Size-resolved measurements of ice nucleating particles at six locations in North America and one in Europe
Atmos. Chem. Phys. Discuss., 15, 20521-20559, doi:10.5194/acpd-15-20521-2015, 2015
The impact of residential combustion emissions on atmospheric aerosol, human health and climate
Summary: We estimate the impact of residential emissions (cooking and heating) on atmospheric aerosol, human health and climate. We find large contributions to annual mean ambient PM2.5 in residential sources regions resulting in significant but uncertain global premature mortality when key uncertainties in emission flux are considered. We show that residential emissions exert an uncertain global radiative effect, and suggest more work is needed to characterise residential emissions climate importance.
Atmos. Chem. Phys. Discuss., 15, 20449-20520, doi:10.5194/acpd-15-20449-2015, 2015
The imprint of stratospheric transport on column-averaged methane
Summary: We find that stratospheric model-transport errors are common for chemical transport models that are used for inverse estimates of CH4 emissions. These model-transport errors cause latitudinal as well as seasonal biases in simulated stratospheric and, hence, column-averaged CH4 mixing ratios (XCH4). Such a model bias corresponds to an overestimation of arctic and mid-latitude CH4 emissions if inversion studies do not apply an ad hoc bias correction before inverting fluxes from XCH4 observations.
Atmos. Chem. Phys. Discuss., 15, 20395-20447, doi:10.5194/acpd-15-20395-2015, 2015
Effects of dust particle internal structure on light scattering
Summary: Internal structures are a common in atmospheric dust particles, yet their effects on light scattering are largely unstudied. In this work, we study how hematite nodes, internal voids and hematite-rich coating impact single-scattering properties of computationally generated irregular model particles. The results show that all of these features change scattering properties significantly, and that a simple effective-medium approximation is not enough to replicate the scattering properties.
Atmos. Chem. Phys. Discuss., 15, 20349-20394, doi:10.5194/acpd-15-20349-2015, 2015
Implications of model bias in carbon monoxide for methane lifetime
Summary: A low bias in carbon monoxide (CO) at northern latitudes is a common feature of chemistry climate models. We find that increasing northern hemisphere (NH) CO emissions or reducing NH OH concentrations improves the agreement with CO surface observations, but reducing NH OH leads to a better comparison with MOPITT. Removing model biases in ozone and water vapor increases the simulated methane lifetime, but does not give the 20% reduction in NH OH suggested by our analysis the CO bias.
Atmos. Chem. Phys. Discuss., 15, 20305-20348, doi:10.5194/acpd-15-20305-2015, 2015
Change in turbopause altitude at 52 and 70° N
Summary: Turbulent energy dissipation rates are calculated using MF-radar signals from 70°N and 52°N for the period 2001-2014 inclusive, and are used to estimate turbopause altitudes. A positive trend in turbopause altitude is identified for 70°N in summer, but not in winter and not at 52°N. The turbopause altitude change between 2001 and 2014 can be used to hypothesize a corresponding change in atomic oxygen concentration.
Atmos. Chem. Phys. Discuss., 15, 20287-20304, doi:10.5194/acpd-15-20287-2015, 2015
Forty years of improvements in European air quality: the role of EU policy–industry interplay
Atmos. Chem. Phys. Discuss., 15, 20245-20285, doi:10.5194/acpd-15-20245-2015, 2015
Estimation of continuous anthropogenic CO2 using CO2, CO, δ13C(CO2) and Δ14C(CO2)
Summary: In this model sensitivity study we compare and evaluate the surrogate tracers CO2, CO, δ13C-CO2 and Δ14C-CO2 for estimating continuous anthropogenic CO2. The results can be used to optimize the measurement network design with respect to the partitioning of total CO2 into biospheric and anthropogenic CO2 contributions. This enables improvement and validation of highly resolved emission inventories using atmospheric observation and regional modelling.
Atmos. Chem. Phys. Discuss., 15, 20181-20243, doi:10.5194/acpd-15-20181-2015, 2015
Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming is highly dangerous
Summary: We suggest that ice sheet disintegration is a highly nonlinear process and poses a danger of rapid sea level rise. We find evidence in paleoclimate observations and in global climate simulations supporting the existence of amplifying feedback processes that would contribute to nonlinear ice sheet response. Modern observations reveal that these processes are already underway, including cooling of the Southern Ocean surface. We conclude that a 2°C limit on global warming is not a safe “guardrail".
Atmos. Chem. Phys. Discuss., 15, 20059-20179, doi:10.5194/acpd-15-20059-2015, 2015
Characterization of PM10 sources in the central Mediterranean
Atmos. Chem. Phys. Discuss., 15, 20013-20057, doi:10.5194/acpd-15-20013-2015, 2015
Development of an atmospheric N2O isotopocule model and optimization procedure, and application to source estimation
Summary: We developed an atmospheric N2O isotopocule model based on a chemistry-coupled atmospheric general circulation model and a simple method to optimize the model, and estimated the isotopic signatures of surface sources at the hemispheric scale. Data obtained from ground-based observations, measurements of firn air, and balloon and aircraft flights were used to optimize the long-term trends, interhemispheric gradients, and photolytic fractionation, respectively, in the model.
Atmos. Chem. Phys. Discuss., 15, 19947-20011, doi:10.5194/acpd-15-19947-2015, 2015
Cloud condensation nuclei activity, droplet growth kinetics and hygroscopicity of biogenic and anthropogenic Secondary Organic Aerosol (SOA)
Summary: This study investigated the cloud droplet activation behavior and hygroscopic growth of mixed anthropogenic and biogenic SOA (ABSOA) compared to pure biogenic SOA (BSOA) and pure anthropogenic SOA (ASOA). Cloud droplet activation behaviors of different types of SOA were similar. In contrast, the hygroscopicity of ASOA was higher than BSOA and ABSOA. ASOA components enhanced the hygroscopicity of the ABSOA. Yet this enhancement cannot be described by a linear mixing of pure SOA systems.
Atmos. Chem. Phys. Discuss., 15, 19903-19945, doi:10.5194/acpd-15-19903-2015, 2015
Plant surface reactions: an ozone defence mechanism impacting atmospheric chemistry
Summary: “Breathing” ozone can have harmful effects on sensitive vegetation when sufficient ozone enters the plant leaves through the stomatal pores. Here we show that cis-abienol, a semi-volatile organic compound secreted by the leaf hairs (trichomes) of various tobacco varieties, protects the leaves from “breathing" ozone. Ozone is efficiently removed by chemical reactions with cis-abienol at the plant surface, forming oxygenated VOC (formaldehyde and methyl vinyl ketone) that are released into the air
Atmos. Chem. Phys. Discuss., 15, 19873-19902, doi:10.5194/acpd-15-19873-2015, 2015
Variation of the radiative properties during black carbon aging: theoretical and experimental intercomparison
Atmos. Chem. Phys. Discuss., 15, 19835-19872, doi:10.5194/acpd-15-19835-2015, 2015
Hygroscopicity of nanoparticles produced from homogeneous nucleation in the CLOUD experiments
Summary: The hygroscopicity of nucleated nanoparticles was measured in the presence of sulfuric acid, sulfuric acid-dimethylamine, and sulfuric acid-organics derived from α-pinene oxidation during CLOUD 7 at CERN in 2012. The hygroscopicity parameter κ decreased with increasing particle size indicating decreasing acidity of particles.
Atmos. Chem. Phys. Discuss., 15, 19803-19833, doi:10.5194/acpd-15-19803-2015, 2015
Modeling particle nucleation and growth over northern California during the 2010 CARES campaign
Atmos. Chem. Phys. Discuss., 15, 19729-19801, doi:10.5194/acpd-15-19729-2015, 2015
Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign
Summary: The aim of this article is to present an experimental campaign over the Mediterranean focused on aerosol-radiation measurements and modeling. Results indicate an important atmospheric loading associated with a moderate absorbing ability of mineral dust. Observations suggest a complex vertical structure and size distributions characterized by large aerosols within dust plumes. The radiative effect is highly variable, with negative forcing over the Mediterranean and positive over northern Africa.
