期刊文献+
共找到20篇文章
< 1 >
每页显示 20 50 100
Experimental Research on Quantitative Inversion Models of Suspended Sediment Concentration Using Remote Sensing Technology 被引量:1
1
作者 Wang Yanjiao Yan Feng +1 位作者 Zhang Peiqun Dong Wenjie 《Chinese Geographical Science》 SCIE CSCD 2007年第3期243-249,共7页
Research on quantitative models of suspended sediment concentration(SSC)using remote sensing technology is very important to understand the scouring and siltation variation in harbors and water channels.Based on labor... Research on quantitative models of suspended sediment concentration(SSC)using remote sensing technology is very important to understand the scouring and siltation variation in harbors and water channels.Based on laboratory study of the relationship between different suspended sediment concentrations and reflectance spectra measured synchronously,quantitative inversion models of SSC based on single factor,band ratio and sediment parameter were developed,which provides an effective method to retrieve the SSC from satellite images.Results show that the b1(430-500nm)and b3(670-735nm)are the optimal wavelengths for the estimation of lower SSC and the b4(780-835nm)is the optimal wavelength to estimate the higher SSC.Furthermore the band ratio B2/B3 can be used to simulate the variation of lower SSC better and the B4/B1 to estimate the higher SSC accurately.Also the inversion models developed by sediment parameters of higher and lower SSCs can get a relatively higher accuracy than the sin-gle factor and band ratio models. 展开更多
关键词 悬浮沉淀物浓缩 光谱反射 反转模式 遥感系统
下载PDF
Diagenesis and Diagenetic Evolution of Deltaic and Neritic Gas-Bearing Sandstones in the Lower Mingyuefeng Formation of Paleogene, Lishui Sag, East China Sea Shelf Basin: Implications for Depositional Environments and Sequence Stratigraphy Controls 被引量:5
2
作者 XU Fa ZHANG Penghui +7 位作者 ZHANG Jinliang LIU Jinshui HOU Guowei ZHANG Ming LI Jingzhe LIU Shasha GUO Jiaqi MENG Ningning 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第5期1625-1635,共11页
Gas-bearing deposits in the Lower Mingyuefeng Formation of Paleogene, Lishui Sag, East China Sea Shelf Basin consist of shoreface sandstones of the highstand systems tract(HST) and transgressive systems tract(TST)... Gas-bearing deposits in the Lower Mingyuefeng Formation of Paleogene, Lishui Sag, East China Sea Shelf Basin consist of shoreface sandstones of the highstand systems tract(HST) and transgressive systems tract(TST), and deltaic sandstones of the lowstand systems tract(LST) and falling stage systems tract(FSST).Detailed petrographic observations suggest that the diagenetic features and related evolution of these deposits cannot be simply characterized and demonstrated in the depth domain.However, the occurrence of diagenetic minerals systematically depends on the studied interval within the HST, TST, LST, and FSST; therefore, diagenesis in this region can be better constrained when studied in the context of the depositional environments and sequence stratigraphic framework.The eogenetic processes in such settings include:(1) microcrystalline siderite precipitated as concretions in almost all environments and systems tracts, which inhibited further mechanical compaction;(2) grain dissolution and kaolinitization occurred in shoreface HST sandstones and deltaic LST and FSST sandstones;(3) glaucony was locally observed, which did not clearly reflect the controls of facies or sequence stratigraphy; and(4) cementation by pyrite aggregates occurred in the shoreface HST sandstones and deltaic LST sandstones.The mesogenetic diagenesis includes:(1) partial conversion of kaolinite into dickite in deltaic LST sandstones, and minor chlorite cementation in deltaic FSST sandstones;(2) transformation of kaolinite into illite and quartz cementation in deltaic LST and FSST sandstones;(3) frequent precipitation of ankerite and ferroan calcite in shoreface TST sandstones and early HST sandstones, forming baffles and barriers for fluid flow, with common calcite in shoreface HST sandstones as a late diagenetic cement; and(4) formation of dawsonite in the deltaic LST and FSST sandstones, which is interpreted to be a product of the invasion of a CO2-rich fluid, and acts as a good indicator of CO2-bearing reservoirs.This study has thus constructed a reliable conceptual model to describe the spatial and temporal distribution of diagenetic alterations.The results may provide an entirely new conceptual framework and methodology for successful gas exploration in the continental margins of offshore China, thus allowing us to predict and unravel the distribution and quality evolution of clastic reservoirs at a more detailed and reliable scale. 展开更多
