高速公路用地地籍调查方法和精度研究   总被引：1，自引：0，他引：1  

林辉 《地理空间信息》2008,6(4):118-120

介绍高速公路用地的权属调查和地籍测量方法,根据高速公路用地特点,重点讨论了确定高速公路地籍测量精度指标问题.得出高速公路宗地界址点精度统一采用±0．3m比较适宜的结论。最后介绍了RTK技术在高速公路地籍测量的应用情况。  相似文献   

中国碳总量控制新进展：省域碳配额分配研究综述     

谭显春  程永龙  顾佰和 《气候变化研究进展》2023,19(1):63-73

为加快碳达峰、碳中和进程,中国正探索碳总量控制制度,而省域碳配额分配是落实总量控制目标的重要抓手。从分配准则、分配方法和分配结果3个环节对关于中国省域碳配额分配的研究开展综述。结果表明,兼顾公平和效率原则是各方研究共识,但对于公平原则的解读和测度尚存争议。指标法和优化法在省域碳配额分配中被广泛采用,前者能兼顾多方利益,后者能提升分配效率;混合法因具备多方法优势而具有较大发展潜力;博弈法因缺乏透明度而较为罕见。既有分配结果对各省分配的减排责任与各省实情间尚有差距,并仅关注某一特定年份当期或者某一时间区间内累计的碳配额分配,缺乏对逐年碳配额分配的关注。建议后续研究进一步关注兼顾公平与效率、考虑区域异质性与消费端排放责任、采用多方法组合、兼容个案特殊性的跨期动态分配方法学的构建过程。  相似文献   

中国东部地区典型臭氧污染过程防控敏感性及减排情景研究          下载免费PDF全文

周德荣  刘祎  高健  唐志伟  蔡哲  黄昕  覃栎 《大气科学学报》2023,46(5):667-678

近年来,我国东部地区夏季臭氧污染问题日渐凸显,成为影响空气质量、环境改善的重要因素之一,为量化评估臭氧前体物减排对臭氧污染的影响,本文以2021年6月19—30日中国东部地区臭氧污染过程为例,应用空气质量模型CMAQ-DDM方法与卫星遥感反演算法分析了东部地区臭氧浓度对人为源前体物排放敏感性的响应程度,并对臭氧前体物设置不同削减比例开展减排情景模拟,结果表明:1)2021年6月19—30日中国东部出现了一次长时间区域性臭氧污染过程,大部分城市达轻度至中度污染水平;2)整个污染时段东部地区主要以VOCs(Volatile Organic Compounds,挥发性有机物)控制区或VOCs与NO_x协同控制区为主,模型模拟与卫星反演结果具有较好的一致性,污染过程前段(19—25日)东部地区对VOCs敏感性较高,污染后段(26—30日)大部分地区转为VOCs和NO_x协同控制区,特别是河南、安徽、江苏部分地区,对NO_x敏感性提高较为显著;3)在相同减排比例条件下(VOCs∶NO_x=2∶1),减排幅度越大,臭氧降幅越大,当VOCs削减比例由20％提高到40％时,臭氧浓度降幅由1.7％增大至3.6％;由VOCs和NO_x协同减排(2∶1)过渡为强化NO_x减排(1∶1)的分阶段控制优于单一的减排控制方案,臭氧改善率平均增强0.1％;仅削减高架源NO_x对臭氧降幅不显著。  相似文献   

Ranking the risk of CO2 emissions from seagrass soil carbon stocks under global change threats     

《Global Environmental Change》2023

Seagrass meadows are natural carbon storage hotspots at risk from global change threats, and their loss can result in the remineralization of soil carbon stocks and CO₂ emissions fueling climate change. Here we used expert elicitation and empirical evidence to assess the risk of CO₂ emissions from seagrass soils caused by multiple human-induced, biological and climate change threats. Judgments from 41 experts were synthesized into a seagrass CO₂ emission risk score based on vulnerability factors (i.e., spatial scale, frequency, magnitude, resistance and recovery) to seagrass soil organic carbon stocks. Experts perceived that climate change threats (e.g., gradual ocean warming and increased storminess) have the highest risk for CO₂ emissions at global spatial scales, while direct threats (i.e., dredging and building of a marina or jetty) have the largest CO₂ emission risks at local spatial scales. A review of existing peer-reviewed literature showed a scarcity of studies assessing CO₂ emissions following seagrass disturbance, but the limited empirical evidence partly confirmed the opinion of experts. The literature review indicated that direct and long-term disturbances have the greatest negative impact on soil carbon stocks per unit area, highlighting that immediate management actions after disturbances to recover the seagrass canopy can significantly reduce soil CO₂ emissions. We conclude that further empirical evidence assessing global change threats on the seagrass carbon sink capacity is required to aid broader uptake of seagrass into blue carbon policy frameworks. The preliminary findings from this study can be used to estimate the potential risk of CO₂ emissions from seagrass habitats under threat and guide nature-based solutions for climate change mitigation.  相似文献   

Carbon Emission Evaluation in Jinan Western New District based on Multi-source Data Fusion     

