Supported by the key knowledge innovation projects,i.e., a preliminary study on the theories and techniques of the remotely sensed temporal-spatial information and digital Earth; and a study on the integration of national resources and environment and data sharing, the authors have set up a spatial-temporal information platform by the integration of the corresponding scientific and research achievements during the periods of the 8th- and 9th-Five Year Plan, which comprehensively reflected the features of land-use change, designed a series of technical frameworks on the spatial-temporal database construction based on remote sensing techniques, e.g., the construction of remotely sensed database and land-use spatial database of the mid-1980s, the mid-1990s and the end of the 1990s, which laid a foundation for the dynamic monitoring of land-use change and the corresponding studies. In this paper,the authors have analyzed comprehensively the features of land-use change in the 1990s, revealed the spatial-temporal change of land use supported by remote sensing and GIS technologies as well as analyzed the geophysical and socio-economic driving factors.The findings are as follows: the arable land has been increased in total amount, the balance of decrease in the south and increase in the north was resulted from the reclamations of grassland and forest land. On the whole, the forest land area had a process of decrease, and the decreased area was mainly distributed in the traditional forest areas. Areas with plentiful precipitation and heat in the south, however, had distinct effects of reforestation. The rural-urban construction land had a situation of persistent expansion, and the general expansion speed has been slowed down during the last five years of the 1990s with the exception of the Western China where the expansion speed has been accelerated. The land use change in China in the 1990s had distinct temporal and spatial differences due to two main reasons, which were policy control and economic driving. Hereby, conclusions and proposals brought forward by the authors were as follows: the spatial diversity rules of the modern land use change in China must be fully considered in the future land use planning. At the same time, the pertinence of physical geographical zones must be considered during the planning of eco-environment construction. And, based on the increasingly maturity of the infrastructure, the traditional thoughts on planning and management of resources must be shifted so as to fully realize the optimized allocation of land resources at regional scale.
Urban man-made landscape is a combined conformation of various kinds of artificial buildings by collective human activities.It has a variety of configuration and evident adumbration as well as the characteristics of discontinuity and irreversibility. The development of the urban man-made landscape of Dalian,different from the general development law of the urban man-made landscape,witnesses the fallowing process of the spread of the single core extent in the shape of a hoof--the annular banding spread--radiation of multicores, the spread of belt . Its development mechanism is based on geological condition. Urban planning acts as its leading factor,while socio-economic development as its motive force. Probing into urban man-made landscape essential feature and development mechanism on time and space distribution can offer efficient decision basis for the development of urban construction and the protection of the fragile urban eco-environment.Whether the development of the urban man-made landscape is rational has important influence on urban construction and urban environment. The orderly and rational development will bring prosperity to the city; otherwise it will not only bring confusion to the development of the city, but also cause urban feature stereotyped,which will reduce the economic value of the city and cause a series of urban environmental problems.So we put forward some views on the development of the city in light with urban man-made landscape to policy makers for their reference:1)geological survey and mapping work,should be fully carried out so as to offer scientific basis for rational urban planning;2)urban construction and development plan should have certain leading in order to guarantee the historical continuity in the development of urban man-made landscape;3)the development of urban man-made landscape should give prominence to the nature and function of the city by highlighting its distinct individual character;and 4)the development of urban man-made landscape should take people's benefits first, and urban construction should pay even more attention to environmental protection.Substantial development of urban man-made landscape will cause expansion of space dimension size to a certain extent,inducing a series of urban eco-environmental problems. So, the harmonious sense of pursueing"harmony of man with nature" just should be a supreme goal of the urban construction.
