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1.
Coral reefs in the Negril Marine Park (NMP), Jamaica, have been increasingly impacted by nutrient pollution and macroalgal blooms following decades of intensive development as a major tourist destination. A baseline survey of DIN and SRP concentrations, C:N:P and stable nitrogen isotope ratios (δ15N) of abundant reef macroalgae on shallow and deep reefs of the NMP in 1998 showed strong P-limitation and evidence of increasing sewage pollution. In 1999, a sewage collection and treatment project began divertin...  相似文献   

2.
Under the influence of various natural and human factors, the relationship between the ecosystem services provided for human beings by a karst ecosystem is becoming increasingly complex, profoundly limiting the effective and sustainable development of the social economy and ecosystem protection in karst areas. Taking Guizhou, China as an example, which includes both karst(including five different landforms) and non-karst area, the study explored and compared the tradeoff and synergy between ecosystem services in both terrain types. The results showed higher change rates of water yield and soil retention in karst areas than those in non-karst areas, with only small differences in the carbon storage and crop production change. The ecosystem service relationships in the karst area from 1995 to 2005 were consistent with the relationships in the non-karst area. However, differences were observed in most of these relationships from 2005 to 2015. The relationships between ecosystem services in different karst landforms from 1995 to 2005 remained the same, but there are differences found in the relationships of ecosystem services from 2005 to 2015. The trade-off and synergistic relationships between ecosystem services in the different landforms were closely related to the changes of climate and land use, particularly related to rainfall, rainfall erosivity, farmland, and forestland.  相似文献   

3.
利用我国城镇居民人均可支配收入与消费支出的面板数据(1991-2009),采用变系数模型、协整理论等时间序列分析方法对其消费行为进行实证检验,并建立了城镇居民的消费模型,分析了边际消费倾向和自发性消费。结果表明:可支配收入与其消费支出之间存在着长期均衡的关系;当期收入是影响居民消费的最直接、最重要的因素,并据此提出相应的一些政策建议。  相似文献   

4.
Port-city system is a complex and integral system, and it can be simulated by system dynamic method, which is used to be employed to solve nonlinear problems. Based on the causality of the every element in the port-city system, the authors analyzed the feedback relation and logical relation among the system variables and system structure. A system-dynamic flow chart and correlation equations were put forward with VENSIM software, the quantitative relation was described, and the model was debugged. The devel...  相似文献   

5.
Numerous published results have showr the importance of the Wcstern Pacific Warm Pool (WPWP)surface centroid movement in ENSO-(EI Nino/Southcrn Oscillation)rclated studies .Howcver,some rccent research conclusions make it necessary to clarify the differenccs of the currently exicing two types of WPWP surface centroid:the geometric centroid and the thermal (heat)centrold.This study analyzes the physical backgrounds of the two typcs of centroid and points out their differenccs.which suggest that different types of ccntroid may scrve different study purposes.This study also shows that the ‘geometric center’of WPWP.actually a close approximation to the mass ccntroid,is more related to the Nino-3 region sca surfacc temperaturc(SST)ancmaly and can also be regarded as an important indicator of ENSO events.  相似文献   

6.
从增强型水体指数分析遥感水体指数的创建   总被引:6,自引:0,他引:6  
本文对新近提出的增强型水体指数(EWI)进行了分析和讨论,分别用经过大气校正和未经大气校正的两种影像来对该指数作了验证,并与改进的归一化差值水体指数(MNDWI)进行比较。结果表明该指数在经过大气校正的影像中对水体的增强和提取效果不理想,许多水体影像特征不但未能得到增强,反而受到抑制而被漏提。显然,该指数在创建时忽略了大气因素的影响。另外,该指数在构建上重复选择近红外和中红外波段也是造成提取效果不理想的原因之一。因此,为了创建正确的水体指数,避免水体增强和提取结果的偶然性和不确定性,水体指数的创建必须用经过大气校正的影像进行验证,而构建指数的波段也要避免不合理的重复选择,这样才能使所创建的指数具有更广的适应性。  相似文献   