XIAO Huabin  HE Xinyu  KUANG Yuanlin  WU Binglu 《资源与生态学报(英文版)》2021,12(3):346-357

Carbon emissions caused by human activities are closely related to the process of urbanization, and urban land utilization, function vitality and traffic systems are three important factors that may influence the emission levels. For clarifying the space structure of a low-carbon eco-city, and combining the concept of “Combining Assessment with Construction” to track and contrast the construction of the low-carbon eco-city, this research selects quantifiable low-carbon eco-city spatial characteristics as indicators, and evaluates and analyzes the potential carbon emissions. Taking the Jinan Western New District as an example, diversity of construction land, travel carbon emission potential, and density and accessibility of adjacent road networks in the overall urban planning were measured. After the completion of the new urban area, the evaluation mainly reflected certain factors, such as the mixed degree of urban functions, the density of urban functions, the walking distance to bus stops and the density and number of bus stops. Dividing the levels and adding equal weights after index normalization, the carbon emission potential is evaluated at the two levels of the overall and fragmented areas. The results show that: (1) The low-carbon emission potential areas in the planning scheme basically reached the planned goals. (2) There is inconsistency between districts and indicators in the planning scheme. The diversity of construction land and the accessibility of the adjacent road network are relatively small; however, there is a large difference between the travel carbon emission potential and the road network accessibility. (3) Carbon emission potential after completion did not reach the planned expectation, and the low-carbon emission potential plots were concentrated in the Changqing Old City Area and Central Area of Dangjia Town Area. (4) The carbon emission indicators varied greatly in different areas, and there were serious imbalances in the density of public transportation lines and the mixed degree of urban functions.  相似文献   

碳排放空间依赖视角下环境分权的碳排放效应   总被引：1，自引：1，他引：0  

刘贤赵  杨旭  张国桥  王天浩 《地理科学》2021,41(9):1654-1666

以环境管理人员在不同层级政府间的配置直接测算环境分权度,通过纳入财政分权指标,采用省级面板数据和动态空间计量模型从空间视角实证检验环境分权对碳排放的影响。结果表明：① 中国省域碳排放存在显著的惯性依赖和空间路径依赖,本地区碳排放的增加（降低）将带动相邻地区碳排放的上升（下降）。② 国家层面上,环境总体分权（ED）、环境行政分权（EAD）和环境监测分权（EMD）显著降低碳排放,环境监察分权（ESD）和财政分权（FD）则显著加剧碳排放。同样地,ED及其分解指标与FD的交互项也均显著促进碳排放,其影响大小与环境管理分权的类别相关。③ 不同地区环境分权的碳排放效应存在异质性。西部地区ED、EAD和EMD对碳排放产生的抑制效应明显大于东、中部地区,而东部地区ED及其分解指标与FD交互项对碳排放的抑制作用强于中、西部地区。  相似文献   

类星体HⅠ谱线的切仑柯夫红移与线强比I(Lyα)/I(Hβ)的关系     

晏明  尤峻汉  程富华 《中国天文和天体物理学报》1989,(3)

在切仑柯夫线发射理论的框架下,本文统一地讨论了类星体HI谱线的切合柯夫红移与线强比I(Lyα)/I(Hβ)之间的内在关系。忽略类星体宽线区气云外层光薄区中HI复合线的贡献,利用观测到的Lyα线相对于CIV线的相对红移,即切金柯夫红移,定出第二能级上粒子数布居R_2～0.02,利用观测的〈I(Hα)/I(Hβ)〉值定出参量x_β～14.0。在给定参量T～11000K时,HI的巴尔末线的切仑柯夫红移与线强比I(Lyα)/I(Hβ)同时与观测值相符甚佳,这对切仑柯夫线发射理论是一个有力的支持。  相似文献   

新兴的环境地貌学     

穆桂春  吴君维 《云南地理环境研究》1989,1(2):34-38

随着人类改造自然能力的增长,人类与环境地貌之间的相互作用加剧,地球表层的地貌系统在自然地域分异的基础上,出现的新的内容和特征。地貌演化不再是纯自然的过程,而且,人工地貌、人工—自然混合地貌占的比重增加了。因此,有必要对人、环境与地貌的作用机制,地貌的环境意义等问题进行研究,于是,环境地貌学应运而生。与传统地貌学不同的是,环境地貌学从人类活动与环境地貌相互作用的角度,运用系统论、综合分析方法,厚今薄古,研究现存地貌特征及后效,做出环境地貌的经济评价,探讨环境地貌的社会文化效应。本文拟对环境地貌学的产生、学科性质、研究内容和方法进行探讨,希望有助于促进环境地貌学的研究。  相似文献   

Microwave bursts from Jupiter due to K, N, P2 and S fragments     

Hari Om Vats  M. R. Deshpansde  O. P. N. Calla  N. M. Vadher  B. M. Darji  V. Sukumaran 《Earth, Moon, and Planets》1996,73(2):125-132

This article reports the observations of microwave emission from Jupiter during the impact of K, N, P2 and S fragments of the comet Shoemaker-Levy 9. The comparison of microwave bursts intensities produced by these impacts with the impact class and the size of the impactors reveals no correlation. This is in conformity with other observations at microwave frequencies and indicates that the process of burst emission is very complex. The impacts K and N produced three microwave bursts which could possibly be due to further fragmentation of these fragments. The results are discussed in the perspective of synchrotron emission from Jupiter and possible enhancements due to an increase in the radial diffusion coefficient. However, this model does not fully explain the observations.  相似文献   

太阳微波爆发中精细结构的统计研究     

傅其骏  刘玉英 《中国天文和天体物理学报》1996,(2)

本文总结了北京天文台1991年的2840MHz波段微波爆发中精细结构（FS）事件的观测．从FS的时间标度、强度、共生的微波爆发的峰值流量、FS发生在微波爆发的相位和FS与Hα耀斑的关系等方面作了统计分析．发现约67％以上的FS其持续时间为几十毫秒到几百毫秒，85％以上的FS幅度小于200sfu．讨论了FS的时标、强度及22周太阳峰年期与21周FS出现率的差别．  相似文献