关键词 diagenetic alteration depositional environment sequence stratigraphy reservoir quality PALEOGENE East China Sea Shelf Basin
下载PDF
Object-oriented Urban Dynamic Monitoring——A Case Study of Haidian District of Beijing 被引量:9
3
作者 An Kai Zhang Jinshui Xiao Yu 《Chinese Geographical Science》 SCIE CSCD 2007年第3期236-242,共7页
It is crucial to conduct the land use/cover research to obtain the global change information.Urban area is one of the most sensitive areas in land use/cover change.Therefore land use/cover change in urban areas is ver... It is crucial to conduct the land use/cover research to obtain the global change information.Urban area is one of the most sensitive areas in land use/cover change.Therefore land use/cover change in urban areas is very im-portant in global change.It is vital to incorporate the information of urban land use/cover change into the process of decision-making about urban area development.In this paper,a new urban change detection approach,urban dynamic monitoring based on objects,is introduced.This approach includes four steps:1)producing multi-scale objects from multi-temporal remotely sensed images with spectrum,texture and context information;2)extracting possible changed objects adopting object-oriented classification;3)obtaining shared objects as the basic units for urban change detection;4)determining the threshold to segment the changed objects from the possible changed objects using Otsu method.In this paper,the object-based approach was applied to detecting the urban expansion in Haidian District,Beijing,China with two Landsat Thematic Mapper(TM)data in 1997 and 2004.The results indicated that the overall accuracy was about 84.83%,and Kappa about 0.785.Compared with other conventional approaches,the object-based approach was advantageous in reducing the error accumulation of image classification of each datum and in independence to the radiometric correction and image registration accuracy. 展开更多
关键词 北京 城市动态监测 目标导向 遥感系统
下载PDF
Seismic sedimentology of conglomeratic sandbodies in lower third member of Shahejie Formation (Palaeogene) in Shengtuo area, East China 被引量:2
4
作者 袁勇 张金亮 +2 位作者 李存磊 孟宁宁 李岩 《Journal of Central South University》 SCIE EI CAS 2014年第12期4630-4639,共10页
The sand-conglomerate fans are the major depositional systems in the lower third member of Shahejie Formation in Shengtuo area, which formed in the deep lacustrine environment characterized by steep slope gradient, ne... The sand-conglomerate fans are the major depositional systems in the lower third member of Shahejie Formation in Shengtuo area, which formed in the deep lacustrine environment characterized by steep slope gradient, near sources and intensive tectonic activity. This work was focused on the sedimentary feature of the glutenite segment to conduct the seismic sedimentology research. The near-shore subaqueous fans and its relative gravity channel and slump turbidite fan depositions were identified according to observation and description of cores combining with the numerous data of seismic and logging. Then, the depositional model was built depending on the analysis of palaeogeomorphology. The seismic attributes which are related to the hydrocarbon but relative independent were chosen to conduct the analysis, the reservoir area of the glutenite segment was found performing a distribution where the amplitude value is relatively higher, and finally the RMS amplitude attribute was chosen to conduct the attribute predicting. At the same time, the horizontal distribution of the sedimentary facies was analyzed qualitatively. At last, the sparse spike inversion method was used to conduct the acoustic impedance inversion, and the inversion result can distinguish glutenite reservoir which is greater than 5 m. This method quantitatively characterizes the distribution area of the favorable reservoir sand. 展开更多
关键词 砂砾岩储层 地震属性 胜坨地区 沙河街组 沉积学 中国东部 古近纪 反演方法
下载PDF
Composition and Provenance of Sandstones and Siltstones in Paleogene,Huimin Depression,Bohai Bay Basin,Eastern China 被引量:1
5
作者 张金亮 张鑫 《Journal of China University of Geosciences》 SCIE CSCD 2008年第3期252-270,共19页
