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901.
“一带一路”建设研究进展   总被引:25,自引:6,他引:19  
“一带一路”经历了从中国倡议到国际共识的巨大转变,正在成为世界上越来越多国家和政治领袖们探索全球经济治理新模式的平台。伴随这种转变以及“一带一路”建设所取得的成就,“一带一路”研究已经深入到除了基础科学领域外的几乎所有学科。本文根据中国知网(CNKI)数据分析了4年多来“一带一路”研究文献的特征,而后总结了与地理学密切相关的“一带一路”核心议题的研究进展。研究发现:① 自2014年以来“一带一路”研究发文量迅速上升,由2014年的1000多篇飙升到2017年的20000多篇;② 文献比较庞杂,以宏观性、战略性和一般性文献为主,舆论性很高,基于深入研究的高水平学术文献少,还不能很好地支撑“一带一路”建设;③ 对外直接投资、互联互通、“走出去”、全球化、全球治理、命运共同体、人民币国际化等得到的关注较多;④ 地理学在“一带一路”的战略内涵和理论构建、地缘政治经济分析、“中欧班列”、海上航运战略支点、海外投资模式、经贸格局及其经济影响、资源环境问题等方面研究较为深入。最后,本文呼吁加强“一带一路”的理论建构以及建设机制和国别研究,并积极开展中外学者之间“一带一路”研究对话以及合作研究。  相似文献   
902.
本项研究选取适宜于西宁盆地及其周边地区生长的2种优势草本植物垂穗披碱草(Elymus nutans Griseb)和细茎冰草(Agropyron trachycaulum (Linn.) Gaertn.)作为供试种,通过室内种植培育方式,采用浓度梯度分别为50mmol/L、100mmol/L、150mmol/L、200mmol/L的Na2SO4溶液对2种植物进行盐胁迫处理。在盐胁迫试验处理后的第15d、30d和45d时,分别测定2种植物单根抗拉力和单根抗拉强度。试验结果表明:相同盐胁迫浓度时,2种植物单根抗拉力随生长期增长呈逐渐增大,单根抗拉强度随生长期增加表现为逐渐降低的变化规律;相同生长期时,2种植物单根抗拉力随着胁迫液浓度由0mmol/L增加至200mmol/L时表现为逐渐减小趋势,单根抗拉强度则随着胁迫液浓度增加呈逐渐增大的变化规律;进一步研究表明,在相同胁迫浓度和相同生长期条件下,细茎冰草单根抗拉力和单根抗拉强度分别较垂穗披碱草高0.008N~0.025N和9.646MPa~72.807MPa;2种草本植物单根抗拉力与根径之间呈指数函数关系;2种草本单根抗拉强度分别随根径的增加而逐渐减小,且均与根径呈幂函数关系。本该研究成果对于进一步探讨寒旱环境盐胁迫条件下,草本植物根系力学强度特征及其变化规律具有重要理论研究价值,同时对于有效防治研究区水土流失、浅层滑坡等地质灾害的发生具有实际指导意义。  相似文献   
903.
Quantitative analysis of the impact factors in energy-related CO2 emissions serves as an important guide for reducing carbon emissions and building an environmentally-friendly society. This paper aims to use LMDI method and a modified STIRPAT model to research the conventional energy-related CO2 emissions in Kazakhstan after the collapse of the Soviet Union. The results show that the trajectory of CO2 emissions displayed U-shaped curve from 1992 to 2013. Based on the extended Kaya identity and additive LMDI method, we decomposed total CO2 emissions into four influencing factors. Of those, the economic active effect is the most influential factor driving CO2 emissions, which produced 110.86 Mt CO2 emissions, with a contribution rate of 43.92%. The second driving factor is the population effect, which led to 11.87 Mt CO2 emissions with a contribution rate of 4.7%. On the contrary, the energy intensity effect is the most inhibiting factor, which caused–110.90 Mt CO2 emissions with a contribution rate of–43.94%, followed by the energy carbon structure effect resulting in–18.76 Mt CO2 emissions with a contribution rate of–7.43%. In order to provide an in-depth examination of the change response between energy-related CO2 emissions and each impact factor, we construct a modified STIRPAT model based on ridge regression estimation. The results indicate that for every 1% increase in population size, economic activity, energy intensity and energy carbon structure, there is a subsequent increase in CO2 emissions of 3.13%, 0.41%, 0.30% and 0.63%, respectively.  相似文献   
904.