The mechanism of long-term shoreline evolution of large-scale estuarine deltas under conditions of water and sediments flux changes (WSFC) is one of the hot topics of current global change research. In case of the Yellow River delta, the WSFCs are considered to play an important role in the evolution of delta because the river flow has been broken off for several times since the 1970s,which has changed the estuarine shoreline greatly. So it is urgent to analyze the modern the Yellow River delta and its adjacent area quantitatively and carry out in-depth studies on the mechanism of dynamic balance between the erosion and extension of shorelines under different water and sediment fluxes conditions in order to strengthen the theoretical basis of the delta's sustainable development. To reach that point, the mechanism of dynamic balance between erosion and accumulation under different water and sediment fluxes should be found. At present there are usually four kinds of models available to simulate the estuary shoreline formation and geomorphologic evolution of the great river deltas, which are statistic model, geometric model, depositional dynamics model and numerical model. The first two models do not describe the mechanism, and they can't be used to explain the long-term evolution of a great river delta coast; and the other two models can only compute critical values of the sediments' starting-up, transporting, and sinking processes in the very short cycle, although they can explain the mechanism in some ways. Therefore, there is still lack of mature theory on the mechanism of long-term templral (over one year) and macro spatial (the whole great river delta and its adjacent area) shoreline evolution modeling.After analyzing eroding and depositing processes carefully, we found it is necessary to conduit an in-depth study on the near-shore residual current dynamic process under conditions of the River's WSFCs, for Lagrange residual current is the key dynamic factor not only for discharging sediments long-term transportion but also for coastal and seabed's erosion and deposition. Finally the paper puts forward a tentative plan on building a macro mechanism model and offering a solution to the key problems including scaling scale, building and expressing total residual current field, and computing critical values of the sediments' resuspension, transportation and deposition.
A number of research approaches, such as digital analysis, relationship between river mouth extension and channel evolution, sedimentary analysis,channel topographic map comparison, and hydrologic regime research, have been presented in studying the adjustment processes of the river bed longitudinal profile morphology of the lower Yellow River.Theoretically,it is basically concerned about the evaluation if the role of downward and headward silt-clearing.Comparing the river bed longitudinal profile of different years in terms of the data of water level corresponding to the discharge of 3000 m 3 /s, Zhang Ren(1985) concluded that the longitudinal profile of the lower Yellow River had been elevated during the 1930s to the 1970s.By means of digital analysis, Jia Shao-feng et al.(1992) have theoretically demonstrated that the retrogressive aggradation due to continual base-level rise was the basic reason for the uniformly elevated channel bed of the lower reaches of the river. On the basis of the change of flood-plain height and the associated river mouth extension, Wang Kai-chen(1982) has also indicated that the river bed longitudinal profile at downstreams was uniformly elevated. Pang Jia-zheng et al.(1982) and Xian Jian-heng et al.(1980) have shown that the main controls on the lower Yellow River's longitudinal profile were channel extension and course changes, and that the effect of the headward degradation and aggradation declined gradually from dowmstreams to upstreams and finally was over in Luokou.By the statistical analysis of 5-year water level change with a discharge of 3000 m 3 /s, Yin Xua-liang(1991) has shown that annual water level change was different and degradation and aggradation should have been caused by downward factors.Wei He-long et al.(1996) have indicated that the downward degradation and aggradation of the lower Yellow River was principally related to the variations of discharge and the silt content and that the headward degradation and aggradation was resulted mainly from base-level change at downstreams which was basically due to change of river length.To sum up, although for the lower Yellow River a number of research methods were concerned with the self-adjustment of the river bed longitudinal profile morphology, the morphological indexes, gradient and concavity had been paid little attention to. This paper calculated the values of gradient and concavity indexes for the long-term and long-distance river bed longitudinal profile of the lower Yellow River using the least square method and the parabolic partial differential equation. Minor variations in both the gradient index and the concavity index indicate that the entire lower Yellow River has almost uniformly elevated its river bed over a long period of time in the self-adjustment of the river bed longitudinal profile morphology, and that the lower Yellow River has become an aggradational peneplane reach. The nearly uniform elevation of the lower Yellow River may have resulted from downward sedimentation and headward sedimentation caused by relative base-level rise in the river mouth. The aggradational process had introduced underground streams to run on the surface, in such a case, the entire lower Yellow River became an old-stage stream.The old-stage stream implies that the channel development may have achieved a critical stage which heavy aggradation and channel decline may have occured. On the other hand, the capability against historical floods may have greatly decreased, and disasters may have frequently happened.