This study was conducted to distinguish the compositions and provenance of sandstones and siltstones in the Ek1-Es3 members of Huimin (惠民) depression. The samples have been analyzed for petrographic, major element... This study was conducted to distinguish the compositions and provenance of sandstones and siltstones in the Ek1-Es3 members of Huimin (惠民) depression. The samples have been analyzed for petrographic, major element and selected trace element compositions (including REE). The results show that the sandstones from the first member of Kongdian (孔店) Formation (Ek1) have higher quartz compositions than those from the fourth member (Es4) and the third member (Es3) of Shahejie (沙河街) Formation. The alkali feldspar/plagioclase ratio in the A-CN-K diagrams decreases in the order Ek1〉Es4〉Es3, which suggests that the Ek1 member had a more alkali feldspar-rich granitoid source and more intense weathering of the source than the Es4 and Es3 members. The mineral distributions in the A-CN-K diagrams also indicate that the sandstones and siltstones in the three members underwent K-metasomatism. Extrapolation of the sandstones and siltstones back to the plagioclase-alkali feldspar line in the A-CN-K diagram suggests a high average plagioclase to alkali feldspar ratio in the provenance (tonalite to granite). In addition, the chemical index of weathering (CIW) and chemical index of alteration (CIA) parameters of the sandstones and siltstones suggest that the weathering of the first cycle material was intense, and the CIW decreases in the order Ek1〉Es4〉Es3 Trace element ratios suggest all the sedimentary rocks were mostly derived from granitoids. Elemental ratio plots (e.g., Th/Sc vs. Eu/Eu^*) of sandstones and siltstones suggest a mix of a granodiorite-tonalite source as a source of the sandstones and siltstones. The sandstones and siltstones of Es3 and Es4 members also contain higher Eu/Eu* and lower Th/Sc ratios than the sandstones and siltstones of Ek1 member. As is consistent with the petrography, it suggests that the sandstones and siltstones of Es3 and Es4 members are derived from a source with less granite and more granodiorite-tonalite than the sandstones and siltstones of Ek1 member. 展开更多
关键词 SILTSTONE sandstone PROVENANCE trace element REE Huimin depression.
下载PDF
Research of the Response of Ecosystem to LUCC in Miyun County,Beijing:Based on Ecosystem Services Valuation
6
作者 Xu Xu Li Xiaobing Yu Jingjing 《Chinese Journal of Population,Resources and Environment》 2012年第3期84-89,共6页
Miyun County,located in the northeast of Chinese capital Beijing,was underwent remarkable variations in land use in recent years.This paper aimed to detect changes in land use of Miyun from 1997 to 2005,and to qualify... Miyun County,located in the northeast of Chinese capital Beijing,was underwent remarkable variations in land use in recent years.This paper aimed to detect changes in land use of Miyun from 1997 to 2005,and to qualify the response of ecosystem to LUCC based on ecosystem services valuation.With two-periods TM images,we got land use change data,and then ecosystem services values were calculated using ecosystem services valuation coefficients proposed by Chinese scholar Xie Gaodi.Results showed that water area,farm land and unused land decreased while residential land,forest land,grassland and orchard land increased during the study period.The loss of ESV was RMB 206 million and the main reason was the decrease of water area and farm land area.As for spatial variation,there were most dramatically land use change and ESV decline in reservoir ecological protection region.The coefficient sensitivity analysis indicates that valuation coefficients used in the study are suitable and results are reasonable.The driving forces of ESV loss were rapid population growth and economic development.More work should be done to make eco-environment stay healthy. 展开更多
关键词 生态系统服务功能 土地利用变化 价值评估 密云县 生态效应 北京 生态系统服务价值 TM遥感影像
下载PDF
Scenario analysis for the energy demand and carbon emissions in low carbon city 被引量:3
7
作者 ZHU Jing LIU Xue-min PANG Wei-hong 《Ecological Economy》 2015年第2期130-138,共9页
