With the environmental deterioration caused by the advance of climate change, soil salinization is a serious and growing global problem. Currently about 7% of the world's land surface is threatened by salinization. China is a country whose soils are severely affected by this problem, which, due to its extensive area, and wide distribution poses a serious threat to regional agricultural development. In this review, we summarize the framework for soil salinization research in China over the past 70 years, assess the weaknesses of existing research in both a domestic and international context, highlight the trends and key findings of global research about saline soils over the past 30 years, and propose six major fields and directions for future research on saline soil.

To understand the variations in vegetation and their correlation with climate factors in the upper catchments of the Yellow River, China, Normalized Difference Vegetation Index (NDVI) time series data from 2000 to 2010 were collected based on the MOD13Q1 product. The coefficient of variation, Theil-Sen median trend analysis and the Mann-Kendall test were combined to investigate the volatility characteristic and trend characteristic of the vegetation. Climate data sets were then used to analyze the correlation between variations in vegetation and climate change. In terms of the temporal variations, the vegetation in this study area improved slightly from 2000 to 2010, although the volatility characteristic was larger in 2000-2005 than in 2006-2010. In terms of the spatial variation, vegetation which is relatively stable and has a significantly increasing trend accounts for the largest part of the study area. Its spatial distribution is highly correlated with altitude, which ranges from about 2000 to 3000 m in this area. Highly fluctuating vegetation and vegetation which showed a significantly decreasing trend were mostly distributed around the reservoirs and in the reaches of the river with hydropower developments. Vegetation with a relatively stable and significantly decreasing trend and vegetation with a highly fluctuating and significantly increasing trend are widely dispersed. With respect to the response of vegetation to climate change, about 20-30% of the vegetation has a significant correlation with climatic factors and the correlations in most areas are positive: regions with precipitation as the key influencing factor account for more than 10% of the area; regions with temperature as the key influencing factor account for less than 10% of the area; and regions with precipitation and temperature as the key influencing factors together account for about 5% of the total area. More than 70% of the vegetation has an insignificant correlation with climatic factors.

Global solar radiation (GSR) is the most direct source and form of global energy, and calculation of its quantity is highly complex due to influences of local topography and terrain inter-shielding. Digital elevation model (DEM) data as a representation of the complex terrain and multiplicity condition produces a series of topographic factors (e.g. slope, aspect, etc.). Based on 1 km resolution DEM data, meteorological observations and NOAA-AVHRR remote sensing data, a distributed model for the calculation of GSR over rugged terrain within the Yangtze River Basin has been developed. The overarching model permits calculation of astronomical solar radiation for rugged topography and comprises a distributed direct solar radiation model, a distributed diffuse radiation model and a distributed terrain reflectance radiation model. Using the developed model, a quantitative simulation of the GSR space distribution and visualization has been undertaken, with results subsequently analyzed with respect to locality and terrain. Analyses suggest that GSR magnitude is seasonally affected, while the degree of influence was found to increase in concurrence with increasing altitude. Moreover, GSR magnitude exhibited clear spatial variation with respect to the dominant local aspect; GSR values associated with the sunny southern slopes were significantly greater than those associated with shaded slopes. Error analysis indicates a mean absolute error of 12.983 MJm^-2 and a mean relative error of 3.608%, while the results based on a site authentication procedure display an absolute error of 22.621 MJm^-2 and a relative error of 4.626%.

The Heihe River Basin is the second largest inland river basin in Northwest China and it is also a hotspot in arid hydrology, water resources and other aspects of researches in cold regions. In addition, the Heihe River Basin has complete landscape, moderate watershed size, and typical social ecological environmental problems. So far, there has been no detailed assessment of glaciers change information of the whole river basin. 1:50,000 topographic map data, Landsat TM/ETM+ remote sensing images and digital elevation model data were used in this research. Through integrated computer automatic interpretation and visual interpretation methods, the object-oriented image feature extraction method was applied to extract glacier outline information. Glaciers change data were derived from analysis, and the glacier variation and its response to climate change in the period 1956/1963-2007/ 2011 were also analyzed. The results show that: (1) In the period 1956/1963-2007/2011, the Heihe River Basin’s glaciers had an evident retreat trend, the total area of glaciers decreased from 361.69 km² to 231.17 km²; shrinking at a rate of 36.08%, with average single glacier area decrease 0.14 km²; the total number of the glaciers decreased from 967 to 800. (2) Glaciers in this basin are mainly distributed at elevations of 4300-4400 m, 4400-4500 m and 4500-4600 m; and there are significant regional differences in glaciers distribution and glaciers change. (3) Compared with other western mountain glaciers, glaciers retreat in the Heihe River Basin has a higher rate. (4) Analysis of the six meteorological stations’ annual average temperature and precipitation data from 1960 to 2010 suggests that the mean annual temperature increased significantly and the annual precipitation also showed an increasing trend. It is concluded that glacier shrinkage is closely related with temperature rising, besides, glacier melting caused by rising temperatures greater than glacier mass supply by increased precipitation to some extent.

