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Estimate of Global Sea-Air CO_2 Flux with Sea-State-Dependent Parameterization 被引量:2
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作者 HU Wei GUAN Changlong 《Journal of Ocean University of China》 SCIE CAS 2008年第3期237-240,共4页
Although the annual global sea-air CO2 flux has been estimated extensively with various wind-dependent-k parameterizations,uncertainty still exists in the estimates. The sea-state-dependent-k parameterization is expec... Although the annual global sea-air CO2 flux has been estimated extensively with various wind-dependent-k parameterizations,uncertainty still exists in the estimates. The sea-state-dependent-k parameterization is expected to improve the uncertainty existing in these estimates. In the present study,the annual global sea-air CO2 flux is estimated with the sea-state-dependent-k parameterization proposed by Woolf(2005) ,using NOAA/NCEP reanalysis wind speed and hindcast wave data from 1998 to 2006,and a new estimate,-2.18 Gt C year-1,is obtained,which is comparable with previous estimates with biochemical methods. It is interesting to note that the averaged value of previous estimates with various wind-dependent-k parameterizations is almost identical to that of previous estimates with biochemical methods by various authors,and that the new estimate is quite consistent with these averaged estimates. 展开更多
关键词 sea-air co2 exchange global co2 flux gas transfer velocity sea-state wave development status
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嘉陵江四川段平水期CH_(4)、CO_(2)排放通量空间分布特征及影响因素 被引量:2
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作者 伍析桥 刘朝荣 +3 位作者 黄兴 罗丹 权秋梅 杨艳 《生态与农村环境学报》 CSCD 北大核心 2024年第1期96-106,共11页
河流是陆地生态系统中内陆水域温室气体的重要排放源。以嘉陵江四川段为研究对象,于2021年10月采集表层水样,运用改良顶空法采集表层水体溶存的CH_(4)、CO_(2),分析了研究区域平水期CH_(4)、CO_(2)溶存浓度与排放通量的空间分布特征,并... 河流是陆地生态系统中内陆水域温室气体的重要排放源。以嘉陵江四川段为研究对象,于2021年10月采集表层水样,运用改良顶空法采集表层水体溶存的CH_(4)、CO_(2),分析了研究区域平水期CH_(4)、CO_(2)溶存浓度与排放通量的空间分布特征,并探究水体理化性质和土地利用类型对温室气体排放的响应。结果表明,嘉陵江四川段人类活动主导了水质变化特征,城市和农业活动是氮素和磷素沿河流方向累积的重要原因。表层水体中CH_(4)和CO_(2)浓度分别为(16.87±15.55)nmol·L^(-1)和(836.11±132.68)μmol·L^(-1),排放通量分别为(68.39±81.26)nmol·m^(-2)·d^(-1)和(1596.08±1291.61)μmol·m^(-2)·d^(-1)。CH_(4)、CO_(2)浓度和排放通量具有较大空间异质性,不同土地利用类型条件下,耕地主导河段接收了较多的非点源污染和陆源碳。这些污染物质的输入导致水体理化性质发生改变,影响水生植物和浮游植物生长以及微生物活动,进而给CH_(4)和CO_(2)产生和释放造成影响。总氮(TN)、磷酸盐(PO_(4)^(3-)-P)和耕地面积占比是影响嘉陵江四川段温室气体排放的关键因子,表明温室气体排放不仅受河流生态环境的影响,还受不同土地利用类型条件下人类活动的影响。 展开更多
关键词 嘉陵江 温室气体 CH_(4) CO_(2) 通量 空间分布
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高效率BaAl_(4)Sb_(2)O_(12)∶Eu^(2+)荧光粉合成与发光性能 被引量:1
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作者 王凯旋 周雪莲 +5 位作者 张钰 王泽 苏日力格 哈拉木吉 田启旭 朝克夫 《发光学报》 EI CAS CSCD 北大核心 2024年第5期753-761,共9页
白光LED作为第四代照明光源已经广泛应用到人们生活的各个领域,其中荧光粉是获得高性能白光LED的关键材料之一。如何用简单的方法制备高性能的荧光粉是目前研究人员的一个挑战性工作。本文采用高温固相法,加入助熔剂H_(3)BO_(3)、NH_(4... 白光LED作为第四代照明光源已经广泛应用到人们生活的各个领域,其中荧光粉是获得高性能白光LED的关键材料之一。如何用简单的方法制备高性能的荧光粉是目前研究人员的一个挑战性工作。本文采用高温固相法,加入助熔剂H_(3)BO_(3)、NH_(4)Cl、SrF_(2)、LiF和BaF_(2),成功制备了BaAl_(4)Sb_(2)O_(12)∶Eu^(2+)(BASO∶Eu^(2+))荧光粉。通过晶体结构分析、发射光谱、X射线光电子能谱(XPS)以及荧光寿命分析,表明过量的Sb_(2)O_(3)能够有效地将Eu^(3+)还原成Eu^(2+),提高Eu^(2+)在563 nm处的荧光强度约12.5倍,内量子效率(IQE)可以达到96.14%。另外,还研究了不同助熔剂对荧光粉晶体结构、荧光强度以及内量子效率的影响。本实验采用的方法简单,避免使用具有一定危险的还原性气体烧结,易于工业化应用以及降低生产成本。 展开更多
关键词 BaAl_(4)Sb_(2)O_(12)∶Eu^(2+) 还原作用 助熔剂 白光LEDs
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Fluxes of CO_2,CH_4 and N_2O from alpine grassland in the Tibetan Plateau 被引量:13
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作者 PEI Zhiyong,OUYANG Hua,ZHOU Caiping,XU Xingliang(Inst. of Geographic Science s and Natural Resources Research, CAS, Beijing 100101, China) 《Journal of Geographical Sciences》 SCIE CSCD 2003年第1期27-34,共8页
