LSA SAF Meteosat FRP products – Part 2: Evaluation and demonstration for use in the Copernicus Atmosphere Monitoring Service (CAMS)
Summary: Characterising the dynamics of wildfires at high temporal resolution is best achieved using observations from geostationary satellite sensors. The SEVIRI Fire Radiative Power (FRP) products have been developed using such imagery at up to 15-minute temporal frequency. These data are used to estimate wildfire fuel consumption and to the characterise smoke emissions from the 2007 Peloponnese "mega fires" within an atmospheric transport model.
Atmos. Chem. Phys., 15, 13241-13267, doi:10.5194/acp-15-13241-2015, 2015
LSA SAF Meteosat FRP products – Part 1: Algorithms, product contents, and analysis
Summary: Landscape fires strongly influence atmospheric chemistry, composition, and climate. Characterizing such fires at very high temporal resolution is best achieved using thermal observations of actively burning fires made from geostationary Earth Observation satellites. Here we detail 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., 15, 13217-13239, doi:10.5194/acp-15-13217-2015, 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 adequately simulates surface solar radiation (SSR) over Europe but significantly over/underestimates 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 conflicting 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., 15, 13195-13216, doi:10.5194/acp-15-13195-2015, 2015
Composition, size distribution, optical properties, and radiative effects of laboratory-resuspended PM10 from geological dust of the Rome area, by electron microscopy 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., 15, 13177-13194, doi:10.5194/acp-15-13177-2015, 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., 15, 13161-13176, doi:10.5194/acp-15-13161-2015, 2015
A potential vorticity-based determination of the transport barrier in the Asian summer monsoon anticyclone
Summary: The Asian summer monsoon provides an important pathway of tropospheric source gases and pollution into the lower stratosphere. This transport is characterized by deep convection and steady upwelling, combined with confinement inside a large-scale anticyclonic circulation in the upper troposphere and lower stratosphere. In this paper, we show that a barrier to horizontal transport in the monsoon can be determined from a local maximum in the gradient of potential vorticity.
Atmos. Chem. Phys., 15, 13145-13159, doi:10.5194/acp-15-13145-2015, 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 (r2=0.66, rRMSE=18.3%) 3. Population-weighted GOCI-derived PM2.5 over eastern China for 2013 is 53.8 μg/m3, threatening the health of its more than 400 million residents 4. Secondary inorganics (SO42-, NO3-, NH4+) & organic matter are the most significant components of GOCI-derived PM2.5.
Atmos. Chem. Phys., 15, 13133-13144, doi:10.5194/acp-15-13133-2015, 2015
The regime of aerosol asymmetry parameter over Europe, the Mediterranean and the Middle East based on MODIS satellite data: evaluation against surface AERONET measurements
Atmos. Chem. Phys., 15, 13113-13132, doi:10.5194/acp-15-13113-2015, 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 pointed out are discussed together with possible consequences on the middle atmospheric dynamics and transport.
Atmos. Chem. Phys., 15, 13097-13112, doi:10.5194/acp-15-13097-2015, 2015
Introduction: The Pan-Eurasian Experiment (PEEX) – multidisciplinary, multiscale and multicomponent research and capacity-building initiative
Summary: The Pan-European Experiment (PEEX) is introduced. PEEX is a multidisciplinary, multiscale and multicomponent research, research infrastructure and capacity-building program. This paper outlines the mission, vision and objectives of PEEX and introduces its main components, including the research agenda, research infrastructure, knowledge transfer and potential impacts on society. The paper also summarizes the main scientific questions that PEEX is going to tackle in the future.
Atmos. Chem. Phys., 15, 13085-13096, doi:10.5194/acp-15-13085-2015, 2015
Some insights into the condensing vapors driving new particle growth to CCN sizes on the basis of hygroscopicity measurements
Atmos. Chem. Phys., 15, 13071-13083, doi:10.5194/acp-15-13071-2015, 2015
Black carbon aerosol in winter northeastern Qinghai–Tibetan Plateau, China: the source, mixing state and optical property
Summary: An intensive campaign was conducted at the Qinghai-Tibetan Plateau using a ground-based single particle soot photometer and a photoacoustic extinctiometer. Significant enhancements of rBC loadings and number fraction of coated rBC were observed during the pollution episode. Biomass burning from N. India is determined to be an important potential source influencing the northeastern Qinghai-Tibetan Plateau. The rBC mixing state is important in determining absorption during the pollution episode.
