塔里木盆地有机酸来源、分布及对成岩作用的影响   总被引：29，自引：2，他引：29  

蔡春芳  梅博文 《沉积学报》1997,15(3):103-109

塔里木盆地寒武-第三系储层油田水实测表明:有机酸浓度高峰值分布于４３００ｍ以下及不整合面附近；来源于干酪根热成熟作用、原油微生物降解和热化学硫酸盐还原作用等；有机酸浓度多占总碱度３０%～７０%，可达９２%，对油田水的ｐＨ值影响甚大。油田水中Ａｌ浓度在含油层中可高达３.１～５.４ｍｇ/Ｌ，Ａｌ可能以有机络合物形式存在。用国际上常用的水-岩反应地化软件ＳＯＬＭＩＮＥＱ.８８，对石炭、三叠和侏罗系主要造岩矿物溶解-沉淀进行模拟，结果表明，斜长石在储层温度８１℃～１３８℃范围内均可发生溶解作用；低于１３２℃时，高岭石处于超饱和状态，可沉淀；在有机酸参与下，斜长石溶解是该区次生孔隙的主要成因。这与岩观察吻合。  相似文献   

原油的有水热解产生低分子量有机酸的研究   总被引：5，自引：0，他引：5  

陈传平  梅博文 《地球化学》1997,26(1):85-91

用原油及其族组分加入矿物和不同离子浓度的水进行了有水热解，对热解后的水溶液做了低分子量有机酸分析。实验表明，储集层中的原油在热作用下能产生有机酸，但不同条件下，生成的量有所不同。高浓度的卤水对产酸有利，加入不同矿物，砂岩对热解有微弱催化作用，而氧化性矿物能提高产酸量。就原油中不同族组分而言，沥青质生成有机酸的贡献最大。  相似文献   

Enhanced atmospheric phosphorus deposition in Asia and Europe in the past two decades          下载免费PDF全文

Yuepeng Pan  Bowen Liu  Jing Cao  Jin Liu  Shili Tian  Enzai Du 《大气和海洋科学快报》2021,14(5):8-12

磷是植物生长必需的元素,磷缺乏将限制植被生产力及碳汇功能.为厘清全球大气磷沉降的时空格局,本文收集了 1959-2020年发表的396条观测资料.结果发现,全球大气磷沉降的几何均值为0.32 kg ha-1 yr-1,全球大气磷库约4.4Tg yr-1.与1959-2000年相比,近20年亚洲和欧洲大气磷沉降呈现上升趋势,主要来源是农业活动,沙尘传输和燃烧源排放.碳中和背景下,清洁空气行动是否会改变磷沉降的途径和形态,进而影响到生态系统的结构和功能,是需要回答的科学问题.  相似文献   

陆地生态系统固碳速率立体监测方法:进展与挑战          下载免费PDF全文

刘良云  宋博文 《大气科学学报》2022,45(3):321-331

全球CO₂浓度增加造成的全球变暖已成为人类亟需解决的问题,陆地生态系统在过去几十年一直扮演着重要的碳汇角色,吸收了30％左右的人类活动排放CO₂。本文调研分析了陆地生态系统固碳速率空间估算方法,包括样地调查、通量监测、模型模拟、遥感估算等,梳理了各种估算方法的研究现状与进展。样地调查、通量观测等方法可以提供点尺度的固碳速率直接测量信息,但存在观测样本有限、空间代表性不足等问题。模型模拟方法可以从机理的角度描述陆地碳、水、能量循环,模拟预测陆地生态系统固碳速率的状态和变化。然而,在模型建立过程中,抽象和简化会引入结构与假设的不确定性,以及模型驱动数据引入的不确定性等问题是碳循环模型模拟方法面临的重大挑战。卫星遥感具有全球覆盖、分辨率精细、时间序列观测等优点,结合机器学习方法,为地球大数据驱动的全球碳源汇估算提供了新的研究范式。但是,当前各种固碳速率的监测方法还没有满足高度时空异质性的陆地生态系统固碳量监测需求,未来需要整合地面观测、模型模拟和卫星遥感等多种技术手段,提供区域和全球尺度的陆地生态系统碳汇精确估算方法体系和科学数据产品。  相似文献   

Impact of Eddy Characteristics on Turbulent Heat and Momentum Fluxes in the Urban Roughness Sublayer   总被引：1，自引：0，他引：1  

