Pub Date : 2001-04-01DOI: 10.1016/S1465-9972(00)00050-7
D.C. Parashar, Prabhat K. Gupta, Chhemendra Sharma
The annual sink strengths of soils under rabi and kharif crops, forests, pastures and long fallow areas have been estimated to be 0.11, 0.34, 0.01 and 0.05 Tg yr−1, respectively for the atmospheric methane. The total annual sink provided by Indian soils is 0.51 Tg yr−1 and is about 4% of the total annual methane emission attributed to anthropogenic sources in India.
经估算,稻田、森林、牧场和长休耕区土壤的年吸收强度分别为0.11、0.34、0.01和0.05 Tg yr - 1。印度土壤提供的年总碳汇为0.51 Tg yr - 1,约占印度人为来源的年甲烷排放总量的4%。
{"title":"Estimate of methane uptake potential by Indian soils","authors":"D.C. Parashar, Prabhat K. Gupta, Chhemendra Sharma","doi":"10.1016/S1465-9972(00)00050-7","DOIUrl":"10.1016/S1465-9972(00)00050-7","url":null,"abstract":"<div><p><span>The annual sink strengths of soils under rabi and kharif crops, forests, pastures and long fallow areas have been estimated to be 0.11, 0.34, 0.01 and 0.05 Tg yr</span><sup>−1</sup>, respectively for the atmospheric methane. The total annual sink provided by Indian soils is 0.51 Tg yr<sup>−1</sup><span> and is about 4% of the total annual methane emission attributed to anthropogenic sources in India.</span></p></div>","PeriodicalId":100235,"journal":{"name":"Chemosphere - Global Change Science","volume":"3 2","pages":"Pages 171-174"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1465-9972(00)00050-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74151429","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 : 2001-01-01DOI: 10.1016/S1465-9972(00)00044-1
R.R. Sharpe , L.A. Harper , J.D. Simmons
Gaseous methane (CH4) emissions were determined during the winter and summer from `farrow-to-finish' (FF) swine production houses and during the summer from a `farrow-to-wean' (FW) house in 1998 in the coastal plains of North Carolina. The houses were instrumented with sensors to determine cycling of the individual forced-ventilation fans. Laser spectrometry was used to measure CH4 concentration differences between the intake and exhaust points of the houses. Differences in CH4 concentrations were combined with fan operation data to calculate CH4 fluxes from the houses. During the cold winter measurement period, CH4 fluxes averaged 6.9 g in the FF house. During summer measurement periods, CH4 fluxes were much greater and averaged 33 and 46 g from the FF and FW houses, respectively. The much larger emissions during the summer than winter, indicate that CH4 house emissions were primarily from fresh feces and the underground storage/wash pits containing lagoon effluent; and not directly from the animals since temperature would have little affect on direct animal emission. Emission factors based on animal units (au) of 454 kg animal−1 were much greater at the FW farm with a pull-plug waste management system (7–8 day wash cycle) than at the FF farm with a periodic flush system (8 h wash cycle).
