scholarly journals Classification of Clouds Sampled at the Puy de Dôme Station (France) Based on Chemical Measurements and Air Mass History Matrices

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 732
Author(s):  
Pascal Renard ◽  
Angelica Bianco ◽  
Jean-Luc Baray ◽  
Maxime Bridoux ◽  
Anne-Marie Delort ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Principal Component ◽  
Cloud Microphysics ◽  
Back Trajectory ◽  
Air Mass ◽  
Air Masses ◽  
Chemical Measurements ◽  
History Of ◽  
High Concentrations ◽  
The Impact

A statistical analysis of 295 cloud samples collected at the Puy de Dôme station in France (PUY), covering the period 2001–2018, was conducted using principal component analysis (PCA), agglomerative hierarchical clustering (AHC), and partial least squares (PLS) regression. Our model classified the cloud water samples on the basis of their chemical concentrations and of the dynamical history of their air masses estimated with back-trajectory calculations. The statistical analysis split our dataset into two sets, i.e., the first set characterized by westerly air masses and marine characteristics, with high concentrations of sea salts and the second set having air masses originating from the northeastern sector and the “continental” zone, with high concentrations of potentially anthropogenic ions. It appears from our dataset that the influence of cloud microphysics remains minor at PUY as compared with the impact of the air mass history, i.e., physicochemical processes, such as multiphase reactivity.

scholarly journals Classification of clouds sampled at the puy de Dôme (France) based on 10 yr of monitoring of their physicochemical properties

2014 ◽  
Vol 14 (3) ◽  
pp. 1485-1506 ◽  
Author(s):  
L. Deguillaume ◽  
T. Charbouillot ◽  
M. Joly ◽  
M. Vaïtilingom ◽  
M. Parazols ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Chemical Composition ◽  
Inorganic Compounds ◽  
Average Concentration ◽  
Anthropogenic Sources ◽  
Back Trajectory ◽  
Data Set ◽  
Air Masses ◽  
High Concentrations ◽  
Inorganic Constituents

Abstract. Long-term monitoring of the chemical composition of clouds (73 cloud events representing 199 individual samples) sampled at the puy de Dôme (pdD) station (France) was performed between 2001 and 2011. Physicochemical parameters, as well as the concentrations of the major organic and inorganic constituents, were measured and analyzed by multicomponent statistical analysis. Along with the corresponding back-trajectory plots, this allowed for distinguishing four different categories of air masses reaching the summit of the pdD: polluted, continental, marine and highly marine. The statistical analysis led to the determination of criteria (concentrations of inorganic compounds, pH) that differentiate each category of air masses. Highly marine clouds exhibited high concentrations of Na+ and Cl−; the marine category presented lower concentration of ions but more elevated pH. Finally, the two remaining clusters were classified as "continental" and "polluted"; these clusters had the second-highest and highest levels of NH4+, NO3−, and SO24−, respectively. This unique data set of cloud chemical composition is then discussed as a function of this classification. Total organic carbon (TOC) is significantly higher in polluted air masses than in the other categories, which suggests additional anthropogenic sources. Concentrations of carboxylic acids and carbonyls represent around 10% of the organic matter in all categories of air masses and are studied for their relative importance. Iron concentrations are significantly higher for polluted air masses and iron is mainly present in its oxidation state (+II) in all categories of air masses. Finally, H2O2 concentrations are much more varied in marine and highly marine clouds than in polluted clouds, which are characterized by the lowest average concentration of H2O2. This data set provides concentration ranges of main inorganic and organic compounds for modeling purposes on multiphase cloud chemistry.

scholarly journals Relationships between submicrometer particulate air pollution and air mass history in Beijing, China, 2004–2006

2008 ◽  
Vol 8 (20) ◽  
pp. 6155-6168 ◽  
Author(s):  
B. Wehner ◽  
W. Birmili ◽  
F. Ditas ◽  
Z. Wu ◽  
M. Hu ◽  
...  
Keyword(s):  
Air Pollution ◽  
Large Scale ◽  
Northwest China ◽  
Back Trajectory ◽  
Anthropogenic Aerosol ◽  
Air Mass ◽  
Air Masses ◽  
Rapid Economic Growth ◽  
Trajectory Classification ◽  
History Of

