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Obstetrik ve jinekolojide sonografi, prensipler ve klinik uygulamalar
Kitap Bölümü

Kitap Bölümü
Kaynak :
DSpace Makaleler
Dergi:
ATMOSPHERIC RESEARCH
Yayıncı:
ATMOSPHERIC RESEARCH
Yazar(lar) :
Atıl YÜKSEL
Konu :
Sağlık Bilimleri, Tıp, Klinik Tıp (MED)
Yıl :
2021
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
Kaydet Alıntıla
Anahtar Kelimeler : Sağlık Bilimleri, Tıp, Klinik Tıp (MED), Kitapta Bölüm
Sınıflandırma :
2
Impact of climate variability on precipitation in the Upper Euphrates-Tigris Rivers Basin of Southeast Turkey
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Dergi:
Atmospheric Research
Yayıncı:
Elsevier Science Inc
Yazar(lar) :
Kadri Yurekli
Konu :
Precipitation trend analysis, Euphrates-Tigris basin, Mann-Kendal test, Theil-Sen Slope estimator, Percent change
Yıl :
2015
Atmospheric Research
Yayıncı Web Sitesi
Kaydet Alıntıla
This paper evaluates changes in precipitation in the upper the Euphrates-Tigris basin enclosing the whole area of Southeastern Anatolian Project (GAP), which is the largest investment for regional development in the history of Turkey and the fourth largest irrigation project in the world. For this purpose, the analyses are based on new data sequences formed by summing up monthly precipitation of 19 stations in the study area at seven different time scales. The Mann-Kendal (MK) and Theil-Sen Slope estimator (TSE) statistics to detect the direction and magnitude of an available monotonic trend in any given data, respectively, were used for the statistical analysis of the new data sequences. Besides, the sequential version of Mann-Kendal rank test (SVMK) to detect the approximate starting point of a trend was also applied the data set of the stations with significant monotonic trend. The monotonic trend was detected at 63% of the stations (12 of 19 stations) for the different time scales at 5% significance level. The stations with positive and negative or insignificant precipitation trends were scattered in the different parts of the basin. The significant trends were found in six stations with respect to the critical value (+/- 2.33) from the standard normal distribution for one-sided hypothesis at 1% significance level. The TSE results for 12 stations with monotonic trend at different time scales varied from -236 mm to 2.51 mm per year. Of the six stations, the maximum decrease (-72.5%) and increase (166.9%) in the percent change (PC) were determined in Agri and Bitlis stations, respectively. The approximate starting points of upward and downward trend for Kills, Simak, Agri, Elazig, Bitlis and Siirt stations were at about 1980, 1979, 1987, 1986, 1984 and 1965 with respect to the SVMK test, respectively. According to the results obtained from the previous studies, the river basin is affected by the North Atlantic Oscillation (NAO) and global warming. Therefore, it is very likely that the NAO and global warming have been contributing to changes in precipitation of the river basin. (C) 2014 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : Precipitation trend analysis, Euphrates-Tigris basin, Mann-Kendal test, Theil-Sen Slope estimator, Percent change, article
Cilt: 154
ISSN: 0169-8095
Sınıflandırma :
3
Trends and changes in tropical and summer days at the Adana Sub-Region of the Mediterranean Region, Southern Turkey
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Dergi:
ATMOSPHERIC RESEARCH
Yayıncı:
ATMOSPHERIC RESEARCH
Yazar(lar) :
Turkan Bayer Altin , Belma Barak
Konu :
Yerbilimleri, Mühendislik ve Teknoloji, METEOROLOJİ VE ATMOSFER BİLİMLERİ, Atmosfer Bilimleri ve Meteoroloji Mühendisliği, Temel Bilimler (SCI)
Yıl :
2021
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
Kaydet Alıntıla
In this study, the long-term variability and trends of the annual and seasonal numbers of summer and tropical days of the Adana Sub-region were investigated using nonlinear and linear trend detection tests for the period 1960-2014 at 14 meteorological stations. The results suggest that the annual number of summer and tropical days was generally below the long-term average through to the end of the 1980s. In particular, positive anomaly values could be observed at all stations between the years 1993-2014. With respect to the Kruskal-Wallis homogeneity test, the significant breaking date was 1993. The rapid rise of the annual number of summer (tropical) days after this year led to the inversion of the negative trends observed from 1987 to 1992 into positive ones. The increasing trend is statistically significance at 0.01 level in Yumurtalik, Mersin and Antalya for the annual number of summer and tropical days. Dortyol, Iskenderun and Elbistan were significance at 0.01 level for tropical days. The largest positive anomalies of the summer of 2010 are observed in coastal vicinity (Mersin, Yumurtalik and Iskenderun). This indicates that these settlements underwent a long-term warm period and thermal conditions due to increasing temperatures in the spring and summer months. The same conditions are found in high inner areas (Goksun and Elbistan) for tropical days. It is noticed that a tendency for greater warming occurred at stations located above 1000 m in the sub-region. The average number of warm days will increase 2-days per 100-years in southern part of the sub-region. The increasing trend in summer temperatures can be considered a potential risk, notably for human health and for economic and crop losses in the Adana Sub-region, including cukurova, one of the most important agriculture areas of Turkey.
Anahtar Kelimeler : Yerbilimleri, Mühendislik ve Teknoloji, METEOROLOJİ VE ATMOSFER BİLİMLERİ, Atmosfer Bilimleri ve Meteoroloji Mühendisliği, Temel Bilimler (SCI), Makale