气态甲烷(CH4)排放量于1998年冬季和夏季在北卡罗来纳州沿海平原的“产犊至肥育”(FF)猪舍和夏季在“产犊至断奶”(FW)猪舍进行了测定。房屋配备了传感器,以确定单个强制通风机的循环。采用激光光谱法测定了房屋进排气点之间的CH4浓度差异。CH4浓度的差异与风机运行数据相结合,计算了房屋的CH4通量。在寒冷的冬季测量期间,FF室内CH4通量平均为6.9 g CH4动物−1d−1。在夏季测量期间,CH4通量要大得多,FF和FW的CH4动物- 1d - 1平均分别为33和46 g。夏季甲烷排放量明显大于冬季,表明甲烷主要来自新鲜粪便和含泻湖污水的地下储洗坑;而且不是直接来自动物,因为温度对动物的直接排放几乎没有影响。采用拔塞式废物管理系统(7-8天洗涤周期)的FW养殖场以454 kg动物单位(au)为基础的排放因子要比采用定期冲洗系统(8小时洗涤周期)的FF养殖场大得多。
{"title":"Methane emissions from swine houses in North Carolina","authors":"R.R. Sharpe , L.A. Harper , J.D. Simmons","doi":"10.1016/S1465-9972(00)00044-1","DOIUrl":"10.1016/S1465-9972(00)00044-1","url":null,"abstract":"<div><p>Gaseous methane (CH<sub>4</sub>) emissions were determined during the winter and summer from `farrow-to-finish' (FF) swine production houses and during the summer from a `farrow-to-wean' (FW) house in 1998 in the coastal plains of North Carolina. The houses were instrumented with sensors to determine cycling of the individual forced-ventilation fans. Laser spectrometry was used to measure CH<sub>4</sub> concentration differences between the intake and exhaust points of the houses. Differences in CH<sub>4</sub> concentrations were combined with fan operation data to calculate CH<sub>4</sub> fluxes from the houses. During the cold winter measurement period, CH<sub>4</sub> fluxes averaged 6.9 g <span><math><mtext>CH</mtext><msub><mi></mi><mn>4</mn></msub><mspace></mspace><mtext>animal</mtext><msup><mi></mi><mn>−1</mn></msup><mtext>d</mtext><msup><mi></mi><mn>−1</mn></msup></math></span> in the FF house. During summer measurement periods, CH<sub>4</sub> fluxes were much greater and averaged 33 and 46 g <span><math><mtext>CH</mtext><msub><mi></mi><mn>4</mn></msub><mspace></mspace><mtext>animal</mtext><msup><mi></mi><mn>−1</mn></msup><mtext>d</mtext><msup><mi></mi><mn>−1</mn></msup></math></span> from the FF and FW houses, respectively. The much larger emissions during the summer than winter, indicate that CH<sub>4</sub> house emissions were primarily from fresh feces and the underground storage/wash pits containing lagoon effluent; and not directly from the animals since temperature would have little affect on direct animal emission. Emission factors based on animal units (au) of 454 kg animal<sup>−1</sup> were much greater at the FW farm with a pull-plug waste management system (7–8 day wash cycle) than at the FF farm with a periodic flush system (8 h wash cycle).</p></div>","PeriodicalId":100235,"journal":{"name":"Chemosphere - Global Change Science","volume":"3 1","pages":"Pages 1-6"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1465-9972(00)00044-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74119399","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 : 2001-01-01DOI: 10.1016/S1465-9972(00)00041-6
N. Bazhin
{"title":"Gas transport in a residual layer of a water basin","authors":"N. Bazhin","doi":"10.1016/S1465-9972(00)00041-6","DOIUrl":"https://doi.org/10.1016/S1465-9972(00)00041-6","url":null,"abstract":"","PeriodicalId":100235,"journal":{"name":"Chemosphere - Global Change Science","volume":"59 1","pages":"33-40"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88208917","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 : 2001-01-01DOI: 10.1016/S1465-9972(00)00028-3
Thomas C. Moore , Lee J. Sullivan , Paul A. Roelle, Viney P. Aneja
Measurements of the mixing ratios of tropospheric NO and NOY (defined as nitric oxide (NO) + nitrogen dioxide (NO2) + peroxyacetyl nitrate (PAN) + nitric acid (HNO3) + particulate nitrate (NO3−) + ⋯) were made over a semi-urban area of central North Carolina at the surface (10 m) and on a tower at heights of 250 m (820 ft) and 433 m (1420 ft) above ground level (AGL) from December 1994 to February 1995. These measurements were compared with synoptic weather data and regional and local upper air soundings in an effort to characterize NO and NOY in the planetary boundary layer in terms of their vertical distributions, diurnal profile, and related transport mechanisms. A pronounced decreasing vertical gradient in both NO and NOY mixing ratios was observed, with a distinct diurnal cycle and nocturnal minimum. Furthermore, the results suggest that NO and NOY were mixed upward from the surface during passage of synoptic meteorological features (and their associated vertical motions). Most importantly, the data reveals that mixing ratios of NO and NOY at the elevated heights did not exist in sufficient concentrations above the inversion layer in the nocturnal boundary layer to be mixed downward upon breakup of the nocturnal inversion and affect surface measurements. Instead, concentrations of NO and NOY were apparently mixed upward during the morning and midday hours by vertical boundary layer processes. Thus, the association of observed increases in surface NO and NOY mixing ratios based solely on downward mixing processes is not justified in all cases, and other sources and processes for these increases must be considered, particularly over rural areas.
