In this paper, we discussed the international research response to climate change, climate change and the economic impact of climate protection, and suggested that new research should focus on climate protection modeling and simulation. This article evaluated 6 models of the emissions scenarios used to rely on specialized report features in Fourth Assessment Report of IPCC, and pointed out the IPCC's SRES models ignore the endogenous technological progress and international GDP spillover, and attention focused on the economic effects of the passive response to climate change, so that we need to develop a proactive model now. The article also discussed the research in climate protection deficiencies in China, including reliance on foreign software and statistical models, the lack of dynamics simulation, stressed that the urgent task is to develop a new model of macroeconomic dynamics, nonlinear CGE model and simulation model based on agent, and made China-program about the global climate protection. Finally the author introduced the LRICE model framework which was developed by Wang, Wu Jing and others. The model, characterized by technological advances in learning by doing, reflects the fact that developing countries will reduce carbon dioxide emissions through technological progress, which is closer to the real world.
El Nino has a great influence on the global climate and it also influences the climate of Guangdong province. Based on the systematic classification of El Nino disaster, this paper studies the correlation between El Nino and drought disaster in Guangdong Province in recent 60 years by means of X2 inspection and condition probability inspection. Then the paper draws the conclusion that drought disaster of Guangdong Province has a close relationship with El Nino events. Out of 23 drought events, 17 times relate with El Nino events. In addition, the paper examines the influence on the drought disaster in Guangdong Province caused by different kinds of El Nino disasters. The result indicated that there is a certain relationship between the intensity, season and duration of El Nino occurrence and the droughts in Guangdong. Generally medium and strong El Nino events lead to drought in Guangdong Province. The El Nino events in spring and autumn are not prone to drought while those in summer are prone to. Successive El Nino events often lead to occurrence of drought in this region.
It is necessary to discover the response mechanism between tree-ring growth and climate change for climate reconstruction. The response mechanism is diverse in different climatic or environmental contexts, especially for topography or altitude. We developed five tree-ring width chronologies from sites ranging in elevation from 2800 m to 3700 m a.s.l. on the east slope of Gongga Mountains. Characteristics of the chronologies and radial growth have been analyzed. Response function was applied to discuss the relationship between tree-ring widths and the climate factors. The results indicate that rates of radial growth show a trend along with the altitudinal gradients. Climate-growth response analysis revealed that radial growth is mainly controlled by temperature. The radial growth is controlled by July mean temperature at the timberline (3700 m a.s.l.), and by March mean temperature at the 3000 m a.s.l. However, there is no significant correlation between tree-ring width and climatic factors at the 2800 m a.s.l. Compared with the documented climatic records and the fluctuations of Hailuogou Glacier, tree-ring width chronologies imply an indicative power to climate change.
The Yalu River is the boundary river between China and Democratic People's Republic of Korea. The characteristics of detrital minerals in surface sediments in the Yalu River estuary and its adjacent shallow seas were analyzed in this paper. Through discussing on the compositions, distribution and longitudinal variation of detrital minerals in surface sediments, interpreting the sedimentary environment of detrital minerals and the difference of indicative mineral and characteristic index as well as their trace significance, the results indicated that the surface sediments in the Yalu River estuary and its adjacent shallow seas probably came from different material source zones. For the surface sediments in Middle-river-way and the lower reaches of the Yalu River, their longitudinal variation of main detrital minerals is successive. They are similar to the sediment characteristics in the Aihe River in the lower reaches of the Yalu River in material source zones index, stable coefficient and ATi, which indicates that the sediment process in Middle-river-way and modern rivers have a close relationship. Although West-river-way and Middle-river-way are adjacent, the sediments in West-river-way and Shuifeng Reservoir are similar more or less, which indicates that West-river-way is the key river course, remaining the sediment characteristics before the reservoir was built in 1941. That the sediments in West-river-way most came from the shallow seas offers the obvious evidence that the sediments in shallow seas moved to land areas. The characteristic minerals and other indexes in shallow ford of Liaodong are between those of Middle-river-way and West-river-way, which indicates that its material resource most came from the Yalu River, and less came from shallow seas. The degree of influence from shallow seas needs a further study.