Using stat ic chamber technique, fluxes of CO 2 , CH 4 and N 2 O were measured in the alpine grassland area from July 2000 to July 2001, d eterminations of mean fluxes showed that CO 2 and N 2 O were gene rally releas... Using stat ic chamber technique, fluxes of CO 2 , CH 4 and N 2 O were measured in the alpine grassland area from July 2000 to July 2001, d eterminations of mean fluxes showed that CO 2 and N 2 O were gene rally released from the soil, while the alpine grassland accounted for a weak CH 4 sink. Fluxes of CO 2 , CH 4 and N 2 O ranged widely. The highest CO 2 emission occurred in August, whereas a lmost 90% of the whole year emission occurred in the growing season. But the variations of CH 4 and N 2 O fluxes did not show any clear patterns over the one-year-experim ent. During a daily variation, the maximum CO 2 emission occurred at 16:00, and then decreased to the minimum emi ssion in the early morning. Daily pattern analyses indicated that the variation in CO 2 fluxes was positively related to air temperatures (R 2 =0.73) and soil temperatures at a depth of 5 cm (R 2 =0.86), whereas daily variations in CH 4 and N 2 O fluxes were poorly explained by soil temperatures and climatic va riables. CO 2 emissions in this area were much lower than other grasslands in plain areas . 展开更多
关键词 CO 2 CH 4 and N 2 O flux alpine grassland Tibetan Plateau
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Distributions and air-sea fluxes of CO_2 in the summer Bering Sea 被引量:2
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作者 CHEN Liqi GAO Zhongyong +2 位作者 SUN Heng CHEN Baoshan CAI Wei-jun 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2014年第6期1-8,共8页
The 3rd Chinese National Arctic Research Expedition (CHINARE-Arctic III) was carried out from July to September in 2008. The partial pressure of CO2 (pCO2) in the atmosphere and in surface seawater were determined... The 3rd Chinese National Arctic Research Expedition (CHINARE-Arctic III) was carried out from July to September in 2008. The partial pressure of CO2 (pCO2) in the atmosphere and in surface seawater were determined in the Bering Sea during luly 11-27, 2008, and a large number of seawater samples were taken for total alkalinity (TA) and total dissolved inorganic carbon (DIC) analysis. The distributions of CO2 parameters in the Bering Sea and their controlling factors were discussed. The pCO2 values in surface seawater presented a drastic variation from 148 to 563 laatm (1 μatm = 1.013 25× 10-1Pa). The lowest pCOz values were observed near the Bering Sea shelf break while the highest pCO2 existed at the western Bering Strait. The Bering Sea generally acts as a net sink for atmospheric CO2 in summer. The air-sea CO2 fluxes in the Bering Sea shelf, slope, and basin were estimated at -9.4, -16.3, and -5.1 mmol/(m2.d), respectively. The annual uptake of CO2 was about 34 Tg C in the Bering Sea. 展开更多
关键词 partial pressure of co2 co2 system air-sea co2 flux Bering Sea
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Seasonal and Annual Variations of CO_2 Fluxes in Rain-Fed Winter Wheat Agro-Ecosystem of Loess Plateau, China 被引量:8
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作者 WANG Wen LIAO Yun-cheng GUO Qiang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2013年第1期147-158,共12页
To accurately evaluate the carbon sequestration potential and better elucidate the relationship between the carbon cycle and regional climate change, using eddy covariance system, we conducted a long-term measurement ... To accurately evaluate the carbon sequestration potential and better elucidate the relationship between the carbon cycle and regional climate change, using eddy covariance system, we conducted a long-term measurement of CO 2 fluxes in the rain-fed winter wheat field of the Chinese Loess Plateau. The results showed that the annual net ecosystem CO 2 exchange (NEE) was (-71.6±5.7) and (-65.3±5.3) g C m-2 y-1 for 2008-2009 and 2009-2010 crop years, respectively, suggesting that the agro-ecosystem was a carbon sink (117.4-126.2 g C m-2 yr-1). However, after considering the harvested