Abstract. The Chinese capital Beijing is one of the global megacities where the effects of rapid economic growth have led to complex air pollution problems that are not well understood. In this study, ambient particle number size distributions in Beijing between 2004 and 2006 are analysed as a function of regional meteorological transport. An essential result is that the particle size distribution in Beijing depends to large extent on the history of the synoptic scale air masses. A first approach based on manual back trajectory classification yielded differences in particulate matter mass concentration by a factor of two between four different air mass categories, including three main wind directions plus the case of stagnant air masses. A back trajectory cluster analysis refined these results, yielding a total of six trajectory clusters. Besides the large scale wind direction, the transportation speed of an air mass was found to play an essential role on the PM concentrations in Beijing. Slow-moving air masses were shown to be associated with an effective accumulation of surface-based anthropogenic emissions due to both, an increased residence time over densely populated land, and their higher degree of vertical stability. For the six back trajectory clusters, differences in PM1 mass concentrations by a factor of 3.5, in the mean air mass speed by a factor of 6, and in atmospheric visibility by a factor of 4 were found. The main conclusion is that the air quality in Beijing is not only degraded by anthropogenic aerosol sources from within the megacity, but also by sources across the entire Northwest China plain depending on the meteorological situation.

scholarly journals Relationships between submicrometer particulate air pollution and air mass history in Beijing, China, 2004–2006

2008 ◽  
Vol 8 (3) ◽  
pp. 11321-11362 ◽  
Author(s):  
B. Wehner ◽  
W. Birmili ◽  
F. Ditas ◽  
Z. Wu ◽  
M. Hu ◽  
...  
Keyword(s):  
Air Pollution ◽  
Large Scale ◽  
Northwest China ◽  
Back Trajectory ◽  
Anthropogenic Aerosol ◽  
Air Mass ◽  
Air Masses ◽  
Rapid Economic Growth ◽  
Trajectory Classification ◽  
History Of

Abstract. The Chinese capital Beijing is one of the global megacities where the effects of rapid economic growth have led to complex air pollution problems that are not well understood. In this study, ambient particle number size distributions in Beijing between 2004 and 2006 are analysed as a function of regional meteorological transport. An essential result is that the particle size distribution in Beijing depends to large extent on the history of the synoptic scale air masses. A first approach based on manual back trajectory classification yielded differences in particulate matter mass concentration (PM1 and PM10) by a factor of two between four different air mass categories, including three main wind directions plus the case of stagnant air masses. A back trajectory cluster analysis refined these results, yielding a total of six trajectory clusters. Besides the large scale wind direction, the transportation speed of an air mass was found to play an essential role on the PM concentrations in Beijing. Slow-moving air masses were shown to be associated with an effective accumulation of surface-based anthropogenic emissions due to both, an increased residence time over densely populated land, and their higher degree of vertical stability. For the six back trajectory clusters, differences in PM1 mass concentrations by a factor of 3.5, in the mean air mass speed by a factor of 6, and in atmospheric visibility by a factor of 4 were found. The main conclusion is that the air quality in Beijing is not only degraded by anthropogenic aerosol sources from within the megacity, but also by sources across the entire Northwest China plain depending on the meteorological situation.

scholarly journals Inclusion of biomass burning in WRF-Chem: impact of wildfires on weather forecasts

2011 ◽  
Vol 11 (11) ◽  
pp. 5289-5303 ◽  
Author(s):  
G. Grell ◽  
S. R. Freitas ◽  
M. Stuefer ◽  
J. Fast
Keyword(s):  
Biomass Burning ◽  
Cloud Model ◽  
Cloud Condensation Nuclei ◽  
Cloud Microphysics ◽  
Fire Season ◽  
Strong Impact ◽  
Emission Rates ◽  
Weather Forecasts ◽  
High Concentrations ◽  
The Impact

