Urban agglomerations are an inevitable outcome of China’s new national industrialization and urbanization reaching relatively advanced stages of development over the past 30 years. In the early 2000s, urban agglomerations became new geographical units for participating in global competition and the international division of labor, and China has spent the past decade promoting them as the main spaces for pushing forward its new form of urbanization. The convening of the first Central Work Conference on Urbanization and the National New-type Urbanization Plan (2014-2020) further defined the status of urban agglomerations as the main players in promoting China’s new type of national urbanization. Nevertheless, urban agglomerations remain a weak link in Chinese academia and are in urgent need of study. Only 19 articles on the theme of urban agglomerations were published in the journal Acta Geographica Sinica between 1934 and 2013, accounting for only 0.55% of all articles written during that period. Not only are there very few, they have also all been published within a relatively short period of time, with the first having been published only 10 years ago. The studies are also concentrated among only a few authors and institutions, and research is aimed at national requirements but is rather divergent. Even so, some studies on urban agglomerations have played a leading role and made important contributions to dictating the overall formation of urban agglomerations nationwide. Specifically, a proposed spatial pattern for urban agglomerations formed the basic framework for the spatial structure of China’s urban agglomerations and guided the government to make urban agglomerations the main urban pattern when promoting the new type of urbanization; proposed standards and technologies for identifying the spatial dimensions of urban agglomerations played an important role in defining the scope of national urban agglomerations; a series of studies in the area of urban agglomerations spurred more in-depth and practical studies in the field; and studies on issues related to the formation and growth of urban agglomerations provided warnings on the future selection and development of urban agglomerations. Taking the progress and results of these studies as a foundation, the foci of selecting and developing urban agglomerations in China are as follows: to be problem-oriented and profoundly reflect on and review new problems exposed in the selection and development of urban agglomerations; to concentrate on urban agglomerations and lay importance on the formation of a new “5+9+6” spatial structure for China’s urban agglomerations; to rely on urban agglomerations and promote the formation of a new pattern of national urbanization along the main axes highlighted by urban agglomerations; to be guided by national strategic demand and continue to deepen understanding of major scientific issues in the course of the formation and development of urban agglomerations, including studying the resource and environmental effects of high-density urban agglomerations, scientifically examining resource and environmental carrying capacities of high-density urban agglomerations, creating new management systems and government coordination mechanisms for the formation and development of urban agglomerations, studying the establishment of public finance systems and public finance reserve mechanisms for urban agglomerations, and studying and formulating technical specifications for urban agglomeration planning and standards for delineating urban agglomeration boundaries.

The Yangtze delta’s response to accelerating river damming and irrigation is a topic of global concern. This research analyzed the general erosion-accretion of the submerged delta front, the spatio-temporal changing pattern in different sub-regions, the geomorphological changes in typical cross-sections, and the geomorphological causes of the four main sub-regions (the eastern tidal wetland of Chongming-CM, the Hengsha shoal-HS, the Jiuduansha wetland-JDS, and the eastern tidal wetland of Nanhui-NH). Data sources include topographic data measured at high-resolution, sediment load at Datong Station, and the corresponding estuary construction information. Major findings are: (1) in general, the study area had slightly eroded (the erosion area ratio was 51.83% and the accretion area ratio was 48.17%) from 1982 to 2010, and it had experienced a shift of “erosion-accretion- erosion”. The spatio-temporal change of geomorphology was also significant in the eight sub-regions, excluding constant erosion in the North Channel; (2) evolution in eastern and northern CM and HS, northern JDS, and the region within the 5 m isobath of NH was dominated by vertical deposition, which was the opposite of that in southern CM and HS, and the region within the 5 m isobath of eastern and southern JDS; (3) on the whole, the encompassed surface areas (ESAs) of the 2 m and 5 m isobaths kept increasing, and the annual growth rates reached 10.42 km²/yr and 7.99 km²/yr respectively during 1982-2010 (however, four sub-regions exhibited disagreements), and in the whole region and all sub-regions, the ESA of the 10 m isobath decreased, while the ESA of the 15 m isobath changed slightly during the period and remained stable; (4) being less influenced by the estuarine engineering, CM was the only sub-region where the ESA of the isobath decreased in accordance with the decline of the sediment load. Major conclusions are that estuarine engineering projects play an increasingly important role in affecting the submerged delta against the macro-background of the reduction of sediment load, the change of ESA and the distribution of isobaths. Along with the accelerating construction of the Shanghai International Shipping Centre and reclamation project, the geomorphological evolution of the submerged delta will become more complex and thus deserves frequent monitoring in the future.