Atmos. Chem. Phys. Discuss., 15, 19615-19727, doi:10.5194/acpd-15-19615-2015, 2015
Dehydration effects from contrails in a coupled contrail–climate model
Atmos. Chem. Phys. Discuss., 15, 19553-19613, doi:10.5194/acpd-15-19553-2015, 2015
Updated ozone absorption cross section will reduce air quality compliance
Summary: As an air pollutant, O3 is monitored photometrically to assess compliance with air quality legislation. A recent study found a 1.8% reduction in its absorption cross section which would lead to an equivalent increase in observed O3 concentrations. We estimate this would increase the number of sites out of compliance with air quality regulations in the EU and US by 20%. We draw attention to how small changes in gas metrology impacts attainment and compliance with legal air quality standards.
Atmos. Chem. Phys. Discuss., 15, 19537-19551, doi:10.5194/acpd-15-19537-2015, 2015
Boundary layer new particle formation over East Antarctic sea ice – possible Hg driven nucleation?
Summary: An atmospheric new particle formation event that was observed in the pristine East Antarctic pack ice during a springtime voyage in 2012 is characterised in terms of formation and growth rates. Known nucleation mechanisms (e.g. those involving sulfate, iodine and organics) were unable to explain observations, however correlations with total gaseous mercury were found, leading to the suggestion of a possible mercury driven nucleation mechanism not previously described.
Atmos. Chem. Phys. Discuss., 15, 19477-19536, doi:10.5194/acpd-15-19477-2015, 2015
The contrasting roles of water and dust in controlling daily variations in radiative heating of the summertime Saharan Heat Low
Atmos. Chem. Phys. Discuss., 15, 19447-19476, doi:10.5194/acpd-15-19447-2015, 2015
Continuous measurements at the urban roadside in an Asian Megacity by Aerosol Chemical Speciation Monitor (ACSM): particulate matter characteristics during fall and winter seasons in Hong Kong
Summary: This study presents results of long-term submicron aerosol measurements in Hong Kong. The presented work covers fall and winter 2013. It serves to characterize aerosol in a densely-built up urban area of a typical Asian megacity with strong primary emission sources from vehicles and cooking and presents an in-depth analysis of distinct clean and heavily polluted time periods tied with meteorological data and other gas-phase species observed in the study period.
Atmos. Chem. Phys. Discuss., 15, 19405-19445, doi:10.5194/acpd-15-19405-2015, 2015
Aerosol dynamics within and above forest in relation to turbulent transport and dry deposition
Atmos. Chem. Phys. Discuss., 15, 19367-19403, doi:10.5194/acpd-15-19367-2015, 2015
Characterization of long-range transported Saharan dust at the Caribbean by dual-wavelength depolarization Raman lidar measurements
Summary: In June and July 2013 dual-wavelength lidar measurements were performed at Barbados to study long-range transported Saharan dust across the Atlantic Ocean, and to investigate transport-induced changes. In the focus our measurements are the intensive optical properties, the lidar ratio and the particle linear depolarization ratio. While the lidar ratio shows no differences compared to the values of fresh Saharan dust, the particle linear depolarization ratio shows slight differences.
Atmos. Chem. Phys. Discuss., 15, 19325-19366, doi:10.5194/acpd-15-19325-2015, 2015
Influence of tropical cyclones on tropospheric ozone: possible implication
Summary: Highlights of the present study : (1) First observational evidence of enhanced upper tropospheric ozone during cyclonic and sever cyclonic storms (2) Enhancement of surface ozone after ever cyclonic storms (3) Intrusion of stratospheric air into the troposphere
Atmos. Chem. Phys. Discuss., 15, 19305-19323, doi:10.5194/acpd-15-19305-2015, 2015
A new indictor on the impact of large-scale circulation on wintertime particulate matter pollution over China
Atmos. Chem. Phys. Discuss., 15, 19275-19304, doi:10.5194/acpd-15-19275-2015, 2015
Development of a high temporal–spatial resolution vehicle emission inventory based on NRT traffic data and its impact on air pollution in Beijing – Part 2: Impact of vehicle emission on urban air quality
Summary: 1. Chinese Unified Atmospheric Chemistry Environment (CUACE) model had good performance of pollutants concentration simulation. 2. CUACE simulation has been improved by using high temporal-spatial resolution vehicle emission inventory. 3. The mean vehicle emission contribution is 55.4% and 48.5% for NO2, while 5.4% and 10.5% for PM2.5 in July and December 2013, respectively.
Atmos. Chem. Phys. Discuss., 15, 19239-19273, doi:10.5194/acpd-15-19239-2015, 2015
Changes in chemical components of aerosol particles in different haze regions in China from 2006 to 2013 and contribution of meteorological factors
Summary: No obvious changes were found in annual mean concentrations of major chemical components and PM10 in 2013, relative to 2012. But wintertime mass were quite different; approximately 60% of the winter mass increase from 2012 to 2013 can be attributed to severe meteorological conditions in the HBP area, and mass of chemical components exhibited a decline during 2006 to 2010, and then a rise till 2013. Coal-combustion was still the largest anthropogenic source of aerosol pollution in 2013 in China.
Atmos. Chem. Phys. Discuss., 15, 19197-19238, doi:10.5194/acpd-15-19197-2015, 2015
Evaluation of the Australian Community Climate and Earth-System Simulator Chemistry-Climate Model
Atmos. Chem. Phys. Discuss., 15, 19161-19196, doi:10.5194/acpd-15-19161-2015, 2015
Can we explain the observed methane variability after the Mount Pinatubo eruption?
Summary: We quantify the processes responsible for methane growth rate variability in the period 1990 to 1995, a period with variations in climate and radiation due to the Pinatubo eruption. We find significant contributions from changes in the methane emission from wetlands, and in the methane removal by OH caused by stratospheric aerosols, by the decrease in temperature and water vapour, by stratospheric ozone depletion and by changes in emissions of CO and NMVOC.
Atmos. Chem. Phys. Discuss., 15, 19111-19160, doi:10.5194/acpd-15-19111-2015, 2015
Observed high-altitude warming and snow cover retreat over Tibet and the Himalayas enhanced by black carbon aerosols
Summary: We show that black carbon aerosol pollution is likely the dominating factor in causing the accelerated retreat of snow pack. The simulated snow fraction and surface albedo change at the surface, as well as the enhanced warming at higher elevations, are remarkably similar to observations. The fundamental reason for the model’s ability to simulate the observed trends is that in this study, we replace the model simulated black carbon forcing with one that is constrained by observations.
Atmos. Chem. Phys. Discuss., 15, 19079-19109, doi:10.5194/acpd-15-19079-2015, 2015
Spectral optical layer properties of cirrus from collocated airborne measurements – a feasibility study
Atmos. Chem. Phys. Discuss., 15, 19045-19077, doi:10.5194/acpd-15-19045-2015, 2015
Constraints on methane emissions in North America from future geostationary remote sensing measurements
Summary: This work provides new insight into the observational constraints provided by current low earth orbit (LEO) and future potential geostationary (GEO) satellite mission on methane emissions in North America. Using efficient numerical tools, the information content (error reductions, spatial resolution of the constraints) of methane inversions using different instrument configurations (TIR, SWIR and multi-spectral) was estimated at model grid scale resolution (0.5 degx0.7deg).