Global warming has led to significant vegetation changes in recent years. It is necessary to investigate the effects of climatic variations (temperature and precipitation) on vegetation changes for a better understanding of acclimation to climatic change. In this paper, we focused on the integration and application of multi-methods and spatial analysis techniques in GIS to study the spatio-temporal variation of vegetation dynamics and to explore the vegetation change mechanism. The correlations between EVI and climate factors at different time scales were calculated for each pixel including monthly, seasonal and annual scales respectively in Qinghai Lake Basin from the year of 2001 to 2012. The primary objectives of this study are to reveal when, where and why the vegetation change so as to support better understanding of terrestrial response to global change as well as the useful information and techniques for wise regional ecosystem management practices. The main conclusions are as follows: (1) Overall vegetation EVI in the region increased 6% during recent 12 years. The EVI value in growing seasons (i.e. spring and summer) exhibited very significant improving trend, accounted for 12.8% and 9.3% respectively. The spatial pattern of EVI showed obvious spatial heterogeneity which was consistent with hydrothermal condition. In general, the vegetation coverage improved in most parts of the area since nearly 78% pixel of the whole basin showed increasing trend, while degraded slightly in a small part of the area only. (2) The EVI change was positively correlated with average temperature and precipitation. Generally speaking, in Qinghai Lake Basin, precipitation was the dominant driving factor for vegetation growth; however, at different time scale its weight to vegetation has differences. (3) Based on geo-statistical analysis, the autumn precipitation has a strong correlation with the next spring EVI values in the whole region. This findings explore the autumn precipitation is an important indicator, and then, limits the plant growth of next spring.

The spatially explicit reconstruction of historical land-cover datasets plays an important role in studying the climatic and ecological effects of land-use and land-cover change (LUCC). Using potential natural vegetation (PNV) and satellite-based land use data, we determined the possible maximum distribution extent of forest cover in the absence of human disturbance. Subsequently, topography and climate factors were selected to assess the suitability of land for cultivation. Finally, a historical forest area allocation model was devised on the basis of the suitability of land for cultivation. As a case study, we used the historical forest area allocation model to reconstruct forest cover for 1780 and 1940 in Northeast China with a 10-km resolution. To validate the model, we compared satellite-based forest cover data with our reconstruction for 2000. A one-sample t-test of absolute bias showed that the two-tailed significance was 0.12, larger than the significant level 0.05, suggesting that the model has strong ability to capture the spatial distribution of forests. In addition, we calculated the relative difference of our reconstruction at the county scale for 1780 in Northeast China. The number of counties whose relative difference ranged from -30% to 30% is 99, accounting for 74.44% of all counties. These findings demonstrated that the provincial forest area could be transformed into forest cover maps well using the model.

Soil carbon sequestration and potential has been a focal issue in global carbon research. Under the background of global change, the estimation of the size as well as its change of soil organic carbon (SOC) storage is of great importance. Based on soil data from the second national soil survey and field survey during 2011-2012, by using the regression method between sampling soil data and remote sensing data, this paper aimed to investigate spatial distribution and changes of topsoil (0-20 cm) organic carbon storage in grasslands of Inner Mongolia between the 1980s and 2010s. The results showed that: (1) the SOC storage in grasslands of Inner Mongolia between the 1980s and 2010s was estimated to be 2.05 and 2.17 Pg C, with an average density of 3.48 and 3.69 kg C·m^-2, respectively. The SOC storage was mainly distributed in the typical steppe and meadow steppe, which accounted for over 98% of the total SOC storage. The spatial distribution showed a decreased trend from the meadow steppe, typical steppe to the desert steppe, corresponding to the temperature and precipitation gradient. (2) SOC changes during 1982-2012 were estimated to be 0.12 Pg C, at 7.00 g C·m^-2·yr^-1, which didn’t show a significant change, indicating that SOC storage in grasslands of Inner Mongolia remained relatively stable over this period. However, topsoil organic carbon showed different trends of carbon source/sink during the past three decades. Meadow steppe and typical steppe had sequestered 0.15 and 0.03 Pg C, respectively, served as a carbon sink; while desert steppe lost 0.06 Pg C, served as a carbon source. It appears that SOC storage in grassland ecosystem may respond differently to climate change, related to vegetation type, regional climate type and grazing intensity. These results might give advice to decision makers on adopting suitable countermeasures for sustainable grassland utilization and protection.