Jun Zou  Bowen Zhou  Jianning Sun 《Boundary-Layer Meteorology》2017,164(1):39-62

Eddy-covariance observations above the densely built-up Centre of Nanjing were made from December 2011 to August 2012. Separate eddy-covariance systems installed at two levels on a 36-m tower located on a rooftop were operated simultaneously, and observations grouped into two sectors (A, B) according to the prevalent wind directions. For sector A, where the nearby buildings are all below the lower measurement level, the sensible heat and momentum fluxes are generally greater at the upper level. For sector B, where several high-rise buildings are located upwind, the sensible heat and momentum fluxes at the upper level are close to those at the lower level. The analysis shows that the turbulent eddy characteristics differ between the two wind sectors, leading to a different behaviour of turbulent exchange between the two levels. A hypothesis is proposed that addresses the vertical variation of turbulent fluxes in the urban roughness sublayer (RSL). For sector A, the buildings block the flow, change the trajectory of scalars, and distort the footprint of scalar fluxes; this ‘blocking effect’ is believed to lead to a smaller sensible heat flux above the canopy layer. Such an effect should decrease with height in the RSL, explaining the increase of the observed turbulent heat flux with height. In addition, the presence of non-uniform building heights adversely affects turbulence organization around the canopy top, and likely elevates the inflection point of the mean flow to a higher elevation close to the upper measurement level, where larger shear results in a larger momentum flux. For sector B, wake effects from the nearby high-rise buildings strongly reduce turbulence organization at higher elevations, leading to similar sensible heat and momentum fluxes at both measurement levels.  相似文献   

Tidal Freshwater Marshes Harbor Phylogenetically Unique Clades of Sulfate Reducers That Are Resistant to Climate-Change-Induced Salinity Intrusion     

Patrick J. Kearns  Nathaniel B. Weston  Jennifer L. Bowen  Tatjana Živković  Melanie A. Vile 《Estuaries and Coasts》2016,39(4):981-991

Rates of sea level rise associated with climate change are predicted to increase in the future, potentially altering ecosystems at all ecological levels. Sea level rise can increase the extent of brackish water intrusion into freshwater ecosystems, which in turn can affect the structure and function of resident microbial communities. In this study, we performed a year-long mesocosm experiment using intact tidal freshwater marsh sediment cores to examine the effect of a 5-part per thousand (ppt) salinity increase on the diversity and community composition of sulfate-reducing prokaryotes. We used a clone library approach to examine the dsrA gene, which encodes an important catalytic enzyme in sulfate reduction. Our results indicate that tidal freshwater marshes contain extremely diverse communities of sulfate-reducing bacteria. Members of these communities were, on average, only 71 % similar to known cultured sulfate reducers and 81 % similar to previously sequenced environmental clones. Salinity and associated increases in sulfate availability did not significantly affect the diversity or community composition of sulfate-reducing prokaryotes. However, carbon quality and quantity, which correlated with depth, were found to be the strongest drivers of sulfate-reducing community structure. Our study demonstrates that the sulfate-reducing community in tidal freshwater marsh sediments appears resistant to increased salinity in the face of sea level rise. Additionally, the microorganisms that comprise this sulfate-reducing community appear to be unique to tidal freshwater marsh sediments and may represent novel lineages of previously undescribed sulfate reducers.  相似文献   

Assimilating surface observations in a four-dimensional variational Doppler radar data assimilation system to improve the analysis and forecast of a squall line case   总被引：1，自引：0，他引：1  

Xingchao Chen  Kun Zhao  Juanzhen Sun  Bowen Zhou  Wen-Chau Lee 《大气科学进展》2016,33(10):1106-1119

This paper examines how assimilating surface observations can improve the analysis and forecast ability of a fourdimensional Variational Doppler Radar Analysis System(VDRAS).Observed surface temperature and winds are assimilated together with radar radial velocity and reflectivity into a convection-permitting model using the VDRAS four-dimensional variational(4DVAR) data assimilation system.A squall-line case observed during a field campaign is selected to investigate the performance of the technique.A single observation experiment shows that assimilating surface observations can influence the analyzed fields in both the horizontal and vertical directions.The surface-based cold pool,divergence and gust front of the squall line are all strengthened through the assimilation of the single surface observation.Three experiments—assimilating radar data only,assimilating radar data with surface data blended in a mesoscale background,and assimilating both radar and surface observations with a 4DVAR cost function—are conducted to examine the impact of the surface data assimilation.Independent surface and wind profiler observations are used for verification.The result shows that the analysis and forecast are improved when surface observations are assimilated in addition to radar observations.It is also shown that the additional surface data can help improve the analysis and forecast at low levels.Surface and low-level features of the squall line—including the surface warm inflow,cold pool,gust front,and low-level wind—are much closer to the observations after assimilating the surface data in VDRAS.  相似文献   

