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1.
水库作为温室气体的重要来源,对区域气候变化有不可忽略的影响。然而,目前对水库溶存温室气体的空间异质性及垂向特征的认知仍然欠缺。为了揭示水库分层期和混合期溶存温室气体空间特征及排放通量,也为厘清水库温室气体产生和排放的关键过程提供重要支撑。研究选择东北地区大型水库——汤河水库为对象,于2021年7—9月和10月(分别代表水库分层期和混合期)对水库不同位置(坝前、库中和库尾)开展溶存温室气体垂向分层监测。研究结果显示,水库CH4排放通量变化范围为0.018～0.174 mmol/(m2·d),是大气CH4的源,空间分布为库尾>库中>坝前;CO2通量为-4.91～58.77 mmol/(m2·d),除分层期东支库尾,其余点位均表现为大气CO2的源,空间分布为坝前>库中>库尾。时间上,分层期CH4排放通量(0.071±0.044 mmol/(m2·d))高于混合期((0.027±0.008) mm... 相似文献
2.
自成库以来,三峡水库CO2、CH4等温室气体通量较蓄水前发生明显改变。如何科学认识和客观评估三峡水库修建及运行对其CO2、CH4等温室气体通量的影响备受关注。本文简要回顾了自2009年以来在三峡水库开展CO2、CH4等温室气体通量监测与分析工作,综述认为,现阶段三峡水库温室气体排放以水-气界面扩散释放为主要途径。陆源输入的有机碳是主导三峡水库CO2、CH4产生的主要碳源,但在局部区段或时段自源性有机碳的贡献亦十分显著。同蓄水前相比,三峡水库碳排放量呈现为净增加,淹没效应约占水库C净增量的20%,库区内点面源污染负荷并未对CO2排放的净增量产生显著贡献,阻隔效应和生态系统重建效应对三峡水库碳排放的净增量产生显著贡献。近10年来,监测方法比对、监测点位优化等工作在一定程度上完善了三峡水库温室气体通量监测体系。新方法、新技术的引入也为三峡水库温室气体通量监测分析提供了有利支撑和保障,但复杂水文环境... 相似文献
3.
江西省水库温室气体释放及其影响因素分析 总被引：1，自引：1，他引：0
对江西省柘林、白云山、陡水、洪门、仙女湖5个水库表面N_2O、CH_4和CO_2这3种温室气体的溶存浓度进行测定,估算出这3种温室气体在水-气界面的释放速率分别为0.29~1.05、3.65~39.42和-51.56~1383.21μg/(m~2·h).与其他环境因素的相关性分析表明,总氮浓度是控制N2O释放速率的决定性因素;CH_4的释放速率与水体温度、透明度以及总磷浓度的相关性显著;而CO_2的释放速率与叶绿素a、总有机碳浓度等环境因素均未发现单一的相关性.根据温室气体的全球变暖潜能值计算得到5个水库温室气体总的CO_2等效释放速率(TFeq-CO_2)范围为237.83~2267.83μg CO_2-e/(m~2·h).N2O、CH_4和CO_2的CO_2等效释放速率在TFeq-CO_2中所占比例范围分别为13.94%~83.26%、20.54%~175.21%和-140.43%~60.99%.N_2O和CH_4的CO_2等效释放速率对TFeq-CO_2的贡献基本相当;在柘林和仙女湖水库中CO_2的贡献为负值,而在其余3个水库中CO_2是水库所释放的最为主要的温室气体.本实验中5个水库温室气体的TFeq-CO_2相当于10.52~377.10 t C/a的碳排放,占产生相同电能燃煤发电站年碳排放量的0.05%~1.12%. 相似文献
4.
传统的水-气界面温室气体通量的监测方法具有诸多局限,对其影响因素的分析也大多基于数学统计层面。对此,本研究提供了一种较为新颖的研究和分析方法——基于机器学习的数据预测和分析。本研究采用2种经典机器学习算法——随机森林(RF)和支持向量机(SVM)和2种深度学习算法——卷积神经网络(CNN)和长短时记忆神经网络(LSTM),通过环境因素预测水库水-气界面CO2和CH4扩散通量。此外,采用RF中的特征重要性评估和经典算法决策树(DT),对环境因素和水库温室气体扩散通量的关系进行了全新角度的数据挖掘和分析。结果表明:深度学习算法的预测效果均较好,经典机器学习算法中RF预测效果显著优于SVM。LSTM和RF分别产生了最优的CO2扩散通量和CH4扩散通量的预测精度,均方根误差(RMSE)分别为0.424 mmol/(m2·h)和0.140μmol/(m2·h),预测值与实测值的R2分别为0.960和0.758。RF的特征重要性评估表明沉积物因子... 相似文献
5.
