Sulfur dioxide (SO2) from MIPAS in the upper troposphere and lower stratosphere 2002–2012
M. Höpfner, C. D. Boone, B. Funke, N. Glatthor, U. Grabowski, A. Günther, S. Kellmann, M. Kiefer, A. Linden, S. Lossow, H. C. Pumphrey, W. G. Read, A. Roiger, G. Stiller, H. Schlager, T. von Clarmann, and K. Wissmüller Atmos. Chem. Phys. Discuss., 15, 5801-5847, 2015 AbstractDiscussion Paper (PDF, 2757 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
27 Feb 2015
Dust aerosol and optical properties over North Africa simulated with the ALADIN numerical prediction model from 2006 to 2010
Summary: This manuscript focuses on the elaboration and interpretation of a dust aerosol climatology for North Africa using an operational numerical weather prediction model. The use of an NWP model for this type of study is new and allows to better represent the coupled processes between the surface and the atmosphere and mesoscales process. The aim of these simulations is to quantify the dust emission and deposition, locate the major areas of dust emission and establish a climatology of aerosol optical
Heterogeneous reaction of peroxyacetic acid and hydrogen peroxide on ambient aerosol particles under dry and humid conditions: kinetics, mechanism and implications
Summary: The present study provides the first measurement for the uptake coefficient of gaseous peroxide compounds including peroxyacetic acid and hydrogen peroxide on the ambient particles (PM2.5 and Asian Storm Dust) over a wide range of relative humidity. The measured uptake coefficient values suggest that the heterogeneous reaction on the ambient particles plays an important role in the atmospheric budgets of peroxide compounds and potentially affects the components of aerosols in the atmosphere.
Ultrafine particle sources and in-situ formation in a European megacity
M. Pikridas, J. Sciare, F. Freutel, S. Crumeyrolle, S.-L. von der Weiden-Reinmüller, A. Borbon, A. Schwarzenboeck, M. Merkel, M. Crippa, E. Kostenidou, M. Psichoudaki, L. Hildebrandt, G. J. Engelhart, T. Petäjä, A. S. H. Prévôt, F. Drewnick, U. Baltensperger, A. Wiedensohler, M. Kulmala, M. Beekmann, and S. N. Pandis Atmos. Chem. Phys. Discuss., 15, 5663-5712, 2015 AbstractDiscussion Paper (PDF, 4433 KB)Supplement (2047 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACPSpecial Issue
26 Feb 2015
What's the real role of iron-oxides in the optical properties of dust aerosols?
Summary: Three different continuous datasets for complex refractive indices of hematite are employed in climate models, the real role of iron-oxides in the optical properties of dust aerosols becomes a key scientific question, and we address this problem by considering different refractive indices, size distributions, and more logical weight fractions and mixing states of hematite.More laboratory measurements should be taken into account when assessing the effect of mineral dust on climate forcing.
The importance of interstitial particle scavenging by cloud droplets in shaping the remote aerosol size distribution and global aerosol-climate effects
Summary: In this paper we show that coagulation of cloud droplets with interstitial aerosol particles, a process often neglecting in atmospheric aerosol models, has a significant impact on aerosol size distributions and radiative forcings.
J. R. Pierce, B. Croft, J. K. Kodros, S. D. D'Andrea, and R. V. Martin Atmos. Chem. Phys. Discuss., 15, 5589-5618, 2015 AbstractDiscussion Paper (PDF, 892 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
26 Feb 2015
On the reversibility of transitions between closed and open cellular convection
Summary: Most research on the relationship between aerosol and closed/open cell transitions tends to focus on the closed to open transition. Here we address the two-way transition between closed and open cellular states using a cloud resolving model. We find inherent asymmetry in the transitions and explain the source of the asymmetry. Results are supported by a dynamical system analogue to the full system.
Ocean mediation of tropospheric response to reflecting and absorbing aerosols
Summary: Strong solar heating by absorbing aerosols (black carbon) is considered more effective in inducing atmospheric circulation change than reflecting aerosols (sulfate), which do not have direct atmospheric heating effect. Surprisingly, we show that reflecting aerosols induce tropospheric temperature and circulation response similar to that induced by absorbing aerosols. The common response is mediated by the ocean through SST gradient, a process overlooked so far in aerosol-climate connection.
Partitioning and budget of inorganic and organic chlorine species observed by MIPAS-B and TELIS in the Arctic in March 2011
G. Wetzel, H. Oelhaf, M. Birk, A. de Lange, A. Engel, F. Friedl-Vallon, O. Kirner, A. Kleinert, G. Maucher, H. Nordmeyer, J. Orphal, R. Ruhnke, B.-M. Sinnhuber, and P. Vogt Atmos. Chem. Phys. Discuss., 15, 5391-5422, 2015 AbstractDiscussion Paper (PDF, 818 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
25 Feb 2015
Molecular composition of aged secondary organic aerosol generated from a mixture of biogenic volatile compounds using ultrahigh resolution mass spectrometry
I. Kourtchev, J.-F. Doussin, C. Giorio, B. Mahon, E. M. Wilson, N. Maurin, E. Pangui, D. S. Venables, J. C. Wenger, and M. Kalberer Atmos. Chem. Phys. Discuss., 15, 5359-5389, 2015 AbstractDiscussion Paper (PDF, 4107 KB)Supplement (405 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
25 Feb 2015
Regional data assimilation of multi-spectral MOPITT observations of CO over North America
Summary: We present a high-resolution (0.5x0.667) regional CO inversion over North America in the period of June 2004 – May 2005, using adjoint of GEOS-Chem model and MOPITT CO observations. With optimized lateral boundary conditions, we show that regional inversion analyses can reduce the sensitivity of the CO source estimates to errors in long-range transport and in the distributions of the hydroxyl radical (OH), and consequently, provide better quantification on regional CO source estimates.
Z. Jiang, D. B. A. Jones, J. Worden, H. M. Worden, D. K. Henze, and Y. Wang Atmos. Chem. Phys. Discuss., 15, 5327-5358, 2015 AbstractDiscussion Paper (PDF, 7162 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
25 Feb 2015
Top-down constraints on atmospheric mercury emissions and implications for global biogeochemical cycling
Summary: A better knowledge of mercury (Hg) emission fluxes into the global atmosphere is important for assessing its human health impacts and evaluating effectiveness of corresponding policy actions. We for the first time apply a top-down approach at global scale to quantitatively estimate present-day mercury emission sources as well as key parameters in a chemical transport model, in order to better constrain the global biogeochemical cycle of mercury.
S. Song, N. E. Selin, A. L. Soerensen, H. Angot, R. Artz, S. Brooks, E.-G. Brunke, G. Conley, A. Dommergue, R. Ebinghaus, T. M. Holsen, D. A. Jaffe, S. Kang, P. Kelley, W. T. Luke, O. Magand, K. Marumoto, K. A. Pfaffhuber, X. Ren, G.-R. Sheu, F. Slemr, T. Warneke, A. Weigelt, P. Weiss-Penzias, D. C. Wip, and Q. Zhang Atmos. Chem. Phys. Discuss., 15, 5269-5325, 2015 AbstractDiscussion Paper (PDF, 2875 KB)Supplement (1016 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
25 Feb 2015
Unusual stratospheric ozone anomalies observed in 22 years of measurements from Lauder, New Zealand
Summary: This paper highlights 2 unusual mid-stratospheric ozone anomalies in our 22 year ground-based dataset. One of these is a very large month long increase in June 2001 which we are able to associate with very unusually low equatorial air which persists over Lauder for much of June. The other ozone anomaly persists over about 4 years, and, using MLS data, we show that this is associated with unusually high N2O during this period. We show that this positive ozone and N2O anomaly over Lauder is tempor
G. E. Nedoluha, I. S. Boyd, A. Parrish, R. M. Gomez, D. R. Allen, L. Froidevaux, B. J. Connor, and R. R. Querel Atmos. Chem. Phys. Discuss., 15, 5241-5267, 2015 AbstractDiscussion Paper (PDF, 1225 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
24 Feb 2015
Middle East versus Saharan dust extinction-to-backscatter ratios
A. Nisantzi, R. E. Mamouri, A. Ansmann, G. L. Schuster, and D. G. Hadjimitsis Atmos. Chem. Phys. Discuss., 15, 5203-5240, 2015 AbstractDiscussion Paper (PDF, 2751 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
24 Feb 2015
Momentum forcing of the QBO by equatorial waves in recent reanalyses
Investigation of the adiabatic assumption for estimating cloud micro- and macrophysical properties from satellite and ground
Summary: We investigated the accuracy of quantities relevant for the first indirect aerosol effect, with focus on the cloud droplet number concentration (CDNC) and cloud geometrical depth (H). Therefore we compared differences from satellite and ground-based retrievals for 4 different cases and found the best match for a homogeneous case with relative mean difference of 15% in H and 27% in CDNC. We further evaluated cloud adiabacity and found subadiabatic behaviour consistent with previous studies.
Temporal variations of flux and altitude of sulfur dioxide emissions during volcanic eruptions: implications for long-range dispersal of volcanic clouds
Summary: 1-IASI spaceborne imagery is used to reconstruct temporal variations of flux and altitude of volcanic emissions via an inversion procedure.2-Ground-based UV measurements underestimate the SO2 flux by one order of magnitude, due to ash-induced plume opacity.3-Assimilation of SO2 altitude, retrieved directly from IASI, should render the inversion scheme independent of the wind shear prerequisite.4-CALIOP LiDAR observations support the coexistence of SO2 and sulfate aerosols in the volcanic cloud
M. Boichu, L. Clarisse, J.-C. Péré, H. Herbin, P. Goloub, F. Thieuleux, F. Ducos, C. Clerbaux, and D. Tanré Atmos. Chem. Phys. Discuss., 15, 5031-5077, 2015 AbstractDiscussion Paper (PDF, 8721 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
23 Feb 2015
Polar processing in a split vortex: early winter Arctic ozone loss in 2012/13
Summary: Sudden Stratospheric warmings (SSWs) cause a rapid rise in lower stratospheric temperatures, terminating conditions favorable to chemical ozone loss. We show that although temperatures rose precipitously during the vortex split SSW in early Jan 2013, because the offspring vortices each remained isolated and in regions that received sunlight, chemical ozone loss continued for over a month after the SSW. Dec/Jan Arctic ozone loss was larger than any previously observed during that period.
