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1.
APPLICATION OF ANALYTIC HIERARCHY PROCESS TO ASSESSING THE ECOLOGICAL VULNERABILITY OF WETLANDS IN THE JIANGHAN PLAIN 总被引：5，自引：1，他引：4
WANGXue-lei NINGLong-mei HUWang-bin 《中国地理科学(英文版)》2003,13(3):272-276
Wetlands in the Jianghan Plain are important components of wetland types in lake area in the middle and lower reaches the Changjiang (Yangtze) River and they fulfill many uses and functions related to hydrology,waste assimilation, ecosystem productivity and biodiversity. Owing to natural factors and human activities, especially excessive reclamation from lakes, the shrinking process of the lakes has been accelerated. Wetland ecosystem has shown the characteristics of vulnerability. According to the analysis of wetland ecological function in the Jianghan Plain, this paper presented an index system related to productivity, stability and environmental capacity. By using the method of Analytic Hierarchy Process, we computed the values of the relative weights of the indexes, and evaluated the vulnerability level of the wetland ecosystem by the method of multi-indexes. The case study showed that the fragile extent of wetland ecosystem in the Jianghan Plain is 5.6. This means that the wetland ecosystem in the Jiang-han Plain is laid to the state of middle vulnerability. Therefore, the wetland conservation and eco-rehabilitation in the JiangJaan Plain should be paid attention to. 相似文献
2.
《中国海洋湖沼学报》1985,(2)
The motions of diurnal, semidiurnal, and shallow-water tides and tidal currents in the Bohai Sea are computed using a finite-difference method based on two-dimensional tidal wave equations. Good agreement of the computed results with the observed data is achieved for diurnal and semidiurnal tides. The general pattern of the computed quarterdiurnal tide conforms to the observed pattern, but the computed amplitudes are on the high side. This is attributed to the ineligibility of the friction terms in the two-dimensional governing equations to dissipate the energy of high frequency tidal waves. It is found that the existing semidiurnal cotidal charts have considerable differences in Laizhou Bay. The difference is likely caused by the movement of the coastline of the Yellow River Delta. The present result coincides with the recent empirical cotidal chart. The computation shows a new current-amphidromic point for both semidiurnal and diurnal tidal currents. The diurnal current has two current-amphidromic poi 相似文献
3.
1 INTRODUCTION The Changjiang (Yangtze) Delta and its neighboring regions mentioned in this article is located in the lower reaches of the Changjiang River, whose north, east, south and west adjacent places are Xingtongyang Canal, Huanghai Sea, East China Sea, Qiantang River, Hangzhou Bay and Nanjing, Zhenjiang respectively. These regions belong to Jiangsu Province, Zhejiang Province and Shanghai City in administrative division, being one of the economic developed regions. The … 相似文献
4.
《中国海洋湖沼学报》1985,(1)
In this paper, the sea-air heat exchange over the Kuroshio in the East China Sea during the winters of 1954-1972 is computed and analysed. The results indicate that the year to year anomalies of sea-air heat exchange are obvious and the values are mainly controlled by the intensity of the cold air at the same time. The authors have found a close relationship between sea-air heat exchange and precipitation in the region of the Changjiang River during the early summer. Finally, the predicting indication for forecasting this precipitation around the middle and lower reaches of Changjiang River in June is given. 相似文献
5.
余泽忠 《中国地理科学(英文版)》1991,1(3):248-261
The building of Shuikou Hydropower Station in the Minjiang River is the largest one in the region of east China. Its install capacity is 1.4 million kw., and its generated energy of planning is 4.95 billion kwh each year. In accordance with a comprehensive survey of the valley of the middle-lower reaches of the Minjiang River and the characteristic of hydrography and in association with the specific type of the hydrography station, we can be sure that no harm will be done to the ecological environment when a hydropower station is built at Shuikou. Not only the deposition of silt within the reservoir must not be very serious, it is also more favorable than before for the irrigation of farmland on plains in the lower reaches of the Minjiang River and inland navigation.In addition, after the completion of the power station, the ecological environment will be the same as before both at the Minjiang River estuary and beyond it. 相似文献
6.
