Influence of the aerosol solar extinction on photochemistry during the 2010 Russian wildfires episode
Atmos. Chem. Phys., 15, 10983-10998, doi:10.5194/acp-15-10983-2015, 2015
Ozone and NOx chemistry in the eastern US: evaluation of CMAQ/CB05 with satellite (OMI) data
Atmos. Chem. Phys., 15, 10965-10982, doi:10.5194/acp-15-10965-2015, 2015
A study of the impact of synoptic weather conditions and water vapor on aerosol–cloud relationships over major urban clusters of China
Summary: The impact of aerosols on cloud cover (CC) under the influence of water vapor is studied using a decade of satellite observations. Water vapor is found to have a stronger impact on CC than aerosols. The water vapor impact shows that the hydrological cycle interferes with the aerosol climatic impact, and we need to improve our understanding of this interference.
Atmos. Chem. Phys., 15, 10955-10964, doi:10.5194/acp-15-10955-2015, 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., 15, 10939-10953, doi:10.5194/acp-15-10939-2015, 2015
Influence of synoptic patterns on surface ozone variability over the eastern United States from 1980 to 2012
Summary: In this study, we have examined the effect of polar jet and Bermuda High on ozone air quality in the eastern United States. In the Midwest and northeast, the poleward shift of jet wind leads to reduced polar jet frequency, resulting in increased ozone there. In the southeast, the influence of Bermuda High on ozone variability depends on the location of its west edge. Westward movement increases the ozone only when the JJA Bermuda High west edge is located west of 85.4°W.
Atmos. Chem. Phys., 15, 10925-10938, doi:10.5194/acp-15-10925-2015, 2015
Atmospheric nitrogen deposition to the northwestern Pacific: seasonal variation and source attribution
Summary: Rapid Asian industrialization has led to increased atmospheric nitrogen deposition downwind. This work analyzes the sources and processes controlling atmospheric nitrogen deposition to the northwestern Pacific. Both nitrogen emissions and meteorology, largely controlled by the East Asian Monsoon, determine the seasonality of nitrogen deposition. Ascribing deposition over the marginal seas to nitrogen sources from different regions and sectors shows important contribution from fertilizer use.
Atmos. Chem. Phys., 15, 10905-10924, doi:10.5194/acp-15-10905-2015, 2015
Simulation of black carbon in snow and its climate impact in the Canadian Global Climate Model
Summary: A new parameterization of black carbon in snow in the Canadian Atmospheric Global Climate Model provides realistic simulations of radiative forcings. BC emissions and simulated BC concentrations in snow have changed substantially in recent decades. However, simulated impacts of changes in BC concentrations in snow from 1950-1959 to 2000-2009 on snow reflectivity and snow extent in the Northern Hemisphere are very small, with few regional exceptions, in contrast to results from earlier studies.
Atmos. Chem. Phys., 15, 10887-10904, doi:10.5194/acp-15-10887-2015, 2015
Spatiotemporal variations of air pollutants (O3, NO2, SO2, CO, PM10, and VOCs) with land-use types
Summary: Major air pollutants (O3, NO2, SO2, CO, PM10, and VOCs) with long-term records from a dense observation network over Korea were extensively analyzed with land-use types, classified by Korean government, consistent with satellite-observed land covers. The weekly cycles of the pollutant showed different behaviors with the types. Regardless of land-use types, ozone has an increasing trend, while the other pollutants have decreasing trends. Most areas in Korea were VOCs-limited for ozone chemistry.
Atmos. Chem. Phys., 15, 10857-10885, doi:10.5194/acp-15-10857-2015, 2015
Springtime daily variations in lower-tropospheric ozone over east Asia: the role of cyclonic activity and pollution as observed from space with IASI
Summary: We identify the stratospheric and the photochemical sources contributing to the late-spring O3 distribution over East Asia using IASI O3 and CO observations. Reversible subsiding O3 transfers in the UTLS associated with low-pressure systems impact lower-tropospheric O3 north of 40°N. By contrast, photochemical production from primary pollutants significantly contributes to the enhanced lower-tropospheric O3 over the NCP and photochemical processing occurs within the plume exported from the NCP.