The impact of observing characteristics on the ability to predict ozone under varying polluted photochemical regimes
Summary: Using a simplified air quality forecasting model we explore how characteristicis of air quality observations affect our ability to understand and predict ozone air pollution. We show that the photochemical conditions can strongly influence the observing priorities for ozone prediction. Such as, which species are observed, how well, when, and how frequently. High freqency observations of ozone, NOx and HCHO in combination during the morning and afternoon are particularly advantageous.
Global evaluation of ammonia bi-directional exchange
L. Zhu, D. Henze, J. Bash, G.-R. Jeong, K. Cady-Pereira, M. Shephard, M. Luo, F. Paulot, and S. Capps Atmos. Chem. Phys. Discuss., 15, 4823-4877, 2015 AbstractDiscussion Paper (PDF, 8823 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
20 Feb 2015
Climate forced air-quality modeling at urban scale: sensitivity to model resolution, emissions and meteorology
Summary: The efficacy of emission policies is explored by coarse resolution modeling applications. These were shown to be biased, overestimating that efficacy indicated in simulations with refined resolution. In order to improve our assessments we need to quantify those biases. In this study we show that the ozone bias of the coarse run is reduced by 40% by adopting higher resolution emissions. For PM2.5 the coarse run cannot selectively incorporate local scale features in order to reduce model error.
Aircraft measurements of gravity waves in the upper troposphere and lower stratosphere during the START08 Field Experiment
Summary: Based on spectral and wavelet analyses, along with a diagnosis of the polarization relations, this study analyzes in-situ airborne measurements from the 2008 Stratosphere-Troposphere Analyses of Regional Transport (START08) experiment to characterize gravity waves in the extratropical upper troposphere and lower stratosphere (ExUTLS) region. The focus is on the second research flight (RF02), which was dedicated to probing gravity waves associated with strong upper-tropospheric jet-front systems.
Fuqing Zhang, Junhong Wei, Meng Zhang, K. P. Bowman, L. L. Pan, E. Atlas, and S. C. Wofsy Atmos. Chem. Phys. Discuss., 15, 4725-4766, 2015 AbstractDiscussion Paper (PDF, 8592 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
20 Feb 2015
In-situ single submicron particle composition analysis of ice residuals from mountain-top mixed-phase clouds in Central Europe
S. Schmidt, J. Schneider, T. Klimach, S. Mertes, L. P. Schenk, J. Curtius, P. Kupiszewski, E. Hammer, P. Vochezer, G. Lloyd, M. Ebert, K. Kandler, S. Weinbruch, and S. Borrmann Atmos. Chem. Phys. Discuss., 15, 4677-4724, 2015 AbstractDiscussion Paper (PDF, 5015 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACPSpecial Issue
19 Feb 2015
Mercury vapor air–surface exchange measured by collocated micrometeorological and enclosure methods – Part II: Bias and uncertainty analysis
A perturbed parameter model ensemble to investigate 1991 Mt Pinatubo's initial sulfur mass emission
Summary: Model results suggest that the initial mass loading of the 1991 Pinatubo eruption is approximately 14 Mt of SO2. The sulfur injection vertical distribution is strongly skewed towards the lower stratosphere, leading to a peak mass sulfur injection at 19-22 km.
J.-X. Sheng, D. K. Weisenstein, B.-P. Luo, E. Rozanov, F. Arfeuille, and T. Peter Atmos. Chem. Phys. Discuss., 15, 4601-4625, 2015 AbstractDiscussion Paper (PDF, 629 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
18 Feb 2015
A large and ubiquitous source of atmospheric formic acid
Summary: Formic acid (HCOOH) is an abundant atmospheric acid that affects precipitation chemistry and acidity. HCOOH measurements over the US are 2-3× larger than can be explained by known sources and sinks, revealing a key gap in current understanding. Observations indicate a large biogenic source plus chemical production across a range of precursors. Model simulations cannot capture the HCOOH diurnal amplitude or nocturnal profile, implying a deposition bias and possibly even larger missing source.
D. B. Millet, M. Baasandorj, D. K. Farmer, J. A. Thornton, K. Baumann, P. Brophy, S. Chaliyakunnel, J. A. de Gouw, M. Graus, L. Hu, A. Koss, B. H. Lee, F. D. Lopez-Hilfiker, J. A. Neuman, F. Paulot, J. Peischl, I. B. Pollack, T. B. Ryerson, C. Warneke, B. J. Williams, and J. Xu Atmos. Chem. Phys. Discuss., 15, 4537-4599, 2015 AbstractDiscussion Paper (PDF, 8498 KB)Supplement (832 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
18 Feb 2015
Estimating global and North American methane emissions with high spatial resolution using GOSAT satellite data
A. J. Turner, D. J. Jacob, K. J. Wecht, J. D. Maasakkers, S. C. Biraud, H. Boesch, K. W. Bowman, N. M. Deutscher, M. K. Dubey, D. W. T. Griffith, F. Hase, A. Kuze, J. Notholt, H. Ohyama, R. Parker, V. H. Payne, R. Sussmann, V. A. Velazco, T. Warneke, P. O. Wennberg, and D. Wunch Atmos. Chem. Phys. Discuss., 15, 4495-4536, 2015 AbstractDiscussion Paper (PDF, 8128 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
18 Feb 2015
Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds
Summary: We measured a large suite organic compounds using a recently developed Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a (HR-ToF-CIMS). The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We find that approximately 50% of the detected particle phase mass is associated with compounds having effective vapor pressures 4, or more, orders of magnitude lower than commonly measured products.
F. D. Lopez-Hilfiker, C. Mohr, M. Ehn, F. Rubach, E. Kleist, J. Wildt, Th. F. Mentel, A. Carrasquillo, K. Daumit, J. Hunter, J. H. Kroll, D. Worsnop, and J. A. Thornton Atmos. Chem. Phys. Discuss., 15, 4463-4494, 2015 AbstractDiscussion Paper (PDF, 570 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
18 Feb 2015
Ozone and NOx chemistry in the eastern US: evaluation of CMAQ/CB05 with satellite (OMI) data
T. P. Canty, L. Hembeck, T. P. Vinciguerra, D. C. Anderson, D. L. Goldberg, S. F. Carpenter, D. J. Allen, C. P. Loughner, R. J. Salawitch, and R. R. Dickerson Atmos. Chem. Phys. Discuss., 15, 4427-4461, 2015 AbstractDiscussion Paper (PDF, 5256 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
17 Feb 2015
Impact of the 2009 major stratospheric sudden warming on the composition of the stratosphere
Summary: A remarkable Major stratospheric sudden Warming (MW) during the boreal winter 2008/09 is studied with the Chemical Lagrangian Model of the Stratosphere (CLaMS). We investigate 1) how mixing triggered by this event correlates the wave forcing and 2) how transport and mixing affect the composition of the whole stratosphere in the northern hemisphere by using the tracer-tracer correlation technique.
M. Tao, P. Konopka, F. Ploeger, J.-U. Grooß, R. Müller, C. M. Volk, K. A. Walker, and M. Riese Atmos. Chem. Phys. Discuss., 15, 4383-4426, 2015 AbstractDiscussion Paper (PDF, 4056 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
17 Feb 2015
Global distributions of overlapping gravity waves in HIRDLS data
Summary: Data from the HIRDLS instrument are used to study the numerical variability of gravity waves. Observed distributions are dominated by long-vertical-short-horizontal-wavelength waves, with a similar spectral form at all locations. We further divide our data into subspecies by wavelength, and investigate variation of these subspecies in time and space. We show that the variations associated with particular phenomena arise due to changes in specific parts of the spectrum.
Data assimilation of satellite retrieved ozone, carbon monoxide and nitrogen dioxide with ECMWF's Composition-IFS
Summary: The paper presents results from data assimilation studies with the new Composition-IFS model developed in the MACC project. This system was used in MACC to produce daily analyses and 5-day forecasts of atmospheric composition and is now run daily in the EU’s Copernicus Atmosphere Monitoring Service. The paper looks at the quality of the CO, O3 and NO2 analysis fields obtained with this system comparing them against observations, a control run and an older version of the model.
A. Inness, A.-M. Blechschmidt, I. Bouarar, S. Chabrillat, M. Crepulja, R. J. Engelen, H. Eskes, J. Flemming, A. Gaudel, F. Hendrick, V. Huijnen, L. Jones, J. Kapsomenakis, E. Katragkou, A. Keppens, B. Langerock, M. de Mazière, D. Melas, M. Parrington, V. H. Peuch, M. Razinger, A. Richter, M. G. Schultz, M. Suttie, V. Thouret, M. Vrekoussis, A. Wagner, and C. Zerefos Atmos. Chem. Phys. Discuss., 15, 4265-4331, 2015 AbstractDiscussion Paper (PDF, 10209 KB)Supplement (1934 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACPSpecial Issue
17 Feb 2015
Model studies of volatile diesel exhaust particle formation: organic vapours involved in nucleation and growth?
Investigating the frequency and trends in global above-cloud aerosol characteristics with CALIOP and OMI
Summary: The spatial distributions and trends of aerosol above cloud (ACA) events are studied using seven and a half years of MODIS, OMI and CALIOP data. The active- (CALIOP) and passive-based (MODIS-OMI) methods have their advantages and caveats, and thus both are used to get a thorough and robust comparison of ACA distribution and climatology. For the first time, baseline above cloud CALIOP aerosol optical depth and OMI aerosol index thresholds are derived and examined for each sensor.