Based on field-survey hydrological series in the Dongting Lake watershed from 1951 to 2011, the variations of lakebed sediment siltation/erosion (S/E) regimes of the Dongting Lake after the operation of the Three Gorges Reservoir (TGR) were analyzed. Significantly positive correlations were found between the flow rate from Zhicheng and the Three Outlets (r²=0.859, p<0.0001), and between the flow rate and sediment delivery rate at the Three Outlets (r²=0.895, p<0.0001). This indicated that the flow rate and sediment delivery rate at the Three Outlets were largely determined by the flow rate from the upstream Yangtze River. Sediment deposition amount in the Dongting Lake basin dropped from +4796.4×10⁴ t during the period before the operation of TGR (1999-2002) to +684.1×10⁴ t, +449.8×10⁴ t and -559.6×10⁴ t during the impoundment Phases I, II and III of TGR. The S/E regimes changed from a siltation-dominant to an erosion-dominant state under the pre-discharge, water-storage and water-supplement dispatch over the impoundment from Phase I to III. The sediment deposition amount decreased dramatically under the flood-storage dispatch over the impoundment Phase I to III. The estimated annual mean flow rate, sediment delivery rate and sediment concentration thresholds were respectively 970.81 m³/s, 466.82 kg/s and 0.481 kg/m³ for the upstream Three Outlets to maintain an erosion-dominant state in the downstream linked the Dongting Lake.

The impact of reservoirs on downstream river channel change has been a scientific issue in fluvial geomorphology during the last few decades. However, it is still a difficult issue as to how to express quantitatively the channel adjustment in the Inner Mongolian reach of the Yellow River induced by the joint operation of upstream reservoirs. Based on the shape parameters of channel cross-sections at four gauging stations in this river reach over a flooding season in two periods, 1978-1982 and 2008-2012, the present work investigated the channel changes in terms of shape parameter change rate under the same controlling water level in each flooding season at the channel cross-sections. Results showed that most of the change rates of the parameters evidently increased over a flooding season in both periods. However, the change rate of each parameter at the cross-sections decreased evidently in the latter period, compared with the former period. At the same time, the distribution pattern of the change rate of the shape parameters along the cross-sections thus changed from a convex curve in the former period to an S-shaped curve in the latter period. The obvious decrease of the change rates is related to the joint operation of the Liujiaxia and Longyangxia reservoirs. The reservoirs stored a large volume of water and decreased the peak discharge and maximum velocity in the flooding season; as a result, the erosion ability of the flood decreased accordingly. With the joint operation of the large reservoirs, the Inner Mongolian channel shrunk markedly. Therefore, the channel will present the possibility of an extreme flood in the future. Consequently, it is reasonable to adjust the function of the reservoirs in future. The total water and sediment discharges and the peak discharge in flooding seasons should be effectively controlled. Continuous shrinkage of the channel can thus be avoided and it can be ready for a potential extreme flood.

The formation of Danxia landscapes is too slow to be observed in our life time and the paleoclimates in which Danxia landscapes developed are significantly different from the present. Thus, this study adopted experimental approaches to examine the lithological and paleoclimatic control on the formation of various landscape morphologies in the Mt. Danxiashan, South China. A total of 122 rock samples were collected from a range of Danxia landscape morphologies such as white spots, small and large through caves, honeycomb caves, horizontal grooves, natural bridges, stone pillars, and squama stones. Analyses of the collected samples were conducted in different kinds of experiments, including uniaxial mechanical strength testing; rock resistance against sulfuric acid erosion, freezing, and thawing; X-ray fluorescence spectrometry (XRF) analysis; inductively coupled plasma mass spectrometry (ICP-MS) analysis; and identification analysis under a polarizing microscope. The results indicated that the formation of the various Danxia landscape morphologies could result from one or more of the following processes: differential erosion due to lithological difference, chemical dissolution and recrystallization, freezing and thawing actions, acid corrosion, weathering, lateral erosion of river flows, and tectonic uplifts. Water erosion in humid monsoon climate and the alternations of intensive freezing and thawing actions in the Quaternary glacial stages and the interglacial stages could have had great influences on the formation of Danxia landscape topographies.

