应用涡动相关法计算水热、CO2通量的国内外进展概况

目前涡动相关法被认为是国内外测定CO₂、水热通量的最可靠方法。国外应用此方法解决了均匀下垫面假设下森林和农田等生态系统的CO₂、水热通量的计算问题,目前致力于非理想下垫面(真实地形)的CO₂、水热通量的计算。而国内应用涡动相关技术起步较晚,用此方法测定水热通量已有一定的知识积累,但测定CO₂通量还处于资料收集阶段。我国自然生态系统、环境外交和社会经济可持续发展都要求精确查明我国CO₂的时空变化特征和动力学机制,这应是今后研究的重点,并提出了应用该方法存在的主要问题及可能的解决方法,指出值得深入研究的领域。     

CO2浓度渐增对气温影响的敏感性试验

使用辐射对流模式,研究了中纬度冬季气温对于CO₂浓度变化的敏感性。结果表明:气温变幅随CO₂浓度渐增呈现先快后慢的非线性特征;气温变幅具有一定的稳定性。     

钢铁工业CO2的排放现状及主要的捕集方法

简要讨论了目前CO₂等温室气体的危害、钢铁工业CO₂的排放现状及来源,并针对我国钢铁行业的发展状况,分析了温室气体CO₂的捕集方法.     

[Bmin][BF4]+AMP复合溶液捕集温室气体CO2

采用基于离子液体[Bmin][BF₄]+AMP作为捕集CO₂的复合溶液,在膜吸收-热再生循环装置上,研究了该复合溶液捕集CO₂的过程和传质性能;通过阻力层传质模型,比较了预测值与实验值.结果表明：在相同条件和较高负载下,复合溶液具有较高的传递推动力和更高的传质系数;模型预测值和实验值符合较好,平均误差为12.8%.实验证明复合溶液的传质性能优于单一溶液.     

膜基—气体吸收耦合分离混合气中CO2性能评价

在膜基—气体吸收耦合实验装置上,评价了疏水性PP(聚丙烯)微孔膜,活化MDEA(N-甲基二乙醇胺)溶液分离混合气中CO₂传质性能,研究了气液流速、吸收剂和混合气的浓度等因素对总传质系数的影响,采用阻力层关联方程模型预测总传质系数K_ov值。结果表明:活化MDEA溶液能提高总传质系数K_ov值,模型的计算值和实验值符合较好。     

海洋对人为CO2吸收的三维模式研究

文中用包含海洋化学过程和一个简单生物过程的三维碳循环模式模拟了海洋对大气CO₂的吸收,并分析了碳吸收的纬度分布。模拟工业革命以来海洋对大气CO₂的吸收表明:海洋碳吸收再加上大气CO₂的增加只占由化石燃料燃烧、森林砍伐和土地利用的变化而释放到大气中的CO₂的2/3。1980～1989年期间海洋年平均吸收2.05GtC。海洋人为CO₂的吸收有明显的纬度特征。模式计算的海洋CO₂的吸收在总量与纬度分布上与观测结果比较相符。     

大气CO2浓度升高及气候变化对作物冠层光合影响的数值模拟

利用美国Licor-6200光合作用测定仪,对黄淮海地区代表性冬小麦品种鲁麦23号叶片光合作用速率进行了较为全面的测定,分别确定了冬小麦叶片光—光合作用响应曲线和CO₂—光合作用响应曲线,在此基础上,建立了叶片光合作用模式,并进而建立了一个具有瞬时时间尺度,空间积分为叶片尺度的冬小麦冠层模式,利用模式分别分析了大气中CO₂浓度升高和温度变化对冠层光合作用的不同影响,并在此基础上进一步进行了综合数值分析。单因子分析表明:晴天状况下,冠层光合速率随CO₂浓度升高而上升,当CO₂浓度由330×10^-6上升至660×10^-6时,冠层光合日总量可增加19.7%;冠层光合速率随辐射增加而增大,辐射量增加10.0%,冠层光合日总量可增加6.7%;冠层光合速率随温度升高而下降,温度升高1℃,冠层光合日总量减少2.9%。多因子综合数值分析表明:在辐射量较大的气候背景下,冠层光合日总量对温度和CO₂变化响应更加敏感。本文的实测数据为研究气候变化对中国农业影响提供了最基本的可靠模型参数,冠层光合模型为未来改进作物模型提供了理论基础。     

黑云杉林大气CO2稳定同位素组成δ13C,δ18O的分析

研究CO₂稳定同位素特征可以揭示光合、呼吸作用等众多信息,从而有助于了解生态系统与环境之间的碳循环过程。利用大气CO₂浓度及其稳定同位素的测定资料,分析稳定同位素比δ¹³C、δ¹⁸O,发现两者具有相似的时空分布特征。主要表现在δ¹³C和δ¹⁸O在冠层内具有明显的垂直变化趋势,冠层上部重同位素含量较高,而底部含量较低。从时间变化看,δ¹³C和δ¹⁸O在午后到日落具有较高的水平,而凌晨,δ¹³C和δ¹⁸O较低。运用Keeling图法分析δ¹³C、δ¹⁸O和CO2浓度的关系,发现δ¹³C值主要受光合和呼吸作用影响,与CO₂浓度的高低密切相关;而δ¹⁸O的变化比较复杂,因为δ¹⁸O除受光合、呼吸强度影响外,还取决于环境空气湿度。     

