Cultivated land change in the Belt and Road Initiative region   总被引：3，自引：1，他引：2  

Di Chen  Qiangyi Yu  Qiong Hu  Mingtao Xiang  Qingbo Zhou  Wenbin Wu 《地理学报(英文版)》2018,28(11):1580-1594

The Belt and Road Initiative (BRI)–a development strategy proposed by China – provides unprecedented opportunities for multi-dimensional communication and cooperation across Asia, Africa and Europe. In this study, we analyse the spatio-temporal changes in cultivated land in the BRI countries (64 in total) to better understand the land use status of China along with its periphery for targeting specific collaboration. We apply FAO statistics and GlobeLand30 (the world’s finest land cover data at a 30-m resolution), and develop three indicator groups (namely quantity, conversion, and utilization degree) for the analysis. The results show that cultivated land area in the BRI region increased 3.73×10⁴ km² between 2000 and 2010. The increased cultivated land was mainly found in Central and Eastern Europe and Southeast Asia, while the decreased cultivated land was mostly concentrated in China. Russia ranks first with an increase of 1.59×10⁴ km² cultivated land area, followed by Hungary (0.66×10⁴ km²) and India (0.57×104 km2). China decreased 1.95×10⁴ km² cultivated land area, followed by Bangladesh (–0.22×10⁴ km²) and Thailand (–0.22×10⁴ km²). Cultivated land was mainly transferred to/from forest, grassland, artificial surfaces and bare land, and transfer types in different regions have different characteristics: while large amount of cultivated land in China was converted to artificial surfaces, considerable forest was converted to cultivated land in Southeast Asia. The increase of multi-cropping index dominated the region except the Central and Eastern Europe, while the increase of fragmentation index was prevailing in the region except for a few South Asian countries. Our results indicate that the negative consequence of cultivated land loss in China might be underestimated by the domestic- focused studies, as none of its close neighbours experienced such obvious cultivated land losses. Nevertheless, the increased cultivated land area in Southeast Asia and the extensive cultivated land use in Ukraine and Russia imply that the regional food production would be greatly improved if China’ “Go Out policy” would help those countries to intensify their cultivated land use.  相似文献   

邻里建成环境对居民外出型休闲活动时空差异的影响——以广州市为例   总被引：13，自引：6，他引：7  

齐兰兰  周素红 《地理科学》2018,38(1):31-40

休闲行为的产生条件一直受到国内外地理学者的重视,邻里建成环境作为结构性制约因素,在休闲行为研究的交叉学科中开始受到重视,但是关注其对休闲行为影响的时间差异的研究严重不足;此外相关研究多从是否产生休闲行为或活动量的角度去验证,缺乏建成环境对休闲空间特征影响的衡量。基于时间地理学理论,以广州市为案例地,结合居民的出行活动日志调查与人口普查数据、土地利用数据、建筑POI普查数据,探讨居民休闲行为时空特征及居住地的邻里建成环境对其产生的影响。研究发现：工作日,居民外出型休闲活动时间呈现出高度集中特征,高度集中于12:00~14:00,活动集聚的时空区域是12:00~14:00、4 km内;休息日,居民外出型休闲活动时间集聚的集中性减弱,活动持续时间增长;活动集聚的时空区域是9:00~20:00、1 km内。邻里建成环境的不同维度指标对休闲活动距离的作用时段与影响程度存在差异。工作日上午并无影响显著的因素;中午,休闲距离主要受到道路交叉口数量和商业中心可达性的负向影响;下午,休闲距离受到道路交叉口数量先负向后正向的影响。休息日上午,休闲距离主要受开敞空间用地比例的负向影响;中午,受开敞空间用地比例、公交站点数和到最近开敞空间距离的负向影响,土地利用混合度则是呈现先正向后负向的影响;下午,受道路交叉口数量和公交站点数的负向影响、休闲设施数量的正向影响。从作用机制来看,休息日是休闲机会和时间成本作用占主导,工作日是休闲环境作用占主导。  相似文献   

地震灾害死亡人口快速评估方法对比研究   总被引：1，自引：0，他引：1  

王曦  周洪建  张弛 《地理科学》2018,38(2):314-320

中国是世界上地震活动最为频繁的国家之一,属于地震多发区。在收集分析国内外关于地震灾害死亡人口评估模型的基础上,选取10种模型以2000年以来中国典型地震灾害为案例验证其适用性。结果表明：① 对于5.7级（含）以下地震,10种模型的评估结果基本都在合理范围内,可采用各评估结果的区间值来支撑应急决策;5.7~6.6级（含）地震,10种评估方法得到的结果表现出不同程度的偏差,可采用多数评估结果指向的死亡人口数量级来支撑应急决策;6.6级以上地震,则只能采用有特定适用范围的基于结构易损性的评估结果来支撑应急决策,且也存在较大的不确定性。② 从地震灾害人员伤亡动态评估方法、地震—地质灾害死亡人口快速评估方法和快速评估软件系统方面进行了相关讨论。此研究可为地震灾害死亡人口快速评估模型的改进与发展提供借鉴。  相似文献   

