A 3D diagnostic model including a suspended sediment transport module, ECOMSED, driven by the monthly discharge and sediment load of the Yellow River, was applied to the Bohai Sea during 1983-1984. The simulations on temporal-spatial variety of SPM (Suspended Particular Matter) concentration, sediment flux, and deposition rate were carried out. It could be discerned that, the SPM concentration presented distinctly seasonal variety, and the variability characteristic was similar in two years. Some of the fine sediment of the Yellow River extended to the western bank of the Liaodong Bay, but most of the sediment deposited around the estuary of the Yellow River, and the deposition flux progressively decreased with the distance to the estuary increasing. The deposition kept at a rate of 0.05-0.1 mm/a, which is close to the in situ data. There were two areas of high SPM concentration in the Bohai Sea, one of which can be attributed to the Yellow River discharge, and another one located at the seas with intensive resuspension power may be due to the tidal current energy. The sediment poured from the Yellow River was transported mainly along the track of the Lagrange residual circulations. In one word, the suspended load transport was basically attributed to the wind-driven and tidal-forcing Lagrange residual circulations. The resuspension flux was related to the bottom currents: the larger the current speed, the more the sediment resuspended.
On the basis of the characteristic analysis for river load movement, the minimum instream flow requirements for transporting sediment was considered as a certain volume of intream flow required to transport per weight sediment when the sediment transportation is at balanced state of erosion and deposition. Through the analysis of sediment carrying capacity (Su*) and a comparison with the sediment concentration (Su) at the upper reach, a method to estimate minimum sectional instream flow requirements for transporting sediment of river was proposed according to Su ≤ Su* and Su > Su* respectively. Then, this method was applied to estimate the monthly instream flow requirements for transporting sediment in the lower Weihe River. The temporal scale of typical years included p = 25% (1963), p = 50% (1990), p = 75% (1982) and p = 90% (1979), and the spatial scale of the study areas included Xianyang section, Lintong section and Huaxian section. The results show that the average monthly instream flow requirements for transporting sediment in flood seasons are higher than those in non-flood seasons. Generally speaking, from Xianyang section to Huaxian section, the sectional instream flow requirements for transporting sediment in both flood seasons and non-flood seasons of each typical year increase. Estimated for a wet year (p = 25%), the annual instream flow requirements for transporting sediment of Xianyang section, Lintong section and Huanxian section are 63.67×108 m3, 97.95×108 m3 and 103.25×108 m3 respectively; estimated for normal year (p = 50%), the instream flow requirements for transporting sediment of Xianyang section, Lintong section and Huanxian section are 49.71×108 m3, 83.27×108 m3 and 85.08×108 m3 respectively; estimated for a dry year (p = 75%), the instream flow requirements for transporting sediment of Xianyang section, Lintong section and Huanxian section are 30.17×108 m3, 55.14×108 m3 and 65.32×108 m3 respectively; and estimated for a much drier year (p = 90%), the instream flow requirements for transporting sediment of Xianyang section, Lintong section and Huanxian section are 23.96×108 m3, 37.91×108 m3 and 38.92×108 m3 respectively. It can be found that from wet year to dry year, the instream flow requirements for transporting sediment of each section decrease.
By scouring experiments, the changeable process and characteristics of sediment yield in the slope-gully system with different coverages and spatial location of grass were studied. Results showed that the sediment yield decreased with increasing grass coverage at smaller water inflow rates in scouring experiments. The sediment yield with different grass locations on the sloping surface was in the order of upper > middle > lower. At larger water inflow rates, the differences of sediment yield among various grass coverage were enlarged, whereas the changeable tendency of sediment yield with different grass locations on the sloping surface was not very obvious. The proportion of sediment yield from the gully increased in an exponential relationship with increasing grass coverage, and the increasing degree for large water inflow rate is larger than that of the small one. When the grass was located on the lower position on sloping surface, the influence for accelerating gully erosion is the largest. The changeable process of sediment yield in slope-gully system was to increase first and then to decrease.