Based on the data from hydro-metric stations on the Yellow River and its tributaries, we have studied the grain-size characteristics of suspended sediment in relation to concentration and discharge. The middle Yellow River basin is located in a transitional zone from sub-humid to semi-arid climates, and covered by a thick loess mantle.In the neighboring desert areas in the northwest, the surface material of the Loess Plateau exhibits some remarkable areal differentiation in grain-size and forms three zones known as sandy!loess, (typical) loess and clayey loess from northwest to southeast. Controlled by these physico-geographical conditions, the grain-size of river sediment shows some particular characteristics. The plot of suspended sediment grain-size against water discharge and suspended concentration indicates some complicated variations. When the discharge or suspended concentration is low, the median size is relatively coarse. With an increase in discharge and concentration, the median size decreases to a minimum, and then increases again. During the low flow season, the relatively clear baseflow may scour the bed, so the suspended sediment is relatively coarse. Entering the rainy season, rainstorm runoff carrying fine loess material flashes to the river, making a decline in suspended sediment grain-size. However, during high-intensity rainstorms, hyperconcentrated flows often occur. Hyperconcentrated flows are a liquid-solid two-phase flow. The mixture of water and fine sediment is the liquid phase, and its unit weight is larger than clear water. The relatively coarse sediment particles suspended in the liquid phase constitute the solid phase. Hence, with the increase in concentration, more coarse particles can be set in suspension, and the median size increases again.For rivers located in different zones of surface material, some complicated relations between suspended load grainsize and mean annual suspended concentration has also been found. Double-value relations between grain-size and concentration exists, which can also be explained by the specific physico-geographical settings and the behaviors of hyperconcentrated flows in this area.
Sediment dispersal at the river mouths has been an important topic in the fields of geomorphology and hydraulics for a long time and estimating sediment budget of the deltas is a principal method for quantifying the sediment dispersal system at many river mouths. Many reports about sediment dispersal at the Yellow River mouth have been given previously using this method. However, since the dry bulk density of deposits in the delta and the boundaries set for calculating the volumes of deposits did not receive a proper treatment, big discrepancy existed between estimates of sediment budgets of the delta provided by the previous studies.Considering the effects of grain size composition, burial depth, and exposure conditions on the dry bulk density of deposits and based on abundant data about the dry bulk density of deposits in the delta, this study defined the dry bulk densities for the deposits in the delta plain and buried delta front deposits, buried prodelta, exposed subaqueous prodelta, and newly deposited top 1 m layers on the delta front. Combining the constructed models of dry bulk density for different depositional settings with the results of analyzing the sedimentary framework of the delta, sediment budgets at Diaokouhe lobe of the Yellow River delta were calculated. The foot of the delta front slope was set as the outer margin of area for defining the sediment budgets. This margin is of geomorphologic significance and is easy to be located on the surface of delta recorded by the bathymetric data. Results show that sediment deposited in the delta plain and front of the Diaokouhe lobe over the period from 1965 to 1974 was about 7.10×109 tons, accounting for 73.5% of the incoming sediment. Errors resulting from ignoring clay layers in the deposits on delta plain and front, consolidation of soft layers underlying delta deposits, and deviations in records of the incoming sediment were proved to be about 2.6% for the percentage of sediment deposited in the delta, suggesting the higher reliability of the sediment budgets given by this study. From the mass and volume of sediments deposited in the Diaokouhe lobe over the period of 1965 -1974, a mean dry bulk density of 1.36 g/cm3 was acquired. On account of the dominance of silt in the deposits of the delta, it seems to be an appropriate approximation of the mean dry bulk density for the deposits in the other lobes of the delta.
This paper mainly approached the famous hypothesis-Environment Kuznets Curve concerning municipal solid waste discharge in urban area of Shanghai. The municipal solid waste dealt with in this paper especially included construction waste and domestic waste, which come from business, public utilities, office and households in Shanghai city area. Correlation analysis between the annual statistics of per capita GDP and total municipal solid waste discharge in Shanghai from 1978 to 2000 showed that an obvious invert U-shape Kuznets curve existed between these two indicators. The simulated calculation illustrated that the turning point of this Environment Kuznets Curve would be per capita GDP RMB 33 441 yuan, at which the corresponding waste discharge would be over 7.79 million tons. In 2000, per capita GDP in Shanghai reached 34 547 yuan, the annual municipal solid waste disposal cleared was 7.41 million tons that was less than the theoretical simulation data. It indicated that the turning point occurred around the year 2000 and Shanghai will enter into the new period, in which municipal solid waste discharge will show a gentle decreasing tendency following economic growth. This paper further discussed the waste components changes in Shanghai city. The ration of construction waste that reached the top level in 1998 accounted for 42.8%,which was the reflection of great change in Shanghai city construction throughout the 1990s. Data analysis also showed that the decreasing rate of municipal solid waste disposal cleared per unit GDP was much lower than the GDP growth rate. It is important to regulate the trend of municipal solid waste discharge in Shanghai. To implement the policies such as waste producers taking their full responsibilities,promoting more waste services through market activities and setting multi-investment model to improve solid waste collection and disposal, that will benefit a lot for Shanghai municipal solid waste control.