生长旺盛期呼伦贝尔草甸草原生态系统呼吸与CH_4吸收通量的日变化研究

利用静态箱法于2011年结实期和2012年开花期与结实期分别对不同人类活动(自由放牧和刈割)影响下的呼伦贝尔草甸草原及相应的封育草原的CH4通量和植物土壤系统呼吸作用排放的CO2通量进行野外定位观测研究。结果表明:呼伦贝尔草甸草原(放牧和刈割及其对应的封育样地)均表现为CH4的汇,3个观测时期汇强的变化范围为:-23.98±6.40~-95.96±28.57μg Cm-2 h-1。呼伦贝尔草甸草原CH4通量的日变化对温度的响应较为复杂。不同时期呼伦贝尔草甸草原的植物土壤系统呼吸速率的日变化存在差异,水分和温度的共同影响造成2012年结实期日均CO2排放量低于2011年结实期。放牧对呼伦贝尔草甸草原CH4吸收通量的日变化模式的影响较小,但在2011年结实期和2012年开花期促进了CH4日均通量(促进幅度12.05%~93.35%),2012年结实期放牧降低了CH4日均通量(降低幅度23.32%~30.43%);刈割降低CH4吸收日均通量11.55%~60.62%。呼伦贝尔草甸草原日均累计碳排放量中CH4所占比例为0.35%~2.62%,而放牧和刈割行为对呼伦贝尔草甸草原的日均累计碳排放的影响结果在不同物候期以及不同植被群落类型均有不同。     

乌鲁木齐市SO2浓度的分布及其可能原因

根据乌鲁木齐市1994～1997年SO₂浓度和气象监测资料,分析了SO₂浓度的时空分布特征及其可能原因,并对各监测点SO₂ 污染等级作出了评价。     

Uptake and Storage of Anthropogenic CO2 in the Pacific Ocean Estimated Using Two Modeling Approaches

A basin-wide ocean general circulation model(OGCM) of the Pacific Ocean is employed to estimate the uptake and storage of anthropogenic CO 2 using two different simulation approaches.The simulation(named BIO) makes use of a carbon model with biological processes and full thermodynamic equations to calculate surface water partial pressure of CO 2,whereas the other simulation(named PTB) makes use of a perturbation approach to calculate surface water partial pressure of anthropogenic CO 2.The results from the two simulations agree well with the estimates based on observation data in most important aspects of the vertical distribution as well as the total inventory of anthropogenic carbon.The storage of anthropogenic carbon from BIO is closer to the observation-based estimate than that from PTB.The Revelle factor in 1994 obtained in BIO is generally larger than that obtained in PTB in the whole Pacific,except for the subtropical South Pacific.This,to large extent,leads to the difference in the surface anthropogenic CO 2 concentration between the two runs.The relative difference in the annual uptake between the two runs is almost constant during the integration processes after 1850.This is probably not caused by dissolved inorganic carbon(DIC),but rather by a factor independent of time.In both runs,the rate of change in anthropogenic CO 2 fluxes with time is consistent with the rate of change in the growth rate of atmospheric partial pressure of CO 2.     

Effects of an Urban Park and Residential Area on the Atmospheric CO2 Concentration and Flux in Seoul, Korea

The CO₂ concentrations and fluxes over an urban forest site (Namsan) and an urban residential region (Boramae) in Seoul, Korea, during the non-growing season (2–4 March 2011), the growing season (10–12 June 2011), and the late-growing season (22–24 September 2011) were analyzed. The CO₂ concentrations of two sites showed nearly the same diurnal variation, with a maximum value occurring during the night and a minimum value occurring during daytime, as well as the same seasonal variation, with a maximum value during the non-growing season (early spring) and a minimum value during the growing season (summer). The CO₂ flux over the urban forest did not show any typical diurnal variation during the non-growing season, but did show diurnal variation with a small positive value during the night and a large negative value during daytime in the growing and late-growing seasons due to photosynthesis in the urban forest. The CO₂ flux over the urban residential region showed a positive daily mean value for all periods, with large values during the non-growing season and small values during the growing season, and it also showed diurnal variation with two maxima at 0600–1000 LST and 1800–2400 LST, and two minima at 0300-0600 LST and 1100-1500 LST, and was strongly correlated with the use of liquefied natural gas for cooking and heating by surrounding houses.     