Atmos. Chem. Phys., 15, 10839-10856, doi:10.5194/acp-15-10839-2015, 2015
Stable carbon isotope ratios of ambient secondary organic aerosols in Toronto
Atmos. Chem. Phys., 15, 10825-10838, doi:10.5194/acp-15-10825-2015, 2015
Chemical characterization of submicron aerosol and particle growth events at a national background site (3295 m a.s.l.) on the Tibetan Plateau
Summary: A fall field campaign was conducted at a national background site (3295m a.s.l.) over the Tibetan Plateau. The submicron aerosol was dominated by organics (43%) and sulfate (28%). Secondary organic aerosol (SOA) dominated OA (85%), 17% of which being aged biomass burning OA. New particle formation and growth events were frequently observed, with an average particle growth rate of 2.0nm per hour. The important role of organics in particle growth in the Tibetan Plateau was also demonstrated.
Atmos. Chem. Phys., 15, 10811-10824, doi:10.5194/acp-15-10811-2015, 2015
The NOx dependence of bromine chemistry in the Arctic atmospheric boundary layer
Atmos. Chem. Phys., 15, 10799-10809, doi:10.5194/acp-15-10799-2015, 2015
Modelling the contribution of biogenic volatile organic compounds to new particle formation in the Jülich plant atmosphere chamber
Summary: We used the ADCHAM model to study new particle formation events in the JPAC chamber. The model results show that the new particles may be formed by a kinetic type of nucleation involving both sulphuric acid and organic compounds formed from OH oxidation of volatile organic compounds (VOCs). The observed particle growth may either be controlled by the condensation of semi- and low-volatililty organic compounds or by the formation of low-volatility compounds (oligomers) at the particle surface.
Atmos. Chem. Phys., 15, 10777-10798, doi:10.5194/acp-15-10777-2015, 2015
The Amazon Tall Tower Observatory (ATTO): overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols
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 3 years of operation.
Atmos. Chem. Phys., 15, 10723-10776, doi:10.5194/acp-15-10723-2015, 2015
Thermodynamics of the formation of sulfuric acid dimers in the binary (H2SO4–H2O) and ternary (H2SO4–H2O–NH3) system
Summary: New particle formation (NPF) is an important atmospheric process. At cold temperatures in the upper troposphere the binary (H2SO4-H2O) and ternary (H2SO4-H2O-NH3) system are thought to be important for NPF. Sulfuric acid monomer (H2SO4) and sulfuric acid dimer ((H2SO4)2) concentrations were measured between 208 and 248K for these systems and dimer evaporation rates were derived. These data will help to better understand and predict binary and ternary nucleation at low temperatures.
Atmos. Chem. Phys., 15, 10701-10721, doi:10.5194/acp-15-10701-2015, 2015
Strong aerosol–cloud interaction in altocumulus during updraft periods: lidar observations over central Europe
Atmos. Chem. Phys., 15, 10687-10700, doi:10.5194/acp-15-10687-2015, 2015
Influence of crustal dust and sea spray supermicron particle concentrations and acidity on inorganic NO3− aerosol during the 2013 Southern Oxidant and Aerosol Study
Summary: We report ion chromatographic measurements of gas- and aerosol-phase inorganic species at the SOAS 2013 field study. Our particular focus is on inorganic nitrate aerosol formation via HNO3 uptake onto coarse-mode dust and sea salt particles, which we find to be the dominant source of episodic inorganic nitrate at this site, due to the high acidity of the particles preventing formation of NH4NO3. We calculate a production rate of inorganic nitrate aerosol.
Atmos. Chem. Phys., 15, 10669-10685, doi:10.5194/acp-15-10669-2015, 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 characteristics 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 and 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., 15, 10645-10667, doi:10.5194/acp-15-10645-2015, 2015
The role of ice nuclei recycling in the maintenance of cloud ice in Arctic mixed-phase stratocumulus
Summary: The maintenance of cloud ice production in Arctic mixed-phase stratocumulus is investigated in large eddy simulations that include a prognostic ice nuclei (IN) formulation and a diurnal cycle. It is demonstrated that IN recycling through subcloud sublimation prolongs ice production. Competing feedbacks between dynamical mixing and recycling are found to slow the rate of ice lost. The results of this study have important implications for the maintenance of phase partitioning in Arctic clouds.