Atmos. Chem. Phys. Discuss., 15, 19017-19044, doi:10.5194/acpd-15-19017-2015, 2015
The impact of snow nitrate photolysis on boundary layer chemistry and the recycling and redistribution of reactive nitrogen across Antarctica in a global chemical transport model
Summary: A snowpack actinic flux parameterization and a nitrate photolysis scheme are incorporated into a global chemical transport model (GEOS-Chem). This novel modeling framework is used to examine the implications of snow nitrate photolysis for boundary layer chemistry, the recycling and redistribution of reactive nitrogen across Antarctica, and the preservation of nitrate in Antarctic ice cores.
Atmos. Chem. Phys. Discuss., 15, 18963-19015, doi:10.5194/acpd-15-18963-2015, 2015
Impacts of aviation fuel sulfur content on climate and human health
Summary: Using a coupled tropospheric chemistry-aerosol microphysics model this research paper investigates the effect of variations in aviation fuel sulfur content (FSC) on surface PM2.5 concentrations, increases in aviation-induced premature mortalities, low-level cloud condensation nuclei and radiative effect. When investigating the climatic impact of variations in FSC the ozone direct radiative effect, aerosol direct radiative effect and aerosol cloud albedo effect are quantified.
Atmos. Chem. Phys. Discuss., 15, 18921-18961, doi:10.5194/acpd-15-18921-2015, 2015
Impacts of Amazonia biomass burning aerosols assessed from short-range weather forecasts
Atmos. Chem. Phys. Discuss., 15, 18883-18919, doi:10.5194/acpd-15-18883-2015, 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. Discuss., 15, 18839-18882, doi:10.5194/acpd-15-18839-2015, 2015
High-resolution inventory of technologies, activities, and emissions of coal-fired power plants in China from 1990 to 2010
Summary: This is the first study that emissions from China’s coal-fired power plants were estimated at unit level for a 20-yr period. This new emission inventory is constructed from a unit-based database compiled in this work, named the China coal-fired Power plant Emissions Database (CPED), which includes detailed information on the technologies, activity data, operation situation, emission factors, and locations of individual units.
Atmos. Chem. Phys. Discuss., 15, 18787-18837, doi:10.5194/acpd-15-18787-2015, 2015
Atmospheric polarimetric effects on GNSS Radio Occultations: the ROHP-PAZ field campaign
Atmos. Chem. Phys. Discuss., 15, 18747-18785, doi:10.5194/acpd-15-18747-2015, 2015
Advantages of city-scale emission inventory for urban air quality research and policy: the case of Nanjing, a typical industrial city in the Yangtze River Delta, China
Summary: A high-resolution emission inventory of air pollutants and CO2 for Nanjing, a typical city in eastern China, is developed incorporating the best available local information from onsite survey. The temporal and spatial distribution of the emissions and the correlation between specific species of the inventory are assessed by comparisons with observations and other inventories at larger spatial scale. The emission inventory provides a basis to consider the quality of instrumental observations.
Atmos. Chem. Phys. Discuss., 15, 18691-18746, doi:10.5194/acpd-15-18691-2015, 2015
Nucleation and growth of sub-3 nm particles in the polluted urban atmosphere of a megacity in China
Atmos. Chem. Phys. Discuss., 15, 18653-18690, doi:10.5194/acpd-15-18653-2015, 2015
Comparison of vertical aerosol extinction coefficients from in-situ and LIDAR measurements
Atmos. Chem. Phys. Discuss., 15, 18609-18651, doi:10.5194/acpd-15-18609-2015, 2015
The influence of synoptic weather regimes on UK air quality: regional model studies of tropospheric column NO2
Atmos. Chem. Phys. Discuss., 15, 18577-18607, doi:10.5194/acpd-15-18577-2015, 2015
New characteristics of submicron aerosols and factor analysis of combined organic and inorganic aerosol mass spectra during winter in Beijing
Atmos. Chem. Phys. Discuss., 15, 18537-18576, doi:10.5194/acpd-15-18537-2015, 2015
On the ability of RegCM4 regional climate model to simulate surface solar radiation patterns over Europe: an assessment using satellite-based observations
Summary: It is shown here that RegCM4 regional climate model simulates adequately surface solar radiation (SSR) over Europe but over/under-estimates significantly several parameters that determine the transmission of solar radiation in the atmosphere. The agreement between RegCM4 and satellite-based SSR observations is actually a result of the contradicting effect of these parameters. We suggest that there should be a reassessment of the way these parameters are represented within this and other models.
Atmos. Chem. Phys. Discuss., 15, 18487-18535, doi:10.5194/acpd-15-18487-2015, 2015
Impact of future land cover changes on HNO3 and O3 surface dry deposition
Summary: Dry deposition is a key component of surface-atmosphere exchange of compounds, acting as a sink for several chemical species and strongly driven by meteorological factors, chemical properties of the trace gas considered and land surface properties. The objective of our study is to investigate the impact of vegetation distribution change, which is still not very well quantified, on the dry deposition of key atmospheric species: ozone and nitric acid vapor.
Atmos. Chem. Phys. Discuss., 15, 18459-18485, doi:10.5194/acpd-15-18459-2015, 2015
Air quality and radiative impacts of Arctic shipping emissions in the summertime in northern Norway: from the local to the regional scale
Atmos. Chem. Phys. Discuss., 15, 18407-18457, doi:10.5194/acpd-15-18407-2015, 2015
Quantifying atmospheric nitrogen deposition through a nationwide monitoring network across China
Summary: The annual average concentrations (1.3-47.0µg N m-3) and dry plus wet deposition fluxes (2.9-75.2kg N ha-1 yr-1) of inorganic Nr species ranked by region as North China > Southeast China > Southwest China > Northeast China > Northwest China > the Tibetan Plateau or by land use as urban > rural > background sites, reflecting the impact of anthropogenic Nr emission. Average dry and wet N deposition fluxes were 18.5 and 19.3kg N ha-1 yr-1, respectively, across China.
Atmos. Chem. Phys. Discuss., 15, 18365-18405, doi:10.5194/acpd-15-18365-2015, 2015
The diurnal cycle of rainfall over New Guinea in convection-permitting WRF simulations
Summary: Our paper highlights the importance of terrain, coastal and convectively induced gravity waves in contributing to the diurnal cycle of rainfall over the Maritime Continent, especially the offshore precipitation maxima adjacent to linearly oriented coastlines. We find that days with offshore propagating systems are largely controlled by background conditions (more mid-tropospheric moisture, more CAPE and more low-level moisture flux convergence) as opposed to days without offshore propagation.
Atmos. Chem. Phys. Discuss., 15, 18327-18363, doi:10.5194/acpd-15-18327-2015, 2015
Enhanced internal gravity wave activity and breaking over the Northeastern Pacific/Eastern Asian region
Summary: In this study, we present a discovery of an internal gravity wave activity and breaking hotspot collocated with an area of anomalously low annual cycle amplitude and specific dynamics in the stratosphere over the Northeastern Pacific/Eastern Asia coastal region. The reasons, why this particular IGW activity hotspot was not discovered before nor the specific dynamics of this region was pointed out, are discussed together with possible consequences on the middle atmospheric dynamics and transport.
Atmos. Chem. Phys. Discuss., 15, 18285-18325, doi:10.5194/acpd-15-18285-2015, 2015
Fourteen months of on-line measurements of the non-refractory submicron aerosol at the Jungfraujoch (3580 m a.s.l.) – chemical composition, origins and organic aerosol sources
Summary: This manuscript presents the first long-term (14 months) and highly time resolved (10 min) measurements of NR-PM1 aerosol chemical composition at a high-altitude site (JFJ, Switzerland, 3580m asl). The elevated location allowed the investigation of free tropospheric aerosol year round. Total and relative mass loadings, diurnal variations as well as seasonal variations are discussed together with geographical origin, organic aerosol sources and the influence of the planetary boundary layer.
