Atmosphere

512 KiB

Open AccessArticle

Characteristics and Seasonal Variations of Carbonaceous Species in PM_2.5 in Taiyuan, China

by Qiusheng He, Wendi Guo, Guixiang Zhang, Yulong Yan and Laiguo Chen

Atmosphere 2015, 6(6), 850-862; https://doi.org/10.3390/atmos6060850 - 19 Jun 2015

Cited by 49 | Viewed by 5933

Seasonal characteristics of PM_2.5, organic carbon (OC) and elemental carbon (EC) were studied in Taiyuan from 2009 to 2010. PM_2.5 samples were collected by pre-baked quartz filters with high-volume air sampler, and then OC and EC were analyzed by thermal/optical [...] Read more.

Seasonal characteristics of PM_2.5, organic carbon (OC) and elemental carbon (EC) were studied in Taiyuan from 2009 to 2010. PM_2.5 samples were collected by pre-baked quartz filters with high-volume air sampler, and then OC and EC were analyzed by thermal/optical reflectance method. The annual average concentrations of PM_2.5, OC and EC were 220.2, 37.4 and 19.6 µg/m³ respectively, which were higher than those in most regions in China. Total carbonaceous aerosol (TCA) accounted for more than one third of the total PM_2.5 mass. The levels of PM_2.5, OC and EC were the highest in winter, followed by spring, fall and summer. OC and EC were well correlated in summer compared with other seasons, indicating the presence of other additional sources such as biomass burning in fall, coal combustion for heating in winter and dust in spring. Higher OC/EC ratios in winter might be primarily attributed to the significant increase of direct emission of OC as a result of coal and biomass combustion, and also cooling effect of carbonaceous aerosols due to low temperature and stagnated atmospheric condition. These results showed that the pollution of carbonaceous particles in Taiyuan was serious, and might be an inducing factor of dust haze, especially in winter. Full article

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1470 KiB

Open AccessArticle

Application of Multiple Wind Retrieval Algorithms in Nowcasting

by Nan Li, Ming Wei, Ben Niu, Jiawen Pan, Wengang Zhang and Wei Guo

Atmosphere 2015, 6(6), 834-849; https://doi.org/10.3390/atmos6060834 - 18 Jun 2015

Cited by 3 | Viewed by 4555

Abstract

Multiple wind retrieval algorithms are performed to retrieve wind fields, based on which radar reflectivity is extrapolated to implement nowcasting. The frequently used nowcasting algorithm COTREC (continuity of tracking radar echo by correlation), based on the reflectivity and wind retrieval algorithm GVAD (gradient [...] Read more.

Multiple wind retrieval algorithms are performed to retrieve wind fields, based on which radar reflectivity is extrapolated to implement nowcasting. The frequently used nowcasting algorithm COTREC (continuity of tracking radar echo by correlation), based on the reflectivity and wind retrieval algorithm GVAD (gradient velocity azimuth display), based on radial velocity are used. The wind fields retrieved by the two methods are taken as motion vectors to give a 60-min forecast of radar reflectivity. Comparison analysis on precipitation events shows that GVAD can be used in operational nowcasting as COTREC performs and for stable precipitation duration, COTREC gives better nowcasting results than GVAD, while, for evolving precipitation duration, GVAD gives better nowcasting results than COTREC. Full article

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1159 KiB

Open AccessArticle

Gaseous Products of Incense Coil Combustion Extracted by Passive Solid Phase Microextraction Samplers

by Wen-Hsi Cheng, Chin-Hsing Lai, Wen-Jiunn Tzeng, Chyn Her and Ya-Han Hsu

Atmosphere 2015, 6(6), 822-833; https://doi.org/10.3390/atmos6060822 - 16 Jun 2015

Cited by 5 | Viewed by 6398

Abstract

Burning incense indoors is a common behavior in Southeast Asia. In this investigation, needle trap samplers (NTS), a novel, green analytical technology is used for sampling gaseous combustion by-products from sandalwood incense coils. To extract indoor volatile organic compounds (VOCs), two NTS are [...] Read more.

