A solar signal in lower stratospheric water vapour?
Summary: A merged data set of HALOE and MIPAS lower stratospheric water vapour has been constructed. Multivariate linear regression yields that the merged time series can best be explained if a proxy for the 11-year solar cycle is considered. The amplitude of the solar cycle signal in water vapour is slightly higher than that which can be explained by the known solar cycle variation of cold-point temperatures.
Atmos. Chem. Phys. Discuss., 15, 12353-12387, doi:10.5194/acpd-15-12353-2015, 2015
Diurnal cycle of the dust instantaneous direct radiative forcing over the Arabian Peninsula
Summary: Calculate radiative effect of dust over different surfaces and for different optical depth, and test it using satellite and ground-based observations
Atmos. Chem. Phys. Discuss., 15, 12301-12352, doi:10.5194/acpd-15-12301-2015, 2015
Diurnal, seasonal and long-term variations of global formaldehyde columns inferred from combined OMI and GOME-2 observations
Summary: We present the new version of the BIRA-IASB algorithm for the retrieval of H2CO columns from OMI and GOME-2A and B measurements. Validation results at seven stations in Europe, China and Africa confirm the capacity of the satellite measurements to resolve diurnal variations in H2CO columns. Furthermore, vertical profiles derived from MAX-DOAS measurements in Beijing and in Bujumbura are used for a more detailed validation exercise. Finally trends are estimated using 10 years of OMI observations.
Atmos. Chem. Phys. Discuss., 15, 12241-12300, doi:10.5194/acpd-15-12241-2015, 2015
An algorithm for the numerical solution of the multivariate master equation for stochastic coalescence
Summary: The mathematical description of finite volume coalescing systems relies on the multivariate master equation. However, due to its complexity, it has analytical solutions only for a limited number of kernels and initial conditions. In this paper, in an effort to solve this problem, we have introduced a novel numerical approach to calculate the solution of the multivariate coalescence master equation that works for any type of kernels and initial conditions.
Atmos. Chem. Phys. Discuss., 15, 12213-12240, doi:10.5194/acpd-15-12213-2015, 2015
Estimating collision efficiencies from contact freezing experiments
Summary: We determined experimentally collision efficiencies of cloud droplets with aerosol particles and found that they were around one order of magnitude higher than theoretical formulations that include Brownian diffusion, impaction, interception, thermophoretic, diffusiophoretic and electric forces, most probably due to uncertainties and inaccuracies in the theoretical formulations of thermophoretic and diffusiophoretic processes.
Atmos. Chem. Phys. Discuss., 15, 12167-12212, doi:10.5194/acpd-15-12167-2015, 2015
Quantitative assessment of atmospheric emissions of toxic heavy metals from anthropogenic sources in China: historical trend, spatial variation distribution, uncertainties and control policies
Summary: For the first time, with S-shaped curves, the best available representation of time-varying emission factors of 12 heavy metals (Hg, As, Se, Pb, Cd, Cr, Ni, Sb, Mn, Co, Cu and Zn) from primary anthropogenic sources of China are determined on accounting of economic transitions and pollution control technology improvement, and the temporal and spatial variation characteristics of these heavy metals emissions during the period of 1949−2012 are calculated and evaluated with uncertainty analysis.
Atmos. Chem. Phys. Discuss., 15, 12107-12166, doi:10.5194/acpd-15-12107-2015, 2015
Use of criteria pollutants, active and passive mercury sampling, and receptor modeling to understand the chemical forms of gaseous oxidized mercury in Florida
Summary: Gaseous oxidized Hg (GOM) is a major contributor to Hg in wet and dry deposition. Recent work has indicated that the concentrations of GOM as measured are too low by 3-to-12 times; and that compounds vary across space and time. Data collected in Florida indicate five potential GOM compounds, including HgBr2, HgO, Hg(NO3)2, HgSO4, and an unknown compound. Sources include local combustion (cars and power plants), the marine boundary layer, and long range transport from Asia.
Atmos. Chem. Phys. Discuss., 15, 12069-12105, doi:10.5194/acpd-15-12069-2015, 2015
How consistent are top-down hydrocarbon emissions based on formaldehyde observations from GOME-2 and OMI?
