of aerosol that we would expect from vertical mixing alone and compare with the observed aerosol profile. We found a modest enhancement of aerosol in the cloudy transition layer during shallow cumulus convection and attribute the enhancement to local aerosol formation.
Atmos. Chem. Phys. Discuss., 15, 3127-3172, doi:10.5194/acpd-15-3127-2015, 2015
Ozone and aerosols tropospheric concentrations variability analyzed using the ADRIMED measurements and the WRF-CHIMERE models
Summary: The ozone and aerosols concentrations variability is studied over the Euro-Mediterranean area during the months of June and July 2013 and in the framework of the ADRIMED project. A first analysis is performed using meteorological variables, ozone and aerosols concentrations using routine stations network, satellite and specific ADRIMED project airborne measurements. This analysis is complemented by modelling using the WRF and CHIMERE regional models.
Atmos. Chem. Phys. Discuss., 15, 3063-3125, doi:10.5194/acpd-15-3063-2015, 2015
CFD modeling of a vehicle exhaust laboratory sampling system: sulfur driven nucleation and growth in diluting diesel exhaust
Summary: This article presents a new model that simulates particle formation in vehicle exhaust. The model is used to examine particle dynamics, such as nucleation, inside a diesel exhaust laboratory sampling system. The results suggest lower slope of nucleation rate versus sulfuric acid concentration than previously found.
Atmos. Chem. Phys. Discuss., 15, 2905-2956, doi:10.5194/acpd-15-2905-2015, 2015
Observations of relative humidity effects on aerosol light scattering in the Yangtze River Delta of China
Summary: The aerosol hygroscopic properties at a rural background site in the Yangtze River Delta of China was discussed. The result shows the scattering coefficient and backscattering coefficient increased by 58% and 25% as relative humidity (RH) increased from 40% to 85%; while the hemispheric backscatter fraction decreased by 21%. Aerosol direct forcing increased by 16% at ambient mean RH of 67% due to the water uptake at LinAn in March,2013. Nitrate played a vital role in the aerosol hygroscopicity.
Atmos. Chem. Phys. Discuss., 15, 2853-2904, doi:10.5194/acpd-15-2853-2015, 2015
The relationship between cloud condensation nuclei (CCN) concentration and light extinction of dried particles: indications of underlying aerosol processes and implications for satellite-based CCN estimates
Atmos. Chem. Phys. Discuss., 15, 2745-2789, doi:10.5194/acpd-15-2745-2015, 2015
An ecosystem-scale perspective of the net land methanol flux: synthesis of micrometeorological flux measurements
Summary: Methanol is the second most abundant volatile organic compound in the troposphere and plays a significant role in atmospheric chemistry. While there is consensus about the dominant role of plants as the major source and the reaction with OH as the major sink, global methanol budgets diverge considerably in terms of source/sink estimates. Here we present micrometeorological methanol flux data from eight 8 sites in order to provide a first cross-site synthesis of the terrestrial methanol exchange.
Atmos. Chem. Phys. Discuss., 15, 2577-2613, doi:10.5194/acpd-15-2577-2015, 2015
Stratosphere–troposphere exchange (STE) in the vicinity of North Atlantic cyclones
Summary: In this manuscript, we investigate the exchange of air masses across the dynamical tropopause (stratosphere-troposphere exchange, STE) in the vicinity of North Atlantic cyclones. By using two 6-hourly resolved ERA-Interim climatologies of STE and cyclones from 1979 to 2011, we are able to directly compute the amount of STE in the vicinity of every individual cyclone in this time period. This enables us to provide a robust and consistent quantification of STE near North Atlantic cyclones.
Atmos. Chem. Phys. Discuss., 15, 2535-2575, doi:10.5194/acpd-15-2535-2015, 2015
Assessment of crop yield losses in Punjab and Haryana using two years of continuous in-situ ozone measurements
Summary: We use ozone measurements at a suburban site in Punjab to estimated ozone related crop yield losses for wheat, rice, cotton and maize for the states Punjab and Haryana for the years 2011-2013. Crop production losses amount to 10.3-20.8 Mt y-1 for wheat & 3.2-5.4 Mt y-1 for rice enough to feed 225-437 million of India’s poor. The lower limit for the ozone related economic losses is 3.7-6.5 billion USD (Punjab & Haryana), while the upper limit amounts to 3.5%-20% of the Indian GDP (entire India).
Atmos. Chem. Phys. Discuss., 15, 2355-2404, doi:10.5194/acpd-15-2355-2015, 2015
LIVAS: a 3-D multi-wavelength aerosol/cloud climatology based on CALIPSO and EARLINET
Atmos. Chem. Phys. Discuss., 15, 2247-2304, doi:10.5194/acpd-15-2247-2015, 2015
Effects of global change during the 21st century on the nitrogen cycle
Atmos. Chem. Phys. Discuss., 15, 1747-1868, doi:10.5194/acpd-15-1747-2015, 2015
Deposition and immersion mode nucleation of ice by three distinct samples of volcanic ash using Raman spectroscopy
Summary: Fine volcanic ash can influence cloud glaciation and, therefore, global climate. In this work we examined the heterogeneous ice nucleation properties of three distinct types of volcanic ash. We find that, in contrast to previous studies, these volcanic ash samples have different ice nucleation properties in the immersion mode. In the deposition mode, however, they nucleate ice with similar efficiency. We show that this behavior may be due to their mineralogy.