This paper takes the climate change and low carbon economy development as the study background, based on the analysis of energy demand and carbon emissions status, which is aimed to provide the low carbon development ... This paper takes the climate change and low carbon economy development as the study background, based on the analysis of energy demand and carbon emissions status, which is aimed to provide the low carbon development path in Chinese cities. The method of scenario analysis can be used to predict long-term strategy for the uncertainty future development, and it was introduced to the field of social forecasting and public policy research, such as the environmental strategic planning, policy analysis, and support of decision in resource management, which can be used to explore the possible development trend and target of the results from the macro perspective. Scenario analysis has been gradually applied to the study area on low carbon economy, energy forecasting and other fields in recent years, and there have been many research results in different aspects. This paper takes the scenario analysis as basic study theory, spreading out the present situation of its application in low carbon city and some issues that need further study. As a tool for predicting the future development in low carbon city, the method of scenario analysis has been providing a powerful reference for policies and their executants. 展开更多
关键词 low CARBON CITY SCENARIO analysis energy demand CARBON emissions FORECAST
下载PDF
An Information Diffusion Technique for Fire Risk Analysis 被引量:1
8
作者 刘静 黄崇福 《Journal of Donghua University(English Edition)》 EI CAS 2004年第3期54-57,共4页
There are many kinds of fires occurring under different conditions. For a specific site, it is difficult to collect sufficient data for analyzing the fire risk. In this paper, we suggest an information diffusion techn... There are many kinds of fires occurring under different conditions. For a specific site, it is difficult to collect sufficient data for analyzing the fire risk. In this paper, we suggest an information diffusion technique to analyze fire risk with a small sample. The information distribution method is applied to change crisp observations into fuzzy sets, and then to effectively construct a fuzzy relationship between fire and surroundings. With the data of Shanghai in winter, we show how to use the technique to analyze the fire risk. 展开更多
关键词 信息传播 起火原因 模糊关系 火灾事故 技术分析
下载PDF
Comprehensive analysis of the impact of climatic changes on Chinese terrestrial net primary productivity 被引量:14
9
作者 ZHU WenQuan PAN YaoZhong YANG XiaoQiong SONG GuoBao 《Chinese Science Bulletin》 SCIE EI CAS 2007年第23期3253-3260,共8页
Recent climatic changes have affected terrestrial net primary productivity (NPP). This paper presents an investigation of the impact of climatic changes on Chinese terrestrial vegetation NPP by analyzing 18 years’ (1... Recent climatic changes have affected terrestrial net primary productivity (NPP). This paper presents an investigation of the impact of climatic changes on Chinese terrestrial vegetation NPP by analyzing 18 years’ (1982 to 1999) climatic data and satellite observations of vegetation activity. Results indicate that climatic changes in China have eased some critical climatic constraint on plant growth. (1) From 1982 to 1999, modeled NPP increased by 1.42%·a-1 in water-limited regions of Northwest China, 1.46%·a-1 in temperature-limited regions of Northeast China and Tibet Plateau, and 0.99%·a-1 in radia- tion-limited regions of South China and East China. (2) NPP increased by 24.2%, i.e. 0.76 petagram of carbon (Pg C) over 18 years in China. Changes in climate (with constant vegetation) directly contrib- uted nearly 11.5% (0.36 Pg C). Changes in vegetation (with constant climate) contributed 12.4% (0.40 Pg C), possibly as a result of climate-vegetation feedbacks, changes in land use, and growth stimula- tion from other mechanisms. (3) Globally, NPP declined during all three major El Ni-o events (1982 to 1983, 1987 to 1988, and 1997 to 1998) between 1982 and 2000, but Chinese vegetation productivity re- sponded differently to them because of the monsoon dynamics. In the first three events (1982 to 1983, 1987 to 1988, and 1992), Chinese vegetation NPP declined, while in the later two events (1993, 1997 to 1998) increasing obviously. 展开更多
关键词 气候变化 遥控技术 中国 实验数据
原文传递
Spatiotemporal changes of cold surges in Inner Mongolia between 1960 and 2012 被引量:11
10
作者 LIU Xianfeng 《Journal of Geographical Sciences》 SCIE CSCD 2015年第3期259-273,共15页