Atmos. Chem. Phys. Discuss., 15, 12007-12067, doi:10.5194/acpd-15-12007-2015, 2015
The role of blowing snow in the activation of bromine over first-year Antarctic sea ice
Summary: This work analyzes the chemical composition of blowing snow collected over 1st-year Antarctic sea ice to assess its role in bromine activation during the polar sunrise. We found lofted snow to be depleted in Br- relative to Cl- by proportionally increasing amounts with height. This is the first study to use field data to substantiate modeling results implicating blowing snow as the location for initial halogen activation. We also found lofted snow to be depleted in SO4 and enriched in NO3.
Atmos. Chem. Phys. Discuss., 15, 11985-12005, doi:10.5194/acpd-15-11985-2015, 2015
Observations of atmospheric mercury in China: a critical review
Atmos. Chem. Phys. Discuss., 15, 11925-11983, doi:10.5194/acpd-15-11925-2015, 2015
On the statistical optimality of CO2 atmospheric inversions assimilating CO2 column retrievals
Summary: We demonstrate that a two-step approach to infer the CO2 surface fluxes from satellite measured radiances, with CO2 retrievals as an intermediate product, cannot be optimal. This suboptimality corrupts the 4D information flow from the radiance measurements to the surface flux estimates. It is amplified by current retrieval strategies where prior errors are much larger than the performance of prior CO2 simulations used in atmospheric inversions. We use the ACOS-GOSAT retrievals as an example and
Atmos. Chem. Phys. Discuss., 15, 11889-11923, doi:10.5194/acpd-15-11889-2015, 2015
Sensitivity of the recent methane budget to LMDz sub-grid scale physical parameterizations
Atmos. Chem. Phys. Discuss., 15, 11853-11888, doi:10.5194/acpd-15-11853-2015, 2015
Solar geoengineering using solid aerosol in the stratosphere
Summary: We investigate stratospheric aerosol geoengineering with solid particle injection by modeling the fractal structure of alumina aerosols and their interaction with background sulfate. We analyze the efficacy (W m^-2 of radiative forcing per megaton of injection) and risks (ozone loss) for both alumina and diamond particles as a function of injected monomer radius, finding 240 nm alumina and 160 nm diamond optimal. We discuss the limitations of our 2-D model study and associated uncertainties.
Atmos. Chem. Phys. Discuss., 15, 11799-11851, doi:10.5194/acpd-15-11799-2015, 2015
Relationships between photosynthesis and formaldehyde as a probe of isoprene emission
Summary: We apply two global observational datasets: gross primary productivity (GPP) and tropospheric formaldehyde column variability (HCHOv) to probe isoprene emission variability on large spatiotemporal scales. GPP and HCHOv are decoupled or weakly anti-correlated in regions and seasons when isoprene emission is high. Isoprene emission models that include soil moisture dependence demonstrate greater skill in reproducing observed seasonal GPP-HCHOv correlations in the southeast US and the Amazon.
Atmos. Chem. Phys. Discuss., 15, 11763-11797, doi:10.5194/acpd-15-11763-2015, 2015
The role of ice nuclei recycling in the maintenance of cloud ice in Arctic mixed-phase stratocumulus
Atmos. Chem. Phys. Discuss., 15, 11727-11761, doi:10.5194/acpd-15-11727-2015, 2015
The Amazon Tall Tower Observatory (ATTO) in the remote Amazon Basin: overview of first results from ecosystem ecology, meteorology, trace gas, and aerosol measurements
Summary: This paper describes the Amazon Tall Tower Observatory (ATTO), a new atmosphere-biosphere observatory located in the remote Amazon Basin. It presents results from ecosystem ecology, meteorology, trace gas, and aerosol measurements collected at the ATTO site during the first three years of operation.
Atmos. Chem. Phys. Discuss., 15, 11599-11726, doi:10.5194/acpd-15-11599-2015, 2015
Impact of ozone observations on the structure of a tropical cyclone using coupled atmosphere–chemistry data assimilation
Summary: In this study, the impact of O3 observations on the tropical cyclone (TC) structure is examined using the WRF-Chem with an ensemble-based data assimilation (DA) system. For a TC case that occurred over the East Asia, the ensemble forecast is reasonable and the O3 assimilation affects both chemical and atmospheric variables near the TC area. All measures indicate a positive impact of DA on the analysis – the cost function and root mean square error have decreased by 16.9% and 8.87%, respectively.
