Based on land ecological classification in the source regions of the Yangtze and Yellow rivers and field investigation, the two phases of TM remote sensing data obtained in 1986 and 2000 were compared. From spatial distribution pattern variations and type transformation trend, the spatial changes and evolutional patterns of land ecosystem in the source regions of the two rivers were analyzed in this paper using the analytical method of landscape ecological spatial patterns. Results show that high-frigid grasslands degraded obviously by 15.82% and 5.15% for cold steppe and cold meadow areas respectively, and high-frigid swamp meadow area decreased by 24.36%. Lake water area was reduced by 7.5%, especially the lakes in the source region of the Yangtze River. Land desertification is developing rapidly and desertified land area has increased by 17.11% on an average.Desertified land in the source region of the Yellow River is expanding at an annual rate of 1.83%. Analysis of the evolutional pattern of land ecotypes shows that the general tendencies of spatial evolution in the regions are coverage reduction and desertification of high-frigid steppe, cover reduction and steppification of high-frigid meadows, and desiccation of swamp meadow. As a result, land ecological spatial distribution pattern in the region has changed and eco-environment is continually worsening.
Based on examinations of the culture characters from late Paleolithic age to late Neolithic age by math method, we discover three times large-scale ancients remove in history. First, about 50 KaBP-10 KaBP, the southern ancients removed to the north of Tibet. Second, about 6 KaBP-3.6 KaBP, the northern ancients removed to east of Tibet. Third, about 3 KaBP-2.2 KaBP, the eastern ancients removed to the middle part of Tibet. The remove laid the foundation for the formation of later culture in Tibet. We also discover that the climate is the main cause of the ancients' remove. The consequence of the great remove is a fusion of different cultures which produced a new culture, because the migrants served as the crowed is only carrier of the information about the technique and the experience before the appearance of the writing system. Thus the information is expressed by population. We give the method to study the culture remove and change by determining a more similar culture with the given culture via the similar coefficient. Finally, whether or not paleoanthropologic character, especially, the features of are identical between the two cultures.
Based on Universal Soil Loss Equation and methods of mathematics model and GIS analysis, we classified influence of precipitation, soil, topography and vegetation upon sensitivity of soil erosion into five different degrees. As a result, assessment map of each factor was finished. We also drew integrated assessment map of sensitivity of soil erosion by overlapping function with Arcinfo. Furthermore, we analyzed distribution characteristics and spatial difference of sensitivity of soil erosion in Tibet under special plateau environment. According to sensitivity degree, priority erosion control areas were confirmed so as to provide scientific basis for departments of water conservancy, traffic management and agriculture which could make scientific and reasonable decisions.
Quantitatively determining the provenance of dune sand is one of the problems necessarily and urgently to be solved in geomorphic and desertification research. Based on the granulometric data of sand materials from the Hulun Buir Sandy Land, the stepwise discriminant analysis (SDA) technique for two groups is employed to select the principal factors determining the differences between surface loose sediments. The extent of similarity between two statistical populations can be described quantitatively by three factors such as the number of principal variables, Mahalanobis distance D2 and confidence level ?琢 for F-test. Results reveal that: 1) aeolian dune sand in the region is mainly derived from Hailar Formation (Q3), while fluvial and palaeosol sand also supply partially source sand for dunes; and 2) in the broad valley in the vicinity of Cuogang Town and west of it, the lower reaches of Hailar River, fluvial sand can naturally become principal supplier for dune sand.
The land desertification in Xinjiang was monitored and analysed on the basis of RS and GIS. The method for drawing samples was used for obtaining the desertification condition throughout Xinjiang and interpreting satellite data in combination with ground investigations. The PCI software has been used to deal with remote sensing data such as image enhancement, classification, auto-classification and so on. Meanwhile the interpretation symbols about desertification type and land type were identified based on ground investigations. According to interpretation symbol, the computer processing and disposition have been used to explain investigation factors. The result was imported with the form of VFP database table, and the attributive database was established. By integrating attributive database, the geographic information data were obtained by using ARC/INFO software, statistical and calculated data have been summarized for the present situation of desertification of Xinjiang. According to the monitoring result, Xinjiang is a widely desertified region, in which desertified area occupies 77.08% of the whole monitored area. For the desertified land type: the desertified farmland is 1.92%; desertified woodland is 4%; desertified grassland is 45%; and unused land is 49%. For the desertification degree: non-desertification is 22.92%; weak desertification is 5.69%; moderate desertification is 16.58%; serious desertification is 33.19%; and extremely serious desertification is 21.61%. Based on the main factors of desertification, wind-erosion desertification is 58.23%; water-erosion desertification is 8.69%; saltation-desertification is 6.52%; and freezing-thawing desertification is 3.64%.