Using the dataset provided by the Smithsonian Institution’s Global Volcanism Program, we have extracted the large volcanic eruptions (volcanic explosivity index ≥ 4) from the period 1750-2010 and have then analyzed the main characteristics of large volcanic eruptions since 1750 according to their geographic latitudes, their elevations, and the years and months in which they occurred. The results show that most large volcanic eruptions were located around the margins of the Pacific Ocean and the islands of Sumatra and Java, especially in the equatorial regions (10°N-10°S). Large volcanic eruptions were concentrated at 1000-2000 m elevations and in the months of January and April. There were more eruptions in the summer half-year (from April to September) than in the winter half-year (from October to the next March). Large volcanic eruptions have interdecadal fluctuations, including cycles of 15-25 years and 35-50 years, which were detected by Morlet wavelet analysis, with the fluctuations being more frequent after 1870 than before. During the periods 1750-1760, 1776-1795, 1811-1830, 1871-1890, 1911-1920 and 1981-1995, there were relatively many large volcanic eruptions.

This study presented a quantitative comparison of cockpit and doline karst by examining the numbers and characteristics of typical types of landform entities that are developed in Guilin (Guangxi, China), La Alianza (PR, USA), Avalton (KY, USA), and Oolitic (IN, USA). Five types of landform entities were defined: isolated hill (IH), clustered hills (CHs), isolated sinkhole (IS), clustered sinkholes (CSs), and clustered hills with sinkholes (CHSs). An algorithm was developed to automatically identify these types of landform entities by examining the contour lines on topographic maps of two cockpit karst areas (Guilin and La Alianza) and two doline karst areas (Oolitic and Avalton). Within each specific study area, the CHSs is the least developed type yet with a larger size and higher relief. The IH and IS entities are smaller in size, lower in relief, and outnumber their clustered counterparts. The total numbers of these types of entities are quite different in cockpit and doline karst areas. Doline karst is characterized by more negative (IS and CSs) than positive (IH and IHs) landforms and vice versa for cockpit karst. For example, the Guilin study area has 1192 positive landform entities in total, which occupy 9.81% of the total study area. It has only 622 negative landform entities occupying only 3.91% of the total study area. By contrast, the doline karst in Oolitic has 130 negative while only 10 positive landform entities. The positive and negative landforms in Oolitic occupy 12.68% and 2.61% of the total study area, respectively. Furthermore, average relief and slope of the landform entities are much higher and steeper in the cockpit karst than the doline karst areas. For instance, the average slope of CHs in Alvaton is 3.90 degrees while it is 19.78 degrees in La Alianza. The average relief of CSs is 4.07 m and 34.29 m in Oolitic and Guilin respectively. Such a difference within a specific area or between the cockpit and doline karst may reveal different controls on the development of karst landscape.

This paper proposed a method to retrieve the land surface reflectance from the HJ-1A/B CCD data. The aerosol optical depth (AOD), the most important factor affecting the atmospheric correction of CCD images at all bands, is proposed to retrieve from the CCD imagery by the approach of dense dark vegetation (DDV) method. A look-up table in terms of the transmittances, the path radiances and the atmospheric spherical albedo as functions of the AOD was established for a variety of sun-sensor geometry and aerosol loadings. The atmospheric correction is then achieved with the look-up table and the MODIS surface reflectance output (MOD09) as the priori datasets. Based on the retrieved AOD and the look-up table of atmospheric correction coefficients, the land surface reflectance was retrieved for the HJ-1A/B data according to the atmospheric radiative transfer equation. Some in-situ measurement Data for Yanzhou of Shandong province in East China and MODIS land surface reflectance products MOD09 are used to preliminarily validate the proposed method. The results show that the proposed method can remove effectively the atmospheric contributions, and the overall accuracy of the retrieval land surface reflectance can be improved substantially.

