Payday loans
Home Publications Journal Publications

Journal Publications

This section contains all refereed journal publications that have some connection either with the Mace Head Research Station or with members, both present and past, of the Atmospheric Physics Research Cluster at NUI, Galway.

Click on the "Search Document" icon above to find a publication based on the search criteria you create.

 


Documents

Order by : Name | Date | Hits | [ Ascendant ]

Particle mobility size spectrometers: harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions Particle mobility size spectrometers: harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions

Date added: 03/19/2013
Date modified: 03/19/2013
Filesize: 1021.65 kB

Wiedensohler, A., Birmili, W., Nowak, A., Sonntag, A., Weinhold, K., Merkel, M., Wehner, B., Tuch, T., Pfeifer, S., Fiebig, M., Fjäraa, A. M., Asmi, E., Sellegri, K., Depuy, R., Venzac, H., Villani, P., Laj, P., Aalto, P., Ogren, J. A., Swietlicki, E., Roldin, P., Williams, P., Quincey, P., Hüglin, C., Fierz-Schmidhauser, R., Gysel, M., Weingartner, E., Riccobono, F., Santos, S., Grüning, C., Faloon, K., Beddows, D., Harrison, R. M., Monahan, C., Jennings, S. G., O'Dowd, C. D., Marinoni, A., Horn, H.-G., Keck, L., Jiang, J., Scheckman, J., McMurry, P. H., Deng, Z., Zhao, C. S., Moerman, M., Henzing, B., and de Leeuw, G.: Particle mobility size spectrometers: harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions, Atmos. Meas. Techs., Vol 5 Issue 3 Pages 657-685 DOI: 10.5194/amt-5-657-2012,2012.


Abstract. Mobility particle size spectrometers often referred to as DMPS (Differential Mobility Particle Sizers) or SMPS (Scanning Mobility Particle Sizers) have found a wide range of applications in atmospheric aerosol research. However, comparability of measurements conducted world-wide is hampered by lack of generally accepted technical standards and guidelines with respect to the instrumental setup, measurement mode, data evaluation as well as quality control. Technical standards were developed for a minimum requirement of mobility size spectrometry to perform long-term atmospheric aerosol measurements. Technical recommendations include continuous monitoring of flow rates, temperature, pressure, and relative humidity for the sheath and sample air in the differential mobility analyzer. We compared commercial and custom-made inversion routines to calculate the particle number size distributions from the measured electrical mobility distribution. All inversion routines are comparable within few per cent uncertainty for a given set of raw data. Furthermore, this work summarizes the results from several instrument intercomparison workshops conducted within the European infrastructure project EUSAAR (European Supersites for Atmospheric Aerosol Research) and ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network) to determine present uncertainties especially of custom-built mobility particle size spectrometers. Under controlled laboratory conditions, the particle number size distributions from 20 to 200 nm determined by mobility particle size spectrometers of different design are within an uncertainty range of around ±10% after correcting internal particle losses, while below and above this size range the discrepancies increased. For particles larger than 200 nm, the uncertainty range increased to 30 %, which could not be explained. The network reference mobility spectrometers with identical design agreed within ±4% in the peak particle number concentration when all settings were done carefully. The consistency of these reference instruments to the total particle number concentration was demonstrated to be less than 5 %. Additionally, a new data structure for particle number size distributions was introduced to store and disseminate the data at EMEP (European Monitoring and Evaluation Program). This structure contains three levels: raw data, processed data, and final particle size distributions. Importantly, we recommend reporting raw measurements including all relevant instrument parameters as well as a complete documentation on all data transformation and correction steps. These technical and data structure standards aim to enhance the quality of long-term size distribution measurements, their comparability between different networks and sites, and their transparency and traceability back to raw data.

 

Nitrogenated and aliphatic organic vapors as possible drivers for marine secondary organic aerosol growth Nitrogenated and aliphatic organic vapors as possible drivers for marine secondary organic aerosol growth

Date added: 03/13/2013
Date modified: 03/13/2013
Filesize: 1.02 MB

DallOsto, Manuel,Darius Ceburnis, Ciaran Monahan, Douglas R. Worsnop,

Jakub Bialek, Markku Kulmala, Theo Kurtén, Mikael Ehn, John Wenger,

John Sodeau, Robert Healy, and Colin ODowd. (2012), Nitrogenated and aliphatic organic vapors as possible drivers for marine secondary organic aerosol growth, J. Geophys. Res., 117, D12311, doi:10.1029/2012JD017522.


