Articles | Volume 19, issue 19
Research article 08 Oct 2019
Research article | 08 Oct 2019
Multivariate statistical air mass classification for the high-alpine observatory at the Zugspitze Mountain, Germany
Armin Sigmund et al.
Armin Sigmund, Lena Pfister, Chadi Sayde, and Christoph K. Thomas
Atmos. Meas. Tech., 10, 2149–2162,
Karl Lapo, Anita Freundorfer, Antonia Fritz, Johann Schneider, Johannes Olesch, Wolfgang Babel, and Christoph K. Thomas
Earth Syst. Sci. Data Discuss.,
Preprint under review for ESSDShort summary
The layer of air near the surface is poorly understood during conditions with weak winds. Further, it is even difficult to observe. In this experiment we used distributed temperature sensing to observe air temperature and wind speed at 1000 s of points simultaneously every couple of seconds. This incredibly rich data set can be used to examine and understand what drives the mixing between the atmosphere and surface during these weak-wind periods.
Marie-Louise Zeller, Jannis-Michael Huss, Lena Pfister, Karl E. Lapo, Daniela Littmann, Johann Schneider, Alexander Schulz, and Christoph K. Thomas
Earth Syst. Sci. Data Discuss.,
Preprint under review for ESSDShort summary
The Boundary Layer (BL) is well understood when convectively mixed, yet we lack this understanding when it turns stable and no longer follows classic similarity theories. The NYTEFOX campaign collected a unique meteorological data set in the Arctic BL of Svalbard during polar night, where it tends to be highly stable. Using innovative Fiber-Optic Distributed Sensing we are able to provide unique insight into atmospheric motions across large distances resolved continuously in space and time.
Teresa Vogl, Amy Hrdina, and Christoph K. Thomas
Preprint under review for BGShort summary
The Relaxed Eddy Accumulation technique is a method used for measuring fluxes of chemical species in the atmosphere. It relies on a proportionality factor, β, which can be determined using different methods. Also, different techniques for sampling can be used, by only drawing air into the measurement system when vertical wind velocity exceeds a certain threshold. We compare different ways to obtain β and different thresholding techniques to direct flux measurements.
Olli Peltola, Karl Lapo, Ilkka Martinkauppi, Ewan O'Connor, Christoph K. Thomas, and Timo Vesala
Atmos. Meas. Tech. Discuss.,
Revised manuscript accepted for AMTShort summary
We evaluated the suitability of fiber-optic distributed temperature sensing (DTS) to observe spatial (>25 cm) and temporal (>1 s) details of the air flow within and above forests. The DTS measurements were able to discern up to 3rd order moments of the flow and observe spatial details of coherent flow motions. Similar measurements are not possible with more conventional measurement techniques. Hence the DTS measurements will provide key insights into flows close to roughness elements, e.g. trees.
Martine Collaud Coen, Elisabeth Andrews, Andrés Alastuey, Todor Petkov Arsov, John Backman, Benjamin T. Brem, Nicolas Bukowiecki, Cédric Couret, Konstantinos Eleftheriadis, Harald Flentje, Markus Fiebig, Martin Gysel-Beer, Jenny L. Hand, András Hoffer, Rakesh Hooda, Christoph Hueglin, Warren Joubert, Melita Keywood, Jeong Eun Kim, Sang-Woo Kim, Casper Labuschagne, Neng-Huei Lin, Yong Lin, Cathrine Lund Myhre, Krista Luoma, Hassan Lyamani, Angela Marinoni, Olga L. Mayol-Bracero, Nikos Mihalopoulos, Marco Pandolfi, Natalia Prats, Anthony J. Prenni, Jean-Philippe Putaud, Ludwig Ries, Fabienne Reisen, Karine Sellegri, Sangeeta Sharma, Patrick Sheridan, James Patrick Sherman, Junying Sun, Gloria Titos, Elvis Torres, Thomas Tuch, Rolf Weller, Alfred Wiedensohler, Paul Zieger, and Paolo Laj
Atmos. Chem. Phys., 20, 8867–8908,Short summary
Long-term trends of aerosol radiative properties (52 stations) prove that aerosol load has significantly decreased over the last 20 years. Scattering trends are negative in Europe (EU) and North America (NA), not ss in Asia, and show a mix of positive and negative trends at polar stations. Absorption has mainly negative trends. The single scattering albedo has positive trends in Asia and eastern EU and negative in western EU and NA, leading to a global positive median trend of 0.02 % per year.
Jia Sun, Wolfram Birmili, Markus Hermann, Thomas Tuch, Kay Weinhold, Maik Merkel, Fabian Rasch, Thomas Müller, Alexander Schladitz, Susanne Bastian, Gunter Löschau, Josef Cyrys, Jianwei Gu, Harald Flentje, Björn Briel, Christoph Asbach, Heinz Kaminski, Ludwig Ries, Ralf Sohmer, Holger Gerwig, Klaus Wirtz, Frank Meinhardt, Andreas Schwerin, Olaf Bath, Nan Ma, and Alfred Wiedensohler
Atmos. Chem. Phys., 20, 7049–7068,Short summary
To evaluate the effectiveness of emission mitigation policies, we evaluated the trends of the size-resolved particle number concentrations and equivalent black carbon mass concentration at 16 observational sites for various environments in Germany (2009–2018). Overall, significant decrease trends are found for most of the parameters and sites. This study suggests that a combination of emission mitigation policies can effectively improve the air quality on large spatial scales such as in Germany.
Karl Lapo, Anita Freundorfer, Lena Pfister, Johann Schneider, John Selker, and Christoph Thomas
Atmos. Meas. Tech., 13, 1563–1573,Short summary
Most observations of the atmosphere are
point observations, which only measure a small area around the sensor. This limitation creates problems for a number of disciplines, especially those that focus on how the surface and atmosphere exchange heat, mass, and momentum. We used distributed temperature sensing with fiber optics to demonstrate a key breakthrough in observing wind direction in a distributed way, i.e., not at a point, using small structures attached to the fiber-optic cables.
Thomas Trickl, Hannes Vogelmann, Ludwig Ries, and Michael Sprenger
Atmos. Chem. Phys., 20, 243–266,Short summary
Ozone transfer from the stratosphere to the troposphere seems to to have grown over the past decade, parallel to global warming. Lidar measurements, carried out in Garmisch-Partenkirchen, Germany, between 2007 and 2016 show a considerable stratospheric influence in the free troposphere over these sites, with observations of stratospheric layers in the troposphere on 84 % of the measurement days. This high fraction is almost reached also in North America, but frequently not throughout the year.
Martin Schnaiter, Claudia Linke, Inas Ibrahim, Alexei Kiselev, Fritz Waitz, Thomas Leisner, Stefan Norra, and Till Rehm
Atmos. Chem. Phys., 19, 10829–10844,Short summary
When combustion particles are deposited to the ground, they darken Earth's snow and ice surfaces by even tiny quantities. This darkening reduces the back reflection of sunlight and induces an additional climate warming. Particles from fresh snow samples were investigated according to their light absorption strength. Enhanced absorption was found in the snow that cannot fully be attributed to combustion particles. Dust and biogenic matter are likely the cause of this additional snow darkening.