Atmos. Chem. Phys., 15, 10631-10643, doi:10.5194/acp-15-10631-2015, 2015
Motion-correlated flow distortion and wave-induced biases in air–sea flux measurements from ships
Summary: Signals at scales associated with wave and platform motion are often apparent in ship-based turbulent flux measurements, but it has been uncertain whether this is due to measurement error or to wind-wave interactions. We show that the signal has a dependence on horizontal ship velocity and that removing the signal reduces the dependence of the momentum flux on the orientation of the ship to the wind. We conclude that the signal is a bias due to time-varying motion-dependent flow distortion.
Atmos. Chem. Phys., 15, 10619-10629, doi:10.5194/acp-15-10619-2015, 2015
A global aerosol classification algorithm incorporating multiple satellite data sets of aerosol and trace gas abundances
Atmos. Chem. Phys., 15, 10597-10618, doi:10.5194/acp-15-10597-2015, 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 4217 stations in North 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., 15, 10581-10596, doi:10.5194/acp-15-10581-2015, 2015
NO2 seasonal evolution in the north subtropical free troposphere
Summary: The NO2 seasonal evolution in the free troposphere (FT) has been established for the first time, based on a remote sensing technique (MAXDOAS) and thus avoiding the problems of the local pollution of in situ instruments. A clear seasonality has been found, with background levels of 20-40pptv. Evidence has been found on fast, direct injection of surface air into the free troposphere. This result might have implications on the FT distribution of halogens and other species with marine sources.
Atmos. Chem. Phys., 15, 10567-10579, doi:10.5194/acp-15-10567-2015, 2015
Evaluating the climate and air quality impacts of short-lived pollutants
Summary: This paper presents a summary of the findings of the ECLIPSE EU project. The project has investigated the climate and air quality impacts of short-lived climate pollutants (especially methane, ozone, aerosols) and has designed a global mitigation strategy that maximizes co-benefits between air quality and climate policy. Transient climate model simulations allowed quantifying the impacts on temperature (e.g., reduction in global warming by 0.22K for the decade 2041-2050) and precipitation.
Atmos. Chem. Phys., 15, 10529-10566, doi:10.5194/acp-15-10529-2015, 2015
Acetylene (C2H2) and hydrogen cyanide (HCN) from IASI satellite observations: global distributions, validation, and comparison with model
Summary: We present global distributions of acetylene (C2H2) and hydrogen cyanide (HCN) total columns derived from the Infrared Atmospheric Sounding Interferometer (IASI). C2H2 and HCN are ubiquitous atmospheric trace gases with medium tropospheric lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. We show that there is an overall agreement between ground-based and space measurements, as well as model simulations.
Atmos. Chem. Phys., 15, 10509-10527, doi:10.5194/acp-15-10509-2015, 2015
Global OZone Chemistry And Related trace gas Data records for the Stratosphere (GOZCARDS): methodology and sample results with a focus on HCl, H2O, and O3
Atmos. Chem. Phys., 15, 10471-10507, doi:10.5194/acp-15-10471-2015, 2015
Ice phase in altocumulus clouds over Leipzig: remote sensing observations and detailed modeling
Summary: The paper combines remote sensing observations and detailed cloud modeling. It was shown that the main features of the observations could be captured which allows one to perform sensitivity studies. Those show that the liquid phase is mainly determined by the dynamical parameters of the model, whereas the ice phase is dominated by microphysical parameters such as ice nuclei number and ice particle shape.
Atmos. Chem. Phys., 15, 10453-10470, doi:10.5194/acp-15-10453-2015, 2015
Model studies of volatile diesel exhaust particle formation: are organic vapours involved in nucleation and growth?
Atmos. Chem. Phys., 15, 10435-10452, doi:10.5194/acp-15-10435-2015, 2015
Sources, seasonality, and trends of southeast US aerosol: an integrated analysis of surface, aircraft, and satellite observations with the GEOS-Chem chemical transport model
Atmos. Chem. Phys., 15, 10411-10433, doi:10.5194/acp-15-10411-2015, 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 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., 15, 10399-10410, doi:10.5194/acp-15-10399-2015, 2015
Variability in Antarctic ozone loss in the last decade (2004–2013): high-resolution simulations compared to Aura MLS observations
Summary: Our study finds large interannual variability in Antarctic ozone loss in the recent decade, with a number of winters showing shallow ozone holes but also with the year of the largest ozone hole in the last decades. These smaller ozone holes or ozone losses are mainly related to the year-to-year changes in dynamical processes rather than the variations in anthropogenic ozone-depleting substances (ODSs), as the change in ODS levels during the study period was very small.