Abstract. Measurements of marine aerosol chemistry, using state-of-the-art mass spectrometry, as well as aerosol microphysics, hygroscopicity and cloud condensation nuclei (CCN) activity were undertaken during new particle growth events. The events were detected in air advecting over North East (NE) Atlantic waters during the EUCAARI Intensive Observation Period in June 2008 at Mace Head, Ireland. During these growth events, the aerosol mass spectrometers illustrated increases in accumulation mode aerosol phase nitrogenated and aliphatic compounds thought to condense from the gas phase. Since the composition changes observed in the accumulation mode occurred simultaneously to the growth of the accumulation, Aitken and nucleation modes, the growth of both the nucleation mode and the Aitken mode is attributed to the condensation of these species. Nitrogenated compounds like amines are also plausible candidates in the nucleation process, as suggested by quantum mechanic calculations. It is also plausible that amides and organic nitrites, also identified by the mass spectrometers, are possible candidate chemical compounds, suggesting that multiple types of chemical species may be contributing. Given that these open ocean aerosol formation and growth events occur in very clean polar marine air masses, we suggest that the organic compounds responsible for particle formation and growth are mainly of biogenic origin. Despite increasing the particle number concentration, the initial effect is to suppress hygroscopicity and CCN activity.

Observations of 1,1-difluoroethane (HFC-152a) at AGAGE and SOGE monitoring stations in 1994–2004 and derived global and regional emission estimates Observations of 1,1-difluoroethane (HFC-152a) at AGAGE and SOGE monitoring stations in 1994–2004 and derived global and regional emission estimates

Date added: 08/05/2007
Date modified: 07/23/2009
Filesize: 2.28 MB
Greally, B. R., et al. (2007), Observations of 1,1-difluoroethane (HFC-152a) at AGAGE and SOGE monitoring stations in 1994–2004 and derived global and regional emission estimates, J. Geophys. Res., 112, D06308, doi:10.1029/2006JD007527.

Abstract


Ground-based in situ measurements of 1,1-difluoroethane (HFC-152a, CH3CHF2) which is regulated under the Kyoto Protocol are reported under the auspices of the AGAGE (Advanced Global Atmospheric Gases Experiment) and SOGE (System of Observation of halogenated Greenhouse gases in Europe) programs. Observations of HFC-152a at five locations (four European and one Australian) over a 10 year period were recorded. The annual average growth rate of HFC-152a in the midlatitude Northern Hemisphere has risen from 0.11 ppt/yr to 0.6 ppt/yr from 1994 to 2004. The Southern Hemisphere annual average growth rate has risen from 0.09 ppt/yr to 0.4 ppt/yr from 1998 to 2004. The 2004 average mixing ratio for HFC-152a was 5.0 ppt and 1.8 ppt in the Northern and Southern hemispheres, respectively. The annual cycle observed for this species in both hemispheres is approximately consistent with measured annual cycles at the same locations in other gases which are destroyed by OH. Yearly global emissions of HFC-152a from 1994 to 2004 are derived using the global mean HFC-152a observations and a 12-box 2-D model. The global emission of HFC-152a has risen from 7 Kt/yr to 28 Kt/yr from 1995 to 2004. On the basis of observations of above-baseline elevations in the HFC-152a record and a consumption model, regional emission estimates for Europe and Australia are calculated, indicating accelerating emissions from Europe since 2000. The overall European emission in 2004 ranges from 1.5 to 4.0 Kt/year, 5–15% of global emissions for 1,1-difluoroethane, while the Australian contribution is negligible at 5–10 tonnes/year, <0.05% of global emissions.