Permafrost degradation triggered by a warming climate induces significant changes in soil conditions, and further contributes to apparent impacts on vegetation. However, much less is known regarding the difference in net primary productivity (NPP) and the relationships between NPP and warming temperature among different vegetation types and various types of permafrost zone on the Tibetan Plateau. Consequently, remotely sensed land surface temperature (LST) and NPP from the MODIS platform were used to investigate the response of vegetation NPP to warming climate, and the correlations were scaled up for the study region. Our results indicated a notable increase of NPP from west to east, and significantly increased annual NPP along with the increased LST from 2000 to 2010 in the permafrost zone of the Tibetan Plateau. Meanwhile, the increased NPP for various vegetation types and in different types of permafrost zone with relation to warming temperature was revealed. NPP in the continuous permafrost zone had the greatest sensitivity to the changing LST, and forest NPP presented the most obvious response. Positive correlations between NPP and LST at various scales indicated the enhanced effects of warming LST on vegetation carbon sequestration in the permafrost zone of the Tibetan Plateau. In view of the notable response of NPP to warming temperature on this plateau, remote sensing needs to be further employed to reveal the status of permafrost degradation and its related effects on vegetation.

People’s decisions of residential mobility in housing market and decisions of job change in labor market play an essential role in the formation and dynamics of urban spatial structure. This paper investigates the relationship between residential relocation and job change and its heterogeneity using a large-scale survey of residential living satisfaction and preferences in Beijing. Several conclusions are drawn as follows: 1) People’s decisions of residential mobility are significantly positively correlated with their decisions of job change, indicating that these two-dimensional decisions are in fact a correlated decision process rather than two independent decision processes. 2) There is heterogeneity in the correlated decisions of residential mobility and job change. More specifically, the interrelationship between the decisions of residential mobility and job change among people without Beijing hukou, renters and single-worker households is more intensive than people with Beijing hukou, homeowners and multi-worker households. In addition, there is heterogeneity in the determinants of residential relocation and job change between groups with different types of housing tenure, household registration status and family employment structure. 3) For renters, commuting time can significantly increase the probability of residential relocation, which indicates that residents of different socioeconomic attributes have very different responses to commuting time costs.

Research has shown that there has been a significant change in the quantitative relationship between urbanization and economic development over the past 50 years. As a result of this change, the Chenery model is no longer capable of performing a comparative analysis of these parameters. We carried out a regression analysis of the normal form of the relation between urbanization and economic development on the basis of the Chenery model. We used empirical data from 149 countries and regions from 1990 to 2009 and adopted the double logarithmic model, introducing a time series variable for urbanization. From 1990 to 2009, with a per capita gross national income remaining between USD 1000 and 10,000, the urbanization rate changed from 17.78 to 60.36% and the relational matching data changed accordingly, although the upper limit of the rate of urbanization remained at about 75%. Urbanization in countries with a smaller population size was more affected by economic development than urbanization in countries with large and medium sized populations.

Changes in rice production in Southern China are crucial to national food security. This study employed Landsat images to map the distributions of paddy rice-cropping systems in Southern China in 1990 and 2015. The impact of rice multiple cropping index changes on grain production capacity was then evaluated. Three important results were obtained for the 1990 to 2015 study period. First, the multiple cropping index for rice decreased from 148.3% to 129.3%, and 253.16×10 ⁴ ha of land area was converted from double-cropping to single-cropping rice, termed “double to single”. The area with the most dramatic changes is in the Middle-Lower Yangtze Plain. The rice-cropping system distribution in Southern China showed a change from north to south with double-cropping rice shrinking and single-cropping rice expanding. Second, the “double to single” conversion led to a reduction of 6.1% and 2.6% in rice and grain production, respectively. Hunan and Jiangxi Provinces, located in the main rice producing areas, and Zhejiang, which has shown better economic development, exhibited large reductions in rice production due to the “double to single” conversion, all exceeding 13%. Third, the grain production capacity of converted “double to single” paddy fields is equivalent to that of 223.3 × 10 ⁴ ha of newly reclaimed cultivated land, which is 54% of the total newly cultivated land reclaimed through the 2001-2015 land consolidation project. It is also 1.7 times the target goal for newly cultivated land in the national land consolidation plan for 2016-2020. Making full use of the converted “double to single” paddy fields can save 167.44 billion yuan in newly reclaimed cultivated land costs. Therefore, instead of pursuing low-quality new arable land, it is better to make full use of the existing high-quality arable land. Based on these results, the government should change the assessment method for cultivated land balance, and incorporate the sown area increased by improving the multiple cropping index into the cultivated land compensation indicator.