长株潭地区农业功能的时空变化特征及发展策略研究   总被引：7，自引：4，他引：3  

谭雪兰  安悦  苏洋  周国华  贺艳华 《地理科学》2018,38(5):708-716

以长株潭地区23个县市区为研究区域,分别从农产品供给功能、就业和社会保障功能、生态保育功能、文化传承和休闲功能构建评价指标体系,综合运用熵值法、多指标综合评价法和农业功能变化的时空差异诊断模型等方法对长株潭地区1998~2014年农业功能的时空动态变化特征进行研究,根据各地区功能特征提出农业功能发展调控策略。研究结果表明：① 长株潭地区农产品供给功能有大幅提升,其重心有向外进一步扩散趋势;长株潭地区核心区域劳动力就业与社会保障功能下降幅度较大;大围山、罗霄山脉等山地丘陵区生态保育功能优势进一步凸显;文化传承和休闲功能部分区域获得进一步发展,但空间变化差异较小。② 研究发现不同区域农业主导功能不同,根据各地区农业功能不同优势特征,结合自身特色因地制宜发展优势农业并提出相应的优化调控对策,从而为长株潭地区农业多功能发展与功能特征的识别及确定提供理论依据。  相似文献   

六盘山东麓晚更新世以来黄土粒度指示的物源特征及演变   总被引：4，自引：0，他引：4  

王兆夺  黄春长  杨红瑾  庞奖励  查小春  周亚利 《地理科学》2018,38(5):818-826

在宁夏长城塬完整的晚更新世-全新世黄土-古土壤剖面(长城塬剖面)进行高分辨率采样,对125个样品的粒度数据做了粒度端元分析,并对各端元组分含量在地层深度尺度上做了小波分析。结果认为：端元分析法可以把代表4种不同动力的沉积端元分离出来。端元1可能代表了西风带控制下的由高空气流搬运的远源粉尘物质;端元2可能代表了沉积物沉积后在东亚夏季风作用下的风化以及成壤改造作用;端元3可能代表了后期的淋溶作用动力特征;端元4可能代表了东亚冬季风作用下典型的风成黄土粗颗粒组分特征。根据小波分析认为各端元组分含量在不同的深度上均存在着准周期变化,指示了相对应的时间尺度上古季风变化具有准周期性的特征,同时也说明了沉积剖面一直处于较为连续沉积状态,比较完整地记载了各沉积动力过程。各端元组分在不同的时间尺度上具有不同的准周期性特征。  相似文献   

江南丘陵地区乡村聚落地域分异特征研究——以湖南省为例   总被引：3，自引：2，他引：1  

谭雪兰  安悦  蒋凌霄  谭洁  周国华 《地理科学》2018,38(10):1707-1714

以江南丘陵湖南地区为研究对象,通过对18个抽样村进行实地走访与问卷调查,从乡村聚落的居住条件、居住设施和乡村居民的生产生活形态等方面,探讨江南丘陵湖南地区乡村聚落空间地域分异特征与规律。研究表明：乡村聚落研究是江南丘陵地区乡村聚落空间布局优化与调控的基础。由于地域范围广泛,区域内的资源禀赋与地域组合、经济发展基础、文化传统等条件差异悬殊,因此江南丘陵湖南地区乡村聚落发展的地域分异规律较为明显,在聚落空间格局（规模、密度、形态）、居住条件（住房面积、住房结构、建筑特色）、居住设施（道路、饮水安全、网络电视开通率等基础与公共服务设施）和生产生活形态等方面呈现出较为显著的盆地-丘陵-低山区、发达-欠发达-落后、近郊-远郊-偏远等地貌、经济、区位梯度差异。  相似文献   

