BS-ACEBOC: a generalized low-complexity dual-frequency constant-envelope multiplexing modulation for GNSS

GPS Solutions - In order to satisfy the need for combining signals in a constant-envelope modulation, we propose a new dual-frequency constant-envelope modulation (DCEM), called asymmetric...     

Analysis of geometry-free residuals in case of traveling ionosphere disturbances and their impact cycle slip detection

GPS Solutions - We discuss the impact of a traveling ionospheric disturbance (TID) on cycle slip detection for the geometry-free (GF) combination. Based on the GF combination algorithm, we deduce...     

中美国土资源领域合作评述与展望

国土资源部建立以来,国土资源系统相关单位与美国有关政府部门、科研机构及高校开展了长期友好合作,建立了良好的合作机制,并通过政策对话、项目合作、技术交流、培训、研讨等方式开展交流合作,取得了重要的成果.本文对中美两国国土资源领域的重点合作进行了研究,介绍了两国国土资源领域的合作现状,分析了中美两国国土资源领域的合作特点,总结了合作成果,并对进一步开展合作进行了展望.     

中法国土资源领域合作评述与展望

中法在国土资源领域的合作起步早,起点高.双方高层保持良好互动,重大合作项目开展顺利,科研和技术人员合作成果丰硕.本文从法国国土资源的基本情况、管理体系、人员交流情况以及重大合作项目等几个方面介绍了中法合作现状,并对未来合作进行了展望.     

国土资源部内网网站内容建设研究与实践

国土资源部内网网站经过多年的发展,形成了一套完善的内容体系和信息维护机制.本文详解了国土资源部内网网站内容建设原则、总体架构、信息分类、栏目规划、维护模式等,总结了网站内容建设所取得的成效.     

中国省区间贸易隐含PM2.5的测算及其空间转移特征

针对不同区域实行“共同而又有区别”的污染治理政策是实现区域联防治理大气污染的有效措施,而随着省际贸易加强,难免导致污染物在不同区域间的转移。本文采用区域间投入产出模型,对中国30省区间省际贸易隐含PM_2.5进行核算。结果表明,省际贸易隐含PM_2.5约占总PM_2.5排放的1/3,经济危机使得省际贸易隐含PM_2.5量变小,但贸易隐含PM_2.5在以生产计算的PM_2.5排放中的作用在增大。东部省区的省际调出贸易隐含PM_2.5主要由最终消费部分导致,而中、西、东北省区则主要为中间投入部分导致,在控制贸易隐含排放时,需对不同调出类型省区采用不同的控制方法。省际调入贸易隐含PM_2.5主要由中间投入过程贸易隐含PM_2.5构成,越来越多的产品在不同省区间共同生产完成,区域联合治污显得尤为必要。东北、西部、中部省区由固定资本形成导致的省际贸易隐含PM_2.5比例要高于东部省区,可见政策导向也是造成贸易隐含排放的原因之一。需重点控制省际贸易隐含PM_2.5排放量较高建筑业、机械设备制造业和其他服务业。除河北、山东外,东部省区均为省际贸易隐含PM_2.5净调入省份,中、西部、东北省区中则多为省际贸易隐含PM_2.5净调出省份。经济危机使得省际间净贸易隐含PM_2.5的转移量变小,但并未改变其转移趋势。净调入省区需相应的补偿净调出省区,或对其进行技术转移。     

空间相互作用模型中的目的地竞争效应 ——基于中国城市间铁路客流数据的实证研究

目的地竞争模型是空间相互作用领域的重要进展之一,但其有效性尚未得到一致认可,且缺乏基于中国的实证依据。基于中国2010年城市间铁路客流数据,采用目的地竞争模型进行实证分析,并与传统空间相互作用模型相比较,以检验目的地竞争模型在实际应用中的有效性。结果表明：① 空间结构对中国城市间铁路客流存在显著影响,目的地之间存在较强的竞争效应;② 目的地竞争模型的引入显著地减弱了距离衰减参数的空间自相关程度,较大程度上改善了传统空间相互作用模型的距离衰减参数标定偏误问题;③ 既有研究中在区域尺度下对传统空间相互作用模型（即重力模型）参数的标定及实证分析可能会存在偏误,目的地竞争模型这一改进模型具备应用价值。     