Land use patterns arise from interactive processes between the physical environment and anthropogenic activities. While land use patterns and the associated explanatory variables have often been analyzed on the large scale, this study aims to determine the most important variables for explaining land use patterns in the 50 km2 catchment of the Kielstau, Germany, which is dominated by agricultural land use. A set of spatially distributed variables including topography, soil properties, socioeconomic variables, and landscape indices are exploited to set up logistic regression models for the land use map of 2017 with detailed agricultural classes. Spatial validation indicates a reasonable performance as the relative operating characteristic (ROC) ranges between 0.73 and 0.97 for all land use classes except for corn (ROC = 0.68). The robustness of the models in time is confirmed by the temporal validation for which the ROC values are on the same level (maximum deviation 0.1). Non-agricultural land use is generally better explained than agricultural land use. The most important variables are the share of drained area, distance to protected areas, population density, and patch fractal dimension. These variables can either be linked to agriculture or the river course of the Kielstau.

The ratio of transpiration to evapotranspiration (T/ET) is a key parameter for quantifying water use efficiency of ecosystems and understanding the interaction between ecosystem carbon uptake and water cycling in the context of global change. The estimation of T/ET has been paid increasing attention from the scientific community in recent years globally. In this paper, we used the Priestly-Taylor Jet Propulsion Laboratory Model (PT-JPL) driven by regional remote sensing data and gridded meteorological data, to simulate the T/ET in forest ecosystems along the North-South Transect of East China (NSTEC) during 2001-2010, and to analyze the spatial distribution and temporal variation of T/ET, as well as the factors influencing the variation in T/ET. The results showed that: (1) The PT-JPL model is suitable for the simulation of evapotranspiration and its components of forest ecosystems in Eastern China, and has relatively good stability and reliability. (2) Spatial distribution of T/ET in forest ecosystems along NSTEC was heterogeneous, i.e., T/ET was higher in the north and lower in the south, with an averaged value of 0.69; and the inter-annual variation of T/ET showed a significantly increasing trend, with an increment of 0.007/yr (p<0.01). (3) Seasonal and inter-annual variations of T/ET had different dominant factors. Temperature and EVI can explain around 90% (p<0.01) of the seasonal variation in T/ET, while the inter-annual variation in T/ET was mainly controlled by EVI (53%, p<0.05).

This article describes the lake basins of the Jom-Bolok volcanic region in the East Sayan (the largest manifestation of the Holocene eruptions in Central Asia). The geomorphological position, origins, aspects of the structure and development are reviewed considering its sedimentary filling. The limnic morphogenesis here develops under the conditions of contrasting relief, high energy of neotectonic and exogenous processes. We established that Lake Khara-Nur, formed as a result of lava-damming of the Jom-Bolok river valley, emerged in its present form approximately 6500 years ago. A complex record on the environment and climatic changes, acquired from its sediments, made it possible to determine for the first time in this region the long-term trends in the development of the Middle and Late Holocene mountain geosystems and also the distinction of several paleogeographic stages of the formation of the natural environment. An average geochemical record resolution for the bottom sediments of the lake was made uniquely for the East Siberian lake records and is equal to 35 years, while the palynological record approximates 110 years.

We analyzed the spatial local accuracy of land cover (LC) datasets for the Qiangtang Plateau, High Asia, incorporating 923 field sampling points and seven LC compilations including the International Geosphere Biosphere Programme Data and Information System (IGBPDIS), Global Land cover mapping at 30 m resolution (GlobeLand30), MODIS Land Cover Type product (MCD12Q1), Climate Change Initiative Land Cover (CCI-LC), Global Land Cover 2000 (GLC2000), University of Maryland (UMD), and GlobCover 2009 (GlobCover). We initially compared resultant similarities and differences in both area and spatial patterns and analyzed inherent relationships with data sources. We then applied a geographically weighted regression (GWR) approach to predict local accuracy variation. The results of this study reveal that distinct differences, even inverse time series trends, in LC data between CCI-LC and MCD12Q1 were present between 2001 and 2015, with the exception of category areal discordance between the seven datasets. We also show a series of evident discrepancies amongst the LC datasets sampled here in terms of spatial patterns, that is, high spatial congruence is mainly seen in the homogeneous southeastern region of the study area while a low degree of spatial congruence is widely distributed across heterogeneous northwestern and northeastern regions. The overall combined spatial accuracy of the seven LC datasets considered here is less than 70%, and the GlobeLand30 and CCI-LC datasets exhibit higher local accuracy than their counterparts, yielding maximum overall accuracy (OA) values of 77.39% and 61.43%, respectively. Finally, 5.63% of this area is characterized by both high assessment and accuracy (HH) values, mainly located in central and eastern regions of the Qiangtang Plateau, while most low accuracy regions are found in northern, northeastern, and western regions.