Atmos. Chem. Phys., 15, 13059-13069, doi:10.5194/acp-15-13059-2015, 2015
Signature of tropical fires in the diurnal cycle of tropospheric CO as seen from Metop-A/IASI
Summary: Based on 5 years of CO columns derived from the IASI sounder, we show that tropospheric CO displays a diurnal signal with a seasonality and intensity that agrees well with the evolution of fires. We suggest that at night, after the passing of IASI at 21:30, a large amount of CO emissions from the smoldering phase is trapped in the boundary layer before being uplifted the next morning by natural and pyroconvection up to the free troposphere.
Atmos. Chem. Phys., 15, 13041-13057, doi:10.5194/acp-15-13041-2015, 2015
Does GOSAT capture the true seasonal cycle of carbon dioxide?
Summary: Atmospheric carbon dioxide concentration varies seasonally mainly due to plant photosynthesis in the Northern Hemisphere. We found that the satellite GOSAT can capture this variability from space to within 1ppm. We also found that models can differ by more than 1ppm. This implies that the satellite measurements could be useful in evaluating models and their prior estimates of carbon dioxide sources and sinks.
Atmos. Chem. Phys., 15, 13023-13040, doi:10.5194/acp-15-13023-2015, 2015
Isotopic signatures of production and uptake of H2 by soil
Summary: We investigated soil production and uptake of H2 and associated isotope effects. Uptake and emission of H2 occurred simultaneously at all sampling sites, with strongest emission where N2 fixing legume was present. The fractionation constant during soil uptake was about 0.945 and it did not show positive correlation with deposition velocity. The isotopic composition of H2 emitted from soil with legume was about -530‰, which is less deuterium-depleted than isotope equilibrium between H2O and H2.
Atmos. Chem. Phys., 15, 13003-13021, doi:10.5194/acp-15-13003-2015, 2015
Impact of gas-to-particle partitioning approaches on the simulated radiative effects of biogenic secondary organic aerosol
Summary: To understand the radiative effects of biogenic secondary organic aerosol (SOA) it is necessary to consider the manner in which it is distributed across the existing aerosol size distribution. We explore the importance of the approach taken by global-scale models to do this, when calculating the direct radiative effect (DRE) & first aerosol indirect effect (AIE) due to biogenic SOA. This choice has little effect on the DRE, but a substantial impact on the magnitude and even sign of the first AIE
Atmos. Chem. Phys., 15, 12989-13001, doi:10.5194/acp-15-12989-2015, 2015
Instantaneous longwave radiative impact of ozone: an application on IASI/MetOp observations
Atmos. Chem. Phys., 15, 12971-12987, doi:10.5194/acp-15-12971-2015, 2015
The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch
Summary: The paper explores the microphysical structure of clouds at the 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., 15, 12953-12969, doi:10.5194/acp-15-12953-2015, 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., 15, 12935-12952, doi:10.5194/acp-15-12935-2015, 2015
Feedbacks of dust and boundary layer meteorology during a dust storm in the eastern Mediterranean
Summary: In this paper we report on the feedbacks between dust and boundary layer meteorology during a dust storm over Egypt and Libya in April 2012, using an atmospheric composition forecasting system. Dust was found to act on atmospheric stability, leading to an increase (night) or a decrease (day) in dust production. Horizontal gradients of temperature were modified by the radiative impact of the dust layer, leading to changes in wind patterns at the edge of the storm due to the thermal wind effect.
Atmos. Chem. Phys., 15, 12909-12933, doi:10.5194/acp-15-12909-2015, 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: a mix of elongated and flattened cylindrical ice particles consistent with measurements. Comparison is best if flattened particles form a majority, with mean axis ratio around 2.8. NLCs from cylindrical particles are slightly brighter and consist of fewer but larger ice particle.
Atmos. Chem. Phys., 15, 12897-12907, doi:10.5194/acp-15-12897-2015, 2015
Characteristics and sources of submicron aerosols above the urban canopy (260 m) in Beijing, China, during the 2014 APEC summit
Summary: A comprehensive characterization of submicron aerosol composition and sources at 260m in urban Beijing during APEC 2014 is presented. Aerosol species were shown to decrease substantially by 40–80% during APEC, whereas the bulk composition was relatively similar to the result of synergetic controls of secondary precursors. Our results elucidated that the good air quality during APEC was the combined result of emission controls and meteorological effects, with the former playing the dominant role.