目前准确量化温室气体排放量已成为气候变化研究和政策制定的关键.在IPCC水库温室气体净通量的概念性框架下,国际水电协会汇总分析了全球223座水库的CO2和CH4研究成果,构建了G-res Tool,其可以用于评估已建或待建水库在长时间尺度下的温室气体净通量.本文介绍了G-res Tool模型的基本原理与模型框架,利用模型内置数据库中所涉及的中国长江上游12座典型水库数据进行初步应用分析,12座水库温室气体净通量平均值为88.17 g CO2e/（m2·a）,在全球约7000座水库中所处水平为11.67%,处于低阈值范围.在水库温室气体净通量分析结果中,其他非相关人类活动产生的水库温室气体通量（UAS）在蓄水后总通量（Post）中所占比重远高于蓄水前温室气体通量（Pre）.长江上游水库蓄水后的CH4和CO2通量对于温室效应的贡献量相当.通过将G-res Tool模型蓄水后的温室气体通量评估结果和所涉及到的12座水库中已发表的数据对比分析发现,G-res Tool具有简便、适用面广等特点.但G-res Tool毕竟仍为经验性模型,其基本原理和模块设计上的内在缺陷在很大程度上限制了其应用范围并造成了一定的不确定性.对个案水库而言,长期跟踪观测与机理研究仍是未来减少水库温室气体净通量不确定性的关键. 相似文献
6.
为揭示岩溶湿地表层水体二氧化碳分压(pCO2)的时空分布规律及其扩散通量,以我国最大的岩溶湿地贵州威宁草海为研究对象,分别于2019年7月(丰水期)和12月(枯水期)通过网格布点法,系统采集草海表层湿地水体,测定水样理化指标和离子组成,利用PHREEQCI软件计算水体pCO2,并基于Cole提出的气体扩散模型估算水-气界面二氧化碳(CO2)的扩散通量.结果表明:草海湿地表层水体丰水期pCO2的变化范围为0.44~645.65μatm,平均值为(55.94±124.73)μatm;枯水期变化范围为35.48~707.95μatm,平均值为(310.46±173.54)μatm;丰水期水体整体pCO2低于枯水期,空间上两期水体均呈现东部区域及河流入湖口处pCO2较高,而中西部区域pCO2欠饱和的特征.水-气界面CO2的扩散通量在丰水期变化范围为-43.27~27.16 mmol/(m2·d),平均值(-34.49±12.93)mmol/(m2·d),枯水期变化范围为-33.36~28.15 mmol/(m2·d),平均值(-8.02±15.85)mmol/(m2·d),与其他岩溶湖库相比,水生植物丰富的草海在两个极端水文期CO2扩散通量相对较低,总体表现为大气CO2的汇. 相似文献
7.
对首都圈地区跨18条活动断裂的35条剖面进行了土壤气浓度和通量测量, 结果显示: 各测量剖面土壤气Rn, Hg和CO2的浓度平均值分别为3.2—45.0 kBq/m3, 3.9—24.9 ng/m3和0.154%—2.175%; 其通量平均值分别为3.8—152.1 mBq/(m2·s), 0.1-42.6 ng/(m2·h)和8.5—89.4 g/(m2·d)． 研究区土壤气Rn, Hg和CO2的浓度和通量均呈东高西低的变化趋势, 与首都圈地区由西至东应力水平增高、 地壳厚度逐渐减薄、 沉积层厚度增大、 地震活动逐渐增强等趋势相对应, 这表明首都圈地区土壤气的区域地球化学特征主要受控于上地壳物质结构、 深部气体补给和地震活动, 同时也受到自然环境及土壤类型的影响． 相似文献
8.