7.
文化对世界格局的塑造是无形却深远的。当前研究中鲜有基于地理空间视角、应用计量方法探索国家文化差异并刻画全球文化空间格局规律。为此,本研究构建了基于欧氏几何距离的文化亲疏程度测算方法,利用Hofstede国别文化属性数据测度了国家间文化亲疏程度分值;继而以此分值构建网络矩阵,分别应用社区探索算法和基于“子群内外关系”的凝聚子群分析方法识别出各国因文化亲疏差异而结成的若干文化集团,综合2种结果,命名全球文化圈类型并分析其空间格局。结果显示:(1)全球存在盎格鲁-撒克逊文化圈、北欧文化圈、大陆欧洲文化圈、拉丁文化圈、东正教文化圈、西非-加勒比文化圈、伊斯兰教文化圈、泛亚文化圈8个文化圈,其中盎格鲁-撒克逊文化圈、北欧文化圈、大陆欧洲文化圈、拉丁文化圈关联较为紧密,组成泛欧美大文化圈;(2)中国与其他国家文化亲疏度存在一定程度上的由近及远分布特征:周边亚洲国家与中国最为亲密,少数高加索、巴尔干半岛和撒哈拉以南非洲国家也与中国较为亲密;亲疏不明显的国家广泛分布在中间地带,包括西亚、北非、中东欧,以及撒哈拉以南非洲和南美洲少数国家;较为疏远的国家主要分布在北欧、西欧、北美、大洋洲地区,在撒哈拉以南...  相似文献   

8.
This study examined the temporal trends of runoff and sediment load and their differential response to human activities in the Lishui river,a tributary of the Yangtze river in southern China.The long-term observation data at four gauging stations,generally involving two periods from 1954 to 1985 and from 2007 to 2011,were used.We detected no significant temporal trend for both the annual runoff volume(Q) and the annual suspended Sediment Load(SL) over more than 30 years before 1985.The flow duration curves and the Suspended Sediment Concentration(SSC) also hold constant before 1985.Compared with the period before 1985,SL has decreased by about 80% though Q remains unchanged for the period after 2007.Detailed examination shows that the flow duration curves after 2007 have changed with a significant decrease in the high-flow component,which acts as a major cause for the decreasing SL.In addition,SSC has decreased by several times,which also contributes to the decrease in SL after 2007.Both decreases in high-flow discharges and in SSC can be linked with recent human activities,mainly including vegetation establishment and dam constructions.The constant Q and the decreasing SL are also reported for the main stream of the Yangtze River and other major rivers in southern China,although they are orders of magnitude larger than our study area in drainage area size.The present study highlights the importance of high-flow discharges on SL and suggests that the use of SL is more appropriate to reflect environmental change than Q.  相似文献   

9.
Li  Kaizhi  Ke  Zhixin  Tan  Yehui 《中国海洋湖沼学报》2018,36(5):1671-1680
Journal of Oceanology and Limnology - Relatively few studies have investigated the community structure of zooplankton in the atolls of the central South China Sea. Zooplankton were sampled at nine...  相似文献   

10.
目前广泛应用的数字高程模型(DEM)包括SRTM和ASTER GDEM,但在地形影响下,两类数据的误差分布并不均匀。本文选用1:5万地形图DEM及河流要素作为参照,在青藏高原东麓山区开展实验,分别采用"河流-河谷"位置偏移量与高程中误差来评价两类数据的平面精度与垂直精度,结果表明:(1)实验区内SRTM3存在向西南方向的水平位置偏移,平均偏移量为127.8 m,ASTER GDEM则以正西方向偏移为主,平均偏移量为104.1 m,该区域ASTER GDEM的总体平面精度较好;(2)SRTM3数据样本的绝对误差分布相对集中,高程中误差为35.3 m,小于ASTER GDEM样本的高程中误差50.2 m,总体垂直精度优于ASTER GDEM;(3)在平均高程大于4500 m的高海拔区域,两类数据的中误差与高程值正相关,SRTM3中误差随高程增速较慢,垂直精度较ASTER GDEM高;(4)两组数据垂直精度对坡度有较大依赖性,中误差随坡度近似指数曲线增长,在平缓区域SRTM3中误差小于ASTER GDEM。本研究为该类数据在山区的选用及误差修正提供依据。  相似文献   