Atmos. Chem. Phys., 15, 12879-12895, doi:10.5194/acp-15-12879-2015, 2015
Laboratory evidence of organic peroxide and peroxyhemiacetal formation in the aqueous phase and implications for aqueous OH
Summary: This paper demonstrates organic peroxide and peroxyhemiacetal 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., 15, 12867-12877, doi:10.5194/acp-15-12867-2015, 2015
A process-based 222radon 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., 15, 12845-12865, doi:10.5194/acp-15-12845-2015, 2015
Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes
Summary: We implement new diurnal variation scheme for ammonia livestock emissions and bidirectional exchange scheme and its adjoint in the GEOS-Chem global chemical transport model. Updated diurnal variability improves modeled-to-hourly in situ measurements comparison. The ammonium soil pool in the bidirectional exchange model largely extends the ammonia lifetime in the atmosphere. Large model biases remain as livestock emissions are still underestimated.
Atmos. Chem. Phys., 15, 12823-12843, doi:10.5194/acp-15-12823-2015, 2015
Quantifying sources of black carbon in western North America using observationally based analysis and an emission tagging technique in the Community Atmosphere Model
Summary: We use a global climate model with an explicit source tagging technique to quantify contributions of emissions from various geographical regions and sectors to BC in North America. Model results are evaluated against measurements of near-surface and in-snow BC. We found strong spatial variations of BC and its radiative forcing that can be quantitatively attributed to the various source origins, and also identified a significant source of BC in snow that is likely missing in most climate models.
Atmos. Chem. Phys., 15, 12805-12822, doi:10.5194/acp-15-12805-2015, 2015
Retrieval of ammonia from ground-based FTIR solar spectra
Summary: We present a new retrieval method for ammonia (NH3) concentrations and total columns from ground-based Fourier transform infrared (FTIR) observations. Observations from Bremen, Lauder, Réunion and Jungfraujoch are used to show the capabilities of the new retrieval. The developed retrieval provides a new way of obtaining time-resolved measurements and will be useful for understanding the dynamics of ammonia concentrations in the atmosphere and for satellite and model validation.
Atmos. Chem. Phys., 15, 12789-12803, doi:10.5194/acp-15-12789-2015, 2015
On the potential of the ICOS atmospheric CO2 measurement network for estimating 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., 15, 12765-12787, doi:10.5194/acp-15-12765-2015, 2015
New particle-dependent parameterizations of heterogeneous freezing processes: sensitivity studies of convective clouds with an air parcel model
Summary: In mid-latitudes, the major fraction of precipitation is initiated via the ice phase. Cloud model simulations estimated the role of aerosol particle types and heterogeneous freezing modes on the ice phase. The results show that the formation of mixed-phase and ice clouds is promoted by the immersion freezing mode, broad drop size spectra containing small as well as large drops, insoluble particles composed by bacteria, feldspar, and illite, and temperatures below -25°C.
Atmos. Chem. Phys., 15, 12741-12763, doi:10.5194/acp-15-12741-2015, 2015
Direct radiative effect by brown carbon over the Indo-Gangetic Plain
Summary: There have been relatively few measurement-based estimates for the direct radiative effect of brown carbon so far. This is first time that the direct radiative effect of brown carbon is estimated by exploiting the AERONET-retrieved imaginary indices. We estimated it for four sites in the Indo-Gangetic Plain: Karachi, Lahore, Kanpur and Gandhi College.
Atmos. Chem. Phys., 15, 12731-12740, doi:10.5194/acp-15-12731-2015, 2015
Estimation of continuous anthropogenic CO2: model-based evaluation of CO2, CO, δ13C(CO2) and Δ14C(CO2) tracer methods
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 modeling.
Atmos. Chem. Phys., 15, 12705-12729, doi:10.5194/acp-15-12705-2015, 2015
Radiative forcing and climate response to projected 21st century aerosol decreases
Summary: Decreases in aerosols over the 21st century as projected by the Representative Concentration Pathways (RCPs) lead to increases up to 0.5 - 1 ºC in global temperature and up to 0.05 - 0.1 mm/day in global precipitation, depending strongly on present-day aerosol radiative forcing. In East Asia, future aerosol decreases could be responsible for 10-20% of the total temperature increase (30-40% with strong present-day aerosol forcing), even under the high greenhouse gas emissions scenario (RCP8.5).