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
C. E. Scott, D. V. Spracklen, J. R. Pierce, I. Riipinen, S. D. D'Andrea, A. Rap, K. S. Carslaw, P. M. Forster, M. Kulmala, G. W. Mann, and K. J. Pringle Atmos. Chem. Phys. Discuss., 15, 4145-4172, 2015 AbstractDiscussion Paper (PDF, 787 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
17 Feb 2015
Formation of hydroxyl radicals from photolysis of secondary organic aerosol material
Summary: This is the first paper to demonstrate that SOA material forms OH radicals upon UV illumination. We quantify the OH formation rates in solution and show species other than H2O2, mostly probably ROOH molecules, are the likely source of the OH. The importance of an OH source from SOA is that photochemical processing within both cloudwater and aerosol particles may arise subsequent to the formation of these radicals.
K. M. Badali, S. Zhou, D. Aljawhary, M. Antiñolo, W. J. Chen, A. Lok, E. Mungall, J. P. S. Wong, R. Zhao, and J. P. D. Abbatt Atmos. Chem. Phys. Discuss., 15, 4117-4143, 2015 AbstractDiscussion Paper (PDF, 458 KB)Supplement (331 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
17 Feb 2015
Regional differences in Chinese SO2 emission control efficiency and policy implications
Summary: We found that SO2 emission reduction over NC is most effective in reducing national-mean surface sulfate concentrations and sulfur export fluxes, with β being 0.76 and 0.95 respectively, while SO2 emission reduction over SC has the highest β in reducing PWC (β = 0.98). The policy implication is that China needs to carefully design a regionally specific implementation plan of realizing its SO2 emissions reduction target in order to maximize the resulting air quality benefits .
Survival and ice nucleation activity of bacteria as aerosols in a cloud simulation chamber
Summary: - We determined mortality rate of typical bacterial aerosols (Pseudomonas species)
- Ice nucleation activity remained unchanged for several hours in aerosolized cells, whether they were viable or not
- Cloud increased the specific removal of ice nucleation active cells by precipitation
- Survival was impacted by the presence of cloud and by sulfates
Statistical exploration of gaseous elemental mercury (GEM) measured at Cape Point from 2007 to 2011
Summary: Statistical techniques applied to continuous high-resolution Hg data and back-trajectory analyses showed lower GEM concentrations originating from the sparsely populated semi-arid interior of SA and the marine environment, whereas higher GEM concentrations coincided with trade routes and industrial activities along the coast. Multi-linear regression indicated the relation of GEM with other atmospheric parameters. Measured and MLR data confirm a decline in GEM concentrations at CPT GAW station.
A. D. Venter, J. P. Beukes, P. G. van Zyl, E.-G. Brunke, C. Labuschagne, F. Slemr, R. Ebinghaus, and H. Kock Atmos. Chem. Phys. Discuss., 15, 4025-4053, 2015 AbstractDiscussion Paper (PDF, 1031 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
12 Feb 2015
Technical Note: Optical properties of desert dust with non-spherical particles: data incorporated to OPAC
Summary: Desert dust particles in general are not spherical, which changes their scattering functions against that for spheres that often are used for remote sensing and radiation budget investigations. In the new version of the data base OPAC (Optical Properties of Aerosols and Clouds), which easily allows one to model a large range of microphysical and optical aerosol properties for individually decided component mixtures, now typical non-spherical mineral particles are taken into account.
Wind extraction potential from ensemble Kalman filter assimilation of stratospheric ozone using a global shallow water model
Summary: While direct wind observations are routinely made in the troposphere (0-10 km), in the stratosphere (above 10 km) wind observations are sparse. This study examines the potential of using ozone observations to infer stratospheric wind. This novel approach is tested with a data assimilation system based on a simplified model of the atmosphere, the so-called "shallow water model". It is shown that assimilation of ozone observations significantly benefits winds, particularly in the tropics
Vertical profiles of optical and microphysical particle properties above the northern Indian Ocean during CARDEX 2012
Summary: The paper presents aerosol properties measured during the Cloud Aerosol Radiative Forcing Experiment (CARDEX) on the Maldives Islands in winter 2012. The vertical distribution of absorbing aerosol which is very relevant to the radiative forcing in that region, is investigated. A method for determining particle absorption and equivalent black carbon concentration from Lidar extinction measurements, characteristic single scattering albedo and mass absorption efficiency, is presented and evaluated.
F. Höpner, F. A.-M. Bender, A. M. L. Ekman, P. S. Praveen, C. Bosch, J. A. Ogren, A. Andersson, Ö. Gustafsson, and V. Ramanathan Atmos. Chem. Phys. Discuss., 15, 3907-3953, 2015 AbstractDiscussion Paper (PDF, 1125 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
12 Feb 2015
On the competition among aerosol number, size and composition in predicting CCN variability: a multi-annual field study in an urbanized desert
E. Crosbie, J.-S. Youn, B. Balch, A. Wonaschütz, T. Shingler, Z. Wang, W. C. Conant, E. A. Betterton, and A. Sorooshian Atmos. Chem. Phys. Discuss., 15, 3863-3906, 2015 AbstractDiscussion Paper (PDF, 4848 KB)Supplement (1077 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
10 Feb 2015
Climate responses to anthropogenic emissions of short-lived climate pollutants
L. H. Baker, W. J. Collins, D. J. L. Olivié, R. Cherian, Ø. Hodnebrog, G. Myhre, J. Quaas, and B. H. Samset Atmos. Chem. Phys. Discuss., 15, 3823-3862, 2015 AbstractDiscussion Paper (PDF, 4457 KB)Supplement (4387 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
10 Feb 2015
Successes and challenges of measuring and modeling atmospheric mercury at the part per quadrillion level: a critical review
Summary: The Minamata Convention for mercury (Hg) has been signed by many nations and the primary objective is to protect human health and the environment from releases of Hg. A key challenge researchers is developing linkages between Hg in the atmosphere, deposition, and ecosystem contamination. Here we critically review where the science on measuring and modeling atmospheric Hg stands and offer suggestions for future research that will both advance understanding of Hg cycling and serve the Convention.
Water soluble aerosols and gases at a UK background site – Part 1: Controls of PM2.5 and PM10 aerosol composition
Summary: Hourly inorganic composition of UK background particulate matter (PM10 and PM2.5) has been studied for a 6.5 year period at Auchencorth Moss, Scotland. Long range transport of both anthropogenic secondary and natural primary PM is observed, driven primarily by meteorology. The importance of nitrate, sulphate and ammonium during pollution events in the UK is demonstrated.
M. M. Twigg, C. F. Di Marco, S. Leeson, N. van Dijk, M. R. Jones, I. D. Leith, E. Morrison, M. Coyle, R. Proost, A. N. M. Peeters, E. Lemon, T. Frelink, C. F. Braban, E. Nemitz, and J. N. Cape Atmos. Chem. Phys. Discuss., 15, 3703-3743, 2015 AbstractDiscussion Paper (PDF, 2926 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
09 Feb 2015
Experimental investigation of ion-ion recombination at atmospheric conditions
Summary: The ion-ion recombination coefficient was measured at different temperatures, relative humidities and concentrations of ozone and sulfur dioxide. The experiments were carried out using the CLOUD chamber at CERN.
We observed a strong dependency on temperature and on relative humidity, which has not been reported previously. No dependency of the ion-ion recombination coefficient on ozone concentration and a weak variation with sulfur dioxide concentration were also observed.
A. Franchin, S. Ehrhart, J. Leppä, T. Nieminen, S. Gagné, S. Schobesberger, D. Wimmer, J. Duplissy, F. Riccobono, E. Dunne, L. Rondo, A. Downard, F. Bianchi, A. Kupc, G. Tsagkogeorgas, K. Lehtipalo, H. E. Manninen, J. Almeida, A. Amorim, P. E. Wagner, A. Hansel, J. Kirkby, A. Kürten, N. M. Donahue, V. Makhmutov, S. Mathot, A. Metzger, T. Petäjä, R. Schnitzhofer, M. Sipilä, Y. Stozhkov, A. Tomé, V.-M. Kerminen, K. Carslaw, J. Curtius, U. Baltensperger, and M. Kulmala Atmos. Chem. Phys. Discuss., 15, 3667-3702, 2015 AbstractDiscussion Paper (PDF, 1136 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACPSpecial Issue
09 Feb 2015
Peroxynitric acid (HO2NO2) measurements during the UBWOS 2013 and 2014 studies using iodide ion chemical ionization mass spectrometry
P. R. Veres, J. M. Roberts, R. J. Wild, P. M. Edwards, S. S. Brown, T. S. Bates, P. K. Quinn, J. E. Johnson, R. J. Zamora, and J. de Gouw Atmos. Chem. Phys. Discuss., 15, 3629-3666, 2015 AbstractDiscussion Paper (PDF, 6860 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACPSpecial Issue
09 Feb 2015
Predicting the mineral composition of dust aerosols – Part 2: Model evaluation and identification of key processes with observations
Summary: A global compilation from nearly sixty measurement studies is used to evaluate two methods of simulating the mineral composition of dust aerosols. Dust emission based on wet-sieved soil is assumed for the first method. The second method reconstructs the aggregates and size distribution of the original soil before emission. Only the second method is able to reproduce observed phyllosilicate fractions in the silt size range and reduces quartz overestimation. Substantial uncertainties remain.
Predicting the mineral composition of dust aerosols – Part 1: Representing key processes
Summary: The mineral composition of dust aerosols is modeled. The mineral composition is derived by extending a method that provides the composition of wet-sieved soil to account for differences between the mineral fractions of the wet-sieved soil and the resulting aerosol concentration. An empirical constraint upon the relative emission of clay and silt is applied that further differentiates soil and aerosol mineral composition. A method is proposed for mixing minerals with iron oxide impurities.