11.
以芦山MS7.0地震的地震波记录为例,比较分析我国12个地震台的同址gPhone重力仪与CTS-1地震计记录的地震波信号的频谱特征。观测结果表明,震中距大于2 000 km时,两种仪器记录的P波波形基本一致,只在幅度上稍有区别。P波的频谱分析结果表明,震中距较小时gPhone重力仪会遗失一些高频信号,震中距大于2 000 km时,两种仪器记录的P波优势频带均为0~0.3 Hz。  相似文献   

12.
Rainfall resource is very important to the development of society and economy,especially to eastern Jianghuai watershed which is now facing serious challenge of water shortage.Based on the observational records covering the period from 1957 to 1999,the characteristics of precipitation changing over eastern JiangHuai watershed and its connection to sediment discharge in Chibe River valley were studied using tendency analysis and correlation analysis.Results show that the rainfall in this area had a declining tendency in Spring at a rate of -21.2mm/10a,annual and Summer precipitation was increasing at the rate of 10.6mm/10a and 14.8mm/10a.The gray correlation analysis shows that sediment discharge correlated most closely with runoffs and the frequency of the rainstorm with a daily precipitation of 50-100mm,on the second place,with the number of rainy days.In addition,the paper suggests the major countermeasures and methods for controlling of soil and water losses in this area.  相似文献   

13.
用五点法进行抽样调查并探讨了湿地松粉蚧(Oracella acuta Lobdell)侵入后,湿地松(Pinuselliotii)新植树皮化学成分与粉蚧为害的关系。结果表明:均衡、协调的营养对粉蚧生长和繁殖有利;粉蚧为害主要导致新梢树皮蛋白质、粗灰分含量明显增加,还原糖含量明显减少;粉蚧发生高峰期,新梢树皮蛋白质含量与与粉蚧虫口密度呈显著正相关。  相似文献   

14.
本文在深入分析巴什布拉克铀矿区油气还原蚀变岩石的光谱特征,ASTER与ETM数据对蚀变岩石光谱特征反映的差异性的基础上,提出了正反两种蚀变信息提取的思路和两种数据在不同思路下提取蚀变信息的效果对比。研究表明,利用ASTER数据与ETM数据在增强研究区三价铁信息,间接反映油气还原蚀变规律方面效果相当;而在直接增强油气还原蚀变信息方面,ASTER数据的应用效果明显好于ETM数据。增强的遥感油气还原蚀变信息对分析研究区白垩系油气还原蚀变规律和矿区外围铀矿找矿具有重要的意义。  相似文献   

15.
Large-scale land consolidation projects(LCPs) have been carried out on the Loess Plateau to increase the area of agriculture land. The newly created land is prone to soil erosion under the effects of water and gravity. Taking a typical high-filling body(HFB) formed by LCPs in Yan’an, China as the subject, this study comprehensively investigated the types and causes of soil erosion with multiple methods of field investigation, on-site monitoring and laboratory tests. Results showed that the HFB p...  相似文献   

16.
走向海外是解决我国能源安全问题的必由之路。但海外油气藏评价往往缺乏第一手岩心资料, 使得储层孔隙结构和渗流规律认识不清, 影响评价效果。以海外J油田孔隙型碳酸盐岩油藏为例, 应用数字岩心技术开展油气藏孔渗特征研究。①以不同流动单元的铸体薄片图像作为输入数据, 经过中值滤波和阈值分割预处理后, 基于马尔科夫链蒙特卡洛数值重构算法构建数字岩心; ②分析孔喉分布、孔喉连通性、孔隙度特征; ③基于格子玻尔兹曼模拟方法开展单相和油水两相流动模拟, 计算数字岩心的绝对渗透率和相对渗透率曲线。结果表明, 构建的三维数字岩心能够刻画不同流动单元孔隙型碳酸盐岩的孔喉半径分布及孔喉连通程度的差异化特征。数字岩心孔隙度与铸体薄片孔隙度吻合度高, 数字岩心渗透率与真实岩心渗透率存在较好的正相关关系, 且符合真实岩心所属的流动单元。油水两相稳态流动模拟计算的相对渗透率曲线体现了不同流动单元的两相渗流能力差异, 可作为数值模拟输入条件, 以及估算油藏采收率。数字岩心分析与物理实验结果吻合良好, 证明了该方法的可靠性。为岩心资料稀缺条件下油气藏表征和渗流特征分析提供新的思路, 对油气藏精细描述具有重要的参考价值。   相似文献   

