中国区域可持续发展水平及其空间分特征   总被引：33，自引：3，他引：30  

廖志杰  刘岳 《地理学报》2000,55(2):139-150

区域ＰＲＥＤ系统是个非线性的复杂巨系统。在已建立的人口、环境与可持续发展数据库基础上,应用耗散结构理论建立区域ＰＲＥＤ系统的非线性数学模型,提出衡量区域ＰＲＥＤ系统可持续发展水平的指数（ＳＤＩ）的概念和计算方法,定量地表达了中国各省区的右持续发展状况,进而应用地图学和地理信息系统方法研究其空间分布特征,分析造成这种格局的原因并提出相应对策。  相似文献   

Measuring groundwater–surface water interaction and its effect on wetland stream benthic productivity, Trout Lake watershed, northern Wisconsin, USA     

Randall J. Hunt  Mac Strand  John F. Walker   《Journal of Hydrology》2006,320(3-4):370-384

Measurements of groundwater–surface water exchange at three wetland stream sites were related to patterns in benthic productivity as part of the US Geological Survey's Northern Temperate Lakes–Water, Energy and Biogeochemical Budgets (NTL–WEBB) project. The three sites included one high groundwater discharge (HGD) site, one weak groundwater discharge (WGD) site, and one groundwater recharge (GR) site. Large upward vertical gradients at the HGD site were associated with smallest variation in head below the stream and fewest gradient reversals between the stream and the groundwater beneath the stream, and the stream and the adjacent streambank. The WGD site had the highest number of gradient reversals reflecting the average condition being closest to zero vertical gradient. The duration of groundwater discharge events was related to the amount of discharge, where the HGD site had the longest strong-gradient durations for both horizontal and vertical groundwater flow. Strong groundwater discharge also controlled transient temperature and chemical hyporheic conditions by limiting the infiltration of surface water. Groundwater–surface water interactions were related to highly significant patterns in benthic invertebrate abundance, taxonomic richness, and periphyton respiration. The HGD site abundance was 35% greater than in the WGD site and 53% greater than the GR site; richness and periphyton respiration were also significantly greater (p≤0.001, 31 and 44%, respectively) in the HGD site than in the GR site. The WGD site had greater abundance (27%), richness (19%) and periphyton respiration (39%) than the GR site. This work suggests groundwater–surface water interactions can strongly influence benthic productivity, thus emphasizing the importance of quantitative hydrology for management of wetland-stream ecosystems in the northern temperate regions.  相似文献   

Macroinvertebrate assemblages in conditions of low-discharge streams of the Cerová vrchovina highland in Slovakia     

Zuzana Pastuchov 《Limnologica》2006,36(4):241-250

Macroinvertebrate communities at 16 sites in Cerová vrchovina highland were sampled in 2000–2001 to analyze the influence of environmental factors on community structure with emphasis on Ephemeroptera, Plecoptera and Trichoptera (EPT). The extreme hydrological conditions of this area determine the macroinvertebrate community structure. Totally, 16 Ephemeroptera, 8 Plecoptera and 36 Trichoptera taxa were found. Predators of the families Perlidae, Perlodidae and Chloroperlidae (Plecoptera) were absent. The record of Protonemura aestiva is the second one in Slovakia. Ephemeroptera were represented mainly by rheophilous taxa. A rare lowland species Baetis tracheatus was found, known previously just from West Slovakia. Trichoptera were mainly represented by submontane rheophilous taxa. Species preferring low currents or backwaters from the family Limnephilidae were also recorded. Altitude and dissolved oxygen content were found to be the most important environmental variables determining the EPT community structure. Six types of streams were distinguished by the results of multivariate analysis, taxonomic composition and metric values. They belong to two main types: (1) EPT communities of the natural streams and (2) EPT communities of disturbed streams, where two types of stressor were identified–organic pollution and low discharge. A similarity between EPT communities of organically polluted streams and streams with very low flow was discovered. Values of biotic indices decreased in summer. The most diversified communities were found in the spring during higher water levels and better oxygen conditions.  相似文献   