The natural environment of the northeastern part of Qinghai province has close relation to global climate changes. In this region there are highly developed prehistoric culture, complete sequences and plentiful vestiges. So it is the typical area where the research of the impact of climatic change on the prehistoric culture of China can be conducted. By researching the regional climate and archeology with the methods of GIS and mathematics analysis, we can find that the climate tended to be dryer and colder at 4 kaBP, so, the Qijia culture dramatically became declined at 3.9 kaBP; the climate kept a dry and cold situation at 3.6 kaBP, which promoted the appearance of the Xindian and Kayue cultures and the increase of a lot of relics; the Qijia culture belongs to a farming culture, the Xindian culture inherited the productive activity from the Qijia culture with its regional scope changing smaller to low sea-level, low mountain and river valley areas; but the Kayue culture changed its own productive pattern and produced a new economic way-animal husbandry after the abrupt climate changes, and its regional scope became the largest in prehistoric culture age. Pre-historic residents took different measures due to the abrupt climate changes, then different cultures developed. Climate change is a major driving force that made prehistoric cultures diversified. It is also one of the most important reasons why large selttlements cannot be maintained for a long time and civilization process suffered setbacks.
Huaihe River basin in Anhui is not only a transitional zone of physical geography, but also an interaction area of many cultures in China. Fishing and hunting played the dominant roles in Shishanzi cultural period; fishing and hunting as well as farming were equal important in Dawenkou cultural period; and priority was given to farming over fishing and hunting in Longshan cultural period. Using the field archaeological data and the sporo-pollen and age data of the drilling cores, we analysed Neolithic cultural development and environmental evolution in Huaihe River basin, Anhui, and discussed the relationship between culture and environment in the area by combining archaeological research results with researches of environmental evolution. The Neolithic cultural development was strongly impacted by the environmental change. The primitive culture (Shishanzi) was developed in the beginning of Holocene Megathermal Period when regional feature of culture was distinct. From 6.5 kaBP to 5.5 kaBP, the climate became warmer and wetter. Flood and waterlog frequently occurred. As a consequence of the impact of such a climate and high sea level, the environment of the earth's surface deteriorated in Huaihe River basin, Anhui, causing the interruption of the Neolithic cultural development and the lack of archaeological sites. From 5.5 kaBP to 4.0 kaBP, the climate changed from wet to dry, the natural environment was favorable to human survival. Dawenkou Culture and Longshan Culture flourished in this period. The Neolithic cultural development, the amount of the sites and their distribution characteristics in Huaihe River basin of Anhui differed apparently from those in central China and Shandong Province.
Karst has been regarded as a fragile environment by environmental scientists. Because of karst system with a low capacity, it is difficult to restore if once disturbed. Changes in environment are not unique throughout the karst region, but a karst region is more sensitive than other regions. In the present study we analyzed the land use changes from 1982 to 2003, and assessed the effects of land use changes on pH value, organic matter (OM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP), available potassium (AK) in soils of Xiaojing watershed, a typical karst agricultural region in Yunan province, Southwest China. The results indicate: (1) The total land converted covers an area of 610.12 km2, of which 134.29 km2 of forestland were converted into cultivated land, and 210 km2 of unused land were converted into cultivated land during the past 20 years in Xiaojiang watershed. (2) The rapid growth of population and the economic development were the main driving forces of cultivated land change, and the comparative economic benefits from the macro-policies such as eco-environmental protection were important driving forces of forestland change in Xiaojiang watershed during the past 20 years. (3) Because of land use change, the soil properties have been changed significantly. The pH value, OM, TN, TP, TK, AN, AP and AK in soils in 1982 were 6.3, 38.02 g/kg, 1.86 g/kg, 1.63 g/kg, 10.94 g/kg, 114.42 mg/kg, 11.65 mg/kg and 64.69 mg/kg, respectively; and those in 2003 were 6.73, 25.26 g/kg, 1.41g/kg, 0.99 g/kg, 12.6 g/kg, 113.43 mg/kg and 11.11 mg/kg, 151.59 mg/kg, respectively. Pared samples t-test of the tested indices of soil properties indicate that those indices have changed significantly during the past 20 years. (4) Because of the differences of land use change, the soil properties change differently. The contents of the soil OM, TN, TP in 2003 were significantly lower than those in 1982 after the forestland and unused land were converted into cultivated land, but the pH of soil increased significantly in 2003, especially the properties of the soils developed from the carbonate rock strata changed most significantly. The soil properties change was mainly attributed to deforestation, water and soil erosion, and the low land management level after the forestland and unused land were converted into the cultivated land. Because of lack of the vegetation cover and the land management, the contents of soil OM, TN, and TP for short-time reforested land also decreased, but the soil pH increased. Because of the use of more fertilizer and the improvement of land management, the soil properties improved significantly after the cultivated land was converted into orchard land. But due to unreasonable human activities to the fragile soils in the karst region, the land became rock desertified. The content of the soil OM, TN, TP, AN and AP decreased significantly, but the soil pH increased significantly after land converted became rock desertified. (5) Also, with the changes in land use and soil ameliorative measures, the modifications of properties of soils developed from the carbonate rock strata were more sensitive than those from the sandstone strata.