Tobias Linhardt, Joseph S. Levy, and Christoph K. Thomas
The Cryosphere, 13, 2203–2219,Short summary
This study presents surface energy fluxes in an Antarctic polar desert in the summer season, comparing wetted soil at a water track with dominating dry soils. Elevated energy uptake, evaporation, and soil heat fluxes at the water track highlight the importance of wetted soils for water and energy cycling in polar deserts. This connection will grow more relevant, as wetted soils are expected to expand due to climate warming, with implications for landscape-scale hydrology and soil ecosystems.
Anne Klosterhalfen, Alexander Graf, Nicolas Brüggemann, Clemens Drüe, Odilia Esser, María P. González-Dugo, Günther Heinemann, Cor M. J. Jacobs, Matthias Mauder, Arnold F. Moene, Patrizia Ney, Thomas Pütz, Corinna Rebmann, Mario Ramos Rodríguez, Todd M. Scanlon, Marius Schmidt, Rainer Steinbrecher, Christoph K. Thomas, Veronika Valler, Matthias J. Zeeman, and Harry Vereecken
Biogeosciences, 16, 1111–1132,Short summary
To obtain magnitudes of flux components of H2O and CO2 (e.g., transpiration, soil respiration), we applied source partitioning approaches after Scanlon and Kustas (2010) and after Thomas et al. (2008) to high-frequency eddy covariance measurements of 12 study sites covering various ecosystems (croplands, grasslands, and forests) in different climatic regions. We analyzed the interrelations among turbulence, site characteristics, and the performance of both partitioning methods.
Thomas Foken, Wolfgang Babel, and Christoph Thomas
Atmos. Meas. Tech., 12, 971–976,Short summary
Recently reported trends of carbon dioxide uptake pose the question of whether trends may be the result of the limited digitalization of gas analysers and sonic anemometers used in the 1990s. Modifying a 12 bit digitalization and the instrument error reported for the R2 and R3 sonic anemometers found elsewhere, the influence of these deficits in comparison to the now commonly used 16 bit digitalization were quantified. Both issues have an effect only on trace gas fluxes of small magnitude.
Ye Yuan, Ludwig Ries, Hannes Petermeier, Thomas Trickl, Michael Leuchner, Cédric Couret, Ralf Sohmer, Frank Meinhardt, and Annette Menzel
Atmos. Chem. Phys., 19, 999–1012,Short summary
In this study, we presented a time series analysis of a 36-year composite CO2 measurement record at Mount Zugspitze in Germany. Compared with other GAW observatories, Zugspitze proves to be a highly suitable site for monitoring the background levels of air components using proper data selection procedures. Detailed analyses of long-term trends and seasonality, as well as a thorough study of combined weekly periodicity and diurnal cycles, were conducted.
Arlene M. Fiore, Emily V. Fischer, George P. Milly, Shubha Pandey Deolal, Oliver Wild, Daniel A. Jaffe, Johannes Staehelin, Olivia E. Clifton, Dan Bergmann, William Collins, Frank Dentener, Ruth M. Doherty, Bryan N. Duncan, Bernd Fischer, Stefan Gilge, Peter G. Hess, Larry W. Horowitz, Alexandru Lupu, Ian A. MacKenzie, Rokjin Park, Ludwig Ries, Michael G. Sanderson, Martin G. Schultz, Drew T. Shindell, Martin Steinbacher, David S. Stevenson, Sophie Szopa, Christoph Zellweger, and Guang Zeng
Atmos. Chem. Phys., 18, 15345–15361,Short summary
We demonstrate a proof-of-concept approach for applying northern midlatitude mountaintop peroxy acetyl nitrate (PAN) measurements and a multi-model ensemble during April to constrain the influence of continental-scale anthropogenic precursor emissions on PAN. Our findings imply a role for carefully coordinated multi-model ensembles in helping identify observations for discriminating among widely varying (and poorly constrained) model responses of atmospheric constituents to changes in emissions.
Martine Collaud Coen, Elisabeth Andrews, Diego Aliaga, Marcos Andrade, Hristo Angelov, Nicolas Bukowiecki, Marina Ealo, Paulo Fialho, Harald Flentje, A. Gannet Hallar, Rakesh Hooda, Ivo Kalapov, Radovan Krejci, Neng-Huei Lin, Angela Marinoni, Jing Ming, Nhat Anh Nguyen, Marco Pandolfi, Véronique Pont, Ludwig Ries, Sergio Rodríguez, Gerhard Schauer, Karine Sellegri, Sangeeta Sharma, Junying Sun, Peter Tunved, Patricio Velasquez, and Dominique Ruffieux
Atmos. Chem. Phys., 18, 12289–12313,Short summary
High altitude stations are often emphasized as free tropospheric measuring sites but they remain influenced by atmospheric boundary layer. An ABL-TopoIndex is defined from a topography analysis around the stations. This new index allows ranking stations as a function of the ABL influence due to topography or help to choose a new site to sample FT. The ABL-TopoIndex is validated by aerosol optical properties and number concentration measured at 29 high altitude stations of five continents.
Omaira E. García, Matthias Schneider, Benjamin Ertl, Eliezer Sepúlveda, Christian Borger, Christopher Diekmann, Andreas Wiegele, Frank Hase, Sabine Barthlott, Thomas Blumenstock, Uwe Raffalski, Angel Gómez-Peláez, Martin Steinbacher, Ludwig Ries, and Angel M. de Frutos
Atmos. Meas. Tech., 11, 4171–4215,Short summary
This work presents the CH4 and N2O products of the MUSICA IASI processor. We analytically assess precisions of 1.5–3 %, good sensitivity in the UTLS region (for CH4 and N2O) and a possibility for retrieving free-tropospheric CH4 at low latitudes independently from CH4 in the UTLS. This is confirmed by comparison to HIPPO profile data (covering a large latitudinal range), continuous GAW data (covering 9 years) and NDACC FTIR data (covering 10 years and three different climate zones).
Ye Yuan, Ludwig Ries, Hannes Petermeier, Martin Steinbacher, Angel J. Gómez-Peláez, Markus C. Leuenberger, Marcus Schumacher, Thomas Trickl, Cedric Couret, Frank Meinhardt, and Annette Menzel
Atmos. Meas. Tech., 11, 1501–1514,Short summary
This paper presents a novel statistical method, ADVS, for baseline selection of representative CO2 data at elevated mountain measurement stations. It provides insights on how data processing techniques are critical for measurements and data analyses. Compared with other statistical methods, our method appears to be a good option as a generalized approach with improved comparability, which is important for research on measurement site characteristics and comparisons between stations.