Abstract. A plume rise algorithm for wildfires was included in WRF-Chem, and applied to look at the impact of intense wildfires during the 2004 Alaska wildfire season on weather simulations using model resolutions of 10 km and 2 km. Biomass burning emissions were estimated using a biomass burning emissions model. In addition, a 1-D, time-dependent cloud model was used online in WRF-Chem to estimate injection heights as well as the vertical distribution of the emission rates. It was shown that with the inclusion of the intense wildfires of the 2004 fire season in the model simulations, the interaction of the aerosols with the atmospheric radiation led to significant modifications of vertical profiles of temperature and moisture in cloud-free areas. On the other hand, when clouds were present, the high concentrations of fine aerosol (PM2.5) and the resulting large numbers of Cloud Condensation Nuclei (CCN) had a strong impact on clouds and cloud microphysics, with decreased precipitation coverage and precipitation amounts during the first 12 h of the integration. During the afternoon, storms were of convective nature and appeared significantly stronger, probably as a result of both the interaction of aerosols with radiation (through an increase in CAPE) as well as the interaction with cloud microphysics.

scholarly journals Water vapor increase in the lower stratosphere of the Northern Hemisphere due to the Asian monsoon anticyclone observed during the TACTS/ESMVal campaigns

2018 ◽  
Vol 18 (4) ◽  
pp. 2973-2983 ◽  
Author(s):  
Christian Rolf ◽  
Bärbel Vogel ◽  
Peter Hoor ◽  
Armin Afchine ◽  
Gebhard Günther ◽  
...  
Keyword(s):  
Water Vapor ◽  
Northern Hemisphere ◽  
Asian Monsoon ◽  
Eastern China ◽  
Potential Temperature ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Air Mass ◽  
Air Masses ◽  
The Impact

Abstract. The impact of air masses originating in Asia and influenced by the Asian monsoon anticyclone on the Northern Hemisphere stratosphere is investigated based on in situ measurements. A statistically significant increase in water vapor (H2O) of about 0.5 ppmv (11 %) and methane (CH4) of up to 20 ppbv (1.2 %) in the extratropical stratosphere above a potential temperature of 380 K was detected between August and September 2012 during the HALO aircraft missions Transport and Composition in the UT/LMS (TACTS) and Earth System Model Validation (ESMVal). We investigate the origin of the increased water vapor and methane using the three-dimensional Chemical Lagrangian Model of the Stratosphere (CLaMS). We assign the source of the moist air masses in the Asian region (northern and southern India, eastern China, southeast Asia, and the tropical Pacific) based on tracers of air mass origin used in CLaMS. The water vapor increase is correlated with an increase of the simulated Asian monsoon air mass contribution from about 10 % in August to about 20 % in September, which corresponds to a doubling of the influence from the Asian monsoon region. Additionally, back trajectories starting at the aircraft flight paths are used to differentiate transport from the Asian monsoon anticyclone and other source regions by calculating the Lagrangian cold point (LCP). The geographic location of the LCPs, which indicates the region where the set point of water vapor mixing ratio along these trajectories occurs, can be predominantly attributed to the Asian monsoon region.

scholarly journals Structure Function Analysis of Water Vapor Simulated with a Convection-Permitting Model and Comparison to Airborne Lidar Observations

2017 ◽  
Vol 74 (4) ◽  
pp. 1201-1210
Author(s):  
Tobias Selz ◽  
Lucas Fischer ◽  
George C. Craig
Keyword(s):  
Water Vapor ◽  
Structure Function ◽  
Airborne Lidar ◽  
Sensitivity Analyses ◽  
Small Scale ◽  
Limited Area ◽  
Air Mass ◽  
Scaling Properties ◽  
Air Masses ◽  
The Impact

Abstract The spatial scale dependence of midlatitude water vapor variability in the high-resolution limited-area model COSMO is evaluated using diagnostics of scaling behavior. Past analysis of airborne lidar measurements showed that structure function scaling exponents depend on the corresponding airmass characteristics, and that a classification of the troposphere into convective and nonconvective layers led to significantly different power-law behaviors for each of these two regimes. In particular, scaling properties in the convective air mass were characterized by rough and highly intermittent data series, whereas the nonconvective regime was dominated by smoother structures with weaker small-scale variability. This study finds similar results in a model simulation with an even more pronounced distinction between the two air masses. Quantitative scaling diagnostics agree well with measurements in the nonconvective air mass, whereas in the convective air mass the simulation shows a much higher intermittency. Sensitivity analyses were performed using the model data to assess the impact of limitations of the observational dataset, which indicate that analyses of lidar data most likely underestimated the intermittency in convective air masses due to the small samples from single flight tracks, which led to a bias when data with poor fits were rejected. Though the quantitative estimation of intermittency remains uncertain for convective air masses, the ability of the model to capture the dominant weather regime dependence of water vapor scaling properties is encouraging.