The risk posed by natural disasters can be largely reflected by hazard and vulnerability. The analysis of long-term hazard series can reveal the mechanisms by which risk changes. Drought disasters are one of the main types of disaster in the Tibet Region (TR) of China. In this study, using statistical drought disasters data in the TR from 1912 to 2012 and socio-economic statistics for five periods between 1965 and 2015, and adopting standard statistical analyses, a wavelet analysis, and a risk assessment model, we first construct the index system for drought disaster risk assessment, and then assess the risk of drought disasters and analyze the mechanisms of changes in risk. The results showed that the occurrence of drought in the TR had three distinct cycles during this study periods, with durations of 5, 15, and 27 years respectively. The frequency of drought in the TR showed increasing trends, and the cycle of drought had been prolonged. From 1965 to 2015, the risk of drought disaster in the TR is significantly increased with the growth rate of 6.8% in high-risk area. In addition, the severity of drought had enhanced, especially in Qamdo. The increased vulnerability locally and significantly enhanced hazard of drought disaster, with a shrinkage of 16.3% in the low-value area and an expansion of 7.4% in the high-value area, being the determinants of drought disaster risk. Therefore, agricultural areas of the TR are the focal locations where risk of drought disaster needs to be managed.

Central Asia features an arid and semi-arid climate, and the region is undergoing urbanization in the context of a fragile eco-environment. The influence of specific historical events in this region also persists on this ongoing urbanization. This study examines the mechanism of interaction between urbanization and the resource environment in Central Asia. The following results were obtained. (1) In different periods—Russian colonization, the era of the Soviet Union, and Central Asian countries as independent—the interactions between urbanization and the resource environment varied. (2) Variations in land use within 50 km of major cities of the region reflect both the trend of urbanization and that of variations in the eco-environment. In Kyrgyzstan and Tajikistan, where urbanization has been slow, the supportive effect of the eco-environment for urbanization was clear. In Uzbekistan and Turkmenistan, where freshwater resources are scarce, a close relationship was noted between urbanization and variations in the eco-environment. In Kazakhstan, fast urbanization has had a significant impact on the availability of water, grassland, and woodland in the relevant areas. (3) The efficiency of utilization of land and water resources is generally low. The compactness of the urban land of 47 major cities in Central Asia decreased from 0.44 in 1990 to 0.31 in 2015. Of them, 31 cities decreased in compactness, including all national capitals. Regardless of the level of urbanization, water consumption was high across the region. (4) The mechanisms of interaction between urbanization and the resource environment in Central Asia in the three stages were formulated to illustrate their specific temporal conductivity and spatial relevance.

In the context of accelerated development of the Silk Road Economic Belt, it is necessary to conduct in-depth research on urbanization of Central Asian countries. This paper analyzes the spatial and temporal patterns and evolution dynamics of urbanization during the period 1991-2017 from the perspective of internal-external forces. The results are as follows. (1) The urbanization process of the five Central Asian countries studied is significantly influenced by their political and economic situations and displays periodic characteristics. All five countries experienced a stagnation development stage at the beginning of independence, and then a rapid growth stage since the year 2000. The average annual growth rates of the two stages were 0.19% and 1.45%, respectively. (2) Differences in the urbanization of the studied countries are obvious, and the evolutionary characteristics of each subsystem of urbanization are different. It is therefore necessary to distinguish and clearly understand the urbanization process of each country. (3) Internal and external factors play a role in the urbanization processes of Central Asian countries. External railway transportation facilities are particularly important for the development of urbanization in these countries. The regression coefficients of railway construction length, total merchandise trade and actually utilized foreign capital are 0.5665, 0.0937 and 0.0806, respectively. (4) Countries with smaller populations and economic scales need to engage in international cooperation to promote healthy development of urbanization. The results of the study indicate that internal and external factors work together in the urbanization process of Central Asian countries, and external forces are particularly important for the development of such urbanization.