Temperature dependence of the hyperfine parameters of maghemite and al-substituted maghemites     

G. M. da Costa  E. De Grave  L. H. Bowen  P. M. A. de Bakker  R. E. Vandenberghe 《Physics and Chemistry of Minerals》1995,22(3):178-185

Synthetic aluminum-substituted maghemite samples, -(Al _y Fe_1-y )₂O₃ with y=0, 0.032, 0.058, 0.084, 0.106 and 0.151 have been studied by Mössbauer spectroscopy at 8 K and in the range 80 K to 475 K at steps of 25 K. The spectra have been analysed as a superposition of two sextets composed of asymmetrical Lorentzians. The A- and B-site isomer shifts were constrained as: _A=_B-0.12 mm/s. From the temperature dependence of _B it was possible to determine the characteristic Mössbauer temperature and the intrinsic shift. Both quantities clearly increase with increasing Al content, at least up to 10 mole%. The temperature dependence of the A-and B-sites hyperfine fields could be satisfactorily reproduced using the molecular-field theory assuming an antiparallel spin configuration. The exchange integrals were found as: J _AB =-25 K; J _AA =-18 K and J _BB = -3 K. The hyperfine fields show a crossing in the vicinity of 300 K as a result of the relatively strong A-A interaction. The Curie temperature for the non-substituted sample was calculated to be 930 K and decreases to 765 K for the sample with 15 mol% Al. The gradual decrease of the saturation value of the A-site hyperfine field with increasing Al substitution and the constancy of this quantity for the B sites, suggest that the Al cations occupy the B sites.Research Director, National Fund for Scientific Research, Belgium  相似文献   

银川城市地下空间开发的地质安全风险分析     

赵银鑫  宋琨  吉卫波  公亮  虎博文  张晓东  田硕丰 《地球学报》2024,45(1):91-98

城市地下空间受地质环境的影响和制约, 评价地质环境的安全成为地下空间开发的先导问题。结合银川市地下空间资源调查和区划, 选择了地震(活动断裂和场地地震效应)、砂土液化、富水砂卵石层、地基承载力和地表载荷等因素作为评价因子, 在分别确定各要素空间分布的基础上, 进行了单因素的地质风险分析; 采用层次分析和乘积标度相结合的方法, 进行银川市地下空间开发的多因素地质安全风险综合评价。结果表明: 银川市地下空间开发的最主要制约因素是地震和砂土液化; 地质风险的强风险区面积最小, 占总面积的4.10%, 中风险区面积占19.69%, 弱风险区面积最大, 占41.07%, 低风险区占35.13%。这为银川市地下空间开发建设等提供地质参考。  相似文献   

Health co-benefits and the development of climate change mitigation policies in the European Union     

Annabelle Workman  Grant Blashki  Kathryn J. Bowen  David J. Karoly  John Wiseman 《Climate Policy》2019,19(5):585-597

The 2015 Paris Agreement requires increasingly ambitious emissions reduction efforts from its member countries. Accounting for ancillary positive health outcomes (health co-benefits) that result from implementing climate change mitigation policies can provide Parties to the Paris Agreement with a sound rationale for introducing stronger mitigation strategies. Despite this recognition, a knowledge gap exists on the role of health co-benefits in the development of climate change mitigation policies. To address this gap, the case study presented here investigates the role of health co-benefits in the development of European Union (EU) climate change mitigation policies through analysis and consideration of semi-structured interview data, government documents, journal articles and media releases. We find that while health co-benefits are an explicit consideration in the development of EU climate change mitigation policies, their influence on final policy outcomes has been limited. Our analysis suggests that whilst health co-benefits are a key driver of air pollution mitigation policies, climate mitigation policies are primarily driven by other factors, including economic costs and energy implications.

Key policy insights

• Health co-benefits are quantified and monetized as part of the development of EU climate change mitigation policies but their influence on the final policies agreed upon is limited.

• Barriers, such as the immediate economic costs associated with climate action, inhibit the influence of health co-benefits on the development of mitigation policies.

• Health co-benefits primarily drive the development of EU air pollution mitigation policies.

• The separation of responsibility for GHG and non-GHG emissions across Directorate Generals has decoupled climate change and air pollution mitigation policies, with consequences for the integration of health co-benefits in climate policy.

  相似文献