scholarly journals Heavy Metals in PM10 Aerosols Over an Urban Industrial City

2019 ◽  
Vol 9 (1) ◽  
pp. 1402-1408
Keyword(s):  
Heavy Metal ◽  
Anthropogenic Activities ◽  
Winter Season ◽  
Principal Component ◽  
Heavy Metal Concentration ◽  
Back Trajectory ◽  
Air Masses ◽  
Back Trajectory Analysis ◽  
Source Correlation ◽  
Heavy Metal Determination

PM10 aerosols were monitored and analyzed for heavy metal concentration at Raipur city Chhattisgarh, India for possible source identification of pollutants. Sampling of PM10 aerosols was carried out by using respirable dust sampler during the year 2016. Daily PM10 average concentrations varied between 122.033 and 197.854 µg/m3, 91.350 and 133.950 µg/m3 and 112.770 and 480.170 µg/m3 in summer, monsoon and winter respectively. Chemical analysis of PM10 samples was carried out for heavy metal determination. Heavy metal (Fe, Mn, Ni and Pb) were analyzed with the help of atomic absorption spectroscopy (AAS) and found in the range of 2.713-36.862, 0.131-9.129. 0.880-4.195 and 0.015-0.321 µg/m3 for Fe, Mn, Pb and Ni respectively. PM10 concentrations shows distinct seasonal variation being twice in winter season than in summer; winter (mean: 241.820 ± 33.912 µg/m3) > summer (mean: 159.512 ± 14.360 µg/m3) > monsoon (mean: 107.480 ± 9.213 µg/m3). The concentration of heavy metal was different in all the seasons depending on their sources. Identification of possible sources was done by principal component analysis (PCA) illustrating industrial activities, soil (crustal) dust and biomass burning as the major sources in the region. The back trajectory analysis of the air masses depicts that the local anthropogenic activities affect the concentration of pollutants at the source. Correlation analysis between the heavy metal concentrations agreed the results obtained by PCA. The work helped in observing the seasonal trend of particulate matter concentrations and in identification of major sources of air pollution in the city.

scholarly journals Airborne observations and modeling of springtime stratosphere-to-troposphere transport over California

2013 ◽  
Vol 13 (4) ◽  
pp. 10157-10192 ◽  
Author(s):  
E. L. Yates ◽  
L. T. Iraci ◽  
M. C. Roby ◽  
R. B. Pierce ◽  
M. S. Johnson ◽  
...  
Keyword(s):  
Air Quality ◽  
Free Troposphere ◽  
Air Mass ◽  
Air Masses ◽  
Airborne Measurements ◽  
Mixing Ratios ◽  
Stratospheric Intrusion ◽  
Tropospheric O3 ◽  
Carbon Dioxide Co2 ◽  
The Impact

Abstract. Stratosphere-to-troposphere transport (STT) results in air masses of stratospheric origin intruding into the free troposphere. Once in the free troposphere, O3-rich stratospheric air can be transported and mixed with tropospheric air masses, contributing to the tropospheric O3 budget. Evidence of STT can be identified based on the differences in the trace gas composition of the two regions. Because ozone (O3) is present in such large quantities in the stratosphere compared to the troposphere, it is frequently used as a tracer for STT events. This work reports on airborne in situ measurements of O3 and other trace gases during two STT events observed over California, USA. The first, on 14 May 2012, was associated with a cut-off low, and the second, on 5 June 2012, occurred during a post-trough, building ridge event. In each STT event, airborne measurements identified high O3 within a stratospheric intrusion which was observed as low as 3 km above sea level. During both events the stratospheric air mass was characterized by elevated O3 mixing ratios and reduced carbon dioxide (CO2) and water vapor. The reproducible observation of reduced CO2 within the stratospheric air mass supports the use of non-conventional tracers as an additional method for detecting STT. A detailed meteorological analysis of each STT event is presented and observations are interpreted with the Realtime Air Quality Modeling System (RAQMS). The implications of the two STT events are discussed in terms of the impact on the total tropospheric O3 budget and the impact on air quality and policy-making.

