Pub Date : 2020-01-01DOI: 10.1080/16000889.2020.1721224
H. Mohammadzadeh, Javad Eskandari Mayvan, M. Heydarizad
Abstract Iran and Iraq face a water shortage crisis especially in the recent decade. Hence, the regions with high potential water resources are highly important to these countries. Precipitation sampling for 18O and 2H analyses was conducted in 10 stations in the west of Iran and 2 stations in the east of Iraq during this study. Studying precipitation and its moisture sources using the backward trajectories of the HYSPLIT model, developing seasonal meteoric water lines (MWLs), and simulating the spatial variations of stable isotopes in precipitation using stepwise regression yielded valuable results regarding the hydrometeorology of the study region. The precipitation moisture sources in the study region were determined using the backward trajectories of the HYSPLIT model. These backward trajectories demonstrated the domination of various moisture sources including the Mediterranean Sea, the Black Sea, the Red Sea, and also the Persian Gulf in different seasons as reflected in the seasonal MWLs. In addition to moisture sources, the effects of meteorological parameters (temperature and precipitation amount) on the stable isotope content of precipitation also showed a notable correlation (with R2 = 0.58 and 0.46, respectively). Surface water resources were also plotted on the developed seasonal MWLs, while some samples deviated from seasonal MWLs due to the evaporation effect.
{"title":"The effects of moisture sources and local parameters on the 18O and 2H contents of precipitation in the west of Iran and the east of Iraq","authors":"H. Mohammadzadeh, Javad Eskandari Mayvan, M. Heydarizad","doi":"10.1080/16000889.2020.1721224","DOIUrl":"https://doi.org/10.1080/16000889.2020.1721224","url":null,"abstract":"Abstract Iran and Iraq face a water shortage crisis especially in the recent decade. Hence, the regions with high potential water resources are highly important to these countries. Precipitation sampling for 18O and 2H analyses was conducted in 10 stations in the west of Iran and 2 stations in the east of Iraq during this study. Studying precipitation and its moisture sources using the backward trajectories of the HYSPLIT model, developing seasonal meteoric water lines (MWLs), and simulating the spatial variations of stable isotopes in precipitation using stepwise regression yielded valuable results regarding the hydrometeorology of the study region. The precipitation moisture sources in the study region were determined using the backward trajectories of the HYSPLIT model. These backward trajectories demonstrated the domination of various moisture sources including the Mediterranean Sea, the Black Sea, the Red Sea, and also the Persian Gulf in different seasons as reflected in the seasonal MWLs. In addition to moisture sources, the effects of meteorological parameters (temperature and precipitation amount) on the stable isotope content of precipitation also showed a notable correlation (with R2 = 0.58 and 0.46, respectively). Surface water resources were also plotted on the developed seasonal MWLs, while some samples deviated from seasonal MWLs due to the evaporation effect.","PeriodicalId":22320,"journal":{"name":"Tellus B: Chemical and Physical Meteorology","volume":"19 1","pages":"1 - 15"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91441287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/16000889.2020.1807245
Xiangdong Zheng, P. Ding, Z. Han, Chen Shen, Ke-xin Liu, Jie Tang, L. Bian
Abstract During January–March 2011, 29 atmospheric Δ14CO2 samples were measured along the R/V Xuelong cruise track from Zhongshan Station (69.37°S, 76.38°E; Antarctica) to Shanghai. The extent of fossil fuel contamination in the samples was evaluated by comparison with contemporary hemispheric-scale averages of Δ14CO2, together with transport analysis and consideration of the δ13CO2 levels in the samples. Generally, the Δ14CO2 levels along the route south to 40.67°S were lower than the hemispheric-scale average. Circumpolar deep water (CDW) upwelling, stratosphere–troposphere transport (STT), and regional transport associated with the Fukushima nuclear power plant (NPP) accident in Japan on 12 March 2011 were found to have influenced Δ14CO2 levels at the sampling sites. In comparison with the atmospheric Δ14CO2 level (45.7 ± 3.5‰ (1σ)) measured in the coastal region of East Antarctica, CDW upwelling caused reduction of ∼10‰ in Δ14CO2 in two cross sections: 62.0°–64.0°S along 74.0°E and 51.7°–54.0°S along 80.5°–84.0°E. Conversely, STT-enhanced Δ14CO2 was ∼7‰ (∼3‰) at Zhongshan (around 45.0°S). The linkage was supported by a certain Model-3/CMAQ simulation that indicated dispersion of radionuclides from the Fukushima NPP accident over the East Asian region, which explained the individual high Δ14CO2 (52‰) level on 29 March 2011 in Shanghai.