grain, the agro- ecosystem turned into a moderate carbon source. The variations in NEE and ecosystem respiration (R eco ) were sensitive to changes in soil water content (SWC). When SWC ranged form 0.15 to 0.21 m3 m-3, we found a highly significant relationship between NEE and photosynthetically active radiation (PAR), and a highly significant relationship between R eco and soil temperature (T s ). However, the highly significant relationships were not observed when SWC was outside the range of 0.15-0.21 m3 m-3. Further, in spring, the R eco instantly responded to a rapid increase in SWC after effective rainfall events, which could induce 2 to 4-fold increase in daily R eco , whereas the R eco was also inhibited by heavy summer rainfall when soils were saturated. Accumulated R eco in summer fallow period decreased carbon fixed in growing season by 16- 25%, indicating that the period imposed negative impacts on annual carbon sequestration. 展开更多
关键词 CO 2 flux carbon sequestration soil water content rainfall event rain-fed winter wheat agro-ecosystem
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典型农业流域不同类型池塘水体CO_(2)排放特征
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作者 陈嘉宁 肖启涛 +6 位作者 刘臻婧 肖薇 谢晖 罗菊花 邱银国 胡正华 段洪涛 《湖泊科学》 EI CAS CSCD 北大核心 2024年第1期88-98,共11页
内陆水体是大气CO_(2)收支估算的重要组成部分。农业流域分布着大量池塘景观水体,且具备蓄洪抗旱、消纳污染、水产养殖等多种功能。但是,农业流域不同功能的小型池塘CO_(2)排放特征尚不清楚。本研究以极具农业流域代表性的烔炀河流域为... 内陆水体是大气CO_(2)收支估算的重要组成部分。农业流域分布着大量池塘景观水体,且具备蓄洪抗旱、消纳污染、水产养殖等多种功能。但是,农业流域不同功能的小型池塘CO_(2)排放特征尚不清楚。本研究以极具农业流域代表性的烔炀河流域为研究对象,选取流域中用于水产养殖(养殖塘)、生活污水承纳(村塘)、农业灌溉(农塘)、蓄水(水塘)的4个功能不同的景观池塘,基于为期1年的野外实地观测,以明确农业流域小型池塘CO_(2)排放特征。结果表明,不同功能池塘水体CO_(2)排放差异显著,受养殖活动、生活污水输入和农田灌溉等人类活动影响,养殖塘((80.37±100.39)mmol/(m^(2)·d))、村塘((48.69±65.89)mmol/(m^(2)·d))和农塘((13.50±15.81)mmol/(m^(2)·d))是大气CO_(2)的热点排放源,其CO_(2)排放通量分别是自然蓄水塘((4.52±23.26)mmol/(m^(2)·d))的18、11和3倍。统计分析也表明,该流域池塘CO_(2)排放变化总体上受溶解氧、营养盐等因素驱动。4个不同景观池塘CO_(2)排放通量全年均值为(37.31±67.47)mmol/(m^(2)·d),是不容忽视的CO_(2)排放源,其中养殖塘和村塘具有较高的CO_(2)排放潜力,在未来研究中需要重点关注。 展开更多
关键词 农业流域 池塘 CO_(2)通量 影响因子
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Abiotic contribution to total soil CO_2 flux across a broad range of land-cover types in a desert region 被引量:5
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作者 MA Jie LIU Ran LI Yan 《Journal of Arid Land》 SCIE CSCD 2017年第1期13-26,共14页
As an important component of ecosystem carbon(C) budgets, soil carbon dioxide(CO2) flux is determined by a combination of a series of biotic and abiotic processes. Although there is evidence showing that the abiot... As an important component of ecosystem carbon(C) budgets, soil carbon dioxide(CO2) flux is determined by a combination of a series of biotic and abiotic processes. Although there is evidence showing that the abiotic component can be important in total soil CO2 flux(R(total)), its relative importance has never been systematically assessed. In this study, after comparative measurements of CO2 fluxes on sterilized and natural soils, the R(total) was partitioned into biotic flux(R(biotic)) and abiotic flux(R(abiotic)) across a broad range of land-cover types(including eight sampling sites: cotton field, hops field, halophyte garden, alkaline land, reservoir edge, native saline desert, dune crest and interdune lowland) in Gurbantunggut Desert, Xinjiang, China. The relative contribution of R(abiotic) to R(total), as well as the temperature dependency and predominant factors for R(total), R(biotic) and R(abiotic), were analyzed. Results showed that R(abiotic) always contributed to R(total) for all of the eight sampling sites, but the degree or magnitude of contribution varied greatly. Specifically, the ratio of R(abiotic) to R(total) was very low in cotton field and hops field and very high in alkaline land and dune crest. Statistically, the ratio of R(abiotic) to R(total) logarithmically increased with decreasing R(biotic), suggesting that R(abiotic) strongly affected R(total) when