SEAWATER INTRUSION TYPES AND REGIONAL DIVISIONS IN THE SOUTHERN COAST OF LAIZHOU BAY 总被引：1，自引：0，他引：1
The southern coast of Laizhou Bay, Bohai Sea, is one of the areas in China most seriously impacted by seawater intrusion. Based on the sources of intruding waterbedies, seawater intrusion can be divided into two types: intrusion of saline water derived from modern seawater, and intrusion of subsurface brine and saline water derived from paleo-seawater in shallow Quaternary sediments. There are some distinct differences in their formation, mechanism and damage. The subsurface brine intrusion is a special type, which can cause very serious disaster. The coastal landform and the Quaternary hydrogeological environment are predominant factors in the classification of seawater intrusion types. Various coastal environments in different coastal sections result in three types of intrusion: seawater intrusion, saline groundwater intrusion, and mixed seawater and saline water intrusion, in the southern coast of Laizhou Bay, which can be divided into four areas: the sea-water intrusion area in the northern Laizhou City coast, the mixed seawater and saline groundwater intrusion area in the Baisha River-Jiaolai River mouth plain area, the mixed seawater and saline groundwater intrusion area in the Weihe River mouth plain area northern Changyi county coast, and the saline ground-water intrusion area in the northern Shouguang plains. 相似文献
7.
程其畴 《中国地理科学(英文版)》1992,2(1):74-79
The Green Corridor in the lower reaches of the Tarim River is not only a unique natural landscape in desert but also an important passageway. Nowadays, the ecologic environment of the corridor is getting worse and worse due to man's economic activities and the lack of knowledge of the importance of the environment, which is one of is the three environment problems in Xinjiang. The corridor is in great need of planning and managing. 相似文献
8.
Strom surges are not only determined by the atmospheric forcing,but also influenced by the coastal geometry and bathymetry.The Bohai Sea,as one of China’s marginal seas,is seriously harmed by storm surges,especially those caused by cold-air outbreaks.As the coastline of the Bohai Sea has changed evidently these years,storm surges may have new characteristics due to the changes in the local geometry.This paper aims to find out these new characteristics by primarily investigating the influence of the changes in the local geometry on storm surges with numerical methods.20 scenarios were constructed based on the track and inten-sity of the cold-air outbreaks to describe the actual situation.By analyzing the model results of the control scenarios,it is found that the main changes of the maximum surge elevation occur in the Bohai Bay and the Laizhou Bay.At the top of the Bohai Bay,the maximum surge elevation is obviously decreased,while in the Laizhou Bay,it is enhanced by the growing Yellow River Delta.This,however,does not suggest that the storm surges in the Laizhou Bay become more serious.A comparison of the risk assessment of storm surges in the Tanggu,Huanghua and Yangjiaogou regions shows that the risk of storm surges in these coastal areas is lightened by the evolvement of the coastal geometry.Particularly near Yangjiaogou,though the maximum surge elevation becomes higher to subject more areas to risk,the risk is still reduced by the evolvement of the Yellow River Delta. 相似文献
9.
陈海龙 《中国地理科学(英文版)》1992,2(2):145-158
According to historical records, there are 264 drought and flood years, occurred in the upper and middle reaches of the Changjiang (Yangtze) River during last 1020 years from 961 to 1980. The evolutionary law and developing trend of drought and flood years are studied. The distribution of drought and flood years are non-uniform and the dry and flood seasons in a year are concentrated. At the angle of monsoon circulation, at present the climate in the upper and middle reaches of the Changjiang River is just in the late stage of frequent drought period and the early stage of least flood period. In addition, the cycle of drought and flood and the feature of drought and flood occurred in the upper, middle and lower reaches of the Changjiang River are analyzed. It shows that the short period less than 10 years is in the majority, and the drought and flood occurred most frequently in the middle and lower reaches of the Changjiang River. 相似文献
10.