The Zhujiang Delta has experienced a rapid land cover change, especially urban expansion over the past 25 years due to accelerated economic growth. This paper reports an investigation into the application of the integration of remote sensing and geographic information systems (GIS) for detecting land cover change and urban growth, and assessing their impact on land surface temperature in the region. Remote sensing techniques were used to carry out land use/cover change detection by using multitemporal Landsat TM/ETM data, and retrieve out the land surface temperature by using single Landsat TM/ETM 6 thermal infrared data. The integration of remote sensing and GIS was further applied to examine the impact of land cover change and urban growth on land surface temperatures. The results revealed a notable and uneven urban growth in the study area. This urban development has raised land surface radiant temperature by 8.9K in the urbanized area. The integration of remote sensing and GIS was found to be effective in monitoring and analyzing urban growth patterns, and in evaluating urbanization impact on land surface temperature.
Karst rocky desertification in karst areas of Southwest China is an important obstacle for the sustainable development of the locality. Many researchers have paid more attention to this issue. Based on the previous research, this paper selects Guizhou province as the research area, quantifies the various indexes influencing the karst rocky desertification, using the GIS technology to get the spatial data, and builds the RBFN (Radial Basis Function Network) model for hazardous assessment. After training the relevant data of the different counties with karst rocky desertification, we get the parameters of the model, and then evaluate the karst rocky desertification. The result shows that the whole southwestern part of Guizhou province is a high hazardous area to karst rocky desertification, the northern part is moderate and the southeastern part, slight. Comparisons with other researches show that the result is in conformity with actual conditions, proving the reasonability and applicability of the RBFN model.
Taking the alluvial plain oasis as a study case, we have investigated and evaluated the oasis soil properties related to different land-use systems during the process of the transformation of arid desert to oasis. The land-use systems selected consist of an annual crop field with a tillage history of less than 3 years, annual crop field of 3-6 years, annual crop field of more than 6 years, perennial crop field of less than 4 years, perennial crop field of 4-6 years, perennial crop field of more than 6 years, abandoned farmland of more than 3 years, woodland of more than 6 years, ecological forested land, natural shrubbery land, desert steppe and saline or alkaline field. We deliberately collected 5 soil samples in the different areas for each land-use system at the topsoil (0-20 cm) and subsoil (20-40 cm). The soil samples were sent to soil laboratory. We have employed SPSS statistical software to analyze the soil property data. The results show that: (1) The soils are mainly composed of sand and silt. Different land use systems significantly affect the sand, silt and clay distributions. Sand tends to decrease with increasing years of land cultivation and silt and clay trend to increase in the oasis soil. (2) Soil pH and nutrients significantly differ with the land-use systems. Soils of strong human-disturbed land-use systems presented a higher fertility level than those of other weak human-disturbed land-use systems. Oasis soil nutrients tend to increase with the increasing years of human disturbance. (3) The effect of land-use systems on soil salinity is significant. The soils of strong human-disturbed land-use systems have a lower salinity than those of weak human-disturbed land-use systems as a whole. The soil salinity usually tends to decrease with the decreasing years of reasonable human disturbance.