Atmos. Chem. Phys. Discuss., 15, 11573-11597, doi:10.5194/acpd-15-11573-2015, 2015
Effects of mineral dust on global atmospheric nitrate concentrations
Summary: We provide an assessment of the chemical composition and global aerosol load of aerosol nitrate and determine the effect of mineral dust on its formation due to thermodynamical interactions. For this purpose we used an explicit geographical representation of the emitted soil particle size distribution and chemical composition. We conclude that mineral dust aerosol chemistry is important for nitrate aerosol formation and significantly affects its global distribution, especially in the coarse mode
Atmos. Chem. Phys. Discuss., 15, 11525-11572, doi:10.5194/acpd-15-11525-2015, 2015
Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China during summertime
Atmos. Chem. Phys. Discuss., 15, 11495-11524, doi:10.5194/acpd-15-11495-2015, 2015
Atmospheric black carbon and sulfate concentrations in Northeast Greenland
Summary: Aerosols particles reach via long-range transport the high Arctic and have significant impacts on Arctic climate. This article demonstrates the comparison of measured and modelled aerosol mass concentrations for black carbon and sulfate particles at a high Arctic site. Based on the findings aging processes during transport seem to prolong the lifetimes of the two species and favor the possibility for their transport to the high Arctic.
Atmos. Chem. Phys. Discuss., 15, 11465-11493, doi:10.5194/acpd-15-11465-2015, 2015
Quantifying the contribution of long-range transport to Particulate Matter (PM) mass loadings at a suburban site in the North-Western Indo Gangetic Plain (IGP)
Summary: We quantify the contribution of long range transport to PM levels in the NW-IGP through back trajectory climatology analysis. Transport from the west significantly enhanced coarse and fine mode PM mass loadings during all seasons. Local pollution episodes enhanced coarse mode PM only during winter and fine mode PM during winter and summer season. South easterly air masses (Source region: SE-IGP) were associated with significantly lower fine and coarse mode PM mass loadings during all seasons.
Atmos. Chem. Phys. Discuss., 15, 11409-11464, doi:10.5194/acpd-15-11409-2015, 2015
Use of North American and European air quality networks to evaluate global chemistry-climate modeling of surface ozone
Summary: We test global-chemistry-climate models in their ability to simulate present-day surface ozone. Models are tested against observed hourly ozone from 4,217 stations in N. America and Europe that are averaged over 1°x1° grid cells. Using novel metrics, we find most models match the shape but not the amplitude of regional summertime diurnal and annual cycles and match the pattern but not the magnitude of summer ozone enhancement. Most also match the observed distribution of extreme episode sizes.
Atmos. Chem. Phys. Discuss., 15, 11369-11407, doi:10.5194/acpd-15-11369-2015, 2015
The impact of shipping emissions on air pollution in the Greater North Sea region – Part 2: Scenarios for 2030
Summary: Scenarios for future shipping emissions in the North Sea were developed. Compared to today, the contribution of shipping to the nitrogen dioxide and ozone concentrations will increase due to the expected enhanced traffic by more than 20% and 5%, respectively, by 2030 if no regulation for further emission reductions will be implemented. PM2.5 will decrease slightly because the sulphur contents in ship fuels will be reduced.
Atmos. Chem. Phys. Discuss., 15, 11325-11368, doi:10.5194/acpd-15-11325-2015, 2015
The impact of shipping emissions on air pollution in the Greater North Sea region – Part 1: Current emissions and concentrations
Summary: A multi-model approach consisting of a bottom-up ship emissions model and a chemistry transport model was used to evaluate the impact of shipping on air quality in North Sea bordering countries. As an example, the results of the simulations indicated that the relative contribution of ships to NO2 concentration levels ashore close to the sea can reach up to 25% in summer and 15% in winter. Some hundred kilometers away from the sea the contribution was about 6% in summer and 4% in winter.
Atmos. Chem. Phys. Discuss., 15, 11277-11323, doi:10.5194/acpd-15-11277-2015, 2015
Characterization of a real-time tracer for Isoprene Epoxydiols-derived Secondary Organic Aerosol (IEPOX-SOA) from aerosol mass spectrometer measurements
Atmos. Chem. Phys. Discuss., 15, 11223-11276, doi:10.5194/acpd-15-11223-2015, 2015
Comparison of the CMAM30 data set with ACE-FTS and OSIRIS: polar regions
Summary: The CMAM30 data set takes a chemistry-climate model and relaxes the dynamics to reanalysis, which can then provide chemistry fields not available from the reanalysis data set. This paper addresses this gap by comparing temperature, water vapour, ozone and methane to satellite data to determine and document any biases in the model fields. The lack of ozone destruction and dehydration in the SH polar vortex is shown to be due to the treatment of polar stratosphere clouds in the model.