LIDAR studies of the atmospheric boundary layer and locally generated sea spray aerosol plumes at Ma LIDAR studies of the atmospheric boundary layer and locally generated sea spray aerosol plumes at Ma

Date added: 07/31/2002
Date modified: 07/02/2009
Filesize: 798.06 kB
Gerard Kunz, Gerrit de Leeuw, Colin O'Dowd, Edo Becker.LIDAR studies of the atmospheric boundary layer and locally generated sea spray aerosol plumes at Mace Head. J. Geophys. Res., 107, 10.1029/2001JD001240, 2002.

Abstract

 

A scanning backscatter lidar was used to measure the depth and structure of the coastal atmospheric boundary layer and the evolution of primary aerosol (sea spray) plumes produced by breaking waves during the New Particle Formation and Fate in the Coastal Environment (PARFORCE) campaign at the Mace Head Atmospheric Research Station (Ireland) in September 1998 and in June 1999. The PBL structure was observed to vary from a single-layer well-mixed structure to multilayered structures. Comparison with in situ aircraft measurements of temperature and humidity exhibited good agreement. Using the lidar in the scanning mode allowed two-dimensional profiling over a spatial scale of 10 km, revealing significant primary aerosol plumes produced by breaking waves, particularly in the surf zone and at high wind speeds on the open sea. The initial plume heights were some tens of meters and evolved to hundreds of meters while transported over only a few kilometers from the source. The plumes were traceable to distances of more than 10 km down wind from the source.

Aerosol analysis and forecast in the ECMWF Integrated Forecast System: 3. Evaluation by means of case studies Aerosol analysis and forecast in the ECMWF Integrated Forecast System: 3. Evaluation by means of case studies

Date added: 03/14/2013
Date modified: 03/14/2013
Filesize: 4.4 MB

Mangold, A., H. De Backer, B. De Paepe, S. Dewitte, I. Chiapello, Y. Derimian, M. Kacenelenbogen, J.‐F. Léon, N. Huneeus, M. Schulz, D. Ceburnis, C. O’Dowd, H. Flentje, S. Kinne, A. Benedetti, J.‐J. Morcrette and O. Boucher, Aerosol analysis and forecast in the ECMWF Integrated Forecast System: 3. Evaluation by means of case studies, J. Geophys. Res., 116, D03302, doi:10.1029/2010JD014864., 2011.


Abstract. A near real‐time system for assimilation and forecasts of aerosols, greenhouse and trace gases, extending the ECMWF Integrated Forecasting System (IFS), has been developed in the framework of the Global and regional Earth‐system Monitoring using Satellite and in‐situ data (GEMS) project. The GEMS aerosol modeling system is novel as it is the first aerosol model fully coupled to a numerical weather prediction model with data assimilation. A reanalysis of the period 2003–2009 has been carried out with the same system. During its development phase, the aerosol system was first run for the time period January 2003 to December 2004 and included sea salt, desert dust, organic matter, black carbon, and sulfate aerosols. In the analysis, Moderate Resolution Imaging Spectroradiometer (MODIS) total aerosol optical depth (AOD) at 550 nm over ocean and land (except over bright surfaces) was assimilated. This work evaluates the performance of the aerosol system by means of case studies. The case studies include (1) the summer heat wave in Europe in August 2003, characterized by forest fire aerosol and conditions of high temperatures and stagnation, favoring photochemistry and secondary aerosol formation, (2) a large Saharan dust event in March 2004, and (3) periods of high and low sea salt aerosol production. During the heat wave period in 2003, the linear correlation coefficients between modeled and observed AOD (550 nm) and between modeled and observed PM2.5 mass concentrations are 0.82 and 0.71, respectively, for all investigated sites together. The AOD is slightly and the PM2.5 mass concentration is clearly overestimated by the aerosol model during this period. The simulated sulfate mass concentration is significantly correlated with observations but is distinctly overestimated. The horizontal and vertical locations of the main features of the aerosol distribution during the Saharan dust outbreak are generally well captured, as well as the timing of the AOD peaks. The aerosol model simulates winter sea salt AOD reasonably well, however, showing a general overestimation. Summer sea salt events show a better agreement. Overall, the assimilation of MODIS AOD data improves the subsequent aerosol predictions when compared with observations, in particular concerning the correlation and AOD peak values. The assimilation is less effective in correcting a positive (PM2.5, sulfate mass concentration, Angström exponent) or negative (desert dust plume AOD) model bias.