基于消费责任制的碳排放核算及全球环境压力

因区域间贸易而转移的碳排放对于全球各个国家或者地区的碳排放核算及其减排责任划分具有重要而深远的影响。通过构建多区域投入产出分析模型和基于扩展的STIRPAT模型,本文核算了全球39个主要国家基于消费责任制的碳排放,并在此基础上深入探讨了全球环境压力的影响因素问题。研究发现：首先,从以净流出为主的中国和俄罗斯来看,尽管贸易给这些地区带来了大量的资源,但随之会产生严重的区域生态环境问题。而对于美国和欧盟等地区来说,这些国家或者地区通过全球贸易规避了大量的碳减排责任。此外,在全球贸易中,区域净流出的贸易隐含碳排放越小,基于消费责任制核算的区域碳排放量就越大,故而在全球减排目标分配中承担的减排任务也需相应地增加。全球贸易隐含碳排放净流出量较大的地区主要位于亚洲和东欧等地,而净流出量最小的地区主要是以西欧和北美等高度发达的经济体为主。其次,就基于消费责任制核算下的全球环境压力而言,人口因素和富裕程度是导致全球环境压力不断增加的两个重要因素,而提高生产技术水平以及逐渐提高清洁能源在总能源消费中的比重是推动全球节能减排、缓解全球环境压力的有效途径。     

Regional differentiation of ecological conservation and its zonal suitability at the county level in China

China’s investments, financial incentives and deductions in terms of ecological conservation are based at the county level. Therefore, the monitoring and assessment of the effects of ecological conservation at the county level is important to provide a scientific basis for the assessment of the ecological and environmental quality at the county scale. This paper quantitatively estimated the dynamics of high-quality ecosystems and vegetation coverage over the past 15 years, and their relationships with the number of ecological conservation programs at the county level were analyzed. Then, the effects of ecological conservation measures on ecological changes at the county level and their regional suitability were assessed and discussed. The results showed that counties with a percentage of high-quality ecosystems greater than 50% were primarily distributed in northeastern China, southern subtropical China and the southeastern Qinghai-Tibet Plateau, and those with a percentage lower than 20% were mostly distributed in northwestern China, the southwestern karst region and the North China Plain. In recent decades, ecological conservation has focused on ecologically fragile regions; more than five ecological conservation programs have been implemented in most counties of the Three River Source Region in Qinghai Province, southeastern Tibet, western Sichuan, the Qilian Mountains, southern Xinjiang and other western regions, while only one or zero have been implemented in the eastern coastal area of China. Over the past 15 years, the proportional area of high-quality ecosystems has increased in approximately 53% of counties. The vegetation coverage of counties in the Loess Plateau, Huang-Huai-Hai Plain, Beijing-Tianjin-Hebei (Jing-Jin-Ji), Sichuan-Guizhou-Chongqing, and Guangdong-Guangxi provincial-level areas has increased significantly. However, it decreased in northern Xinjiang, central Tibet, central and eastern Inner Mongolia, the Yangtze River Delta and other regions. The relationships between the numbers of ecological conservation programs and the indicators of ecosystem restoration response, such as high-quality ecosystem and vegetation coverage, do not show positive correlations. These results suggest that ecological conservation programs should be planned and implemented according to the distribution patterns of high-quality ecosystems and that restoration measures such as afforestation should follow natural principles and regional differentiation under the background of climate change.     

“丝绸之路”模态与东亚夏季环流的关系分析

基于1979—2015年ERA-Interim再分析资料,分析了夏季"丝绸之路"(the Silk Road,即SR)模态与东亚地区大气环流之间的联系,结果表明:在SR模态正异常年,200 hPa亚洲急流在东亚地区比较弯曲,在中国新疆和环渤海地区500 hPa上分别有一个高度脊和一个高度槽,在蒙古国、中国内蒙古以及日本以东500 hPa上有显著的位势高度正异常,风场异常与高度场配合较好。在对流层中低层的中国北方,有明显的下沉气流,在中国内蒙古、蒙古国以及日本以东,出现位涡负异常,而在朝鲜半岛附近,则有位涡正异常出现。中国环渤海地区降水偏少,而日本大部分地区降水偏多。在SR模态负异常年,200 hPa急流相对平直且更强,500 hPa的波列特征比正异常年更加显著,在中国内蒙古和蒙古国、朝鲜半岛、日本以东分别有"-、+、-"分布的位势高度场异常。与正异常年相比,位于东亚135°E附近的正异常中心变得显著,在该异常中心的西侧和东侧分别有上升和下沉异常气流,对应在朝鲜半岛和中国东北附近有较大的位涡负异常。在环渤海、朝鲜半岛南部和日本、日本以东洋面上,降水分别出现偏多、偏少和偏多现象。