ISSN: 0169-8095
Sınıflandırma :
4
Intercomparison of the expected change in the temperature and the precipitation retrieved from CMIP6 and CMIP5 climate projections: A Mediterranean hot spot case, Turkey
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Dergi:
Atmospheric Research
Yayıncı:
Elsevier
Yazar(lar) :
Soner Çağatay Bağçacı , İsmail Yücel , Eren Düzenli , Mustafa Tuğrul Yılmaz
Konu :
Climate Change Hotspot, Coupled Model Intercomparison Project, Global Climate Model, Turkey Climate
Yıl :
2021
Atmospheric Research
Yayıncı Web Sitesi
Kaydet Alıntıla
The performances of a large number of Global Circulation Models (GCMs) belonging to the latest release the Coupled Model Intercomparison Project phase 6 (CMIP6) in comparison with its predecessor CMIP5 are evaluated for monthly precipitation and temperature over Turkey (i.e. climate change hotspot). The ensemble of best top four models from both CMIP simulations is also used to investigate the future climate change under medium and high emissions for short, medium, and long terms. Results show CMIP6 products outperform CMIP5 in terms of accuracy statistics, particularly for precipitation. Overall, CMIP6 indicate less intermodel variability, implying the climate signal obtained via CMIP6 is improved relative to CMIP5. The CMIP6 reduce the error in precipitation and temperature 11% and 6%, respectively while increasing the correlation 13% for precipitation. Correlation is not changed for temperature. The substantial success of CMIP6 mainly manifests itself in the winter precipitation and autumn temperature. A slightly warmer (up to 0.35 ?C) climate from the CMIP6 is projected while precipitation change in mean precipitation decline is about 2.5% smaller for CMIP6. However, precipitation changes in maximum decline and increase are more noticeable for CMIP6, addressing the better resolving for future climate variability. The summer warming (up to 6.5 ?C) and drying (up to -40%) towards autumn spread across the country. The increased precipitation projection in the winter and spring over the east of the Black Sea Region and north-east of Anatolia may further increase the flood risks in the area.
Anahtar Kelimeler : Climate Change Hotspot, Coupled Model Intercomparison Project, Global Climate Model, Turkey Climate, article
Cilt: 256
ISSN: 0169-8095
Sınıflandırma :
5
Aksaray İli rekabet Gücü Analizi ve Gelişim Stratejileri
Kitap Bölümü

Kitap Bölümü
Kaynak :
DSpace Makaleler
Dergi:
ATMOSPHERIC RESEARCH
Yayıncı:
ATMOSPHERIC RESEARCH
Yazar(lar) :
Mehmet Barca , Mahmut HIZIROĞLU , Abdulkadir Hızıroğlu
Konu :
Sosyal ve Beşeri Bilimler, İşletme, Ekonomi ve İş, Sosyal Bilimler (SOC)
Yıl :
2021
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
Kaydet Alıntıla
Anahtar Kelimeler : Sosyal ve Beşeri Bilimler, İşletme, Ekonomi ve İş, Sosyal Bilimler (SOC), Kitapta Bölüm
Sınıflandırma :
6
A general Look on Behavioral Genetic Evidence's Impact on the Adjudication of Criminal Behavior
Bildiri Serisi

Bildiri Serisi
Kaynak :
DSpace Makaleler
Dergi:
ATMOSPHERIC RESEARCH
Yayıncı:
ATMOSPHERIC RESEARCH
Yazar(lar) :
Hızır Aslıyürek , Esma Cansu Çevik , Filiz Ekim ÇEVİK , Faruk Asicioglu
Yıl :
2021
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
Kaydet Alıntıla
Anahtar Kelimeler : Bildiri
Sınıflandırma :
Hukuk %75
İş Kanunu %47
7
ÇOCUK ENFEKSİYON HASTALIKLARI
Kitap Bölümü

Kitap Bölümü
Kaynak :
DSpace Makaleler
Dergi:
ATMOSPHERIC RESEARCH
Yayıncı:
ATMOSPHERIC RESEARCH
Yazar(lar) :
BAHAR CALISKAN , Ayper SOMER
Konu :
Klinik Tıp (MED), Tıp, Sağlık Bilimleri
Yıl :
2021
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
Kaydet Alıntıla
Anahtar Kelimeler : Klinik Tıp (MED), Tıp, Sağlık Bilimleri, Kitapta Bölüm
Sınıflandırma :
8
The regional prediction model of PM10 concentrations for Turkey
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Dergi:
Atmospheric Research
Yayıncı:
Elsevier Science Inc
Yazar(lar) :
Nevin Güler , Öznur Güneri İşçi
Konu :
The Regional Prediction Model, Fuzzy C-Auto Regressive Model, Fuzzy Clustering, Auto Regressive Model, Air Pollutants
Yıl :
2016
Atmospheric Research
Yayıncı Web Sitesi
Kaydet Alıntıla
This study is aimed to predict a regional model for weekly PM10 concentrations measured air pollution monitoring stations in Turkey. There are seven geographical regions in Turkey and numerous monitoring stations at each region. Predicting a model conventionally for each monitoring station requires a lot of labor and time and it may lead to degradation in quality of prediction when the number of measurements obtained from any omonitoring station is small. Besides, prediction models obtained by this way only reflect the air pollutant behavior of a small area. This study uses Fuzzy C-Auto Regressive Model (FCARM) in order to find a prediction model to be reflected the regional behavior of weekly PM10 concentrations. The superiority of FCARM is to have the ability of considering simultaneously PM10 concentrations measured monitoring stations in the specified region. Besides, it also works even if the number of measurements obtained from the monitoring stations is different or small. In order to evaluate the performance of FCARM, FCARM is executed for all regions in Turkey and prediction results are compared to statistical Autoregressive (AR) Models predicted for each station separately. According to Mean Absolute Percentage Error (MAPE) criteria, it is observed that FCARM provides the better predictions with a less number of models. (C) 2016 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : The Regional Prediction Model, Fuzzy C-Auto Regressive Model, Fuzzy Clustering, Auto Regressive Model, Air Pollutants, article
Cilt: 180
ISSN: 0169-8095
Sınıflandırma :
9
Application of Cellular Neural Network (CNN) to the Prediction of Missing Air Pollutant Data.
Dergi Makalesi