Thomas Trickl, Hannes Vogelmann, Ludwig Ries, Hans-Eckhart Scheel, and Michael Sprenger
Atmos. Chem. Phys. Discuss.,
Revised manuscript not accepted
Armin Sigmund, Lena Pfister, Chadi Sayde, and Christoph K. Thomas
Atmos. Meas. Tech., 10, 2149–2162,
Wolfram Birmili, Kay Weinhold, Fabian Rasch, André Sonntag, Jia Sun, Maik Merkel, Alfred Wiedensohler, Susanne Bastian, Alexander Schladitz, Gunter Löschau, Josef Cyrys, Mike Pitz, Jianwei Gu, Thomas Kusch, Harald Flentje, Ulrich Quass, Heinz Kaminski, Thomas A. J. Kuhlbusch, Frank Meinhardt, Andreas Schwerin, Olaf Bath, Ludwig Ries, Holger Gerwig, Klaus Wirtz, and Markus Fiebig
Earth Syst. Sci. Data, 8, 355–382,Short summary
The German Ultraﬁne Aerosol Network (GUAN) provides new continuous data on tropospheric aerosol particles including number size distributions and black carbon. The data are equally relevant for atmospheric studies related to both climate-related and health-related issues. The published data underwent uniform measures of quality assurance and control. The data are available free of charge at the World Data Center for Aerosols EBAS data repository.
Sascha Pfeifer, Thomas Müller, Kay Weinhold, Nadezda Zikova, Sebastiao Martins dos Santos, Angela Marinoni, Oliver F. Bischof, Carsten Kykal, Ludwig Ries, Frank Meinhardt, Pasi Aalto, Nikolaos Mihalopoulos, and Alfred Wiedensohler
Atmos. Meas. Tech., 9, 1545–1551,Short summary
15 aerodynamic particle size spectrometers (APS model 3321, TSI Inc., St. Paul, MN, USA) were compared with a focus on flow rates accuracy, particle sizing, and unit-to-unit variability of the particle number size distribution. Flow rate deviations were relatively small, while the sizing accuracy was found to be within 10 % compared to polystyrene latex reference particles. The unit-to-unit variability in terms of the particle number size distribution during this study was between 10 % and 60 %.
C. Schunk, B. Ruth, M. Leuchner, C. Wastl, and A. Menzel
Nat. Hazards Earth Syst. Sci., 16, 403–415,Short summary
Dead fine fuel (e.g. litter) moisture is a key parameter for wildfire and ecological applications, as it is related to ignitability, fire behavior and soil respiration. For example, fire ignition is highly likely at moisture contents below 10 %, yet nearly impossible above 25 %. Thus, fine fuel moisture measurements are very desirable; however, there is no easy-to-use automated technique available to date. This study investigates the applicability of different sensor types for this measurement.
M. Leuchner, S. Gubo, C. Schunk, C. Wastl, M. Kirchner, A. Menzel, and C. Plass-Dülmer
Atmos. Chem. Phys., 15, 1221–1236,
C. Schunk, C. Wastl, M. Leuchner, C. Schuster, and A. Menzel
Nat. Hazards Earth Syst. Sci., 13, 2157–2167,
Related subject area
Subject: Gases | Research Activity: Field Measurements | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)A mass-weighted isentropic coordinate for mapping chemical tracers and computing atmospheric inventoriesMethane mapping, emission quantification, and attribution in two European cities: Utrecht (NL) and Hamburg (DE)Ozone affected by a succession of four landfall typhoons in the Yangtze River Delta, China: major processes and health impacts4D dispersion of total gaseous mercury derived from a mining source: identification of criteria to assess risks related to high concentrations of atmospheric mercuryEstimating CH4, CO2 and CO emissions from coal mining and industrial activities in the Upper Silesian Coal Basin using an aircraft-based mass balance approachProfiling of formaldehyde, glyoxal, methylglyoxal, and CO over the Amazon: normalized excess mixing ratios and related emission factors in biomass burning plumesSeasonal patterns of atmospheric mercury in tropical South America as inferred by a TGM continuous record at the Chacaltaya Station (5240 m) in BoliviaMeasurement report: Leaf-scale gas exchange of atmospheric reactive trace species (NO2, NO, O3) at a northern hardwood forest in MichiganA dedicated flask sampling strategy developed for Integrated Carbon Observation System (ICOS) stations based on CO2 and CO measurements and Stochastic Time-Inverted Lagrangian Transport (STILT) footprint modellingThe increasing atmospheric burden of the greenhouse gas sulfur hexafluoride (SF6)Understanding nighttime methane signals at the Amazon Tall Tower Observatory (ATTO)Background heterogeneity and other uncertainties in estimating urban methane flux: results from the Indianapolis Flux Experiment (INFLUX)Methane emissions from the Munich OktoberfestA study of the influence of tropospheric subsidence on spring and summer surface ozone concentrations at the JRC Ispra station in northern ItalyLocal and synoptic meteorological influences on daily variability in summertime surface ozone in eastern ChinaVariability in a four-network composite of atmospheric CO2 differences between three primary baseline sitesQuantifying the impact of synoptic circulation patterns on ozone variability in northern China from April to October 2013–2017Evolution of anthropogenic air pollutant emissions in Guangdong Province, China, from 2006 to 2015Speciated atmospheric mercury and sea–air exchange of gaseous mercury in the South China SeaMethane emissions from oil and gas platforms in the North SeaAssessing London CO2, CH4 and CO emissions using aircraft measurements and dispersion modelling2005–2017 ozone trends and potential benefits of local measures as deduced from air quality measurements in the north of the Barcelona metropolitan areaCountry-scale greenhouse gas budgets using shipborne measurements: a case study for the UK and IrelandIntercomparison of midlatitude tropospheric and lower-stratospheric water vapor measurements and comparison to ECMWF humidity dataEddy flux measurements of sulfur dioxide deposition to the sea surfaceQuantifying uncertainties from mobile-laboratory-derived emissions of well pads using inverse Gaussian methodsObserving local CO2 sources using low-cost, near-surface urban monitorsSpatiotemporal variability of NO2 and PM2.5 over Eastern China: observational and model analyses with a novel statistical methodSpatial–temporal patterns of inorganic nitrogen air concentrations and deposition in eastern ChinaPhenomenology of summer ozone episodes over the Madrid Metropolitan Area, central SpainShip-based MAX-DOAS measurements of tropospheric NO2, SO2, and HCHO distribution along the Yangtze RiverGradient flux measurements of sea–air DMS transfer during the Surface Ocean Aerosol Production (SOAP) experimentMeasurements of atmospheric ethene by solar absorption FTIR spectrometryOzone pollution around a coastal region of South China Sea: interaction between marine and continental airAbundance and sources of atmospheric halocarbons in the Eastern MediterraneanDiurnal, synoptic and seasonal variability of atmospheric CO2 in the Paris megacity areaAtmospheric carbonyl sulfide (OCS) measured remotely by FTIR solar absorption spectrometryTemporal variation of VOC fluxes measured with PTR-TOF above a boreal forestLong-term trends of surface ozone and its influencing factors at the Mt Waliguan GAW station, China – Part 2: The roles of anthropogenic emissions and climate variabilityGaseous elemental mercury (GEM) fluxes over canopy of two typical subtropical forests in south ChinaObservations of ozone depletion events in a Finnish boreal forestMobile measurement of methane emissions from natural gas developments in northeastern British Columbia, CanadaImpacts of large-scale circulation on urban ambient concentrations of gaseous elemental mercury in New York, USASurface ozone at Nam Co in the inland Tibetan Plateau: variation, synthesis comparison and 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Yuming Jin, Ralph F. Keeling, Eric J. Morgan, Eric Ray, Nicholas C. Parazoo, and Britton B. Stephens
Atmos. Chem. Phys., 21, 217–238,Short summary
We propose a new atmospheric coordinate (Mθe) based on equivalent potential temperature (θe) but with mass as the unit. This coordinate is useful in studying the spatial and temporal distribution of long-lived chemical tracers (CO2, CH4, O2 / N2, etc.) from sparse data, like airborne observation. Using this coordinate and sparse airborne observation (HIPPO and ATom), we resolve the Northern Hemisphere mass-weighted average CO2 seasonal cycle with high accuracy.