In this study, we analyzed the spatiotemporal variation of cold surges in Inner Mongolia between 1960 and 2012 and their possible driving factors using daily minimum temperature data from 121 meteorological stations i... In this study, we analyzed the spatiotemporal variation of cold surges in Inner Mongolia between 1960 and 2012 and their possible driving factors using daily minimum temperature data from 121 meteorological stations in Inner Mongolia and the surrounding areas. These data were analyzed utilizing a piecewise regression model, a Sen+Mann- Kendall model, and a correlation analysis. Results demonstrated that (1) the frequency of single-station cold surges decreased in Inner Mongolia during the study period, with a linear tendency of -0.5 times/10a (-2.4 to 1.2 times/10a). Prior to 1991, a significant decreasing trend of-1.1 times/10a (-3.3 to 2.5 times/10a) was detected, while an increasing trend of 0.45 times/10a (-4.4 to 4.2 times/10a) was found after 1991. On a seasonal scale, the trend in spring cold surges was consistent with annual values, and the most obvious change in cold surges occurred during spring. Monthly cold surge frequency displayed a bimodal structure, and November witnessed the highest incidence of cold surge. (2) Spatially, the high incidence of cold surge is mainly observed in the northern and central parts of Inner Mongolia, with a higher occurrence observed in the northern than in the central part. Inter-decadal character- istic also revealed that high frequency and low frequency regions presented decreasing and increasing trends, respectively, between 1960 and 1990. High frequency regions expanded after the 1990s, and regions exhibiting high cold surge frequency were mainly distributed in Tulihe, Xiao'ergou, and Xi Ujimqin Banner. (3) On an annual scale, the cold surge was dominated by AO, NAO, CA, APVII, and CQ. However, seasonal differences in the driving forces of cold surges were detected. Winter cold surges were significantly correlated with AO, NAO, SHI, CA, TPI, APVII, CW, and IZ, indicating they were caused by multiple factors. Au- tumn cold surges were mainly affected by CA and IM, while spring cold surges were significantly correlated with CA and APVII. 展开更多
关键词 cold surge piecewise regression Sen Mann-Kendall spatiotemporal variations influencing factors Inner Mongolia
原文传递
The progress and prospects of nebkhas in arid areas 被引量:9
11
作者 DU Jianhui YAN Ping DONG Yuxiang 《Journal of Geographical Sciences》 SCIE CSCD 2010年第5期712-728,共17页
Nebkhas are often extensively distributed in arid and semi-arid areas, and play an important role in the stabilization of ecological environment in these areas. This paper reviews the following aspects, including form... Nebkhas are often extensively distributed in arid and semi-arid areas, and play an important role in the stabilization of ecological environment in these areas. This paper reviews the following aspects, including formation and succession, spatial distribution, shape and surface airflow characteristics, balance between erosion and deposition, ecological and physiological characteristics of vegetation, response to precipitation and groundwater, soil properties as well as the protection measures. We found that nebkhas were studied without differentiation of succession periods, and shape characteristics, surface airflow, soil proper- ties as well as vegetation dynamics in different succession periods were not fully understood, which made it difficult to explain the succession dynamics of nebkhas and its affecting factors. Previous studies of nebkhas were over-emphasized for its role as an indicator of land deg- radation, while its ecological functions in degraded ecosystems were neglected, which was unfavorable for the ecological restorations in arid and semi-arid areas. Future studies should pay more attention to the variation of vegetation, soil as well as hydrological process in the succession of nebkhas and its interaction between different influencing factors. In addition, positive role of nebkhas in degraded ecosystems in arid and semi-arid areas should be fully discussed. According to the data got from the above, effective protection measures of nebkhas should be explored. 展开更多
关键词 NEBKHAS succession period protection measures ecological function
原文传递
Pharmacokinetics and brain distribution differences of baicalin in rat underlying the effect of Panax notoginsenosides after intravenous administration 被引量:3
12
作者 YANG Yan-Fang LI Zhi +2 位作者 XIN Wen-Feng WANG Yong-Yan ZHANG Wen-Sheng 《Chinese Journal of Natural Medicines》 SCIE CAS CSCD 2014年第8期632-640,共9页
