城镇地籍基础地理数据建库方法探讨     

蔡素真 《福建地质》2011,30(1):67-73

通过对第二次全国土地调查城镇地籍调查数据建库标准的分析,提出一套基于大比例尺城镇地形图开展基础地理数据建库的方法,探讨利用数据建库成果地形图图式的符号化回放,既满足城镇地形图的出图效果又满足基础地理数据GIS方法管理的需求.  相似文献   

内蒙古二连盆地西南部第四纪沉积物中粘土矿物特征与古气候指示意义     

张磊  何付兵  蔡向民  周志广  徐吉祥  程新彬 《第四纪研究》2011,31(5):780-790

通过对内蒙古二连盆地西南部第四纪地层剖面进行系统测制,结合古生物化石建立起该区第四纪以来相对完整的地层层序,并对剖面上所采集的粘土矿物样品进行X射线衍射分析,以及根据样品中的粘上矿物成分、质量分数对本区古气候演化进行探讨.结果表明:研究区早更新世-晚更新世中期沉积物中,大量出现高质量分数的伊蒙混层和蒙脱石,反映季节性冷...  相似文献   

Optical characterization of CDOM in a marsh-influenced environment in the Changjiang (Yangtze River) Estuary   总被引：1，自引：1，他引：0  

Lei Gao  Daidu Fan  Chengxing Sun  Daoji Li  Jingong Cai 《Environmental Earth Sciences》2011,64(3):643-658

To elucidate the influence of tidal marshes on the amount and chemical structure of chromophoric dissolved organic matter (CDOM) in adjacent coastal waters, surface water samples were collected along three cross-marsh transects in tidal marshes within the Changjiang Estuary. In addition, three sediment cores were collected from the marshes and incubated for 10 h in the laboratory after adding overlying tidal waters. Nutrients, DOC, absorption, fluorescence excitation–emission matrix (EEM) spectroscopy, and other parameters were measured in these samples, which clearly illustrated releases by the tidal marshes of DOC, and CDOM absorbent and fluorescent molecules. To characterize the chemical nature of the marsh-derived CDOM, variations in a suite of optical indices (including molar absorptivity, absorption spectral slope, fluorescence quantum yield, and fluorescence ratios between certain excitation/emission locations) in these samples were plotted against the offshore distance of the stations as well as the incubation time. From the literature, it has been suggested that these variations are closely associated with molecular weight, aromaticity, and humic/fulvic or allochthonous/autochthonous ratios in the CDOM mixtures. This study showed that the CDOM fluorophores changed to more humic-like and were less protein-like from sea to land across the marsh gradients. Furthermore, subtractions between EEM spectra before and after laboratory incubations were applied to illustrate in greater detail the properties of the pure fluorescent compounds exchanged at the sediment–overlying water interface.  相似文献   

Assessing vegetation dynamics and their relationships with climatic variability in Heilongjiang province, northeast China   总被引：2，自引：1，他引：1  

Wenbin Liu  Tijiu Cai  Cunyong Ju  Guobin Fu  Yuefeng Yao  Xueqing Cui 《Environmental Earth Sciences》2011,64(8):2013-2024

In this study, the vegetation dynamics in Heilongjiang province and their relationships with climate variability were assessed using normalized difference vegetation index (NDVI) and meteorological datasets from 1981 to 2003. The conclusions from our results are as follows: (1) After 1981, vegetation cover, as indicated by the NDVI, exhibited an insignificant increasing tendency. However, the inter-annual variations of the NDVI showed apparent spatial differentiations. (2) The inter-annual changes of the NDVI were different from season to season. The spring and autumn NDVI values increased, while the summer and winter NDVI decreased. (3) The annual NDVI was significantly correlated with precipitation. Thus, as compared to temperature, precipitation was the dominant climatic factor affecting the vegetation dynamics in Heilongjiang province. (4) The trend in the NDVI showed a marked homogeneity corresponding to regional and seasonal variations in climate. Additionally, land use changes also play an important role in influencing the NDVI trends over some regions. All of these findings will enrich our knowledge of the natural forces that impact the stability of boreal ecosystems and provide a scientific basis for the environmental management in Heilongjiang province in response to climate change and human activities.  相似文献   

注入速率对CO_2地质储存封存潜力的影响分析     

李采  张可霓  许雅琴  何庆成 《上海国土资源》2011,32(1):24-27,32

国内某著名煤炭企业计划实施每年10万吨的CO2地质储存（CCS）项目,拟选了5组地层做为目标储层。但所选封存层平均渗透率在0.15~0.6mD,平均孔隙度在2~6%,属于低渗低孔地层,如不进行人工压裂提高注入层渗透率,要实现预定存储目标尚有一些困难。笔者在研究中发现,除对目标层进行一定的水裂酸化处理提高地层渗透特性可以显著提高注入性和存储能力外,CO2注入速率的变化对地层的封存能力和注入性也有明显影响。运用TOUGH2-ECO2N软件分别模拟了无水裂及水裂情况下8种不同注入速率下这些目标存储层的压力变化及CO2封存状态比例及理论最大封存能力。模拟结果表明使用水裂酸化方法对储层进行处理后,不仅可以使注入总量达到项目要求,还可使系统理论最大储存能力提高55%;并且在灌注过程中采用变速灌注方式,可以有效控制系统压力积聚,对将来实际灌注压力控制具有重要意义。  相似文献   