R(biotic) was low. This pattern confirms that soil CO2 flux is predominated by biotic processes in most soils, but abiotic processes can also be dominant when biotic processes are weak. On a diurnal basis, R(abiotic) cannot result in net gain or net loss of CO2, but its effect on transient CO2 flux was significant. Temperature dependency of R(total) varied among the eight sampling sites and was determined by the predominant processes(abiotic or biotic) of CO2 flux. Specifically, R(biotic) was driven by soil temperature while R(abiotic) was regulated by the change in soil temperature(ΔT). Namely, declining temperature(ΔT0) resulted in positive R(abiotic)(i.e., CO2 released from soil). Without recognition of R(abiotic), R(biotic) would be overestimated for the daytime and underestimated for the nighttime. Although R(abiotic) may not change the sum or the net value of daily soil CO2 exchange and may not directly constitute a C sink, it can significantly alter the transient apparent soil CO2 flux, either in magnitude or in temperature dependency. Thus, recognizing the fact that abiotic component in R(total) exists widely in soils has widespread consequences for the understanding of C cycling. 展开更多
关键词 soil co2 flux biotic flux abiotic flux temperature dependence Gurbantunggut Desert
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Soil CO_2 flux in relation to dissolved organic carbon,soil temperature and moisture in a subtropical arable soil of China 被引量:2
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作者 LOUYun-sheng LIZhong-pei ZHANGTao-lin 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2003年第5期715-720,共6页
Soil CO 2 emission from an arable soil was measured by closed chamber method to quantify year round soil flux and to develop an equation to predict flux using soil temperature, dissolved organic carbon(DOC) and soil... Soil CO 2 emission from an arable soil was measured by closed chamber method to quantify year round soil flux and to develop an equation to predict flux using soil temperature, dissolved organic carbon(DOC) and soil moisture content. Soil CO 2 flux, soil temperature, DOC and soil moisture content were determined on selected days during the experiment from August 1999 to July 2000, at the Ecological Station of Red Soil, the Chinese Academy of Sciences, in a subtropical region of China. Soil CO 2 fluxes were generally higher in summer and autumn than in winter and spring, and had a seasonal pattern more similar to soil temperature and DOC than soil moisture. The estimation was 2 23 kgCO 2/(m 2·a) for average annual soil CO 2 flux. Regressed separately, the reasons for soil flux variability were 86 6% from soil temperature, 58 8% from DOC, and 26 3% from soil moisture, respectively. Regressed jointly, a multiple equation was developed by the above three variables that explained approximately 85 2% of the flux variance, however by stepwise regression, soil temperature was the dominant affecting soil flux. Based on the exponential equation developed from soil temperature, the predicted annual flux was 2 49 kgCO 2/(m 2·a), and essentially equal to the measured one. It is suggested the exponential relationship between soil flux and soil temperature could be used for accurately predicting soil CO 2 flux from arable soil in subtropical regions of China. 展开更多
关键词 soil CO 2 flux soil temperature DOC soil moisture arable soil
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Monitoring and simulation of water,heat,and CO_2 fluxes in terrestrial ecosystems based on the APEIS-FLUX system 被引量:4
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作者 WATANABEMasataka WANGQinxue +6 位作者 HAYASHISeiji MURAKAMIShogo LIUJiyuan OUYANGZhu LIYan LIYingnian WANGKelin 《Journal of Geographical Sciences》 SCIE CSCD 2005年第2期131-141,共11页