The Huaihe River was an independent river directly flowing into the Yellow Sea before 1128. It became a tributary of the Yellow River in 1128~1851. The lower Yellow River channel shifted to north and entered the Bohai Sea in 1855. Actually, the Huaihe River has been a tributary of the Yangtze River since 1851. At present, after going into the Hongze Lake, the Huaihe River water flows into the sea by four routes. By constructing a channel separated from the Hongze Lake along the northern coast of the lake, and deeply excavating the present Huaihe River Channel to Sea and the Huaishu River-Beiliutang River-New Yihe River channels, water would directly flow into the Yellow Sea and no longer to the Yangtze River. An annual 1000×104 t of suspended sediments (increasing by 860×104 t more than present) would deposit on the coast from Lianyungang to the Sheyang River mouth. The coastal erosion from Lianyungang to the Sheyang River mouth would be ended: the northern section would be stable and the southern section would slowly prograde, forming a new Huaihe River delta. Meanwhile, the sediments would not accumulate on the middle Huaihe River channel and Hongze Lake, and would effectively reduce inundation in the middle Huaihe River reaches.
Soil erosion is one of the most serious environmental problems in the world. In Southwest China dominated with carbonate-rocks and karst landscapes, soil erosion and its resultant 'rocky desertification' are also very serious. Studies of sediments of lakes and reservoirs have been used to obtain information on changes in soil erosion through time of catchment by sampling and dating sediment cores, and calculating sediment deposition rates and analyzing them for proxy data such as mineral-magnetics. Mineral magnetism techniques have been widely used in analyses of lake and reservoir sediments to research soil-erosion changes. It has been proved to be a valuable method to investigations on soil erosion occurring in the catchments of lakes and reservoirs. Maigang Reservoir (26°00'50.3″N, 106°17'38.4″E) was built in Ziyun County of Guizhou Province, Southwest China in 1956. It has sub-tropical monsoon humid climate and is located in a carbonate-rock-dominated catchment of 7.5 km2. A 19-cm long sediment-core (MG1-1) was sampled from the reservoir in April, 2008. Some mineral-magnetic parameters including SIRM, ARM, lf, hf, IRM20mT and IRM-100mT were measured and ARM/SIRM, HIRM, IRM-100m T/SIRM and fd were calculated. We inferred soil erosion that occurred during 1960~2007 (47 years) in the drainage basin based on these mineral-magnetic characteristics in combination with the results from analyses of 137Cs, grain-size, TOC and C/N for these sediment samples. Soil erosion generally has some sub-order fluctuations in its changes which presents a pattern "intensive-weak-intensive-weak" in this period. According to the precipitation and land use/land cover change (LUCC) data, the primary causes of soil erosion are deduced. Precipitation has small impact on the changes of soil erosion, but human activities, especially the land use and land cover changes are the main causes for soil erosion in the catchment of Maigang Reservoir.
Based on 5336 typical soil profiles collected during the second national soil survey period, the correlation between topsoil total nitrogen (A horizon) and 11 environmental factors were analyzed and spatial distribution of topsoil nitrogen (TN) at national scale in China was simulated with the combination of multiple regression model and HASM model. Results indicated that, mean absolute error and mean relative error of the predicted value for 350 validation points were 0.67 g·kg-1 and 61.06%; compared with ordinary kriging method, the two errors were reduced by 0.05 g·kg-1 and 17.53% respectively. Besides, simulation result for northwest China, where the density of sample points was much smaller, was much closer to the actual situation. Thus, a combined method of multiple regression model and HASM model, which took the influence of environmental factors into account, can be used as an effective method for simulating spatial distribution of soil properties at a large scale.