Increasing and decreasing trends of the atmospheric deposition of organochlorine compounds in European remote areas during the last decade
Summary: Despite the regulations in the use of polychlorobiphenyls (PCBs), an increase in atmospheric deposition fluxes of these pollutants in high altitude mountain areas of Europe is observed for the period between 1996 and 2006. In contrast, atmospheric deposition of organochlorine pesticides showed a strong decrease. Volatilization from soils or melting glaciers related to climate change and the differences in physical-chemical properties between compounds may explain the observed temporal trend.
L. Arellano, P. Fernández, R. Fonts, N. L. Rose, U. Nickus, H. Thies, E. Stuchlík, L. Camarero, J. Catalan, and J. O. Grimalt Atmos. Chem. Phys. Discuss., 15, 3415-3453, 2015 AbstractDiscussion Paper (PDF, 2030 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
06 Feb 2015
Vertical variation of optical properties of mixed Asian dust/pollution plumes according to pathway of airmass transport over East Asia
Summary: The measurements from 2009 to 2013 by using a multiwavelength Raman lidar were conducted to identify the changes of optical properties of East Asian dust. We found that the optical properties of Asian dust change in dependence of the dust plume's vertical position and the change of vertical position during transport over China. We believe this paper provides a better understanding of the optical properties of mixed Asian dust plums and the effect of long-range transport on dust properties.
Low hygroscopic scattering enhancement of boreal aerosol and the implications for a columnar optical closure study
P. Zieger, P. P. Aalto, V. Aaltonen, M. Äijälä, J. Backman, J. Hong, M. Komppula, R. Krejci, M. Laborde, J. Lampilahti, G. de Leeuw, A. Pfüller, B. Rosati, M. Tesche, P. Tunved, R. Väänänen, and T. Petäjä Atmos. Chem. Phys. Discuss., 15, 3327-3379, 2015 AbstractDiscussion Paper (PDF, 5542 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
05 Feb 2015
Impacts of atmospheric circulations on aerosol distributions in autumn over eastern China: observational evidences
Summary: We systematically examined that how various large scale atmospheric conditions (ACs) affects the distributions of aerosol optical depth over the East China.We extract and depict nine main types for ACs-effect AOD (six polluted types and three clean types) in autumn over East China. The results provide convincing evidences that the general characteristics of atmospheric circulations contribute significantly to the different types of regional pollution.
Black carbon emissions from Russian diesel sources: case study of Murmansk
Summary: We estimated BC emissions from diesel sources in Murmansk Region and Murmansk City, the largest city in the Arctic. We developed a detailed inventory including on-road vehicles, off-road transport (mining, locomotives, construction and agriculture), fishing and diesel generators. We conducted several surveys to understand the vehicle fleet and driving patterns. BC emissions in Murmansk Region were 0.40 Gg in 2012. Total BC emissions from diesel sources in Russia estimated at 56.7 Gg in 2010.
In situ vertical profiles of aerosol extinction, mass, and composition over the southeast United States during SENEX and SEAC4RS: observations of a modest aerosol enhancement aloft
Summary: This paper investigates the summertime vertical profile of aerosol over the southeastern US using in situ measurements collected from aircraft. We use a vertical mixing model and measurements of CO to predict the vertical profile of aerosol that we would expect from vertical mixing alone and compare with the observed aerosol profile. We found a modest enhancement of aerosol in the cloudy transition layer during shallow cumulus convection and attribute the enhancement to local aerosol formation.
N. L. Wagner, C. A. Brock, W. M. Angevine, A. Beyersdorf, P. Campuzano-Jost, D. A. Day, J. A. de Gouw, G. S. Diskin, T. D. Gordon, M. G. Graus, G. Huey, J. L. Jimenez, D. A. Lack, J. Liao, X. Liu, M. Z. Markovic, A. M. Middlebrook, T. Mikoviny, J. Peischl, A. E. Perring, M. S. Richardson, T. B. Ryerson, J. P. Schwarz, C. Warneke, A. Welti, A. Wisthaler, L. D. Ziemba, and D. M. Murphy Atmos. Chem. Phys. Discuss., 15, 3127-3172, 2015 AbstractDiscussion Paper (PDF, 4777 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
03 Feb 2015
Ozone and aerosols tropospheric concentrations variability analyzed using the ADRIMED measurements and the WRF-CHIMERE models
Summary: The ozone and aerosols concentrations variability is studied over the Euro-Mediterranean area during the months of June and July 2013 and in the framework of the ADRIMED project. A first analysis is performed using meteorological variables, ozone and aerosols concentrations using routine stations network, satellite and specific ADRIMED project airborne measurements. This analysis is complemented by modelling using the WRF and CHIMERE regional models.
Nighttime measurements of HOx during the RONOCO project and analysis of the sources of HO2
H. M. Walker, D. Stone, T. Ingham, S. Vaughan, B. Bandy, M. Cain, R. L. Jones, O. J. Kennedy, M. McLeod, B. Ouyang, J. Pyle, S. Bauguitte, G. Forster, M. J. Evans, J. F. Hamilton, J. R. Hopkins, J. D. Lee, A. C. Lewis, R. T. Lidster, S. Punjabi, W. T. Morgan, and D. E. Heard Atmos. Chem. Phys. Discuss., 15, 2997-3061, 2015 AbstractDiscussion Paper (PDF, 4643 KB)Supplement (131 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACPSpecial Issue
30 Jan 2015
Photochemical processing of aqueous atmospheric brown carbon
Summary: Aqueous-phase photochemical decay of light absorbing organic compounds, or Atmospheric Brown Carbon (BrC), is investigated in this study. The absorptive change of laboratory surrogates of BrC, as well as biofuel combustion samples, were monitored during photolysis and OH oxidation experiments. The major finding is the rapid change in the absorptivity of BrC during such photochemical processing. This change should be taken into account to evaluate the importance of BrC in the atmosphere.
CFD modeling of a vehicle exhaust laboratory sampling system: sulfur driven nucleation and growth in diluting diesel exhaust
Summary: This article presents a new model that simulates particle formation in vehicle exhaust. The model is used to examine particle dynamics, such as nucleation, inside a diesel exhaust laboratory sampling system. The results suggest lower slope of nucleation rate versus sulfuric acid concentration than previously found.
Observations of relative humidity effects on aerosol light scattering in the Yangtze River Delta of China
Summary: The aerosol hygroscopic properties at a rural background site in the Yangtze River Delta of China was discussed. The result shows the scattering coefficient and backscattering coefficient increased by 58% and 25% as relative humidity (RH) increased from 40% to 85%; while the hemispheric backscatter fraction decreased by 21%. Aerosol direct forcing increased by 16% at ambient mean RH of 67% due to the water uptake at LinAn in March,2013. Nitrate played a vital role in the aerosol hygroscopicity.
L. Zhang, J. Y. Sun, X. J. Shen, Y. M. Zhang, H. C. Che, Q. L. Ma, Y. W. Zhang, X. Y. Zhang, and J. A. Ogren Atmos. Chem. Phys. Discuss., 15, 2853-2904, 2015 AbstractDiscussion Paper (PDF, 2718 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACP
29 Jan 2015
Formation of highly oxidized multifunctional compounds: autoxidation of peroxy radicals formed in the ozonolysis of alkenes – deduced from structure–product relationships
Summary: We studied a series of cycloalkenes and methyl substituted alkenes in order to elucidate the structural pre-requisites and chemical pathways to the recently discovered class of highly oxidized molecules ELVOC (Ehn et al., Nature, 2014). ELVOC may totally change the view on (parts of) the mechanism of SOA formation. We present results which support recent observations H-shifts from C-H to peroxy radicals, highlighting the pivotal role of peroxyradical in organic atmospheric chemistry.
The relationship between cloud condensation nuclei (CCN) concentration and light extinction of dried particles: indications of underlying aerosol processes and implications for satellite-based CCN estimates
Y. Shinozuka, A. D. Clarke, A. Nenes, A. Jefferson, R. Wood, C. S. McNaughton, J. Ström, P. Tunved, J. Redemann, K. L. Thornhill, R. H. Moore, T. L. Lathem, J. J. Lin, and Y. J. Yoon Atmos. Chem. Phys. Discuss., 15, 2745-2789, 2015 AbstractDiscussion Paper (PDF, 823 KB)Supplement (399 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
29 Jan 2015
Secondary Organic Aerosol (SOA) formation from the β-pinene + NO3 system: effect of humidity and peroxy radical fate
Summary: Laboratory chamber studies were conducted to investigate the formation of secondary organic aerosol from β-pinene oxidation by nitrate radicals. These experiments probed the effects of peroxy radical fate and relative humidity on the mass and chemical composition of secondary organic aerosol formed from nighttime chemistry. Results from this study were used to evaluate the contributions of NO3+monoterpene reaction to ambient organic aerosol recently measured in the southeastern United States.
Multi-model simulation of CO and HCHO in the Southern Hemisphere: biogenic emissions and model uncertainties
Summary: We assess the impact of biogenic emissions on CO and HCHO in the Southern Hemisphere (SH), with simulations using different emission inventories. Differences in biogenic emissions result in large differences on modelled CO in the source and the remote regions. Substantial inter-model differences exist. Models significantly underestimate observed HCHO columns in the SH, suggesting missing sources in the models. Differences in the CO/OH/CH4 chemistry lead to differences in HCHO in remote regions.
G. Zeng, J. E. Williams, J. A. Fisher, L. K. Emmons, N. B. Jones, O. Morgenstern, J. Robinson, D. Smale, C. Paton-Walsh, and D. W. T. Griffith Atmos. Chem. Phys. Discuss., 15, 2615-2678, 2015 AbstractDiscussion Paper (PDF, 6581 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACP
27 Jan 2015
An ecosystem-scale perspective of the net land methanol flux: synthesis of micrometeorological flux measurements
Summary: Methanol is the second most abundant volatile organic compound in the troposphere and plays a significant role in atmospheric chemistry. While there is consensus about the dominant role of plants as the major source and the reaction with OH as the major sink, global methanol budgets diverge considerably in terms of source/sink estimates. Here we present micrometeorological methanol flux data from eight 8 sites in order to provide a first cross-site synthesis of the terrestrial methanol exchange.