Hossein Maazallahi, Julianne M. Fernandez, Malika Menoud, Daniel Zavala-Araiza, Zachary D. Weller, Stefan Schwietzke, Joseph C. von Fischer, Hugo Denier van der Gon, and Thomas Röckmann
Atmos. Chem. Phys., 20, 14717–14740,Short summary
Methane accounts for ∼ 25 % of current climate warming. The current lack of methane measurements is a barrier for tracking major sources, which are key for near-term climate mitigation. We use mobile measurements to identify and quantify methane emission sources in Utrecht (NL) and Hamburg (DE) with a focus on natural gas pipeline leaks. The measurements resulted in fixing the major leaks by the local utility, but coordinated efforts are needed at national levels for further emission reductions.
Chenchao Zhan, Min Xie, Chongwu Huang, Jane Liu, Tijian Wang, Meng Xu, Chaoqun Ma, Jianwei Yu, Yumeng Jiao, Mengmeng Li, Shu Li, Bingliang Zhuang, Ming Zhao, and Dongyang Nie
Atmos. Chem. Phys., 20, 13781–13799,Short summary
The Yangtze River Delta (YRD) region has been suffering from severe ozone (O3) pollution in recent years. Synoptic systems, like typhoons, can have a significant effect on O3 episodes. However, research on landfall typhoons affecting O3 in the YRD is limited. This work aims to reveal the main processes of landfall typhoons affecting surface O3 and estimate health impacts of O3 during the study period in the YRD, which can be useful for taking reasonable pollution control measures in this area.
José M. Esbrí, Pablo L. Higueras, Alba Martínez-Coronado, and Rocío Naharro
Atmos. Chem. Phys., 20, 12995–13010,Short summary
The aim of this work was to identify criteria to obtain the minimum amount of data with the maximum meaning and representativeness in order to delimit risk areas, both in a spatial and temporal respect. We have constructed a model of vertical mercury movements which could be used to predict the location and timing of mercury inhalation risk. Also, we have designed a monitoring strategy to identify the relevant criteria, which involved the measurement of gaseous mercury in a vertical section.
Alina Fiehn, Julian Kostinek, Maximilian Eckl, Theresa Klausner, Michał Gałkowski, Jinxuan Chen, Christoph Gerbig, Thomas Röckmann, Hossein Maazallahi, Martina Schmidt, Piotr Korbeń, Jarosław Neçki, Pawel Jagoda, Norman Wildmann, Christian Mallaun, Rostyslav Bun, Anna-Leah Nickl, Patrick Jöckel, Andreas Fix, and Anke Roiger
Atmos. Chem. Phys., 20, 12675–12695,Short summary
A severe reduction of greenhouse gas emissions is necessary to fulfill the Paris Agreement. We use aircraft- and ground-based in situ observations of trace gases and wind speed from two flights over the Upper Silesian Coal Basin, Poland, for independent emission estimation. The derived methane emission estimates are within the range of emission inventories, carbon dioxide estimates are in the lower range and carbon monoxide emission estimates are slightly higher than emission inventory values.
Flora Kluge, Tilman Hüneke, Matthias Knecht, Michael Lichtenstern, Meike Rotermund, Hans Schlager, Benjamin Schreiner, and Klaus Pfeilsticker
Atmos. Chem. Phys., 20, 12363–12389,Short summary
The presented study reports on airborne measurements of formaldehyde, glyoxal, methylglyoxal, and CO over the Amazon basin and lays a special focus on the influence of biomass burning emissions on the atmospheric profiles of these carbonyl compounds within the planetary boundary layer as well as in the free and upper troposphere.
Alkuin Maximilian Koenig, Olivier Magand, Paolo Laj, Marcos Andrade, Isabel Moreno, Fernando Velarde, Grover Salvatierra, René Gutierrez, Luis Blacutt, Diego Aliaga, Thomas Reichler, Karine Sellegri, Olivier Laurent, Michel Ramonet, and Aurélien Dommergue
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
The environmental cycling of atmospheric mercury, a harmful global contaminant, is still not sufficiently constrained, partly due to missing data in remote regions. Here, we address this issue by presenting 20 months of atmospheric mercury measurements, sampled in the Bolivian Andes. We observe a significant seasonal pattern, whose key features we explore. Moreover, we deduce ratios to constrain South American biomass burning mercury emissions and the mercury uptake by the Amazon rainforest.
Wei Wang, Laurens Ganzeveld, Samuel Rossabi, Jacques Hueber, and Detlev Helmig
Atmos. Chem. Phys., 20, 11287–11304,Short summary
Trees exchange with the atmosphere nitrogen oxides and ozone, affecting the tropospheric composition and consequently air quality and ecosystem health. We examined the leaf-level gas exchanges for four typical tree species (pine, maple, oak, aspen) found in northern Michigan, US. The leaves largely absorb the gases, showing little evidence of emission. We measured the uptake rates that can be used to improve model studies of the source and sink processes controlling these gases in forests.
Ingeborg Levin, Ute Karstens, Markus Eritt, Fabian Maier, Sabrina Arnold, Daniel Rzesanke, Samuel Hammer, Michel Ramonet, Gabriela Vítková, Sebastien Conil, Michal Heliasz, Dagmar Kubistin, and Matthias Lindauer
Atmos. Chem. Phys., 20, 11161–11180,Short summary
Based on observations and Stochastic Time-Inverted Lagrangian Transport (STILT) footprint modelling, a sampling strategy has been developed for tall tower stations of the Integrated Carbon Observation System (ICOS) research infrastructure atmospheric station network. This strategy allows independent quality control of in situ measurements, provides representative coverage of the influence area of the sites, and is capable of automated targeted sampling of fossil fuel CO2 emission hotspots.