The Integrated Environmental Monitoring (IEM) project, part of the Asia-Pacific Environmental Innovation Strategy (APEIS) project, developed an integrated environmental monitoring system that can be used to detect, mo... The Integrated Environmental Monitoring (IEM) project, part of the Asia-Pacific Environmental Innovation Strategy (APEIS) project, developed an integrated environmental monitoring system that can be used to detect, monitor, and assess environmental disasters, degradation, and their impacts in the Asia-Pacific region. The system primarily employs data from the moderate resolution imaging spectrometer (MODIS) sensor on the Earth Observation System-(EOS-) Terra/Aqua satellite, as well as those from ground observations at five sites in different ecological systems in China. From the preliminary data analysis on both annual and daily variations of water, heat and CO2 fluxes, we can confirm that this system basically has been working well. The results show that both latent flux and CO2 flux are much greater in the crop field than those in the grassland and the saline desert, whereas the sensible heat flux shows the opposite trend. Different data products from MODIS have very different correspondence, e.g. MODIS-derived land surface temperature has a close correlation with measured ones, but LAI and NPP are quite different from ground measurements, which suggests that the algorithms used to process MODIS data need to be revised by using the local dataset. We are now using the APEIS-FLUX data to develop an integrated model, which can simulate the regional water, heat, and carbon fluxes. Finally, we are expected to use this model to develop more precise high-order MODIS products in Asia-Pacific region. 展开更多
关键词 APEIS-flux system Asia-Pacific Environmental Innovation Strategy (APEIS) co2 flux Integrated Environmental Monitoring (IEM) MODIS water vapor flux
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高塔涡度相关观测长三角农业区CO_(2)通量变化特征及影响因素
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作者 包恒鑫 张弥 +7 位作者 谢燕红 贾磊 葛培 邱吉丽 何洋 张圳 肖薇 刘寿东 《生态学报》 CAS CSCD 北大核心 2024年第17期7552-7568,共17页
人类活动对景观尺度农业下垫面的CO_(2)收支有着不可忽视的影响,明确在人类活动影响下景观尺度农业区CO_(2)通量的变化特征及影响因素对增汇减排策略的制定具有重要的意义。使用高塔涡度相关法对长三角地区一处农业区CO_(2)通量开展连... 人类活动对景观尺度农业下垫面的CO_(2)收支有着不可忽视的影响,明确在人类活动影响下景观尺度农业区CO_(2)通量的变化特征及影响因素对增汇减排策略的制定具有重要的意义。使用高塔涡度相关法对长三角地区一处农业区CO_(2)通量开展连续观测以明确其源汇特征及影响因子。结果表明:该农业区CO_(2)通量在春夏秋季表现为白天吸收CO_(2),夜间排放CO_(2)的日变化动态,三个季节CO_(2)通量的变化范围分别为-0.15—0.14、-0.60—0.28、-0.21—0.19 mg m^(-2)s^(-1),冬季则表现为全天排放CO_(2),日变化范围为0—0.14 mg m^(-2)s^(-1)。每年的6—11月CO_(2)吸收明显,其余时间段以排放为主,吸收峰值和排放峰值分别出现在每年的8月和11月,多年均值分别为-0.14、0.08 mg m^(-2)s^(-1)。研究区2019—2021年表现为一个逐年上升的大气碳源,CO_(2)通量年总量均值为(142.73±99.01)gC m^(-2)a^(-1)。在半小时尺度上光量子通量密度(PPFD)、10 cm处土壤温度(Ts)以及饱和水汽压差是影响CO_(2)收支的关键环境要素,日尺度上PPFD、Ts是主要控制因子,月尺度上,Ts是最为重要的影响因素,同时降雨量以及归一化植被指数也影响着CO_(2)通量。经人为CO_(2)开源数据清单得到的通量塔15 km范围内人为CO_(2)排放量为(429.7±30.01)gC m^(-2)a^(-1),抵消了该农业区稻田、森林等自然生态系统的碳汇作用。 展开更多
关键词 农业区 CO_(2)通量 高塔涡度相关法 人类活动
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农业小流域句容水库出入库水体CO_(2)、CH_(4)浓度与通量特征
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作者 史家宾 王圆媛 +6 位作者 曹琰梅 柯浩楠 武熳秋 刘超 肖启涛 胡正华 李琪 《生态与农村环境学报》 CAS CSCD 北大核心 2024年第11期1485-1494,共10页
为探究农业小流域句容水库出入库水体二氧化碳(CO_(2))、甲烷(CH_(4))的变化特征,本研究以句容水库为研究对象,进行为期2年的逐月野外试验,探明农业小流域水库水体CO_(2)、CH_(4)浓度与通量特征。结果表明:句容水库出入库水体CO_(2)、CH... 为探究农业小流域句容水库出入库水体二氧化碳(CO_(2))、甲烷(CH_(4))的变化特征,本研究以句容水库为研究对象,进行为期2年的逐月野外试验,探明农业小流域水库水体CO_(2)、CH_(4)浓度与通量特征。结果表明:句容水库出入库水体CO_(2)、CH_(4)浓度和排放通量存在明显的空间差异。就年均CO_(2)浓度和排放通量而言,入库口A〔(108.57±14.27)μmol·L^(-1)、(210.55±36.58)mmol·m^(-2)·d^(-1)〕和入库口B〔(162.74±17.86)μmol·L^(-1)、(338.74±47.25)mmol·m^(-2)·d^(-1)〕显著高于出库口〔(28.04±3.53)μmol·L^(-1)、(10.05±4.04)mmol·m^(-2)·d^(-1)〕;入库口B年均CH_(4)浓度和排放通量〔(747.05±190.63)nmol·L^(-1)、(1.84±0.46)mmol·m^(-2)·d^(-1)〕显著高于出库口〔(115.75±15.75)nmol·L^(-1)、(0.11±0.02)mmol·m^(-2)·d^(-1)〕。句容水库水体CO_(2)、CH_(4)浓度和排放通量有明显的季节变化,水体CO_(2)、CH_(4)浓度和排放通量均表现为暖季高、冷季低的变化规律,其水体CO_(2)、CH_(4)浓度和排放通量的时间变化显著受到水温、溶解氧浓度和降水量的影响,同时外源氮素的输入影响CO_(2)、CH_(4)浓度和排放通量的空间变化。综上,农业小流域句容水库是大气CO_(2)、CH_(4)的排放源,排放通量高于国内水库平均值。 展开更多