Atmos. Chem. Phys., 15, 12681-12703, doi:10.5194/acp-15-12681-2015, 2015
Impact of emission controls on air quality in Beijing during APEC 2014: lidar ceilometer observations
Summary: The manuscript is the first paper to validate and discuss the high-resolution vertical profiles of aerosols using a ceilometer in Beijing, China. We introduce the contribution of aerosols during different air pollution episodes in Beijing. Also, we seize the opportunity of emission reduction during APEC to study the contribution of aerosols. The results are helpful to provide guidance in redefining coordinated emission control strategies to control the regional pollution over northern China.
Atmos. Chem. Phys., 15, 12667-12680, doi:10.5194/acp-15-12667-2015, 2015
The effects of global change upon United States air quality
Atmos. Chem. Phys., 15, 12645-12665, doi:10.5194/acp-15-12645-2015, 2015
Advantages of a 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 on-site surveys. 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., 15, 12623-12644, doi:10.5194/acp-15-12623-2015, 2015
Variations of surface ozone at Ieodo Ocean Research Station in the East China Sea and the influence of Asian outflows
Summary: In east Asia, emissions of O3 precursors have gradually increased and O3 concentrations 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 their continental influence on the regional background concentrations of O3.
Atmos. Chem. Phys., 15, 12611-12621, doi:10.5194/acp-15-12611-2015, 2015
Toward enhanced capability for detecting and predicting dust events in the western United States: the Arizona case study
Summary: We developed Arizona dust records in 2005-2013 using multiple surface and remote sensing observation data sets. The inter-annual variability of dust events was anticorrelated with three drought indicators (PDSI, satellite NDVI and soil moisture), and stronger dust activity was found in the afternoon than in the morning due to stronger winds and drier soil. Impact of a recent dust event accompanied by a stratospheric ozone intrusion was evaluated with various observational and modeling data sets.
Atmos. Chem. Phys., 15, 12595-12610, doi:10.5194/acp-15-12595-2015, 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., 15, 12581-12594, doi:10.5194/acp-15-12581-2015, 2015
Annual evapotranspiration retrieved from satellite vegetation indices for the eastern Mediterranean at 250 m spatial resolution
Summary: We present an empirical method to retrieve actual evapotranspiration (ET) at a spatial resolution of 250m for the eastern Mediterranean based on observed relationships between satellite vegetation indices and eddy covariance ET. Our model was successfully evaluated against two physically based models and calculated ET from water catchment balances along rainfall gradient. In the absence of high-resolution models, our model is expected to contribute to the ecohydrological study of this region.
Atmos. Chem. Phys., 15, 12567-12579, doi:10.5194/acp-15-12567-2015, 2015
Ice nucleating particles at a coastal marine boundary layer site: correlations with aerosol type and meteorological conditions
Atmos. Chem. Phys., 15, 12547-12566, doi:10.5194/acp-15-12547-2015, 2015
Diurnal, seasonal and long-term variations of global formaldehyde columns inferred from combined OMI and GOME-2 observations
Summary: We present the new version of the BIRA-IASB algorithm for the retrieval of H2CO columns from OMI and GOME-2A and B measurements. Validation results at seven stations in Europe, China and Africa confirm the capacity of the satellite measurements to resolve diurnal variations in H2CO columns. Furthermore, vertical profiles derived from MAX-DOAS measurements in Beijing and in Bujumbura are used for a more detailed validation exercise. Finally trends are estimated using 10 years of OMI observations.
Atmos. Chem. Phys., 15, 12519-12545, doi:10.5194/acp-15-12519-2015, 2015
A multi-year study of lower tropospheric aerosol variability and systematic relationships from four North American regions
Summary: Variability in aerosol optical properties relevant to radiative forcing were studied on several timescales at four continental North American NOAA-ESRL sites. Light scattering and intensive properties varied most on seasonal scales while absorption variability on weekly and diurnal timescales was comparable to its seasonal variability. Large reductions in light scattering were observed at the two long-term sites (relative to late 1990s), along with a smaller contribution by sub-1µm particles.