Burning incense indoors is a common behavior in Southeast Asia. In this investigation, needle trap samplers (NTS), a novel, green analytical technology is used for sampling gaseous combustion by-products from sandalwood incense coils. To extract indoor volatile organic compounds (VOCs), two NTS are prepared, one using 60–80 mesh and the other using 100–120 mesh divinylbenzene (DVB) particles packed in 22-gauge stainless steel needles. This work compares extraction efficiency of an NTS and that of a commercially available 100 μm polydimethylsiloxane solid phase microextration (PDMS-SPME) fiber sampler. Experimental results indicated that the 100–120 mesh DVB-NTS performed best among all samplers during a 1 h sampling period. The main extracted compounds were toluene, ethylbenzene, propane, chloromethane, 1,3-butadiene, methanol and dichloromethane. The potential use of small badge-sized or pen-sized NTS for the indoor atmosphere and occupational hygiene applications is addressed. Full article

(This article belongs to the Special Issue Indoor and Outdoor Air Quality)

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603 KiB

Open AccessArticle

Land-Atmosphere Transfer Parameters in the Brazilian Pantanal during the Dry Season

by Paolo Martano, Edson Pereira Marques Filho and Leonardo Deane De Abreu Sá

Atmosphere 2015, 6(6), 805-821; https://doi.org/10.3390/atmos6060805 - 10 Jun 2015

Cited by 1 | Viewed by 4831

Abstract

The Brazilian region of Pantanal is one of the largest wetlands in the world, characterized by a wet season, in which it is covered by a shallow water layer, and a dry season, in which the water layer disappears. The aim of this [...] Read more.

The Brazilian region of Pantanal is one of the largest wetlands in the world, characterized by a wet season, in which it is covered by a shallow water layer, and a dry season, in which the water layer disappears. The aim of this study is the estimation of the main parameters (drag coefficients and surface scale lengths) involved in modelling the surface atmosphere transfer of momentum, heat and water vapor from the dataset of the second Interdisciplinary Pantanal Experiment (IPE2). The roughness parameters and the stability correction parameters have been estimated in the framework of the similarity theory for the vertical profiles of wind speed and temperature. Thus, a previously-developed methodology was adapted to the available dataset from the IPE2 five-level mast. The results are in reasonable agreement with the available literature. An attempt to obtain the scalar transfer parameters for water vapor has been performed by a Penman–Monteith approach using a two-component surface resistance in parallel between a vegetation and a bare soil part. The parameters of the model have been calibrated using a non-linear regression method. The scalar drag coefficient retrieved in this way is in agreement with that calculated by the flux-gradient approach for the sensible heat flux. Eventually, an evaluation of the vegetation contribution to the total vapor flux is given. Full article

(This article belongs to the Special Issue Land-Atmosphere Interaction in Micrometeorology and Pollution Dispersal)

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15873 KiB

Open AccessArticle

Impacts of Boundary Conditions on the Simulation of Atmospheric Fields Using RegCM4 over CORDEX East Asia

by Myoung Seok Suh and Seok Geun Oh

Atmosphere 2015, 6(6), 783-804; https://doi.org/10.3390/atmos6060783 - 5 Jun 2015

Cited by 8 | Viewed by 4819

Abstract

The impacts of boundary conditions (BCs) on simulations of RegCM4 for mid-to-upper atmospheric fields over the CORDEX (COordinated Regional Downscaling EXperiment) East Asia domain were investigated using two datasets from integrations over 20 years (1989–2008) with two BCs (ERA and R2). The two [...] Read more.

The impacts of boundary conditions (BCs) on simulations of RegCM4 for mid-to-upper atmospheric fields over the CORDEX (COordinated Regional Downscaling EXperiment) East Asia domain were investigated using two datasets from integrations over 20 years (1989–2008) with two BCs (ERA and R2). The two datasets showed large differences for the atmospheric variables regardless of the geographic locations, heights, and seasons. The ERA dataset at 850 hPa displayed stronger northerly winds in the western Pacific Ocean, colder temperatures around northern India, and higher relative humidity compared with the R2 dataset during summer. The large differences in the BCs resulted in the significantly different simulations of RegCM4 in both surface and atmospheric variables. The temperatures and wind simulated at 850 hPa with the ERA dataset were warmer and stronger, respectively, than those simulated with the R2 dataset during summer. In addition, RegCM4 with the ERA dataset as a BC generally simulated a stronger southerly wind at 850 hPa over eastern China and more unstable environments than with the R2 dataset, and accordingly generated more precipitation over the eastern part of the domain. Contrary to the forcing data, the trends of simulated relative humidity and the mixing ratios from the two different BCs showed similar patterns irrespective of height and season. The significant impacts of the BCs on the simulation results indicate the importance of BCs in regional climate simulations. Full article

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5145 KiB

Open AccessArticle

Impact of Coupled NO_x/Aerosol Aircraft Emissions on Ozone Photochemistry and Radiative Forcing

by Giovanni Pitari, Daniela Iachetti, Glauco Di Genova, Natalia De Luca, Ole Amund Søvde, Øivind Hodnebrog, David S. Lee and Ling L. Lim

Atmosphere 2015, 6(6), 751-782; https://doi.org/10.3390/atmos6060751 - 2 Jun 2015

Cited by 23 | Viewed by 8229

Abstract

Three global chemistry-transport models (CTM) are used to quantify the radiative forcing (RF) from aviation NO_x emissions, and the resultant reductions in RF from coupling NO_x to aerosols via heterogeneous chemistry. One of the models calculates the changes due to aviation [...] Read more.

