高寒地区日光温室地温变化及预报   总被引：2，自引：0，他引：2  

朱宝文  胡德奎  郭晓宁  何永晴 《干旱气象》2014,(5):765-772

利用2012年4月至2013年3月青海大通县日光温室内外地温、气温资料和大通县气象站人工观测资料,分析了高寒冷凉地区不同天气类型下日光温室地温变化规律。结果表明;研究区日光温室内日地温呈正弦曲线变化,晴天变化幅度最明显,阴天最小,地温变幅为地表〉5 cm〉10 cm〉15cm〉20 cm;室内地表、10 cm和20 cm平均地温月变化呈波形变化,最大值出现在7月,最小值在12月;随着深度增加,平均地温年较差逐渐减小;晴天、多云天、阴天不同深度地温平均日较差分别为9.6、8.3、6.1℃;地温日垂直变化仅在14时随着深度增加逐渐下降;除晴天室内最高温度外,其余温度要素与地温之间存在极显著正相关关系;建立的日光温室内10 cm最低温度预报方程和地表最低温度预报模型,可以在业务服务中应用。  相似文献   

中国贝类养殖对海洋碳循环的贡献评估     

李海晏  陈涛  张海燕  叶瑛  姚志通  夏枚生 《海洋科学》2014,(4)

造成全球暖化的主要原因是温室气体的过量排放,其中CO2的贡献率达60 %,贝类养殖具有碳沉积作用。依据农业部渔业局编制的《中国渔业统计年签》,以2001年到2010年的年平均产量计算贝类捕获和养殖的碳沉积能力,并评估其碳沉积潜力;计算牡蛎、蛤、扇贝与贻贝四种贝壳单位面积的碳沉积能力并与森林、珊瑚礁的碳沉积能力进行比较分析。本文对我国浅海贝类养殖所具有的碳沉积能力进行评估,以了解贝类养殖对海洋碳循环的贡献,可为争取国家碳份额的合法权益提供基础数据。分析表明我国近十年贝类总产量稳定在1100万吨以上,并有增加的趋势,其中海水养殖贝类约占87.34 %。贝类养殖和捕获总产量的碳沉积和海水养殖产量的碳沉积量分别为58.57、51.15万吨/年,碳沉积能力分别相当于122.28、106.78万公顷的造林,可分别减少大气CO2增加量的0.0125 %、0.0109 %。牡蛎、蛤、扇贝与贻贝的单位面积碳沉积速率分别为1.573、0.388、0.301、1.039吨碳/(公顷?年);牡蛎和贻贝高于森林的碳沉积能力0.479吨碳/(公顷?年);但低于珊瑚礁的碳沉积能力1.8吨碳/(公顷?年)。我国贝类淡、海水养殖产量可分别创造约268.4万元/年、12,711.2万元/年的碳权商机。  相似文献   

Contrasting geochemical signatures on land from the Middle and Late Permian extinction events     

Nathan D. Sheldon  Ramananda Chakrabarti  Gregory J. Retallack  Roger M. H. Smith 《Sedimentology》2014,61(6):1812-1829

The end of the Palaeozoic is marked by two mass‐extinction events during the Middle Permian (Capitanian) and the Late Permian (Changhsingian). Given similarities between the two events in geochemical signatures, such as large magnitude negative δ¹³C anomalies, sedimentological signatures such as claystone breccias, and the approximate contemporaneous emplacement of large igneous provinces, many authors have sought a common causal mechanism. Here, a new high‐resolution continental record of the Capitanian event from Portal Mountain, Antarctica, is compared with previously published Changhsingian records of geochemical signatures of weathering intensity and palaeoclimatic change. Geochemical means of discriminating sedimentary provenance (Ti/Al, U/Th and La/Ce ratios) all indicate a common provenance for the Portal Mountain sediments and associated palaeosols, so changes spanning the Capitanian extinction represent changes in weathering intensity rather than sediment source. Proxies for weathering intensity chemical index of alteration, ?W and rare earth element accumulation all decline across the Capitanian extinction event at Portal Mountain, which is in contrast to the increased weathering recorded globally at the Late Permian extinction. Furthermore, palaeoclimatic proxies are consistent with unchanging or cooler climatic conditions throughout the Capitanian event, which contrasts with Changhsingian records that all indicate a significant syn‐extinction and post‐extinction series of greenhouse warming events. Although both the Capitanian and Changhsingian event records indicate significant redox shifts, palaeosol geochemistry of the Changhsingian event indicates more reducing conditions, whereas the new Capitanian record of reduced trace metal abundances (Cr, Cu, Ni and Ce) indicates more oxidizing conditions. Taken together, the differences in weathering intensity, redox and the lack of evidence for significant climatic change in the new record suggest that the Capitanian mass extinction was not triggered by dyke injection of coal‐beds, as in the Changhsingian extinction, and may instead have been triggered directly by the Emeishan large igneous province or by the interaction of Emeishan basalts with platform carbonates.  相似文献   