{"title":"Vertical distribution of oxides of nitrogen in the semi-urban planetary boundary layer: mixing ratios, sources and transport","authors":"Thomas C. Moore , Lee J. Sullivan , Paul A. Roelle, Viney P. Aneja","doi":"10.1016/S1465-9972(00)00028-3","DOIUrl":"https://doi.org/10.1016/S1465-9972(00)00028-3","url":null,"abstract":"<div><p>Measurements of the mixing ratios of tropospheric NO and NO<em><sub>Y</sub></em> (defined as nitric oxide (NO)<!--> <!-->+<!--> <!-->nitrogen dioxide (NO<sub>2</sub>)<!--> <!-->+<!--> <!-->peroxyacetyl nitrate (PAN)<!--> <!-->+<!--> <!-->nitric acid (HNO<sub>3</sub>)<!--> <!-->+<!--> <!-->particulate nitrate (NO<sub>3</sub><sup>−</sup>)<!--> <!-->+<!--> <!-->⋯) were made over a semi-urban area of central North Carolina at the surface (10 m) and on a tower at heights of 250 m (820 ft) and 433 m (1420 ft) above ground level (AGL) from December 1994 to February 1995. These measurements were compared with synoptic weather data and regional and local upper air soundings in an effort to characterize NO and NO<em><sub>Y</sub></em> in the planetary boundary layer in terms of their vertical distributions, diurnal profile, and related transport mechanisms. A pronounced decreasing vertical gradient in both NO and NO<em><sub>Y</sub></em> mixing ratios was observed, with a distinct diurnal cycle and nocturnal minimum. Furthermore, the results suggest that NO and NO<em><sub>Y</sub></em> were mixed upward from the surface during passage of synoptic meteorological features (and their associated vertical motions). Most importantly, the data reveals that mixing ratios of NO and NO<em><sub>Y</sub></em> at the elevated heights did not exist in sufficient concentrations above the inversion layer in the nocturnal boundary layer to be mixed downward upon breakup of the nocturnal inversion and affect surface measurements. Instead, concentrations of NO and NO<em><sub>Y</sub></em> were apparently mixed upward during the morning and midday hours by vertical boundary layer processes. Thus, the association of observed increases in surface NO and NO<em><sub>Y</sub></em> mixing ratios based solely on downward mixing processes is not justified in all cases, and other sources and processes for these increases must be considered, particularly over rural areas.</p></div>","PeriodicalId":100235,"journal":{"name":"Chemosphere - Global Change Science","volume":"3 1","pages":"Pages 7-23"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1465-9972(00)00028-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91760505","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 : 2001-01-01DOI: 10.1016/S1465-9972(01)00020-4
R. MacKay, M. Ko
{"title":"An analysis of simulated and observed global mean near-surface air temperature anomalies from 1979 to 1999: trends and attribution of causes","authors":"R. MacKay, M. Ko","doi":"10.1016/S1465-9972(01)00020-4","DOIUrl":"https://doi.org/10.1016/S1465-9972(01)00020-4","url":null,"abstract":"","PeriodicalId":100235,"journal":{"name":"Chemosphere - Global Change Science","volume":"4 1","pages":"393-411"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84654150","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 : 2001-01-01DOI: 10.1016/S1465-9972(00)00023-4
Jonathan M Adams , John V.H Constable , Alex B Guenther , Patrick Zimmerman
The flux of volatile organic chemicals from natural vegetation influences various atmospheric properties including oxidation state of the troposphere via the hydroxyl radical (OH), photochemical haze production and the concentration of greenhouse gases (CH4, H2O, CO). Because the Volatile Organic Compound (VOC) flux in the present-day world varies markedly with both vegetation cover and with climate, changes in the emission of VOCs may have damped or amplified past climate changes.