Peter G. Simmonds, Matthew Rigby, Alistair J. Manning, Sunyoung Park, Kieran M. Stanley, Archie McCulloch, Stephan Henne, Francesco Graziosi, Michela Maione, Jgor Arduini, Stefan Reimann, Martin K. Vollmer, Jens Mühle, Simon O'Doherty, Dickon Young, Paul B. Krummel, Paul J. Fraser, Ray F. Weiss, Peter K. Salameh, Christina M. Harth, Mi-Kyung Park, Hyeri Park, Tim Arnold, Chris Rennick, L. Paul Steele, Blagoj Mitrevski, Ray H. J. Wang, and Ronald G. Prinn
Atmos. Chem. Phys., 20, 7271–7290,Short summary
Sulfur hexafluoride (SF6) is a potent greenhouse gas which is regulated under the Kyoto Protocol. From a 40-year record of measurements, collected at five global monitoring sites and archived air samples, we show that its concentration in the atmosphere has steadily increased. Using modelling techniques, we estimate that global emissions have increased by about 24 % over the past decade. We find that this increase is driven by the demand for SF6-insulated switchgear in developing countries.
Santiago Botía, Christoph Gerbig, Julia Marshall, Jost V. Lavric, David Walter, Christopher Pöhlker, Bruna Holanda, Gilberto Fisch, Alessandro Carioca de Araújo, Marta O. Sá, Paulo R. Teixeira, Angélica F. Resende, Cleo Q. Dias-Junior, Hella van Asperen, Pablo S. Oliveira, Michel Stefanello, and Otávio C. Acevedo
Atmos. Chem. Phys., 20, 6583–6606,Short summary
A long record of atmospheric methane concentrations in central Amazonia was analyzed. We describe events in which concentrations at 79 m are higher than at 4 m. These events are more frequent during the nighttime of dry season, but we found no association with fire signals. Instead, we suggest that a combination of nighttime transport and a nearby source could explain such events. Our research gives insights into how methane is transported in the complex nocturnal atmosphere in Amazonia.
Nikolay V. Balashov, Kenneth J. Davis, Natasha L. Miles, Thomas Lauvaux, Scott J. Richardson, Zachary R. Barkley, and Timothy A. Bonin
Atmos. Chem. Phys., 20, 4545–4559,Short summary
An accurate independent verification methodology to estimate methane (a powerful greenhouse gas) emissions is essential for the effective implementation of policies that aim to reduce the impacts of climate change. In this paper, four uncertainties that complicate the independent estimation of urban methane emissions are identified: the definition of urban domain, background heterogeneity, emissions temporal variability, and missing sources. Ways to improve emission estimates are suggested.
Jia Chen, Florian Dietrich, Hossein Maazallahi, Andreas Forstmaier, Dominik Winkler, Magdalena E. G. Hofmann, Hugo Denier van der Gon, and Thomas Röckmann
Atmos. Chem. Phys., 20, 3683–3696,Short summary
We demonstrate for the first time that large festivals can be significant methane sources, though they are not included in emission inventories. We combined in situ measurements with a Gaussian plume model to determine the Oktoberfest emissions and show that they are not due solely to human biogenic emissions, but are instead primarily fossil fuel related. Our study provides the foundation to develop reduction policies for such events and new pathways to mitigate fossil fuel methane emissions.
Pavlos Kalabokas, Niels Roland Jensen, Mauro Roveri, Jens Hjorth, Maxim Eremenko, Juan Cuesta, Gaëlle Dufour, Gilles Foret, and Matthias Beekmann
Atmos. Chem. Phys., 20, 1861–1885,Short summary
The influence of tropospheric ozone on the surface measurements at a regional air pollution station in the pre-Alpine area of northern Italy is investigated. During such episodes the local air pollution parameters show generally very low values, while the ozone levels reach high values, occasionally exceeding the ozone air quality standards. Better understanding of ozone variability over the examined region will help in the formulation of more effective policies for the environment and climate.
Han Han, Jane Liu, Lei Shu, Tijian Wang, and Huiling Yuan
Atmos. Chem. Phys., 20, 203–222,Short summary
We statistically assessed the impacts of local and synoptic meteorology on daily surface ozone in eastern China in summer during 2013–2018. The results show that the meteorology described by a multiple linear regression model explains 43 % of variations in surface ozone. The most important local meteorological factors vary with location in eastern China. The maximum impact of the predominant synoptic pattern on surface ozone can reach ± 8 µg m-3 or ± 16 % of the daily mean over some regions.
Roger J. Francey, Jorgen S. Frederiksen, L. Paul Steele, and Ray L. Langenfelds
Atmos. Chem. Phys., 19, 14741–14754,Short summary
25-year composites of interhemispheric baseline CO2 differences demonstrate close agreement between 4 monitoring networks. Variability from monthly to multiyear time frames mostly reflects variability in upper troposphere dynamical indices chosen to represent eddy and mean transport interhemispheric exchange. Monthly interhemispheric atmospheric fluxes are much larger than air–surface terrestrial exchanges. The composite differences offer unusual constraints on transport in global carbon models.
Jingda Liu, Lili Wang, Mingge Li, Zhiheng Liao, Yang Sun, Tao Song, Wenkang Gao, Yonghong Wang, Yan Li, Dongsheng Ji, Bo Hu, Veli-Matti Kerminen, Yuesi Wang, and Markku Kulmala
Atmos. Chem. Phys., 19, 14477–14492,Short summary
We analyzed the surface ozone variation characteristics and quantified the impact of synoptic and local meteorological factors on northern China during the warm season based on multi-city, in situ ozone and meteorological data, as well as meteorological reanalysis. The results of quantitative exploration on synoptic and local meteorological factors influencing both interannual and day-to-day ozone variations will provide the scientific basis for evaluating emission reduction measures.
Yahui Bian, Zhijiong Huang, Jiamin Ou, Zhuangmin Zhong, Yuanqian Xu, Zhiwei Zhang, Xiao Xiao, Xiao Ye, Yuqi Wu, Xiaohong Yin, Cheng Li, Liangfu Chen, Min Shao, and Junyu Zheng
Atmos. Chem. Phys., 19, 11701–11719,Short summary
During 2006–2015, emissions of SO2, NOx, PM2.5 and PM10 saw an obvious downtrend. However, most emissions still have large reduction potential. On-road mobile sources and solvent use are the two key sources that should receive more effective control measures in GD. Also, controls measures on VOC and NH3 should be weighted since they still increased in 2006–2015. Since most control measures focused on PRD rather than non-PRD in GD, emissions in non-PRD were increasingly important.
Chunjie Wang, Zhangwei Wang, Fan Hui, and Xiaoshan Zhang
Atmos. Chem. Phys., 19, 10111–10127,Short summary
A low GEM level indicated that the SCS suffered less anthropogenic influence. There was no significant difference in GEM and HgP2.5 values between day and night, but the RGM level was higher in daytime than in nighttime. The size distribution of HgP in PM10 was observed to be bi-modal, but the coarse modal was the dominant size. The annual emission flux of Hg0 from the SCS was estimated to be 159 ton yr-1. The dry deposition was an important pathway for the input of atmospheric Hg to the SCS.