Sandy desertification is a major kind of land desertification in the world. According to our research and practice on land degradation in northern China for nearly 30 years, we define the sandy desertification is land degradation mainly resulted from the human impacts through wind erosion in the arid, semiarid and sub-humid regions in northern China. The results of monitoring, based on remote sensing and GIS, show that the total area of sandy desertified land was 38.57×104 km2 in 2000, of which the slight and potential lands were 13.93×104 km2, moderate land was 9.977×104 km2, severe and very severe lands were 7.909×104 km2 and 6.756×104 km2. The sandy desertified land is mainly distributes in the interlacing agro-pastoral region, grassland, semiarid rainfed cropland and oasis irrigated cropland regions. To compare the analytical results of remote sensing data in the late 1950s, 1975, 1987 and 2000, we summarize that the development of sandy desertified land in northern China had been accelerated for the last 5 decades, as its annual expanded rate was 1 560 km2 during the late 1950s and 1975, 2 100 km2 between 1975 and 1987 and 3 600 km2 from 1987 to 2000. The whole situation of sandy desertification comes to depravation and only part of it had been controlled. While most parts of regions had been suffered continually by the spread of sandy desertified land, some desertified areas in the interlacing agro-pastoral region and rainfed cropland region had been improved to be avail farmland and grassland resulted from favorable policy and patterns of landuse, which proved that the process of sandy desertified land could be managed when the fashion and intension of landuse come to be reasonable.
Through an analysis of urban-regional statistics, while reviewing its basic characteristics, the four major functions of the Lanzhou-Xining-Yinchuan urban corridor are discussed: as strategic location and development pole in China's hinterland; as nexus linking between China's eastern and western parts, between China and Inner Asian and European countries; as site of energy and petrochemical production and major passageway in protecting national resource security; and as major construction zone in protecting national ecology security. Focusing on the problems of sectoral restructuring, marketisation, openness of economy, this article highlights the future trend of development and strategic options: to speed up transport construction in the urban corridor; to transform factor endowments into actual economic advantage; to create subregional environment conducive to investment and open society; and to focus on education, technology and ecological construction.
Using data from Zhifanggou valley of fragile loess hilly-gully region, this paper studied the feature of primary plant productivity, secondary animal productivity, economic productivity of farmers and ecosystem service productivity as well as the relationships among them based on the emergy analysis method. The result showed that the primary productivity of Zhifanggou valley had been improved considerably after twenty years harnessing practices. Consequently, vegetation cover increased to some extent and the great ecosystem services created the base for the formation of the agroecosystem productivity. On the whole, however, the valley was still in the state of lower emergy input, lower coupling degree and lower energy efficiency. They are mainly reflected in the non-obvious coupling effect among various systems and the existence of the lower emergy value of the secondary aminal production. The emergy of primary production could not be transformed into the emergy of the animal production which meant that the capability of transformation from the primary production to the secondary production was lower. The irrational planting structure led to the lower capability of transformation from potential economic value of product emergy to actual economic income of the farmers. So, it is really necessary to adjust the industrial structure and allocation in order to promote the inversion among the agroecosystem productivities.
Climate in the agri-pasture transition zone, northern China is analyzed on the basis of daily mean temperature and precipitation observations for 31 stations during 1956-2001. Analysis season for precipitation is May-September, and for temperature is the hottest three months, i.e., June through August. Heavy rain events, defined as those with daily precipitation equal to or larger than 50 mm, show no significant secular trend. A jump-like change, however, is found occurring in about 1980. For the period 1980-1993, the frequency of heavy rain events is significantly lower than the previous periods. Simultaneously, the occurring time of heavy rains expanded, commencing about one month early and ending one month later. Long dry spells are defined as those with longer than 10 days without rainfall. The frequency of long dry spells displays a significant (at 99% confidence level) trend at the value of +8.3%/10a. That may be one of the major causes for the frequent droughts emerging over northern China during the last decades. The frequency of hot days is increasing, while the low temperatures are significantly decreasing.