There have already a lot of research results about the influences of the Three Gorges Reservoir on water environment in backwaters in the mainstream of the Yangtze River, but environmental impact assessment work about tributaries in the backwater area is not sufficient. Since eutrophication has occurred in many reservoirs in China, much attention should be paid to the issue that whether there will be eutriphication in the backwaters of tributaries after water storage in the Three Gorges Reservoir.Firstly, this paper estimates changes of hydraulic parameters (such as water depth, flow velocity, water surface area and water volume stored) in tributary backwaters before and after normal operation of the Three Gorges Reservoir in 2009 and predicts pollution load level (TN and TP) in 2010. And then by using Box Model,it analyses the Three Gorges Reservoir's influences on eutrophication in tributary backwaters of the Yangtze River in Chongqing section. The results show that, with average water depth of 15m in backwaters tributaries,there should be no eutrophication problem on the whole. However, it is possible for water near the bank along the reservoir with water depth under 1 meter to have the eutrophication problem in partial.A water body will subject to eutrophication of moderate level to higher level if TP concentration ranges between 0.05 mg/L and 0.11 mg/L according to standard of eutrophication indicators of Institute of National Public Hazards of Japan. Because TP concentration in backwaters of some tributaries of the Three Gorges Reservoir will certainly exceed 0.05 mg/L, we can also conclude that although there will be no higher level of eutrophication in tributary backwaters, there will be moderate eutrophication.
Forest degradation has been widely acknowledged to be the main cause for the 1998 Yangtze River flooding. Of the two crucial reasons of for flooding,climate fluctuation and land-cover change,which one on earth acted as the leading factor? In order to probe this issue, the Suomo Basin on the upper reaches of the Yangtze River was chosen as a study area. About forty years' climate fluctuation and land-cover changes in the Suomo Basin were analyzed in this paper. Precipitation deceased by 19.3 mm from the 1960s to the 1970s and increased by 61.2 mm from the 1970s to the 1990s. According to three decades land-cover maps, the primary land-cover changes are that forestland turned into sparse and shrub by forestland, and the shrubby and sparse forestland turned into grassland. Forestland deceased by 12% from 1970 to 1986. A dump hydrological model, CHARM (Climate and Human Activities-sensitive Runoff Model), was adopted to simulate the impact of climate fluctuation and land-cover changes on runoff discharge and to divide their contributions to annual runoff. From the 1960s to the 1980s, runoff depth increased by 45.7 mm. Among them, 63.9% was caused by climate fluctuation, 20.8% was the result of the land-cover changes and the remaining 15.3% was system error. In other words, 1/5-runoff change was caused by land-cover change and 3/5-runoff change was caused by climate fluctuation. From this simulated conclusion, we can get an elementary explanation about the Yangtze River flooding in 1998. Possibly it is climate fluctuation,rather than forest degradation that is the leading factor for the flood.