Atmos. Chem. Phys. Discuss., 15, 18225-18284, doi:10.5194/acpd-15-18225-2015, 2015
The origins of ice crystals measured in mixed phase clouds at High-Alpine site Jungfraujoch
Summary: The paper explores the microphysical structure of clouds at high-alpine measurement site Jungfraujoch, Switzerland. High concentrations of ice crystals were measured by a range of instruments. The presence of these high concentrations could not be explained through conventional understanding of ice formation processes in clouds and the possibility that the surface provides a significant source of ice crystals is investigated.
Atmos. Chem. Phys. Discuss., 15, 18181-18224, doi:10.5194/acpd-15-18181-2015, 2015
Thermodynamic derivation of the energy of activation for ice nucleation
Summary: This paper describes the process of transfer of water molecules between the liquid and the ice during the early stages of ice formation. Using concepts of non-reversible thermodynamics it is shown that the activation energy can be defined in terms of the bulk self-diffusivity of water and the probability of interface transfer. Application of this model into classical nucleation theory shows good agreement of measured nucleation rates with experimental results for temperatures as low as 190K.
Atmos. Chem. Phys. Discuss., 15, 18151-18179, doi:10.5194/acpd-15-18151-2015, 2015
Aerosol size distribution seasonal characteristics measured in Tiksi, Russian Arctic
Atmos. Chem. Phys. Discuss., 15, 18109-18149, doi:10.5194/acpd-15-18109-2015, 2015
Riming in winter alpine snowfall during CLACE 2014: polarimetric radar and in-situ observations
Summary: This study investigates the microphysics of winter alpine snowfall occurring in mixed-phase clouds in an inner-Alpine valley during CLACE2014. From polarimetric radar and in-situ observations, riming is shown to be an important process leading to more intense snowfall. Riming is usually associated with more intense turbulence providing supercooled liquid water. Distinct features are identified in the vertical structure of polarimetric radar variables.
Atmos. Chem. Phys. Discuss., 15, 18065-18108, doi:10.5194/acpd-15-18065-2015, 2015
Observed spatial variability of boundary-layer turbulence over flat, heterogeneous terrain
Atmos. Chem. Phys. Discuss., 15, 18011-18064, doi:10.5194/acpd-15-18011-2015, 2015
Chemical characterization of fine organic aerosol for source apportionment at Monterrey, Mexico
Summary: The identified organic compound classes demonstrated that anthropogenic sources were dominant. Gasoline- and diesel-powered vehicles are the main emission sources (CMB = 64%) of this class of organic compounds in PM2.5. Other pyrogenic sources such as coal, grass, and wood combustion as well as meat cooking operations were also identified as contributors to the fine OA. Aging of primary emissions and the SOA from biogenic volatile organic compounds due to photochemical activity and transport.
Atmos. Chem. Phys. Discuss., 15, 17967-18010, doi:10.5194/acpd-15-17967-2015, 2015
Cold smoke: smoke-induced density currents cause unexpected smoke transport near large wildfires
Atmos. Chem. Phys. Discuss., 15, 17945-17966, doi:10.5194/acpd-15-17945-2015, 2015
The contribution of oceanic halocarbons to marine and free troposphere air over the tropical West Pacific
Summary: Our results show that a convective, well-ventilated boundary layer and intense convection led to the low atmospheric mixing ratios in the boundary layer despite the high oceanic emissions in coastal areas of the South China and Sulu Seas.
Atmos. Chem. Phys. Discuss., 15, 17887-17943, doi:10.5194/acpd-15-17887-2015, 2015
Observation of isoprene hydroxynitrates in the Southeastern United States and implications for the fate of NOx
Summary: Hydroxynitrates from isoprene oxidation were quantified both in the laboratory and the field studies. The yield of hydroxynitrates 9(+4/-3)% derived from chamber experiments was applied in a zero-dimensional model to simulate the production and loss of isoprene hydroxynitrates in ambient environmental during the 2013 Southern Oxidant and Aerosol Study (SOAS). NOx was determined to be the limiting factor for the formation of isoprene hydroxynitrates during SOAS.
Atmos. Chem. Phys. Discuss., 15, 17843-17886, doi:10.5194/acpd-15-17843-2015, 2015
Hygroscopic behavior of NaCl–MgCl2 mixture particles as nascent sea-spray aerosol surrogates and observation of efflorescence during humidifying process
Summary: Pure MgCl2 particles and NaCl-MgCl2 mixed particles are systematically investigated to observe their hygroscopic behavior, derive experimental phase diagrams, and obtain chemical micro-structures. This work provides new interesting revelations regarding the efflorescence of MgCl2 hydrates during dehydration and also humidification. The observation of an aqueous phase over a wider RH range for NaCl-MgCl2 mixture particles indicates their more probable heterogeneous chemistry than NaCl particles.
Atmos. Chem. Phys. Discuss., 15, 17797-17842, doi:10.5194/acpd-15-17797-2015, 2015
Sensitivity of polar stratospheric cloud formation to changes in water vapour and temperature
Summary: Our sensitivity studies based on air parcel trajectories confirm that Polar stratospheric cloud (PSC) formation is quite sensitive to water vapour and temperature changes. Considering water vapour time series from satellite measurements we do not find a consistent, significant trend in water vapour in the lower stratosphere during the past 15 years (2000-2014). Thus, the severe denitrification observed in 2010/2011 cannot be directly related to increases in stratospheric water vapour.
Atmos. Chem. Phys. Discuss., 15, 17743-17796, doi:10.5194/acpd-15-17743-2015, 2015
Assessment of multi-decadal WRF-CMAQ simulations for understanding direct aerosol effects on radiation "brightening" in the United States
Summary: This study attempts to determine the consequences of the changes in tropospheric aerosol burden arising from substantial reductions in emissions of SO2 and NOx associated with control measures under the Clean Air Act especially on trends in solar radiation.Comparisons of model results with observations of aerosol optical depth, aerosol concentration and radiation demonstrate that the coupled WRF-CMAQ model is capable of replicating the trends well even through it tends to underestimate the AOD.
Atmos. Chem. Phys. Discuss., 15, 17711-17742, doi:10.5194/acpd-15-17711-2015, 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. Discuss., 15, 17651-17709, doi:10.5194/acpd-15-17651-2015, 2015
Biomass burning emissions of trace gases and particles in marine air at Cape Grim, Tasmania, 41° S
Summary: Biomass burning (BB) plumes have been opportunistically measured at the Cape Grim Baseline Station in Tasmania, Australia. We show the substantial impact that BB plumes have on the composition of marine air, and the significant changes that occur as the plume is diluted and interacts with other emission sources. We provide new trace gas and particle emission factors for temperate southern Australia. A major short-lived enhancement in trace gas emissions is attributed to a minor rainfall event.
Atmos. Chem. Phys. Discuss., 15, 17599-17649, doi:10.5194/acpd-15-17599-2015, 2015
Modelling marine emissions and atmospheric distributions of halocarbons and DMS: the influence of prescribed water concentration vs. prescribed emissions
Summary: Marine produced short-lived trace gases such as halocarbons and DMS significantly impact atmospheric chemistry. To assess this impact on ozone depletion and the radiative budget, it is critical that their marine emissions in atmospheric chemistry models are quantified as accurately as possible. We show that calculating emissions online with an interactive atmosphere improves the agreement with current observations and should be employed regularly in models where marine sources are important.
Atmos. Chem. Phys. Discuss., 15, 17553-17598, doi:10.5194/acpd-15-17553-2015, 2015
Effect of retreating sea ice on Arctic cloud cover in simulated recent global warming
Atmos. Chem. Phys. Discuss., 15, 17527-17552, doi:10.5194/acpd-15-17527-2015, 2015
Wet deposition of atmospheric inorganic nitrogen at five remote stations on the Tibetan Plateau
Summary: We investigated inorganic N deposition wet deposition at five stations on the Tibetan Plateau. Combining our observations with that in previous studies, the average wet deposition of NH4+-N, NO3−-N, and inorganic N on the Tibetan Plateau was estimated to be 1.17, 0.58 and 1.75 kg N ha−1 yr−1, respectively. The inorganic N deposition for the entire Tibetan Plateau in previous studies, either through model simulations or interpolations based on limited observations, has been highly overestimated.