关键词 CO_(2) CH_(4) 排放通量 水库 农业小流域
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CO_2 flux and seasonal variability in the turbidity maximum zone and surrounding area in the Changjiang River estuary 被引量:4
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作者 李学刚 宋金明 +3 位作者 袁华茂 李宁 段丽琴 曲宝晓 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2015年第1期222-232,共11页
The turbidity maximum zone(TMZ) is one of the most important regions in an estuary.However,the high concentration of suspended material makes it difficult to measure the partial pressure of CO_2(pCO_2) in these region... The turbidity maximum zone(TMZ) is one of the most important regions in an estuary.However,the high concentration of suspended material makes it difficult to measure the partial pressure of CO_2(pCO_2) in these regions.Therefore,very little data is available on the pCO_2 levels in TMZs.To relatively accurately evaluate the CO_2 flux in an example estuary,we studied the TMZ and surrounding area in the Changjiang(Yangtze) River estuary.From seasonal cruises during February,August,November 2010,and May 2012,the pCO_2 in the TMZ and surrounding area was calculated from pH and total alkalinity(TA)measured in situ,from which the CO_2 flux was calculated.Overall,the TMZ and surrounding area acted as a source of atmosphere CO_2 in February and November,and as a sink in May and August.The average FCO_2was-9,-16,5,and 5 mmol/(m^2·d) in May,August,November,and February,respectively.The TMZ's role as a source or sink of atmosphere CO_2 was quite different to the outer estuary.In the TMZ and surrounding area,suspended matter,phytoplankton,and pH were the main factors controlling the FCO_2,but here the influence of temperature,salinity,and total alkalinity on the FCO_2 was weak.Organic carbon decomposition in suspended matter was the main reason for the region acting as a CO_2 source in winter,and phytoplankton production was the main reason the region was a CO_2 sink in summer. 展开更多
关键词 co2 flux seasonal variability turbidity maximum zone Changjiang River estuary
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我国东部典型内源和外源性静态水体N_(2)O排放与生态系统呼吸的关系初探
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作者 李春旺 王华 +4 位作者 淦冲 赵学梅 张声权 颜晓元 夏永秋 《农业资源与环境学报》 CAS CSCD 北大核心 2024年第2期401-409,共9页
内陆水体是大气中N_(2)O的重要排放源,受到国内外广泛关注,为了探讨水生生态系统中水体N_(2)O排放通量与生态系统呼吸的响应关系,本研究以我国东部典型外源性和内源性静态水体为研究对象,在2022年4月29日-5月4日对10个表层水体N_(2)O排... 内陆水体是大气中N_(2)O的重要排放源,受到国内外广泛关注,为了探讨水生生态系统中水体N_(2)O排放通量与生态系统呼吸的响应关系,本研究以我国东部典型外源性和内源性静态水体为研究对象,在2022年4月29日-5月4日对10个表层水体N_(2)O排放通量和生态系统呼吸指标进行测定,结合贝叶斯方法初步探讨了水体N_(2)O排放通量和生态系统呼吸之间的关系。结果表明:外源性水体N_(2)O排放通量和生态系统呼吸均显著高于内源性水体(P<0.05),水体N_(2)O排放通量与CO_(2)排放通量和BOD5均呈显著正相关关系(P<0.05)。通过贝叶斯方法构建了水体N_(2)O排放通量与生态系统呼吸(CO_(2)和BOD_(5))之间的数学模型,可解释水体N_(2)O排放通量变异性的61%~71%,并且明确了模拟结果的不确定性。此外,本研究进一步区分了内源性水体与外源性水体N_(2)O排放通量和生态系统呼吸的关系,在内源性水体中,N_(2)O的产生受碳源限制的影响大于氮源限制,而在外源性水体中N_(2)O排放通量与CO_(2)排放通量的耦合关系大于内源性水体。研究表明,生态系统呼吸与水体N_(2)O排放通量间有很强的响应关系,本研究为区域水体N_(2)O排放通量估算方法和生态系统呼吸耦合机制研究提供了基础。 展开更多
关键词 贝叶斯方法 N_(2)O排放通量 生态系统呼吸 内源性水体 外源性水体
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A Multilayer Study of pCO2 in the Surface Waters of the Yellow and South China Seas in Spring and the Sea-Air Carbon Dioxide Flux 被引量:3
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作者 LIU Chunying ZHANG Chuang YANG Xiaoman GONG Haidong ZHANG Zhengbin 《Journal of Ocean University of China》 SCIE CAS 2008年第3期263-268,共6页