In order to find out the concentration of CO2 in the desert area, its influence on the CO2 in the atmosphere and the role that it plays in the global carbon cycle, the research team utilized infrared monitor of CO2 to observe the concentration of CO2 of the 17 drill holes day and night in May 2009 in the highest desert area in Badain Jaran in the world. Results show that the difference of various observation spots' concentration of CO2 in the desert area in Badain Jaran is relatively big. The concentration of CO2 at each observation spot changes from 0.01% to 0.075%, and the concentration of CO2 at night is low but high in the daytime. The diurnal variation of concentration of CO2 in the desert area in Badain Jaran is obvious, and from 7 am to 6 pm, the concentration of CO2 at different depths ranging from 1 m to 5 m presents the regularity that it changes from low to high, and then from high to low. During 24 hours, four turning points are observed in the concentration of CO2, and they appear at 5 am, 11 am, 18 pm and 21 pm. Under the condition of unchanged water content of sand layer, the diurnal variation in temperature is the main reason for the change of the concentration of CO2 in the sand layer, and the diurnal variation in temperature is positively correlated with the diurnal variation of concentration of CO2 in the desert area. The sand layer's concentration of CO2 with higher water content is obviously higher than that with lower water content. Concentration of CO2 above 5 m in the desert area is higher than that above the surface, which indicates that the highest desert area where the CO2 comes from is also the source of CO2 in the atmosphere, and the sand layer's concentration of CO2 is generated from the activities of germs in the naked high large desert area with nasty environment.
This paper investigated the variation trend of annual average NDVI both in the overall Tibetan Plateau and in different eco-geographical regions. The spatial characteristics of the response of NDVI to climatic factors (temperature and precipitation) in different eco-geographical regions were assessed based on a half-month maximum synthesis GIMMS NDVI dataset and climate data from 104 meteorological stations during 1982-2006. The results showed that: (1) The vegetation coverage tended to improve on the whole in the past 25 years, especially in the northeastern and southwestern plateau, and the middle part of the eastern plateau, which belonged to the humid and semi-humid regions. But the vegetation degradation happened in the northern and western plateau, which belonged to semi-arid and arid regions. (2) The correlation between vegetation change and temperature variation was relatively large, which showed that the response of vegetation change to temperature variation was more sensitive than to precipitation. (3) The correlation between vegetation change and temperature and precipitation variations was obviously different in different eco-geographical regions. The greatest correlation was shown in the moderate vegetation cover region, and it gradually weakened from meadows and steppes to coniferous forests. The relevance of desert was the smallest. The correlation between vegetation cover and temperature during growing seasons was consistent with that throughout the year, but was greatly different from the correlation with precipitation that was not significant during growing seasons.
The Dongting Lake Area (DLA), a famous and important commodity grain production base in China, is one of nine industrial belts of the top agricultural products, and belongs to the top grain industrial belt of double-cropping paddy in the Yangtze River Basin. Therefore, the investigations based on the rice productivity of the DLA is vital for the optimization of the land resource allocation, assessment of the paddy field ecosystem, design of agricultural development plan and protection of agricultural eco-environment. According to the meteorological analysis data from 2003 to 2007 and the soil analysis data of the Second National Field Survey, utilizing the stepwise diminishing method of light, temperature, water and soil, a comparative research was carried out to build an appropriate rice potential productivity model for the DLA. Two rice potential productivity models (photosynthesis-temperature potential productivity calculation by step-by-step model and FAO-AEZ model) were investigated, followed by the analysis of the spatial distribution of late rice potential productivity with the assistance of Geographic Information System (GIS). The results showed that the mean simulation value of five years (2003-2007) predicted by a step-by-step model achieved 7808.072 kg/hm2, higher than the observation value (5904 kg/hm2); while the simulation value obtained by FAO-AEZ model was only 5687.45 kg/hm2, even lower than the mean observation value, which is unreasonable for the actuality of DLA. This disclosed that the model based on step-by-step calculation of photosynthesis-temperature potential productivity was appropriate to predict the late rice potential productivity in the study area. At the same time, the research also revealed that the late rice potential productivity in the DLA decreased gradually from northwest to southeast. The regions of Lixian, Anxiang, Hanshou and Linli counties in Changde city contributed high or medium yields, while the low yield areas were mainly distributed in Changsha, Yiyang and Yueyang cities. The late rice potential productivity of the DLA was inadequate, and the low yield area occupied 45% of the total DLA, which exhibited great potential for the improvement of the late rice yield by means of sound tillage control measures, including rational fertilization system and water management.