To fu1ly reveal the water abnormity and its formative causes in Dongting Lake during recent decades, this paper takes Dongting Lake as a big system. Researches through a variety of methods such as the relation between water-level and runoff show: (1) The runoff on the same water-level reduces 1200 m3/s-2800 m3/s in the lower reaches of the four rivers flowing into the lake, the water-level with the same runoff runs up 0.49 m-1.28 m; (2) The dividing-water ratios of the three bayous of the Jingjiang River reduces by 19.2%, and the dividing-sand ratios 25.1%; (3) Great changes have taken place in the relation between water-level and runoff in the main flooding roads such as Li River, Songzi and southern Dongting Lake etc.; (4) The natural regulation and storage capacity fall off by 40%, the water-level with the same runoff at the bayous drives up 1.80 m-2.50 m; (5) The relation between lake and protective embankment is often at hazard during the period of July and August. The main reason is that the filling-up of mud-sand arises a vicious circle which leads to environmental function changes of the lake system, and the water-sand adjustment from the three curve-cuttings on the lower reaches of Jingjiang River accelerates the change process.
International Hydrological Program (IHP) is the exhibiting platform of the international water resource research; its advance is the integral record and embodiment of the development of worldwide water resource research. The study history and progress regime of IHP show that the water resource research has been changed from the single subject study to integral research with multi-subject. With the increase of the social factors, water resource research has been a systematic research project. Chinese water resource research advance lags behind a little to the international water resource research development and has the better development trend with respect to water resource research. Chinese water resource research system (CWRRS) has the structure with circle-layers. The process and mechanism of water cycle in the changing environment are at the core of the CWRRS and are the inner circle-layer. The sustaining and safeguard system of water resource based on the eco-hydrological process is the second inner circle-layer. The water resource allocation system based on the natural-artificial two-term mode, the water saving system based on physical, chemical, biological and information techniques, and the prompting system of efficient water resource utilization based on the market mechanism are formed in the third circle-layer. Based on the above three circle-layers research, the synthetical decision and integral management system on water resource research based on the modern information techniques and management techniques and the water education and training system based on the modern media techniques make up of the outset circle-layer.
The detailed analysis of suspended sediment concentration variations over a year period is presented from eight observation stations within the Yangtze River estuary and its adjacent waters, combined with hydrodynamic regime of the estuary. Spatially, the suspended sediment concentration from Xuliujing downward to Hangzhou Bay increases constantly, and the suspended sediment in the inner estuary shows higher concentration during summer than during winter, while in the outer estuary it shows higher concentration during winter than during summer, and the magnitude is greater in the outer estuary than in the inner estuary, and greater in the Hangzhou Bay than in the Yangtze Estuary. The sediments from the Yangtze River are resuspended due to marine dynamic actions including tidal current and wind wave. Temporally, the suspended sediment concentrations show a neap-spring tidal cycle and seasonal fluctuations. Furthermore, it is concluded that wind waves and tidal currents are the two predominant factors related to sediment resuspension and control of the changes of suspended sediment concentration, in which tidal currents control the neap-spring tidal cycle, and wind waves control the seasonal fluctuation. The river water discharge and marine dynamics control spatial distribution of suspended sediment concentrations.
The knowledge about evolution modes of water resources is important not only for hydrologists but also for water resources managers, especially for the Yellow River, which is suffering from water resources deficit. In this paper, analysis on evolution modes of water resources in the Yellow River Basin was carried out with the EMD-Hilbert Transform method based on precipitation and annual runoff of the past 50 years in the Huayuankou Station. The results have shown that the change of precipitation can be described by four intrinsic mode functions (IMF) and a decreasing tendency function, while the runoff series have been decomposed to 3 IMFs and also a decreasing tendency function. Comparing the evolution modes of annual runoff with that of annual precipitation, we have found that they were not changing in-phase, though there were some correlations between them. In the time scale, the change of runoff appeared to lag behind that of precipitation, which to some extent may due to the adjustment capacity of the underlying surface. In addition, according to periodicity of the IMFs, it can be inferred that the change of water resources in the Yellow River Basin may be due to QBO and ENSO events, which has called for further research work.
Based on the long-term serial NOAA/NDVI dataset during 1983-1999 and SPOT/VGT dataset in 2001, the land use/cover change information in the 13 provinces of northern China was extracted based on the analysis of the cultivated landscape characteristics at first, then the effects of human activities on cultivated land process were explored by GIS and the driving forces of cultivated land change were investigated. The conclusions can be drawn as follows: (1) The constant increase of weak ecological function land as desert and cultivated land and the decrease of the ecological function land of forest and shrub were the main characteristics of the land use/cover change in the 13 provinces of northern China from 1983 to 1999, which showed the effects on the ecological adjustment function. However, such situations were changed to some extent in the 2000s because of the ecological construction policy of the government. (2) From 1983 to 2001, the Baycenter of cultivated land had the trend to move from northeast to southwest with the topography and transportation situations showing the obvious effect on the cultivated land distribution. It is found that the cultivated land use intensity decreased obviously with the increase of distance from the main communication arteries. (3) The improvement of the people's living standard is closely related with the cultivated land change. The structural adjustment in the agricultural land caused by economic development and the improvement of the people's living standard is the important factor affecting the cultivated land change in northern China from 1983 to 2001.