A multilayer study of pCO2 for the Yellow and South China Seas in the surface waters was conducted based on data from four cruises sponsored by the China SOLAS Project in 2005 and 2006,including data for the surface m... A multilayer study of pCO2 for the Yellow and South China Seas in the surface waters was conducted based on data from four cruises sponsored by the China SOLAS Project in 2005 and 2006,including data for the surface microlayer(SML) ,subsurface layer(SSL) and surface layer(SL) . The carbon fluxes across the air-sea interface were calculated. The results showed that the pCO2 values in the surface waters of the study area decreased in the following order:pCO2 SML> pCO2 SSL> pCO2 SL. The highest values were found in March for all SML,SSL and SL,followed by those in April,and the lowest were in May. The pCO2 values had a significant positive correlation with temperature or salinity. While there was no relationship between pCO2 and longitude,there was a significant negative correlation between it and latitude,i.e.,'high latitude low pCO2'. By using four calculation models,the carbon dioxide fluxes(FC O2) in spring in the Yellow and South China Seas,which were found to act as a 'sink' of atmospheric CO2,were preliminarily estimated on the basis of the pCO2 data in the SML to be -7.00×106 t C and -22.35×106 t C,respectively. It is suggested that the FC O2calculated on the basis of pCO2 data in the SML is more reliable than that calculated on the basis of those in the SL. 展开更多
关键词 the Yellow Sea South China Sea SPRING Pco2 multilayer study carbon dioxide fluxes Fco2
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水稻生长季CO_(2)通量的时间动态和影响因子研究
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作者 张丽君 胡凝 +4 位作者 刘珊珊 徐敏 王伟 邰久 葛培 《环境科学与技术》 CAS CSCD 北大核心 2024年第3期27-36,共10页
为了明确长三角地区稻麦轮作生态系统中水稻生长季CO_(2)通量的多时间尺度变化特征,量化环境因子对农田CO_(2)通量变化的贡献度,拆分环境因子的直接影响和间接影响,该研究利用涡度相关观测系统进行了2年CO_(2)通量的连续观测,分析了辐... 为了明确长三角地区稻麦轮作生态系统中水稻生长季CO_(2)通量的多时间尺度变化特征,量化环境因子对农田CO_(2)通量变化的贡献度,拆分环境因子的直接影响和间接影响,该研究利用涡度相关观测系统进行了2年CO_(2)通量的连续观测,分析了辐射类、温度类、水汽类和风速对CO_(2)通量的影响。结果表明:稻麦轮作生态系统在水稻生长季是一个二氧化碳汇,2020、2021年水稻生长季的总固碳量分别为396.3、491.9 g/m^(2)(以C计);CO_(2)通量也有明显的日变化,呈现出“U形”和“V型”的单峰曲线,吸收峰值出现在第200~250天。在不同时间尺度上,影响CO_(2)通量的主控因子始终是光合有效辐射;但随时间尺度的增加,各个因子贡献度的差异逐渐减小。饱和水汽压差也是影响CO_(2)通量的重要因子,它与光合有效辐射的交互作用会抑制彼此对CO_(2)通量的直接贡献。 展开更多
关键词 稻麦轮作生态系统 CO_(2)通量 贡献度 交互作用 涡度相关
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土壤CO_(2)排放对微咸水与淡水交替灌溉的响应
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作者 陈艺伟 管瑶 +4 位作者 贺兴宏 李会文 王剑 王育强 范德宝 《节水灌溉》 北大核心 2024年第8期102-109,共8页
为揭示微咸水与淡水交替灌溉模式对土壤CO_(2)排放通量变化规律的影响,研究极端干旱区棉田3种灌溉水质(矿化度分别为2、3、5 g/L)和3种不同配比咸淡水交替[微咸水∶淡水=1∶1(W1);微咸水∶淡水=1∶4(W2);微咸水∶淡水=1∶0(W3)]灌溉对土... 为揭示微咸水与淡水交替灌溉模式对土壤CO_(2)排放通量变化规律的影响,研究极端干旱区棉田3种灌溉水质(矿化度分别为2、3、5 g/L)和3种不同配比咸淡水交替[微咸水∶淡水=1∶1(W1);微咸水∶淡水=1∶4(W2);微咸水∶淡水=1∶0(W3)]灌溉对土壤CO_(2)排放通量的影响。结果表明:①以2 g/L为对照,3 g/L微咸水与淡水交替灌溉处理CO_(2)累积排放通量减少了6.03%~7.19%;5 g/L微咸水与淡水交替灌溉处理CO_(2)累积排放通量减少了9.83%~10.15%;②在相同矿化度条件下,土壤CO_(2)累积排放通量为W2处理>W1处理>W3处理,淡水灌水量多的处理CO_(2)排放通量较大。③以2 g/L为对照,3 g/L和5 g/L处理产量平均提高了1.25%和3.64%,W1处理产量相较于W2、W3处理平均提高了24.02%和14.12%。随着灌溉水矿化度的增大,土壤CO_(2)排放通量减小,所有不同配比下矿化度为5 g/L的处理CO_(2)排放量均小于2、3 g/L的处理;在微咸水与淡水交替灌溉条件下,矿化度为3 g/L且微咸水∶淡水=1∶1的灌水处理,土壤CO_(2)排放通量降低且棉花产量最大,能够为合理利用微咸水及保护干旱区灌区农田生态环境提供理论依据。 展开更多
关键词 咸淡水 交替灌溉 土壤CO_(2)排放通量
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Dissolution of TiO_(2) and TiN inclusions in CaO–SiO_(2)–B_(2)O_(3)-based fluorine-free mold flux
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作者 Dawei Cai Li Zhang +2 位作者 Wanlin Wang Lei Zhang Il Sohn 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第9期1740-1747,共8页
Mold flux serves the crucial metallurgical function of absorbing inclusions, directly impacting the smoothness of the casting process as well as the cast slab quality. In this study, the dissolution behavior and mecha... Mold flux serves the crucial metallurgical function of absorbing inclusions, directly impacting the smoothness of the casting process as well as the cast slab quality. In this study, the dissolution behavior and mechanism of Ti O_(2)and Ti N inclusions in molten Ca O–Si O_(2)–B_(2)O_(3)-based fluorine-free mold flux were explored by in situ single hot thermocouple technology combined with X-ray photoelectron spectroscopy.The results showed that Ti O_(2) inclusions are effectively dissolved by the molten slag within 76 s, during which the