This study undertakes a systematic examination of characteristics of the spatio-temporal evolution of industrial economies in Central Asia from the perspectives of industrial scale, structural rationality, industrial competitiveness, and industrial isomorphism. The results show that industrial structures in Central Asian countries are becoming increasingly advanced, with certain differences among them in the characteristics of this evolution. Kazakhstan has long had a tertiary-secondary-primary industrial pattern, and productive services have played an increasingly prominent role in the development of its tertiary industry. The transformation of the industrial structure in Uzbekistan, from a secondary-tertiary- primary pattern at its independence from the Soviet Union to a tertiary-secondary-primary pattern, is apparent. Tajikistan’s industrial structure has also changed significantly in recent times. Its secondary industries shrunk while tertiary industries developed rapidly. In Kyrgyzstan, the ratios of secondary and tertiary industries to total industrial output have fluctuated significantly while considerable progress has been made in the service sector. The industrial structure of Turkmenistan is significantly lower than the other countries, and Turkmenistan is the only country in the Central Asian region which still shows a tertiary-secondary-primary industrial pattern. The feasibility and competitiveness of the industrial structures of these five Central Asian countries have different characteristics. Kazakhstan has structural advantages but lags in competitiveness, Uzbekistan is driven by both structural and competitive advantages, Tajikistan enjoys structural advantages while Kyrgyzstan lags behind in competitiveness, and Turkmenistan has a competitiveness-driven economy. Furthermore, values of the similar coefficient index of the three industrial structures in these countries were mostly above 0.95, the coefficients of the secondary industrial subdivisions in some countries were below 0.85, and those of tertiary industrial subdivisions among most countries were above 0.89, indicating considerable similarities in industrial structure among them. These findings are important in the context of establishing an effective industrial development strategy for the Silk Road Economic Belt, improving international cooperation, and upgrading industrial structures to achieve economic prosperity.

When viewed against the backdrop of globalization and the Belt and Road Initiative (BRI), Central Asia has ushered in new development opportunities. However, problems of ecological environment as a consequence of urbanization have begun to act as a constraint on the economic development of the region. the coupling coordination degree between the urbanization and ecological environment in Kazakhstan was analyzed by the coupling coordination degree model. The main controlling factors affecting its development were explored using a geographical detector. Several main conclusions can be drawn. (1) Kazakhstan's urbanization level, ecological environment level, and the coupling coordination degree between urbanization and ecological environment are all on the rise. (2) In terms of the comprehensive urbanization index, the western and eastern states have higher values than the southern and northern states. The spatial distribution pattern of the ecological environment index revealed high values in the eastern and western regions and low values in the central region. (3) The coupling coordination degree among the states of Kazakhstan is mostly at a low-moderate level. The spatial distribution shows that the coordination level of the east, middle, and west of the country is higher than that of south and north. (4) Indicators such as GDP per capita, social fixed asset investment per capita, employment in industry and services (% of total employment), and the number of college students per 10,000 people are important urbanization factors that affect the coupling coordination degree of urbanization and ecological environment. Indicators of farmland areas per capita, availability of water resources per capita, ecological land per capita and forest coverage in the ecological environment subsystem are important ecological environmental factors that affect the degree of coordination between urbanization and ecological environment in Kazakhstan. The interaction of the main elements in the two subsystems has a strong synergy.

Energy development has a significant impact on urbanization. This study employs the entropy method to evaluate the level of urbanization in Central Asia and further analyzes the possible dynamic transition mechanisms of the impact of energy development (characterized by energy development scale, energy trade, energy consumption, and energy endowment) on urbanization using the Panel Smooth Transition Regression model (PSTR). The results demonstrate that energy development in this region is characterized by “three highs and one low”, namely, high production volume, high export volume, high endowment, and low self-consumption, and plays a crucial role in the progress of urbanization. A nonlinear relationship is found to exist between energy development and comprehensive urbanization in the transition economies of Central Asia. Generally speaking, as energy development continues to expand, its impact on urbanization in this region has shifted from constraint to promotion, with the latter gradually tending to flatten out. Energy development characterized by energy development scale, energy consumption, and energy trade can prove the point, whose threshold is 1.47 million tons oil equivalent (Mtoe), 0.29 tons oil equivalent (toe) per capita, and 20.95 Mtoe, respectively. However, not all energy development models exhibit this behavior. Energy development characterized by energy endowment is such a case where the positive effect of it on comprehensive urbanization will be restrained when it exceeds 3.18. These findings can aid decision makers in seeking a better energy development model to promote the sustainable development of urbanization in Central Asia, avoiding energy resources waste and disorderly development.

Central Asia is emerging as an important pole of global economic and political power, thanks to its unique location at the heart of Eurasia and its abundance in energy reserves. This study explores the social power change in Central Asia from the perspective of cross-border mergers and acquisitions (M&A) by using the social network method. The main results are as follows: (1) The complexity of the energy M&A network has significantly decreased after the financial crisis in 2008. In the meantime, energy M&A became an important way to enhance energy power for buyer countries. Betweenness centrality is becoming the most significant factor affecting energy power, yet the effect of out-degree is weakening. (2) The community underwent multifaceted restructuring, which reflected the shift of energy power in Central Asia. Kazakhstan is the most powerful country in the energy sector in Central Asia. In addition, East Asian countries/regions, represented by China, are actively enhancing their energy power. (3) Different M&A modes reflect various M&A motivations of countries in the energy sector. In the future, more efforts should be made to promote the establishment of a pragmatic and efficient multilateral energy cooperation mechanism and strength the cooperation of the economy and energy finance when China participates in the energy market in Central Asia.