Land use data integrates lots of information of factors affecting population distribution. It is the nature of land, the household responsibility system, the household registration system, and the production mode of agriculture in China that establish a close spatial relation between land use and population distribution. According to the idea of modeling separately by town and country, by ecological zones along with the population of counties as restrictive conditions, we build the following model based on land use to simulate the population density in 1 km square grid-cells of China: POPij = Pir×Vjr/■Vjr + Piu×Vju/■Vju. Linear weighted model is used to calculate rural population indices. It firstly picks out the indicators for the model which are correlated positively and remarkably with the population of counties in each of the 12 ecological regions, then stepwise regression is introduced to calculate the indices; and finally the weighted coefficients of various indices are determined in combination with the productivity of land and the relations between habitation and variant land. For the urban population indices, a power exponential model based on the scale of town and the distance from the center of town, rooted in distance decay function, is built as Vij = Aj×lnAi×exp(-1.9874rj1.2Ai-0.6). The outcome of the simulation shows that 94.58% of the population inhabit in the southeast of Hu Huanyong population line, and its density is 21 times as that of the northwest. In the east, population is centralized in four regions and one zone. They are Huang-Huai-Hai plain, Sichuan basin, plains of the middle and lower Yangtze River, Northeast China plain and the zone of 100 km from coast. Moreover, a "points-axis" pattern of population distribution is discovered on the southeast coast. Because this paper has fully recognized the relation between land use and the population distribution, the outcome of the simulation proves to be highly credible. Compared with other models, this method is more efficient.
In this paper, the indexes and models are used to measure the accessibility of transport network, such as total transport distance Di and accessibility coefficient. On the basis of "The Shortest Route Model", the evolution of railway network, changes of the spatial structure in accessibility, the relationship between railway network distribution and spatial economic growth in the past several hundred years in China are analyzed. The results show that the evolution of railway network in China experienced 4 stages, i.e., initial stage, constructing stage, extending stage and optimizing stage, but the speed of spatial expanding is relatively slow. One hundred years' construction of railway leads to "time-space convergence". The spatial structure of accessibility displays "different circles with one core", and radiates from North China to the surroundings. The area, higher than the national average level in accessibility, expands from North China to East China and Central China, and the center of accessibility moved from Tianjin to Zhengzhou gradually.
The mountainous economic development depends on the macro-scale backgrounds of the whole country as well as the laws of regional economic developmental stages. In each stage, regional economic development has distinctly industrial structures and economic driving forces. In this paper, based on analysis of regional developmental mechanism, the authors propose a temporal & spatial conception model (T = S model), which reveals regional evolution is an integration of fluctuation in temporal dimension and disparity in spatial dimension. By using the T = S model, four conclusions have been drawn: First, both the phase and states of mountainous economic development of China in the next 5, 10 and 20 years have been simulated. Second, the authors predict that per capita GDP of mountainous regions will reach 8000 yuan RMB in 2005, and about 12000 yuan RMB in 2010. Third, the shift of mountainous economic development stage was scheduled. Finally, some suggestions concerning policies relative to the shifting conditions were put forward.
As a key driving force of modern economy, the process of man-land relationship in eastern China has a decisive influence on sustainable development of both the whole country and the region itself. This paper is aiming at evaluating the general pattern of man-land relationship in eastern China through a cross-factor model, which refers to the interrelationship between regional resource-environment base (arable land, waters, minerals, forestry, and energy resources) and human activities (population growth and GDP increase). The findings of this paper could be concluded as the following: first, because of highly convergent human activities, a much more pressure on the man-land relationship of eastern China during the last 20 years has been proved when compared with both central China and western China; secondly, economic activity, rather than population growth, had a decisive influence on the highly intensified man-land relationship of eastern China; thirdly, in order to release the growing pressure on the man-land relationship of eastern China, it could be useful to reinforce the resource-environment base of eastern China itself by opening-up the region widely on the one hand, and improve the efficiency of resource-use through speeding up regional economic structure deeply on the other.