original octahedral [Ti O_(6)]^(8-)structures are destroyed and convert to the networker tetrahedral [Ti O_(4)]^(4-)structures. However, the dissolution rate is much lower for Ti N inclusions than for Ti O_(2)inclusions. This can be attributed to the fact that the Ti N particles need to be oxidized and then dissolved in the molten slag to form tetrahedral [Ti O4]4-and octahedral [Ti O_(6)]^(8-)structures during the Ti N inclusion dissolution process, which is accompanied by the generation of a large amount of N_(2)gas. Moreover, Ca Ti O_(3)crystals tend to nucleate and grow on bubble surfaces with sufficient octahedral [Ti O_(6)]^(8-)structures and Ca^(2+)ions, eventually resulting in the molten slag being in a solid–liquid mixed state. 展开更多
关键词 TiO_(2)inclusion TiN inclusion mold flux fluorine-free continuous casting
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MoS_(2)纳米片功能化PAN锂金属电池隔膜的制备及锂枝晶抑制作用
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作者 董帮达 翟云云 +3 位作者 刘海清 黄振鹏 李祖光 李蕾 《高等学校化学学报》 SCIE EI CSCD 北大核心 2024年第1期145-153,共9页
引导锂离子流的均匀分布可以有效抑制锂枝晶的形成-生长,推动锂金属电池的产业化应用.本文采用化学插层法制备出单层或少层、结构完整的MoS_(2)纳米片,将二维MoS_(2)纳米片喷涂到静电纺聚丙烯腈(PAN)纤维膜上,制得MoS_(2)@PAN复合隔膜.M... 引导锂离子流的均匀分布可以有效抑制锂枝晶的形成-生长,推动锂金属电池的产业化应用.本文采用化学插层法制备出单层或少层、结构完整的MoS_(2)纳米片,将二维MoS_(2)纳米片喷涂到静电纺聚丙烯腈(PAN)纤维膜上,制得MoS_(2)@PAN复合隔膜.MoS_(2)涂层的引入不仅提高了离子电导率(1.02 mS/cm)、Li+迁移数(0.59)和电解液亲和性,而且降低了复合隔膜的孔径,使其孔径分布均一.这些特性协同作用,调控了通过MoS_(2)@PAN复合隔膜的Li+流分布,促进了Li+在锂金属表面的均匀沉积,抑制了锂枝晶的形成-生长.因此,MoS_(2)@PAN复合隔膜组装的Li/Li电池在1 mA/cm^(2)电流密度下以14 mV的超低过电位可稳定循环长达500 h,循环后的锂金属表面没有明显的枝晶生长.此外,MoS_(2)@PAN复合隔膜组装的LiFePO_(4)/Li电池在2C倍率下循环550次后保持92%的初始容量,表现出更稳定的循环性能.通过隔膜调节Li+通量实现了锂的均匀沉积,为抑制锂枝晶的形成-生长提供了一种可行的策略. 展开更多
关键词 二维材料 MoS_(2)纳米片 锂金属电池隔膜 调节Li+通量 抑制锂枝晶形成-生长
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Simulation of CO_2 and sensible/latent heat fluxes exchange between land surface and atmosphere over cropland and grassland in semi-arid region,China 被引量:1
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作者 姜纪峰 延晓冬 +2 位作者 黄耀 郭维栋 刘辉志 《Journal of Forestry Research》 SCIE CAS CSCD 2007年第2期114-118,共5页
A comparison between simulated land surface fluxes and observed eddy covariance (EC) measurements was conducted to validate Integrated Biosphere Simulator (IBIS) at Tongyu field observation station (44°25'N... A comparison between simulated land surface fluxes and observed eddy covariance (EC) measurements was conducted to validate Integrated Biosphere Simulator (IBIS) at Tongyu field observation station (44°25'N, 122°52'E) in Jilin Province, China. Results showed that the IBIS model could reproduce net ecosystem CO2 exchange (NEE), sensible and latent heat fluxes reasonably, as indicated by correlation coefficients exceeding the significant level of 0.05. It was also evident that the NEE and sensible heat fluxes were characterized by diurnal and seasonal variation both in the grassland and the cropland ecosystems, while the latent heat fluxes correlated with evapotranspiration, only took on the diurnal variation during the growing season. Moreover, both sensible heat fluxes and the latent heat fluxes were larger in the cropland ecosystem than that in the degraded grassland ecosystem. This different characteristic was possibly correlated with vegetation growing situation in the two kinds of ecosystems. A close agreement between observation and simulation on NEE, sensible heat fluxes and latent heat flux was obtained both in the degraded grassland and the cropland ecosystems. In addition, the annual NEE in the model was overestimated by 23.21% at the grassland and 27.43% at the cropland, sensible heat flux with corresponding 9.90% and 11.98%, respectively, and the annual latent heat flux was underestimated by 4.63% and 3.48%, respectively. 展开更多
关键词 Integrated biosphere simulator (IBIS) co2 flux Sensible flux Latent heat flux Cropland ecosystem Grassland ecosystem
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