Atmos. Chem. Phys., 15, 12487-12517, doi:10.5194/acp-15-12487-2015, 2015
Comparison of the CMAM30 data set with ACE-FTS and OSIRIS: polar regions
Summary: The CMAM30 data set takes a chemistry-climate model and relaxes the dynamics to reanalysis, which can then provide chemistry fields not available from the reanalysis data set. This paper addresses this gap by comparing temperature, water vapour, ozone and methane to satellite data to determine and document any biases in the model fields. The lack of ozone destruction and dehydration in the SH polar vortex is shown to be due to the treatment of polar stratosphere clouds in the model.
Atmos. Chem. Phys., 15, 12465-12485, doi:10.5194/acp-15-12465-2015, 2015
Aerosol size distribution and new particle formation in the western Yangtze River Delta of China: 2 years of measurements at the SORPES station
Summary: We report 2 years of measurements of submicron particles at the SORPES station and provide a comprehensive understanding of main factors controlling temporal variation of the aerosol size distribution and NPF in eastern China. The number concentrations of total particles at Nanjing were comparable to other Chinese megacities but the frequency of NPF was much higher. Year-to-year differences of meteorological conditions could significantly influence the seasonal cycle of NPF and growth.
Atmos. Chem. Phys., 15, 12445-12464, doi:10.5194/acp-15-12445-2015, 2015
On measurements of aerosol-gas composition of the atmosphere during two expeditions in 2013 along the Northern Sea Route
Summary: We discuss the spatiotemporal variations in aerosol characteristics, measured along the Northern Sea Route in RV Akademik Fedorov and RV Professor Khljustin cruises. The variability ranges of the average aerosol parameters in separate seas and regions were from 2.5 to 24cm-3 for number concentration of particles; from 830 to 2970ngm-3 for aerosol mass concentrations; from 20 to 150ngm-3 for black carbon mass concentrations; and from 0.03 to 0.19 for aerosol optical depth (0.5um).
Atmos. Chem. Phys., 15, 12413-12443, doi:10.5194/acp-15-12413-2015, 2015
Putting the clouds back in aerosol–cloud interactions
Summary: Aerosols affect cloud properties, and the radiative effects of clouds. Human emissions of aerosol particles and precursors may alter the radiative effects of clouds. This is generally a cooling effect that offsets other warming effects of human emissions of gases. Simulating these aerosol effects on clouds are highly dependent on the formulation of the microphysical (cloud droplet scale) processes. This work uses model simulations to show these effects are large, and depend on certain processes.
Atmos. Chem. Phys., 15, 12397-12411, doi:10.5194/acp-15-12397-2015, 2015
Technical note: New particle formation event forecasts during PEGASOS–Zeppelin Northern mission 2013 in Hyytiälä, Finland
Atmos. Chem. Phys., 15, 12385-12396, doi:10.5194/acp-15-12385-2015, 2015
Spatial and temporal variability of clouds and precipitation over Germany: multiscale simulations across the "gray zone"
Summary: This paper assesses the resolution dependance of clouds and precipitation over Germany by numerical simulations with the COnsortium for Small-scale MOdeling model for 7 cases of 2013. By means of a series of grid-refinement resolution tests, the variability of clouds and precipitation and how this variability changes with model resolution are investigated. The performance of the model at these resolutions is of general relevance to the research community as well as to operational forecasters
Atmos. Chem. Phys., 15, 12361-12384, doi:10.5194/acp-15-12361-2015, 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/bulk deposition fluxes (2.9-83.3kg N ha-1 yr-1) of inorganic Nr species ranked by land use as urban > rural > background sites and by regions as north China > southeast China > southwest China > northeast China > northwest China > Tibetan Plateau, reflecting the impact of anthropogenic Nr emission. Average dry and wet/bulk N deposition fluxes were 20.6 ± 11.2 and 19.3 ± 9.2kg kg N ha-1 yr-1 across China, respectively.
Atmos. Chem. Phys., 15, 12345-12360, doi:10.5194/acp-15-12345-2015, 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., 15, 12327-12344, doi:10.5194/acp-15-12327-2015, 2015
An algorithm for the numerical solution of the multivariate master equation for stochastic coalescence
Summary: The mathematical description of finite volume coalescing systems relies on the multivariate master equation. However, due to its complexity, it has analytical solutions only for a limited number of kernels and initial conditions. In this paper, in an effort to solve this problem, we have introduced a novel numerical approach to calculate the solution of the multivariate coalescence master equation that works for any type of kernel and initial conditions.