Dergi Makalesi
Open Access
Kaynak :
DSpace Makaleler
Dergi:
Atmospheric Research Volume
Yayıncı:
Atmospheric Research Volume
Yazar(lar) :
Ü. A. ŞAHİN , C. BAYAT , Osman Nuri UÇAN
Konu :
Cellular Neural Network
Yıl :
2011
Atmospheric Research Volume
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Anahtar Kelimeler : Cellular Neural Network, Article
Sınıflandırma :
10
Dry deposition, concentration and gas/particle partitioning of atmospheric carbazole
Araştırma Makalesi

Araştırma Makalesi
Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Dergi:
ATMOSPHERIC RESEARCH
Yazar(lar) :
S Siddik Cindoruk , Yuecel Tasdemir , Fatma Esen
Yıl :
2010
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
The atmospheric concentrations and dry deposition of carbazole were measured to present the temporal changes, gas/particle partitioning and magnitude of fluxes. Atmospheric samples were collected from July 2004 to May 2005 at four different sites in Bursa, Turkey. The average total (gas and particulate) carbazole concentrations were 7.6 +/- 9.9 ng m(-3) in Gulbahoe (Residential), 1.1 +/- 1.2 ng m(-3) in BUTAL (Traffic), 33 +/- 5.0 ng m(-3) in BOID (industrial), and 1.2 +/- 0.7 ng m(-3) in the Uludag University Campus (UU) (Suburban). Experimental gas/particle partition coefficient (K-P) was determined using the study results and compared with K-P values calculated from octanol-air and soot-air+octanol partitioning models. Total dry deposition fluxes of carbazole were 290 +/- 484 ng m(-2) d(-1) in BUTAL and 72 +/- 67 ng m(-2) d(-1) in the UU Campus. Particulate phase dry deposition velocities were 0.81 +/- 0.78 cm s(-1) and 0.90 +/- 1.53 cm s(-1) for BUTAL and the UU Campus, respectively. On the other hand, gas-phase mass transfer coefficients were calculated to be 0.34 +/- 0.29 cm s(-1) and 026 +/- 0.17 cm s(-1) for BUTAL and the UU Campus, respectively. (C) 2009 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.atmosres.2009.10.010
Sayi :95
issue :4
Sayfa :379-385
Sınıflandırma :
11
Origin and source regions of PM10 in the Eastern Mediterranean atmosphere
Araştırma Makalesi

Araştırma Makalesi
Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Dergi:
ATMOSPHERIC RESEARCH
Yazar(lar) :
Nilguen Kubilay , Nikos Mihalopoulos , Mustafa Kocak
Yıl :
2009
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
A set of daily PM10 (n=281) samples collected from April 2001 to April 2002 at a rural site (Erdemli), located on the coast of the Eastern Mediterranean, were analyzed applying Mass Closure (MC), absolute principal factor analysis (APFA) and Positive Matrix Factorization (PMF) to determine source contributions. The results from the three techniques were compared to identify the similarities and differences in the sources and source contributions. Source apportionment analysis indicated that PM10 were mainly originated from natural sources (sea salt +crustal approximate to 60%) whilst secondary aerosols and residual oil burning accounted for approximately 20% and 10% of the total PM10 mass, respectively. Calculations for sulfate showed that on average 8% and 12% of its total concentration were originated from sea salt and biogenic emissions, respectively. However, the contribution by biogenic emissions may reach up to a maximum of similar to 40% in the summer Potential Source Contribution Function (PSCF) analysis for identification of source regions showed that the Saharan desert was the main source area for crustal components. For secondary aerosol components the analysis revealed one source region, (i.e. the south-Eastern Black Sea), whereas for residual oil, Western Europe and the western Balkans areas were found to be the main Source regions. (C) 2009 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.atmosres.2009.01.005
Sayi :92
issue :4
Sayfa :464-474
Sınıflandırma :
12
Volatile organic compounds in suburban Ankara atmosphere, Turkey: Sources and variability
Araştırma Makalesi

Araştırma Makalesi
Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Dergi:
ATMOSPHERIC RESEARCH
Yazar(lar) :
Gurdal Tuncel , Mihriban Civan , Sema Yurdakul
Yıl :
2013
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
In this study, concentrations of approximately 30 VOCs were measured, between January and June 2008 at a university campus in Ankara. Concentrations of measured VOCs are lower than corresponding concentrations reported for other cities in literature. Average concentrations of the measured VOCs ranged from 0.04 to 7.89 mu g m(-3). Benzene (2.18 mu g m(-3)), toluene (7.89 mu g m(-3)), ethylbenzene (0.85 mu g m(-3)) and xylenes (2.62 mu g m(-3)) (BTEX) were found as a major organics in suburban Ankara atmosphere. The measured VOCs also show well defined diurnal and weekday weekend cycles. Toluene-to-benzene ratio (TT/B) suggested that non-traffic sources can be important during summer months. The m,p-xylene-to-ethylbenzene ratio (X/E) pointed to transport of organic compounds from high-emission districts of the city. Positive matrix factorization applied to data revealed four sources, including gasoline exhaust, solvent evaporation, diesel emissions and a local laboratory source, contributing to VOC concentrations. Strengths of these sources, particularly solvent source, on total VOC concentrations showed seasonal differences. Source contributions on light and heavy VOCs were also different. (C) 2012 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.atmosres.2012.09.015
Sayi :120
Sayfa :298-311
Sınıflandırma :
Çevre %100
Çevre %97
13
Concentrations and sources of PAHs at three stations in Istanbul, Turkey
Araştırma Makalesi