{"title":"Measurements of atmospheric Δ14CO2 along the R/V Xuelong cruise track from Zhongshan Station (Antarctica) to Shanghai","authors":"Xiangdong Zheng, P. Ding, Z. Han, Chen Shen, Ke-xin Liu, Jie Tang, L. Bian","doi":"10.1080/16000889.2020.1807245","DOIUrl":"https://doi.org/10.1080/16000889.2020.1807245","url":null,"abstract":"Abstract During January–March 2011, 29 atmospheric Δ14CO2 samples were measured along the R/V Xuelong cruise track from Zhongshan Station (69.37°S, 76.38°E; Antarctica) to Shanghai. The extent of fossil fuel contamination in the samples was evaluated by comparison with contemporary hemispheric-scale averages of Δ14CO2, together with transport analysis and consideration of the δ13CO2 levels in the samples. Generally, the Δ14CO2 levels along the route south to 40.67°S were lower than the hemispheric-scale average. Circumpolar deep water (CDW) upwelling, stratosphere–troposphere transport (STT), and regional transport associated with the Fukushima nuclear power plant (NPP) accident in Japan on 12 March 2011 were found to have influenced Δ14CO2 levels at the sampling sites. In comparison with the atmospheric Δ14CO2 level (45.7 ± 3.5‰ (1σ)) measured in the coastal region of East Antarctica, CDW upwelling caused reduction of ∼10‰ in Δ14CO2 in two cross sections: 62.0°–64.0°S along 74.0°E and 51.7°–54.0°S along 80.5°–84.0°E. Conversely, STT-enhanced Δ14CO2 was ∼7‰ (∼3‰) at Zhongshan (around 45.0°S). The linkage was supported by a certain Model-3/CMAQ simulation that indicated dispersion of radionuclides from the Fukushima NPP accident over the East Asian region, which explained the individual high Δ14CO2 (52‰) level on 29 March 2011 in Shanghai.","PeriodicalId":22320,"journal":{"name":"Tellus B: Chemical and Physical Meteorology","volume":"54 15 1","pages":"1 - 14"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80575529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/16000889.2020.1822063
K. Pilegaard, A. Ibrom
Abstract The carbon sequestration of plants through photosynthesis is responsible for removal of a substantial amount of the man-made CO2 emissions to the atmosphere. In recent years this so-called land-sink has removed about 30% of the man-made emissions to the atmosphere, with forests being the most important sinks. The land-sink is, however, vulnerable to changes in the environment, such as the atmospheric composition, climate change, and extreme events like storms and droughts. It is therefore important to study the effects of such change on terrestrial ecosystems to provide the basis for predicting the future of the sink. We here report the results of continuous CO2 flux measurements over a Danish beech forest during the years 1996–2019. Over the years the forest acted as a sink of CO2 with a net carbon sequestration ranging from about zero to 400 g C m–2 yr−1. We found significant trends in net ecosystem exchange (NEE) (increasing in absolute terms with 15 g C m–2 yr2), gross ecosystem exchange (GEE) (increasing with 25 g C m–2 yr–2), and ecosystem respiration (RE) (increasing with 10 g C m–2 yr–2). A prolonged growing season explained 73% of the increase in NEE. The increasing CO2 concentration in the atmosphere and a subsequent increase in photosynthetic capacity together with warming are the most likely main causes of the increased carbon uptake. The severe drought in the summer of 2018 resulted in a reduction of the annual NEE of 25%.