Atmos. Chem. Phys. Discuss., 15, 11179-11221, doi:10.5194/acpd-15-11179-2015, 2015
Atmospheric new particle formation as source of CCN in the Eastern Mediterranean marine boundary layer
Summary: Cloud Condensation Nuclei (CCN) production associated with atmospheric new particle formation (NPF) is presented and this is the first direct evidence on CCN production resulting from NPF in the Eastern Mediterranean atmosphere. We show that condensation of both gaseous sulfuric acid and organic compounds from multiple sources leads to the rapid growth of nucleated particles. Sub-100nm particles were found to be substantially less hygroscopic than larger particles during the active NPF period
Atmos. Chem. Phys. Discuss., 15, 11143-11178, doi:10.5194/acpd-15-11143-2015, 2015
Heavy air pollution episodes in Beijing during January 2013: inorganic ion chemistry and source analysis using Highly Time-Resolved Measurements in an urban site
Summary: This paper focused on the air pollution episodes occurred in Beijing, China, during January of 2013. Highly time-resolved measurements of water soluble ions associated with PM2.5 were conducted at an urban site. The paper analyzed the potential roles of water-soluble ions in the formation of air pollution episodes, and found sulfate might be one of the key factors in episodes by analyzing ions compositions in different PM2.5 concentrations.
Atmos. Chem. Phys. Discuss., 15, 11111-11141, doi:10.5194/acpd-15-11111-2015, 2015
Multi-model evaluation of short-lived pollutant distributions over East Asia during summer 2008
Summary: This paper evaluate the ability of 6 global and one regional models in reproducing short-lived pollutants (defined here as ozone and its precursors, aerosols and black carbon) concentrations over Asia using satellite, ground-based and airborne observations. Key findings are that models reproduce homogeneously the trace gas observations although nitrous oxides are underestimated, whereas the aerosol distributions are heterogeneously reproduced implicating important uncertainties.
Atmos. Chem. Phys. Discuss., 15, 11049-11109, doi:10.5194/acpd-15-11049-2015, 2015
Monitoring compliance with sulphur content regulations of shipping fuel by in-situ measurements of ship emissions
Summary: On 1 January 2015, the International Maritime Organisation has tightened the regulations for sulfur content of shipping fuels in Sulfur Emission Control Areas. Here we present data from a station near Hamburg harbour in the North Sea SECA, which uses in-situ measurements of atmospheric trace gases to deduce the sulphur fuel content of passing ships. We compare data from 2014 before the regulation change and from January 2015 and show how this method can be used for compliance monitoring.
Atmos. Chem. Phys. Discuss., 15, 11031-11047, doi:10.5194/acpd-15-11031-2015, 2015
Characteristics and formation mechanism of continuous extreme hazes in China: a case study in autumn of 2014 in the North China Plain
Atmos. Chem. Phys. Discuss., 15, 10987-11029, doi:10.5194/acpd-15-10987-2015, 2015
On the scaling of the solar incident flux
Atmos. Chem. Phys. Discuss., 15, 10971-10986, doi:10.5194/acpd-15-10971-2015, 2015
What is the limit of stratospheric sulfur climate engineering?
Summary: The injection of sulfur dioxide is considered as an option for solar radiation management. We have calculated the effects of SO2 injections up to 100 Tg(S)/y. Our calculations show that the forcing efficieny of the injection decays exponentially. This result implies that SO2 injections in the order of 6 times Mt. Pinatubo eruptions per year are required to keep temperatures constant at that anticipated for 2020, whilst maintaining `business as usual' emission conditions.
Atmos. Chem. Phys. Discuss., 15, 10939-10969, doi:10.5194/acpd-15-10939-2015, 2015
Trace metal characterization of aerosol particles and cloud water during HCCT 2010
Atmos. Chem. Phys. Discuss., 15, 10899-10938, doi:10.5194/acpd-15-10899-2015, 2015
Biotic stress accelerates formation of climate-relevant aerosols in boreal forests
Summary: Global warming will induce large-scale insect outbreaks in boreal forests. Our results from field and laboratory experiments, satellite observations and global scale modelling suggest that more frequent insect outbreaks, in addition to temperature dependent increases in VOC emissions, could result in substantial increases in biogenic SOA formation and therefore affect both aerosol direct and indirect forcing of climate at regional scales. This should be considered in future climate predictions.