Araştırma Makalesi
Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Dergi:
ATMOSPHERIC RESEARCH
Yazar(lar) :
M Talat Odman , Edip Avsar , Jaemeen Baek , Burcak Kaynak , Kadir Alp , Asude Hanedar
Yıl :
2011
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
The chemical mass balance model was applied to atmospheric Polycyclic Aromatic Hydrocarbons (PAHs) in Istanbul, Turkey. A total of 326 airborne samples were collected and analyzed for 16 PAHs and Total Suspended Particles (TSP) in the September 2006 December 2007 period at three monitoring stations: Yildiz, DMO (urban sites) and Kilyos (rural site). The total average PAH concentrations were 100.66 +/- 61.26, 84.63 +/- 46.66 and 25.12 +/- 13.34 ng m(-3) and the TSP concentrations were 101.16 +/- 53.22, 152.31 +/- 99.12, 49.84 +/- 18.58 mu g m(-3) for Yildiz. DMO and Kilyos stations respectively. At all the sites, the lighter compounds were the most abundant, notably Nap, AcPy and PA. The average correlation values between TSP and total heavier PAH were greater than 0.5 for Yildiz and DMO stations. The patterns of PAH and TSP concentrations showed spatial and temporal variations. PAH concentrations were evaluated for the PAH contribution from four sources (diesel engines, gasoline engines, natural gas combustion, and coal + wood burning). Vehicle emissions appear to be the major source with contributions of 61.2%, 63.3% and 54.1% for Yildiz. DMO and Kilyos stations respectively. Seasonal and yearly variations had different trends for all sites. (C) 2010 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.atmosres.2010.11.017
Sayi :99
issue :3-4
Sayfa :391-399
Sınıflandırma :
14
Trace elements in urban and suburban rainfall, Mersin, Northeastern Mediterranean
Araştırma Makalesi

Araştırma Makalesi
Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Dergi:
ATMOSPHERIC RESEARCH
Yazar(lar) :
Sermin Ornektekin , Turkan Ozsoy
Yıl :
2009
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
Spatial/temporal variabilities of rainwater constituents are examined based on soluble/insoluble trace elements, pH and electrical conductivity measurements in rainfall sampled during December 2003-May 2005 at two urban and two suburban sites in Mersin, an industrialized city of 850,000 inhabitants on the southern coast of Turkey. In the analyses, backward air mass trajectories for rainy days were used in addition to factor analyses, enrichment factors, phase distributions and correlations between trace elements. The pH varied from 4.8 to 8.5 with an average value of 6.2, reflecting a mainly alkaline regime. Mean concentrations of trace elements collected from urban and suburban sites are spatially variable. Based on the overall data, total concentrations of trace elements were ordered as Ca>Na>Fe>Al>Mg>K>Zn>Mn>Sr>Pb>Ni>Cr>Ba>Cu>Co>Cd. Mainly terrigeneous (Ca, Fe, Al) and, to a lesser extent, sea salt particles (Na, Mg) were shown to be the major source of trace elements. Excluding major cations, the solubilities of trace elements were found to be ordered as Sr>Zn>Ba>Mn>Cu>Ni>Cr>Fe>Al, confirming the lower solubility of crustal elements. Cd, Co and Pb were excluded from the above evaluation because of the low numbers of soluble samples allowing quantitative measurements. The solubilities of Al. Fe, Mn and particularly of Ni were found to be considerably lower than those reported for various sites around the world, most likely due to the effect of pH. During the entire sampling period, a total of 28 dust transport episodes associated with 31 red rain events were identified. Extremely high mean concentration ratios of Al (8.2), Fe (14.4) and Mn (13.1) were observed in red rain, compared to normal rain. The degree of this enhancement displayed a decrease from crustal to anthropogenic origin elements and the lowest enhancements were found for anthropogenic origin elements of Zn and Cd (both having a ratio of 1.1). Aerosol dust was found to be the main source of almost all analyzed elements in Mersin precipitation, regardless that they are crustal or anthropic derived elements. The magnitude of crustal source contribution to trace element budget of precipitation was at its highest levels for crustal originated elements, most probably due to much higher scavenging ratios of crustal elements compared to anthropogenic ones. (C) 2009 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.atmosres.2009.05.017
Sayi :94
issue :2
Sayfa :203-219
Sınıflandırma :
15
A case study for Saharan dust transport over Turkey via RegCM4.1 model
Araştırma Makalesi

Araştırma Makalesi
Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Dergi:
ATMOSPHERIC RESEARCH
Yazar(lar) :
Fabien Solmon , Marc Mallet , Luca Pozzoli , Alper Unal , Tayfun Kindap , Tugba Agacayak
Yıl :
2015
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
The purpose of this study is to investigate a dust transport episode using atmospheric 3D modeling, satellite data, and in-situ observations. 3D simulations have been used to determine the aerosol optical properties and direct radiative effects of dust particles. In this study, the number of daily exceedances due to dust transport is estimated and, performance of RegCM4.1 model tested quantitatively with the aid of AOD data from AERONET network and PM10) ground measurements. The impact of dust on radiation estimated by the model for the 4-day period. PM10, values for Istanbul for the period between 2004-2010, and Marmara and Aegean Region for March 2008 provided by the Turkish Ministry of Environment were used to select an important episode. Exceedance days were evaluated according to the BSC-DREAM8b model output. We have used the RegCM4.1 model to further investigate the Saharan dust transport in the selected episode 21-24 March 2008. First, observed daily mean PM10 concentrations reach up to 180 mu g/m(3) in Marmara Region and 160 mu g/m(3) in Aegean Region, respectively. According to the RegCM4.1 model outputs, station Erdemli presents the highest AOD on 23rd March 2008, around 12, which is found to be highest than AERONET observations (ADD of 0.7). In parallel, daily mean AOD in Marmara Region is around 1.0 on the same day. Corresponding simulated column burden is about 1000 mg/m(2) in Marmara Region and 750 mg/m(2) in Aegean Region, respectively. In terms of radiative effect, daily mean shortwave (all-sky) radiative effect at surface (ToA) is -62 W/m(2) (-29 W/m(2)) in Marmara and -71 W/m(2) (-33 W/m(2)) in Aegean Region, respectively. In parallel, longwave all-sky direct forcing at surface (ToA) is + 7 W/m(2) and (+4 W/m(2)) in Marmara, +11 W/m(2) (+4 W/m(2)) in Aegean Region. (C) 2014 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.atmosres.2014.09.012
Sayi :153
Sayfa :392-403
Sınıflandırma :
16
Metallic composition and source apportionment of fine and coarse particles using positive matrix factorization in the southern Black Sea atmosphere
Araştırma Makalesi