G. Wohlfahrt, C. Amelynck, C. Ammann, A. Arneth, I. Bamberger, A. H. Goldstein, L. Gu, A. Guenther, A. Hansel, B. Heinesch, T. Holst, L. Hörtnagl, T. Karl, Q. Laffineur, A. Neftel, K. McKinney, J. W. Munger, S. G. Pallardy, G. W. Schade, R. Seco, and N. Schoon Atmos. Chem. Phys. Discuss., 15, 2577-2613, 2015 AbstractDiscussion Paper (PDF, 2317 KB)Supplement (570 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
27 Jan 2015
Stratosphere–troposphere exchange (STE) in the vicinity of North Atlantic cyclones
Summary: In this manuscript, we investigate the exchange of air masses across the dynamical tropopause (stratosphere-troposphere exchange, STE) in the vicinity of North Atlantic cyclones. By using two 6-hourly resolved ERA-Interim climatologies of STE and cyclones from 1979 to 2011, we are able to directly compute the amount of STE in the vicinity of every individual cyclone in this time period. This enables us to provide a robust and consistent quantification of STE near North Atlantic cyclones.
Assessment of crop yield losses in Punjab and Haryana using two years of continuous in-situ ozone measurements
Summary: We use ozone measurements at a suburban site in Punjab to estimated ozone related crop yield losses for wheat, rice, cotton and maize for the states Punjab and Haryana for the years 2011-2013. Crop production losses amount to 10.3-20.8 Mt y-1 for wheat & 3.2-5.4 Mt y-1 for rice enough to feed 225-437 million of India’s poor. The lower limit for the ozone related economic losses is 3.7-6.5 billion USD (Punjab & Haryana), while the upper limit amounts to 3.5%-20% of the Indian GDP (entire India).
Evolution of gaseous precursors and meteorological parameters during new particle formation events in the Central European boundary layer
Summary: This paper revisits the atmospheric new particle formation (NPF) process in the polluted troposphere. Novel aspects include a new NPF classification, which aims at more objectivity, and a long-term collection of Neutral Cluster and Air Ion Spectrometer data. Intense NPF events were associated with enhanced sulphur dioxide precursor concentrations while no exclusive correlations were observed with the condensation sink, surface-measured turbulence parameters or ammonia.
J. Größ, W. Birmili, A. Hamed, A. Sonntag, A. Wiedensohler, G. Spindler, H. E. Maninnen, T. Nieminen, M. Kulmala, U. Hõrrak, and C. Plass-Dülmer Atmos. Chem. Phys. Discuss., 15, 2305-2353, 2015 AbstractDiscussion Paper (PDF, 2592 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
23 Jan 2015
LIVAS: a 3-D multi-wavelength aerosol/cloud climatology based on CALIPSO and EARLINET
V. Amiridis, E. Marinou, A. Tsekeri, U. Wandinger, A. Schwarz, E. Giannakaki, R. Mamouri, P. Kokkalis, I. Binietoglou, S. Solomos, T. Herekakis, S. Kazadzis, E. Gerasopoulos, D. Balis, A. Papayannis, C. Kontoes, K. Kourtidis, N. Papagiannopoulos, L. Mona, G. Pappalardo, O. Le Rille, and A. Ansmann Atmos. Chem. Phys. Discuss., 15, 2247-2304, 2015 AbstractDiscussion Paper (PDF, 9642 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACP
23 Jan 2015
Uncertainties in isoprene photochemistry and emissions: implications for the oxidative capacity of past and present atmospheres and for trends in climate forcing agents
Summary: The atmosphere’s oxidative capacity determines the lifetime of many trace gases important to climate, chemistry, and human health. Yet uncertainties remain about its past variations, its controlling factors, and the radiative forcing of short-lived species it influences. To reduce these uncertainties, we must better quantify the natural emissions and chemical reaction mechanisms of organic compounds in the atmosphere, which play a role in governing the oxidative capacity.
P. Achakulwisut, L. J. Mickley, L. T. Murray, A. P. K. Tai, J. O. Kaplan, and B. Alexander Atmos. Chem. Phys. Discuss., 15, 2197-2246, 2015 AbstractDiscussion Paper (PDF, 573 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
23 Jan 2015
Temporal and spatial scaling impacts on extreme precipitation
A comparison of measured HONO uptake and release with calculated source strengths in a heterogeneous forest environment
Summary: We measured near surface (< 2 m) profiles of HONO in a clearing and on a forest floor. Both HONO deposition and emission were observed. By comparing three postulated sources to observed daytime emissions, we made several important findings: ● conversion of NO2 is mostly independent of light due to light saturation ● HONO emissions from a very acidic soil were low ● photolysis of adsorbed HNO3 could serve as HONO source based on empirical parameters but unlikely via the proposed reaction pathway
Separating refractory and non-refractory particulate chloride and estimating chloride depletion by aerosol mass spectrometry in a marine environment
Summary: In this paper, we focus on the measurement and reporting of mass concentrations of particulate chloride and sea salt in a marine area off the coast of California using a High Resolution Aerosol Mass Spectrometer. We outline a method of deconvolving the total aerosol chloride mass into refractory and non-refractory components, previously not reported in the literature. This can be important in regions where refractory sea salt aerosols can contribute to the aerosol chloride signal measured with t
I. Nuaaman, S.-M. Li, K. L. Hayden, T. B. Onasch, P. Massoli, D. Sueper, D. R. Worsnop, T. S. Bates, P. K. Quinn, and R. McLaren Atmos. Chem. Phys. Discuss., 15, 2085-2118, 2015 AbstractDiscussion Paper (PDF, 2905 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
22 Jan 2015
Understanding atmospheric peroxyformic acid chemistry: observation, modeling and implication
Summary: The present field measurements have provided strong evidence for the existence of peroxyformic acid (HC(O)OOH) in the atmosphere for the first time. Moreover, the potential impact of peroxyformic acid chemistry on the formic acid production and the radical budget has been evaluated on the basis of model calculations. Our findings are of importance for a full understanding of the cycling of oxidants and the source of organic acids in the atmosphere.
Elevated uptake of CO2 over Europe inferred from GOSAT XCO2 retrievals: a real phenomenon or an artefact of the analysis?
Summary: There is an on-going debate on the larger European biospheric uptake inferred from GOSAT XCO2 retrievals than those inferred from in situ data. Using a set of 15 experiments, we found that the elevated uptake over Europe could largely be explained by mis-fitting data due to regional XCO2 biases: 50-80% of the elevated European uptake is due to retrievals outside the immediate European; and a varying monthly bias of upto 0.5 ppm for XCO2 retrievals over Europe could explain most of the remainder.
L. Feng, P. I. Palmer, R. J. Parker, N. M. Deutscher, D. G. Feist, R. Kivi, I. Morino, and R. Sussmann Atmos. Chem. Phys. Discuss., 15, 1989-2011, 2015 AbstractDiscussion Paper (PDF, 339 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
21 Jan 2015
Observations and analysis of organic aerosol evolution in some prescribed fire smoke plumes
Summary: Smoke plumes from some prescribed fires in the Southeastern United States were sampled via aircraft to observe changes in organic aerosol (OA) with atmospheric transport. These plumes underwent rapid mixing, and hence, substantial dilution with background air occurred. Dilution-driven evaporation appears to be the primary driver of OA transformations within the sampled plumes rather than photochemistry.
A. A. May, T. Lee, G. R. McMeeking, S. Akagi, A. P. Sullivan, S. Urbanski, R. J. Yokelson, and S. M. Kreidenweis Atmos. Chem. Phys. Discuss., 15, 1953-1988, 2015 AbstractDiscussion Paper (PDF, 682 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACP
21 Jan 2015
On the ability of a global atmospheric inversion to constrain variations of CO2 fluxes over Amazonia
L. Molina, G. Broquet, P. Imbach, F. Chevallier, B. Poulter, D. Bonal, B. Burban, M. Ramonet, L. V. Gatti, S. C. Wofsy, J. W. Munger, E. Dlugokencky, and P. Ciais Atmos. Chem. Phys. Discuss., 15, 1915-1952, 2015 AbstractDiscussion Paper (PDF, 3066 KB)Interactive Discussion (Open, 3 Comments)Manuscript under review for ACPSpecial Issue
21 Jan 2015
Trends and drivers of ozone human health and vegetation impact metrics from UK EMEP supersite measurements (1990–2013)
Summary: Health and vegetation relevant ozone exposure metrics (SOMO10/SOMO35 and PODY/AOT40 respectively) are analysed between 1990-2013 using data from the UK EMEP supersites: Auchencorth Moss, southern Scotland and Harwell, south-east England. Analysis shows for health-relevant ozone exposure, improvement has been achieved for SOMO35 but not for SOMO10 despite European mitigation strategies reducing precursor emissions. Vegetation impacts based on PODY have also not decreased.
Effects of global change during the 21st century on the nitrogen cycle
D. Fowler, C. E. Steadman, D. Stevenson, M. Coyle, R. M. Rees, U. M. Skiba, M. A. Sutton, J. N. Cape, A. J. Dore, M. Vieno, D. Simpson, S. Zaehle, B. D. Stocker, M. Rinaldi, M. C. Facchini, C. R. Flechard, E. Nemitz, M. Twigg, J. W. Erisman, and J. N. Galloway Atmos. Chem. Phys. Discuss., 15, 1747-1868, 2015 AbstractDiscussion Paper (PDF, 3689 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACPSpecial Issue
20 Jan 2015
Deuterium excess in atmospheric water vapor of a Mediterranean coastal wetland: regional versus local signatures
Summary: Based on summer measurements of δ18O and δD in atmospheric vapor of a Mediterranean coastal wetland, this paper explores the main drivers of isotopic signal variability at different time scales. The daily time scale is related to regional air mass trajectories, while diurnal variations are discussed with regards to the contribution of local evapotranspiration to the water budget of the Planetary Boundary Layer.