Influence of leaf water potential on diurnal changes in CO2 and water vapour fluxes

Mass and energy fluxes between the atmosphere and vegetation are driven by meteorological variables, and controlled by plant water status, which may change more markedly diurnally than soil water. We tested the hypothesis that integration of dynamic changes in leaf water potential may improve the simulation of CO₂ and water fluxes over a wheat canopy. Simulation of leaf water potential was integrated into a comprehensive model (the ChinaAgrosys) of heat, water and CO₂ fluxes and crop growth. Photosynthesis from individual leaves was integrated to the canopy by taking into consideration the attenuation of radiation when penetrating the canopy. Transpiration was calculated with the Shuttleworth-Wallace model in which canopy resistance was taken as a link between energy balance and physiological regulation. A revised version of the Ball-Woodrow-Berry stomatal model was applied to produce a new canopy resistance model, which was validated against measured CO₂ and water vapour fluxes over winter wheat fields in Yucheng (36°57′ N, 116°36′ E, 28 m above sea level) in the North China Plain during 1997, 2001 and 2004. Leaf water potential played an important role in causing stomatal conductance to fall at midday, which caused diurnal changes in photosynthesis and transpiration. Changes in soil water potential were less important. Inclusion of the dynamics of leaf water potential can improve the precision of the simulation of CO₂ and water vapour fluxes, especially in the afternoon under water stress conditions.     

江苏地区二氧化碳浓度时空分布特征分析

利用瓦里关和上甸子大气本底站观测的月平均CO₂浓度数据对GOSAT卫星反演的CO₂浓度数据进行验证,结果表明GOSAT产品与台站观测数据有较好的一致性.利用2009年6月—2011年5月GOSAT反演的CO₂浓度数据,分析了江苏地区CO₂浓度的时空变化特征,结果表明:1)975 hPa高度层CO₂浓度高于850 hPa高度层,CO₂浓度的水平变化要小于垂直变化;2)在季节变化上,CO₂浓度冬季最高,夏季最低,这可能与植被光合作用的强弱变化有关;比较前后两年的CO₂浓度数据,夏季和秋季的增速较快,冬季和春季的增速较慢;3)在日变化上,发现徐州和南京站02时CO₂浓度最高,14时CO₂浓度最低,这可能也与植被光合作用的强弱有关.     

太平洋海气CO2通量对气候事件的响应

应用一个嵌套了海洋生物地球化学循环的太平洋环流碳循环模式,分析了1960～2000年太平洋不同海区海气碳通量随时间的变化。模拟结果显示,赤道太平洋为大气CO₂的排放区,南、北太平洋(南、北纬15°至模式计算区域南、北边界)为吸收区。3个海区海气碳通量随时间均存在显著的波动,其中赤道太平洋海气碳通量年际波动最显著。3个海区海气碳通量年际波动对气候事件的响应并不一致,在El Niño年赤道太平洋冷舌的强度和总溶解无机碳(DIC)的浓度以及输出生产力均会受到上升流减弱的影响而降低,La Niña年这些海气碳通量控制要素的分布情况则正好相反,但在南北太平洋副热带以及高纬度海区,El Niño和La Niña对这些要素带来的影响却并不一定相反,对输出生产力的影响甚至是一致的。以海表温度(SST)为例考察海气碳通量与物理场之间的关系表明,在赤道太平洋上升流对DIC的影响是控制海气碳通量变化的主要因素,而在其他海区,尤其是副热带海区,由于垂直运动的年际变化较小,且生物生产力水平较低,SST的波动对海气碳通量年际变化的影响更加重要。     

厌氧条件下土壤反硝化气体(N2、N2O、NO)和CO2排放——氦环境培养—气体同步直接测定法的应用初探

反硝化过程是维系闭合氮循环所必需的氮素形态转化环节。土壤反硝化过程速率及产物比的直接测定是研究氮循环过程机理的基础,但却是一个难题。为解决此难题,德国卡尔斯鲁厄技术研究所与中国科学院大气物理研究所最近合作新建了一套通过氦环境培养-气体同步直接测定土壤反硝化气体--氮气（N2）、氧化亚氮（N2O）、一氧化氮（NO）和二氧化碳（CO2）排放的系统和与之配套的三阶段培养方法。为检验该新建系统和配套方法测定土壤反硝化过程的准确性和可靠性,以华北地区广泛分布的盐碱地农田土壤（采自山西运城）为研究对象开展实验室培养试验,在初始可溶性有机碳（DOC）供应比较充足约300 mgC kg–1干土（d.s.）的条件下,测试了不同初始土壤硝态氮含量水平（10、100 mgN kg–1d.s.左右,分别表示为10N和100N）的反硝化气体和CO2排放过程。结果显示：100N的反硝化速率（定义为N2、N2O 和NO 排放速率之和）显著高于10N 处理（统计检验显著水平p＜0.01）;两个处理的反硝化产物均以N2为主（质量比分别占77%和75%）,产物的NO/N2O摩尔比分别为1.2和1.5,N2O/N2摩尔比均为0.19;土壤反硝化气体动态排放速率及相关指标的测定结果表明,培养土壤中消失的硝态氮被回收81%～87%,培养前后的氮平衡率达92%～95%。因此,该新建方法测定土壤反硝化速率和产物比的结果具有很好的可靠性,为定量研究土壤反硝化过程提供了有效的直接测定手段。研究中检测到的土壤反硝化产物NO/N2O摩尔比大于1,不同于以往用液体培养基纯培养反硝化细菌得出的NO/N2O摩尔比远小于1的结论。这意味着,不能用NO/N2O摩尔比小于1与否来推断土壤排放的N2O和NO是主要来源于反硝化作用还是硝化作用。