Here we conduct a preliminary study on possible changes in VOC emission resulting from broad scale vegetation and climate change since the Last Glacial Maximum (LGM). During the general period of the LGM (∼25–17,000 years before present {BP}), global forest cover was considerably less than in the present potential situation. The change in vegetation would have resulted in a ∼30% reduction in VOC emission at 643 Tg y−1 relative to the present potential vegetation (912.9 Tg y−1). Uncertainty in global vegetation cover during the LGM bounds the VOC estimate by ±15%. In contrast, during the warmer early-to-mid Holocene (8000 and 5000 BP), with greater forest extent and less desert than during the late Holocene (0 BP), emission rates of VOCs seem likely to have been higher than at present.
Further modifications in VOC emission may have been mediated by a reduction in mean tropical lowland temperatures (by around 5–6°C) decreasing the LGM VOC emission estimate by 38% relative to the warmer LGM scenario.
Increased VOC emissions due to forest expansion and increased tropical temperatures since the LGM may have served as a significant driver of climate change over the last 15 ka y through the influence of VOC oxidation; this can impact tropospheric radiative balance through reductions in the concentration of OH, increasing the concentration of CH4.
The error limits on past VOC emission estimates are large, given the uncertainties of present-day VOC emission rates, paleoecosystem distribution, tropical paleoclimatic conditions, and physiological assumptions regarding controls over VOC emission. Nevertheless, the potential significance of changes in natural VOC emission over the last 20 ka and their influence on climate are an important unknown that should at least be borne in mind as a limit on the understanding of past atmospheric conditions. Elucidation of the role of VOCs in climate change through paleoclimatic general circulation model simulations may improve understanding of past and future changes in climate.
{"title":"An estimate of natural volatile organic compound emissions from vegetation since the last glacial maximum","authors":"Jonathan M Adams , John V.H Constable , Alex B Guenther , Patrick Zimmerman","doi":"10.1016/S1465-9972(00)00023-4","DOIUrl":"https://doi.org/10.1016/S1465-9972(00)00023-4","url":null,"abstract":"<div><p>The flux of volatile organic chemicals from natural vegetation influences various atmospheric properties including oxidation state of the troposphere via the hydroxyl radical (OH), photochemical haze production and the concentration of greenhouse gases (CH<sub>4</sub>, H<sub>2</sub>O, CO). Because the Volatile Organic Compound (VOC) flux in the present-day world varies markedly with both vegetation cover and with climate, changes in the emission of VOCs may have damped or amplified past climate changes.</p><p>Here we conduct a preliminary study on possible changes in VOC emission resulting from broad scale vegetation and climate change since the Last Glacial Maximum (LGM). During the general period of the LGM (∼25–17,000 years before present {BP}), global forest cover was considerably less than in the present potential situation. The change in vegetation would have resulted in a ∼30% reduction in VOC emission at 643 Tg y<sup>−1</sup> relative to the present potential vegetation (912.9 Tg y<sup>−1</sup>). Uncertainty in global vegetation cover during the LGM bounds the VOC estimate by ±15%. In contrast, during the warmer early-to-mid Holocene (8000 and 5000 BP), with greater forest extent and less desert than during the late Holocene (0 BP), emission rates of VOCs seem likely to have been higher than at present.</p><p>Further modifications in VOC emission may have been mediated by a reduction in mean tropical lowland temperatures (by around 5–6°C) decreasing the LGM VOC emission estimate by 38% relative to the warmer LGM scenario.</p><p>Increased VOC emissions due to forest expansion and increased tropical temperatures since the LGM may have served as a significant driver of climate change over the last 15 ka y through the influence of VOC oxidation; this can impact tropospheric radiative balance through reductions in the concentration of OH, increasing the concentration of CH<sub>4</sub>.</p><p>The error limits on past VOC emission estimates are large, given the uncertainties of present-day VOC emission rates, paleoecosystem distribution, tropical paleoclimatic conditions, and physiological assumptions regarding controls over VOC emission. Nevertheless, the potential significance of changes in natural VOC emission over the last 20 ka and their influence on climate are an important unknown that should at least be borne in mind as a limit on the understanding of past atmospheric conditions. Elucidation of the role of VOCs in climate change through paleoclimatic general circulation model simulations may improve understanding of past and future changes in climate.</p></div>","PeriodicalId":100235,"journal":{"name":"Chemosphere - Global Change Science","volume":"3 1","pages":"Pages 73-91"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1465-9972(00)00023-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91760500","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 : 2001-01-01DOI: 10.1016/S1465-9972(00)00038-6