2008年汶川地震导致了大量地下含碳气体释放. 本文基于卫星高光谱数据采用差值法获取了汶川地震前后川西地区含碳气体异常的时空分布特征. 结果显示汶川地震前后不同含碳气体异常的时空分布特征不同. 空间分布上,CH4,CO2和CO异常分布于震中附近且受断裂控制明显,与热红外异常特征类似;CO和CO2异常的范围较CH4大,CO除沿断裂带分布外,在四川盆地也大面积出现. 异常出现时间上,CO2异常最早,其次为CH4和CO. 气体来源上,CO2和CH4主要来源于地球内部沿断裂带释放,在地球内部还原条件下,CH4还可由CO2还原形成;CO异常除了沿断裂带释放和由断裂带释放的CH4氧化生成外,还由四川盆地渗漏的CH4氧化生成. 本文结果可用于地震监测预测研究,不仅提供了新的地震前兆观测参数,还为地震热红外异常机制“地球放气温室效应”提供了科学依据,同时对地震引起的地质碳排放研究也有重要意义. 相似文献
9.
地下流体监测数据和地表断层调查都显示构造活动强烈期和大地震前后活动断裂带会伴有大量气体逸出。 中国即将发射的高分五号(GF-5)卫星搭载的大气环境红外甚高光谱分辨率探测仪及全谱段光谱成像仪两个传感器, 主要以大气气体的探测为应用目标。 本文基于两个传感器的参数设置, 使用大气辐射传输模型, 对断层逸出气体中的水汽、 CH4和CO2三种气体在大气中的含量变化对卫星传感器的辐射影响进行了仿真模拟, 分析了两个传感器对水汽、 CH4和CO2气体异常的探测能力。 结果表明, GF-5卫星两个红外传感器特定的光谱通道对大气水汽、 CH4和CO2气体异常变化均有不同程度的敏感性, 可以期待发展具有较高精度的相关气体遥感反演模型, 用于地震的监测及预测。 相似文献
10.
CO2浓度升高对稻田生态系统碳(C)氮(N)循环具有重要作用,阐明CO2浓度升高对稻田CH4和N2O排放的影响是农业生产应对全球气候变化的重要组成部分.文章采用Meta分析的方法,讨论了不同CO2浓度升高状况和田间管理措施条件下CO2浓度升高对稻田CH4和N2O排放的影响,结果可为未来气候条件下稻田温室气体减排提供参考.结果表明:整体平均而言,CO2浓度升高显著增加稻田CH4排放(增幅为23%,P<0.05),同时显著降低稻田N2O排放(降幅为22%,P<0.05).CO2浓度升高对稻田CH4和N2O排放的影响程度与CO2熏气年限和CO2浓度梯度有关.CO2熏气年限≥10a时,CO2浓度升高同时显著降低稻田CH4和N2O排放,降幅分别为27%和53%(P<0.05);随CO2浓度梯度上升,CO2浓度升高对稻田CH4排放的促进作用呈现先减弱后增强的趋势,而对稻田N2O排放的影响则由促进作用变为抑制作用.不同N肥施用量、秸秆还田、水分管理和水稻品种等田间管理措施不同程度地影响稻田CH4和N2O排放对CO2浓度升高的响应.无秸秆和半量秸秆还田时,CO2浓度升高显著促进稻田CH4排放(增幅分别为27%和49%,P<0.05),而全量秸秆还田时,CO2浓度升高对稻田CH4排放无显著影响(P>0.05);随秸秆还田量的增加,CO2浓度升高对稻田N2O排放的抑制作用不断增强.对比持续淹水,间歇灌溉条件下CO2浓度升高减弱了对稻田CH4排放的促进作用,却增强了对稻田N2O排放的抑制作用.未来CO2浓度升高条件下,建议推广全量秸秆还田和间歇灌溉相结合的稻田管理措施,并辅以优化N肥管理和选育"高产低排"水稻品种等方法,达到最优的"增产减排"效果.此外,有必要进行多尺度、多要素和多方法的综合研究,以期有效降低稻田CH4和N2O排放对CO2浓度升高响应的不确定性. 相似文献
11.
福建沿海、台湾海峡GPS观测分析及地球动力学特征研究 总被引：1，自引：1，他引：1
利用 3期GPS联测结果所获得的福建沿海地壳水平运动信息 ,采用ITRF94全球框架为基础的GPS测站地壳运动模型及其处理软件 ,对所获得的观测数据进行处理和精度分析。得到福建省高精度的GPS测站大地坐标、边长及其位移矢量 ,其精度达到 1 7×10 - 8。计算了福建地壳运动速率、主应变率 ,东西与南北向线应变率、面应变率、剪应变率、大地转动率和最大剪应变率等值线并给出了它们的分布图象。根据多年形变和现今GPS观测资料 ,分析福建地壳垂直运动与水平运动 ,显示区域应力场优势分布特征。最后 ,对福建沿海及台湾海峡地壳动力学特征作了初步的探讨 相似文献
12.