Soil moisture is an important parameter for agriculture, meteorological, and hydrological studies. This paper focuses on soil-moisture estimation methodology based on the multi-angle high-and low-incidence-angle mode RADARSAT-2 data obtained over bare agricultural fields in an arid area. Backscattering of the high-and low-incidence angles is simulated by using AIEM(advanced integral equation model), with the surface-roughness estimation model built based on the simulated data. Combining the surface-roughness estimation model with the backscattering model of the low-incidence-angle mode, a soil-moisture estimation method is put forward. First, the natural logarithm(ln) of soil moisture was obtained and then the soil moisture calculated. Soil moisture of the study area in Dunhuang, Gansu Province, was obtained based on this method; a good agreement was observed between the estimated and measured soil moisture. The coefficient of determination was 0.85, and the estimation precision reached 4.02% in root mean square error(RMSE). The results illustrate the high potential of the approach developed and RADARSAT-2 data to monitor soil moisture.  相似文献   
905.
针对二维切换系统的Fornasini-Marchesini(FM)状态空间模型,对系统耗散稳定性以及耗散镇定控制器的设计问题进行研究.首先,根据系统模型的特点,给出了二维系统(T,S,R)-δ-耗散性的定义,并提出二维切换系统渐近稳定和满足(T,S,R)-δ-耗散性的充分条件;然后利用稳定性条件和投影引理,设计了二维(T,S,R)-δ-耗散状态反馈控制器.最后,通过一个数值实例来验证所设计控制器的有效性.  相似文献   
906.
BCC S2S模式对亚洲夏季风准双周振荡预报评估   总被引:1,自引:1,他引:0       下载免费PDF全文
利用1994-2013年ERA-Interim及NCEP/NCAR再分析数据,对国家气候中心(BCC)次季节到季节尺度模式(S2S)1994-2013年的回报试验数据进行亚洲季风区准双周振荡(QBWO)预报能力评估,并诊断模式预报误差来源。结果表明:BCC S2S模式对QBWO的预报能力随着预报提前时间的增长而降低,9 d后预报技巧明显减弱,其周期、传播特征和强度出现误差;在提前9 d预报中,印度洋地区QBWO对流-环流系统结构松散,信号偏弱,对流向东传播,这与印度洋平均态的预报误差有关,夏季对流平均态低层水汽场在西太平洋和阿拉伯海较强,而东印度洋、孟加拉湾一带偏弱;西北太平洋地区QBWO具有向西北传播的特征,但强度偏弱,可能原因是预报低估了QBWO对流西北侧低层涡度的超前信号,经涡度方程诊断发现,地转涡度平流正贡献微弱,相对涡度平流在对流西北侧引发负涡度,从而减弱了对流西北侧由低层正涡度引发的有利条件。  相似文献   
907.
This paper provides a detailed analysis of the Tokyo Metropolitan Emissions Trading Scheme (Tokyo ETS), Japan’s first emissions trading scheme with mandatory cap initiated by the government of Tokyo. Unlike trading schemes in other countries, the Tokyo ETS covers indirect emissions from the commercial sector. It is well known that a variety of market barriers impede full realization of energy efficiency opportunities, especially in the commercial sector. Experiences with the Tokyo ETS should therefore provide important lessons for the design of climate change mitigation policies, especially when targeting the commercial sector. The emissions from covered entities have been drastically reduced from those at the scheme’s outset, with an average 14% reduction as of the end of the first commitment period of five years (2010–2014) compared with 2009 levels. This paper shows that the Tokyo ETS alone did not cause these reductions; there were other drivers. Among them, the energy savings triggered by the Great East Japan Earthquake in 2011 were crucial. The contribution of credit trading, in contrast, was limited since most of the covered entities reduced emissions by themselves. Through an investigation of official reports, an assessment of the emissions data from the covered entities compared to those of uncovered entities and in-depth interviews with firms covered by the scheme, this paper confirms that the main drivers of emissions reductions by covered entities were separate from the ETS. In fact, the advisory aspect of the scheme seems to be much more important in encouraging energy-saving actions.