 

 

 

 

 

 

Backround Bioaerosol Measurements at Mace Head Backround Bioaerosol Measurements at Mace Head

Date added: 08/26/1998
Date modified: 07/27/2009
Filesize: 113.15 kB

Kenny, C.M., and Jennings, S.G. (1998). Background bioaerosol measurements at Mace Head. J. Aerosol Sci., 29, S779-S780.


Abstract


Primary biological aerosol particles consist of airborne viable or non-viable material which are an ubiquitous component of the atmospheric aerosol. The types of particles considered as bioaerosols cover a very large size range, smallest in size are viruses (- 0.005 pm < radius< - 0.25 pm); larger particles include bacteria (r > - 0.2 pm), algae spores and fungi (r > - 0.5 pm) and pollen grains (r > - 5 pm), (Macher, 1993). Plant debris like leaf litter, parts of insects and human and animal epithhelial cells have a supposed r > - 1 pm. Assessment of bioaerosols is generally more complicated than that of non-bioaerosols - for example bioaerosol viability may be affected by a variety of stresses (desiccation, radiation, oxygen toxicity, chemical pollutants etc.) in the environment. A background bioaerosol measurement programme is currently taking place at the Mace Head Atmospheric Field Research Station, Carna, Co. Galway. Effective biological analysis of airborne particles requires samplers operating at a high flow rate and with the capability of concentrating the air particles into a fairly small liquid volume. Use has been made of a glass Aerojet cyclone high volume sampler which has been proven to be successful for the collection of bioaerosol material. Cyclones with spray wetters have been found to be gentle with airborne microorganisms and help to maintain cell viability levels. Utilising a blue protein dye,  uantitative determination of the percentage biological and non-biological species present in the aerosol has been made. The  staining solution reacts with the carboxyl group of a protein and therefore stains the protein-containing or biological particles blue. Non-biologicals are not changed by the stain. Under the light microscope the effects of the protein dye on different particle types can be seen and biological particles can be classified by their characteristic morphology and size. Filters have been examined using a Leitz microscope (Laborlux S), equipped with a 10x ocular lens and an objective lens, Plan 40, and size distribution spectra of the bioaerosol species have been measured. The samples were evaluated into size classes (3.5 urn < diameter < 40 urn) and size distributions of the total aerosol were obtained. The percentages of biological particles in the corresponding size classes are shown in Figure 1. The highest percentage of total biological particles < 10 urn occurs during the modified marine periods 07/25/97 and 07/l l/97 which reflects the passage of the air mass over land. The marine sample 07/15/97 shows a consistently high percentage of biological particles over the larger size ranges. The two predominant peaks occuring during the marine period 07/04/97 are caused by spores. Coupling size distribution spectra with corrected fluorescence spectra of the same air sample yield quantitative effective fluorescence cross-section per unit volume of background air. Analysis of size distribution spectra of the total aerosol, will be presented for both maritime and polluted air.

Global trends and emission estimates of CCl4 from in situ background observations from July 1978 to June 1996 Global trends and emission estimates of CCl4 from in situ background observations from July 1978 to June 1996

Date added: 08/01/1998
Date modified: 07/24/2009
Filesize: 1.15 MB

Simmonds, P. G., D. M. Cunnold, R. F. Weiss, R. G. Prinn, P. J. Fraser, A. McCulloch, F. N. Alyea, and S. O'Doherty (1998), Global trends and emission estimates of CCl4 from in situ background observations from July 1978 to June 1996, J. Geophys. Res., 103(D13), 16,017–16,027