Innovative cities not only constitute an important basis for innovation activities, but also play a strategically critical role in constructing an innovative country, producing new forms of urban development, and fostering urban sustainable development. Currently, China is marching toward the goal of establishing an innovative country by 2020, but in the start-up phase of this process of innovative city construction, the fundamental transition from factor-driven development to innovation-driven development is not being realized. As a result, a wide gap currently exists between China’s innovative cities and the advanced innovative cities in developed countries. This paper argues that this necessary transition is being constrained by a series of bottlenecks in investment, income, techniques, contributions, and talents. The article takes 287 prefecture-level cities as its object of comprehensive assessment, developing a comprehensive assessment system for innovative cities and devising innovative monitoring system software in order to evaluate the current situation in China’s innovative city construction. The analysis addresses four key aspects - namely, independent innovation, industrial innovation, living environmental innovation, and institutional innovation - as well as the spatial heterogeneity of the innovative city construction process. The results demonstrate that the level of innovation in Chinese cities is low, and the paper warns that building an innovation-oriented country will, as a consequence, be difficult. Some 87.8% of the cities studied maintained comprehensive levels of innovation that were lower than the national average. The level of comprehensive innovation in a city was found to have close and positive correlation with economic development. The level of the eastern region of China was, in particular, found to be significantly higher than that of the central and western regions. The levels of urban independent innovation, industrial innovation, environmental innovation, and institutional innovation showed consistent spatial heterogeneity, as did the comprehensive level of innovation in cities. In the future, the authors suggest, China should speed up the construction process in accordance with the basic principles of “independent innovation, breakthroughs in key fields, market-oriented, regional interaction, talent-supported,” with the purpose of building up Beijing, Shenzhen, Shanghai, and Guangzhou as global innovation centers; and Nanjing, Suzhou, Xiamen, Hangzhou, Wuxi, Xi’an, Wuhan, Shenyang, Dalian, Tianjin, Changsha, Qingdao, Chengdu, Changchun, Hefei, and Chongqing as national innovation centers, by 2020. Through this process, China will finally build a national urban innovation network that includes 4 global innovative cities, 16 national innovative cities, 30 regional innovative cities, 55 local innovative cities, and 182 innovation-driven development cities, thereby contributing to the establishment of an innovative country by 2020.

Identifying the problem regions and regional problems, and thus improving regional policies, are crucial for the sustainable development of various economic entities. The coordinated development of industrialization, informatization, urbanization and agricultural modernization (hereinafter referred to as “Sihua”) is not only a practical need but an important strategic direction of integrating urban-rural development and regional development in recent China, and it also provides a significant perspective for identifying problem regions and regional problems so as to improve the regional policies. This study mainly aims to: firstly, establish a comprehensive evaluation index system so as to explore the spatial pattern of coordinated development of Sihua in China at prefecture level; secondly, to develop an evaluation criteria system to identify the problem regions and regional problems from the perspective of coordinated development of Sihua. This paper comes first in the scientific community to evaluate the coordinated development state of Sihua in China at prefecture level and identify the problem regions and regional problems from the perspective of Sihua development by quantitative analysis. This study may benefit the improvement of regional policies and thus contribute to the sustainable socio-economic development of China.

City growth patterns are attracting more attention in urban geography studies. This paper examines how cities develop and grow in the upper tail of size distribution in a large-scale economy based on a theoretical model under new economic geography framework and the empirical evidence from the US. The results show that cities grow in a sequential pattern. Cities with the best economic conditions are the first to grow fastest until they reach a critical size, then their growth rates slow down and the smaller cities farther down in the urban hierarchy become the fastest-growing ones in sequence. This paper also reveals three related features of urban system. First, the city size distribution evolves from low-level balanced to primate and finally high-level balanced pattern in an inverted U-shaped path. Second, there exist persistent discontinuities, or gaps, between city size classes. Third, city size in the upper tail exhibits conditional convergence characteristics. This paper could not only contribute to enhancing the understanding of urbanization process and city size distribution dynamics, but also be widely used in making effective policies and scientific urban planning.