青藏高原沙漠化土地空间分布及区划   总被引：4，自引：1，他引：3  

李庆  张春来  周娜  沈亚萍  伍永秋  邹学勇  李姣  贾文茹  王雪松 《中国沙漠》2018,38(4):690-700

利用野外调查数据、遥感影像和已有研究成果,构建了一套适用于青藏高原沙漠化土地的分类分级指标体系及遥感解译标志。以此为基础,选取目视解译法监测青藏高原沙漠化土地的空间分布特征。结果表明：2015年青藏高原沙漠化土地面积392 913km²,占高原土地总面积的15.1%,主要包括沙质沙漠化土地、砾质沙漠化土地和风蚀残丘3种类型。沙漠化土地以中度和轻度沙漠化土地为主,重度和极重度沙漠化土地面积仅占沙漠化土地总面积的12.2%。空间上,沙漠化土地集中分布在高原的北部和西部地区,其他地区零散分布。自东南向西北,沙漠化土地面积逐渐增大,沙漠化程度不断加重。以沙漠化土地空间分布数据（面积、类型、程度、空间特征和驱动因素）为基础,结合气候、地貌、第四纪沉积物和人类活动等数据,将青藏高原沙漠化区划分为雅鲁藏布江半干旱高山宽谷沙漠化区、藏北青南高寒高原面沙漠化区、柴达木干旱盆地沙漠化区、黄河上游半干旱河流盆地沙漠化区和“三江”流域湿润半湿润高山沙漠化区。  相似文献   

Surface-deformation monitoring in the permafrost regions over the Tibetan Plateau,using Sentinel-1 data     

ZhenMing Wu  Lin Zhao  Lin Liu  Rui Zhu  ZeShen Gao  YongPing Qiao  LiMing Tian  HuaYun Zhou  MeiZhen Xie 《寒旱区科学》2018,10(2):114-125

Differential Interferometric Synthetic Aperture Radar(D-In SAR) has been widely used to measure surface deformation over the Tibetan Plateau. However, the accuracy and applicability of the D-In SAR method are not well estimated due to the lack of in-situ validation. In this paper, we mapped the seasonal and long-term displacement of Tanggula(TGL) and Liangdaohe(LDH) permafrost regions with a stack of Sentinel-1 acquisitions using the Small Baseline Subset In SAR(SBAS-In SAR) method. In the TGL region, with its dry soils and sparse vegetation, the In SAR-derived surface-deformation trend was consistent with ground-based leveling results; long-term changes of the active layer showed a settlement rate of around 1 to 3 mm/a due to the melting of ground ice, indicating a degrading permafrost in this area. Around half of the deformation was picked up on monitoring, in contrast with in-situ measurements in LDH, implying that the D-In SAR method remarkably underestimated the surface-deformation. This phenomenon may be induced by the large soil-water content, high vegetation coverage, or a combination of these two factors in this region. This study demonstrates that surface deformation could be mapped accurately for a specific region with Sentinel-1 C-band data, such as in the TGL region.Moreover, although the D-In SAR technology provides an efficient solution for broad surface-deformation monitoring in permafrost regions, it shows a poor performance in the region with high soil-water content and dense vegetation coverage.  相似文献   

Exploring the relationship between density and completeness of urban building data in OpenStreetMap for quality estimation   总被引：1，自引：0，他引：1  

Qi Zhou 《International journal of geographical information science》2018,32(2):257-281

OpenStreetMap (OSM) is a free spatial data source based on crowd sourced data. Although the OSM data have a range of applications, such as generating 3D models, and routing and navigation, quality issues are still significant concerns when using the data. Several studies have undertaken quality assessments by comparing OSM data with reference data. However, reference data are not always available due to high costs or licensing restrictions, and very few studies have quantitatively estimated the quality of OSM data under conditions where the corresponding reference data are not available. This study proposed the use of a building density (or building coverage ratio) indicator as a proxy, and designed a series of experiments involving different study areas to quantitatively explore the relationship between building density and building completeness for OSM data in urban areas. The residuals (estimated building completeness and reference building completeness) were also analyzed. Two main results were found from the experiments. (1) There was an approximate linear relationship between building density and building completeness in the OSM data. More precisely, the building completeness of OSM data was approximately 3.4–4 times the building density of OSM data. (2) Approximately 70–80% of the absolute residuals were smaller than 10%, and 80–90% of them were smaller than 20%. This shows that, in most cases, estimated building completeness was close to the corresponding reference building completeness. Therefore, we concluded that the building density indicator is a potential proxy for the quantitative completeness estimation of OSM building data in urban areas. The limitations of using this indicator were also addressed.  相似文献   

DNQ3型能见度仪故障分析及校准方法研究          下载免费PDF全文

卢舟  王凡  王舜  刘钟中  刘志鹏  佘菁力 《中低纬山地气象》2023,47(2):114-118

为有效提高国家气象观测站能见度数据的准确性,确保能见度自动观测连续不断,对能见度仪开展故障维修、核查校准和疑误数据质控等工作显得非常重要。该文通过DNQ3型前向散射能见度仪的硬件结构和基本工作原理的介绍,以及对一些典型故障进行分析,总结出能见度仪的检测维修流程,归纳了对应的故障解决措施,凝练出该型能见度仪的核查校准和疑误数据质控方法,为一线业务人员排查能见度仪常规维护、故障排查、运行监控等提供借鉴。  相似文献