Atmos. Chem. Phys., 15, 10385-10397, doi:10.5194/acp-15-10385-2015, 2015
Emissions of nitrogen oxides from US urban areas: estimation from Ozone Monitoring Instrument retrievals for 2005–2014
Summary: Using an exponentially modified Gaussian method and taking into account the effect of wind on NO2 distributions, we estimate 3-year moving-average emissions of summertime NOx from 35 US urban areas directly from NO2 retrievals of the OMI during 2005−2014. Total OMI-derived NOx emissions over US urban areas decreased by 49%, consistent with reductions of 43, 49, and 44% in the bottom-up NOx emissions, the weak-wind OMI NO2 burdens, and the averaged NO2 concentrations, respectively.
Atmos. Chem. Phys., 15, 10367-10383, doi:10.5194/acp-15-10367-2015, 2015
Investigating the observed sensitivities of air-quality extremes to meteorological drivers via quantile regression
Atmos. Chem. Phys., 15, 10349-10366, doi:10.5194/acp-15-10349-2015, 2015
Comprehensive mapping and characteristic regimes of aerosol effects on the formation and evolution of pyro-convective clouds
Atmos. Chem. Phys., 15, 10325-10348, doi:10.5194/acp-15-10325-2015, 2015
Sensitivity estimations for cloud droplet formation in the vicinity of the high-alpine research station Jungfraujoch (3580 m a.s.l.)
Summary: An important quantity which determines aerosol activation and cloud formation is the effective peak supersaturation. The box model ZOMM was used to simulate the effective peak supersaturation experienced by an air parcel approaching a high-alpine research station in Switzerland. With the box model the sensitivity of the effective peak supersaturation to key aerosol and dynamical parameters was investigated.
Atmos. Chem. Phys., 15, 10309-10323, doi:10.5194/acp-15-10309-2015, 2015
Constraining black carbon aerosol over Asia using OMI aerosol absorption optical depth and the adjoint of GEOS-Chem
Summary: We attempt to reduce uncertainties in BC emissions and improve BC model simulations by developing top-down, spatially resolved, estimates of BC emissions through assimilation of OMI observations of aerosol absorption optical depth (AAOD) with the GEOS-Chem model and its adjoint for April and October of 2006. Despite the limitations and uncertainties, using OMI AAOD to constrain BC sources we are able to improve model representation of BC distributions, particularly over China.
Atmos. Chem. Phys., 15, 10281-10308, doi:10.5194/acp-15-10281-2015, 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., 15, 10271-10280, doi:10.5194/acp-15-10271-2015, 2015
Technical Note: A proposal for ice nucleation terminology
Summary: Clarification is needed in the terminology used to discuss ice nucleation in the literature. Conflicting interpretations coupled with uncertainties about the details of the processes have led to difficulties in the clear communication of results and ideas. This paper contains a proposal for future usage. This proposed terminology was arrived at as a result of a year-long exchange of suggestions by a number of scientists.
Atmos. Chem. Phys., 15, 10263-10270, doi:10.5194/acp-15-10263-2015, 2015
Simultaneous monitoring of stable oxygen isotope composition in water vapour and precipitation over the central Tibetan Plateau
Atmos. Chem. Phys., 15, 10251-10262, doi:10.5194/acp-15-10251-2015, 2015
Effect of tropical cyclones on the tropical tropopause parameters observed using COSMIC GPS RO data
Summary: The effect of tropical cyclones (TCs) that occurred over the north Indian Ocean in the last decade on the tropical tropopause parameters has been quantified for the first time. The vertical structure of temperature and tropopause parameters within the 5º radius away from the cyclone centre during TC period is also presented. The water vapour variability in the vicinity of TC is investigated. It is demonstrated that the TCs can significantly affect the tropical tropopause and thus STE processes.
Atmos. Chem. Phys., 15, 10239-10249, doi:10.5194/acp-15-10239-2015, 2015
In situ formation and spatial variability of particle number concentration in a European megacity
Summary: Aerosol size distribution measurements from three ground sites, two mobile laboratories, and one airplane are combined to investigate the spatial and temporal variability of ultrafine particles in and around Paris during the summer and winter MEGAPOLI campaigns. The role of nucleation as a particle source and the influence of Paris emissions on their surroundings are examined.