To ensure adequate oil supply and mitigate geopolitical uncertainties, China has diversified its sources of crude oil imports in recent years. Central Asia is a neighbor region of China, rich in oil and natural gas reserves, which can play an important role in China’s strategy to reduce its dependence on energy supplies from the Middle East. The geopolitical attributes of energy and the geopolitical situation in Central Asia determine that Central Asia’s energy development and cooperation are disturbed by domestic and foreign factors, and also face the risks of complex energy structural evolution and geopolitical games, which create a unique energy geopolitical pattern in Central Asia. This study proposes an analysis framework for energy geopolitics in Central Asia, arguing that the complexity of energy geopolitics in Central Asia can be demonstrated from the perspectives of both the main countries of energy development (game actors) and the whole-industry-chain of energy development (game themes). The most obvious feature of Central Asian energy geopolitics is the fierce game that is played between key countries and regions, Russia, the United States, China, the European Union (EU), Japan, India, Iran, and Turkey. Strategic geopolitical considerations and resource requirements necessitate the active participation of these players in Central Asian energy development and mean that the foreign policy agendas of states in this region are likely to become ever more crowded. Therefore, the energy cooperation between China and Central Asia faces the geopolitical risks of the great power games. It is necessary to develop reasonable and effective policies to establish guarantee mechanisms to minimize the risks of energy cooperation. This study characterizes the energy geopolitical strategies of Russia, the United States, China, and other related powers in Central Asia. It also assesses the country risks faced by energy cooperation between China and Central Asian countries. To withstand possible geopolitical and country risks, this study develops a series of policy frameworks which can be used to fortify the stability of the energy cooperation between China and Central Asian countries, and can also be effective in responding to the array of risks that might be encountered in the coming years.

Based on methods such as stochastic frontier production function, this paper analyses the changes of single factor productivity (SFP) and total factor productivity (TFP) of agriculture in the five Central Asian countries, during the period of 1992 to 2017. The research results show that the agricultural output in most of the five Central Asian countries has increased steadily, while agricultural labor productivity has shown a growth trend. With the exception of Kazakhstan, the land productivity of the other four countries shows a growth trend. In terms of factor input, the number of agricultural workers in the five Central Asian countries mainly shows a trend of decrease, with the input of chemical fertilizer increasing, and the amount of agricultural machinery increasing or decreasing within a small range. The total factor productivity in the five Central Asian countries has improved, but it is still at a low level. The policy suggestions contained in the research conclusions are as follows: (1) Promote the growth of agricultural TFP in the five Central Asian countries, and strengthen the emphasis on the input and allocation of agricultural factors; (2) be aware of the innovation of agricultural technology, as well as the promotion and diffusion of existing agricultural technologies, and improve the overall technical efficiency of agriculture; and (3) accelerate the effective flow of capital and other elements to the agricultural sector, improve infrastructure, better release the “dividend” of science and technology, and enhance the output efficiency.

In recent years, flows of many rivers and lakes have become reduced in arid and semi-arid regions around the world. The most typical examples of this phenomenon occur in Central Asia, and the reduction of the Aral Sea area is closely related to agricultural water use. However, due to a lack of continuous data in Central Asia spanning many years, “virtual water” is used to evaluate changes in agricultural water use. Based on virtual water theory, 325 kinds of agricultural products in eight categories are selected as the research object, and changes in virtual water are calculated for Central Asia from 1992 to 2016. Results indicate that: (1) The average annual net export of agricultural virtual water (TVWNE) in Central Asia is about 9 billion m3, concentrated in Kazakhstan, whose annual TVWNE reaches 8.1 billion m ³. (2) Since 2007, the TVWNE in Central Asia has dropped significantly, with a drop rate of 86%, while the total volume of agricultural virtual water has gradually increased since 1998. (3) The upstream and downstream countries in Central Asia have different characteristics in the change of virtual water quantity.

An exponential relationship between net primary productivity (NPP) and integrated NDVI has been found in this paper. Based on the relationship and using multi-temporal 8 km resolution NOAA AVHRR-NDVI data, the spatial distribution and dynamic change of NPP and fractional vegetation cover in the Yellow River Basin from 1982 to 1999 are analyzed. Finally, the effect of rainfall on NDVI is examined. Results show that mean NPP and fractional vegetation cover have an inclining trend for the whole basin, and rainfall in flood season influences vegetation cover most.