The traditional data envelopment analysis (DEA), bootstrap-DEA and Malmquist models are employed to measure different tourism efficiencies and their spatial characteristics of 61 cities in six coastal urban agglomerations in eastern China. The following conclusions are drawn. (1) The comprehensive efficiency (CE) of urban tourism using the bootstrap-DEA model is lower than the CE level using the DEA-CRS model, which confirms the significant tendency of the DEA-CRS model to overestimate results. (2) The geometric CE averages of urban tourism in the Yangtze River Delta (YRD) and the Pearl River Delta (PRD) have changed from ineffective to effective since 2000, the averages in the Beijing-Tianjin- Hebei (BTH) and the Shandong Peninsula (SDP) have changed from ineffective to moderately effective since 2000, and those in the Central and Southern Liaoning (CSL) and the West Bank of Taiwan Strait (WBTS) have been ineffective since 2000. (3) The CE values of urban tourism in the PRD, the YRD, the BTH and the SDP have been slightly affected by the pure technical efficiency (PTE), whereas the CE values in the CSL and the WBTS have been slightly affected by the scale efficiency (SE) since 2000. (4) Spatially, the range of geometric averages of the total factor productivity (TFP) for the PRD, the YRD, the BTH, the SDP, the WBTS and the CSL has decreased sequentially, while the one for most cities in six urban agglomerations has exhibited a downward trend since 2000. (5) Collectively, the natural conditions, the economic policies and the tourism capital drive the SE change of urban tourism of the CSL and the WBTS. The tourism enterprises for increasing returns to scale and imitating innovative technology have an effect on the CE change of urban tourism in the BTH and the SDP. The tourism market competition drives the PTE change of urban tourism in the PRD and the YRD. Although the PTE and the SE of urban tourism in six coastal urban agglomerations suffer from uncertain events, the CE maintained overall sound momentum since

Understanding the topographic context preceding the development of erosive landforms is of major relevance in geomorphic research, as topography is an important factor on both water and mass movement-related erosion, and knowledge of the original surface is a condition for quantifying the volume of eroded material. Although any reconstruction implies assuming that the resulting surface reflects the original topography, past works have been dominated by linear interpolation methods, incapable of generating curved surfaces in areas with no data or values outside the range of variation of inputs. In spite of these limitations, impossibility of validation has led to the assumption of surface representativity never being challenged. In this paper, a validation-based method is applied in order to define the optimal interpolation technique for reconstructing pre-erosion topography in a given study area. In spite of the absence of the original surface, different techniques can be nonetheless evaluated by quantifying their capacity to reproduce known topography in unincised locations within the same geomorphic contexts of existing erosive landforms. A linear method (Triangulated Irregular Network, TIN) and 23 parameterizations of three distinct Spline interpolation techniques were compared using 50 test areas in a context of research on large gully dynamics in the South of Portugal. Results show that almost all Spline methods produced smaller errors than the TIN, and that the latter produced a mean absolute error 61.4% higher than the best Spline method, clearly establishing both the better adjustment of Splines to the geomorphic context considered and the limitations of linear approaches. The proposed method can easily be applied to different interpolation techniques and topographic contexts, enabling better calculations of eroded volumes and denudation rates as well as the investigation of controls by antecedent topographic form over erosive processes.

Urban land cover has major impacts on a city’s ecosystem services and the inherent quality of its urban residential environment. The spatio-temporal distribution of impervious surface area and green areas in Chinese cities has exhibited a significantly marked difference in comparison with USA cities. This study focused on monitoring and comparing the spatio-temporal dynamics, land cover patterns and characteristics of functional regions in six Chinese (n=3) and USA (n=3) cities. The study data were collated from Landsat TM/MSS imagery during the period 1978-2010. Results indicate that Chinese cities have developed compactly over the past three decades, while development has been notably dispersed among USA cities. Mean vegetation coverage in USA cities is approximately 2.2 times that found amongst Chinese urban agglomerations. Land use types within Chinese cities are significantly more complex, with a higher density of impervious surface area. Conversely, the central business district (CBD) and residential areas within USA cities were comprised of a lower proportion of impervious surface area and a higher proportion of green land. Results may be used to contribute to future urban planning and administration efforts in both China and the USA.