Zhivanovich I. Solov’ev A. A. Efremov V. I. Miller N. O. 《Geomagnetism and Aeronomy》2020,60(7):865-871
Geomagnetism and Aeronomy - Two main features define a sunspot as an object: a strong magnetic field and a low umbra temperature. The same can be said about a facular knot, in the center of which... 相似文献
13.
本文搜集了2001—2013年间在太行山与燕山构造带交汇部位先后布设的4个宽频带流动地震台阵和首都圈固定地震台网共192个台站记录到的全球5.5级以上远震事件波形资料,综合采用接收函数H-κ和CCP叠加分析获得了134个基岩台站下方的地壳厚度和泊松比结果.综合分析与前人研究相吻合但更加精细的地壳约束分布信息,发现研究区域的地壳厚度和泊松比在整体上呈现出从西北到东南方向渐变的特征,在南北重力梯度带两侧及其附近呈现出明显的小尺度地壳结构和物质组分的差异,且可明显区分出太行山地区和燕山构造带及盆山交界处的地壳厚度与泊松比的相对差异,这可能反映了这些地区在华北克拉通的构造演化过程中所经历的不同地壳改造过程. 相似文献
14.
针对我国当前较具典型的几种地震社会心理，指出职能部门疏导、防治的工作重点，并从顺应国情、民情及国家经济体制改革的方向出发，提出相应的对策建议。 相似文献
15.
Michele Caputo 《Pure and Applied Geophysics》1964,57(1):66-82
Summary Adopting thePizzetti-Somigliana method and using elliptic integrals we have obtained closed formulas for the space gravity field in which one of the equipotential surfaces is a triaxial ellipsoid. The same formulas are also obtained in first approximation of the equatorial flattening avoiding the use of the elliptic integrals. Using data from satellites and Earth gravity data the gravitational and geometric bulge of the Earth's equator are computed. On the basis of these results and on the basis of recent gravity data taken around the equator between the longitudes 50° to 100° E, 155° to 180° E, and 145° to 180° W, we question the advantage of using a triaxial gravity formula and a triaxial ellipsoid in geodesy. Closed formulas for the space field in which a biaxial ellipsoid is an equipotential surface are also derived in polar coordinates and its parameters are specialized to give the international gravity formula values on the international ellipsoid. The possibility to compute the Earth's dimensions from the present Earth gravity data is the discussed and the value ofMG=(3.98603×1020 cm3 sec–2) (M mass of the Earth,G gravitational constant) is computed. The agreement of this value with others computed from the mean distance Earth-Moon is discussed. The Legendre polinomials series expansion of the gravitational potential is also added. In this series the coefficients of the polinomials are closed formulas in terms of the flattening andMG.Publication Number 327, and Istituto di Geodesia e Geofisica of Università di Trieste. 相似文献
16.
Yu. S. Saenko N. S. Natsvalyan N. Yu. Tepenitsyna 《Pure and Applied Geophysics》1988,127(2-3):335-352
A planetary model of the ionosphere and the protonosphere coupling is described. The system of three-dimensional nonstationary modeling equations of continuity and motion for the ions O+ and H+ is presented. Some numerical results of model calculations are compared with the experimental data. The important role of electromagnetic drifts in the formation of large-scale morphological peculiarities of the ionosphere and the protonosphere coupling is shown. 相似文献
17.
D. Zidarov 《Pure and Applied Geophysics》1973,105(1):655-668
Summary The paleomagnetic field (declination and inclination) in different geological epochs is represented through the field of the so-called magnetic dipole. The optimal dipole coordinates so obtained show that during older geological times the optimal dipole lay outside the earth's centre and moved towards and around the earth centre. It is supposed that the optimal dipole trajectory in the earth coincides with earth core trajectory. This core motion brought about a motion of the masses of the mantle in a direction opposite to the motion of the core. This in turn brought about the break-down of Pangea and the separation of the continents. The drift of the continents, the relative changing of the earth's rotational axis and many other geological and geophysical phenomena may be explained through such a motion, that is through the motion of an eccentrical core towards the earth centre. 相似文献
18.