Atmos. Chem. Phys. Discuss., 15, 1385-1420, doi:10.5194/acpd-15-1385-2015, 2015
Technical Note: A novel parameterization of the transmissivity due to ozone absorption in the k-distribution method and correlated-k approximation of Kato et al. (1999) over the UV band
Summary: A novel model of the absorption of radiation by ozone in the UV bands [283, 307] nm and [307, 328] nm yields improvements in the modelling of the transmissivity in these bands. This model is faster than detailed spectral calculations and is as accurate with maximum error of respectively 0.0006 and 0.0041. How to practically implement this new parameterization in a radiative transfer model is discussed for the case of libRadtran.
Atmos. Chem. Phys. Discuss., 15, 1027-1040, doi:10.5194/acpd-15-1027-2015, 2015
A modified micrometeorological gradient method for estimating O3 dry deposition over a forest canopy
Summary: In this study, we have developed a modified micrometeorological gradient method (MGM), although based on existing micrometeorological theory, to estimate O3 dry deposition fluxes over a forest canopy using concentration gradients between a level above and a level below the canopy top. The new method provides an alternative approach in monitoring/estimating long-term deposition fluxes of similar pollutants over tall canopies and is expected to be useful for the scientific community.
Atmos. Chem. Phys. Discuss., 15, 779-806, doi:10.5194/acpd-15-779-2015, 2015
Particulate matter, air quality and climate: lessons learned and future needs
Summary: Particulate matter (PM) constitutes one of the most challenging problems both for air quality and climate change policies. This paper reviews the most recent scientific results on the issue, and the policy needs that have driven much of the increase in monitoring and mechanistic research over the last two decades. The synthesis reveals many new processes and developments in the science underpinning climate-PM interactions and effects of PM on human health and the environment.
Atmos. Chem. Phys. Discuss., 15, 521-744, doi:10.5194/acpd-15-521-2015, 2015
Volatile organic compounds over Eastern Himalaya, India: temporal variation and source characterization using Positive Matrix Factorization
Atmos. Chem. Phys. Discuss., 14, 32133-32175, doi:10.5194/acpd-14-32133-2014, 2014
Formaldehyde (HCHO) in air, snow and interstitial air at Concordia (East Antarctic plateau) in summer
Summary: During two austral summers HCHO was investigated in air, snow, and interstitial air at the Concordia site located on the East Antarctic plateau. Snow emission fluxes were estimated to be around 1 to 2 and 3 to 5 x 1012 molecules m-2 s-1 at night and at noon, respectively. Shading experiments suggest that the photochemical HCHO production in the snowpack at Concordia remains negligible. The mean HCHO level of 130 pptv observed at 1 m above the surface, is quite well reproduced by 1-D simulations.
Atmos. Chem. Phys. Discuss., 14, 32027-32070, doi:10.5194/acpd-14-32027-2014, 2014
Particulate emissions from residential wood combustion in Europe – revised estimates and an evaluation
Summary: Residential wood combustion (RWC) is increasing in Europe but may cause high emissions of particulate matter (PM). A new bottom-up emission inventory for RWC was made which included the semi-volatile components. The new RWC emissions are 2-3 times higher than the previous inventory. It significantly improved the modeling of PM and comparison with observations. Our results suggest primary PM2.5 emission from RWC as reported in Europe is underestimated and emission inventories need to be revised.
Atmos. Chem. Phys. Discuss., 14, 31719-31765, doi:10.5194/acpd-14-31719-2014, 2014
A global model simulation for 3-D radiative transfer impact on surface hydrology over Sierra Nevada and Rocky Mountains
Summary: This paper investigates 3-D mountain effects on solar flux distributions and their impact on surface hydrology over the Western United States, specifically the Rocky Mountains and Sierra Nevada using CCSM4 (CAM4/CLM4) global model with a 0.23°×0.31° resolution for simulations over 6 years. We show that deviations of the net surface fluxes are not only affected by 3-D mountains, but also influenced by feedbacks of cloud and snow in association with the long-term simulations.
Atmos. Chem. Phys. Discuss., 14, 31603-31625, doi:10.5194/acpd-14-31603-2014, 2014
Estimates of non-traditional secondary organic aerosols from aircraft SVOC and IVOC emissions using CMAQ
Summary: Utilizing an aircraft-specific parameterization based on smog chamber data in a regional AQM, contributions of non-traditional secondary organic aerosols (NTSOA) from aircraft emissions of semi-volatile and intermediate volatility organic compounds were assessed. NTSOA, a previously unaccounted component of PM2.5 in most AQMs, contributed up to 7.4% of aviation-attributable PM2.5 at the airport, and rose to 17.9% downwind, suggesting its significance in aviation-attributed PM2.5 at all scales.
Atmos. Chem. Phys. Discuss., 14, 30667-30703, doi:10.5194/acpd-14-30667-2014, 2014
Evaluating BC and NOx emission inventories for the Paris region from MEGAPOLI aircraft measurements
Atmos. Chem. Phys. Discuss., 14, 29237-29304, doi:10.5194/acpd-14-29237-2014, 2014
Interactions of bromine, chlorine, and iodine photochemistry during ozone depletions in Barrow, Alaska
Atmos. Chem. Phys. Discuss., 14, 28685-28755, doi:10.5194/acpd-14-28685-2014, 2014
Ice nucleation terminology
Atmos. Chem. Phys. Discuss., 14, 22155-22162, doi:10.5194/acpd-14-22155-2014, 2014