The impact of shale gas on the costs of climate policy     

Jan Kersting  Vicki Duscha  Joachim Schleich  Kimon Keramidas 《Climate Policy》2018,18(4):442-458

The use of shale gas is commonly considered as a low-cost option for meeting ambitious climate policy targets. This article explores global and country-specific effects of increasing global shale gas exploitation on the energy markets, on greenhouse gas emissions, and on mitigation costs. The global techno-economic partial equilibrium model POLES (Prospective Outlook on Long-term Energy Systems) is employed to compare policies which limit global warming to 2°C and baseline scenarios when the availability of shale gas is either high or low. According to the simulation results, a high availability of shale gas has rather small effects on the costs of meeting climate targets in the medium and long term. In the long term, a higher availability of shale gas increases baseline emissions of greenhouse gases for most countries and for the world, and leads to higher compliance costs for most, but not all, countries. Allowing for global trading of emission certificates does not alter these general results. In sum, these findings cast doubt on shale gas’s potential as a low-cost option for meeting ambitious global climate targets.

POLICY RELEVANCE

Many countries with a large shale gas resource base consider the expansion of local shale gas extraction as an option to reduce their GHG emissions. The findings in this article imply that a higher availability of shale gas in these countries might actually increase emissions and mitigation costs for these countries and also for the world. An increase in shale gas extraction may spur a switch from coal to gas electricity generation, thus lowering emissions. At the global level and for many countries, though, this effect is more than offset by a crowding out of renewable and nuclear energy carriers, and by lower energy prices, leading to higher emissions and higher mitigation costs in turn. These findings would warrant a re-evaluation of the climate strategy in most countries relying on the exploitation of shale gas to meet their climate targets.  相似文献   

温室气体强迫与东亚亚热带季风演变耦合效应及动力机制研究     

侯立春  林振山  何亮 《地理科学》2018,38(1):151-160

基于主要温室气体（CO₂、CH₄和N₂O）强迫因子和石笋δ¹⁸О观测资料（1~2002 年）,分别利用关联性耦合模型和非线性统计-动力学方法,分析温室气体强迫与东亚亚热带季风演变耦合度的时序规律和定量反演模拟温室气体强迫对近2 000 a东亚亚热带季风演变影响的非线性趋势和相对贡献。研究发现：① 温室气体与季风演变耦合度的高低对应季风的强弱变化,即两者耦合作用越强,东亚亚热带季风越强;反之,两者耦合强度越小,东亚亚热带季风越弱;耦合度峰谷值对应季风极强降水和极端干旱时段。② 时序演变规律为：N₂O和CO₂相互作用与季风演变间耦合效应最强,成为东亚亚热带季风演变的主要驱动力。其次,N₂O一次项和CO₂非线性项对季风演变起主要的负反馈调节机制。③ 时序演变阶段上有所不同：1~180年,CH₄因子对季风演变主要起负反馈调节机制;180~1760年和1760~2002年,对季风演变起主要的驱动和调节机制分别为CO₂因子和N₂O因子;但1900年后N₂O和CO₂相互作用与季风演变的耦合驱动效应近百年来明显增强,耦合度在中等-较强（或极强）之间来回波动转换,耦合作用明显增强,在耦合度由较强（或极强）转弱至中等时,东亚亚热带季风也随之减弱。  相似文献   

日光温室的纹理特征分层提取     

李洪伟  刘勇 《测绘科学》2017,42(8)

针对高分辨率影像上日光温室的信息提取问题,该文提出了利用支持向量机、最近邻算法结合纹理特征在不同层上分别提取连片日光温室和独栋日光温室的方法。实验表明:纹理特征能提高分类精度,在大尺度的层上,分类精度提升幅度较大,但在小尺度的层上,分类精度提升幅度会比较小;并不是参与运算特征数越多,分类精度越高,多数情况下光谱+纹理组合的分类精度最高;提取连片日光温室的最优方案是支持向量机和光谱+形状+纹理(7像素×7像素),总精度为92.86%,Kappa系数为0.90,而提取独栋日光温室最优方案为SVM和光谱+纹理(11像素×11像素),总精度为88.39%,Kappa系数为0.86。  相似文献   

