Quantifying the effectiveness of ecological restoration projects on long-term vegetation dynamics in the karst regions of Southwest China

To alleviate the severe rocky desertification and improve the ecological degradation conditions in Southwest China, the national and local Chinese governments have implemented a series of Ecological Restoration Projects (ERPs) since the late 1990s. This study proposed a remote sensing based approach to evaluate the long-term efforts of the ERPs started in 2000. The method applies a time-series trend analysis of satellite based vegetation data corrected for climatic influences to reveal human induced vegetation changes. The improved residual method is combined with statistics on the invested project funds to derive an index, Project Effectiveness Index (PEI), measuring the project effectiveness at county scale. High effectiveness is detected in the Guangxi Province, moderate effectiveness in the Guizhou Province, and low and no effectiveness in the Yunnan Province. Successful implementations are closely related to the combined influences from climatic conditions and human management. The landforms of Peak Forest Plain and Peak Cluster Depression regions in the Guangxi Province are characterized by temperate climate with sufficient rainfall generally leading to a high effectiveness. For the karst regions of the Yunnan and Guizhou Provinces with rough terrain and lower rainfall combined with poor management practices (unsuitable species selection, low compensation rate for peasants), only low or even no effect of project implementations can be observed. However, the effectiveness distribution is not homogeneous and counties with high project effectiveness in spite of complex natural conditions were identified, while counties with negative vegetation trends despite relatively favorable conditions and high investments were also distinguished. The proposed framework is expected to be of high relevance in general monitoring of the successfulness of ecological conservation projects in relation to invested funds.     

三江源生态工程实施前后长江源区宏观生态状况变化分析

基于NDVI时空序列数据,利用GLOPEM-CEVSA模型,本文估算并分析了长江源区1997-2012年植被覆盖度及植被净初级生产力时空变化特征,并在此基础上评估了生态工程实施前、后长江源区宏观生态状况变化。结果表明：工程实施后,长江源区宏观生态状况显著好转,植被覆盖度及植被净初级生产力明显增加。从多年平均值来看,工程实施后,植被覆盖度好转区域面积占植被区总面积的72.10%,净初级生产力增加区域面积占植被区总面积的73.82%;从变化趋势来看,植被覆盖度好转区域面积净增加13.02%,植被净初级生产力好转区域面积净增加24.62%。工程实施前后相比,各流域宏观生态状况恢复程度具有差异,其中楚玛尔河源头植被覆盖度上升最明显,通天河流域植被净初级生产力上升最明显。长江源区宏观生态状况的好转受益于气候的湿润化及生态工程的共同影响,若要全面有效改善仍需持续努力。     

中国大陆下扬子及邻区地壳结构基本特征：深地震测深研究综述

The Deep Seismic Sounding( DSS) projects carried out from the 1970 s in the lower Yangtze region and its neighboring area were reviewed in this paper,then the basic wave group features of those wide angle reflection / refraction record sections,and of the crustal structure are summarized. It shows that there were in total five clear wave groups on the record sections,which include the first arrival Pg,the reflection P1 from the bottom interface of the upper crust,the reflection P3 from the bottom interface of the middle crust,the strong reflection Pm from the Moho boundary,and the refraction Pn from uppermost mantle. In general,these phases are easily consistently traced and compared,despite some first arrivals being delayed or arriving earlier than normal due to the shallow sedimentary cover or bedrocks. In particular,in the Dabie Mountain region the seismic events of a few gathered shots always have weak reflection energy,are twisted,or exhibit disorganized waveforms, which could be attributed to the disruption variations of reflection depth,the broken Moho,and the discontinuity of the reflection boundary within crust. The regional crustal structures are composed of the upper,middle and lower crust,of which the middle and lower layers can be divided into two weak reflection ones. The crustal thickness of the North China and Yangtze platform are 30km- 36 km,and the Moho exhibits a flat geometry despite some local uplifts. The average pressure velocity in lower crust beneath this two tectonic area is 6. 7 ± 0. 3km / s. Nevertheless,beneath the Dabieshan area the crustal thickness is 32km- 41 km,the Moho bends down sharply andtakes an abrupt 4km- 7km dislocation in the vertical direction. The average pressure velocity in the lower crust beneath the Dabieshan area is 6. 8 ± 0. 2km / s.     