Mapping gas-phase organic reactivity and concomitant secondary organic aerosol formation: chemometric dimension reduction techniques for the deconvolution of complex atmospheric datasets
Summary: This paper describes a new ensemble methodology for the statistical analysis of atmospheric gas- & particle-phase composition data sets. The methodology reduces the huge amount of data derived from many chamber experiments to show that organic reactivity & resultant particle formation can be mapped into unique clusters in statistical space. The model generated is used to map more realistic plant mesocosm oxidation data, the projection of which gives insight into reactive pathways & precursors.
K. P. Wyche, P. S. Monks, K. L. Smallbone, J. F. Hamilton, M. R. Alfarra, A. R. Rickard, G. B. McFiggans, M. E. Jenkin, W. J. Bloss, A. C. Ryan, C. N Hewitt, and A. R MacKenzie Atmos. Chem. Phys. Discuss., 15, 1651-1702, 2015 AbstractDiscussion Paper (PDF, 4972 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACP
20 Jan 2015
An objective determination of optimal site locations for detecting expected trends in upper-air temperature and total column ozone
Summary: This manuscript aims to answer the following question: Which of the existing sites engaged in upper-air temperature measurements are best located to detect expected future trends within the shortest time possible. To do so, we explore one objective method for selecting the optimal locations for detecting projected 21st century trends and then demonstrate a similar technique for objectively selecting optimal locations for detecting expected future trends in total column ozone.
Ice phase in altocumulus clouds over Leipzig: remote sensing observations and detailed modelling
Summary: The paper combines remote sensing observations and detailed cloud modeling. It was shown that the main features of the observations could be captured which allows to perform sensitivity studies. Those show that the liquid phase is mainly determined by the dynamical parameters of the model whereas the ice phase is dominated by microphysical parameters such as ice nuclei number and ice particle shape.
The climatology of dust aerosol over the arabian peninsula
Summary: Dust storms are considered to be a natural hazard over the Arabian Peninsula, since they occur all year round with maximum intensity and frequency in Spring and Summer. AERONET, MODIS, MISR, OMI datasets have been analyzed to study atmospheric dust over Arabia also a 13 years simulation has been performed to study the dust climatology. The study showed how dust aerosol climatology changes from northern Arabia to southern Arabia and how this may impact the region climatology.
Evaluation of the GEM-AQ model in the context of the AQMEII Phase 1 project
Summary: In the scope of the AQMEII Phase 1 project the GEM-AQ model was run over Europe with the resolution of 0.2ox0.2o, for the year 2006. Spatial distribution and temporal variability of the GEM-AQ model results were analysed for surface ozone and PM10 concentrations in the context of regional climate characteristics. The GEM-AQ model performance was characterised for station types, European climatic regions, and seasons.
J. Struzewska, M. Zdunek, J. W. Kaminski, L. Lobocki, M. Porebska, M. Jefimow, and L. Gawuc Atmos. Chem. Phys. Discuss., 15, 1471-1522, 2015 AbstractDiscussion Paper (PDF, 11666 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACP
19 Jan 2015
Observations and simulations of three-dimensional radiative interactions between Arctic boundary layer clouds and ice floes
Deposition and immersion mode nucleation of ice by three distinct samples of volcanic ash using Raman spectroscopy
Summary: Fine volcanic ash can influence cloud glaciation and, therefore, global climate. In this work we examined the heterogeneous ice nucleation properties of three distinct types of volcanic ash. We find that, in contrast to previous studies, these volcanic ash samples have different ice nucleation properties in the immersion mode. In the deposition mode, however, they nucleate ice with similar efficiency. We show that this behavior may be due to their mineralogy.
One year of Raman lidar observations of free tropospheric aerosol layers over South Africa
Summary: In this study we summarize one year of Raman lidar observations over South Africa. The analyses of lidar measurements presented here could assist in bridging existing gaps on the knowledge of vertical distribution of aerosols above South Africa, since limited long-term data of this type is available for this region. For the first time, we have been able to cover the full seasonal cycle on geometrical characteristics and optical properties of free tropospheric aerosol layers in the region.
E. Giannakaki, A. Pfüller, K. Korhonen, T. Mielonen, L. Laakso, V. Vakkari, H. Baars, R. Engelmann, J. P. Beukes, P. G. Van Zyl, M. Josipovic, P. Tiitta, K. Chiloane, S. Piketh, H. Lihavainen, K. E. J. Lehtinen, and M. Komppula Atmos. Chem. Phys. Discuss., 15, 1343-1384, 2015 AbstractDiscussion Paper (PDF, 2322 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
16 Jan 2015
Insights into the chemical composition of summertime PM2.5 at the northeast of the Qinghai-Xizang (Tibet) Plateau
Free amino acids in Antarctic aerosol: potential markers for the evolution and fate of marine aerosol
E. Barbaro, R. Zangrando, M. Vecchiato, R. Piazza, W. R. L. Cairns, G. Capodaglio, C. Barbante, and A. Gambaro Atmos. Chem. Phys. Discuss., 15, 1269-1305, 2015 AbstractDiscussion Paper (PDF, 3072 KB)Supplement (110761 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
15 Jan 2015
Step changes in persistent organic pollutants over the Arctic and their implications
Summary: After several decades declining of persistent organic pollutants in the arctic environment due to their global use restriction, some of these toxic chemicals increased in the mid-2000s and undertook statistically significant step changes which coincided with arctic sea ice melting. Results provide statistical evidence for the releasing of toxic chemicals from their reservoirs in the Arctic due to the rapid change in the arctic environment.
Lidar observations of Nabro volcano aerosol layers in the stratosphere over Gwangju, Korea
Summary: We present for the first time results of Raman lidar observations of the temporal evolution of a stratospheric aerosol layer observed in the upper troposphere and lower stratosphere over Korea. We find what non-spherical particles may have been present in the lower stratosphere for at least six months after the eruption on the volcano. Our study adds to the limited information on volcanic aerosols over East Asia.
D. Shin, D. Müller, K. Lee, S. Shin, Y. J. Kim, C. K. Song, and Y. M. Noh Atmos. Chem. Phys. Discuss., 15, 1171-1191, 2015 AbstractDiscussion Paper (PDF, 3925 KB)Interactive Discussion (Open, 3 Comments)Manuscript under review for ACP
14 Jan 2015
Relative humidity-dependent viscosities of isoprene-derived secondary organic material and atmospheric implications for isoprene-dominant forests
Modeling the feedback between aerosol and meteorological variables in the atmospheric boundary layer during a severe fog-haze event over the North China Plain
Summary: By using a online coupled meteorology and aerosol/chemistry model (WRF-Chem), the increase of surface PM2.5 concentration is estimated up to be 30% during a severe fog-haze event (10~15 January 2013) over North China Plain owing to the aerosol-induced decrease surface temperature, wind speed and atmosphere boundary layer height, increase surface relative humidity, and more stable atmosphere. A mechanism of positive feedback exists and contributes to the formation of fog-haze events.
The impact of overshooting deep convection on local transport and mixing in the tropical upper troposphere/lower stratosphere (UTLS)
Summary: This study examines the simulated downward transport and mixing of stratospheric air into the upper tropical troposphere as observed on a research flight during the SCOUT-O3 campaign in connection to a deep convective system, using the WRF model. Passive tracers are initialised to study the impact of the deep convection on the tracers and water vapour. We use the model to explain the processes causing the transport and also expose areas of inconsistencies between the model and observations.
W. Frey, R. Schofield, P. Hoor, D. Kunkel, F. Ravegnani, A. Ulanovsky, S. Viciani, F. D'Amato, and T. P. Lane Atmos. Chem. Phys. Discuss., 15, 1041-1091, 2015 AbstractDiscussion Paper (PDF, 7449 KB)Interactive Discussion (Open, 3 Comments)Manuscript under review for ACP
14 Jan 2015
Technical Note: A novel parameterization of the transmissivity due to ozone absorption in the k-distribution method and correlated-k approximation of Kato et al. (1999) over the UV band
Summary: A novel model of the absorption of radiation by ozone in the UV bands [283, 307] nm and [307, 328] nm yields improvements in the modelling of the transmissivity in these bands. This model is faster than detailed spectral calculations and is as accurate with maximum error of respectively 0.0006 and 0.0041. How to practically implement this new parameterization in a radiative transfer model is discussed for the case of libRadtran.
W. Wandji Nyamsi, A. Arola, P. Blanc, A. V. Lindfors, V. Cesnulyte, M. R. A. Pitkänen, and L. Wald Atmos. Chem. Phys. Discuss., 15, 1027-1040, 2015 AbstractDiscussion Paper (PDF, 1588 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACP
13 Jan 2015
Balancing aggregation and smoothing errors in inverse models
Chemical characterization of submicron regional background aerosols in the Western Mediterranean using an Aerosol Chemical Speciation Monitor
Summary: The study focuses on the aerosol variations taking place in the regional background of the Western Mediterranean Basin and their relation with atmospheric conditions and scenarios. An Aerosol Chemical Speciation Monitor (ACSM) was deployed for one year and the results were validated with co-located PM1 measurements. The organic sources were investigated and the local secondary organic aerosol (SOA) formation was estimated.
Impact of interannual variations in aerosol particle sources on orographic precipitation over California's Central Sierra Nevada
Summary: Aerosols impact how clouds and precipitation form. In the California Sierra Nevada, we found that the formation and resulting amount of rain and snow were impacted by mineral dust, bioparticles such as bacteria, and biomass burning and pollution particles during three winter seasons. Dust and bioparticles from distant sources impacted high altitude clouds by forming ice, leading to more precipitation, whereas local biomass burning and pollution entered the base of clouds leading to less rain.