《青岛海洋大学学报(英文版)》2014,(1):23-31
A three-dimensional ecosystem model, using a PIC （Particle-In-Cell） method, is developed to reproduce the annual cycleand seasonal variation of nutrients and phytoplankton biomass in Laizhou Bay. Eight state variables, i.e., DIN （dissolved inorganicnitrogen）, phosphate, DON （dissolved organic nitrogen）, DOP （dissolved organic phosphorus）, COD （chemical oxygen demand）,chlorophyll-a （Chl-a）, detritus and the zooplankton biomass, are included in the model. The model successfully reproduces the ob-served temporal and spatial variations of nutrients and Chl-a biomass distributions in the bay. The nutrient concentrations are at highlevel in winter and at low level in summer. Double-peak structure of the phytoplankton （PPT） biomass exists in Laizhou Bay, corre-sponding to a spring and an autumn bloom respectively. Several numerical experiments are carried out to examine the nutrient limita-tion, and the importance of the discharges of the Yellow River and Xiaoqinghe River. Both DIN limitation and phosphate limitationexist in some areas of the bay, with the former being more significant than the latter. The Yellow River and Xiaoqinghe River are themain pollution sources of nutrients in Laizhou Bay. During the flood season, the algal growth is inhibited in the bay with the YellowRiver discharges being excluded in the experiment, while in spring, the algal growth is enhanced with the Xiaoqinghe River ex-cluded. 相似文献
11.
Based on the new data of the Quaternary along the coast of Hainan Island, China, this paper puts forward that the Holocene in Hainan Island can be divided into four formations: Wanning formation (Q41), Sanya formation (Q42-1), Qiongshan formation (Q42-2) and Ledong formation (Q43). Spore-pollen analysis shows that there are 6 spore-pollen zones existed, reflecting two cycles of climatic fluctuation from warm-dry to hot-humid. The climax of hot-humid period occurred 6,000-5,000 years B.P.. Based on the 14C dating data of the 38 samples representing the positions of ancient sea level, a breakthrough curve representing the sea level change during the Holocone is obtained, in which , a sea level change caused by tectonic movement is subtracted. Two cycles of rise-drop of sea level with three periods of high sea level were found. The period with the highest sea level is some 6,000-5,000 years B.P.. According to the rise-drop rate of sea level, four periods of the sea level change can be distinguished in the 相似文献
12.
黄河是中华民族的母亲河,而京杭大运河则担负着河运的重要职责,其重要性决定了古代关于黄运工程及其治理的地图数量繁多。本文旨在通过对大量明、清时期黄河、京杭大运河水利地图的梳理,对明、清时期水利地图的载体形式、表现形式和绘制特点进行剖析,并探讨其在地理学、地图学、水利学方面的应用价值和研究价值。明、清时期的黄河、京杭大运河地图,从载体形式来分,主要分为水利典籍（志书、图说）附图和绘本舆图2类：前者多为示意性地图,画法比较简单,只起到辅助说明水利典籍的作用;后者多采用山水形象画法绘制,多为长卷展开景物再现式地图,其主要特点是形象直观。其采用的“对景法”地图表现形式（即所绘黄河、京杭大运河两岸各类地物要素均朝向河流中心线）,容易引起读者的视觉共鸣,轻松构筑被描画事物的整体画面。从表现形式和绘制特点来看,明、清时期还出现了另外2类地图：计里画方类地图和经纬度实测地图,但由于其实用性和艺术性不如山水形象画法地图,因此,这2类地图在明、清并没有得到广泛普及。但从功能和价值而言,不论是长卷展开式古地图、计里画方类古地图,还是经纬度实测地图,对于古地图史、历史地理学、古代水利研究,对如今的地图、水利、地理学研究等,都是不可多得的历史瑰宝。 相似文献
13.