Stuart N. Riddick, Denise L. Mauzerall, Michael Celia, Neil R. P. Harris, Grant Allen, Joseph Pitt, John Staunton-Sykes, Grant L. Forster, Mary Kang, David Lowry, Euan G. Nisbet, and Alistair J. Manning
Atmos. Chem. Phys., 19, 9787–9796,Short summary
Currently, bottom-up methods estimate that 0.13 % of methane produced by UK North Sea oil and gas installations is lost. Here we measure emissions from eight platforms in the North Sea and, when considered collectively, the methane loss is estimated at 0.19 % of gas production. As this ambient loss is not explicitly accounted for in the bottom-up approach, these measured emissions represent significant additional emissions above previous estimates.
Joseph R. Pitt, Grant Allen, Stéphane J.-B. Bauguitte, Martin W. Gallagher, James D. Lee, Will Drysdale, Beth Nelson, Alistair J. Manning, and Paul I. Palmer
Atmos. Chem. Phys., 19, 8931–8945,Short summary
This paper presents a new method to assess inventory estimates of greenhouse gas and air pollutant emissions for large cities and their surrounding regions. A case study using data sampled by a research aircraft around London was used to test the method. We found that the UK national inventory agrees with our observations for CO but needed lower emissions for CH4 to agree with the measured data. Repeated studies could help determine how these emissions vary on different timescales.
Jordi Massagué, Cristina Carnerero, Miguel Escudero, José María Baldasano, Andrés Alastuey, and Xavier Querol
Atmos. Chem. Phys., 19, 7445–7465,
Carole Helfter, Neil Mullinger, Massimo Vieno, Simon O'Doherty, Michel Ramonet, Paul I. Palmer, and Eiko Nemitz
Atmos. Chem. Phys., 19, 3043–3063,Short summary
We present a novel approach to estimate the annual budgets of carbon dioxide (881.0 ± 128.5 Tg) and methane (2.55 ± 0.48 Tg) of the British Isles from shipborne measurements taken over a 3-year period (2015–2017). This study brings independent verification of the emission budgets estimated using alternative products and investigates the seasonality of these emissions, which is usually not possible.
Stefan Kaufmann, Christiane Voigt, Romy Heller, Tina Jurkat-Witschas, Martina Krämer, Christian Rolf, Martin Zöger, Andreas Giez, Bernhard Buchholz, Volker Ebert, Troy Thornberry, and Ulrich Schumann
Atmos. Chem. Phys., 18, 16729–16745,Short summary
We present an intercomparison of the airborne water vapor measurements during the ML-CIRRUS mission. Although the agreement of the hygrometers significantly improved compared to studies from recent decades, systematic differences remain under specific meteorological conditions. We compare the measurements to model data, where we observe a model wet bias in the lower stratosphere close to the tropopause, likely caused by a blurred humidity gradient in the model tropopause.
Jack G. Porter, Warren De Bruyn, and Eric S. Saltzman
Atmos. Chem. Phys., 18, 15291–15305,Short summary
Deposition to the sea surface is a major loss pathway for highly soluble atmospheric trace gases. These fluxes are important to biogeochemical cycles, climate, and air quality. Here we report measurements of air–sea fluxes of sulfur dioxide, sensible heat, and momentum to coastal waters. Transfer velocities derived from the data show a dependence on molecular diffusivity, demonstrating the importance of diffusion in the interfacial layer on the atmospheric side of the air–sea interface.
Dana R. Caulton, Qi Li, Elie Bou-Zeid, Jeffrey P. Fitts, Levi M. Golston, Da Pan, Jessica Lu, Haley M. Lane, Bernhard Buchholz, Xuehui Guo, James McSpiritt, Lars Wendt, and Mark A. Zondlo
Atmos. Chem. Phys., 18, 15145–15168,Short summary
Mobile laboratory measurements have been widely used to quantify methane emissions from point sources such as oil and gas wells, but the emission uncertainties are poorly constrained. We designed a hierarchical measurement strategy to sample natural gas emissions in the Marcellus Shale play based upon high-resolution modeling of select sites. Our study quantifies the largest sources of error with this approach and provides guidance on how to best implement mobile laboratory sampling protocols.
Alexis A. Shusterman, Jinsol Kim, Kaitlyn J. Lieschke, Catherine Newman, Paul J. Wooldridge, and Ronald C. Cohen
Atmos. Chem. Phys., 18, 13773–13785,Short summary
We describe the diversity and heterogeneity of urban CO2 levels observed using the BErkeley Atmospheric CO2 Observation Network, a distributed instrument of > 50 CO2 sensors stationed every ~ 2 km across the San Francisco Bay Area. We demonstrate that relatively simple mathematical techniques, applied to these observations, can be used to detect the small changes in highway CO2 emissions expected to result from upcoming fuel economy regulations, affirming the policy relevance of low-cost sensors.
Mengyao Liu, Jintai Lin, Yuchen Wang, Yang Sun, Bo Zheng, Jingyuan Shao, Lulu Chen, Yixuan Zheng, Jinxuan Chen, Tzung-May Fu, Yingying Yan, Qiang Zhang, and Zhaohua Wu
Atmos. Chem. Phys., 18, 12933–12952,Short summary
Eastern China is heavily polluted by NO2, PM2.5, and other air pollutants. Our study uses EOF–EEMD to analyze the spatiotemporal variability of ground-level NO2, PM2.5, and their associations with meteorological processes. Their regular diurnal cycles are mainly affected by human activities, while irregular day-to-day variations are dominated by weather processes representing synchronous variation or north–south opposing changes over Eastern China.
Wen Xu, Lei Liu, Miaomiao Cheng, Yuanhong Zhao, Lin Zhang, Yuepeng Pan, Xiuming Zhang, Baojing Gu, Yi Li, Xiuying Zhang, Jianlin Shen, Li Lu, Xiaosheng Luo, Yu Zhao, Zhaozhong Feng, Jeffrey L. Collett Jr., Fusuo Zhang, and Xuejun Liu
Atmos. Chem. Phys., 18, 10931–10954,Short summary
Our main results demonstrate that atmospheric Nr pollution in eastern China is more serious in the northern region than in the southern region. Any effects of current emission controls are not yet apparent in Nr pollution. NH3 emissions from fertilizer use were the largest contributor (36 %) to total inorganic Nr deposition. Our results provide useful information for policy-makers that mitigation of NH3 emissions should be a priority to tackle serious N deposition.
Xavier Querol, Andrés Alastuey, Gotzon Gangoiti, Noemí Perez, Hong K. Lee, Heeram R. Eun, Yonghee Park, Enrique Mantilla, Miguel Escudero, Gloria Titos, Lucio Alonso, Brice Temime-Roussel, Nicolas Marchand, Juan R. Moreta, M. Arantxa Revuelta, Pedro Salvador, Begoña Artíñano, Saúl García dos Santos, Mónica Anguas, Alberto Notario, Alfonso Saiz-Lopez, Roy M. Harrison, Millán Millán, and Kang-Ho Ahn
Atmos. Chem. Phys., 18, 6511–6533,Short summary
We show the main drivers of high O3 episodes in and around Madrid. High levels of ultrafine particles (UFPs) are evidenced, but we demonstrate that most O3 arises from the fumigation of high atmospheric layers, whereas UFPs are generated inside the PBL. O3 contributions from the fumigation of the vertical recirculation of regional air masses, hemispheric transport, and horizontally from direct urban plume transport are shown. Complexity arises from the need to quantify them to abate surface O3.