J. M. Creamean, A. P. Ault, A. B. White, P. J. Neiman, F. M. Ralph, P. Minnis, and K. A. Prather Atmos. Chem. Phys. Discuss., 15, 931-964, 2015 AbstractDiscussion Paper (PDF, 3456 KB)Interactive Discussion (Open, 3 Comments)Manuscript under review for ACP
12 Jan 2015
Investigating the discrepancy between wet-suspension and dry-dispersion derived ice nucleation efficiency of mineral particles
Quantifying methane and nitrous oxide emissions from the UK using a dense monitoring network
Summary: The UK is one of several countries to enact legislation to reduce greenhouse gas emissions. We present top-down emissions of methane and nitrous oxide for the UK and Ireland. We inferred average UK emissions of 2.08 Tg/yr CH4 and 0.105 Tg/yr N2O and used sectoral distributions to determine whether these discrepancies can be attributed to specific source sectors. We found the agricultural sector likely to be overestimated in the bottom-up emissions inventory of both gases.
A. L. Ganesan, A. J. Manning, A. Grant, D. Young, D. E. Oram, W. T. Sturges, J. B. Moncrieff, and S. O'Doherty Atmos. Chem. Phys. Discuss., 15, 857-886, 2015 AbstractDiscussion Paper (PDF, 873 KB)Supplement (2090 KB)Interactive Discussion (Open, 3 Comments)Manuscript under review for ACP
09 Jan 2015
Comment on "Observation and modelling of HOx radicals in a boreal forest" by Hens et al. (2014)
Impacts of an unknown daytime nitrous acid source on its daytime concentration and budget, as well as those of hydroxyl, hydroperoxyl, and organic peroxy radicals, in the coastal regions of China
Summary: High daytime HONO mixing ratios in field experiments suggest that an unknown daytime HONO source (Punknown) could exist.Punknown≈19.60×NO2×J(NO2) was obtained using observed data from 13 field experiments across the globe,then coupled into the WRF-Chem model. Simulations indicated that elevated Punknown were found in the coastal regions of China; the additional HONO sources,especially the Punknown produced significant increases of radicals in the major cities,and accelerated the radical cycles.
A modified micrometeorological gradient method for estimating O3 dry deposition over a forest canopy
Summary: In this study, we have developed a modified micrometeorological gradient method (MGM), although based on existing micrometeorological theory, to estimate O3 dry deposition fluxes over a forest canopy using concentration gradients between a level above and a level below the canopy top. The new method provides an alternative approach in monitoring/estimating long-term deposition fluxes of similar pollutants over tall canopies and is expected to be useful for the scientific community.
Estimating NH3 emissions from agricultural fertilizer application in China using the bi-directional CMAQ model coupled to an agro-ecosystem model
Summary: In this study, we estimate, for the first time, the NH3 emission from the agricultural fertilizer application in China online using the bi-directional CMAQ model coupled to an agro-ecosystem model. Compared with previous researches, this method considers more influencing factors, such as meteorological fields, soil and the fertilizer application, and provides improved NH3 emission with higher spatial and temporal resolution.
Particulate matter, air quality and climate: lessons learned and future needs
Summary: Particulate matter (PM) constitutes one of the most challenging problems both for air quality and climate change policies. This paper reviews the most recent scientific results on the issue, and the policy needs that have driven much of the increase in monitoring and mechanistic research over the last two decades. The synthesis reveals many new processes and developments in the science underpinning climate-PM interactions and effects of PM on human health and the environment.
S. Fuzzi, U. Baltensperger, K. Carslaw, S. Decesari, H. Denier van der Gon, M. C. Facchini, D. Fowler, I. Koren, B. Langford, U. Lohmann, E. Nemitz, S. Pandis, I. Riipinen, Y. Rudich, M. Schaap, J. Slowik, D. V. Spracklen, E. Vignati, M. Wild, M. Williams, and S. Gilardoni Atmos. Chem. Phys. Discuss., 15, 521-744, 2015 AbstractDiscussion Paper (PDF, 5565 KB)Interactive Discussion (Open, 0 Comments)Manuscript under review for ACPSpecial Issue
08 Jan 2015
Drivers of the tropospheric ozone budget throughout the 21st century under the medium-high climate scenario RCP 6.0
L. E. Revell, F. Tummon, A. Stenke, T. Sukhodolov, A. Coulon, E. Rozanov, H. Garny, V. Grewe, and T. Peter Atmos. Chem. Phys. Discuss., 15, 481-519, 2015 AbstractDiscussion Paper (PDF, 2760 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
07 Jan 2015
The decrease in mid-stratospheric tropical ozone since 1991
Summary: While global stratospheric O3 has begun to recover, there are localized regions where O3 has decreased since 1991. O3 in the mid-stratosphere is very sensitive to nitrogen chemistry, with increased NOy resulting in decreased O3. We show how the observed O3 changes in the tropical mid-stratosphere can be caused by long-term variations in dynamics which result in a decrease in N2O, an increase in NOy, and a resulting decrease in O3.
Observations of PW activity in the MLT during SSW events using a chain of SuperDARN radars and SD-WACCM
Summary: Planetary wave activity measured in the mesosphere lower thermosphere is shown to increase drastically after strong stratospheric polar cap wind reversals associated with sudden stratospheric warmings. In addition, a moderate but significant correlation was found between planetary wave enhancement in the mesosphere lower thermosphere and all stratospheric polar cap wind reversals, irrespective of the strength of the reversal.
N. H. Stray, Y. J. Orsolini, P. J. Espy, V. Limpasuvan, and R. E. Hibbins Atmos. Chem. Phys. Discuss., 15, 393-413, 2015 AbstractDiscussion Paper (PDF, 1150 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
07 Jan 2015
Signatures of the two day wave and sudden stratospheric warmings in Arctic water vapour observed by ground-based microwave radiometry
Diurnal variations of aerosol optical properties in the North China Plain and their influences on the estimates of direct aerosol radiative forcing
Summary: In this paper, it is found that, the diurnal variations of single scattering albedo (SSA) and asymmetry factor (g) for ambient aerosol are both evident and far different from those of dry state aerosol in the North China Plain (NCP).The diurnal changes of SSA and g have significant impacts on the estimation of daily average direct aerosol radiative forcing (DARF) at the top of the atmosphere. In addition, several suggestions are proposed to improve the accurate prediction of DARF in the NCP.
Enhanced extinction of visible radiation due to hydrated aerosols in mist and fog
T. Elias, J.-C. Dupont, E. Hammer, C. R. Hoyle, M. Haeffelin, F. Burnet, and D. Jolivet Atmos. Chem. Phys. Discuss., 15, 291-337, 2015 AbstractDiscussion Paper (PDF, 1390 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
07 Jan 2015
Advances in understanding mineral dust and boundary layer processes over the Sahara from Fennec aircraft observations
Summary: Measurements of the Saharan atmosphere and of atmospheric mineral dust are lacking but are vital for understanding the climate of this region and its impacts further afield. Novel observations were made by the Fennec climate program during June 2011 and 2012 using ground-based, remote sensing and airborne platforms. Here we describe the airborne observations and the contributions they have made to furthering our understanding of the Saharan climate system.
C. L. Ryder, J. B. McQuaid, C. Flamant, R. Washington, H. E. Brindley, E. J. Highwood, J. H. Marsham, D. J. Parker, M. C. Todd, J. R. Banks, J. K. Brooke, S. Engelstaedter, V. Estellés, P. Formenti, L. Garcia-Carreras, C. Kocha, F. Marenco, P. Rosenberg, H. Sodemann, C. J. T. Allen, A. Bourdon, M. Bart, C. Cavazos-Guerra, S. Chevaillier, J. Crosier, E. Darbyshire, A. R. Dean, J. R. Dorsey, J. Kent, D. O'Sullivan, K. Schepanski, K. Szpek, and A. Woolley Atmos. Chem. Phys. Discuss., 15, 199-290, 2015 AbstractDiscussion Paper (PDF, 6462 KB)Supplement (706 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
07 Jan 2015
Gas and aerosol carbon in California: comparison of measurements and model predictions in Pasadena and Bakersfield
Summary: This work details the evaluation of PM2.5 carbon, VOC precursors, and OH estimated by the CMAQ photochemical transport model using routine and special measurements from the 2010 CalNex field study. Here, CMAQ and most recent emissions inventory (2011 NEI) are used to generate model PM2.5 OC estimates that are examined in novel ways including primary vs. secondary formation, fossil vs. contemporary carbon, OH and HO2 evaluation, and relationship between key VOC precursors and SOC tracers.
K. R. Baker, A. G. Carlton, T. E. Kleindienst, J. H. Offenberg, M. R. Beaver, D. R. Gentner, A. H. Goldstein, P. L. Hayes, J. L. Jimenez, J. B. Gilman, J. A. de Gouw, M. C. Woody, H. O. T. Pye, J. T. Kelly, M. Lewandowski, M. Jaoui, P. S. Stevens, W. H. Brune, Y.-H. Lin, C. L. Rubitschun, and J. D. Surratt Atmos. Chem. Phys. Discuss., 15, 157-198, 2015 AbstractDiscussion Paper (PDF, 2360 KB)Supplement (4067 KB)Interactive Discussion (Open, 3 Comments)Manuscript under review for ACP
07 Jan 2015
High spatial resolution aerosol retrievals used for daily particulate matter monitoring over Po valley, northern Italy
Summary: The manuscript compares 10km Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 5.1 and new 1 km Multi-Angle Implementation of Atmospheric Correction (MAIAC) Aerosol Optical Depth (AOD) retrievals to small (<10 micron) particulate matter (PM10) surface measurements from monitoring stations within the Po Valley in Northern Italy during 2012. When the depth of the planetary boundary layer (PBL) is used to normalize the AOD, we find PM – AOD correlations of 0.98 for both retrievals.