Abstract


Atmospheric Lifetime Experiment/Global Atmospheric Gases Experiment/Advanced Global Atmospheric Gases Experiment (ALE/GAGE/AGAGE) measurements of CCl4 at five remote surface locations from 1978 to 1996 are reported. The Scripps Institution of Oceanography (SIO) 1993 absolute calibration scale is used, reducing the concentrations by a factor of 0.77 compared to previous ALE/GAGE reports. Atmospheric concentrations of CCl4 reached a peak in 1989-1990 of 104.4 ± 3.1 parts per trillion (ppt) and have since been decreasing 0.7 ± 0.1 ppt yr-1. Assuming an atmospheric lifetime of 42 ± 12 years, the emissions averaged 94-11+22 × 106 kg from 1979 to 1988 and 49-13+26 × 106 kg from 1991 to 1995. The reduction in the emissions in 1989-1990 coincided with a substantial decrease in the global production of the chlorofluorocarbons (CFCs). The total emission of CCl4 from countries that report annual production is estimated to have declined from 11% in 1972 to 4% in 1995 of the CCl4 needed to produce the CFC amounts reported. This implies that nonreporting countries released substantial amounts of CCl4 into the atmosphere in the 1980s and that their releases have exceeded those from the reporting countries since 1991.

Emissions from Ships with respect to Their Effects on Clouds Emissions from Ships with respect to Their Effects on Clouds

Date added: 08/06/2000
Date modified: 07/01/2009
Filesize: 302.93 kB

Hobbs, P.V., T.J. Garrett, and co-authors, 2000: Emissions from ships with respect to their effects on clouds, J. Atmos. Sci., 57, 2570-2590


Abstract


Emissions of particles, gases, heat, and water vapor from ships are discussed with respect to their potential for changing the microstructure of marine stratiform clouds and producing the phenomenon known as ship tracks. Airborne measurements are used to derive emission factors of SO2 and NO from diesel-powered and steam turbine-powered ships, burning low-grade marine fuel oil (MFO); they were ∼15-89 and ∼2-25 g kg-1 of fuel burned, respectively. By contrast a steam turbine-powered ship burning high-grade navy distillate fuel had an SO2 emission factor of ∼6 g kg-1. Various types of ships, burning both MFO and navy distillate fuel, emitted from ∼4 X 1015 to 2 X 1016 total particles per kilogram of fuel burned (∼4 X 1015-1.5 X 1016 particles per second). However, diesel-powered ships burning MFO emitted particles with a larger mode radius (∼0.03-0.05 μm) and larger maximum sizes than those powered by steam turbines burning navy distillate fuel (mode radius ∼0.02 μm). Consequently, if the particles have similar chemical compositions, those emitted by diesel ships burning MFO will serve as cloud condensation nuclei (CCN) at lower supersaturations (and will therefore be more likely to produce ship tracks) than the particles emitted by steam turbine ships burning distillate fuel. Since steam turbine-powered ships fueled by MFO emit particles with a mode radius similar to that of diesel-powered ships fueled by MFO, it appears that, for given ambient conditions, the type of fuel burned by a ship is more important than the type of ship engine in determining whether or not a ship will produce a ship track. However, more measurements are needed to test this hypothesis. The particles emitted from ships appear to be primarily organics, possibly combined with sulfuric acid produced by gas-to-particle conversion of SO2. Comparison of model results with measurements in ship tracks suggests that the particles from ships contain only about 10% water-soluble materials. Measurements of the total particles entering marine stratiform clouds from diesel-powered ships fueled by MFO, and increases in droplet concentrations produced by these particles, show that only about 12% of the particles serve as CCN. The fluxes of heat and water vapor from ships are estimated to be ∼2-22 MW and ∼0.5-1.5 kg s-1, respectively. These emissions rarely produced measurable temperature perturbations, and never produced detectable perturbations in water vapor, in the plumes from ships. Nuclear-powered ships, which emit heat but negligible particles, do not produce ship tracks. Therefore, it is concluded that heat and water vapor emissions do not play a significant role in ship track formation and that particle emissions, particularly from those burning low-grade fuel oil, are responsible for ship track formation. Subsequent papers in this special issue discuss and test these hypotheses.