17.
The distributions of two ubiquitous fouling cheilostome bryozoans,Cryptosula pallasiana(Moll,1803)and W atersipora sp.,on a ship moored for almost six years in Qingdao Bay show diff erences with respect to illumination,C ryptosula being dominant on the side of the ship which was exposed to the sun and Watersipora dominating on the other side which was in shadow for most of the time.Competitive interactions for substrate space were nearly always won by Watersipora,which succeeded in overgrowing the edges of C ryptosula colonies regardless of the side of the ship.Reasons for the superiority of W atersipora in spatial competition with Cryptosula could include faster growth rate and the stronger feeding currents created by the larger lophophores of Watersipora.  相似文献   

18.
In this paper, remote sensing techniques,as well as field studies, have been used to investigate the geomorphological processes and landscape evolution along the Saravan Fault, SE Iran to highlight how topographic features were influenced by active tectonics. Quantitative geomorphic analysis was carried out using mountain-front sinuosity(Smf),valley floor width-valley height ratio(Vf), drainage basin asymmetry factor(Af), Hypsometric integral(Hi), drainage basin shape index(Bs), mean axial slope of channel(MASC), standard deviation of topography(STD) and index of active tectonic(Iat).Remote sensing techniques, as well as field studies revealed that the Saravan Fault have three parts trending N-S, NW-SE, and E-W. Obtained results show that basins with high Iat index are located at where the strike of the Saravan Faults changes and where several strike-slip faults are crossed the Saravan fault.  相似文献   

19.
Results of long-term explorations in the Kongqueting region, located in an East China Sea depression, suggest that the strong fault activity during the sedimentary period of the Pinghu formation significantly influenced the development of the sedimentary system. However, the aggregation and enrichment of the sand body under a tectonic background has become a problem that requires an immediate solution. Considering research outcomes of previous studies, this study used three-dimensional seismic and logging data to identify Y-or H-type and the en echelon distribution patterns of the fault plane, as well as identify the locations wherein the fault growth index value is greater than 1 in the study region, indicating the tectonic background of the fault transfer zone in the region. Second, the development type of the fault transfer zone was studied, and the sand body enrichment site was identified based on seismic inversion data and the development position of the fault transfer point. This helps clarify the evolution of sedimentary facies of the Pinghu formation combined with the sedimentary environment of the braided-river delta. Finally, after summarizing the coupling relationship between the synsedimentary fault systems and the sand body enrichment patterns, three sand-control models were determined, namely, the flexural-parallel, the en echelon collinear, and the torsional-reformed superimposed transfer zones. The findings of this study lay a foundation for the subsequent search of tectonic lithologic oil and gas reservoirs.  相似文献   

20.
随着服务业的发展和文化产业的不断推进,城市文化娱乐休闲服务业成为城市经济和社会发展的重要标志和推动力。本文以地理空间实体数据和商业统计数据为基础,以GIS 的空间数据可视化和统计分析方法,研究典型城市娱乐休闲服务业KTV在中国大陆地区的行业发展、空间分布及空间扩散特征。研究表明,KTV在全国发展迅速、分布广泛,在宏、中、微观的全国、省域和市域尺度下,其空间分布分别表现出空间区域分异、等级差异、面状均衡和中心集聚等特征,并与区域经济、人口、文化等因素有一定的相关性。各种类型KTV在空间扩散上具有由东向西,由中心向周边扩散的特点,其中连锁类KTV扩散具有社会经济现象地理扩散规律,主要表现为空间等级扩散和接触扩散特征。  相似文献   

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