Atmos. Chem. Phys. Discuss., 15, 17491-17526, doi:10.5194/acpd-15-17491-2015, 2015
Reactive uptake of ammonia to secondary organic aerosols: kinetics of organonitrogen formation
Atmos. Chem. Phys. Discuss., 15, 17449-17490, doi:10.5194/acpd-15-17449-2015, 2015
A process-based 222Rn flux map for Europe and its comparison to long-term observations
Summary: Detailed 222Rn flux maps are a prerequisite for the use of radon in atmospheric transport studies. We present a high-resolution 222Rn flux map for Europe, based on a parameterization of 222Rn production and transport in the soil. Spatial variations in 222Rn exhalation rates are determined by soil uranium content, water table depth and soil texture. Temporal variations are related to soil moisture variations as the diffusion in the soil depends on available air-filled pore space.
Atmos. Chem. Phys. Discuss., 15, 17397-17448, doi:10.5194/acpd-15-17397-2015, 2015
Organic peroxide and OH formation in aerosol and cloud water: laboratory evidence for this aqueous chemistry
Summary: This paper demonstrates organic peroxide formation during aqueous photooxidation of methylglyoxal using ultra high resolution Fourier Transform Ion Cyclotron Resonance electrospray ionization mass spectrometry (FTICR-MS). Then, we provide simulation results of organic peroxide/peroxyhemiacetal formation in clouds and wet aerosols and discuss organic peroxides as a source of condensed-phase OH radicals and as a contributor to aqueous secondary organic aerosol (SOA).
Atmos. Chem. Phys. Discuss., 15, 17367-17396, doi:10.5194/acpd-15-17367-2015, 2015
Hygroscopic properties and cloud condensation nuclei activation of limonene-derived organosulfates and their mixtures with ammonium sulfate
Atmos. Chem. Phys. Discuss., 15, 17317-17365, doi:10.5194/acpd-15-17317-2015, 2015
A two-dimensional volatility basis set – Part 3: Prognostic modeling and NOx dependence
Summary: NOx is formed under high-temperature conditions such as combustion. When NOx enters the atmosphere, it alters the chemistry of organic emissions and can form organonitrates. Depending on the conditions, NOx may increase or decrease resulting aerosol concentrations. We expanded the two-dimensional volatility basis set (2D-VBS) to model organonitrates and the effect on aerosol concentrations. We discuss the mathematical framework of the model and include the code in the supplemental material.
Atmos. Chem. Phys. Discuss., 15, 17283-17316, doi:10.5194/acpd-15-17283-2015, 2015
Estimating ground-level PM2.5 in Eastern China using aerosol optical depth determined from the GOCI Satellite Instrument
Summary: 1. GOCI (Geostationary Ocean Color Imager) retrieval of AOD is consistent with AERONET AOD (RMSE=0.08-0.1) 2. GOCI-derived PM2.5 is in significant agreement with in-situ observations (R=0.81, MFB = 13%) 3. Population-weighted GOCI-derived PM2.5 over eastern China for 2013 is 53.8 μg/m3, threatening the health of its 603 million residents 4. Secondary inorganics (SO42-, NO3-, NH4+) & organic matter are the most significant components of GOCI-derived PM2.5
Atmos. Chem. Phys. Discuss., 15, 17251-17281, doi:10.5194/acpd-15-17251-2015, 2015
How large-scale subsidence affects stratocumulus transitions
Summary: A large-eddy simulation model is used to show that a weakening of the large-scale subsidence, which is associated with a future warmer climate, leads to a delay of the moment of break up of stratocumulus clouds during subtropical stratocumulus transitions. To understand what causes this delay, an novel analysis method is used to distil the contributions of individual physical processes to the evolution of the stratocumulus cloud thickness.
Atmos. Chem. Phys. Discuss., 15, 17229-17250, doi:10.5194/acpd-15-17229-2015, 2015
PM2.5 water-soluble elements in the southeastern United States: automated analytical method development, spatiotemporal distributions, source apportionment, and implications for heath studies
Summary: This work presented a new method of quantifying water-soluble elements in PM2.5 aqueous extracts (N~500) with an X-ray fluorescence analyzer. The results indicate that water-soluble elements had marked spatial and temporal patterns. Four sources were resolved: brake/tire wear, biomass burning, secondary formation, and mineral dust. The findings have informed studies on aerosol oxidative potential and provided insights into the health effects of water-soluble metals, especially Cu, Fe, Mn and Zn.
Atmos. Chem. Phys. Discuss., 15, 17189-17227, doi:10.5194/acpd-15-17189-2015, 2015
Spatial and temporal variability of clouds and precipitation over Germany: multiscale simulations across the "gray zone"
Atmos. Chem. Phys. Discuss., 15, 17135-17187, doi:10.5194/acpd-15-17135-2015, 2015
Source analysis of peroxyacetyl nitrate (PAN) in Guangzhou, China: a yearlong observation study
Summary: Photochemical smog has been a major cause of air pollution in Guangzhou, one of megacities in China. This study firstly examined the source of peroxyacetyl nitrate in Guangzhou based on a yearlong data set including PAN, ozone, nitrogen oxides and non-methane hydrocarbons. The results suggest regional air mass transport of pollutants had a major impact on the PAN concentrations in Guangzhou area, which will provide useful information for more effectively managing the air quality of Guangzhou.
Atmos. Chem. Phys. Discuss., 15, 17093-17133, doi:10.5194/acpd-15-17093-2015, 2015
Effects of emission reductions on organic aerosol in the southeastern United States
Summary: Fifteen years of gas and particle measurements at eight monitoring sites comprising the Southeastern Aerosol Research and Characterization (SEARCH) network offer insights into the sources of organic aerosol in the southeastern United States. Between 1999 and 2013, mean organic aerosol concentrations declined due to decreasing particle emissions from motor vehicles and to less secondary organic aerosol with declining emissions of sulfur dioxide, nitrogen oxides, and volatile organic compounds.
Atmos. Chem. Phys. Discuss., 15, 17051-17092, doi:10.5194/acpd-15-17051-2015, 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 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. Discuss., 15, 16985-17050, doi:10.5194/acpd-15-16985-2015, 2015
Long-range transport of black carbon to the Pacific Ocean and its dependence on aging timescale
Summary: We tag BC emissions from 13 source regions around the globe in a global chemical transport model MOZART-4, and optimize the aging timescale for each source region by minimizing errors in vertical profiles of BC mass mixing ratios between simulations and HIAPER Polo-to-Pole Observations（HIPPO）. We find that the optimized aging timescale of BC varies significantly by region and season. Our simulations indicate that BC lifetime increases nearly linearly with aging timescale for all source regions.
Atmos. Chem. Phys. Discuss., 15, 16945-16983, doi:10.5194/acpd-15-16945-2015, 2015
Radiative and thermodynamic responses to aerosol extinction profiles during the pre-monsoon month over South Asia
Atmos. Chem. Phys. Discuss., 15, 16901-16943, doi:10.5194/acpd-15-16901-2015, 2015
On retrieving refractive index of dust-like particles using shape distributions of ellipsoids
Summary: Combinations of simple mathematical model shapes called ellipsoids are used in many remote sensing and modeling applications to denote dust particles. In this study we investigate how accurately various physical parameters can be retrieved by using ellipsoids. The results show that using ellipsoids can lead to wrong results, while at the same time seeming like they work well. This means that extreme care should be used when using ellipsoids for dust, and extra validation measures should be used.