天水谢家湾全新世环境变迁及人地关系演化 总被引：2，自引：1，他引：1
在野外详细观测的基础上，对天水谢家湾全新世黄土剖面以2cm为间距进行了连续采样，并对所有样品作了磁化率和粒度分析，结果综合反映出研究区自全新世以来，经历了早期升温、中期基本暖湿、晚期趋于干冷的气候环境演化阶段，其中全新世中期在总体温湿的大背景下，存在频繁的气候波动。以此为基础，结合对渭河文化的历史研究资料，探讨了区内约1万年以来的人地关系演化历史，指出人地关系的和谐与统一，对人类社会发展具有重要意义。 相似文献
14.
Sedimentary evolution of the Holocene subaqueous clinoform off the southern Shandong Peninsula in the Western South Yellow Sea 总被引：1，自引：0，他引：1
Jiandong Qiu Jian Liu Yoshiki Saito Zigeng Yang Baojing Yue Hong Wang Xianghuai Kong 《中国海洋大学学报(英文版)》2014,13(5):747-760
Based on the stratigraphic sequence formed since the last glaciation and revealed by 3000 km long high-resolution shallow seismic profiles and the core QDZ03 acquired recently off the southern Shandong Peninsula, we addressed the sedimentary characteristics of a Holocene subaqueous clinoform in this paper. Integrated analyses were made on the core QDZ03, including sedimentary facies, sediment grain sizes, clay minerals, geochemistry, micro paleontology, and AMS 14 C dating. The result indicates that there exists a Holocene subaqueous clinoform, whose bottom boundary generally lies at 15–40 m below the present sea level with its depth contours roughly parallel to the coast and getting deeper seawards. The maximum thickness of the clinoform is up to 22.5 m on the coast side, and the thickness contours generally spread in a banded way along the coastline and becomes thinner towards the sea. At the mouths of some bays along the coast, the clinoform stretches in the shape of a fan and its thickness is evidently larger than that of the surrounding sediments. This clinoform came into being in the early Holocene(about 11.2 cal kyr BP) and can be divided into the lower and upper depositional units(DU 2 and DU 1, respectively). The unit DU 2, being usually less than 3 m in thickness and formed under a low sedimentation rate, is located between the bottom boundary and the Holocene maximum flooding surface(MFS), and represents the sediment of a post-glacial transgressive systems tract; whereas the unit DU 1, the main body of the clinoform, sits on the MFS, belonging to the sediment of a highstand systems tract from middle Holocene(about 7–6 cal kyr BP) to the present. The provenance of the clinoform differs from that of the typical sediments of the Yellow River and can be considered as the results of the joint contribution from both the Yellow River and the proximal coastal sediments of the Shandong Peninsula, as evidenced by the sediment geochemistry of the core. As is controlled mainly by coactions of multiple factors such as the Holocene sea-level changes, sediment supplies and coastal dynamic conditions, the development of the clinoform is genetically related with the synchronous clinoform or subaqueous deltas around the northeastern Shandong Peninsula and in the northern South Yellow Sea in the spatial distribution and sediment provenance, as previously reported, with all of them being formed from the initial stage of the Holocene up to the present. 相似文献
15.
16.
LINXiaotong LIWeiran DUShujie 《中国海洋大学学报(英文版)》2005,4(2):131-136
The multivariate statistical techniques, principal component analysis, Q-mode factor analysis, correspondence analysis and fuzzy C-means clustering were applied to analyzing the datasets of minor element concentrations in sediment samples of a core collected from the outer shelf of the East China Sea. According to the analysis results, the sediment core Q43 can be divided into three strata with different features in minor elements. The first stratum (unit Ⅰ) is characterized by higher concentrations of V, Cr, Cd and Sc, which are active and inactive elements. The second stratum (unit Ⅱ) is controlled by ultrastable elements V, Ti, Cr, Th, Sc, Pb, etc. The third stratum (unit Ⅲ) is dominated by Ni, Co, Ba, Rb and Mn, which are authigenic and volcanogenic elements. The geochemical features of the core Q43 show environmental changes in the depositional process from the Late Pleistocene to Holocene. 相似文献
17.