Key policy insights

  • Most of the observed emission reductions were not caused by the Tokyo ETS alone.

  • An advisory instrument was crucial to the effectiveness of the Tokyo ETS.

  • The experience of the Tokyo ETS suggests that making full use of the advantages of emissions trading is difficult in the case of the commercial sector.

  • Price signals have not provided a stimulus to climate change mitigation actions, which implies that establishing a cap to yield effective carbon prices poses a challenge.

  相似文献   
908.
This article shows the potential impact on global GHG emissions in 2030, if all countries were to implement sectoral climate policies similar to successful examples already implemented elsewhere. This assessment was represented in the IMAGE and GLOBIOM/G4M models by replicating the impact of successful national policies at the sector level in all world regions. The first step was to select successful policies in nine policy areas. In the second step, the impact on the energy and land-use systems or GHG emissions was identified and translated into model parameters, assuming that it would be possible to translate the impacts of the policies to other countries. As a result, projected annual GHG emission levels would be about 50 GtCO2e by 2030 (2% above 2010 levels), compared to the 60 GtCO2e in the ‘current policies’ scenario. Most reductions are achieved in the electricity sector through expanding renewable energy, followed by the reduction of fluorinated gases, reducing venting and flaring in oil and gas production, and improving industry efficiency. Materializing the calculated mitigation potential might not be as straightforward given different country priorities, policy preferences and circumstances.

Key policy insights

  • Considerable emissions reductions globally would be possible, if a selection of successful policies were replicated and implemented in all countries worldwide.

  • This would significantly reduce, but not close, the emissions gap with a 2°C pathway.

  • From the selection of successful policies evaluated in this study, those implemented in the sector ‘electricity supply’ have the highest impact on global emissions compared to the ‘current policies’ scenario.

  • Replicating the impact of these policies worldwide could lead to emission and energy trends in the renewable electricity, passenger transport, industry (including fluorinated gases) and buildings sector, that are close to those in a 2°C scenario.

  • Using successful policies and translating these to policy impact per sector is a more reality-based alternative to most mitigation pathways, which need to make theoretical assumptions on policy cost-effectiveness.

  相似文献   
909.
To assess the potential impacts of the US withdrawal from the Paris Agreement, this study applied GCAM-TU (an updated version of the Global Change Assessment Model) to simulate global and regional emission pathways of energy-related CO2, which show that US emissions in 2100 would reduce to ?2.4?Gt, ?0.7?Gt and ?0.2?Gt under scenarios of RCP2.6, RCP3.7 and RCP4.5, respectively. Two unfavourable policy scenarios were designed, assuming a temporary delay and a complete stop for US mitigation actions after 2015. Simulations by the Model for the Assessment of Greenhouse-gas Induced Climate Change (MAGICC) indicate that the temperature increase by 2100 would rise by 0.081°C–0.161°C compared to the three original RCPs (Representative Concentration Pathways) if US emissions were kept at their 2015 levels until 2100. The probability of staying below 2°C would decrease by 6–9% even if the US resumes mitigation efforts for achieving its Nationally Determined Contribution (NDC) target after 2025. It is estimated by GCAM-TU that, without US participation, increased reduction efforts are required for the rest of the world, including developing countries, in order to achieve the 2°C goal, resulting in 18% higher global cumulative mitigation costs from 2015 to 2100.

Key policy insights
  • President Trump’s climate policies, including planned withdrawal from the Paris Agreement, cast a shadow on international climate actions, and would lower the likelihood of achieving the 2°C target.

  • To meet the 2°C target without the US means increased reduction efforts and mitigation costs for the rest of the world, and considerable economic burdens for major developing areas.

  • Active state-, city- and enterprise-level powers should be supported to keep the emission reduction gap from further widening even with reduced mitigation efforts from the US federal government.

  相似文献   
910.
利用Python语言实现了每日对CMACast下发的最新风云二号G星(FY-2G)云导风(AMV)和射出长波辐射(OLR)两个定量业务产品的实时自动解码和可视化出图,并与国家卫星气象中心下发的卫星天气应用平台(SWAP)的显示进行了对比。结果表明:两者显示一致。在显示所有AMV文件风矢量数据的前提下,本文可视化产品较目前版本SWAP的显示更为疏密均匀,没有出现重叠现象;Python出图自带的高洛德(Gouraud)明暗处理渲染方式则在对OLR格点产品可视化显示中提供了一种更为平滑,细腻的方法。利用本研究方法对风云二号卫星定量产品进行可视化具备自动化和视觉美观的特点,值得在基层气象部门业务中推广。  相似文献   
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