Atmos. Chem. Phys. Discuss., 15, 16861-16900, doi:10.5194/acpd-15-16861-2015, 2015
On measurements of aerosol–gas composition of the atmosphere during two expeditions in 2013 along Northern Sea Route
Summary: We discuss the spatiotemporal variations in aerosol characteristics, measured along Northern Sea Route in cruises of RVs "Akademik Fedorov" and "Professor Khljustin". The variability ranges of the average aerosol parameters in separate seas and regions were: from 2.5 to 24 cm-3 for number concentration of particles; from 830 to 2970 ng·m-3 for aerosol mass concentrations; from 20 до 150 ng·m-3 for Black Carbon mass concentrations; and from 0.03 to 0.19 for aerosol optical depth (0.5 um).
Atmos. Chem. Phys. Discuss., 15, 16775-16859, doi:10.5194/acpd-15-16775-2015, 2015
Variations of surface ozone at Ieodo Ocean Research Station in the East China Sea and influence of Asian outflows
Summary: In East Asia, emissions of O3 precursors have gradually increased and O3 concentration are expected to increase in the near future. Ieodo Ocean Research Station (IORS) located in the East China Sea is a unique research tower suitable for observing continental outflows from East Asia. In this study, we present long-term measurements of O3 at IORS, describe their characteristic variations, and evaluate the continental influence on the regional background concentrations of O3.
Atmos. Chem. Phys. Discuss., 15, 16747-16774, doi:10.5194/acpd-15-16747-2015, 2015
Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the arctic troposphere
Summary: Sea salt aerosols (SSA) are dominant particles in the arctic atmosphere. Our result suggests that the hydrophilic MgCl2 coating in fresh SSA likely intrigued the heterogeneous reactions at the beginning of SSA and acidic gases in the arctic. The content of organic matter increased in the aged SSA compared with the fresh SSA, which suggest organic acids (beside inorganic acids) participate in the aging of SSA in the arctic.
Atmos. Chem. Phys. Discuss., 15, 16715-16745, doi:10.5194/acpd-15-16715-2015, 2015
Influence of the ambient humidity on the concentration of natural deposition ice nuclei
Summary: This work deals with the origin and nature of atmospheric ice nuclei (IN). An accurate determination of the atmospheric IN concentration is relevant since they induce freezing in clouds thus initiating an efficient mechanism for cloud particles to reach a precipitating size. The effect of the relative humidity at ground level on the IN concentration was analyzed and discussed.
Atmos. Chem. Phys. Discuss., 15, 16697-16714, doi:10.5194/acpd-15-16697-2015, 2015
Ozonesonde profiles from the West Pacific Warm Pool
Summary: This paper reports the results of a field campaign with ozonesondes held in Manus Island, Papua New Guinea in February 2014. Particular attention is paid to the background current correction for the ozonesondes. We show that the ozonesonde profiles compare very well with near-coincident aircraft measurements, and show no sign of the extremely low ozone concentrations (< 5 ppbv) reported by previous papers. The minimum repeatable ozone concentration just below the tropopause was 12 ppbv.
Atmos. Chem. Phys. Discuss., 15, 16655-16696, doi:10.5194/acpd-15-16655-2015, 2015
An online aerosol retrieval algorithm using OMI near-UV observations based on the optimal estimation method
Summary: The aerosol retrieval and error analysis algorithm using the OMI measurements based on the optimal estimation method was developed in this study. The aerosol retrievals were validated using the DRAGON campaign products. The estimated errors of the retrievals well represented the actual biases between retrieval and AERONET measurements. The retrievals with thier estimated uncertainties are exprected to be valuable for the relevant studies such as trace gas retrieval and data assimilations.
Atmos. Chem. Phys. Discuss., 15, 16615-16654, doi:10.5194/acpd-15-16615-2015, 2015
High ice water content at low radar reflectivity near deep convection – Part 2: Evaluation of microphysical pathways in updraft parcel simulations
Summary: An updraft parcel model with size-resolved microphysics is used to investigate microphysical pathways leading to ice water content > 2g m-3 with mass median area-equivalent diameter of 200-300micron reported at ~11km in tropical deep convection. Parcel simulations require substantial source of small crystals at temperatures > ~-10deg C growing by vapor deposition. Warm rain in weaker updrafts paradoxically leads to greater ice mass owing to reduced competition for available water vapor.
Atmos. Chem. Phys. Discuss., 15, 16551-16613, doi:10.5194/acpd-15-16551-2015, 2015
High ice water content at low radar reflectivity near deep convection – Part 1: Consistency of in situ and remote-sensing observations with stratiform rain column simulations
Summary: Airbus measurements at elevations circa 11 km within large storm systems near Cayenne, Darwin and Santiago indicate ice mass distributed over area-equivalent diameters of 100-500 µm. Profiler-observed radar reflectivity and mean Doppler velocity under similar conditions are found to be consistent with measurements and with 1D simulations of steady-state stratiform rain columns initialized with observed ice size distributions. Results motivate investigation of ice formation pathways in Part II.
Atmos. Chem. Phys. Discuss., 15, 16505-16550, doi:10.5194/acpd-15-16505-2015, 2015
Does GOSAT capture the true seasonal cycle of XCO2?
Atmos. Chem. Phys. Discuss., 15, 16461-16503, doi:10.5194/acpd-15-16461-2015, 2015
New particle-dependent parameterizations of heterogeneous freezing processes: sensitivity studies of convective clouds with an air parcel model
Atmos. Chem. Phys. Discuss., 15, 16401-16460, doi:10.5194/acpd-15-16401-2015, 2015
Trend analysis of the 20 years time series of stratospheric ozone profiles observed by the GROMOS microwave radiometer at Bern
Summary: GROMOS (GROund-based Millimeterwave Ozone Spectrometer) has provided ozone profiles for the NDACC (Network for the Detection of Atmospheric Composition Change) at Bern since 1994. We performed a trend analysis of our 20 years time series of stratospheric ozone profiles with a multilinear parametric trend estimation method. With our estimated ozone trends we are able to support the stratospheric ozone turnaround. Besides a statistically significant negative trend in the lower mesosphere.
Atmos. Chem. Phys. Discuss., 15, 16371-16400, doi:10.5194/acpd-15-16371-2015, 2015
Ice water content vertical profiles of high-level clouds: classification and impact on radiative fluxes
Summary: *) We discuss the shape of ice water content (IWC) vertical profiles in high ice clouds and its effect on radiative properties of these clouds, both in short- and in long-wave bands (SW and LW). *) We suggest a set of primitive shapes (rectangular, isosceles trapezoid, lower and upper triangle) and propose a statistical parameterization using ice water path (IWP) as a single parameter. *) We estimate and explain simulated differences in LW/SW atmospheric radiances for suggested IWC shapes.
Atmos. Chem. Phys. Discuss., 15, 16325-16369, doi:10.5194/acpd-15-16325-2015, 2015
Ice nucleating particles at a coastal marine boundary layer site: correlations with aerosol type and meteorological conditions
Atmos. Chem. Phys. Discuss., 15, 16273-16323, doi:10.5194/acpd-15-16273-2015, 2015
Organic nitrate aerosol formation via NO3 + BVOC in the Southeastern US
Summary: This paper reports atmospheric gas- and aerosol-phase field measurements from the southeastern United States in summer 2013 to demonstrate that the oxidation of biogenic volatile organic compounds by nitrate radical produces a substantial amount of secondary organic aerosol in this region. This process, driven largely by monoterpenes, results in a comparable aerosol nitrate production rate to inorganic nitrate formation by heterogeneous uptake of HNO3 onto dust particles.
Atmos. Chem. Phys. Discuss., 15, 16235-16272, doi:10.5194/acpd-15-16235-2015, 2015
Light absorption properties of laboratory generated tar ball particles
Summary: Tar balls (TBs) are a specific particle type which is abundant in the global troposphere, in particular in biomass smoke plumes. These particles belong to the family of atmospheric brown carbon (BrC) which can absorb light in the visible range of the solar spectrum. The refractive index of TBs falls closer to those of soot than to other light-absorbing species such as humic-like substances. These findings may have substantial influence on the understanding of global radiative energy fluxes.