植物通过光合作用进行的碳固存负责清除大量人为排放到大气中的二氧化碳。近年来，这个所谓的陆地碳汇已经消除了大约30%的人为排放到大气中，其中森林是最重要的碳汇。然而，陆地汇很容易受到环境变化的影响，比如大气成分、气候变化以及风暴和干旱等极端事件。因此，重要的是研究这种变化对陆地生态系统的影响，为预测碳汇的未来提供依据。我们在这里报告了1996年至2019年期间丹麦山毛榉森林连续二氧化碳通量测量的结果。多年来，森林扮演着二氧化碳汇的角色，其净碳固存量约为0至400克/立方米/年。我们发现，净生态系统交换(NEE)(以15 g C m-2年的绝对值增加)、总生态系统交换(GEE)(以25 g C m-2年的绝对值增加)和生态系统呼吸(RE)(以10 g C m-2年的绝对值增加)呈显著趋势。生长季节延长解释了NEE增长的73%。大气中二氧化碳浓度的增加和随后光合作用能力的增加，再加上气候变暖，最有可能是碳吸收增加的主要原因。2018年夏季的严重干旱导致年度新能源效益减少了25%。
{"title":"Net carbon ecosystem exchange during 24 years in the Sorø Beech Forest – relations to phenology and climate","authors":"K. Pilegaard, A. Ibrom","doi":"10.1080/16000889.2020.1822063","DOIUrl":"https://doi.org/10.1080/16000889.2020.1822063","url":null,"abstract":"Abstract The carbon sequestration of plants through photosynthesis is responsible for removal of a substantial amount of the man-made CO2 emissions to the atmosphere. In recent years this so-called land-sink has removed about 30% of the man-made emissions to the atmosphere, with forests being the most important sinks. The land-sink is, however, vulnerable to changes in the environment, such as the atmospheric composition, climate change, and extreme events like storms and droughts. It is therefore important to study the effects of such change on terrestrial ecosystems to provide the basis for predicting the future of the sink. We here report the results of continuous CO2 flux measurements over a Danish beech forest during the years 1996–2019. Over the years the forest acted as a sink of CO2 with a net carbon sequestration ranging from about zero to 400 g C m–2 yr−1. We found significant trends in net ecosystem exchange (NEE) (increasing in absolute terms with 15 g C m–2 yr2), gross ecosystem exchange (GEE) (increasing with 25 g C m–2 yr–2), and ecosystem respiration (RE) (increasing with 10 g C m–2 yr–2). A prolonged growing season explained 73% of the increase in NEE. The increasing CO2 concentration in the atmosphere and a subsequent increase in photosynthetic capacity together with warming are the most likely main causes of the increased carbon uptake. The severe drought in the summer of 2018 resulted in a reduction of the annual NEE of 25%.","PeriodicalId":22320,"journal":{"name":"Tellus B: Chemical and Physical Meteorology","volume":"52 1","pages":"1 - 17"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84099112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/16000889.2019.1695349
M. Zanatta, H. Bozem, F. Köllner, J. Schneider, D. Kunkel, P. Hoor, Julia Perim de Faria, A. Petzold, U. Bundke, K. Hayden, R. Staebler, Hannes Schulz, A. Herber
Abstract The influence of shipping on air quality over the Southern Baltic Sea was investigated by characterizing the horizontal and vertical distribution of aerosols and trace gases using airborne measurements in the summer of 2015. Generally, continental and anthropogenic emissions affected the vertical distribution of atmospheric pollutants, leading to pronounced stratification in and above the marine boundary layer and controlling the aerosol extinction. Marine traffic along the shipping corridor “Kadet Fairway” in the Arkona Basin is shown to influence the presence and properties of both trace gases and aerosol particles in the lowest atmospheric layer. Total particle number concentration and NOy mixing ratio increased in the corridor plumes, relative to background, by a factor 1.55 and 3.45, respectively. Titration, triggered by the enhanced presence of nitrogen compounds, led to a median ozone depletion of 19% in the corridor plumes. The enforcement of the Sulphur Emission Control Area (SECA) might be responsible for the minor sulphur dioxide increase (20%) in the corridor plumes. Ship traffic caused a minor enhancement of black carbon mass concentration, estimated to be around 10%. The study of individual ship plumes indicated that ship emitted aerosol was substantially different from background aerosol: fresh ship exhaust was preferentially enriched in aerosol particles with diameters below 100 nm and in black carbon particles with core diameters above 300-400 nm. With the present work the impact of marine traffic on the concentration and properties of atmospheric components within the marine boundary layer over the open water of the Southern Baltic Sea is assessed with airborne observations for the first time. Due to the high uncertainty affecting the estimations of ship emissions, this dataset represents a valuable reference for the assessment of ship emission inventories and related environmental-climatic impacts on the Southern Baltic Sea.