Araştırma Makalesi
Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Dergi:
ATMOSPHERIC RESEARCH
Yazar(lar) :
Ridvan Kirmaz , Abdullah Zararsiz , Pinar Suren , Omar Alagha , Ferhat Karaca , Gurdal Tuncel , Lokman Hakan Tecer
Yıl :
2012
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
In this study, coarse- (PM2.5-10) and fine (PM2.5) fraction aerosol samples were collected using a dichotomous sampler, and their metallic composition (Mg, Al, Ti, Ca, Cr, Cu, Fe, K, Mn, Ni, Pb, and Zn) were analyzed using X-ray fluorescence. The average crustal enrichment factor (EFc) values of Pb, Cu, SO42-. and Zn are greater than 10 for both coarse- and fine-fraction aerosols, which indicates that anthropogenic sources account for the concentrations of these four elements in both the fractions. In this study, positive matrix factorization (PMF) was used for the source apportionment of PM2.5 mass in the Zonguldak atmosphere. A total of six factors were identified, which can be interpreted as either emission sources or physically meaningful factors. The goodness of the six-factor solution for the PMF model was tested by comparing the measured and the modeled PM2.5 masses. An excellent agreement was found between the measured and the modeled fine masses, which indicates that the six-factor-PMF solution adopted in this study accurately accounts for the observed PM2.5 mass in the city of Zonguldak, the city is located at the middle of the Black Sea coasts of Turkey. (C) 2012 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.atmosres.2012.06.016
Sayi :118
Sayfa :153-169
Sınıflandırma :
17
Gas-particle partitioning of polycyclic aromatic hydrocarbons (PAHs) in an urban traffic site in Eskisehir, Turkey
Araştırma Makalesi

Araştırma Makalesi
Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Dergi:
ATMOSPHERIC RESEARCH
Yazar(lar) :
Akif Ari , Eftade O Gaga
Yıl :
2011
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
Gas and particle-phase ambient air samples were collected at a traffic site in Eskisehir over a six-month period between January and October 2006. Gas/particle concentrations of 15 PAHs were determined by analyzing integrated glass fiber and polyurethane foam samples. On average, 66% of the total concentrations of PAHs were found in the gas-phase in heating and 69% in the non-heating period samples. Heating period PAH concentrations were found to be 7 to 8 times greater than concentrations in non-heating period samples. Multiple linear regression analysis was carried out to determine the effect of meteorological parameters on measured individual PAH concentrations. Temperature, wind speed and wind direction explained 43% (dibenzo[a,h]anthracene and benzo[a]pyrene) to 78% (phenanthrene) of the variability in atmospheric PAH concentrations. Results of the multiple linear regression analysis indicated that temperature and wind speed were statistically significant factors for the measured concentrations of PAHs. Gas-particle partitioning coefficients, (K-p) and particle-phase fractions (Phi) of PAHs, were correlated with supercooled vapor pressures (P-L(o)). Application of non-linear fitting for Phi versus log P-L(o) plots was found to be more robust than linear logarithmic regressions of log K-p versus log P-L(o) plots. Particle-phase fractions (Phi) for each PAH were also calculated using octanol-air and soot-air partitioning models. Soot model resulted better predictions of Phi for fluorene, phenanthrene, anthracene, fluoranthene and pyrene. Both two models yielded very similar particle-phase fractions having very close results to experimentally obtained Phi values for the rest of PAHs measured. (C) 2010 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.atmosres.2010.10.013
Sayi :99
issue :2
Sayfa :207-216
Sınıflandırma :
18
Seasonal and spatial variations of atmospheric trace elemental deposition in the Aliaga industrial region, Turkey
Araştırma Makalesi

Araştırma Makalesi
Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Dergi:
ATMOSPHERIC RESEARCH
Yazar(lar) :
Abdurrahman Bayram , Mustafa Odabasi , Tolga Elbir , Hasan Altiok , Yetkin Dumanoglu , Melik Kara
Yıl :
2014
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
Atmospheric bulk deposition (wet + dry deposition) samples (n = 40) were collected concurrently at ten sites in four seasons between June 2009 and April 2010 in the Aliaga heavily industrialized region, Turkey, containing a number of significant air pollutant sources. Analyses of trace elements were carried out using inductively coupled plasma-mass spectrometry (ICP-MS). While there were significant differences in the particulate matter (PM) deposition fluxes among the sampling sites, seasonal variations were not statistically significant (Kruskal-Wallis test, p <0.05). Both PM deposition and elemental fluxes were increased at the sampling sites in the vicinity of industrial activities. The crustal elements (i.e., Ca, Mg) and some anthropogenic elements (such as Fe, Zn, Mn, Pb, Cu, and Cr) were high, and the highest fluxes were mostly measured in summer and winter seasons. The enrichment factor (EF) and principal component analysis (PCA) was applied to the data to determine the possible sources in the study area. High EF values were obtained for the anthropogenic elements such as Ag, Cd, Zn, Pb, Cu and Sb. The possible sources were identified as anthropogenic sources (i.e., iron-steel production) (45.4%), crustal and re-suspended dust (27.1%), marine aerosol (7.9%), and coal and wood combustion (8.2%). Thus, the iron-steel production and its related activities were found to be the main pollutant sources for this region. (C) 2014 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.atmosres.2014.06.009
Sayi :149
Sayfa :204-216
Sınıflandırma :
19
Bulk precipitation chemistry at the forest and forest village
Araştırma Makalesi