Baicalin(BA) is the most well-known flavonoid present in Radix Scutellariae. The aim of this study was to explore whether the pharmacokinetic behavior of BA in rat brain can be affected by Panax notoginsenosides(PNS),... Baicalin(BA) is the most well-known flavonoid present in Radix Scutellariae. The aim of this study was to explore whether the pharmacokinetic behavior of BA in rat brain can be affected by Panax notoginsenosides(PNS), and to assess the possible mechanism for the observed effects. Specific HPLC and HPLC/MS/MS methods were developed and validated for the determination of BA in the rat plasma and brain using carbamazepine as an internal standard. BA was found to enter rat brain quickly after a single intravenous dose. When co-administered with PNS, clearance(CL) of BA from rat plasma decreased by 50.00%, while the area under the curve AUC0-t and AUC0-∞ increased 94.69% and 87.68%, respectively. On the other hand, some pharmacokinetic parameters of BA in rat brain had obvious differences after PNS was administered, such as an increase in Tmax from 5 min to 15 min, an increase in AUC0-t and AUC0-∞ by 42.75% and 29.39%, respectively, as well as a decrease in CL by 27.95%. Together, these results indicate that PNS can decrease the elimination rate of BA from rat plasma, promote the penetration of BA into rat brain, increase the concentration and slow down the elimination of BA from rat brain. The data provide important information that compatibility with PNS can promote the consequent effects of BA for the treatment of encephalopathy. 展开更多
关键词 BAICALIN Panax notoginsenosides Rat plasma Rat brain PHARMACOKINETICS HPLC/MS/MS
原文传递
Spatial distribution regularity and influence factors of population density in the LRGR 被引量:4
13
作者 SONG GuoBao LI ZhengHai +5 位作者 BAO YaJing LU HaiYan GAO JiXi WANG HaiMei XU Tian CHENG Yan 《Chinese Science Bulletin》 SCIE EI CAS 2007年第A02期90-97,共8页
联合 GIS 措施和统计方法,这份报纸选择地文学的因素和气候的因素在 LRGR 在人口密度上学习影响力量和它所有因素的功能的形式。另外,这份报纸与影响人口密度分发的因素在 LRGR 模仿人口密度分发的地位。调查结果显示下列情形:(1 ) ... 联合 GIS 措施和统计方法,这份报纸选择地文学的因素和气候的因素在 LRGR 在人口密度上学习影响力量和它所有因素的功能的形式。另外,这份报纸与影响人口密度分发的因素在 LRGR 模仿人口密度分发的地位。调查结果显示下列情形:(1 ) 所有自然因素在 LRGR,而是影响程度和形式在人口密度的空间模式上有影响是相当不同的。地文学的因素和交通网络密度在人口密度上有大影响,当象温度和降水的如此的因素几乎没在人口分发上有小影响时。在人口密度和交通网络密度之间的关系假定否定、积极的线性关联趋势,当水系统密度和斜坡的影响看起来独立是指数的函数和对数函数时。(2 ) 人口在整个 LRGR 被散布并且当因为自然条件的影响的不可分的散布和本地集中,呈现如此的特征。因此,一条高人口密度带在 LRGR 的中间被形成了,并且一个高人口密度补丁在 LRGR 的南方形成。(3 ) 在 LRGR 在人口密度和人的活动索引(HAI ) 之间有一种好线性回归关系,它反映在场的那个人口密度罐头在 LRGR 的自然生态系统上的人工的骚乱。(4 ) 人口密度的增加导致 NDVI 索引的减少。 展开更多
关键词 纵向岭谷区 空间 分配模式 影响因素
原文传递
Similarities and differences of city-size distributions in three main urban agglomerations of China from 1992 to 2015: A comparative study based on nighttime light data 被引量:15
14
作者 高宾 黄庆旭 +1 位作者 何春阳 窦银银 《Journal of Geographical Sciences》 SCIE CSCD 2017年第5期533-545,共13页
Comparing the city-size distribution at the urban agglomeration(UA) scale is important for understanding the processes of urban development. However, comparative studies of city-size distribution among China's thre... Comparing the city-size distribution at the urban agglomeration(UA) scale is important for understanding the processes of urban development. However, comparative studies of city-size distribution among China's three largest UAs, the Beijing-Tianjin-Hebei agglomeration(BTHA), the Yangtze River Delta agglomeration(YRDA), and the Pearl River Delta agglomeration(PRDA), remain inadequate due to the limitation of data availability. Therefore, using urban data derived from time-series nighttime light data, the common characteristics and distinctive features of city-size distribution among the three UAs from 1992 to 2015 were compared by the Pareto regression and the rank clock method. We identified two common features. First, the city-size distribution became more even. The Pareto exponents increased by 0.17, 0.12, and 0.01 in the YRDA, BTHA, and PRDA, respectively. Second, the average ranks of small cities ascended, being 0.55, 0.08 and 0.04 in the three UAs, respectively. However, the average ranks of large and medium cities in the three UAs experienced different trajectories, which are closely related to the similarities and differences in the driving forces for the development of UAs. Place-based measures are encouraged to promote a coordinated development among cities of differing sizes in the three UAs. 展开更多
关键词 city-size distribution comparative study nighttime light data rank clock urban agglomeration
原文传递
Analysis of land use change and its driving force in the Longitudinal Range-Gorge Region 被引量:2
15