Atmos. Chem. Phys. Discuss., 15, 10853-10898, doi:10.5194/acpd-15-10853-2015, 2015
Sensitivity analysis of the potential impact of discrepancies in stratosphere–troposphere exchange on inferred sources and sinks of CO2
Summary: The upper troposphere and lower stratosphere (UTLS) is characterized by strong gradients in the distribution of long-lived tracers, which are sensitive to discrepancies in transport in models. We found that our model overestimates CO2 in the polar UTLS through comparison of modeled CO2 with aircraft observations. We then corrected the modeled CO2 and quantified the impact of the correction on the flux estimates using an atmospheric model together with atmospheric CO2 measured from a satellite.
Atmos. Chem. Phys. Discuss., 15, 10813-10851, doi:10.5194/acpd-15-10813-2015, 2015
Improvements in AOD retrieval from geostationary measurements over Asia with aerosol optical properties derived from the DRAGON-Asia campaign
Summary: Aerosol model optimized for East Asia is improved by applying inversion data from the DRAGON-Asia 2012 campaign, and is applied to an AOD retrieval algorithm using single visible measurement from GEO satellite. In sensitivity tests, a 4% overestimation in SSA can cause an underestimation over 20% in AOD. In accordance with the test, the overestimating tendency of AOD was improved by ~8% after the modification of the aerosol model.
Atmos. Chem. Phys. Discuss., 15, 10773-10812, doi:10.5194/acpd-15-10773-2015, 2015
Emissions of biogenic volatile organic compounds and subsequent formation of secondary organic aerosols in a Larix kaempferi forest
Summary: Simultaneous measurements of concentrations and above-canopy fluxes of isoprene and α-pinene in a forest, along with their oxidation products in aerosols, suggest that the inflow of anthropogenic precursors/aerosols enhanced the formation of both isoprene- and α-pinene-derived secondary organic aerosol (SOA) within the forest canopy even when the flux was low. We also emphasize the role of vegetation/soils near the forest floor as important sources of isoprene and α-pinene in the forest.
Atmos. Chem. Phys. Discuss., 15, 10739-10771, doi:10.5194/acpd-15-10739-2015, 2015
Parameterizations for convective transport in various cloud-topped boundary layers
Summary: By using Large-Eddy Simulation model data for 10 meteorological situations, we systematically studied the ability of current parameterizations, used in large-scale models, to capture convective transport by clouds. We found that the currently applied parameterization for the cloud area fraction does not suffice and a novel parameterization is proposed. Furthermore, the scaling of the upward velocity and the parameterization for the concentrations of atmospheric reactants are improved.
Atmos. Chem. Phys. Discuss., 15, 10709-10738, doi:10.5194/acpd-15-10709-2015, 2015
Particulate organic nitrates observed in an oil and natural gas production region during wintertime
Summary: Secondary organic aerosol affects both the environment and human health. We characterized the aerosol composition in Uintah Basin by measuring the concentration of nitrooxy group moiety which is produced through chemical interaction of volatile organic compounds and NOx emitted largely from local human activity. We found nitrooxy compounds to be a persistent, if not dominant, portion of fine aerosol mass. Similar results may be expected from emissions due to traffic in cities.
Atmos. Chem. Phys. Discuss., 15, 10677-10708, doi:10.5194/acpd-15-10677-2015, 2015
Variability of air ion concentrations in urban Paris
Atmos. Chem. Phys. Discuss., 15, 10629-10676, doi:10.5194/acpd-15-10629-2015, 2015
A PV-based determination of the transport barrier in the Asian summer monsoon anticyclone
Atmos. Chem. Phys. Discuss., 15, 10593-10628, doi:10.5194/acpd-15-10593-2015, 2015
Secondary organic aerosol formation from photochemical aging of light-duty gasoline vehicle exhausts in a smog chamber
Atmos. Chem. Phys. Discuss., 15, 10553-10592, doi:10.5194/acpd-15-10553-2015, 2015
Aerosol characterization over the southeastern United States using high resolution aerosol mass spectrometry: spatial and seasonal variation of aerosol composition, sources, and organic nitrates
Summary: Year-long comprehensive characterization of ambient aerosol was performed in both rural and urban sites in the southeastern US as part of Southeastern Center of Air Pollution and Epidemiology (SCAPE) study and Southeastern Oxidant and Aerosol Study (SOAS). Three independent methods were applied to estimate the concentration of particle-phase organic nitrates. The spatial distribution of organic aerosol is investigated by comparing simultaneous HR-ToF-AMS and ACSM measurements at different sites.