Introductory perspective on the COREF Project     

Yasufumi  Iryu  Hiroki  Matsuda  Hideaki  Machiyama  Werner E.  Piller  Terrence M.  Quinn  Maria  Mutti 《Island Arc》2006,15(4):393-406

Abstract Coral reefs are tropic to subtropic, coastal ecosystems comprising very diverse organisms. Late Quaternary reef deposits are fossil archives of environmental, tectonic and eustatic variations that can be used to reconstruct the paleoclimatic and paleoceanographic history of the tropic surface oceans. Reefs located at the latitudinal limits of coral‐reef ecosystems (i.e. those at coral‐reef fronts) are particularly sensitive to environmental changes – especially those associated with glacial–interglacial changes in climate and sealevel. We propose a land and ocean scientific drilling campaign in the Ryukyu Islands (the Ryukyus) in the northwestern Pacific Ocean to investigate the dynamic response of the corals and coral‐reef ecosystems in this region to Late Quaternary climate and sealevel change. Such a drilling campaign, which we call the COREF (coral‐reef front) Project, will allow the following three major questions to be evaluated: (i) What are the nature, magnitude and driving mechanisms of coral‐reef front migration in the Ryukyus? (ii) What is the ecosystem response of coral reefs in the Ryukyus to Quaternary climate changes? (iii) What is the role of coral reefs in the global carbon cycle? Subsidiary objectives include (i) the timing of coral‐reef initiation in the Ryukyus and its causes; (ii) the position of the Kuroshio current during glacial periods and its effects on coral‐reef formation; and (iii) early carbonate diagenetic responses as a function of compounded variations in climate, eustacy and depositional mineralogies (subtropic aragonitic to warm‐temperate calcitic). The geographic, climatic and oceanographic settings of the Ryukyu Islands provide an ideal natural laboratory to address each of these research questions.  相似文献   

2004年临汾市高温的气候特点和环流特征分析          下载免费PDF全文

孙悦  秦爱民  张临平  刘福新  李国强 《山西气象》2006,(2):22-23

本文从分析亚欧环流形势出发,对比历史资料平均情况,对造成2004年临汾市持续高温的500hPa高度场和850hPa的温度场的实况资料以及平流等物理量作了较详细的分析,找出了临汾市夏季出现高温的可能指标。  相似文献   

Integrated,Regional, Natural Resource and Environmental Planning and the Natural Heritage Trust Phase 2: a case study of the Northern Agricultural Catchments Council,Western Australia     

Megan Farrelly 《The Australian geographer》2007,38(3):309-333

Since 2002, the Australian Natural Heritage Trust Phase 2 (NHT2) has required community groups seeking funds for natural resource management projects to have developed nationally accredited regional strategies and investment plans. This case study reports on the progress of one such regional (and sub-regional) group, examining in particular the perceptions of the community group members and other stakeholders of the overall process. Through interviews, participant observation and document analysis in 2004–05, the process of developing a regional strategy and an investment plan by the Northern Agricultural Catchments Council in Western Australia, and the involvement of regional stakeholders in the process, were examined. While the concept of regional-scale management was perceived favourably by community interviewees, their concerns related to increasing bureaucracy, the need for further local involvement, more on-ground action instead of further planning, the relevance of the regional Council to local communities, and the motives of Council members. Communication with regional stakeholders was extensive in preparing the regional strategy, but fell short during the development of the investment plan. The success of the regional planning process will be evidenced by whether members of the regional community actively implement regional priorities, and whether long-term funding and support from the State and Australian governments are provided.  相似文献   

THE GRAVESTONE INDEX: TRACKING PERSONAL RELIGIOSITY ACROSS NATIONS,REGIONS, AND PERIODS*     

Wilbur Zelinsky 《Geographical review》2007,97(4):441-466

ABSTRACT. Given shortcomings in traditional methods of gauging levels of religious sentiment in national or local communities—affiliation with a congregation, church attendance, responses to opinion polls—this exploratory article proposes a novel, arguably more sensitive measure of personal religiosity, the Gravestone Index; that is, the incidence of religious symbols, iconography, or text on permanent memorials. Its application to 58,490 grave markers observed in 111 community, or nondenominational, cemeteries in the United States, Canada, and Great Britain yielded substantial findings, some expected but others violently at odds with the conventional wisdom. Seemingly reflecting the secularization of society, the Gravestone Index declines throughout the early twentieth century but, contrariwise, has rebounded strongly since the 1960s, indicating some sort of ongoing religious revival in all three lands. However, it fails to show any of the anticipated regional variation within the United States, notably that between South and non‐South. Even more surprisingly, it records a level of British and Canadian religiosity persistently far above the U.S. value.  相似文献   