B. Arvani, R. B. Pierce, A. I. Lyapustin, Y. Wang, G. Ghermandi, and S. Teggi Atmos. Chem. Phys. Discuss., 15, 123-155, 2015 AbstractDiscussion Paper (PDF, 3305 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
07 Jan 2015
Quantifying sources, transport, deposition and radiative forcing of black carbon over the Himalayas and Tibetan Plateau
Summary: We use the CAM5 model with a novel source tagging technique to characterize the fate of BC particles emitted from various geographical regions and sectors and their transport pathways to the Himalayas and Tibetan Plateau (HTP). We show a comprehensive picture of the seasonal and regional dependence of BC source attributions, and find strong seasonal and spatial variations of BC-in-snow radiative forcing in HTP that can be quantitatively attributed to the various regional and sectoral sources.
Precipitation effects of giant cloud condensation nuclei artificially introduced into stratocumulus clouds
Summary: To study the effect of giant cloud condensation nuclei (GCCN) on precipitation processes in stratocumulus clouds, 1-10 µm diameter salt particles were released from an aircraft while flying near cloud top off the central coast of California. The analyses suggest that GCCN result in a four-fold increase in the cloud base rainfall rate and depletion of the cloud water due to rainout.
E. Jung, B. A. Albrecht, H. H. Jonsson, Y.-C. Chen, J. H. Seinfeld, A. Sorooshian, A. R. Metcalf, S. Song, M. Fang, and L. M. Russell Atmos. Chem. Phys. Discuss., 15, 47-76, 2015 AbstractDiscussion Paper (PDF, 1085 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACP
07 Jan 2015
Using SEVIRI fire observations to drive smoke plumes in the CMAQ air quality model: the case of Antalya in 2008
Summary: We investigate the quality of fire emission estimates derived from SEVIRI FRP for air quality simulations with the Community Multiscale Air Quality (CMAQ) model, by comparing them with available MODIS FRP based ones.
We demonstrate that geostationary observations allow refining biomass burning emissions, which can subsequently be used in regional scale air quality models in order to improve the prediction of chemical composition of the atmosphere in presence of large fire episodes.
Modeling the formation and aging of secondary organic aerosols in Los Angeles during CalNex 2010
Summary: (1) Four different parameterizations for the formation and chemical evolution of secondary organic aerosol (SOA) are evaluated using a box model representing the Los Angeles Metropolitan Region during the CalNex campaign.
(2) The SOA formed only from the oxidation of VOCs is insufficient to explain the observed SOA concentrations.
(3) The amount of SOA mass formed from diesel vehicle emissions is estimated to be 16-27%.
P. L. Hayes, A. G. Carlton, K. R. Baker, R. Ahmadov, R. A. Washenfelder, S. Alvarez, B. Rappenglück, J. B. Gilman, W. C. Kuster, J. A. de Gouw, P. Zotter, A. S. H. Prévôt, S. Szidat, T. E. Kleindienst, J. H. Offenberg, and J. L. Jimenez Atmos. Chem. Phys. Discuss., 14, 32325-32391, 2014 AbstractDiscussion Paper (PDF, 2055 KB)Supplement (1075 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACP
20 Dec 2014
Using the OMI Aerosol Index and Absorption Aerosol Optical Depth to evaluate the NASA MERRA Aerosol Reanalysis
Summary: MERRAero is an aerosol reanalysis based on the GEOS-5 Earth system model that incorporates an online aerosol module and assimilation of AOD from MODIS sensors.This study assess the quality of MERRAero absorption using independent OMI observations. In addition to comparisons to OMI Absorption AOD, we have developed a radiative transfer interface to simulate the UV Aerosol Index (AI) from assimilated aerosol fields at OMI footprint. Also, we fully diagnose the model using MISR, AERONET and CALIPSO
V. Buchard, A. M. da Silva, P. R. Colarco, A. Darmenov, C. A. Randles, R. Govindaraju, O. Torres, J. Campbell, and R. Spurr Atmos. Chem. Phys. Discuss., 14, 32177-32231, 2014 AbstractDiscussion Paper (PDF, 9370 KB)Supplement (4893 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
19 Dec 2014
Volatile organic compounds over Eastern Himalaya, India: temporal variation and source characterization using Positive Matrix Factorization
C. Sarkar, A. Chatterjee, D. Majumdar, S. K. Ghosh, A. Srivastava, and S. Raha Atmos. Chem. Phys. Discuss., 14, 32133-32175, 2014 AbstractDiscussion Paper (PDF, 2852 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
19 Dec 2014
Formaldehyde (HCHO) in air, snow and interstitial air at Concordia (East Antarctic plateau) in summer
Summary: During two austral summers HCHO was investigated in air, snow, and interstitial air at the Concordia site located on the East Antarctic plateau. Snow emission fluxes were estimated to be around 1 to 2 and 3 to 5 x 1012 molecules m-2 s-1 at night and at noon, respectively. Shading experiments suggest that the photochemical HCHO production in the snowpack at Concordia remains negligible. The mean HCHO level of 130 pptv observed at 1 m above the surface, is quite well reproduced by 1-D simulations.
Particulate emissions from residential wood combustion in Europe – revised estimates and an evaluation
Summary: Residential wood combustion (RWC) is increasing in Europe but may cause high emissions of particulate matter (PM). A new bottom-up emission inventory for RWC was made which included the semi-volatile components. The new RWC emissions are 2-3 times higher than the previous inventory. It significantly improved the modeling of PM and comparison with observations. Our results suggest primary PM2.5 emission from RWC as reported in Europe is underestimated and emission inventories need to be revised.
H. A. C. Denier van der Gon, R. Bergström, C. Fountoukis, C. Johansson, S. N. Pandis, D. Simpson, and A. Visschedijk Atmos. Chem. Phys. Discuss., 14, 31719-31765, 2014 AbstractDiscussion Paper (PDF, 4808 KB)Supplement (346 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACP
16 Dec 2014
A global model simulation for 3-D radiative transfer impact on surface hydrology over Sierra Nevada and Rocky Mountains
Summary: This paper investigates 3-D mountain effects on solar flux distributions and their impact on surface hydrology over the Western United States, specifically the Rocky Mountains and Sierra Nevada using CCSM4 (CAM4/CLM4) global model with a 0.23°×0.31° resolution for simulations over 6 years. We show that deviations of the net surface fluxes are not only affected by 3-D mountains, but also influenced by feedbacks of cloud and snow in association with the long-term simulations.
Evaluation of a regional chemistry transport model using a newly developed regional OMI NO2 retrieval
Summary: Air pollutants can be simulated using models and measured by satellites. We present an improved OMI NO2 retrieval for the Pearl River Delta region which reduces the bias between satellite and ground measurements. The satellite retrieval is used to evaluate a regional air pollution model for which it can form a useful addition to ground measurements. To conclude, we show that our retrieval reduces the bias of satellite measurements which can be very useful for air pollution studies.
On the link between hygroscopicity, volatility, and oxidation state of ambient and water-soluble aerosol in the Southeastern United States
Summary: The hygroscopicity of SE US aerosol is mostly water-soluble, with a hygroscopicity that is insensitive to partial volatilization in a thermodenuder.
The most and least oxidized components of the aerosol are the most hygroscopic of organic constituents.
No clear relationship was found between organic aerosol hygroscopicity and oxygen-to-carbon ratio.
The aerosol factors covary in a way that induces the observed diurnal invariance in total organic hygroscopicity.
K. M. Cerully, A. Bougiatioti, J. R. Hite Jr., H. Guo, L. Xu, N. L. Ng, R. Weber, and A. Nenes Atmos. Chem. Phys. Discuss., 14, 30835-30877, 2014 AbstractDiscussion Paper (PDF, 2782 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACP
09 Dec 2014
Estimates of non-traditional secondary organic aerosols from aircraft SVOC and IVOC emissions using CMAQ
Summary: Utilizing an aircraft-specific parameterization based on smog chamber data in a regional AQM, contributions of non-traditional secondary organic aerosols (NTSOA) from aircraft emissions of semi-volatile and intermediate volatility organic compounds were assessed. NTSOA, a previously unaccounted component of PM2.5 in most AQMs, contributed up to 7.4% of aviation-attributable PM2.5 at the airport, and rose to 17.9% downwind, suggesting its significance in aviation-attributed PM2.5 at all scales.
Evaluating BC and NOx emission inventories for the Paris region from MEGAPOLI aircraft measurements
H. Petetin, M. Beekmann, A. Colomb, H. A. C. Denier van der Gon, J.-C. Dupont, C. Honoré, V. Michoud, Y. Morille, O. Perrussel, A. Schwarzenboeck, J. Sciare, A. Wiedensohler, and Q. J. Zhang Atmos. Chem. Phys. Discuss., 14, 29237-29304, 2014 AbstractDiscussion Paper (PDF, 2711 KB)Supplement (782 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ACPSpecial Issue
24 Nov 2014
Interactions of bromine, chlorine, and iodine photochemistry during ozone depletions in Barrow, Alaska
C. R. Thompson, P. B. Shepson, J. Liao, L. G. Huey, E. C. Apel, C. A. Cantrell, F. Flocke, J. Orlando, A. Fried, S. R. Hall, R. S. Hornbrook, D. J. Knapp, R. L. Mauldin III, D. D. Montzka, B. C. Sive, K. Ullmann, P. Weibring, and A. Weinheimer Atmos. Chem. Phys. Discuss., 14, 28685-28755, 2014 AbstractDiscussion Paper (PDF, 1913 KB)Interactive Discussion (Open, 2 Comments)Manuscript under review for ACP
19 Nov 2014
Long-term (2001–2012) fine particulate matter (PM2.5) and the impact on human health in Beijing, China
Summary: The present study uses Aerosol Optical Depth (AOD) as proxy to estimate 12 years of PM2.5 data for the Beijing central area, and calculate the yearly premature mortality by different diseases attributable to PM2.5. The estimated average total mortality due to PM2.5 is about 6,100 individuals/yr for the period 2001-2012 in the Beijing central area, and for the period 2010-2012 the per capita mortality for all ages due to PM2.5 is around 17.9 per 10,000 person-year.