Impact of coastal engineering constructions on the topographic and morphological evolution of Quanzhou Bay, Fujian, China     

Chengqiang WuFeng Cai  Guangtao ZhaoYongling Zheng  Huiquan Lu 《Ocean & Coastal Management》2011,54(7):544-555

A series of port constructions and large-scale reclamation projects have been extensively carried out in Quanzhou Bay to pursue social and economic benefits. These projects have changed the natural topographical and morphological evolution since 1970. In this research, from comparison of topographical and morphological characteristics of the study area in 2008, 1972 and 1934, the obvious differences between two evolution stages (1934-1972 and 1972-2008) were analyzed, and the impact of coastal engineering constructions on the evolution of topography and morphology was evaluated quantitatively. The results show that evolution before the 1970s was characterized as a stable whole with local erosion in the channel and slow aggradation of the shoal and that the morphology was dominated by natural processes, as there was little coastal engineering construction before 1970. Since the 1970s, because of a series of engineering projects such as those reclaiming land and constructing ports, the bay has been in a stage of continuous silting, characterized by the channel narrowing and shrinking and shoal silting and expanding, which may result in the abandonment of ports around the bay and endanger the salt field, aquaculture and other agriculture. Potential solutions for the management of the coastal zone of Quanzhou Bay and other similar bays by state and local agencies are suggested, such as calling for the attention of the state and local government, strengthening coastal zone management, scientific planning and reasonable exploitation, and in particular, changing the utilization of the sea area.  相似文献   

琼东南盆地陵水组层序格架及沉积体系的时空配置关系     

蔡佳  王华 《海洋地质译丛》2011,(1):16-21

利用层序地层学、沉积学原理和方法,对琼东南盆地古近系陵水组进行了层序划分和沉积体系时空配置关系的研究。建立了陵水组的层序地层格架,将其划分为Els3、ElS2和Elsl三个三级层序,其层序和体系域变化主要受控于凹陷内沉降中心的分布位置,沉积主要受控于盆地边缘的断坡带。每个三级层序低位体系域发育局限,海侵与高位体系域发育。沉积体系构成以扇三角洲、三角洲、滨海平原和浅海为主。探讨了沉积体系的演化,总结了其时空配置关系的特点。  相似文献   

Objective Determination of Crack Initiation Stress of Brittle Rocks Under Compression Using AE Measurement   总被引：1，自引：0，他引：1  

X. G. Zhao  M. Cai  J. Wang  P. F. Li  L. K. Ma 《Rock Mechanics and Rock Engineering》2015,48(6):2473-2484

  相似文献   

西藏改则洞错地区白垩纪火山岩锆石U-Pb年代学、Hf同位素组成及对班公-怒江洋俯冲闭合的制约   总被引：1，自引：0，他引：1       下载免费PDF全文

付佳俊  丁林  许强  蔡福龙  岳雅慧  郭钰 《地质科学》2015,50(1):182-202

班公湖—怒江缝合带是青藏高原内一条重要的缝合带,其俯冲极性和闭合时限一直存在着争议,这无疑限制了我们对青藏高原演化历史的认识。本文对仲岗安山玄武岩和一套新发现的晚白垩世安山岩进行研究,获得了其锆石U-Pb年龄分别为123.75±0.92 Ma和74.23±0.76 Ma。仲岗安山玄武岩锆石的ε_(Hf)(t)值为-7.3~+4.4,具有岛弧玄武岩特征,指示班公湖—怒江洋盆在该地区仍然继续向北俯冲;晚白垩世安山岩锆石的ε_(Hf)(t)值为+3.1~+11.1,其可能是亏损地幔混熔了部分的陆壳物质而形成的,且不整合在蛇绿岩之上。结合区域资料本文认为班公湖—怒江洋盆在改则地区的闭合时限在100~75 Ma之间。  相似文献   

全球海洋人为碳储量估算及时空分布研究进展     

Huang Peng  Chen Liqi  Cai Minggang 《地球科学进展》2015,30(8):952-959

海洋是全球最大的碳汇,确定海洋中人为碳含量及其时空变化是一件具有挑战性的工作。就当前海洋人为碳含量确定方法、人为碳储量及其随时间变化进行综述总结。研究表明海洋仍然可以吸收并储藏大量的人为碳,但未来对于海洋吸收储藏人为碳的研究仍具有诸多不确定性。已有证据表明稳态海洋的概念不完全正确,需要在非稳态条件下重新定义人为碳并开展研究。同时需要积累更多的观测数据,采用包括观测和模式模拟等手段来研究不同时间尺度的人为碳的吸收和储藏过程。  相似文献