To obtain an overview of land use effects on the accumulation of Pb in the soil, 600 samples were collected from Beijing. The results showed that the geometric mean of all soil samples was 26.6 mg/kg, significantly higher than the background concentration of Beijing soil (24.6 mg/kg). Based on the assessment compared with background concentration, increasing of Pb was found to be the highest in greenbelt and orchard and to a somewhat lesser extent in vegetable field and paddy field, whereas anthropogenic input seemed to be less important in natural soil. And the concentrations of Pb in greenbelt and orchard were significantly higher than those in other land use types. Using baseline as the criterion, the orchard showed the highest ratio beyond the limit for 21.4%. Corresponding values of greenbelt, vegetable field, paddy field, and cornfield were 18.2%, 11.1%, 8.3% and 5.2%, respectively and 7.2% for the total samples. The samples over the limit were mainly distributed in districts of Changping, Chaoyang, Daxing, Fengtai, Haidian and Shijingshan. The six districts were attributed with high ratios beyond the baseline limit for soil samples. Therefore, the concentrations of Pb in the soils declined gradually with the increment of the distance of the soils from the city zone. Through present investigation, it was found that the impacts of human activities of atmospheric precipitation, landfill of waste and fertilizer application are probably the important reasons for Pb concentrations under different land-use types.
As the embodiment of human activities, the change of regional industrial structure is an important driving factor of land use change, and also makes the change of surrounding eco-environment. Therefore, research on the change of regional industrial structure and associated effects on eco-environment is, not only the helpful complement of the research of land use change, but also the key content of the research on sustainable development, human-land relationship, and geographical response on global change today. In this paper, on the basis of qualitative analysis of the influence of different industrial development on natural eco-environment, we will construct the influence coefficient of different industries on natural eco-environment, and corresponding influence index of industrial structure on natural eco-environment, so as to evaluate the eco-environmental effect of the change of regional industrial structure. The case study in Lijiang city, Yunnan province showed that, during the past 11 years, there was great change in industrial structure in Lijiang city, which experienced double industrial structure transformation. While the influence index of industrial structure on natural eco-environment was moderate, which declined year by year, indicating that the change of regional industrial structure have exerted an active eco-environmental effect.
Based on the improvement of current international major customer satisfaction index models, and taking the characteristics of tourist attraction into consideration, this paper puts forward a creative model of Tourism Attraction Customer Satisfaction Index (TACSI). It is a structural equation model with casual relationships, which is made up of 7 latent variables and 23 observed variables. There are 11 kinds of positive and negative correlativities among the 7 latent variables. Trunk Hill Park in Guilin is taken as an example in empirical study. By means of LISREL, the test result on TACSI model indicates that the measurement model has high goal dependability since the observed variables have a significant effect on customer satisfaction; the path coefficients between the latent variables are basically consistent with the assumption; and the whole TACSI model has a good goodness of fit. In addition, the authors compare the fitness result of TACSI model with ACSI model, which shows that TACSI model is more feasible because it can explain the variables better than ACSI model.
Based on the per capita GDP dataset at the county level in Jiangsu province from 1978 to 2000, this paper attempts to apply spatial Markov chains to investigate the spatial and temporal characteristics of regional convergence in Jiangsu. Firstly, all the per capita GDP data in Jiangsu are classified into 4 different classes by annual provincial average. Due to the changes in the regional development strategies over time, the whole period is then divided into two sub-periods (1978-1990 and 1990-2000), and two Markov transition probability matrices for these two periods are estimated respectively for comparison. Secondly, two kinds of maps are accordingly made in order to visualize spatial patterns of class transitions, one for region, and the other for region and its neighbors. Finally, conditioning on each region's spatial lag at the beginning of each year, spatial Markov matrices for the two different periods are constructed. The conclusions are drawn as follows: (1) The process of regional convergence in Jiangsu has been globally characterized by "convergence clubs" since 1978, but this trend in the 1990s is sharpened and statistically different from that of the period from 1978 to 1990. (2) Those regions and their neighbors that both experience upward mobility are located in southern Jiangsu, while the regions or their neighbors that move downwardly are mostly found in northern Jiangsu. (3) Regional per capita GDP class transitions in Jiangsu are highly constrained by their geographical neighbors. If a poor region is surrounded by poor regions, the probabilities of moving upward for the periods from 1978 to 1990 and 1990 to 2000 decrease to 0.148 and 0.025 respectively, while they average 0.2 and 0.042 in traditional Markov matrices. It suggests that poor regions are negatively affected when surrounded by other poor regions. Conversely, if a rich region is surrounded by rich neighbors, the probabilities of moving upward for those two sub-periods increase to 1 and 0.991, while they are 0.987 and 0.984 on average in traditional Markov matrices. It suggests rich regions are positively influenced by other rich regions being surrounded. These empirical analyses provide a spatial explanation to "convergence clubs" detected in traditional Markov method.