In recent years, a sharp decrease of water quantity and frequent discontinuous flow happened in the lower Yellow River due to the rapid increase of water consumption in the basin area. This leads to deficiency of suitable water demanded by the ecosystem of the estuarine delta. As a result, fresh water wetlands in the delta are diminishing and facing the danger of disappearance. Basic guarantee of water supply to the Yellow River estuary and eco-water demand for wetland restoration has become a key issue in maintaining the ecosystem of the Yellow River Delta. In this paper, landscape ecological and hydrological models were integrated for the Yellow River Delta wetlands restoration. First, three scenarios at different water depths for the degraded wetlands restoration were designed. For each scenario, the spatio-temporal changes of flooding duration and water table were simulated with the model SOBEK, and average groundwater levels were simulated with the finite-difference groundwater flow model Visual MODFLOW. Then the simulation results were integrated with site conditions and current vegetation types into LEDESS model for modeling the landscape development after 5 years of restoration. Finally, each scenario was evaluated based on its consequences for habitat effects. In this way, choices can be made on what kind of nature type is desired and what is the optimal restoration strategy. The results show that all scenarios can significantly improve the wetland conditions of reed marshes, which are used for many rare and endangered birds like red-crowned crane as important habitats. By comparison, scenario B with the medium water discharge is better than scenarios A and C in reed marsh restoration, but scenario C can also create large area of open water bodies which are crucial for the swan's habitat conservation. However, not all kinds of species benefit from the restoration plans. The study also shows that large areas of tidal flats were encroached by the restored reed marshes. As a result, carrying capacity of the estuarine wetlands in shorebirds such as Saunder's Gull would decrease after restoration. This study demonstrates that a spatial decision support framework that integrates hydrological processes modeling with ecological evaluation at a landscape scale is indispensable to evaluate uncertainty about the effects of restoration plans and policies on different wetland types and the quality of waterfowl habitats.
In recent years, the main function zone planning (MFZP) has become a hot topic for all levels of government and academia. This paper focuses on the MFZP on the urban space dimension, namely the urban Development Spatial Region (DSR), which has been advanced by experts in China. And the city is divided into four major categories of optimized development, key development, restricted development, and prohibited development. Based on the existing theory and research, the paper explores the theoretical model and methodological options of urban DSR, and analyzes DSP from three aspects of constraint of development, guidance of development and intensity of space development. Using the two-dimensional matrix, constraint of development and guidance of development construct the matrix. And then, in combination of the matrix with the intensity of space development, the result of DSR can be obtained. Different kinds of SR imply different applications. In the aspect of empirical research, Nanjing as a study case is applied by the theoretical model and methodological options of the urban DSR. The paper provides the space distribution solutions for Nanjing's development, so as to optimize Nanjing's urban spatial development strategy. And it has some guidance for the development of spatial order, the direction of the expansion of space, industrial layout adjustment, as well as some reference for the relevant research of the main function zone planning in Nanjing.
Based on five investigations of Zhitian Village, Gongyi City, Henan Province, China, the paper classifies the phases and sums up its characteristics and spatial-temporal change of rural industry in a village-level unit. The quantitative study of spatial-temporal change of village industry can be conducted on social physics, such as Refraction Law, Universal Gravitation Law, and Molecular Transition Law. The paper verifies theoretical assumption that the microscopic scale can reflect the larger-scale operating conditions. The results are obtained as follows. (1) High refractive index of industry to agriculture is the main cause for industry-arising in rural industry, and from the point of unit area, rural industry has much better profits compared to agriculture; from the point of unit labor, rural industry substituted other rare factors for labor. (2) With the distance increasing, the decay of Gravity tends to be the main reason for the spread of rural industry. (3) National policies and external economic environment are the main reasons for fluctuations in rural industry. and The former plays a leading role in the earlier period; with the establishment of a market economy, and the latter role has notably improved and gradually became the decisive factor. (4) High refractive index of private enterprises to collective enterprises is the main reason for restructuring. However, the former has a lower endurance than the latter when economic risk comes. (5) Rural industry has characteristic of scale economy. The larger the scale, the higher the refractive index in different sectors and within the same industry. (6) Concentration efficiency is the main reason for clustering of rural enterprises. The cluster has a greater advantage over the convergence over time, and it will be the direction of the rural industrial development. In the early stages of industrial development, enterprise efficiency is increased along with the scale in the power model, but if industrial development enters a faster development stage, it would become a logistic model which could make a self-inhibition to enterprise efficiency.