作者 LI ZhengHai SONG GuoBao +5 位作者 LU HaiYan BAO YaJing GAO JiXi WANG HaiMei XU Tian CHENG Yan 《Chinese Science Bulletin》 SCIE EI CAS 2007年第A02期10-20,共11页
关于陆地使用度,陆地使用变化率以及各种各样的陆地使用的地区性的差别的研究录入西南纵的范围峡区域(LRGR ) 被执行了在上地区性并且县规模。从社会经济的看法,我们也在研究区域分析了陆地使用变化的开车机制和各种各样的驱动力的相... 关于陆地使用度,陆地使用变化率以及各种各样的陆地使用的地区性的差别的研究录入西南纵的范围峡区域(LRGR ) 被执行了在上地区性并且县规模。从社会经济的看法,我们也在研究区域分析了陆地使用变化的开车机制和各种各样的驱动力的相应空间范围。研究结果显示在地区性的规模上,农田,森林和草地在 LRGR,和草地严厉地衰退的陆地使用表演的结构的变化填写陆地使用的主要身体,农田增加和森林保持稳定。在县规模上,陆地使用被那陆地使用水平描绘是相对低的,并且陆地使用度,全面变化率和相对变化在不同陆地使用类型之中评价仍然存在。由分析,在 LRGR 的陆地使用变化被投资主要驾驶人力和物理资源,社会经济产量水平,自然灾难骚乱的紧张和工人的教育水平的紧张。然而, regionalism 在不同驱动力类型的影响范围存在。 展开更多
关键词 分析方法 动力系统 纵向岭谷区 土地
原文传递
Diverse effects of crop distribution and climate change on crop production in the agro-pastoral transitional zone of China
16
作者 Jianmin QIAO Deyong YU +1 位作者 Qianfeng WANG Yupeng LIU 《Frontiers of Earth Science》 SCIE CAS CSCD 2018年第2期408-419,共12页
原文传递
Spatiotemporal changes in vegetation coverage and its driving factors in the Three-River Headwaters Region during 2000-2011 被引量:48
17
作者 LIU Xianfeng ZHANG Jinshui +4 位作者 ZHU Xiufang PAN Yaozhong LIU Yanxu ZHANG Donghai LIN Zhihui 《Journal of Geographical Sciences》 SCIE CSCD 2014年第2期288-302,共15页
The Three-River Headwaters Region (TRHR), which is the source area of the Yangtze River, Yellow River, and Lancang River, is of key importance to the ecological secu- rity of China. Because of climate changes and hu... The Three-River Headwaters Region (TRHR), which is the source area of the Yangtze River, Yellow River, and Lancang River, is of key importance to the ecological secu- rity of China. Because of climate changes and human activities, ecological degradation oc- curred in this region. Therefore, "The nature reserve of Three-River Sou,'ce Regions" was established, and "The project of ecological protection and construction for the Three-River Headwaters Nature Reserve" was implemented by the Chinese government. This study, based on MODIS-NDVI and climate data, aims to analyze the spatiotemporal changes in vegetation coverage and its driving factors in the TRHR between 2000 and 2011, from three dimensions. Linear regression, Hurst index analysis, and partial correlation analysis were employed. The results showed the following: (1) In the past 12 years (2000-2011), the NDVI of the study area increased, with a linear tendency being 1.2%/10a, of which the Yangtze and Yellow River source regions presented an increasing trend, while the Lancang River source region showed a decreasing trend. (2) Vegetation coverage presented an obvious spatial difference in the TRHR, and the NDVI frequency was featured by a bimodal structure. (3) The area with improved vegetation coverage was larger than the degraded area, being 64.06% and 35.94%, respectively during the study period, and presented an increasing trend in the north and a decreasing trend in the south. (4) The reverse characteristics of vegetation cov- erage change are significant. In the future, degradation trends will be mainly found in the Yangtze River Basin and to the north of the Yellow River, while areas with improving trends are mainly distributed in the Lancang River Basin. (5) The response of vegetation coverage to precipitation and potential evapotranspiration has a time lag, while there is no such lag in the case of temperature. (6) The increased vegetation coverage is mainly attributed to the warm-wet climate change and the implementation of the ecological protection project. 展开更多
关键词 vegetation coverage spatiotemporal change future trend influence factors Three-River HeadwatersRegion
原文传递
2000-2014年秦巴山区植被覆盖时空变化特征及其归因(英文) 被引量:20
18
作者 刘宪锋 朱秀芳 +3 位作者 潘耀忠 李双双 马钰琪 聂娟 《Journal of Geographical Sciences》 SCIE CSCD 2016年第1期45-58,共14页
Using the Moderate Resolution Imaging Spectroradiometer-normalized difference vegetation index(NDVI) dataset,we investigated the patterns of spatiotemporal variation in vegetation coverage and its associated driving f... Using the Moderate Resolution Imaging Spectroradiometer-normalized difference vegetation index(NDVI) dataset,we investigated the patterns of spatiotemporal variation in vegetation coverage and its associated driving forces in the Qinling-Daba(Qinba) Mountains in 2000–2014.The Sen and Mann–Kendall models and partial correlation analysis were used to analyze the data,followed by calculation of the Hurst index to analyze future trends in vegetation coverage.The results of the study showed that(1) NDVI of the study area exhibited a significant increase in 2000–2014(linear tendency,2.8%/10a).During this period,a stable increase was detected before 2010(linear tendency,4.32%/10a),followed by a sharp decline after 2010(linear tendency,–6.59%/10a).