Three global chemistry-transport models (CTM) are used to quantify the radiative forcing (RF) from aviation NO_x emissions, and the resultant reductions in RF from coupling NO_x to aerosols via heterogeneous chemistry. One of the models calculates the changes due to aviation black carbon (BC) and sulphate aerosols and their direct RF, as well as the BC indirect effect on cirrus cloudiness. The surface area density of sulphate aerosols is then passed to the other models to compare the resulting photochemical perturbations on NO_x through heterogeneous chemical reactions. The perturbation on O₃ and CH₄ (via OH) is finally evaluated, considering both short- and long-term O₃ responses. Ozone RF is calculated using the monthly averaged output of the three CTMs in two independent radiative transfer codes. According to the models, column ozone and CH₄ lifetime changes due to coupled NO_x/aerosol emissions are, on average, +0.56 Dobson Units (DU) and −1.1 months, respectively, for atmospheric conditions and aviation emissions representative of the year 2006, with an RF of +16.4 and −10.2 mW/m² for O₃ and CH₄, respectively. Sulphate aerosol induced changes on ozone column and CH₄ lifetime account for −0.028 DU and +0.04 months, respectively, with corresponding RFs of −0.63 and +0.36 mW/m². Soot-cirrus forcing is calculated to be 4.9 mW/m². Full article

(This article belongs to the Special Issue Climate-Chemistry Interactions)

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847 KiB

Open AccessArticle

Chemical Composition of Water Soluble Inorganic Species in Precipitation at Shihwa Basin, Korea

by Seung-Myung Park, Beom-Keun Seo, Gangwoong Lee, Sung-Hyun Kahng and Yu Woon Jang

Atmosphere 2015, 6(6), 732-750; https://doi.org/10.3390/atmos6060732 - 25 May 2015

Cited by 38 | Viewed by 6755

Abstract

Weekly rain samples were collected in coastal areas of the Shihwa Basin (Korea) from June 2000 to November 2007. The study region includes industrial, rural, and agricultural areas. Wet precipitation was analyzed for conductivity, pH, Cl⁻, NO₃⁻, SO [...] Read more.

Weekly rain samples were collected in coastal areas of the Shihwa Basin (Korea) from June 2000 to November 2007. The study region includes industrial, rural, and agricultural areas. Wet precipitation was analyzed for conductivity, pH, Cl⁻, NO₃⁻, SO₄²⁻, Na⁺, K⁺, Mg²⁺, NH₄⁺, and Ca²⁺. The major components of precipitation in the Shihwa Basin were NH₄⁺, volume-weighted mean (VWM) of 44.6 µeq∙L⁻¹, representing 43% of all cations, and SO₄²⁻, with the highest concentration among the anions (55%) at all stations. The pH ranged from 3.4 to 7.7 with a VMM of 4.84. H⁺ was weakly but positively correlated with SO₄²⁻ (r = 0.39, p < 0.001) and NO₃⁻ (r = 0.38, p < 0.001). About 66% of the acidity was neutralized by NH₄⁺ and Ca²⁺. The Cl⁻/Na⁺ ratio of the precipitation was 37% higher than seawater Cl⁻/Na⁺. The high SO₄²⁻/NO₃⁻ ratio of 2.3 is attributed to the influence of the surrounding industrial sources. Results from positive matrix factorization showed that the precipitation chemistry in Shihwa Basin was influenced by secondary nitrate and sulfate (41% ± 1.1%), followed by sea salt and Asian dust, contributing 23% ± 3.9% and 17% ± 0.2%, respectively. In this study, the annual trends of SO₄²⁻ and NO₃⁻ (p < 0.05) increased, different from the trends in some locations, due to the influence of the expanding power generating facilities located in the upwind area. The increasing trends of SO₄²⁻ and NO₃⁻ in the study region have important implications for reducing air pollution in accordance with national energy policy. Full article

(This article belongs to the Special Issue Atmospheric Composition Observations)

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Atmosphere, Volume 6, Issue 6 (June 2015) – 7 articles , Pages 732-862

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