Atmos. Chem. Phys. Discuss., 15, 16215-16234, doi:10.5194/acpd-15-16215-2015, 2015
Absorption coefficient of urban aerosol in Nanjing, west Yangtze River Delta of China
Atmos. Chem. Phys. Discuss., 15, 16175-16213, doi:10.5194/acpd-15-16175-2015, 2015
Challenges of parameterizing CCN due to changes in particle physicochemical properties: implications from observations at a suburban site in China
Atmos. Chem. Phys. Discuss., 15, 16141-16174, doi:10.5194/acpd-15-16141-2015, 2015
Impact of environmental moisture on tropical cyclone intensification
Atmos. Chem. Phys. Discuss., 15, 16111-16139, doi:10.5194/acpd-15-16111-2015, 2015
Observations of cloud microphysics and ice formation during COPE
Summary: We present microphysics observations of cumulus clouds measured over southwest England during COPE in summer 2013. Detailed sampling focused on an isolated liquid cloud that glaciated as it matured to merge with a band of cloud downwind. We demonstrate that freezing of supercooled drizzle drops not only provides a pathway to advance the onset of the Hallett-Mossop process, it also accelerates glaciation and the formation of precipitation once it has begun.
Atmos. Chem. Phys. Discuss., 15, 16049-16110, doi:10.5194/acpd-15-16049-2015, 2015
Impact of particle shape on the morphology of noctilucent clouds
Summary: - For the first time, the shape of noctilucent cloud particles is analyzed with a 3-D Lagrangian model - Three-color lidar measurements are compared directly to optical modeling of NLC simulations with non-spherical shapes - Mix of elongated and flattened cylindrical ice particles consistent with measurements - Comparison best if flattened particles form a majority, with mean axis ratio around 2.8 - NLC from cylindrical particles slightly brighter, consists of fewer but larger ice particles
Atmos. Chem. Phys. Discuss., 15, 16019-16048, doi:10.5194/acpd-15-16019-2015, 2015
Tropical, oceanic, deep convective cloud morphology as observed by CloudSat
Summary: Presented in this paper are further results from a recently developed CloudSat tropical deep convective cloud database first detailed in Igel et al (2014). Length scales of the "average" mature tropical deep convective cloud are discussed. These scales are then used to provide insight into the relationship between the upper and lower regions of the cloud. The width of cloud anvil is shown to grow proportionally slower than the width of the rest of the cloud.
Atmos. Chem. Phys. Discuss., 15, 15977-16017, doi:10.5194/acpd-15-15977-2015, 2015
LSA SAF Meteosat FRP Products: Part 2 – Evaluation and demonstration of use in the Copernicus Atmosphere Monitoring Service (CAMS)
Atmos. Chem. Phys. Discuss., 15, 15909-15976, doi:10.5194/acpd-15-15909-2015, 2015
Meteosat SEVIRI Fire Radiative Power (FRP) products from the Land Surface Analysis Satellite Applications Facility (LSA SAF) – Part 1: Algorithms, product contents and analysis
Summary: Wildfires and prescribed burns strongly influence atmospheric chemistry, composition and climate. Characterising such fires at very high temporal resolution is best achieved using thermal observations of actively burning fires made from geostationary Earth observation satellites. This paper describes and evaluates the Fire Radiative Power (FRP) products generated by the Land Surface Analysis Satellite Applications Facility (LSA SAF) from data collected by the Meteosat geostationary satellites.
Atmos. Chem. Phys. Discuss., 15, 15831-15907, doi:10.5194/acpd-15-15831-2015, 2015
16 year climatology of cirrus clouds over a tropical station in southern India using ground and space-based lidar observations
Summary: We present the longest (1998 to 2013) cirrus cloud climatology over a tropical station using a ground based lidar. A statistically significant increase is found in the altitude of sub-visible cirrus clouds. Also a systematic shift from thin to sub-visible cirrus cloud type is observed. Ground-based lidar is found to detect more number of sub-visible cirrus clouds than space-based lidar. These findings have implications to global warming and stratosphere-troposphere water vapour exchange studies.
Atmos. Chem. Phys. Discuss., 15, 15791-15830, doi:10.5194/acpd-15-15791-2015, 2015
Improving aerosol interaction with clouds and precipitation in a regional chemical weather modeling system
Summary: A comprehensive aerosol-cloud-precipitation interaction (ACI) scheme has been developed under CMA chemical weather modeling system GRAPES/CUACE. The ACI for January 2013 has been studied under this model. The interactive micro-physical properties of clouds improve the precipitation, showing 24% to 48% enhancements of TS scoring for 6-h precipitation in all regions and reduction of the regional mean bias of temperature by 3 °C in certain precipitation events.
Atmos. Chem. Phys. Discuss., 15, 15755-15790, doi:10.5194/acpd-15-15755-2015, 2015
Post bubble-closeoff fractionation of gases in polar firn and ice cores: effects of accumulation rate on permeation through overloading pressure
Atmos. Chem. Phys. Discuss., 15, 15711-15753, doi:10.5194/acpd-15-15711-2015, 2015
The regional distribution characteristics of aerosol optical depth over the Tibetan Plateau
Summary: Different monthly variation patterns of aerosol optical depth are observed over the southern and northern Tibetan Plateau (TP). A natural boundary seems to extend to an altitude of 6–8 km, acting as a dividing line of higher dust occurrence in the northern TP and lower dust occurrence in the southern TP. The seasonal variations and spatial distribution patterns are closely related to high altitude terrain and atmospheric circulation.
Atmos. Chem. Phys. Discuss., 15, 15683-15710, doi:10.5194/acpd-15-15683-2015, 2015
Natural new particle formation at the coastal Antarctic site Neumayer
Summary: We measured condensation particle (CP) concentrations and particle size distributions at the coastal Antarctic station Neumayer. Several nucleation events were observed, but particles did not grow up to sizes required for acting as cloud condensation nuclei. A simple estimation indicated that apart from sulfuric acid, the derived growth rates required other low volatile precursor vapours.
Atmos. Chem. Phys. Discuss., 15, 15655-15681, doi:10.5194/acpd-15-15655-2015, 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 the average, 24% of all particles contain rBC and the observed rBC cores are always thickly coated.
Atmos. Chem. Phys. Discuss., 15, 15621-15654, doi:10.5194/acpd-15-15621-2015, 2015
Consistent response of Indian summer monsoon to Middle East dust in observations and simulations
Summary: Satellite data shows that the ISM rainfall in coastal southwest India, central and northern India, and Pakistan are 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, which are associated with the development of an anomalous low pressure system over the Arabian Sea due to dust-induced atmospheric heating.
Atmos. Chem. Phys. Discuss., 15, 15571-15619, doi:10.5194/acpd-15-15571-2015, 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. Discuss., 15, 15543-15570, doi:10.5194/acpd-15-15543-2015, 2015
Relating the hygroscopic properties of submicron aerosol to both gas- and particle-phase chemical composition in a boreal forest environment
Atmos. Chem. Phys. Discuss., 15, 15511-15541, doi:10.5194/acpd-15-15511-2015, 2015
Chemical and physical influences on aerosol activation in liquid clouds: an empirical study based on observations from the Jungfraujoch, Switzerland
Atmos. Chem. Phys. Discuss., 15, 15469-15510, doi:10.5194/acpd-15-15469-2015, 2015
Stable carbon isotope ratios of ambient secondary organic aerosols in Toronto
Atmos. Chem. Phys. Discuss., 15, 15431-15467, doi:10.5194/acpd-15-15431-2015, 2015
Annual evapotranspiration retrieved solely from satellites' vegetation indices for the Eastern Mediterranean
Atmos. Chem. Phys. Discuss., 15, 15397-15429, doi:10.5194/acpd-15-15397-2015, 2015
Black carbon, particle number concentration and nitrogen oxide emission factors of random in-use vehicles measured with the on-road chasing method
Atmos. Chem. Phys. Discuss., 15, 15355-15396, doi:10.5194/acpd-15-15355-2015, 2015
Spatial and temporal variations of the concentrations of PM10, PM2.5 and PM1 in China
Summary: Concentrations of PM10, PM2.5 and PM1 were monitored at 24 stations of CAWNET from 2006 to 2014. The average level of PM concentrations and relationships were investigated. Seasonal, interannual, diurnal variations of the PM were revealed. The meteorological factors effects on the PM were discussed. The highest particulate matter (PM) concentrations were observed at the stations of Xian, Zhengzhou and Gucheng, in Guanzhong and the Hua Bei Plain (HBP).