The quantity and spatial pattern of farmland has changed in China, which has led to a major change in the production potential under the influence of the national project of ecological environmental protection and rapid economic growth during 1990-2010. In this study, the production potential in China was calculated based on meteorological, terrain elevation, soil and land-use data from 1990, 2000 and 2010 using the Global Agro-ecological Zones model. Then, changes in the production potential in response to farmland changes from 1990 to 2010 were subsequently analyzed. The main conclusions were the following. First, the total production potential was 1.055 billion tons in China in 2010. Moreover, the average production potential was 7614 kg/ha and showed tremendous heterogeneity in spatial pattern. Total production in eastern China was high, whereas that in northwestern China was low. The regions with high per unit production potential were mainly distributed over southern China and the middle and lower reaches of the Yangtze River. Second, the obvious spatiotemporal heterogeneity in farmland changes from 1990 to 2010 had a significant influence on the production potential in China. The total production potential decreased in southern China and increased in northern China. Furthermore, the center of growth of the production potential moved gradually from northeastern China to northwestern China. The net decrease in the production potential was 2.97 million tons, which occupied 0.29% of the national total actual production in 2010. Third, obvious differences in the production potential in response to farmland changes from 1990 to 2000 and from 2000 to 2010 were detected. The net increase in the production potential during the first decade was 10.11 million tons and mainly distributed in the Northeast China Plain and the arid and semi-arid regions of northern China. The net decrease in the production potential during the next decade was 13.08 million tons and primarily distributed in the middle and lower reaches of the Yangtze River region and the Huang-Huai-Hai Plain. In general, the reason for the increase in the production potential during the past two decades might be due to the reclamation of grasslands, woodlands and unused land, and the reason for the decrease in the production potential might be urbanization that occupied the farmland and Green for Grain Project, which returned farmland to forests and grasslands.

Surface albedo is a primary causative variable associated with the process of surface energy exchange. Numerous studies have examined diurnal variation of surface albedo at a regional scale; however, few studies have analyzed the intra-annual variations of surface albedo in concurrence with different land cover types. In this study, we amalgamated surface albedo product data (MCD43) from 2001 to 2008, land-use data (in 2000 and 2008) and land cover data (in 2000); quantitative analyses of surface albedo variation pertaining to diverse land cover types and the effect of the presence/absence of ground snow were undertaken. Results indicate that intra-annual surface albedo values exhibit flat Gaussian or triangular distributions depending upon land cover types. During snow-free periods, satellite observed surface albedo associated with the non-growing season was lower than that associated with the growing season. Satellite observed surface albedo during the presence of ground snow period was 2-4 times higher than that observed during snow-free periods. Surface albedo reference values in typical land cover types have been calculated; notably, grassland, cropland and built-up land were associated with higher surface albedo reference values than barren while ground snow was present. Irrespective of land cover types, the lowest surface albedo reference values were associated with forested areas. Proposed reference values may prove extremely useful in diverse research areas, including ecological modeling, land surface process modeling and radiation energy balance applications.

The aim of this study is to establish several important factors representing land use intensification in cultivated land (denoted by CII), using a multi-dimensional approach to achieve realistic and practical cultivated land use policies in China. For this reason, the theoretical framework was first built to explain the changes of land use intensification in the cultivated land, and then the variables and index were further developed for the purpose of characterizing the dynamic trends and driving forces of the land use intensification in the cultivated land at the provincial level. The study results indicate that the extent of CII significantly increased during the period of 1996 to 2008, due to the extensive use of fertilizers, machinery and pesticide, increased labor and capital input, and intensified land use. Moreover, the principal component regression results show that the productivity of cultivated land, economic benefits of cultivated land, labor productivity, and land use conversion are the main factors affecting the village development. The first three factors play a positive role, while the last one has a negative effect on the land use intensification in the cultivated land. According to these results, the main policies for sustainable intensification in cultivated land are proposed. First, the sustainable pathways for intensification should be adopted to reduce the unsustainable uses of chemical fertilizer, agricultural chemicals, etc. Second, the conditions for agricultural production should be further improved to increase the cultivated land productivity. Third, it is very necessary and helpful for improving labor productivity and land use efficiency from the viewpoint of accelerated the cultivated land circulation. The last step is to positively affect the production activities of peasants by means of reforming the subsidy standards.