{"title":"Airborne survey of trace gases and aerosols over the Southern Baltic Sea: from clean marine boundary layer to shipping corridor effect","authors":"M. Zanatta, H. Bozem, F. Köllner, J. Schneider, D. Kunkel, P. Hoor, Julia Perim de Faria, A. Petzold, U. Bundke, K. Hayden, R. Staebler, Hannes Schulz, A. Herber","doi":"10.1080/16000889.2019.1695349","DOIUrl":"https://doi.org/10.1080/16000889.2019.1695349","url":null,"abstract":"Abstract The influence of shipping on air quality over the Southern Baltic Sea was investigated by characterizing the horizontal and vertical distribution of aerosols and trace gases using airborne measurements in the summer of 2015. Generally, continental and anthropogenic emissions affected the vertical distribution of atmospheric pollutants, leading to pronounced stratification in and above the marine boundary layer and controlling the aerosol extinction. Marine traffic along the shipping corridor “Kadet Fairway” in the Arkona Basin is shown to influence the presence and properties of both trace gases and aerosol particles in the lowest atmospheric layer. Total particle number concentration and NOy mixing ratio increased in the corridor plumes, relative to background, by a factor 1.55 and 3.45, respectively. Titration, triggered by the enhanced presence of nitrogen compounds, led to a median ozone depletion of 19% in the corridor plumes. The enforcement of the Sulphur Emission Control Area (SECA) might be responsible for the minor sulphur dioxide increase (20%) in the corridor plumes. Ship traffic caused a minor enhancement of black carbon mass concentration, estimated to be around 10%. The study of individual ship plumes indicated that ship emitted aerosol was substantially different from background aerosol: fresh ship exhaust was preferentially enriched in aerosol particles with diameters below 100 nm and in black carbon particles with core diameters above 300-400 nm. With the present work the impact of marine traffic on the concentration and properties of atmospheric components within the marine boundary layer over the open water of the Southern Baltic Sea is assessed with airborne observations for the first time. Due to the high uncertainty affecting the estimations of ship emissions, this dataset represents a valuable reference for the assessment of ship emission inventories and related environmental-climatic impacts on the Southern Baltic Sea.","PeriodicalId":22320,"journal":{"name":"Tellus B: Chemical and Physical Meteorology","volume":"9 1","pages":"1 - 24"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76885239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/16000889.2020.1721967
N. Adhikari, Jing Gao, T. Yao, Yulong Yang, Di Dai
Abstract Precipitation stable isotopes (2H and 18O) are adequately understood on their climate controls in the Tibetan Plateau, especially the north of Himalayas via about 30 years’ studies. However, knowledge of controls on precipitation stable isotopes in Nepal (the south of Himalayas), is still far from sufficient. This study described the intra-seasonal and annual variations of precipitation stable isotopes at Kathmandu, Nepal from 10 May 2016 to 21 September 2018 and analysed the possible controls on precipitation stable isotopes. The enriched δD and δ18O values were identified during non-monsoon season and depleted values were found during monsoon season, showing remarkable intra-seasonal characteristics of monsoon influence. The local meteoric water line suggested a strong influence of evaporation during rainfall in non-monsoon season and significant impact of non-equilibrium processes on precipitation during monsoon season. Temperature–δ18O exhibited negative correlation for overall samples and showed no significant correlation in seasonal scales, which was attributed to the influence of monsoon moisture. The positive correlation was observed between δ18O and outgoing longwave radiation (OLR) in monsoon season, suggesting the significant impact of convective activity on temporal variations of precipitation stable isotopes. During April, and May of 2016 and 2017, variation of precipitation stable isotopes are probably related with the mixing of multi-moisture combined with the westerlies transport. Our study suggested that the moisture transport processes are the main controls of precipitation stable isotopes at Kathmandu.