scholarly journals Marine productivity and synoptic meteorology drive summer-time variability in Southern Ocean aerosols

2020 ◽  
Vol 20 (13) ◽  
pp. 8047-8062
Author(s):  
Joel Alroe ◽  
Luke T. Cravigan ◽  
Branka Miljevic ◽  
Graham R. Johnson ◽  
Paul Selleck ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Cloud Condensation Nuclei ◽  
Large Diameter ◽  
Convective Transport ◽  
Sea Spray ◽  
Strong Wind ◽  
Condensation Nuclei ◽  
Air Mass ◽  
Air Masses ◽  
High Concentrations

Abstract. Cloud–radiation interactions over the Southern Ocean are not well constrained in climate models, in part due to uncertainties in the sources, concentrations, and cloud-forming potential of aerosol in this region. To date, most studies in this region have reported measurements from fixed terrestrial stations or a limited set of instrumentation and often present findings as broad seasonal or latitudinal trends. Here, we present an extensive set of aerosol and meteorological observations obtained during an austral summer cruise across the full width of the Southern Ocean south of Australia. Three episodes of continental-influenced air masses were identified, including an apparent transition between the Ferrel atmospheric cell and the polar cell at approximately 64∘ S, and accompanied by the highest median cloud condensation nuclei (CCN) concentrations, at 252 cm−3. During the other two episodes, synoptic-scale weather patterns diverted air masses across distances greater than 1000 km from the Australian and Antarctic coastlines, respectively, indicating that a large proportion of the Southern Ocean may be periodically influenced by continental air masses. In all three cases, a highly cloud-active accumulation mode dominated the size distribution, with up to 93 % of the total number concentration activating as CCN. Frequent cyclonic weather conditions were observed at high latitudes and the associated strong wind speeds led to predictions of high concentrations of sea spray aerosol. However, these modelled concentrations were not achieved due to increased aerosol scavenging rates from precipitation and convective transport into the free troposphere, which decoupled the air mass from the sea spray flux at the ocean surface. CCN concentrations were more strongly impacted by high concentrations of large-diameter Aitken mode aerosol in air masses which passed over regions of elevated marine biological productivity, potentially contributing up to 56 % of the cloud condensation nuclei concentration. Weather systems were vital for aerosol growth in biologically influenced air masses and in their absence ultrafine aerosol diameters were less than 30 nm. These results demonstrate that air mass meteorological history must be considered when modelling sea spray concentrations and highlight the potential importance of sub-grid-scale variability when modelling atmospheric conditions in the remote Southern Ocean.

scholarly journals Seasonal variations in the synoptic climatology of air pollution in Birmingham, UK

2021 ◽  
Author(s):  
Edward C. Hodgson ◽  
Ian D. Phillips
Keyword(s):  
Principal Component ◽  
Cold Season ◽  
Meteorological Conditions ◽  
Synoptic Climatology ◽  
Air Mass ◽  
Pollutant Concentrations ◽  
High Concentrations ◽  
Air Mass Types ◽  
Temperature Inversions ◽  
Pollution Episodes

AbstractA synoptic typing approach was undertaken to examine the seasonal relationship (winter versus summer) between air mass types and pollutant concentrations of O3, PM10, NOx, NO2 and CO in Birmingham, UK, from 2000 to 2015. Daily means of seven surface meteorological variables were entered into a P-mode principal component analysis. Three principal components explained 72.2% (72.9%) of the variance in winter (summer). Cluster analysis was used to group together days with similar PC scores and thus similar meteorological conditions. Six clusters provided the best air mass classification in both seasons. High pollutant concentrations were associated with anticyclonic types. In particular, tropical (polar) continental air mass type was most likely to produce extremely high concentrations in summer (winter). In winter, a sequence of Polar Continental (cool and humid) and Binary Mid-latitude Anticyclonic Maritime—Sub-Polar Cyclonic Maritime (cold and dry) induced severe pollution episodes in all pollutants. Whilst the mean duration of severe pollution episodes varied little between winter and summer (O3 was an exception, with severe episodes lasting 20% longer in summer), high pollutant extremes were more common in winter. This was due to more favourable meteorological conditions (e.g. temperature inversions) and increased anthropogenic emissions during the cold season.

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