Araştırma Makalesi
Open Access
Kaynak :
Aperta - TÜBİTAK Açık Arşivi
Dergi:
ATMOSPHERIC RESEARCH
Yazar(lar) :
Mehmet Ozcan , Suleyman Ozhan , Betul Uygur , Ibrahim Yurtseven , Yusuf Serengil , Kamil Sengonul , Ferhat Gokbulak
Yıl :
2013
ATMOSPHERIC RESEARCH
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
The objectives of this study were to characterize and compare selected physical and chemical properties of precipitation in a broadleaf mixed forest and a village located in the same forest in order to determine the influence of the village on the atmospheric environmental quality of the forest ecosystem. Bulk precipitation samples were collected weekly from October 2005 to July 2011. Precipitation samples were analyzed for pH, electrical conductivity (EC), turbidity, total suspended particles (TSP), total alkalinity (CaCO3), alkalinity (HCO3-), chloride (Cl-), total hardness (CaCO3), Ca hardness (CaCO3), calcium (Ca2+), magnesium (Mg2+), organic matter, total nitrogen (N), sodium (Na+), potassium (K+), nitrate (NO3)(-), phosphate (PO4)(3-), iron (Fe), aluminum (Al), ammonium (NH4)(+), and sulfate (SO4)(2-). The precipitation samples from forest and forest village were significantly different from each other for EC, total alkalinity (CaCO3), HCO3-, Ca hardness (CaCO3), Ca2+, total N, K+, NO3-, and NH4+. Regardless of the study sites, PO43- and Mg2+ were dominant anion and cation, respectively. The orders of cation and anion concentrations were similar for both study sites and they were in descending order of Mg2+ > Ca2+ > Na+ > K+ > NH4+ > Fe > Al > H+ and PO43- > HCO3- > SO42- > Cl- > NO3-, respectively. Overall average monthly values of precipitation characteristics did not show significant difference between months except for pH, EC, total alkalinity (CaCO3), and HCO3-. Significant correlations were found between SO42- and pH, Ca2+, NH4+ and between NO3- and NH4+ for the precipitation event at the forest site. Both study sites had pH values higher than 5.6 due to the neutralization of SO42- and NO3- by NH4+ and Ca2+. Significant correlation coefficients found between the study sites for the same precipitation parameter indicated that both study sites were under the influence of the same emission sources. (C), 2013 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.atmosres.2013.08.005
Sayi :134
Sayfa :161-174
Sınıflandırma :
20
Instability indices for severe weather forecasting in West Africa
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Atmospheric Research
Yayıncı:
Elsevier
Yazar(lar) :
K. Oduro-Afriyie , D.O. Adefolalu
Yıl :
1993
Atmospheric Research
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Two instability indices are developed to forecast the occurrence of severe weather phenomena in West Africa. The indices, I7 and I5, are defined as the difference between the equivalent potential temperatures at 1000 hPa and 700 hPa and at 1000 hPa and 500 hPa respectively. Monthly averaged data for the period 1960–1970 were used to find a relation between the indices and areal mean precipitation in the northern zone (7.5°N–20°N) and the southern zone (0°–7.5°N) of West Africa. A clear relation existed in the northern zone but not in the southern zone. Daily data for 1975 and 1976 were used to develop the indices for Kano, Nigeria, as a single station case study. Various ranges of the indices were found to effectively predict the occurence of precipitation, thunderstorm, squall line, and thunderstorm with squall line. In general, severe weather was most prevalent in Kano when 0 ⩽ I5 ⩽ 20.0K (6.0 ⩽ I7 ⩽ 15.0K). Résumé On a établi deux indices d'instabilité destinés à la prévision des perturbations en Afrique de l'Quest. Ces indices, I7 et I5, sont dédinis comme étant la différence entre les températures potentielles équivalentes respectivement á 1000 et 700 hPa et á 1000 et 500 hPa. On utilise les données moyennes mensuelle pour la période 1960–1970 afin d'établir une relation entre les indices et la précipitation moyenne dans les régions nord (7,5°N–20°N) et sud (0°–7,5°N) de l'Afrique de l'Ouest. On trouve une relations nette dans la région nord mais pas dans la région sud. On utilise les données de 1975 et 1976 afin de déterminer les indices pour Kano, Nigéria, en tant qu'étude de cas relatif á une station unique. On trouve effectivement des plages d'indice relatives á des situations de précipitation, orage, ligne des grains et orage avec ligne de grains. En général, les perturbations violentes á Kano associées á des indices I5 compris entre 0 et 20,0 K et I7 compris entre 6,0 et 15,0 K.
DOI : 10.1016/0169-8095(93)90054-r
ISSN: 0169-8095
Sayı: 1
Cilt: 30
Sayfa: 51-68
Sınıflandırma :
21
In memoriam Walter F.^Hitschfeld (1922–1986)
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Atmospheric Research
Yayıncı:
Elsevier
Yazar(lar) :
R.G. Soulage
Yıl :
1987
Atmospheric Research
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
DOI : 10.1016/0169-8095(87)90008-1
ISSN: 0169-8095
Sayı: 2
Cilt: 21
Sayfa: 183-184
22
Signatures of large peak current lightning strokes during an unusually intense sprite-producing thunderstorm in southern England
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Atmospheric Research
Yayıncı:
Elsevier BV
Yazar(lar) :
Andrea Pizzuti , Jonathan M. Wilkinson , Serge Soula , Janusz Mlynarczyk , Ivana Kolmašová , Ondřej Santolík , Robert Scovell , Alec Bennett , Martin Füllekrug
Yıl :
2021
Atmospheric Research
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
During the night of 26–27 May 2017, a mesoscale convective system (MCS) rapidly developed over Cornwall and Devon in the South West of England, producing about 3500 lightning flashes in 3 h and 23 sprites. The MCS-type storm was characterised by a circular shape with a size of about 52,000 km2 (cloud top temperature lower than - 40 °C) and a local minimum in the CG flash rate (~15 min−1), when most of the sprites were observed. The mean intensity of the sprite parent CG strokes was exceptionally high in this case (+170 kA), while the associated charge moment changes ranged from 600 to 2000C km. Two identical detectors, located at different sites in southern England, measured the quasi-static displacement currents induced on metallic electrodes when exposed to the changing atmospheric electric field produced by the storm's discharges. A series of coincident large amplitude short-peak transients, some of which associated with the sprite-producing strokes, were recorded on these detectors. A multi-instrumental analysis of the lightning events producing transient current “spikes” on the electrodes revealed a significant bias towards large peak currents exceeding 100 kA, but only a minor dependence on the impulse charge moment change (iCMC) for those associated with the sprites. We suggest that the current spikes may be induced by a coupling with the electromagnetic impulse radiated by intense lightning discharges. The ease in discriminating such signatures makes the method suitable for monitoring the occurrence of powerful lightning, potentially associated with night-time transient luminous events (TLEs), thereby avoiding the limitations inherent to optical observations and radio noise affecting other receivers.