Based on the results of remote sensing investigations of the landscapes of 1995 and 2000, the national distribution of sandy desertified land and its interaction with other landscapes are classified, and five zonal types are distinguished. The data of nationally distributed 400 meteorological stations of 1999 are processed. With the GIS method, the data are spatially interpolated, and the national database of wind field concerned with wind erosion is established. In arid and semi-arid areas of China, the intensity of wind field is one of the key factors that controls the development of landscape especially in desert and its adjacent area. Different indexes are set up to describe the intensity of wind field, the method suggested by the wind erosion prediction models of RWEQ is also adopted to express the intensity of wind. The Weibull distribution is used to describe the wind field in China. Based on the analysis of the process of the wind erosion-driven landscape changes, this article proposes and discusses the control measures of wind erosion.

The impact of interbasin water transfer on environment is very significant. The affected area of the west route scheme of the South to North Water Transfer Project in China (SNWT) is located in the eastern Tibetan Plateau, where the altitude is high with frigid eco-environment. In this article, remote sensing and GIS are applied to analyze the natural environment and the natural environment index is established to express the natural conditions of the study area. After the natural environment index is divided into four grades and the features of each grade are analysed, some results are obtained for reference in environmental assessment of the west route of SNWT.

Asian monsoon have multiple forms of variations such as seasonal variation, intra-seasonal variation, interannual variation, etc. The interannual variations have not only yearly variations but also variations among several years. In general, the yearly variations are described with winter temperature and summer precipitation, and the variations among several years are reflected by circulation of ENSO events. In this study, at first, we analyze the relationship between land cover and interannual monsoon variations represented by precipitation changes using Singular Value Decomposition method based on the time series precipitation data and 8km NOAA AVHRR NDVI data covering 1982 to 1993 in east Asia. Furthermore, after confirmation and reclassification of ENSO events which are recognized as the strong signal of several year monsoon variation, using the same time series NDVI data during 1982 to 1993 in east Asia, we make a Principle Component Analysis and analyzed the correlation of the 7th component eigenvectors and Southern Oscillation Index (SOI) that indicates the characteristic of ENSO events, and summed up the temporal-spatial distribution features of east Asian land cover’s inter-annual variations that are being driven by changes of ENSO events.

Based on the continuous monitoring data of hydrology and water quality in the period from 1972 to 1997, the responses of hydro-environment system to melt water in the Second Songhua River basin were derived. Because of melt water, the water quality in the Second Songhua River is good and changes very except that the contents of Hg and Mn in the water are higher. The contribution of melt water to the water fluxes in the Second Songhua River basin is distinct: the water flow in April increases remarkably, reaches the peak in the upper reaches. The pollutant contributions and water pollution indices (WPIs) of the Second Songhua River in April are high in the upper reaches while that in the lower reaches are low. The responses of hydro-environment system to melt water of that basin are affected by content of packed snow and the underlining surface systems.

Remote-sensing and field data of Guizhou forest resources in 2000 are processed using ArcGIS, with the production of forest resource distribution map, forest age class structure map, and forest canopy distribution map. Analysis of these data shows that: (1) though there are multiple types of forest resources, forest coverage is low (only 25.27%, excluding sparse woodland, shrub and underage-forest); (2) the geographical distribution of forests is quite uneven, mainly in the southeast of the province and in Zunyi prefecture; (3) the zonal evergreen broad-leaved forests have been seriously destroyed, with striking secondary features, i.e., coniferous forest and shrubbery account for the greatest proportion of Guizhou forests; (4) the timber-forest is much larger in area than shelter-forest and economic forest; (5) young-and-middle aged forests are more widely distributed than near-and-over matured forest; and (6) the forest of Guizhou is not enough to effectively protect the environment of karst mountain areas of the province.

Poyang Lake is the largest freshwater lake in China. This paper conducted a digital and rapid investigation of the lake’s wetland vegetation biomass using Landsat ETM data acquired on April 16, 2000. First, utilizing the false color composite derived from the ETM data as one of the main references, the authors designed a reasonable sampling route for field measurement of the biomass, and carried it out on April 18-28, 2000. Then after both the sampling data and the ETM data were geometrically corrected to an equal-area projection of Albers, linear relationships among the sampling data and some transformed data derived from the ETM data and the ETM 4 were calculated. The results show that the sampling data is best relative to the band 4 data with a high correlation coefficient of 0.86, followed by the DVI and NDVI data with 0.83 and 0.80 respectively. Therefore, a linear regression model, which was based on the field data and band 4 data, was used to estimate the total biomass of entire Poyang Lake, and then the map of the biomass distribution was compiled.