{"title":"The main controls of the precipitation stable isotopes at Kathmandu, Nepal","authors":"N. Adhikari, Jing Gao, T. Yao, Yulong Yang, Di Dai","doi":"10.1080/16000889.2020.1721967","DOIUrl":"https://doi.org/10.1080/16000889.2020.1721967","url":null,"abstract":"Abstract Precipitation stable isotopes (2H and 18O) are adequately understood on their climate controls in the Tibetan Plateau, especially the north of Himalayas via about 30 years’ studies. However, knowledge of controls on precipitation stable isotopes in Nepal (the south of Himalayas), is still far from sufficient. This study described the intra-seasonal and annual variations of precipitation stable isotopes at Kathmandu, Nepal from 10 May 2016 to 21 September 2018 and analysed the possible controls on precipitation stable isotopes. The enriched δD and δ18O values were identified during non-monsoon season and depleted values were found during monsoon season, showing remarkable intra-seasonal characteristics of monsoon influence. The local meteoric water line suggested a strong influence of evaporation during rainfall in non-monsoon season and significant impact of non-equilibrium processes on precipitation during monsoon season. Temperature–δ18O exhibited negative correlation for overall samples and showed no significant correlation in seasonal scales, which was attributed to the influence of monsoon moisture. The positive correlation was observed between δ18O and outgoing longwave radiation (OLR) in monsoon season, suggesting the significant impact of convective activity on temporal variations of precipitation stable isotopes. During April, and May of 2016 and 2017, variation of precipitation stable isotopes are probably related with the mixing of multi-moisture combined with the westerlies transport. Our study suggested that the moisture transport processes are the main controls of precipitation stable isotopes at Kathmandu.","PeriodicalId":22320,"journal":{"name":"Tellus B: Chemical and Physical Meteorology","volume":"110 1","pages":"1 - 17"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80846100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/16000889.2020.1821512
C. Menares, L. Gallardo, M. Kanakidou, R. Seguel, N. Huneeus
Abstract Despite the decline in partially (PM10) and fully (PM2.5) inhalable particles observed in recent decades, Santiago in Chile shows high levels of particle and ozone pollution. Attainment plans have emphasized measures aimed at curbing primary and, to some extent, secondary particles, but little attention has been paid to photochemical pollution. Nevertheless, ozone hourly mixing ratios in Eastern Santiago regularly exceed 110 ppbv in summer, and in winter maximum mixing ratios often reach 90 ppbv. Moreover, the sum of ozone and nitrogen dioxide shows an increasing trend of more than 3.5 ppbv per decade at 5 out of 8 stations. This trend is driven by increasing NO2, possibly associated with increasing motorization but also with changes in photochemistry. To estimate the fraction of secondary particles in PM2.5 and due to the lack of long-term speciation data for particles, we use carbon monoxide as a proxy of primary particles and ozone daily maxima as a proxy for secondary particle formation. We find a growing fraction of secondary particles due to an increase in the oxidizing capacity of Santiago’s atmosphere. This stresses the need for new curbing measures to tackle photochemical pollution. This is particularly needed in the context of a changing climate.
{"title":"Increasing trends (2001–2018) in photochemical activity and secondary aerosols in Santiago, Chile","authors":"C. Menares, L. Gallardo, M. Kanakidou, R. Seguel, N. Huneeus","doi":"10.1080/16000889.2020.1821512","DOIUrl":"https://doi.org/10.1080/16000889.2020.1821512","url":null,"abstract":"Abstract Despite the decline in partially (PM10) and fully (PM2.5) inhalable particles observed in recent decades, Santiago in Chile shows high levels of particle and ozone pollution. Attainment plans have emphasized measures aimed at curbing primary and, to some extent, secondary particles, but little attention has been paid to photochemical pollution. Nevertheless, ozone hourly mixing ratios in Eastern Santiago regularly exceed 110 ppbv in summer, and in winter maximum mixing ratios often reach 90 ppbv. Moreover, the sum of ozone and nitrogen dioxide shows an increasing trend of more than 3.5 ppbv per decade at 5 out of 8 stations. This trend is driven by increasing NO2, possibly associated with increasing motorization but also with changes in photochemistry. To estimate the fraction of secondary particles in PM2.5 and due to the lack of long-term speciation data for particles, we use carbon monoxide as a proxy of primary particles and ozone daily maxima as a proxy for secondary particle formation. We find a growing fraction of secondary particles due to an increase in the oxidizing capacity of Santiago’s atmosphere. This stresses the need for new curbing measures to tackle photochemical pollution. This is particularly needed in the context of a changing climate.","PeriodicalId":22320,"journal":{"name":"Tellus B: Chemical and Physical Meteorology","volume":"23 1","pages":"1 - 18"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78974470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/16000889.2020.1801305
Lærke Sloth Nielsen, M. Bilde
Abstract This work addresses the production of aerosol particles from bursting of air bubbles at the water-air interface. Experiments were performed in a laboratory system designed to minimize bubble interactions. Air bubbles of an equivalent spherical radius of ∼3 mm were generated in both real and artificial seawater at temperatures of 0 and 19 °C respectively. Particle concentrations were measured and used to derive particle production per bursting bubble. The particle production in surface seawater from the Bay of Aarhus showed remarkably strong sensitivity to temperature, with ∼40 particles per bursting bubble at 19 °C compared to ∼2300 particles per bubble at 0 °C. A similar effect was observed for bubbles bursting in NaCl solutions. In contrast, the effect of temperature on particle production from artificial seawater was minimal. Further experiments including exclusion of selected inorganic components from artificial seawater point to magnesium and calcium ions as key role players on the effect of temperature. Experiments adding varying amounts of the weak surfactant succinic acid to sodium chloride solutions showed that the influence of temperature on particle production can also be modulated by organic molecules. A complex interplay between inorganic and organic constituents seems to determine the response of particle production to temperature in real seawater. Our study demonstrates that temperature can have a very large (orders of magnitude) effect on the production of particles formed from bubbles bursting at the liquid/air interface, and that chemical composition of the liquid is a controlling parameter for the magnitude of this effect.