DOI : 10.1016/j.atmosres.2020.105357
Anahtar Kelimeler : Lightning, Thunderstorm, Natural hazards, TLEs, Sprites, Elves, Halos, EMP, Superbolts
ISSN: 0169-8095
Cilt: 249
Sayfa: 105357
23
Contents Volume 79, 2006
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Atmospheric Research
Yayıncı:
Elsevier
Yıl :
2006
Atmospheric Research
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
DOI : 10.1016/s0169-8095(06)00013-5
ISSN: 0169-8095
Sayı: 3-4
Cilt: 79
Sayfa: 327-328
Sınıflandırma :
24
Contents vol. 20, 1986
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Atmospheric Research
Yayıncı:
Elsevier
Yıl :
1986
Atmospheric Research
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
DOI : 10.1016/0169-8095(86)90033-5
ISSN: 0169-8095
Sayı: 2-4
Cilt: 20
Sayfa: 335-336
Sınıflandırma :
25
Editorial
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Atmospheric Research
Yayıncı:
Elsevier
Yazar(lar) :
Norihiko Fukuta , Paul E. Wagner
Yıl :
1994
Atmospheric Research
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
DOI : 10.1016/0169-8095(94)90029-9
ISSN: 0169-8095
Sayı: 1-3
Cilt: 31
Sayfa: 1
Sınıflandırma :
26
Retrieval of cloud optical and microphysical properties from multispectral radiances
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Atmospheric Research
Yayıncı:
Elsevier
Yazar(lar) :
Lothar Schüller , Wolfgang Armbruster , Jürgen Fischer
Yıl :
2000
Atmospheric Research
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
This paper describes measurements made with a high spectral resolution radiometer (OVID) during the EUCREX mission 206, for the retrieval of optical and microphysical cloud properties. The retrieval algorithm is based on the calculation of the radiative transfer through a cloudy atmosphere with a numerical model based on the Matrix Operator method. The simulation of the spectral radiances at the flight level in 942 spectral channels fits precisely the actual spectra measured with OVID, with a good description of the absorption and scattering features. A number of 1486 simulations, based on a plane parallel model of clouds with various combinations of cloud optical thickness and droplet effective radius, form the lookup table of reflectance values that are used to retrieve these parameters from the measured spectra. The OVID measurements performed along five legs flown by the DLR-F20 aircraft during the EUCREX mission 206 have been processed. The retrieved values of optical thickness and effective radius are compared in the EUCREX summary paper to estimates derived from in situ measurements and values retrieved from airborne lidar and radiometric measurements as well as from satellite radiometric measurements.
DOI : 10.1016/s0169-8095(00)00055-7
Anahtar Kelimeler : Cloud radiative properties, Remote sensing retrieval techniques
ISSN: 0169-8095
Sayı: 1
Cilt: 55
Sayfa: 35-45
Sınıflandırma :
27
Interdecadal component variation characteristics in heavy winter snow intensity in North-Eastern China and its response to sea surface temperatures
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Atmospheric Research
Yayıncı:
Elsevier
Yazar(lar) :
Chun-Yu Zhao , Yi-He Fang , Yong Luo , Ji Wang
Yıl :
2016
Atmospheric Research
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Based on daily precipitation data from 208 weather stations, monthly NCEP/NCAR reanalysis data, and sea surface temperature data reconstructed by NOAA between 1961 and 2012, the heavy winter snow intensity in North-Eastern China was defined; its spatiotemporal variation characteristics were analyzed; the physical mechanisms of the relations between key sea surface temperature (SST) regions and heavy winter snow intensity were studied. Results showed that, in terms of temporal variation characteristics: heavy winter snow intensity in North-Eastern China has been rising, with obvious interdecadal variations during the study interval. In terms of spatial variation characteristics: the first empirical orthogonal function (EOF) mode of the interdecadal component in heavy winter snow intensity showed consistent anomaly characteristics throughout the region; the second mode exhibited opposite variation characteristics between the south and north; and the third mode exhibited opposite variation characteristics between the northwest and southeast. In terms of physical mechanisms underlying the effects of SST on heavy winter snow intensity, the key SST region of the first EOF mode was the Oyashio, the interdecadal component of the autumn Oyashio SST was abnormally high, which corresponded to a higher winter 500 hPa height field in the northern section of the North Pacific. This condition led to a blocking situation and was associated with a weaker East Asian winter monsoon (EAMW), which resulted in a stronger interdecadal component of heavy winter snow intensity and vice versa. The second mode was closely related to the Pacific Decadal Oscillation (PDO): the interdecadal component of the autumn PDO was abnormal, which induced the teleconnection pattern of the winter Pacific-North America (PNA) pattern. The PNA pattern may have been related to the second EOF mode through its association with the Mongolian high.
DOI : 10.1016/j.atmosres.2016.05.016
Anahtar Kelimeler : North-Eastern China, Heavy winter snow intensity, Interdecadal component, Oyashio SST, PDO, PNA
ISSN: 0169-8095
Cilt: 180
Sayfa: 165-177
Sınıflandırma :
28
Model Output Statistics to improve severe storms prediction over Western Sahel
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Atmospheric Research
Yayıncı:
Elsevier
Yazar(lar) :
O.S. Idowu , C.J.deW Rautenbach
Yıl :
2009
Atmospheric Research
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