Qianqian Hong, Cheng Liu, Ka Lok Chan, Qihou Hu, Zhouqing Xie, Haoran Liu, Fuqi Si, and Jianguo Liu
Atmos. Chem. Phys., 18, 5931–5951,Short summary
We presented ship-based MAX-DOAS measurements of tropospheric trace gases' distribution along the eastern part of the Yangtze River during winter 2015. Tropospheric VCDs of NO2, SO2, and HCHO were retrieved from MAX-DOAS measurement spectra. Enhanced tropospheric NO2 and SO2 VCDs were detected over downwind areas of industrial zones over the Yangtze River. Our results indicate that different pollution control strategies should be applied in different provinces.
Murray J. Smith, Carolyn F. Walker, Thomas G. Bell, Mike J. Harvey, Eric S. Saltzman, and Cliff S. Law
Atmos. Chem. Phys., 18, 5861–5877,Short summary
The transfer of gases across the air–sea interface has a significant influence on climate. During a research voyage in the South Pacific we measured the transfer rate of the biogenic gas dimethyl sulfide (DMS) from the ocean using two independent methods. The agreement between the techniques provides confidence in their use in compilations of global gas transfer. We also identified physical conditions under which the observations are not well predicted by a standard gas transfer model.
Geoffrey C. Toon, Jean-Francois L. Blavier, and Keeyoon Sung
Atmos. Chem. Phys., 18, 5075–5088,Short summary
Remote sensing measurements of ethene have been made from the ground and from balloons. Ethene can be measured at low altitudes in polluted regions, such as the Los Angeles basin. Here ethene amounts have decreased by a factor of 3 over the past 25 years due to increasingly strict emission control regulations (e.g., on vehicle exhaust).
Hao Wang, Xiaopu Lyu, Hai Guo, Yu Wang, Shichun Zou, Zhenhao Ling, Xinming Wang, Fei Jiang, Yangzong Zeren, Wenzhuo Pan, Xiaobo Huang, and Jin Shen
Atmos. Chem. Phys., 18, 4277–4295,Short summary
While oceanic air is generally thought to be clean, the air pollution over waters in proximity to the coasts is not well recognized. This research indicated that ozone was higher over South China Sea (SCS) than that in the adjacent continental area, while continental anticyclone, tropical cyclone and land breeze favored O3 formation over SCS. In addition, weaker NO titration and stronger atmospheric oxidative capacity led to higher O3 production efficiency over SCS.
Fabian Schoenenberger, Stephan Henne, Matthias Hill, Martin K. Vollmer, Giorgos Kouvarakis, Nikolaos Mihalopoulos, Simon O'Doherty, Michela Maione, Lukas Emmenegger, Thomas Peter, and Stefan Reimann
Atmos. Chem. Phys., 18, 4069–4092,Short summary
Anthropogenic halocarbon emissions contribute to stratospheric ozone depletion and global warming. We measured atmospheric halocarbons for 6 months on Crete to extend the coverage of the existing observation network to the Eastern Mediterranean. The derived emission estimates showed a contribution of 16.8 % (13.6–23.3 %) and 53.2 % (38.1–84.2 %) of this region to the total HFC and HCFC emissions of the analyzed European domain and a reduction of the underlying uncertainties by 40–80 %.
Irène Xueref-Remy, Elsa Dieudonné, Cyrille Vuillemin, Morgan Lopez, Christine Lac, Martina Schmidt, Marc Delmotte, Frédéric Chevallier, François Ravetta, Olivier Perrussel, Philippe Ciais, François-Marie Bréon, Grégoire Broquet, Michel Ramonet, T. Gerard Spain, and Christophe Ampe
Atmos. Chem. Phys., 18, 3335–3362,Short summary
Urbanized and industrialized areas are the largest source of fossil CO2. This work analyses the atmospheric CO2 variability observed from the first in situ network deployed in the Paris megacity area. Gradients of several ppm are found between the rural, peri-urban and urban sites at the diurnal to the seasonal scales. Wind direction and speed as well as boundary layer dynamics, correlated to highly variable urban emissions, are shown to be key regulator factors of the observed CO2 records.
Geoffrey C. Toon, Jean-Francois L. Blavier, and Keeyoon Sung
Atmos. Chem. Phys., 18, 1923–1944,Short summary
OCS is the main form of atmospheric sulfur. It is produced near the earth's surface and destroyed primarily in the stratosphere, where it is converted to stratospheric sulfate aerosol (SSA). SSA plays an important role in atmospheric chemistry and transport and so it is important to better understand the factors that regulate OCS and hence SSA. Ground-based and balloon-borne infrared spectra observed over the past 30 years are analyzed to provide an improved OCS dataset.
Simon Schallhart, Pekka Rantala, Maija K. Kajos, Juho Aalto, Ivan Mammarella, Taina M. Ruuskanen, and Markku Kulmala
Atmos. Chem. Phys., 18, 815–832,Short summary
Emissions of volatile organic compounds (VOCs) have impact to air quality, human health and climate. We investigated the development of VOC exchange in a boreal forest between April and June 2013. VOC exchange and diversity increased towards summer, but over 75 % of the biogenic net exchange was driven by methanol, monoterpenes and acetone only. The boreal forest emitted less than 0.2 % carbon in form of VOCs in relation to the carbon uptake.
Wanyun Xu, Xiaobin Xu, Meiyun Lin, Weili Lin, David Tarasick, Jie Tang, Jianzhong Ma, and Xiangdong Zheng
Atmos. Chem. Phys., 18, 773–798,Short summary
The impact of anthropogenic emissions and climate variability on the long-term trends and periodicity of surface ozone measured at Mt Waliguan (WLG) for the period of 1994–2013 is studied. STT ozone and rising emissions in eastern China contribute to spring and autumnal increasing trends, respectively. The 2–3-, 3–7-, and 11-year periodicities in the ozone data are linked to the QBO, EASMI, and sunspot cycle, respectively. An empirical model is obtained for normalised monthly ozone at WLG.
Qian Yu, Yao Luo, Shuxiao Wang, Zhiqi Wang, Jiming Hao, and Lei Duan
Atmos. Chem. Phys., 18, 495–509,Short summary
This study provides high-quality direct observation data of a clean and a contaminated site in subtropical south China and quantifies the natural forest Hg emission. We find that clean and contaminated forests present a net GEM source with annual average values of 6.67 and 0.30 ng m-2 h-1, respectively; daily variations of GEM fluxes showed a source in the daytime with a peak at 13:00, and as a sink or balance at night; and higher atmospheric GEM concentration restricted the forest GEM emission.