(2) Spatially,vegetation cover showed a "high in the middle and a low in the surroundings" pattern.High values of vegetation coverage were mainly found in the Qinba Mountains of Shaanxi Province.(3) The area with improved vegetation coverage was larger than the degraded area,being 81.32% and 18.68%,respectively,during the study period.Piecewise analysis revealed that 71.61% of the total study area showed a decreasing trend in vegetation coverage in 2010–2014.(4) Reverse characteristics of vegetation coverage change were stronger than the same characteristics on the Qinba Mountains.About 46.89% of the entire study area is predicted to decrease in the future,while 34.44% of the total area will follow a continuously increasing trend.(5) The change of vegetation coverage was mainly attributed to the deficit in precipitation.Moreover,vegetation coverage during La Nina years was higher than that during El Nino years.(6) Human activities can induce ambiguous effects on vegetation coverage: both positive effects(through implementation of ecological restoration projects) and negative effects(through urbanization) were observed. 展开更多
关键词 秦巴山区 植被动态 气候因子 中分辨率成像光谱仪 植被覆盖度 归一化植被指数 HURST指数 植被覆盖率
原文传递
农业干旱监测研究进展与展望(英文) 被引量:11
19
作者 刘宪锋 朱秀芳 +3 位作者 潘耀忠 李双双 刘焱序 马钰琪 《Journal of Geographical Sciences》 SCIE CSCD 2016年第6期750-767,共18页
In this paper, we compared the concept of agricultural drought and its relationship with other types of droughts and reviewed the progress of research on agricultural drought monitoring indices on the basis of station... In this paper, we compared the concept of agricultural drought and its relationship with other types of droughts and reviewed the progress of research on agricultural drought monitoring indices on the basis of station data and remote sensing. Applicability and limitations of different drought monitoring indices were also compared. Meanwhile, development history and the latest progress in agricultural drought monitoring were evaluated through statistics and document comparison, suggesting a transformation in agricultural drought monitoring from traditional single meteorological monitoring indices to meteorology and remote sensing-integrated monitoring indices. Finally, an analysis of current challenges in ag- ricultural drought monitoring revealed future research prospects for agricultural drought monitoring, such as investigating the mechanism underlying agricultural drought, identifying factors that influence agricultural drought, developing multi-spatiotemporal scales models for agricultural drought monitoring, coupling qualitative and quantitative agricultural drought evaluation models, and improving the application levels of remote sensing data in agricultural drought monitoring. 展开更多
关键词 agricultural drought drought monitoring research progress research prospect
原文传递
Carbon Sequestration in Two Alpine Soils on the Tibetan Plateau
20
作者 Yu-Qiang Tian Xing-Liang Xu +3 位作者 Ming-Hua Song Cai-Ping Zhou Qiong Gao Hua Ouyang 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2009年第9期900-905,共6页
Soil carbon sequestration was estimated in a conifer forest and an alpine meadow on the Tibetan Plateau using a carbon- 14 radioactive label provided by thermonuclear weapon tests (known as bomb-^14C). Soil organic ... Soil carbon sequestration was estimated in a conifer forest and an alpine meadow on the Tibetan Plateau using a carbon- 14 radioactive label provided by thermonuclear weapon tests (known as bomb-^14C). Soil organic matter was physically separated into light and heavy fractions. The concentration spike of bomb-^14C occurred at a soil depth of 4 cm in both the forest soil and the alpine meadow soil. Based on the depth of the bomb-^14C spike, the carbon sequestration rate was determined to be 38.5 g C/m^2 per year for the forest soil and 27.1 g C/m^2 per year for the alpine meadow soil. Considering that more than 60% of soil organic carbon (SOC) is stored in the heavy fraction and the large area of alpine forests and meadows on the Tibetan Plateau, these alpine ecosystems might partially contribute to "the missing carbon sink". 展开更多
关键词 alpine soils bomb carbon carbon sequestration soil organic carbon.
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部