Atmos. Chem. Phys. Discuss., 15, 10479-10552, doi:10.5194/acpd-15-10479-2015, 2015
Current model capabilities for simulating black carbon and sulfate concentrations in the Arctic atmosphere: a multi-model evaluation using a comprehensive measurement data set
Summary: The concentrations of sulfate, black carbon and other aerosols in the Arctic are characterized by high values in late winter and spring (so-called Arctic Haze) and low values in summer. Models have long been struggling to capture this seasonality. In this study, we evaluate sulfate and BC concentrations from different updated models and emissions against a comprehensive pan-Arctic measurement data set. We find that the models improved, but still struggle to get the maximum concentrations.
Atmos. Chem. Phys. Discuss., 15, 10425-10477, doi:10.5194/acpd-15-10425-2015, 2015
Source attribution and process analysis for atmospheric mercury in East China simulated by CMAQ-Hg
Summary: This study estimated the contributions to mercury concentration and deposition in East China from seven categories of emission sources by CMAQ-Hg. Also, this study focuses on diagnostic and process analysis for atmospheric mercury pollution formation and identification of the dominant atmospheric processes for mercury.
Atmos. Chem. Phys. Discuss., 15, 10389-10424, doi:10.5194/acpd-15-10389-2015, 2015
Variability of aerosols forecast over the Mediterranean area during July 2013 (ADRIMED/CHARMEX)
Summary: The atmospheric composition was extensively studied in the Euro-Mediterranean region and during the summer 2013, in the framework of the ADRIMED project. During the campaign experiment, the WRF and CHIMERE models were used in forecast mode in order to help scientists to decide whether Intensive Observation Periods should be triggered or not. This study quantifies the origin of the forecast error by comparing several forecast leads to the corresponding measurements.
Atmos. Chem. Phys. Discuss., 15, 10341-10388, doi:10.5194/acpd-15-10341-2015, 2015
Effects of urban land expansion on the regional meteorology and air quality of Eastern China
Summary: In This paper, We examine the response of a range of meteorological and air quality indicators to the expansion of urban land using WRF/Chem. Our study indicates that 1) the responses of some meteorological factors and pollutant concentrations to the spatial extent of urbanization are linear near the surface, but nonlinear at higher altitudes; 2) urban heat island circulation and a deeper boundary layer with stronger turbulent intensities play significant roles in relocating the pollutants.
Atmos. Chem. Phys. Discuss., 15, 10299-10340, doi:10.5194/acpd-15-10299-2015, 2015
A mechanism for biologically-induced iodine emissions from sea-ice
Atmos. Chem. Phys. Discuss., 15, 10257-10297, doi:10.5194/acpd-15-10257-2015, 2015
Uncertainties in global aerosols and climate effects due to biofuel emissions
Summary: We examine sensitivities in aerosol concentration and climate effects from biofuel combustion emissions. We find a strong sensitivity in the overall sign and magnitude of the direct radiative effect and cloud-albedo indirect effect due to uncertainties regarding emissions size distribution, composition, mass, and optical mixing-state. This uncertainty limits our ability to evaluate black carbon mitigation strategies to counter warming effects from greenhouse-gases.
Atmos. Chem. Phys. Discuss., 15, 10199-10256, doi:10.5194/acpd-15-10199-2015, 2015
Detection of anthropogenic dust using CALIPSO lidar measurements
Atmos. Chem. Phys. Discuss., 15, 10163-10198, doi:10.5194/acpd-15-10163-2015, 2015
Receptor modelling of both particle composition and size distribution from a background site in London, UK
Summary: Particles in the air of London have been assessed both by weight and by number. They have also been subject to chemical analysis. The data from two years of sampling have been used to investigate the sources contributing to the measured concentrations both in terms of the weight of the particles and the number of particles.