Xuemeng Chen, Lauriane L. J. Quéléver, Pak L. Fung, Jutta Kesti, Matti P. Rissanen, Jaana Bäck, Petri Keronen, Heikki Junninen, Tuukka Petäjä, Veli-Matti Kerminen, and Markku Kulmala
Atmos. Chem. Phys., 18, 49–63,Short summary
We analysed a 20-year-long dataset collected in a Finnish boreal forest at SMEAR II station to investigate the frequency and strength of ozone depletion events. We could identify a number of ozone depletion events that lasted for more than 3 h, mainly in the autumn and winter months. Their occurrence was likely related to the formation of a low mixing layer under the conditions of low temperatures, low wind speeds, high relative humidities and limited intensity of solar radiation.
Emmaline Atherton, David Risk, Chelsea Fougère, Martin Lavoie, Alex Marshall, John Werring, James P. Williams, and Christina Minions
Atmos. Chem. Phys., 17, 12405–12420,Short summary
Methane is a potent greenhouse gas, and leaks from natural gas infrastructure are thought to be a significant emission source. We used a mobile survey method to measure GHGs near Canadian infrastructure. Our results show that ~ 47 % of active wells were emitting. Abandoned and aging wells were also associated with emissions. We estimate methane emissions from this development are just over 111 Mt year−1, which is more than previous government estimates, but less than similar studies in the US.
Huiting Mao, Dolly Hall, Zhuyun Ye, Ying Zhou, Dirk Felton, and Leiming Zhang
Atmos. Chem. Phys., 17, 11655–11671,Short summary
Mercury (Hg) is a global pollutant hazardous to human and ecosystem health, and its emission control is imperative. Anthropogenic mercury emissions have been reduced by 78 % in the United States from 1990 to 2014. However, no clearly defined trend was observed in Hg concentrations at urban locations such as the one in this study. This indicates that other factors may have dominated over anthropogenic emission control. The implications of this study could hence be highly policy relevant.
Xiufeng Yin, Shichang Kang, Benjamin de Foy, Zhiyuan Cong, Jiali Luo, Lang Zhang, Yaoming Ma, Guoshuai Zhang, Dipesh Rupakheti, and Qianggong Zhang
Atmos. Chem. Phys., 17, 11293–11311,Short summary
We presented 5-year surface ozone measurements at Nam Co in the inland Tibetan Plateau and made a synthesis comparison of diurnal and seasonal patterns on regional and hemispheric scales. Surface ozone at Nam Co is mainly dominated by natural processes and is less influenced by stratospheric intrusions and human activities than on the rim of the Tibetan Plateau. Ozone at Nam Co is representative of background that is valuable for studying ozone-related effects on large scales.
Bo Christiansen, Nis Jepsen, Rigel Kivi, Georg Hansen, Niels Larsen, and Ulrik Smith Korsholm
Atmos. Chem. Phys., 17, 9347–9364,Short summary
Ozone soundings in the troposphere from nine Arctic stations covering the period 1984–2014 have been analyzed. Stations with the best data coverage show a consistent and significant temporal variation with a maximum near 2005 followed by a decrease. Some significant changes are found in the annual cycle in agreement with the notion that the ozone summer maximum is appearing earlier in the year. Such changes in Arctic ozone in the free troposphere have not been reported before.
Thomas G. Bell, Sebastian Landwehr, Scott D. Miller, Warren J. de Bruyn, Adrian H. Callaghan, Brian Scanlon, Brian Ward, Mingxi Yang, and Eric S. Saltzman
Atmos. Chem. Phys., 17, 9019–9033,Short summary
The mechanisms that determine the air–sea exchange of gases such as carbon dioxide are not well understood. During a research cruise in the North Atlantic, we simultaneously measured the air–sea transfer of two gases with contrasting solubility over a range in wind and wave conditions. We compare the transfer of these gases to improve understanding of how bubbles from breaking waves may mediate air–sea gas fluxes.
Stuart N. Riddick, Sarah Connors, Andrew D. Robinson, Alistair J. Manning, Pippa S. D. Jones, David Lowry, Euan Nisbet, Robert L. Skelton, Grant Allen, Joseph Pitt, and Neil R. P. Harris
Atmos. Chem. Phys., 17, 7839–7851,Short summary
High methane mixing ratios occurred at our long-term measurement site. Isotopic measurements show the source is a landfill 7 km away; the emissions were estimated using three different approaches. The emission estimates made by near-source and middle-distance methods agree well for a period of intense observation. The estimate of the inverse modelling is similar to the labour-intensive middle-distance approach, which shows it can be used to identify point sources within an emission landscape.
Philippe Ricaud, Eric Bazile, Massimo del Guasta, Christian Lanconelli, Paolo Grigioni, and Achraf Mahjoub
Atmos. Chem. Phys., 17, 5221–5237,Short summary
The novelty of the paper is to combine a large set of measurements and meteorological models to study the genesis of thick cloud and diamond dust/ice fog (ice crystals) episodes above Dome C, Antarctica. The originality of the work is to attribute the presence of thick cloud and diamond dust/ice fog to advection and microphysical processes with oceanic and continental origin of air masses, respectively. Thick cloud episodes are reproduced by the models but not diamond dust/ice fog episode.
Dan Li, Bärbel Vogel, Jianchun Bian, Rolf Müller, Laura L. Pan, Gebhard Günther, Zhixuan Bai, Qian Li, Jinqiang Zhang, Qiujun Fan, and Holger Vömel
Atmos. Chem. Phys., 17, 4657–4672,Short summary
High-resolution ozone and water vapour profiles over Lhasa, China, were measured in August 2013. The correlations between ozone and water vapour profiles show a strong variability in the upper troposphere. These relationships were investigated using CLaMS trajectory calculations. The model results demonstrate that three tropical cyclones (Jebi, Utor, and Trami), occurring over the western Pacific, had a strong impact on the vertical structure of ozone and water vapour profiles.
Pavlos Kalabokas, Jens Hjorth, Gilles Foret, Gaëlle Dufour, Maxim Eremenko, Guillaume Siour, Juan Cuesta, and Matthias Beekmann
Atmos. Chem. Phys., 17, 3905–3928,Short summary
The main atmospheric mechanisms linked with spring surface ozone episodes over the western Mediterranean are examined. It comes out that high surface midday ozone values are usually linked with regional ozone episodes, which are strongly influenced by some specific meteorological conditions. The better understanding of the ozone variability in the lower troposphere and the boundary layer over the examined regions will help in the formulation of more effective policies in environment and climate.
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Air masses at the Schneefernerhaus mountain site at Zugspitze Mountain, Germany, were classified with respect to the atmospheric layer from which they originated and their degree of pollution. Measurements of several gases, particulate matter, and standard meteorological quantities indicated that polluted air was lifted to the site in 31 % of cases and clean air descended to the site in approximately 14 % cases while most of the remaining cases were ambiguous.
Air masses at the Schneefernerhaus mountain site at Zugspitze Mountain, Germany, were classified...