Badar M. Ghauri , M. Ishaq Mirza , Robert Richter , Vincent A. Dutkiewicz , Ali Rusheed , Adil R. Khan , Liaquat Husain
Major ion and trace metal concentrations were determined in aerosols and cloud water at a site in the Himalayan Mountains of Northern Pakistan. In spite of the fact that the site is well removed from significant urban/industrial pollution sources the SO2−4 concentrations in some of the samples were as high as those observed in North America. Concentrations of Se, Tl, Pb, Cl, Cd, Sb, Zn, and As in aerosols were highly enriched relative to average crustal abundances indicating significant anthropogenic contributions. Cloud water concentrations of major ions and trace elements are reported for 18 samples from six different clouds. The pH varied between 5.3 and 6.8 in spite of the fact that the SO2−4 concentration approached 300 μmol in some samples, values often observed in the northeastern US. Selenium was used as a tracer to determine in-cloud production of SO2−4 in these clouds and in three of the six clouds 40–60% of the observed SO2−4 came from in-cloud production.
{"title":"Composition of aerosols and cloud water at a remote mountain site (2.8 kms) in Pakistan","authors":"Badar M. Ghauri , M. Ishaq Mirza , Robert Richter , Vincent A. Dutkiewicz , Ali Rusheed , Adil R. Khan , Liaquat Husain","doi":"10.1016/S1465-9972(00)00038-6","DOIUrl":"https://doi.org/10.1016/S1465-9972(00)00038-6","url":null,"abstract":"<div><p>Major ion and trace metal concentrations were determined in aerosols and cloud water at a site in the Himalayan Mountains of Northern Pakistan. In spite of the fact that the site is well removed from significant urban/industrial pollution sources the SO<sup>2−</sup><sub>4</sub> concentrations in some of the samples were as high as those observed in North America. Concentrations of Se, Tl, Pb, Cl, Cd, Sb, Zn, and As in aerosols were highly enriched relative to average crustal abundances indicating significant anthropogenic contributions. Cloud water concentrations of major ions and trace elements are reported for 18 samples from six different clouds. The pH varied between 5.3 and 6.8 in spite of the fact that the SO<sup>2−</sup><sub>4</sub> concentration approached 300 μmol in some samples, values often observed in the northeastern US. Selenium was used as a tracer to determine in-cloud production of SO<sup>2−</sup><sub>4</sub> in these clouds and in three of the six clouds 40–60% of the observed SO<sup>2−</sup><sub>4</sub> came from in-cloud production.</p></div>","PeriodicalId":100235,"journal":{"name":"Chemosphere - Global Change Science","volume":"3 1","pages":"Pages 51-63"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1465-9972(00)00038-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91760497","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 : 2001-01-01DOI: 10.1016/S1465-9972(00)00032-5
Shang-Shyng Yang, Hsiu-Lan Chang
The effect of green manure amendment, flooding treatment and crop season on methane emission from paddy fields in Taiwan was investigated from August 1994 to July 1996. Sesbania amendment stimulated methane emission and the effect was more significant at the early growth stage of rice. Methane emission was higher in continuous flooding treatment than that in intermittent irrigation. Both redox potential and methane emission showed significant differences between these two irrigation systems. Methane concentration increased sharply with the depth of soil in the intermittent irrigation system due to oxidation; whereas it increased moderately in the continuous flooding treatment. The seasonal methane flux in the first crop season with chemical fertilizer was between 2.73 and 5.23 g m−2; while the value was between 10.54 and 10.56 g m−2 in the second crop season. In the case of Sesbania amendment in the second crop season, the seasonal methane flux in the first crop season was 6.35 g m−2; while the value was between 14.43 and 30.12 g m−2 in the second crop season. Total methane emission in the second crop season was about two to five-fold higher than that in the first crop season.