Atmos. Chem. Phys. Discuss., 15, 10123-10162, doi:10.5194/acpd-15-10123-2015, 2015
A method for merging nadir-sounding climate records, with an application to the global-mean stratospheric temperature data sets from SSU and AMSU
Summary: This is the first paper of its kind describing a method for merging the long-term satellite records of global stratospheric temperature from SSU and AMSU to yield a continuous data set from 1979 to present (and beyond). Since global-mean stratospheric temperature is close to radiative equilibrium, our "extended" SSU data set is an important climate record for the detection and attribution of anthropogenic influence.
Atmos. Chem. Phys. Discuss., 15, 10085-10122, doi:10.5194/acpd-15-10085-2015, 2015
A Match-based approach to the estimation of polar stratospheric ozone loss using Aura Microwave Limb Sounder observations
Summary: Employing the well-established "Match" technique, we quantify polar stratospheric ozone loss during multiple Arctic and Antarctic winters, based on observations from the spaceborne Aura Microwave Limb Sounder (MLS) instrument. The dense MLS spatial coverage enables many more matches than is possible for balloon-based observations. Applying the same technique to MLS observations of the long-lived N2O molecule gives an measure of the impact of transport errors on our ozone loss estimates.
Atmos. Chem. Phys. Discuss., 15, 10041-10083, doi:10.5194/acpd-15-10041-2015, 2015
The influences of mass loading and rapid dilution of secondary organic aerosol on particle volatility
Summary: Secondary organic aerosol from the dark ozonolysis of α‑pinene was formed at a range of mass loadings from 1-800μg m-3. The amount of mass loss during evaporation in a thermodenuder was found to be independent of mass loading. A kinetic model of evaporation was fit to the observations and good agreement was obtained when the particle was either composed of dimers that decompose into semi-volatile monomers or when it was composed of low-volatility compounds that evaporate directly.
Atmos. Chem. Phys. Discuss., 15, 9997-10039, doi:10.5194/acpd-15-9997-2015, 2015
Impact of different Asian source regions on the composition of the Asian monsoon anticyclone and on the extratropical lowermost stratosphere
Summary: The Asian summer monsoon circulation is an important global circulation system associated with strong upward transport of tropospheric source gases. We show that the contribution of different boundary source regions to the Asian monsoon anticyclone strongly depends on its intraseasonal variability and that emissions from Asia have a significant impact on the chemical compositions of the lowermost stratosphere of the northern hemisphere at the end of the monsoon season in Sep./Oct. 2012.
Atmos. Chem. Phys. Discuss., 15, 9941-9995, doi:10.5194/acpd-15-9941-2015, 2015
Particle sized-resolved source apportionment of primary and secondary organic tracer compounds at urban and rural locations in Spain
Summary: Molecular organic tracer compounds were analyzed in six particle sizes in an urban background site (Barcelona) and in a rural site in Spain. The results improve considerably our current understanding on the composition and particle-size distribution of organic air pollution in traffic intensive urban areas and rural sites where combustion of biomass plays an important role on the local and regional air quality, either by emissions from open fires or from domestic heating.
Atmos. Chem. Phys. Discuss., 15, 9897-9939, doi:10.5194/acpd-15-9897-2015, 2015
Development and optimization of a wildfire plume rise model based on remote sensing data inputs – Part 2
Summary: The transport of Biomass Burning emissions in Chemical Transport Model rely on parametrization of plumes injection height. Using fire observation selected to ensure match-up of fire-atmosphere-plume dynamics; a popular plume rise model was improved and optimized. The resulting model shows response to the effect of atmospheric stability consistent with previous findings and is able to predict higher injection height than any other tested parametrizations, giving a closer match with observation.
Atmos. Chem. Phys. Discuss., 15, 9815-9895, doi:10.5194/acpd-15-9815-2015, 2015
A review of approaches to estimate wildfire plume injection height within large scale atmospheric chemical transport models – Part 1
Summary: Landscape fire plume height controls fire emissions release in the atmosphere, in particular their transport that may also affect the longevity, chemical conversion and fate of the plumes chemical constituents. Here, we review how such landscape-scale fire smoke plume injection heights are represented in large scale atmospheric transport models aiming to represent the impacts of wildfire emissions on component of the Earth system.
Atmos. Chem. Phys. Discuss., 15, 9767-9813, doi:10.5194/acpd-15-9767-2015, 2015
The MCM v3.3 degradation scheme for isoprene
Summary: Atmospheric isoprene oxidation has an important effect on the formation of pollutants such as ozone and particles. A reliable representation is an essential component of climate change/air quality models. Systematic updates to the detailed chemistry in the MCM are described, with reference to recently reported kinetic/mechanistic data. Results of box model calculations are used to illustrate the impacts of the updates, with particular focus on the key atmospheric cycles involving HOx and NOx.