A 6000-year record of ecological and hydrological changes from Laguna de la Leche, north coastal Cuba     

Matthew C. Peros  Eduard G. Reinhardt 《Quaternary Research》2007,67(1):69-82

Laguna de la Leche, north coastal Cuba, is a shallow (≤ 3 m), oligohaline (∼ 2.0-4.5‰) coastal lake surrounded by mangroves and cattail stands. A 227-cm core was studied using loss-on-ignition, pollen, calcareous microfossils, and plant macrofossils. From ∼6200 to ∼ 4800 cal yr BP, the area was an oligohaline lake. The period from ∼ 4800 to ∼ 4200 cal yr BP saw higher water levels and a freshened system; these changes are indicated by an increase in the regional pollen rain, as well as by the presence of charophyte oogonia and an increase in freshwater gastropods (Hydrobiidae). By ∼ 4000 cal yr BP, an open mesohaline lagoon had formed; an increase in salt-tolerant foraminifers suggests that water level increase was driven by relative sea level rise. The initiation of Laguna de la Leche correlates with a shift to wetter conditions as indicated in pollen records from the southeastern United States (e.g., Lake Tulane). This synchronicity suggests that sea level rise caused middle Holocene environmental change region-wide. Two other cores sampled from mangrove swamps in the vicinity of Laguna de la Leche indicate that a major expansion of mangroves was underway by ∼ 1700 cal yr BP.  相似文献   

基于快照-增量的时空索引机制研究   总被引：8，自引：0，他引：8  

尹章才  李霖 《测绘学报》2005,34(3):257-261,282

已有的时空索引是基于时间或空间索引的扩展,将相应的空间或时间成分作为属性,难以同时顾及时间查询和空间查询的效率.分析基于版本-增量的时空数据模型,提出基于快照-增量的时空数据索引机制.该索引将时间和空间作为同等重要的维,满足时空联合查询的效率.  相似文献   

Simulation of groundwater flow and environmental effects resulting from pumping   总被引：1，自引：1，他引：1  

Nguyen Cao Don  Hiroyuki Araki  Hiroyuki Yamanishi  Kenichi Koga 《Environmental Geology》2005,47(3):361-374

In coastal lowland plains, increased water demand on a limited water resource has resulted in declining groundwater levels, land subsidence and saltwater encroachment. In southwestern Kyushu, Japan, a sinking of the land surface due to over pumping of groundwater has long been recognized as a problem in the Shiroishi lowland plain. In this paper, an integrated model was established for the Shiroishi site using the modular finite difference groundwater flow model, MODFLOW, by McDonald and Harbaugh (1988) and the modular three-dimensional finite difference groundwater solute transport model, MT3D, by Zheng (1990) to simulate groundwater flow hydraulics, land subsidence, and solute transport in the alluvial lowland plain. Firstly, problems associated with these groundwater resources were discussed and then the established model was applied. The simulated results show that subsidence rapidly occurs throughout the area with the central prone in the center part of the plain. Moreover, seawater intrusion would be expected along the coast if the current rates of groundwater exploitation continue. Sensitivity analysis indicates that certain hydrogeologic parameters such as an inelastic storage coefficient of soil layers significantly contribute effects to both the rate and magnitude of consolidation. Monitoring the present salinization process is useful in determining possible threats to fresh groundwater supplies in the near future. In addition, the integrated numerical model is capable of simulating the regional trend of potentiometric levels, land subsidence and salt concentration. The study also suggests that during years of reduced surface-water availability, reduction of demand, increase in irrigation efficiency and the utilization of water exported from nearby basins are thought to be necessary for future development of the region to alleviate the effects due to pumping.  相似文献