陆相层序界面的物质表现及成因类型——以鄂尔多斯盆地中生界为例 总被引：3，自引：1，他引：2
根据野外露头、钻井岩性剖面和地球物理资料等,在鄂尔多斯盆地中生界可识别出的层序界面有古暴露剥蚀面、不整合界面、河流回春作用面、冲刷侵蚀面、岩性与岩相转换面、上超面、最大湖泛面。在详细讨论各类型界面特征的基础上,将成因划分为:构造运动造山侵蚀不整合界面、升隆侵蚀不整合界面、暴露不整合界面、冲刷侵蚀不整合界面、最大湖泛沉积界面5种类型。 相似文献
18.
山东省境内发育有中新生代盆地38处,分布于鲁西、鲁东、鲁北三区.以其地层结构、发育历史分为侏罗纪、白垩纪、古近纪、新近纪4个成盆阶段6个世代盆地.按照盆地的形态特征和成因特点分成单断、地堑、拗陷三种类型.它们同受以沂沭断裂为主的NNE向左行扭断裂或其派生断裂的控制,在间息性运动过程中发生多旋回沉积作用. 相似文献
19.
高速滑坡具有运动速度快、波及范围广的灾害特征, 因此对滑坡启动、加速和静止整个运动过程进行研究很有必要。基于滑面力学特性将滑面分为弹性介质区和应变弱化区, 构建了高速滑坡二维力学模型, 提出了滑坡启动动能计算公式和滑坡运动过程的能量计算公式; 以千将坪滑坡为例, 采用启动动能计算公式得出滑坡的启动速度为2.35 m/s; 依据滑面形态将其运动轨迹划分为快速加速、平稳加速、平稳减速、急剧减速4个阶段, 进行运动过程分析, 得出滑坡最大速度为16.8 m/s, 以滑坡前缘高程所在平面为势能基准面, 分析不同能量与总能量占比的变化情况, 在滑坡的4个运动阶段中, 动能占比分别为9.1%, 25.6%, 15.1%, 0%;摩擦损耗能量占比分别为: 5.5%, 58.8%, 81.7%, 95.5%;势能占比分别为: 85.2%, 14.2%, 0%, 0%;其他阻力能耗占比分别为: 0.2%, 1.4%, 3.2%, 4.5%。研究结论对高速滑坡致灾机制和风险分析具有重要意义。 相似文献
20.
Newly acquired high-resolution seismic profiles reveal a nearshore and an of fshore mud depocenter of f the southern Shandong Peninsula in the Yellow Sea.The nearshore depocenter is distributed in bands along the south coast of Shandong Peninsula.The of fshore depocenter is part of the distal subaqueous deltaic lobe,which deposited around the southeastern tip of the Shandong Peninsula.Between the two depocenters is a linear depression.The mud deposits directly overlie the postglacial transgressive surface and can be divided into lower and upper units by the Holocene maximum flooding surface.The nearshore and off shore units display different seismic structures.The lower unit of the nearshore deposit exhibits basal onlap,whereas the upper unit is characterized by progradation.The lower and upper units of the off shore deposit display distinct acoustic features.The lower unit has low-angle aggradation with internal reflectors generally dipping seaward and truncated by the Holocene maximum flooding surface,whereas the upper unit is characterized by aggradation and progradation landward rather than seaward.Results of geochemistry analysis of QDZ03 sediments and mineral analysis of WHZK01 sediments suggest that the nearshore deposit and the lower unit of the of fshore deposit are derived from the proximal coastal sediments of the Shandong Peninsula and the Huanghe(Yellow) River sediments.The upper unit of the of fshore deposit is mainly Huanghe River-derived.The lower unit of the mud deposit represents a post-glacial transgressive system tract according to dates of core QDZ03,and the upper unit represents a highstand system tract from middle Holocene to the present.These results will be of great significance to further understanding of the transportation of the Huanghe River sediments into the Yellow Sea and the spatial distribution of the subaqueous delta. 相似文献