The increasing greenhouse gas in atmosphere will lead to an increase of 1.1-3.1 o C in mean annual temperature (MAT) in next century as predicted by IPCC (2001). Such an increase in temperature will considerably alter the current regimes of precipitation, hydrological cycle and thus water resources. The impacts of these changes will be particularly severe in arid and semi-arid regions around the world. In China, it may be most severe in North China and Northwest China, shown by some previous investigations.The Huaihe drainage basin (111°55'-120°45'E, 31°-36°N) is located in the transitional belt of the sub-tropical and temperate zones in eastern China. The MAT is 11-16 o C.The mean annual precipitation(MAP) is 883 mm, 50-80% of which falls during May-August in upstreams of Huaihe River and areas south of it or June-September in other areas with mean annual runoff depth being ～231 mm. The Huaihe drainage basin is economically significant as both industry and agriculture are rather developed. A general assessment on climate-change effects on runoff may be still somehow helpful for the regional water resources management and economic development and planning in the future. We have therefore selected the Huaihe drainage basin as our study area in this research. We assume an increase of 1, 2 and 3 o C in MAT and mean seasonal temperature(MST), and a change of 20%, 10% and 0% in MAP and mean seasonal precipitation(MSP). Then 15 climate-change scenarios were constructed by integrating each temperature change with each precipitation change. The general structure of a nonlinear model on climate factors and runoff relationship was established with multi-variable regression method. Then by analyzing meteorological and hydrological data of 20 years for three sub-catchments of the Huaihe drainage basin, mean annual and seasonal values of temperature, precipitation and runoff were respectively calculated from the corresponding month values. Furthermore, mathematical models relating mean annual runoff to MAP and MAP and relating mean seasonal runoff to MAP and MAP were established with the aforementioned calculated data. Runoff was subsequently estimated with statistical model for the sub-catchments under the 15 climate-change scenarios.The results allow a preliminary assessment of influences of the climatic changes on runoff in the near future. Runoff will generally increase with increase in precipitation and decrease with temperature rise. For a given climate-change scenario, the responses of runoff of different sub-catchments vary, which may reflect the differences in physical characteristics and their influences on runoff in different sub-catchments. For a given sub-catchment, the responses of each season's runoff to each of the climate-change scenarios also vary, which may manifest monsoon climate influence on runoff. The dry-and-warm climatic conditions may dramatically reduce runoff and hence have severe or even disastrous effects on economic development in this area.
Stockbreeding in northern China was a production sector separated from primitive agriculture. Its generation and development experienced the following process. About 5000 years ago, northern China was witnessing a climatic warm period,farming and hunting were basically the predominant human activities with less proportion of stock preeding in areas north of the Great Wall. From that time on to 3500 years ago, agricultural practices became less and less with the climate turning to be colder and drier. On the other hand, stockbreeding and hunting became more and more important. The structure of production changed from original farming and hunting in predomination to stockbreeding and hunting in predomination. But the stockbreeding then was different from nomadism, because it had intimate relationship with agriculture. The archaeological researches in China had proved not only that stockbreeding came from agriculture, but also that the rise of nomadism was related to the use of saddlery. About 800 B.C., the northern tribes in China had been proficient in using saddlery, they gave up completely,settlement life and the genuine nomadism appeared then.In the process of discussion, this paper points out that early stockbreeding belonged to breeding depended on agriculture. Naissance of the nomadic life was later than stockbreeding,making it broken away from agriculture completely. Climate changes were important factors that directly made stockbreeding broken away from agriculture. With this development, stockbreeding turned to the nomadic life. This article discusses the relationship between naissance of the nomadic life and environmental changes. The conclusion is that, when life in the grassland changed into nomadic, the local people did not leave their homeland, the only change they made was that they shifted their production mode from agricultural to nomadic.
Urban social space is an essential topic of urban planning and urban geography. Urban physical space is one of the important impact factors of urban social space,and transportation corridor is a most active element of urban physical space,which affects the urban social space by invasion,separation, succession and so on. Dewai Street is one of the main transportation corridors in Beijing City. It was 4 times widened after its reconstruction in the spring of 2002. Taking it as an example, this paper analyses the social effect upon its passing area. As far as the academic significance of this case study, the paper interprets the mechanism of American geographer R. A. Murdie's model of urban social space, which shows how transportation corridor affects social space by cutting the communication of its passing community. Upon entering the 21st century, some geographers in US and UK have been calling for linking material research and immaterial research of urban space, such as L. Lees and P. Gober. The case study of Dewai Street and its passing community is a response to the call. As far as the practical meaning is concerned, the paper puts forward that the integrity of urban living units should be kept up. At the same time, the paper points out the distinction of different kinds of social space cells while adapting to the change of physical space. And AGIL scheme of T. Parsons serves as an explanation tool to interpret why Dewai Community could adjust itself to the space change so quickly.