Atmos. Chem. Phys., 15, 12315-12326, doi:10.5194/acp-15-12315-2015, 2015
Modeling particle nucleation and growth over northern California during the 2010 CARES campaign
Atmos. Chem. Phys., 15, 12283-12313, doi:10.5194/acp-15-12283-2015, 2015
A qualitative comparison of secondary organic aerosol yields and composition from ozonolysis of monoterpenes at varying concentrations of NO2
Summary: The addition of NO2 to atmospheric particle formation simulations based on ozone reactions with tree-emitted monoterpenes results in changing particle composition and mass yields, with effects that vary across the range of studied monoterpenes. For alpha-pinene, a dominantly emitted terpene in the United States, NO2 addition suppresses particle formation, while for others, particle yields remain high.
Atmos. Chem. Phys., 15, 12267-12281, doi:10.5194/acp-15-12267-2015, 2015
Impacts of Amazonia biomass burning aerosols assessed from short-range weather forecasts
Atmos. Chem. Phys., 15, 12251-12266, doi:10.5194/acp-15-12251-2015, 2015
The radiative impact of desert dust on orographic rain in the Cévennes–Vivarais area: a case study from HyMeX
Summary: We analyze the direct radiative impact of an intense African dust plume on orographic precipitation in the western Mediterranean in the fall of 2012 using high-resolution simulations from a convection permitting mesoscale model validated against measurements acquired during the first special observation period of HyMeX. We show that the dust's direct radiative effect in such a dynamical environment is not sufficient to impact 24h of accumulated rainfall over the Cevennes in the dust simulation.
Atmos. Chem. Phys., 15, 12231-12249, doi:10.5194/acp-15-12231-2015, 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., 15, 12211-12229, doi:10.5194/acp-15-12211-2015, 2015
Assessment of long-term 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 though it tends to underestimate the AOD.
Atmos. Chem. Phys., 15, 12193-12209, doi:10.5194/acp-15-12193-2015, 2015
CALIOP near-real-time backscatter products compared to EARLINET data
Summary: The expedited near-real-time Level 1.5 Cloud-Aerosol Lidar with Orthogonal Polarization version 3 products were evaluated against data from the ground-based European Aerosol Research Lidar Network. The statistical framework and results of the 3-year evaluation of 48 CALIOP overpasses with ground tracks within a 100km distance from operating EARLINET stations are presented.
Atmos. Chem. Phys., 15, 12179-12191, doi:10.5194/acp-15-12179-2015, 2015
What is the real role of iron oxides in the optical properties of dust aerosols?
Summary: Three different continuous datasets for complex refractive indices of hematite are employed in climate models, the real role of iron-oxides in the optical properties of dust aerosols becomes a key scientific question, and we address this problem by considering different refractive indices, size distributions, and more logical weight fractions and mixing states of hematite. More laboratory measurements should be taken into account when assessing the effect of mineral dust on climate forcing.
Atmos. Chem. Phys., 15, 12159-12177, doi:10.5194/acp-15-12159-2015, 2015
Biotic stress accelerates formation of climate-relevant aerosols in boreal forests
Summary: Global warming will induce large-scale insect outbreaks in boreal forests. Our results from field and laboratory experiments, satellite observations and global-scale modelling suggest that more frequent insect outbreaks, in addition to temperature-dependent increases in VOC emissions, could result in substantial increases in biogenic SOA formation and therefore affect both aerosol direct and indirect forcing of climate at regional scales. This should be considered in future climate predictions.
Atmos. Chem. Phys., 15, 12139-12157, doi:10.5194/acp-15-12139-2015, 2015
Impact of atmospheric circulations on aerosol distributions in autumn over eastern China: observational evidence
Summary: We systematically examined that how various large-scale atmospheric conditions (ACs) affects the distributions of aerosol optical depth (AOD) over eastern China. We extract and depict nine main types for AOD (six polluted types and three clean types) in autumn over eastern China. The results provide convincing evidence that the general characteristics of atmospheric circulations contribute significantly to the different types of regional pollution.
Atmos. Chem. Phys., 15, 12115-12138, doi:10.5194/acp-15-12115-2015, 2015