1987年来国家自然科学基金资助中的旅游地理学

中国旅游地理学研究经过30 多年的积累,已发展成一门独立的学科.本文以国家自然科学基金委员会1987 年至2013 年近30 年的旅游研究相关的资助项目为资料来源,通过历时态的方法分析了历年资助项目的数量、额度及类别的变化,从总体上了解旅游地理学研究在国家自科基金委资助下的发展情况;通过对资助项目研究内容的分析,梳理了21 个研究主题的动态变化及过程.分析表明:① 近30 年来,国家自然科学基金委对旅游研究项目资助的力度大为加强,且向青年项目和地区项目倾斜明显.基金委的资助对旅游研究起到了重要的推动作用;② 在旅游影响、旅游地演化规律、重要典型性旅游地研究、旅游理论与方法、城市旅游研究等方面获得的资助项目较多.资助项目从初期应用性研究正在走向多元、细化的深度研究阶段;③ 需反思的是,中国的旅游研究是否已形成了中国特点？在丰富的旅游现象背后,如何做出更有价值的理论构建？如何更有效地整合不同学科的研究力量？实用性强的旅游研究如何更好地为社会服务？     

国家体育场斜柱三维定位模型与测设

针对国家体育场现浇砼斜柱设计奇特,工程量大的特点,从设计参数出发,推导得出斜柱三维定位概括模型。总结施工过程中不同类型斜柱的测设方法,提出测设限差的确定原则。     

世界干热岩地热资源开发进展与地质背景分析

干热岩资源指内部不存在或仅存在少量流体,温度高于180℃的异常高温岩体,是一种极具潜力的地热资源类型。自20世纪70年代美国Fenton Hill项目实施以来,已在全球14个国家实施了41个干热岩开发项目,以干热岩储层建造和连通的目标地层周围或上部是否存在水热型储层为标准,25个属于传统意义的干热岩开发项目,16个属于增强型地热系统(Enhanced Geothermal System或Engineered Geothermal System,缩写为EGS)。从板块构造角度分析,这些干热岩开发项目主要分布在欧亚板块板内地热域、印澳板块板内地热域、东太平洋离散—汇聚板缘型地热域、西太平洋汇聚板缘型地热域和加勒比海火山活动岛弧区。按照盆地类型划分,全球干热岩开发项目所处的大地构造背景包括克拉通盆地、前陆盆地、裂谷盆地、弧前盆地、弧后盆地、近现代火山(火山带)和褶皱带地区,其中以欧洲阿尔卑斯褶皱带磨拉石盆地为代表的前陆盆地,和以欧洲阿尔卑斯褶皱带上莱茵地堑、北美新生代科迪勒拉造山带内华达盆地为代表的裂谷盆地是全球干热岩开发项目最为集中的两种盆地类型。考虑我国干热岩资源分布情况,上莱茵地堑、内华达盆地的干热岩开发历程对我国干热岩资源的勘探和开发具有一定的借鉴作用。     

西南边疆民族地区农户收入的地理影响因素分析

基于云南省红河哈尼族彝族自治州13个县(市)、273个村庄、2774户农户的微观数据集,设计了一个两水平农户收入函数模型,实证分析地理因素对农户收入影响,得出以下主要结论:①样本农户收入61.25%的总变异由农户居住村庄的外部环境导致的,农户的人均耕地面积、受过农业技术培训的人数和生产经营结构对农户收入的影响效应在农户之间存在差异,可以利用地理因素进行部分解释。②地理因素导致农户耕地、林木等资源禀赋差异,直接影响农户收入。平原村农户比山区村农户的人均纯收入高14.53%;5km以内村庄农户比5km以外村庄农户人均纯收入高30.63%。③在控制地理因素和劳动力负担系数后,农户的物质资本、生产经营结构和人力资本中的劳动力素质对农户收入具有显著的正向影响,而劳动力数量具有显著的负向影响。④地理因素影响了农户的农业基础设施条件、外出务工等,从而间接影响了农户人均耕地、受过农业技术培训劳动力人数和生产经营结构对收入的效应。并提出了增加农户收入的政策建议。     

青海省重大工程区潜在不稳定斜坡调查与灾害风险评价

文章在阐述重点工程区潜在不稳定斜坡隐患致灾问题的基础上,认为开展重点工程区潜在不稳定斜坡调查与风险评价迫在眉睫,根据青海省省情和地理要素特征,提出潜在不稳定斜坡调查与灾害风险评价的目标是对重大工程建设区的潜在不稳定斜坡进行致灾风险性评价,提出风险性管理对策;工作布署原则是＂区域展开、一般控制、重点解剖＂;工作方法是遥感解译先行、工程地质测绘为主,钻探试验为辅,在此基础上进行致灾危险性和易损性分析评价。     

区域科学学科地位、体系和前沿

区域科学虽然产生于大约半个世纪以前,但其在中国的正式亮相则是９０年代初的事情。通过论述影响区域科学在中国发展的几个基本理论问题,即：通过弄清区域科学与地理学、经济学、管理科学学学科的关系进一步明确区域科学独立的学科地位,明晰区科学学科划分,探讨新区域科学的特点,指出其前沿领域。     

卫星降水产品评价研究的演进脉络与前沿进展

卫星遥感观测技术的不断发展,为全球降水准确定量观测提供新的手段,应用卫星降水产品的前提是进行地区的适用性评价.为了解卫星降水产品评价的研究现状和热点,以Web of Sci-ence数据库核心合集中1998—2020年752篇文献作为研究对象,利用文献计量和网络分析的方法剖析卫星降水产品评价研究的演变趋势、合作关系和研...