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561.
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
562.
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
563.
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
564.
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
565.
In this paper, a new polychaete species, Eranno carrerai sp. nov. from coastal areas of China, is described based on specimens deposited in the Marine Biological Museum of the Chinese
Academy of Sciences, Qingdao, collected during 1957 to 1976 from the Yellow Sea, East China Sea and South China Sea at depths
of 9–210 m. 相似文献
566.
We estimated the reproductive success of adult brood fish and the heritability of growth-related traits for large yellow croaker (Larimichthys crocea). We created two independent full-factorial cross groups (1 and 2) by crossing 4 males×4 females and 4 males×3 females, respectively. We measured the body weight (BW), body length (BL), and body height (BH) of 281 individuals from group 1 and 318 individuals from group 2 at 20 months post hatch (harvest age). We also collected a tissue sample from each individual. The parents and offspring were genotyped using six polymorphic microsatellites. Of the 599 offspring, 99.2% were assigned to a single pair of parents. In both groups, some parent pairs produced a large number of offsprings while other pairs did not produce any offspring. The genetic diversity and putative Ne were lower in the offsprings than in the parents in both groups. The heritability estimates at 20-month age were 0.13±0.10 for BW, 0.19±0.13 for BL, and 0.09±0.06 for BH. The genetic and phenotype correlation between BW, BL, and BH was close to 1. The results provide basic information for selective breeding and further genetic characterization of large yellow croaker. 相似文献
567.
568.
土地利用变化对喀纳斯自然保护区生态系统服务价值的影响 总被引:2,自引:0,他引:2
应用喀纳斯自然保护区1980,2005年两个时期的LandsatTM影像解译数据,采用Costanza生态系统服务价值计算公式,参照中国单位面积生态服务价值系统,确定了喀纳斯自然保护区生态系统单位面积生态服务价值系数,分析了保护区土地利用变化对其生态系统服务价值的影响.结果表明,保护区林地面积在减少,草地,水域、建设用地面积有所增加;研究期内生态系统服务价值从26.79亿元减少到26.02亿元,天然有林地和高覆盖度草地的减少是生态服务价值降低的主要原因;保持土壤、维持生物多样性、气候调节等各单项功能服务价值均呈现不同程度的减少,说明保护区生态环境不断趋向恶化. 相似文献
569.
基于规划协调的乡镇土地利用统一分类研究 总被引:2,自引:0,他引:2
清晰统一的用地分类是实现乡镇土地利用总体规划和村镇体系规划协调的基础。回顾了建设和国土部门土地利用分类的历程,提出统一土地分类的原则,对《土地利用现状分类》(GB/T 21010—2007)和《镇规划标准》(GB 50188—2007)中土地分类进行对比分析,确定了统一的乡镇土地利用分类,为有效指导农村区域土地资源利用和规划提供借鉴。统一的乡镇土地利用分类包括12个一级类,59个二级类,其中有9个二级类划分了三级类,三级类共有21个;以《土地利用现状分类》(GB/T 21010—2007)为准的一级类包括8个,二级类包括49个;以《镇规划标准》(GB 50188—2007)为准的二级类1个;两者综合并重新定义的一级类4个,二级类9个。 相似文献
570.
为了研究西湖凹陷平北地区泥岩微量及稀土元素的分布特征及其地质意义,采用ICP—MS对研究区25个泥岩样品进行了稀土元素和微量元素分析,研究表明:(1)研究区泥岩稀土元素主要来自陆源碎屑矿物,源岩主要为沉积岩及碱性玄武岩;(2)始新世末构造运动揭示的构造沉积界线在研究区留下了证据,微量元素比值、稀土总量等参数在此界面上存在明显的突变,界线十分明显,并且此界线亦是研究区平湖组与花港组的沉积界面,界面以下以三角洲沉积为主,界面之上主要为河流相沉积,这一沉积相转换面在研究区P1井尤为明显;(3)利用Sr/Cu比值推测平北地区始新世中晚期.早渐新世经历了较为明显的气候变化,总体上有逐渐变温湿趋势,并且研究区北部要温湿于南部。 相似文献