{"title":"Exploring controlling factors for sea spray aerosol production: temperature, inorganic ions and organic surfactants","authors":"Lærke Sloth Nielsen, M. Bilde","doi":"10.1080/16000889.2020.1801305","DOIUrl":"https://doi.org/10.1080/16000889.2020.1801305","url":null,"abstract":"Abstract This work addresses the production of aerosol particles from bursting of air bubbles at the water-air interface. Experiments were performed in a laboratory system designed to minimize bubble interactions. Air bubbles of an equivalent spherical radius of ∼3 mm were generated in both real and artificial seawater at temperatures of 0 and 19 °C respectively. Particle concentrations were measured and used to derive particle production per bursting bubble. The particle production in surface seawater from the Bay of Aarhus showed remarkably strong sensitivity to temperature, with ∼40 particles per bursting bubble at 19 °C compared to ∼2300 particles per bubble at 0 °C. A similar effect was observed for bubbles bursting in NaCl solutions. In contrast, the effect of temperature on particle production from artificial seawater was minimal. Further experiments including exclusion of selected inorganic components from artificial seawater point to magnesium and calcium ions as key role players on the effect of temperature. Experiments adding varying amounts of the weak surfactant succinic acid to sodium chloride solutions showed that the influence of temperature on particle production can also be modulated by organic molecules. A complex interplay between inorganic and organic constituents seems to determine the response of particle production to temperature in real seawater. Our study demonstrates that temperature can have a very large (orders of magnitude) effect on the production of particles formed from bubbles bursting at the liquid/air interface, and that chemical composition of the liquid is a controlling parameter for the magnitude of this effect.","PeriodicalId":22320,"journal":{"name":"Tellus B: Chemical and Physical Meteorology","volume":"27 1","pages":"1 - 10"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77081929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/16000889.2020.1770509
Lu Wang, Yu Liu, Qiang Li, Huiming Song, Qiufang Cai, Changfeng Sun, Congxi Fang, Ruoshi Liu
Abstract Tree-ring stable oxygen isotope (δ18OTR) demonstrates the enormous potential for revealing hydrological climate changes and large-scale atmospheric circulations. Here, we established the 210-year δ18OTR chronology of Pinus tabulaeformis Carr. in Baotou, southwest Inner Mongolia, North China. The regional precipitation δ18O (δ18OP) and June-July-August relative humidity (RHJJA) were the two dominant environmental factors controlling the δ18OTR changes. Since the 1930s, the increasing δ18OTR values in the study region reflected the drying trend due to reducing precipitation and increasing temperature. The δ18OTR series in Baotou generally exhibited stronger correlations with three Indian summer monsoon (ISM) indexes than three East Asian summer monsoon (EASM) indexes during 1948–2009 AD. However, the δ18OTR record also significantly correlated with one EASM index. These results indicated that the Asian summer monsoon played an essential role in modifying the δ18OTR values, and the ISM possibly had more considerable influence compared with the EASM. We also found that the δ18OTR record had a higher correlation with the central-Pacific El Niño-Southern Oscillation (ENSO) than that with eastern-Pacific ENSO, probably because of the more substantial impact of the central-Pacific ENSO on the ISM.