Rapid progress has made in urban geography in China in the past three decades. How should we look upon urban geography in China at present and in the future? From the perspective of the axiology of the discipline, this paper collects and analyzes the essays of urban geography from five main academic geographic journals, and makes a systematic review on the history and trends of the development of urban geography in China. We have found that the number of the research papers on urban geography in China has increased steadily after the 1980s, and the growth rate has been slowed down up to the 1990s. The development tendency of the research can be summarized as follows: (1) The research of urban geography in China has mainly concentrated on four aspects of urbanization, urban system, urban spatial structure and urban problems. (2) After 2000, research upon point has decreased relatively, while the research on area has increased; Compared to the reduction of research 'of the city', the research 'in the city' has increased. (3) More and more researches focus on urban function and make use of qualitative methods. Problem oriented rather than theory oriented has been the mainstream. The main problem of urban geography is lack of innovation on the angle of theory and analysis. Lots of researches are basically the duplication of the works 20 years ago. The deeper problem can be illustrated as two different factions on the axiology of the discipline, namely, pragmatism and scientism. From the angle of reflection, this paper appeals for a reasonable research orientation of urban geography in China. Research upon problems and theories should be integrated effectively, and we ought to avoid going to the extremes of metaphysics. They are two sides of urban geography, which are complemented for each other and neither can be neglected.
The paper studies the characteristics and regularity in spatio-temporal evolvement of intersection traffic volume of a typical mono-centric expanding city, based on the analysis of the data of 60 intersections in the years of 1980, 1985, 2000 and 2007 of Changchun city. The main conclusions are drawn as follows: (1) the spatial distribution and evolution of population flow and vehicle flow in the main intersections show a typical mono-centric circular expansion and axial agglomeration, namely center radial of circle-type characteristics, indicating that the traffic volume and road utilization rate of the central city are higher, while those of edge area is relatively low; (2) there are differences between the spatio-temporal evolvement of population flow and vehicle flow in the main intersections. Population flow shows a smaller and slower growth rate, with great and little change of variation coefficients in the past years, which is characterized by central agglomeration. To the contrary, the vehicle flow exhibits a larger and faster growth rate, and the coefficient of variation is smaller than that of population flow and has great changes. The traffic pattern shows the obvious point-axis centralized characteristics along the main roads based on central agglomeration; (3) Although population flow and vehicle flow in the main road intersections had great changes from 1980 to 2007, the spatio-temporal pattern of the traffic volume did not witness a fundamental change, which indicates that the spatial structure of mono-centric expanding city exerted a great influence on the spatial distribution of traffic volume.
The linguistic meaning of "imagination" in geographical imagination can date back to the classic Greece. It is gradually permeated into geographical discipline from philosophy, psychology, literature, arts and sociology etc. Sociological imagination is the agent to directly stimulate geographical imagination. The application range of geographical imagination is limited in present foreign area, past native area and past foreign area. The study on geographical imagination consists of four parts: geographic reality, geographic imagination, geographical imagination and imagined geography, which are respectively four philosophical sectors: phenomenon, mental perception, recognition and description. Of geographical imagination, the term "imagination" has multi-meanings such as thought, analysis, inquiry, critique, discovery, ideas, vision, design, conceit, etc. which is the general term of imagination (imaginary, imaginative), imagine (imagining, imagined), image and imagery. In the aspects of the theory and method, "geographical imagination" includes the methods of historical narration analysis in traditional geography, scientific positivism in modern geography, and humanism in contemporary geography. What is known as the term "imagination" is "study" or "research". What is known as "geographical imagination" is really geographical research combined with scientific enlightenment in recent antiquity, scientific positivism in modern times, and humanity concerning in post-modern times.