The distribution of plant species and relationships between species and soil factors in the east central part of Gurbantunggut Desert was studied to provide more insight into the flora and determine differences in vegetation across various parts of the desert. Two-way Cluster Analysis showed that the vegetation in the area could be divided into three groups, the first group was dominated by the shrub species, Ephedra przewalskii and the grass species, Carex physodes mainly in areas of flat grounds and gentle slopes; the second group was dominated by C. physodes, Artemisia songorica and A. xerophytica mainly on the slope of sand dunes and the third group was dominated by the shrub species, Haloxylon persicum mainly on the top of sand dunes. There was no difference in plant density between Groups 1 and 2 but there was a significant decrease in Group 3. Soil water under vegetation Group 3 was much lower than that in the other two groups at all soil depths. The EC, organic matter, total P and soluble Na, Ca and Mg varied very similarly with soil water. Canonical correspondence analysis (CCA) satisfactorily assessed the species-soil relations in the area. The distribution of plant species was strongly correlated with the soil factors of water content, organic matter, EC and nutrients. The variations in species occurrence explained by the three CCA axes were about 70%, indicating that some explanatory site variables may exist outside our studied parameters. Soil texture is suggested to be included in future studies to improve the explanation of CCA.

The Forest Landscape Model (FLM) is an efficiency tool of quantified expression of forest ecosystem’s structure and function. This paper, on the basis of identifying FLM, according to the stage of development, summarizes the development characteristics of the model, which includes the theoretical foundation of mathematical model, FLM of stand-scale, primary development of spatial landscape model, rapid development of ecosystem process model as the priority, and developing period of structure and process driven by multi-factor. According to the characteristics of different FLMs, this paper classifies the existing FLM in terms of mechanism, property and application, and elaborates the identifications, advantages and disadvantages of different types of models. It summarizes and evaluates the main application fields of existing models from two aspects which are the changes of spatial pattern and ecological process. Eventually, this paper presents FLM’s challenges and directions of development in the future, including: (1) more prominent service on the practical strategy of forest management’s objectives; (2) construction of multi-modules and multi-plugin to satisfy landscape research demand in various conditions; (3) adoption of high resolution’s spatial-temporal data; (4) structural construction of multi-version module; (5) improving the spatial suitability of model application.

In this study, we have used four methods to investigate the start of the growing season (SGS) on the Tibetan Plateau (TP) from 1982 to 2012, using Normalized Difference Vegetation Index (NDVI) data obtained from Global Inventory Modeling and Mapping Studies (GIMSS, 1982-2006) and SPOT VEGETATION (SPOT-VGT, 1999-2012). SGS values estimated using the four methods show similar spatial patterns along latitudinal or altitudinal gradients, but with significant variations in the SGS dates. The largest discrepancies are mainly found in the regions with the highest or the lowest vegetation coverage. Between 1982 and 1998, the SGS values derived from the four methods all display an advancing trend, however, according to the more recent SPOT VGT data (1999-2012), there is no continuously advancing trend of SGS on the TP. Analysis of the correlation between the SGS values derived from GIMMS and SPOT between 1999 and 2006 demonstrates consistency in the tendency with regard both to the data sources and to the four analysis methods used. Compared with other methods, the greatest consistency between the in situ data and the SGS values retrieved is obtained with Method 3 (Threshold of NDVI ratio). To avoid error, in a vast region with diverse vegetation types and physical environments, it is critical to know the seasonal change characteristics of the different vegetation types, particularly in areas with sparse grassland or evergreen forest.

Hydrological processes were compared, with and without the influence of precipitation on discharge, to identify the differences between glacierized and non-glacierized catchments in the Urumqi River source region, on the northern slope of the eastern Tianshan Mountains, during the melting season (May-September) in 2011. The study was based on hydrological data observed at 10-min intervals, meteorological data observed at 15-min intervals, and glacier melting and snow observations from the Empty Cirque, Zongkong, and Urumqi Glacier No.1 gauging stations. The results indicated that the discharge differed markedly among the three gauging stations. The daily discharge was more than the nightly discharge at the Glacier No.1 gauging station, which contrasted with the patterns observed at the Zongkong and Empty Cirque gauging stations. There was a clear daily variation in the discharge at the three gauging stations, with differences in the magnitude and duration of the peak discharge. When precipitation was not considered, the time-lags between the maximum discharge and the highest temperature were 1-3 h, 10-16 h, and 5-11 h at the Glacier No.1, Empty Cirque, and Zongkong gauging stations, respectively. When precipitation was taken into consideration, the corresponding time-lags were 0-1 h, 13 h, and 6-7 h, respectively. Therefore, the duration from the generation of discharge to confluence was the shortest in the glacierized catchment and the longest in the catchment where was mainly covered by snow. It was also shown that the hydrological process from the generation of discharge to confluence shortened when precipitation was considered. The factors influencing changes in the discharge among the three gauging stations were different. For Glacier No.1 station, the discharge was mainly controlled by heat conditions in the glacierized region, and the discharge displayed an accelerated growth when the temperature exceeded 5°C in the melt season. It was found that the englacial and subglacial drainage channel of Glacier No.1 had become simpler during the past 20 years. Its weaker retardance and storage of glacier melting water resulted in rapid discharge confluence. It was also shown that the discharge curve and the time-lag between the maximum discharge and the highest temperature could be used to reveal the evolution of the drainage system and the process of glacier and snow melting at different levels of glacier coverage.