{"title":"A 210-year tree-ring δ18O record in North China and its relationship with large-scale circulations","authors":"Lu Wang, Yu Liu, Qiang Li, Huiming Song, Qiufang Cai, Changfeng Sun, Congxi Fang, Ruoshi Liu","doi":"10.1080/16000889.2020.1770509","DOIUrl":"https://doi.org/10.1080/16000889.2020.1770509","url":null,"abstract":"Abstract Tree-ring stable oxygen isotope (δ18OTR) demonstrates the enormous potential for revealing hydrological climate changes and large-scale atmospheric circulations. Here, we established the 210-year δ18OTR chronology of Pinus tabulaeformis Carr. in Baotou, southwest Inner Mongolia, North China. The regional precipitation δ18O (δ18OP) and June-July-August relative humidity (RHJJA) were the two dominant environmental factors controlling the δ18OTR changes. Since the 1930s, the increasing δ18OTR values in the study region reflected the drying trend due to reducing precipitation and increasing temperature. The δ18OTR series in Baotou generally exhibited stronger correlations with three Indian summer monsoon (ISM) indexes than three East Asian summer monsoon (EASM) indexes during 1948–2009 AD. However, the δ18OTR record also significantly correlated with one EASM index. These results indicated that the Asian summer monsoon played an essential role in modifying the δ18OTR values, and the ISM possibly had more considerable influence compared with the EASM. We also found that the δ18OTR record had a higher correlation with the central-Pacific El Niño-Southern Oscillation (ENSO) than that with eastern-Pacific ENSO, probably because of the more substantial impact of the central-Pacific ENSO on the ISM.","PeriodicalId":22320,"journal":{"name":"Tellus B: Chemical and Physical Meteorology","volume":"19 1","pages":"1 - 15"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87332265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/16000889.2020.1778968
Yulan Zhang, Shi-chang Kang, T. Gao, M. Sprenger, T. Dou, Wei-Qing Han, Qi Zhang, Shiwei Sun, W. Du, Pengfei Chen, Junming Guo, Xiaoqing Cui, M. Sillanpää
Abstract Dissolved organic carbon (DOC) plays an important role in the carbon cycle, radiative forcing, and biogeochemistry in cryospheric regions. In this study, concentrations, light-absorption properties and bioavailability of DOC from snow cover in Alaska were characterized. Results indicated that average concentrations of DOC in snow of Alaska (0.17 − 0.30 mg L−1) were lower than that found in Asian mountainous glaciers, but higher that found from polar regions snow. No significant trend of DOC was observed during April to May in 2017 due to the short term study; while the vertical variations generally showed a little higher values in the surface snow than that in the sub-surface snow. An obvious characteristic of DOC light-absorbance in snow between the wavelength of 300 and 700 nm indicated the mass absorption cross section of DOC at 365 nm (MACDOC365) was 0.32 ± 0.24 and 0.37 ± 0.32 m2 g−1 for the snow cover at Barrow site (Arctic Ocean coast) and the other Alaskan regions, respectively. The MACDOC365 values increased especially during snow melting, indicating the DOC with high MAC values were prone to retain in snow. The proportion of radiative forcing caused by DOC relative to that by black carbon in snow was approximately 2.3%, indicating that DOC in snow should be considered during the accelerated melt of snow cover. The bioavailability experiment of DOC in snow indicated that DOC may be an important bioavailable source for proglacial and coastal ecosystems in Alaskan Arctic regions. Using backward air mass trajectory analysis, we suggested that DOC deposited in snow at Barrow primarily originates from marine or terrestrial air mass, but the specific contribution of different sources cannot be quantified without data related to the DOC’s chemical composition and carbon isotopic signatures. This study highlighted the climatic implications of DOC in snow in the Arctic regions.
{"title":"Dissolved organic carbon in Alaskan Arctic snow: concentrations, light-absorption properties, and bioavailability","authors":"Yulan Zhang, Shi-chang Kang, T. Gao, M. Sprenger, T. Dou, Wei-Qing Han, Qi Zhang, Shiwei Sun, W. Du, Pengfei Chen, Junming Guo, Xiaoqing Cui, M. Sillanpää","doi":"10.1080/16000889.2020.1778968","DOIUrl":"https://doi.org/10.1080/16000889.2020.1778968","url":null,"abstract":"Abstract Dissolved organic carbon (DOC) plays an important role in the carbon cycle, radiative forcing, and biogeochemistry in cryospheric regions. In this study, concentrations, light-absorption properties and bioavailability of DOC from snow cover in Alaska were characterized. Results indicated that average concentrations of DOC in snow of Alaska (0.17 − 0.30 mg L−1) were lower than that found in Asian mountainous glaciers, but higher that found from polar regions snow. No significant trend of DOC was observed during April to May in 2017 due to the short term study; while the vertical variations generally showed a little higher values in the surface snow than that in the sub-surface snow. An obvious characteristic of DOC light-absorbance in snow between the wavelength of 300 and 700 nm indicated the mass absorption cross section of DOC at 365 nm (MACDOC365) was 0.32 ± 0.24 and 0.37 ± 0.32 m2 g−1 for the snow cover at Barrow site (Arctic Ocean coast) and the other Alaskan regions, respectively. The MACDOC365 values