1994年8月至1996年7月,在台湾调查了绿肥改良、水浸处理和作物季节对稻田甲烷排放的影响。田菁改剂促进了甲烷的排放,且在水稻生长早期效果更为显著。连续淹水处理的甲烷排放量高于间歇灌溉处理。两种灌溉方式的氧化还原电位和甲烷排放均存在显著差异。间断式灌溉系统由于氧化作用,甲烷浓度随土壤深度的增加而急剧增加;而连续驱油处理则有适度增加。第一季施用化肥的甲烷季节通量在2.73 ~ 5.23 g m−2之间;第二季为10.54 ~ 10.56 g m−2。以第二季田菁修正为例,第一季甲烷季通量为6.35 g m−2;第二季为14.43 ~ 30.12 g m−2。第二季的甲烷总排放量约为第一季的2至5倍。
{"title":"Effect of green manure amendment and flooding on methane emission from paddy fields","authors":"Shang-Shyng Yang, Hsiu-Lan Chang","doi":"10.1016/S1465-9972(00)00032-5","DOIUrl":"https://doi.org/10.1016/S1465-9972(00)00032-5","url":null,"abstract":"<div><p><span><span>The effect of green manure amendment, flooding treatment and crop season on methane emission from </span>paddy fields in Taiwan was investigated from August 1994 to July 1996. </span><span><em>Sesbania</em></span><span> amendment stimulated methane emission and the effect was more significant at the early growth stage of rice. Methane emission was higher in continuous flooding treatment than that in intermittent irrigation. Both redox potential<span> and methane emission showed significant differences between these two irrigation systems<span>. Methane concentration increased sharply with the depth of soil in the intermittent irrigation system due to oxidation; whereas it increased moderately in the continuous flooding treatment. The seasonal methane flux in the first crop season with chemical fertilizer was between 2.73 and 5.23 g m</span></span></span><sup>−2</sup>; while the value was between 10.54 and 10.56 g m<sup>−2</sup> in the second crop season. In the case of <em>Sesbania</em> amendment in the second crop season, the seasonal methane flux in the first crop season was 6.35 g m<sup>−2</sup>; while the value was between 14.43 and 30.12 g m<sup>−2</sup> in the second crop season. Total methane emission in the second crop season was about two to five-fold higher than that in the first crop season.</p></div>","PeriodicalId":100235,"journal":{"name":"Chemosphere - Global Change Science","volume":"3 1","pages":"Pages 41-49"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1465-9972(00)00032-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91760498","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 : 2001-01-01DOI: 10.1016/S1465-9972(00)00041-6
N.M. Bazhin
The transport of gases forming in the sedimentary (active) layer of water basins and coming from the atmosphere is discussed. Diffusion equations are used to derive differential equations describing a change in the concentrations in the sedimentary layer with depth. The asymptotic equations describing a change in gas concentration with active layer depth have been derived. It is shown that the rate of gas generation (W) and the position of the upper boundary of bubbling (h) are related via the relationship W∼h−2. A comparison has been made with experimental data.