 

Optical properties of the atmospheric aerosol at mace head Optical properties of the atmospheric aerosol at mace head

Date added: 08/07/1999
Date modified: 09/11/2009
Filesize: 118.21 kB

O'Reilly S.; Kleefeld C.; Jennings S.G.,Optical properties of the atmospheric aerosol at mace head  ,Journal of Aerosol Science, Volume 30, Supplement 1, September 1999 , pp. 631-632(2)


Abstract

 

The atmospheric aerosol is known to cause cooling of the earth's climate through radiative forcing. This forcing is comparable but of opposite sign to the radiative forcing due to greenhouse gases [1PCC, 1995]. However, unlike greenhouse gases, the atmospheric aerosol is not uniformly distributed about the globe. It is found to vary significantly both spatially and temporally. Therefore, an analysis of global radiative forcing due to the atmospheric aerosol requires an estimation of forcing on a regional scale. Characterisation of the optical properties of the local atmospheric aerosol forms an integral part of such an estimation. The scattering coefficient, Osp, and absorption coefficient, (Yap, of the atmospheric aerosol are basic input parameters to radiative forcing models. These parameters have been measured since 1996 and 1989, respectively, at the Global Atmospheric Watch (GAW/WMO) atmospheric research station at Mace Head (53°19'N, 9°54'W), located on the west coast of Ireland. The results of measurements from 7 th January 1997 to 12 th June ! 997 are presented. The scattering measurements were conducted with a TSI Model 3563 Integrating Nephelometer, operating at three wavelengths (450nm, 550nm and 700nm). It also had the
capability of measuring aerosol hemispheric backscatter coefficient from 90 ° to 180 °. Black carbon mass concentrations were measured using a Magee Scientific Model AE9 Aethalometer. The absorption coefficient for each wavelength was obtained by dividing black carbon mass concentrations by a constant, C; C(~=450nm)=1.5, C()~=550nm)=1.9 and C(L=700nm)=2.4 [Bodhaine, 1995], in order to compare with the aerosol scattering coefficients at these wavelengths. The scattering coefficient, Osp, for ~.=550nm ranged from 7 to 280 Mm -1 with an average and standard deviation of 76 + 49 Mm "l (geometric mean of 60 + 2 Mmt). The corresponding hemispheric backscattering coefficient, Cbsp, measurements were about an order of magnitude lower than (ysp ranging from 0.9 to 35 Mm "1 (geometric mean of 7 + 2 Mm-I). This results in a
hemispheric backscattered fraction, b, of 0.12 + 0.01 (geometric mean of 0.12). The AngstrOm exponent, describes the dependence of the aerosol scattering coefficient on wavelength, )~. The red-blue Angstr6m exponent (Ll=700nm, ~2=450nm) was found to range from -1.9 to 0.15 with an average of-0.66 + 0.7 (geometric mean of-0.69). The absorption coefficient, aap, for ~.=550nm ranged from 0.12 to 22 Mm "l and averaged 1.7 Mm "1 (geometric mean of 0.9 Mm'l). This results in an extinction coefficient, (yext, averaging
77.7Mm "1 (geometric mean of 53+2Mm'l). The scattering and absorption coefficients areused to calculate the single-scattering albedo, which describes the relative contributions of scattering and absorption to the total light extinction. The calculated albedo values ranged from 0.9 to 0.998 and averaged 0.97 + 0.02 (geometric mean of 0.97), indicating a highly scattering aerosol. The single scattering albedo exhibits a logarithmic correlation (R2=0.55, significant at a 99% confidence level) with black carbon concentrations. As black carbon levels increase, the albedo values can be seen to decrease  The scattering time series obtained were found to change with impact of different types of air mass (continental, marine and polar). The influence of synoptic meteorology on the scattering coefficient at Mace Head will be quantified by combining the pattern recognition capabilities of cluster analysis with air mass back-trajectory data.

Nature-times Weather Understanding rainfall Nature-times Weather Understanding rainfall

Date added: 08/01/1971
Date modified: 08/01/2008
Filesize: 336.23 kB

Coastal iodine emissions: Part 1. Release of I2 by Laminaria digitata in chamber experiments Coastal iodine emissions: Part 1. Release of I2 by Laminaria digitata in chamber experiments

Date added: 03/19/2013
Date modified: 03/19/2013
Filesize: 3.16 MB

Ashu-Ayem, E.R., U, Nitschke, C. Monahan, J. Chen, S.B. Darby, P.D. Smith, C.D. O’Dowd, D. B. Stengel, D.S. Venables. Coastal iodine emissions: Part 1. Release of I2 by Laminaria digitata in chamber experiments, dx.doi.org/10.1021/es204534v | Environ. Sci. Technol. 2012, 46, 10413−10421.