The nutations of the planets Mars andEarth are investigated and compared. Alarge number of interior structureparameters are involved in the nutationcomputations. The comparison between the observations and the computationsprovides several constraints on these parmeters andtherefore allows a better understanding of the physics of the interior of theplanet. For the Earth, the high precision of the observations of the nutationshas led to a very good determination of interior properties of the planet. ForMars, observations of nutations are not yet available, and we review how theamplitude of the Martian nutations depends on the hypotheses consideredfor its interior. Although Mars is very similar to the Earth, its interior is not well known;for example, we don't knowif its core is liquid or solid. Only if the core is liquid,the Free Core Nutation (FCN) normal mode exists and can alter the nutationswhich are close to the resonance. From the observed geoids, it is known thatboth planets are not in hydrostatic equilibrium. The departure is larger forMars than for the Earth, and consequently, the implication of considering a convective mantle instead of a mantle in hydrostatic equilibrium described byClairaut's equation for the initial equilibrium state of the planet is largeron the Martian nutations than on the Earth nutations. The consequences of theuncertainty in the core dimensions are also examined and shown to be of a veryhigh influence for Mars if the core is liquid, due to the potential changes inthe FCN resonance. The influence of the presence of an inner core, which isknown to exist for the Earth, could be more important for Mars than for theEarth if the inner core is large. Due to the presence of Tharsis on Mars, thetriaxiality of this planet has, additionally, larger effects than on Earth. 相似文献
19.
R. V. Veselovskiy V. E. Pavlov P. Yu. Petrov 《Izvestiya Physics of the Solid Earth》2009,45(7):545-566
The results of paleomagnetic studies of the reference sections of the Riphean and Late Proterozoic intrusive bodies of two remote areas of the Siberian Platform are presented. Within the limits of the Uchur-Maya region the sedimentary rocks of the Gonam, Omakhta, Ennin and Konder formations were studied; and the Riphean sedimentary rocks of the Burdur and Kotuykan formations on the northern and western slopes of the Anabar Uplift and, also, the Late Proterozoic intrusive complexes, located in the basins of the Fomich, Magan, Dzhogdzho and Kotuykan Rivers were studied. The paleomagnetic poles obtained in the course of this work and the present-day geochronological data give grounds to assume that: (1) the accumulation of the Riphean of the Anabar Uplift occurred after the formation of the Uchurskaya series of the Uchur-Maya region and was completed in approximately 1.5 Ga; (2) the Konder layers, compared according to the correlation pattern accepted at the present time [Semikhatov and Serebryakov, 1983] with the bottoms of the Totta formation, can be related to the appreciably more ancient stratigraphic level; (3) the intrusion of the studied intrusive bodies of the northern and western slopes of the Anabar Uplift occurred nonsimultaneously, although within close time intervals of approximately 1.5 Ga. The estimates of the kinematic parameters of the drift of the Siberian Platform within an interval of 1.7–1.0 Ga is carried out. 相似文献
20.
Prof. Dr. W. A. Heiskanen 《Pure and Applied Geophysics》1958,41(1):1-18
Summary The author mentions the aims of the World-wide gravity project he established in the Ohio State University in Columbus, in 1950. He outlines the practical procedure of the gravimetric computations of the undulationsN and the vertical deflection components and and emphasizes that only by the global international cooperation and additional gravity observations at sea carried out during the last decade it has been possible to gather to Columbus the needed gravity material. Since there exist still large gravimetrically unsurveyed areas it is of vital significance to study what gravity anomalies are best to be used for these regions. The given figures concerning the accuracy of theN, and , estimated theoretically and obtained in practice, indicate that in the gravimetrically well surveyed parts of the world like in Europe and the United States we can get gravimetrically on basis of existing gravity material theN-values with accuracy of about 5–10 meters, and and with the accuracy of about 1. The geoid undulationsN are already computed in Columbus for more than 6000 points of the northern hemisphere. The sample maps show the interesting geoid of Europe and vicinity between the latitudes 60° and 30° and longitude 5° W and 30° E, drafted on basis of more than 1000N-values computed at the corners of 1°×1° squares. It is interesting to realize that the geoid undulations in all this area are positive, the extreme values being between 40 and 50 meters. The geophysical significance of the geoid maps of this kind is pointed out. 相似文献