increased especially during snow melting, indicating the DOC with high MAC values were prone to retain in snow. The proportion of radiative forcing caused by DOC relative to that by black carbon in snow was approximately 2.3%, indicating that DOC in snow should be considered during the accelerated melt of snow cover. The bioavailability experiment of DOC in snow indicated that DOC may be an important bioavailable source for proglacial and coastal ecosystems in Alaskan Arctic regions. Using backward air mass trajectory analysis, we suggested that DOC deposited in snow at Barrow primarily originates from marine or terrestrial air mass, but the specific contribution of different sources cannot be quantified without data related to the DOC’s chemical composition and carbon isotopic signatures. This study highlighted the climatic implications of DOC in snow in the Arctic regions.","PeriodicalId":22320,"journal":{"name":"Tellus B: Chemical and Physical Meteorology","volume":"74 1","pages":"1 - 19"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86286950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/16000889.2020.1823733
M. Menoud, C. van der Veen, B. Scheeren, Huilin Chen, Barbara Szénási, R. Morales, I. Pison, P. Bousquet, D. Brunner, T. Röckmann
Abstract Despite the importance of methane for climate change mitigation, uncertainties regarding the temporal and spatial variability of the emissions remain. Measurements of CH4 isotopic composition are used to partition the relative contributions of different emission sources. We report continuous isotopic measurements during 5 months at the Lutjewad tower (north of the Netherlands). Time-series of χ(CH4), δ13C-CH4, and δD-CH4 in ambient air were analysed using the Keeling plot method. Resulting source signatures ranged from −67.4 to −52.4‰ vs V-PDB and from −372 to −211‰ vs V-SMOW, for δ13C and δD respectively, indicating a prevalence of biogenic sources. Analysis of isotope and wind data indicated that (i) emissions from off-shore oil and gas platforms in the North Sea were not detected during this period, (ii) CH4 from fossil fuel related sources was usually advected from the east, pointing towards the Groningen gas field or regions further east in Germany. The results from two atmospheric transport models, CHIMERE and FLEXPART-COSMO, using the EDGAR v4.3.2 and TNO-MACC III emission inventories, reproduce χ(CH4) variations relatively well, but the isotope signatures were over-estimated by the model compared to the observations. Accounting for geographical variations of the δ13C signatures from fossil fuel emissions improved the model results significantly. The difference between model and measured isotopic signatures was larger when using TNO-MACC III compared to EDGAR v4.3.2 inventory. Uncertainties in the isotope signatures of the sources could explain a significant fraction of the discrepancy, thus a better source characterisation could further strengthen the use of isotopes in constraining emissions.
{"title":"Characterisation of methane sources in Lutjewad, The Netherlands, using quasi-continuous isotopic composition measurements","authors":"M. Menoud, C. van der Veen, B. Scheeren, Huilin Chen, Barbara Szénási, R. Morales, I. Pison, P. Bousquet, D. Brunner, T. Röckmann","doi":"10.1080/16000889.2020.1823733","DOIUrl":"https://doi.org/10.1080/16000889.2020.1823733","url":null,"abstract":"Abstract Despite the importance of methane for climate change mitigation, uncertainties regarding the temporal and spatial variability of the emissions remain. Measurements of CH4 isotopic composition are used to partition the relative contributions of different emission sources. We report continuous isotopic measurements during 5 months at the Lutjewad tower (north of the Netherlands). Time-series of χ(CH4), δ13C-CH4, and δD-CH4 in ambient air were analysed using the Keeling plot method. Resulting source signatures ranged from −67.4 to −52.4‰ vs V-PDB and from −372 to −211‰ vs V-SMOW, for δ13C and δD respectively, indicating a prevalence of biogenic sources. Analysis of isotope and wind data indicated that (i) emissions from off-shore oil and gas platforms in the North Sea were not detected during this period, (ii) CH4 from fossil fuel related sources was usually advected from the east, pointing towards the Groningen gas field or regions further east in Germany. The results from two atmospheric transport models, CHIMERE and FLEXPART-COSMO, using the EDGAR v4.3.2 and TNO-MACC III emission inventories, reproduce χ(CH4) variations relatively well, but the isotope signatures were over-estimated by the model compared to the observations. Accounting for geographical variations of the δ13C signatures from fossil fuel emissions improved the model results significantly. The difference between model and measured isotopic signatures was larger when using TNO-MACC III compared to EDGAR v4.3.2 inventory. Uncertainties in the isotope signatures of the sources could explain a significant fraction of the discrepancy, thus a better source characterisation could further strengthen the use of isotopes in constraining emissions.","PeriodicalId":22320,"journal":{"name":"Tellus B: Chemical and Physical Meteorology","volume":"46 1","pages":"1 - 20"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80956438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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