Atmos. Chem. Phys., 15, 10219-10237, doi:10.5194/acp-15-10219-2015, 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 occurs over large areas above the sea, but the process is clearly promoted at high altitude, above 1000m, i.e. frequently in the free troposphere. NPF also seems to be mainly influenced by local processes occurring above the sea. After their formation, particles slowly grow at high altitude while not being greatly depleted or affected by coagulation.
Atmos. Chem. Phys., 15, 10203-10218, doi:10.5194/acp-15-10203-2015, 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., 15, 10183-10201, doi:10.5194/acp-15-10183-2015, 2015
Deuterium excess in the atmospheric water vapour of a Mediterranean coastal wetland: regional vs. local signatures
Summary: Based on summer measurements of δ18O and δD in the atmospheric vapour of a Mediterranean coastal wetland exposed to high evaporation, this paper explores the main drivers of isotopic signal variability. After having classified the data according to the main regional air mass trajectories, average diurnal cycles are discussed with regards to the contribution of local evaporation to the ground level atmospheric vapour.
Atmos. Chem. Phys., 15, 10167-10181, doi:10.5194/acp-15-10167-2015, 2015
Long-term real-time measurements of aerosol particle composition in Beijing, China: seasonal variations, meteorological effects, and source analysis
Summary: We conducted the first long-term real-time measurement of submicron aerosol composition in Beijing using an ACSM for 1 year. The seasonal variations of mass concentrations and chemical composition of submicron aerosol were investigated in detail, and the meteorological effects on aerosol chemistry, particularly temperature and relative humidity, were elucidated. Finally, the potential source areas of aerosol species during four seasons were identified.
Atmos. Chem. Phys., 15, 10149-10165, doi:10.5194/acp-15-10149-2015, 2015
Quantitative assessment of atmospheric emissions of toxic heavy metals from anthropogenic sources in China: historical trend, spatial 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 account of economic transitions and pollution control technology improvement. 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., 15, 10127-10147, doi:10.5194/acp-15-10127-2015, 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 2 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., 15, 10107-10125, doi:10.5194/acp-15-10107-2015, 2015
Impact of climate and land cover changes on tropospheric ozone air quality and public health in East Asia between 1980 and 2010
Summary: Historical land cover and land use change alone between 1980 and 2010 could lead to reduced summertime surface ozone by up to 4ppbv in East Asia. Climate change alone could lead to an increase in summertime ozone by 2-10ppbv in most of East Asia. Land cover change could offset part of the climate effect and lead to a previously unknown public health benefit. The sensitivity of surface ozone to land cover change is more dependent on dry deposition than isoprene emission in most of East Asia.
Atmos. Chem. Phys., 15, 10093-10106, doi:10.5194/acp-15-10093-2015, 2015
Monitoring compliance with sulfur content regulations of shipping fuel by in situ measurements of ship emissions
Summary: On 1 January 2015, the International Maritime Organisation 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., 15, 10087-10092, doi:10.5194/acp-15-10087-2015, 2015
Turbulence vertical structure of the boundary layer during the afternoon transition
Summary: A case study of the BLLAST experiment is considered to explore the decay of turbulence that occurs in the convective boundary layer over land during the afternoon. Based on observations and on a large-eddy simulation, the analysis reveals two phases in the afternoon: a first quasi-stationary phase when the turbulent kinetic energy slowly decays without significant change in the turbulence structure and a second phase of more rapid decay with a change in spectral turbulence characteristics.
Atmos. Chem. Phys., 15, 10071-10086, doi:10.5194/acp-15-10071-2015, 2015
Black carbon concentrations and mixing state in the Finnish Arctic
Summary: We have measured atmospheric aerosol composition by using a Single Particle Soot Photometer (SP2) in the Finnish Arctic during winter 2011-2012. SP2 can give detailed information about mass distributions and mixing state of refractory black carbon (rBC). The measurements showed varying rBC mass concentrations, but relatively constant rBC core size distributions and mixing state parameters. On average, 24% of all particles contain rBC and the observed rBC cores are always thickly coated.
Atmos. Chem. Phys., 15, 10057-10070, doi:10.5194/acp-15-10057-2015, 2015
Impact of 2050 climate change on North American wildfire: consequences for ozone air quality
Summary: Based on simulated meteorology from 13 GCMs, we projected future wildfire activity in Alaskan and Canadian ecoregions by the mid-century. The most robust change is the increase of 150-390% in area burned over Alaska and western Canada. The models also predict an increase of 45-90% in the central and southern Canadian ecoregions, but a decrease of up to 50% in northern Canada. We further quantify how the changes in wildfire emissions may affect ozone concentrations in North America.