Abstract. Tidally exposed macroalgae emit large amounts of I2 and iodocarbons that produce hotspots of iodine chemistry and intense particle nucleation events in the coastal marine boundary layer. Current emission rates are poorly characterized, however, with reported emission rates varying by 3 orders of magnitude. In this study, I2 emissions from 25 Laminaria digitata samples were investigated in a simulation chamber using incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS). The chamber design allowed gradual extraction of seawater to simulate tidal emersion of algae. Samples were exposed to air with or without O3 and to varying irradiances. Emission of I2 occurred in four distinct stages: (1) moderate emissions from partially submerged samples; (2) a strong release by fully emerged samples; (3) slowing or stopping of I2 release; and (4) later pulses of I2 evident in some samples. Emission rates were highly variable and ranged from 7 to 616 pmol min1 gFW1 in ozone-free air, with a median value of 55 pmol min1 gFW1 for 20 samples.

 

Primary and secondary marine organic aerosols over the North Atlantic Ocean during the MAP experiment Primary and secondary marine organic aerosols over the North Atlantic Ocean during the MAP experiment

Date added: 03/19/2013
Date modified: 03/19/2013
Filesize: 1.9 MB

Decesari, S., E. Finessi, M. Rinaldi, M. Paglione, S. Fuzzi, E. G. Stephanou, T. Tziaras, A.Spyros, D. Ceburnis, C. O'Dowd, M. Dall’Osto, R. Harrison, J. Allan, H. Coe, M. C. Facchini, Primary and secondary marine organic aerosols over the North Atlantic Ocean during the MAP experiment, J. Geophys. Res., 116, D22210, doi:10.1029/2011JD016204, 2011


Abstract.

The organic chemical composition of atmospheric submicron particles in the marine boundary layer was characterized over the northeast Atlantic Ocean in summer 2006, during the season of phytoplankton blooms, in the frame of the Marine Aerosol Production (MAP) experiment. First measurements of water insoluble organic carbon (WIOC) in marine aerosol particles by nuclear magnetic resonance (NMR) spectroscopy showed that it is structurally similar to lipids, resembling the organic fraction of sea spray formed during bubble bursting experiments. The composition of the watersoluble organic carbon (WSOC) fraction was investigated by liquid chromatography mass spectrometry and by 1D and 2DNMR spectroscopy, and showed a less hydrophilic fraction containing traces of fatty acids and rich of alkanoic acids formed by lipid degradation, and a more hydrophilic fraction, containing more functionalized species encompassing short chain aliphatic acids and sulfate esters of hydroxyl carboxylic acids. The more oxidized fraction of WSOC accounts for the oxidized organic aerosol components, which can form by either gastoparticle conversion or extensive chemical aging of lipidcontaining primary particles, as also suggested by the parallel measurements using online mass spectrometric techniques (presented in a companion paper), showing oxidized organic substances internally mixed with sea salt particles. These measurements are also compared with online measurements using an Aerosol TimeOfFlight Mass Spectrometer (ATOFMS) and Aerodyne Aerosol Mass Spectrometer (AMS). Given the large variability in the chemical composition of marine organic aerosol particles, a multitechnique approach is recommended to reduce method dependent categorizations and oversimplifications and to improve the comparability with the results obtained in different oceanic areas.