Atmos. Chem. Phys. Discuss., 15, 15319-15354, doi:10.5194/acpd-15-15319-2015, 2015
Neutral atmosphere temperature change at 90 km, 70° N, 19° E, 2003–2014
Atmos. Chem. Phys. Discuss., 15, 15289-15317, doi:10.5194/acpd-15-15289-2015, 2015
Investigation of particle and vapor wall-loss effects on controlled wood-smoke smog-chamber experiments
Summary: Losses of semi-volatile vapors to Teflon walls may contribute to significant primary particle evaporation during wood-smoke aerosol experiments. These vapor losses may also affect secondary organic aerosol formation during these experiments.
Atmos. Chem. Phys. Discuss., 15, 15243-15288, doi:10.5194/acpd-15-15243-2015, 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 0.22 K for the decade 2041-2050) and precipitation.
Atmos. Chem. Phys. Discuss., 15, 15155-15241, doi:10.5194/acpd-15-15155-2015, 2015
Transport pathways of peroxyacetyl nitrate in the upper troposphere and lower stratosphere from different monsoon systems during the summer monsoon season
Atmos. Chem. Phys. Discuss., 15, 15087-15135, doi:10.5194/acpd-15-15087-2015, 2015
A synthesis of cloud condensation nuclei counter (CCNC) measurements within the EUCAARI network
Summary: The research paper presents the first comprehensive overview of field measurements with the CCN Counter performed at a large number of locations around the world within the EUCAARI framework. The paper sheds light on the CCN number concentrations and activated fractions around the world and their dependence on the water vapour supersaturation ratio, the dependence of aerosol hygroscopicity on particle size, and seasonal and diurnal variation of CCN activation and hygroscopic properties.
Atmos. Chem. Phys. Discuss., 15, 15039-15086, doi:10.5194/acpd-15-15039-2015, 2015
Modeling study on the transport of summer dust and anthropogenic aerosols over the Tibetan Plateau
Summary: We firstly evaluated the Spectral Radiation-Transport Model for Aerosol Species combined with a non-hydrostatic regional model through comparing the simulation results and satellite observations, both in horizontal and vertical. The dust and anthropogenic aerosols in summer over the Tibetan Plateau are evaluated, and their distributions over the TP are presented. The transport of these aerosols over the Tibetan Plateau is also explored via combining the simulation results and reanalysis data.
Atmos. Chem. Phys. Discuss., 15, 15005-15037, doi:10.5194/acpd-15-15005-2015, 2015
Reassessment of MIPAS age of air trends and variability
Summary: Stratospheric circulation is thought to change as a consequence of climate change. Empirical evidence, however, is sparse. In this paper we present latitude- and altitude-resolved trends of the mean age of stratospheric air as derived from SF6 measurements performed by the MIPAS satellite instrument. The mean of the age of stratospheric air is a measure of the intensity of the Brewer-Dobson circulation. In this paper we discuss differences with respect to a preceding analysis by Stiller et al.
Atmos. Chem. Phys. Discuss., 15, 14685-14732, doi:10.5194/acpd-15-14685-2015, 2015
Sources of long-lived atmospheric VOCs at the rural boreal forest site, SMEAR II
Summary: In this study main source areas for long-lived VOCs at the boreal forest in SMEAR II were determined. Air masses arriving from eastern and western directions were more polluted than those arriving from northern direction. Biogenic and anthropogenic influence of in three different source profiles were determined. The elevated trace gas concentrations from forest fire episodes were observed clearly in the trajectory analysis.
Atmos. Chem. Phys. Discuss., 15, 14593-14641, doi:10.5194/acpd-15-14593-2015, 2015
Simultaneous monitoring of stable oxygen isotope composition in water vapour and precipitation over the central Tibetan Plateau
Atmos. Chem. Phys. Discuss., 15, 14445-14472, doi:10.5194/acpd-15-14445-2015, 2015
On the potential of ICOS atmospheric CO2 measurement network for the estimation of the biogenic CO2 budget of Europe
Summary: We study the potential of the European Integrated Carbon Observing System (ICOS) atmospheric network for estimating European CO2 ecosystem fluxes. Regional atmospheric inversions with synthetic data are used to derive it in terms of statistical uncertainty. This potential is high in Western Europe and future extensions of the network will increase it in Eastern Europe. Future improvements of the models underlying the inversion should also significantly decrease uncertainties at high resolution.
Atmos. Chem. Phys. Discuss., 15, 14221-14273, doi:10.5194/acpd-15-14221-2015, 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. Discuss., 15, 13657-13703, doi:10.5194/acpd-15-13657-2015, 2015
Remote sensing of soot carbon – Part 1: Distinguishing different absorbing aerosol species
Atmos. Chem. Phys. Discuss., 15, 13607-13656, doi:10.5194/acpd-15-13607-2015, 2015
Composition, size distribution, optical properties and radiative effects of re-suspended local mineral dust of Rome area by individual-particle microanalysis and radiative transfer modelling
Summary: New information is given here on mineralogy, microphysical and optical properties, and radiative effects, of PM10 types from surface rocks at a non-desert site (Rome area, Italy). A large data set was built, by SEM XEDS microanalysis, of mineral particles (silicates, quartz and calcite, depending on rocks). Dust types show different size distribution, optical properties, and radiative effects. Radiative transfer modelling (6SV) based on SEM XEDS data is a further original feature of this work.
Atmos. Chem. Phys. Discuss., 15, 13347-13393, doi:10.5194/acpd-15-13347-2015, 2015
Trends in concentrations of atmospheric gaseous and particulate species in rural eastern Tennessee as related to primary emissions reductions
Atmos. Chem. Phys. Discuss., 15, 13211-13262, doi:10.5194/acpd-15-13211-2015, 2015
Vertical variations of aerosols and the effects responded to the emission control: application of lidar ceilometer in Beijing during APEC, 2014
Summary: The manuscript is the first paper to validate and discuss the high resolution vertical profiles of aerosols using Ceilometer in Beijing, China. We introduce the contribution to aerosols during the different air pollution episode in Beijing. Also, we seize the opportunity of emission reduction during APEC to study the contribution to aerosols. The results are helpful to provide guidance of redefining coordinated emission control strategies to control the regional pollution over Northern China.
Atmos. Chem. Phys. Discuss., 15, 13173-13209, doi:10.5194/acpd-15-13173-2015, 2015
Observations of new particle formation in enhanced UV irradiance zones near cumulus clouds
Summary: During the CARRIBA-campaign on Barbados 91 cases with increased aerosol particle number concentrations near clouds were detected from helicopter-borne measurements. Most of these cases are correlated with enhanced irradiance in the ultraviolet range. The events have a mean length of 100m corresponding to a lifetime of 300s, meaning a growth of several nm/h. Such high values cannot be explained by sulfuric acid alone thus probably extremely low volatile organic compounds are involved here.
Atmos. Chem. Phys. Discuss., 15, 12423-12452, doi:10.5194/acpd-15-12423-2015, 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
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
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
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
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