Atmos. Chem. Phys., 15, 10033-10055, doi:10.5194/acp-15-10033-2015, 2015
Ensemble data assimilation of total column ozone using a coupled meteorology–chemistry model and its impact on the structure of Typhoon Nabi (2005)
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 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., 15, 10019-10031, doi:10.5194/acp-15-10019-2015, 2015
Can a coupled meteorology–chemistry model reproduce the historical trend in aerosol direct radiative effects over the Northern Hemisphere?
Summary: The ability of a coupled meteorology-chemistry model (WRF-CMAQ) to reproduce the historical trend in AOD and clear-sky SWR over the N. Hemisphere has been evaluated through a comparison of 21-year simulated results with observation-derived records from 1990 to 2010. Questions of how well the model represents the regional and temporal variability of aerosol burden and DRE, and whether the model is able to capture past trends in aerosol loading and associated radiation effects, will be addressed.
Atmos. Chem. Phys., 15, 9997-10018, doi:10.5194/acp-15-9997-2015, 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., 15, 9983-9996, doi:10.5194/acp-15-9983-2015, 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 data sets. 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. Furthermore, the downward trend in upper stratospheric ozone has not continued. The possible significance of any increase is discussed in detail.
Atmos. Chem. Phys., 15, 9965-9982, doi:10.5194/acp-15-9965-2015, 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., 15, 9945-9963, doi:10.5194/acp-15-9945-2015, 2015
Ergodicity test of the eddy-covariance technique
Summary: The ergodic theorem of stationary random processes is introduced to analyse and verify the ergodicity of atmospheric turbulence measured using the eddy-covariance technique with two sets of field observational data. The results show that the ergodicity of atmospheric turbulence in atmospheric boundary layer is relative not only to the atmospheric stratification but also to the eddy scale of atmospheric turbulence.
Atmos. Chem. Phys., 15, 9929-9944, doi:10.5194/acp-15-9929-2015, 2015
Meteor radar quasi 2-day wave observations over 10 years at Collm (51.3° N, 13.0° E)
Summary: The quasi 2-day wave (QTDW), one of the most striking features in the mesosphere/lower thermosphere, is analyzed using meteor radar measurements at Collm (51°N, 13°E) during 2004-2014. The QTDW has periods lasting between 43 and 52h during strong summer bursts, and weaker enhancements are found during winter. A correlation between QTDW amplitudes and wind shear suggests baroclinic instability to be a likely forcing mechanism.
Atmos. Chem. Phys., 15, 9917-9927, doi:10.5194/acp-15-9917-2015, 2015
Consistent response of Indian summer monsoon to Middle East dust in observations and simulations
Summary: Satellite data show that Indian summer monsoon (ISM) rainfall is closely associated with Middle East dust aerosols. Numerical modeling shows that the increased ISM rainfall is related to the enhanced southwesterly flow and moisture transport from the Arabian Sea to the Indian subcontinent, associated with the development of an anomalous low-pressure system over the Iranian Plateau and the Arabian Sea due to dust-induced atmospheric heating.
Atmos. Chem. Phys., 15, 9897-9915, doi:10.5194/acp-15-9897-2015, 2015
Atmospheric chemistry of nitrogenous aerosols in northeastern Asia: biological sources and secondary formation
Atmos. Chem. Phys., 15, 9883-9896, doi:10.5194/acp-15-9883-2015, 2015
Observation of ozone enhancement in the lower troposphere over East Asia from a space-borne ultraviolet spectrometer
Summary: The lower tropospheric ozone distribution maps were first obtained from the recent retrieval products of the Ozone Monitoring Instrument (OMI) onboard the Earth Observing System (EOS) Aura satellite. We found significant enhancement of ozone in the lower troposphere over central and eastern China (CEC), with Shandong Province as its center, and most notable in June in any given year. Similar seasonal variations were observed throughout the 9-year OMI measurement period of 2005 to 2013.
Atmos. Chem. Phys., 15, 9865-9881, doi:10.5194/acp-15-9865-2015, 2015
Is there 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 shows 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., 15, 9851-9863, doi:10.5194/acp-15-9851-2015, 2015