 

Igac August 2001 Igac August 2001

Date added: 08/06/2001
Date modified: 08/06/2008
Filesize: 1.91 MB

Nature-times Weather Understanding rainfall Nature-times Weather Understanding rainfall

Date added: 08/01/1971
Date modified: 09/11/2009
Filesize: 336.23 kB

Aerosol decadal trends – Part 2: In-situ aerosol particle number concentrations at GAW and ACTRIS stations Aerosol decadal trends – Part 2: In-situ aerosol particle number concentrations at GAW and ACTRIS stations

Date added: 03/12/2013
Date modified: 03/12/2013
Filesize: 6.1 MB

Asmi, A., M. Collaud Coen, J.A. Ogren, E. Andrews, P. Sheridan, A. Jefferson, E. Weingartner, U. Baltensperger, N. Bukowiecki, H. Lihavainen, N. Kivekäs, E. Asmi, P. P. Aalto, M. Kulmala, A. Wiedensohler, W. Birmili, A. Hamed, C. O'Dowd, S. G Jennings, R. Weller, H. Flentje, A. M. Fjaeraa, M. Fiebig, C. L. Myhre, A. G. Hallar, E. Swietlicki, A. Kristensson, and P. Laj,Aerosol decadal trends – Part 2: In-situ aerosol particle number concentrations at GAW and ACTRIS stations, Atmos. Chem. Phys., 13, 895-916, 2013, www.atmos-chem-phys.net/13/895/2013/ doi:10.5194/acp-13-895-2013


Abstract. We have analysed the trends of total aerosol particle number concentrations (N) measured at long-term measurement stations involved either in the Global Atmosphere Watch (GAW) and/or EU infrastructure project ACTRIS. The sites are located in Europe, North America, Antarctica, and on Pacific Ocean islands. The majority of the sites showed clear decreasing trends both in the full-length time series, and in the intra-site comparison period of 2001–2010, especially during the winter months. Several potential driving processes for the observed trends were studied, and even though there are some similarities between N trends and air temperature changes, the most likely cause of many northern hemisphere trends was found to be decreases in the anthropogenic emissions of primary particles, SO2 or some co-emitted species. We could not find a consistent agreement between the trends of N and particle optical properties in the few stations with long time series of all of these properties. The trends of N and the proxies for cloud condensation nuclei (CCN) were generally consistent in the few European stations where the measurements were available. This work provides a useful comparison analysis for modelling studies of trends in aerosol number concentrations.

 

Connecting marine productivity to sea-spray via nanoscale biological processes: Phytoplankton Dance or Death Disco? Connecting marine productivity to sea-spray via nanoscale biological processes: Phytoplankton Dance or Death Disco?

Date added: 02/02/2016
Date modified: 02/03/2016
Filesize: 1.03 MB

Connecting marine productivity to sea-spray via nanoscale biological processes: Phytoplankton Dance or Death Disco? O'Dowd, C,Ceburnis, D,Ovadnevaite, J,Bialek, J,Stengel, DB,Zacharias, M,Nitschke, U,Connan, S,Rinaldi, M,Fuzzi, S,Decesari, S,Facchini, MC,Marullo, S,Santoleri, R,Dell'Anno, A,Corinaldesi, C,Tangherlini, M,Danovaro, R., Scientific Reports 5, Article number: 14883, doi:10.1038/srep14883 (2015)


Bursting bubbles at the ocean-surface produce airborne salt-water spray-droplets, in turn, forming climate-cooling marine haze and cloud layers. The reflectance and ultimate cooling effect of these layers is determined by the spray’s water-uptake properties that are modified through entrainment of ocean-surface organic matter (OM) into the airborne droplets. We present new results illustrating a clear dependence of OM mass-fraction enrichment in sea spray (OMss) on both phytoplankton-biomass, determined from Chlorophyll-a (Chl-a) and Net Primary Productivity (NPP). The correlation coefficient for OMss as a function of Chl-a increased form 0.67 on a daily timescale to 0.85 on a monthly timescale. An even stronger correlation was found as a function of NPP, increasing to 0.93 on a monthly timescale. We suggest the observed dependence is through the demise of the bloom, driven by nanoscale biological processes (such as viral infections), releasing large quantities of transferable OM comprising cell debris, exudates and other colloidal materials. This OM, through aggregation processes, leads to enrichment in sea-spray, thus demonstrating an important coupling between biologically-driven plankton bloom termination, marine productivity and sea-spray modification with potentially significant climate impacts.



 

«StartPrev11NextEnd»
Page 11 of 11
Copyright © 2018 Atmospheric Physics Research Cluster. All Rights Reserved.
Joomla! is Free Software released under the GNU/GPL License.
 
None