Emission of methane and nitrous oxides from agricultural soils and related global warming potentials of Murshidabad District,West Bengal          下载免费PDF全文

Soham Biswas  Namita Chakma  Swati Mollah 《Singapore journal of tropical geography》2017,38(3):313-331

Agricultural activities emit substantial amounts of methane (CH4) and nitrous oxides (N2O), the two important greenhouse gases (GHG) with high global warming potentials (GWP). So far, many studies have already been carried out at national and state level, but lack micro‐level (district or block‐level) inventory in India. The present study sheds light on the flux of CH4 and N2O (from all possible sources) from agricultural soil of various blocks in the Murshidabad district, based on the inventory prepared, using the IPCC methodology, with adjusted emission factors and coefficients appropriate for the local level. The economy of the Murshidabad district almost completely rests on agriculture as more than 80 per cent of the population is directly or indirectly dependent on it for their livelihood. Paddy is the dominating crop, cultivated on more than 60 per cent of the gross cropped area. The present work is based on the review of various literature and reports collected from respective state government offices and websites. Results show that CH4 and N2O emission from the agricultural fields are 126.405 Gg and 0.652 Gg respectively for the year 2011?12 with a large scale spatial variation (block‐level) within the district.  相似文献   

Tower-Based Greenhouse Gas Measurement Network Design——The National Institute of Standards and Technology North East Corridor Testbed     

Israel LOPEZ-COTO  Subhomoy GHOSH  Kuldeep PRASAD  James WHETSTONE 《大气科学进展》2017,34(9):1095-1105

The North–East Corridor(NEC) Testbed project is the 3rd of three NIST(National Institute of Standards and Technology) greenhouse gas emissions testbeds designed to advance greenhouse gas measurements capabilities. A design approach for a dense observing network combined with atmospheric inversion methodologies is described. The Advanced Research Weather Research and Forecasting Model with the Stochastic Time-Inverted Lagrangian Transport model were used to derive the sensitivity of hypothetical observations to surface greenhouse gas emissions(footprints). Unlike other network design algorithms, an iterative selection algorithm, based on a k-means clustering method, was applied to minimize the similarities between the temporal response of each site and maximize sensitivity to the urban emissions contribution. Once a network was selected, a synthetic inversion Bayesian Kalman filter was used to evaluate observing system performance. We present the performances of various measurement network configurations consisting of differing numbers of towers and tower locations. Results show that an overly spatially compact network has decreased spatial coverage, as the spatial information added per site is then suboptimal as to cover the largest possible area, whilst networks dispersed too broadly lose capabilities of constraining flux uncertainties. In addition, we explore the possibility of using a very high density network of lower cost and performance sensors characterized by larger uncertainties and temporal drift. Analysis convergence is faster with a large number of observing locations, reducing the response time of the filter. Larger uncertainties in the observations implies lower values of uncertainty reduction. On the other hand, the drift is a bias in nature, which is added to the observations and,therefore, biasing the retrieved fluxes.  相似文献   

煤层气开采对环境的影响   总被引：3，自引：0，他引：3  

严群  ;王庆伟  ;李金海 《中国煤炭地质》2008,(12):57-59

煤层气是一种廉价、洁净、高效的新型能源,其开发利用可以弥补常规天然气和燃油的不足,750m^3煤层气可顶替1t标准煤。煤层气开发对环境的影响主要是减少了煤矿甲烷气体的排放,降低温室效应。其负面影响是在钻探、压裂、回注水和提纯过程中会造成煤层和煤层气中杂质气体和有毒有害物质富集,对大气和地下水造成污染。  相似文献   

准噶尔盆地西北缘走滑断层特征及油气地质意义   总被引：4，自引：0，他引：4  

徐怀民  徐朝晖  李震华  刘得光  陈永军  刘巍 《高校地质学报》2008,14(2)

准噶尔盆地西北缘前陆冲断带构造样式复杂多样,除规模较大的逆断层外,还发育一系列北西向的走滑断层。以高分辨率三维地震资料为基础,对断裂体系分析表明克拉玛依—百口泉地区的走滑断层可分为花状走滑断层和简单走滑断层两类,二者在成因、剖面特征等方面具有明显差别。研究结果认为走滑断层对油气的运聚成藏具有重要的双重控制作用,即能作为有效的运移通道,又能够起遮挡作用而形成圈闭。  相似文献