The Structures Systems of Urban Agglomerations (SSUAs) in China are the spatial and synthetic polymers coupled organically by Urban Agglomerations with different development degrees, grades, political relationship, formative reasons and spatial locations through various flows of substance, power, information and knowledge. Based on the synthetic analysis of the SSUAs at home and abroad, it is found out that world SSUAs are in the process of formation, the functions with different grades for Urban Agglomerations are fabricating profoundly now through new international division of labor and region, and at the same time, although Urban Agglomerations are in the incipient phase as a whole, they are the most vigorous strategic strong point and growth pole with the greatest potential in the economic development framework in the future, and they will dominate the economic development orientation in China. The paper identifies three grades according to the calculating results using of model subject to the index of development degree for Urban Agglomerations in China. The first grade group constitutes Urban Agglomerations on the Yangtze River Delta, Pearl River Delta and of capital Metropolitan Coordinating Region. The second grade consists of 11 Urban Agglomerations in Shandong Peninsula, Chengdu and Wuhan metropolitan coordinating regions. The third grade group is composed of 14 Urban Agglomerations in the central Yunnan Province and the north Tianshan Mountains. Further analyses indicate that there are great differences among the 28 Urban Agglomerations, but such differences are reasonable to some degree. They have showed some characteristics of regional heterogeneities including different development phases, non-equilibrium in overall distribution, regularities in regional heterogeneous pattern, distinct disintegration and heterogeneity in inter-conglomeration. Based on the above analyses, the paper suggests that future studies should focus on the theoretical studies of the multi-dimension, regularity and phase subject of the SSUAs in China, enhance studies on the differences in heterogeneity and competitiveness in the formation and development of the SSUAs and reinforce research on their internationalization, globalization and dynamic monitoring.
This paper extracted urban boundary information in six periods of 1900, 1930, 1954, 1976, 1990 and 2004 by integrating TM and SPOT images, relief maps, history maps and other spatial data of the last 100 years. Based on spatial center of gravity transfer model, fractal model and urban land-population different speed rising model, urban land utilization spatial expansion process and its mechanism for 100 years. The research results show that Changchun urban land area was 5.05 km2 in 1900 and expanded 56.77 times of its area from 1900 to 2004. Changchun urban land area expansion is the quickest from 1990 to 2004 with a speed of 7.89 km2 annually. Then the expansion speed was 3.60 km2 every year from 1930 to 1954. The slowest period was from 1900 to 1930 with a speed of 0.41 km2. Changchun urban land utilization fractal character became more and more complicated with edge being filled mostly from 1976 to 1990. During other periods of time urban land utilization mainly expanded along edge area. Changchun urban population increased 87.57 times from 1900 to 2004. Then per capita available urban land area gradually reduced from 1900 to 2004. Based on urban land and population different speed rising model, the relationship between Changchun urban land and population was analyzed. The result indicated that Changchun urban land and population different speed rising models change irregularly because Changchun urban development and construction was affected by Japanese and Russia empire invasions before 1948.
Based on the data of official network bulletin, statistics and the field survey conducted in 2004, this paper analyzed the relation between the changes of the migrants in their original hometowns, education level, age structure, employment and the economic development in Beijing and the regional differentiation of the distribution of the migrants with different hometowns, age, education, income, work, housing situation and such in the three-circled areas of Beijing which include the central area, near suburbs and outer suburbs since 1997. This paper holds: (1) the concentration trend of the migrants in the near suburb belt is closely connected with the rapid development and the tendency to be the new development center of Beijing in the belt. (2) The employment structure of those migrants is highly corresponding to the industrial structure of Beijing. (3) One of the important employment characteristics of the group is that its employment structure is closer to that of the urban population, but rather different from that of rural population in Beijing. (4) Though their employment ratio in the tertiary industry is much closer to that of the local urban population, their employment ratio in the so-called white-collar sectors in the tertiary industry is far more below that of the local urban population, which is about one eighth in 1997 and one fifth in 2002. (5) They are still constrained by the factors as their lower education level, their personal quality, technique level and cultural background, and they are unable to enter at present into the highly developed and high quality required sectors to work, which have high added value and may give them high income. (6) The regional distribution characteristics of the migrants in the city proper are quite different form that of the migrants in the near and outer suburbs in age, duration in Beijing, education, employment, income, housing and desire for future migrating.