{"title":"Gas transport in a residual layer of a water basin","authors":"N.M. Bazhin","doi":"10.1016/S1465-9972(00)00041-6","DOIUrl":"https://doi.org/10.1016/S1465-9972(00)00041-6","url":null,"abstract":"<div><p>The transport of gases forming in the sedimentary (active) layer of water basins and coming from the atmosphere is discussed. Diffusion equations are used to derive differential equations describing a change in the concentrations in the sedimentary layer with depth. The asymptotic equations describing a change in gas concentration with active layer depth have been derived. It is shown that the rate of gas generation (<em>W</em>) and the position of the upper boundary of bubbling (<em>h</em>) are related via the relationship <em>W</em>∼<em>h</em><sup>−2</sup>. A comparison has been made with experimental data.</p></div>","PeriodicalId":100235,"journal":{"name":"Chemosphere - Global Change Science","volume":"3 1","pages":"Pages 33-40"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1465-9972(00)00041-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91760499","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 : 2001-01-01DOI: 10.1016/S1465-9972(00)00022-2
Yue-Si Wang, Li Zhou, Ming-Xing Wang, Xun-Hua Zheng
The concentration of atmospheric methane in Beijing is still increasing, although its annual trend has significantly decreased from 2.0% yr−1 in 1985–1989 to 0.5% yr−1 in 1990–1997. The seasonal variability of methane concentration apparently appeared in a double-peak pattern with one peak in winter and the other in summer. It is known that the seasonal inter-annual variations of atmospheric methane in Beijing are different from year to year. From 1986 to 1997, the concentrations of atmospheric methane increased by 184 ppbv, in which about 37% was due to its increase in winter and 21% in summer. After 1993, the trends of methane concentration in summer, which are mainly due to emission from biogenic sources, are negative, while their trends in winter, which are mainly due to emission from non-biogenic sources, are positive with a value of about 25 ppbv yr−1. As a result, the seasonal inter-annual trends from 1993 to 1997 were mainly due to the increase of methane emission from non-biogenic sources in winter. It implies, therefore, that in Beijing the biogenic sources have been decreasing but the non-biogenic ones, such as fossil fuel combustion, have increased.
{"title":"Trends of atmospheric methane in Beijing","authors":"Yue-Si Wang, Li Zhou, Ming-Xing Wang, Xun-Hua Zheng","doi":"10.1016/S1465-9972(00)00022-2","DOIUrl":"10.1016/S1465-9972(00)00022-2","url":null,"abstract":"<div><p>The concentration of atmospheric methane in Beijing is still increasing, although its annual trend has significantly decreased from 2.0% yr<sup>−1</sup> in 1985–1989 to 0.5% yr<sup>−1</sup> in 1990–1997. The seasonal variability of methane concentration apparently appeared in a double-peak pattern with one peak in winter and the other in summer. It is known that the seasonal inter-annual variations of atmospheric methane in Beijing are different from year to year. From 1986 to 1997, the concentrations of atmospheric methane increased by 184 ppbv, in which about 37% was due to its increase in winter and 21% in summer. After 1993, the trends of methane concentration in summer, which are mainly due to emission from biogenic sources, are negative, while their trends in winter, which are mainly due to emission from non-biogenic sources, are positive with a value of about 25 ppbv yr<sup>−1</sup><span>. As a result, the seasonal inter-annual trends from 1993 to 1997 were mainly due to the increase of methane emission from non-biogenic sources in winter. It implies, therefore, that in Beijing the biogenic sources have been decreasing but the non-biogenic ones, such as fossil fuel combustion, have increased.</span></p></div>","PeriodicalId":100235,"journal":{"name":"Chemosphere - Global Change Science","volume":"3 1","pages":"Pages 65-71"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1465-9972(00)00022-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76866965","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}