The recent increasing trend in the severity of floods, especially across West Africa has been due largely to severe storm outbreaks which are complex and difficult to predict. Most of the weather forecasting centers in Africa now use numerical weather prediction (NWP) model outputs to predict the occurrence and severity of these storms. However, several studies have shown that NWP models and their forecasts are subject to errors and biases because of the complex atmospheric uncertainties and the currently limited knowledge of the mathematical formulation of the atmospheric physics and dynamics. The incorporation of statistical techniques is therefore useful and has indeed become a necessary component of improving NWP model products. Model Output Statistics (MOS), for example, use large multiple regression equations to provide a statistical relationship between the forecast output of NWP models and the observed variables. This study investigates the implementation of the MOS equations generated for Western Sahel (WS), required to correct forecast biases and errors from the 20 km × 20 km resolution Limited Area Model over Africa (Africa LAM) developed by the United Kingdom Meteorological Office (UK Met Office). Daily observed rainfall from January 2005 to December 2006, of 36 selected meteorological stations regionally distributed across the WS as well as the T + 24 h rainfall forecasts from the Africa LAM over the same period were retrieved and analyzed. Results indicated about 76% improvement to the original Africa LAM rainfall forecasts by the MOS method over the southern region of the WS during July–August–September—the period when severe storm activities are highly probable. Results also showed a consistently smaller root mean squared error (RMSE) values from the MOS-corrected rainfall forecasts when compared with the RMSEs from the original Africa LAM rainfall forecasts for all the seasons and regions of the WS.
DOI : 10.1016/j.atmosres.2008.10.035
Anahtar Kelimeler : Severe storms, Numerical weather prediction, Model Output Statistics, MOS equations
ISSN: 0169-8095
Sayı: 1-3
Cilt: 93
Sayfa: 419-425
Sınıflandırma :
29
Characterization, sources, and light absorption of fine organic aerosols during summer and winter at an urban site
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Atmospheric Research
Yayıncı:
Elsevier
Yazar(lar) :
Seungshik Park , Se-Chang Son , Sangil Lee
Yıl :
2018
Atmospheric Research
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
In this study, the 24-h PM2.5 samples were collected from an urban site in Korea during summer and winter. The collected samples were analyzed for organic carbon (OC), elemental carbon (EC), water-soluble OC, humic-like substances (HULIS), and ionic species. Furthermore, in-situ measurements of PM2.5 aerosol absorption coefficients were made by using a dual-spot multi-wavelength Aethalometer. Primary traffic emissions and secondary formation were the major contributors to the HULIS concentration during summer. Furthermore, biomass burning (BB) contributed to HULIS concentration to a certain extent. During winter, the HULIS with higher OC/EC ratio (6.4) were strongly associated with BB and secondary formation, while the HULIS with lower OC/EC ratio (2.9) was mainly attributed to secondary formation and, to a certain extent, primary combustion sources. Light absorption by brown carbon (BrC) was significantly enhanced in the near-ultraviolet and visible spectral regions and exhibited strong spectral dependence. Ambient BrC absorption was estimated to account for 2.1–16.6% and 5.9–29.3% of the total aerosol absorption during summer and winter, respectively. The average values of absorption Ångström exponent (AAE) in the wavelength range of 370–660 nm for light-absorbing BrC aerosols were estimated to be 4.0 and 4.4 during summer and winter, respectively. This study demonstrates that the AAE values for BrC can be derived from multi-wavelength Aethalometer data without filter sampling and detailed laboratory analysis.
DOI : 10.1016/j.atmosres.2018.06.017
Anahtar Kelimeler : Brown carbon, Humic-like substances, Aerosol light absorption, Dual-spot Aethalometer, Absorption Ångström exponent
ISSN: 0169-8095
Cilt: 213
Sayfa: 370-380
Sınıflandırma :
30
Molecular composition of secondary organic aerosol from styrene under different NO and humidity conditions
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Atmospheric Research
Yayıncı:
Elsevier BV
Yazar(lar) :
ShanShan Yu , Long Jia , YongFu Xu , YuePeng Pan
Yıl :
2022
Atmospheric Research
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Styrene is highly reactive in the atmosphere, which has been identified as a hazardous air pollutant by the Clean Air Act, and as an important secondary organic aerosol (SOA) precursor. In this study, the SOA formation from styrene under different NOx and relative humidity (RH) conditions were explored in an indoor chamber. The chemical composition of SOA was characterized using a Fourier transform infrared spectroscopy (FTIR) and a modified atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The results show that the SOA yields decrease from 11.4% to 7.2% at about 70 μg m−3 SOA as RH increases from 8.5% to 62.4% in the H2O2 system; the SOA yields decrease from 1.1% to 0.7% at about 10 μg m−3 SOA as RH increases from 8.4% to 60.9% in the NOx system. In the H2O2 system, C7 and C8 series compounds are major components of SOA at both RHs. The total signal ratio of less oxidized C7 and C8 compounds (nO < 4) to the total SOA at 8.8% RH is 2.2 times higher than that at 63.3% RH. The OSc values of SOA were determined to be −0.2 at 8.8% RH and 0.04 at 63.3% RH based on MS data. It is proposed that high RH can accelerate the heterogeneous uptake of H2O2 onto particles and promote the further oxidation of less oxidized compounds in the particle phase. In the NOx system, SOA formation is significantly suppressed by the competitive reaction of RO2 with NO. The FTIR and MS results show that the main composition of SOA is organonitrates. At 8.3% RH, OH, O3 and NO3 are oxidants in the styrene-NOx irritation system. Among these oxidants, NO3 plays a minor role due to its photolysis. While at 60.9% RH, SOA formation from O3 is significantly inhibited by the reaction of stabilized Criegee intermediates (SCIs) with H2O, and SOA from the NO3 pathway is suppressed by the heterogeneous uptake of N2O5 to humid particles.
DOI : 10.1016/j.atmosres.2021.105950
Anahtar Kelimeler : Styrene, Secondary organic aerosol, Relative humidity, Chemical composition, Smog chamber
ISSN: 0169-8095
Cilt: 266
Sayfa: 105950

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