Atmos. Chem. Phys. Discuss., 15, 9709-9766, doi:10.5194/acpd-15-9709-2015, 2015
New fire diurnal cycle characterizations to improve fire radiative energy assessments made from low-Earth orbit satellites sampling
Summary: The polar orbiting MODIS instruments provide around four daily observations of the fire diurnal cycle. When using MODIS observations, ignoring the fire diurnal cycle caused structural errors in the estimations of fire radiated energy. The fire diurnal cycle varied as a function of climate and vegetation type, while fire size was a good indicator for the spatial distribution. Including information on the climatology of the fire diurnal cycle significantly improved the model performance.
Atmos. Chem. Phys. Discuss., 15, 9661-9707, doi:10.5194/acpd-15-9661-2015, 2015
Meteor radar quasi two-day wave observations over 10 years at Collm (51.3° N, 13.0° E)
Atmos. Chem. Phys. Discuss., 15, 9631-9659, doi:10.5194/acpd-15-9631-2015, 2015
Black-carbon-surface oxidation and organic composition of beech-wood soot aerosols
Summary: The chemical composition of wood-combustion soot is investigated using a Soot-Particle Aerosol Mass Spectrometer. The analysis elucidates real-time information on BC oxygenated surface functional groups for a real-world source for the first time. Positive Matrix Factorization, using a new AMS error model, provides additional insights into the source of organic material in this soot.
Atmos. Chem. Phys. Discuss., 15, 9573-9629, doi:10.5194/acpd-15-9573-2015, 2015
Diesel-related hydrocarbons can dominate gas phase reactive carbon in megacities
Summary: Technological shifts between fuel sources have had unexpected impacts on atmospheric composition and these significant changes can go undetected if source-specific monitoring infrastructure is not in place. We present chemically comprehensive, continuous measurements of organic compounds in a developed megacity (London), that show diesel-related hydrocarbons can dominate reactive carbon and ozone formation potential, highlighting a serious underestimation of this source in emission inventories.
Atmos. Chem. Phys. Discuss., 15, 9541-9571, doi:10.5194/acpd-15-9541-2015, 2015
Aerosol vertical distribution, optical properties and transport over Corsica (western Mediterranean)
Summary: This paper presents the aerosol vertical distribution observed by lidar soundings in Corsica (western Mediterranean) between February 2012 and August 2013. A seasonal cycle is observed in the extinction coefficient profiles and aerosol optical thickness with minima in winter and maxima in spring-summer. Less than 10% of the daily observations show high AOD corresponding to the large-scale advection of desert dust from Northern Africa or pollution aerosols from Europe.
Atmos. Chem. Phys. Discuss., 15, 9507-9540, doi:10.5194/acpd-15-9507-2015, 2015
Vertical profiling of aerosol hygroscopic properties in the planetary boundary layer during the PEGASOS campaigns
Summary: This study presents PEGASOS project data from field campaigns in the Po Valley, Italy and the Netherlands. Vertical profiles of aerosol hygroscopicity and chemical composition were investigated with airborne measurements on board a Zeppelin NT airship. A special focus was on the evolution of different mixing layers within the PBL as a function of daytime. A closure study showed that variations in aerosol hygroscopicity can well be explained by the variations in chemical composition.
Atmos. Chem. Phys. Discuss., 15, 9445-9505, doi:10.5194/acpd-15-9445-2015, 2015
Size-resolved source apportionment of particulate matter in urban Beijing during haze and non-haze episodes
Summary: Size-resolved chemical information of particulate matter remains unclear in China due to a paucity of measurement data. One-year observation of water-soluble ions, carbonaceous species and trace elements in size-resolved particles with cutoff points as 0.43, 0.65, 1.1, 2.1, 3.3, 4.7, 5.8 and 9.0μm were conducted in mega city Beijing. This unique dataset provided multidimensional insights into the sources among different size fractions, seasons or wind flows and between non-haze and haze days.
Atmos. Chem. Phys. Discuss., 15, 9405-9443, doi:10.5194/acpd-15-9405-2015, 2015
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Ice nucleation terminology
Atmos. Chem. Phys. Discuss., 14, 22155-22162, doi:10.5194/acpd-14-22155-2014, 2014