The conversion from farmland to forest or grassland is a great action of eco-environmental construction in Northwest China, but necessarily it may directly influence the grain production of that area.Proceeding from the conversion scale and the grain response in Northwest China, and taking county as the unit, this study discusses the question of cultivated land and grain production in the five provinces ( autonomous regions) in Northwest China. According to analysis: excluding other factors,if all the farmlands with a slope being greater than 15 degrees are to be converted, the defarming area will reach 392.8 104 ha, or 23.5% of the total farmland area.Considering the present grain-production and consumption level, the authors think it is impossible to convert farmland with a slope greater than 15 degrees; if all the farmlands having a slope greater than 25 degrees are converted,according to the legal provisions,the defarming area will reach 153.6 104 ha, or 9.2% of the total farmland area, and the output reduction of grain will be 71.21×104 t ,or about 2.2% of the region's output in 1996. The impact on per capita grain available of the whole region is slight.On the premise of per capita 0.1 ha of cultivated land, if farmlands with a slope greater than 15 degrees are converted, then the defarming area will be 347.80ha,20% of the present land area, and the corresponding deduction of grain is going to be 234.5 104 t, which is 7.3% of the 1996 grain production.The percentage of grain deduction is about 10 in Gansu, Shaanxi and Qinghai provinces.The impact of conversion on output of grain is obvious. In view of the conversion scale and its influence on grain production, this research proposes two policy advises: (1) To coordinate conversion from farmland to forest or grassland with local ecological environmental construction, make overall plans, formulate respectively guidance for different types of areas, give top priority to what is the most important, implement by stages and in groups and carry out with the slope transformation of cultivated land in step.(2)To implement "storing food in land" project, develop reserve land resources in a planned way, strengthen farmland capital construction and regional grain production base and improve the integrated production capacity of land resources of Northwest China.
On the framework of regional advantages, industrial correlation, science and technology contentment, market potential and ecological level, three indexes systems for leading industrial assessment of industry, tertiary industries and agriculture are established.The weights of indexes are computed by means of IAHP(Improved Analysis of Hierarchy Processing).A new model of unique-index evaluation (process of unit-elimination)-nonlinear effective function is proposed, which can describe the coordination of each index more effectively.Quantitative evaluations are made on the industries-specific industry, tertiary industries and agriculture, with the selection of five leading industries,namely,electronics and information industry, bio-technology industry, optical-mechanica -electronica integration, manufacture of transportation facilities, manufacture of electrical machinery; six leading industries of tertiary sectors, namely science and technology and education, information consultation, finance, tourism, commercial, real estate; and one leading industry of agriculture-plantation.The key points of industrial construction adjustment and optimization orientated to Jinan city are discussed: 1) industrial construction to speed up the development of tertiary industries, strengthen industry, develop the primary industry steadily; 2) industrial organization to bring about the combination of large-, medium- and small-sized enterprises, put emphasis on large-sized enterprises, open medium- and small-sized enterprises; make co-existence of different economic components and take the state-owned enterprises as the main-body; co-develop city, town and county, put the emphasis on urban areas;and 3)industrial technology to take the hi-tech as the leading, make it as the incubator and driver for the future economic development of Jinan City
On the basis of the field surveys organized by WWF in the wetland restoration areas of the Dongting Lake, this article analyzes the characteristics and restricted factors of agricultural labor transfer in the wetland restoration areas of the central Yangtze Valley. The results of the study are as follows: the rate of the surplus agricultural labor transfer is much lower on the whole in the investigated areas, and the outflow labor is mainly young people whose educational level is so low in general that they cannot satisfy the needs of labor markets in cities. In addition, the employment information is inadequate, the job opportunities are few, and the transfer cost for peasants is comparatively high. Those factors also restrict off-farm employment in the investigated areas. Finally, according to the situation of the rural economic development and the employment of the labor force in the investigated areas, along with relative research materials at home and abroad, the article identifies some ways for offective transfer of agricultural labor force. They are as follows: to adjust internal agricultural structure and allocation in the lake areas, exploiting the employment potential within the agriculture; to strengthen the development of agricultural industrialization; to adjust the development direction of the township enterprises strategically, combining with the construction of town- and township-run enterprises; to speed up the process of rural urbanization; to develop the eco-tourism of the wetlands; and thus to take active measures to drive the surplus agricultural labor force to other places.