The net accumulation record of ice core is one of the most reliable indicators for reconstructing precipitation changes in high mountains. A 20.12 m ice core was drilled in 2006 from the accumulation zone of Laohugou Glacier No.12 in the northeastern Tibetan Plateau, China. We obtained the precipitation from the ice core net accumulation during 1960-2006, and found out the relationship between Laohugou ice core record and other data from surrounding sites of the northeastern Tibetan Plateau. Results showed that during 1960-2006, the precipitation in the high mountains showed firstly an increasing trend, while during 1980 to 2006 it showed an obvious decreasing trend. Reconstructed precipitation change in the Laohugou glacier basin was consistent with the measured data from the nearby weather stations in the lower mountain of Subei, and the correlation coefficient was 0.619 (P<0.001). However, the precipitation in the high mountain was about 3 times more than that of the lower mountain. The precipitation in Laohugou Glacier No.12 of the western Qilian Mountains corresponded well to the net accumulation of Dunde ice core during the same period, tree-ring reconstructed precipitation, the measured data of multiple meteorological stations in the northeastern Tibetan Plateau, and also the changes of adjacent PDSI drought index. Precipitation changes of the Laohugou glacier basin and other sites of the northeastern Tibetan Plateau had significantly positive correlation with ENSO, which implied that the regional alpine precipitation change was very likely to be influenced by ENSO.

Water diversion projects are an effective measure to mitigate water shortages in water-limited areas. Understanding the risk of such projects increasing concurrent drought between the water intake and receiving regions is essential for sustainable water management. This study calculates concurrent drought probability between the water intake and receiving regions of the Hanjiang to Weihe River Water Diversion Project using Standardized Precipitation Index and Copula functions. Results showed an increasing trend in drought probability across both the water intake and receiving regions from 2.67% and 8.38% to 12.47% and 14.18%, respectively, during 1969-2018. The return period of concurrent drought decreased from 111.11 to 13.05 years, indicating larger risk of simultaneous drought between the two regions. Projections from CMIP6 suggested that under the SSP 2-4.5 and 5-8.5 scenarios, concurrent drought probability would increase by 2.40% and 7.72% in 2019-2050 compared to that in 1969-1990, respectively. Although increases in precipitation during 2019-2050 could potentially alleviate drought conditions relative to those during 1991-2018, high precipitation variability adds to the uncertainty about future concurrent drought. These findings provide a basis for better understanding concurrent drought and its impact on water diversion projects in a changing climate, and facilitate the establishment of adaptation countermeasures to ensure sustainable water availability.

Global warming has caused the Arctic Ocean ice cover to shrink. This endangers the environment but has made traversing the Arctic channel possible. Therefore, the strategic position of the Arctic has been significantly improved. As a near-Arctic country, China has formulated relevant policies that will be directly impacted by changes in the international relations between the eight Arctic countries (regions). A comprehensive and real-time analysis of the various characteristics of the Arctic geographical relationship is required in China, which helps formulate political, economic, and diplomatic countermeasures. Massive global real-time open databases provide news data from major media in various countries. This makes it possible to monitor geographical relationships in real-time. This paper explores key elements of the social development of eight Arctic countries (regions) over 2013-2019 based on the GDELT database and the method of labeled latent Dirichlet allocation. This paper also constructs the national interaction network and identifies the evolution pattern for the relationships between Arctic countries (regions). The following conclusions are drawn. (1) Arctic news hotspot is now focusing on climate change/ice cap melting which is becoming the main driving factor for changes in geographical relationships in the Arctic. (2) There is a strong correlation between the number of news pieces about ice cap melting and the sea ice area. (3) With the melting of the ice caps, the social, economic, and military activities in the Arctic have been booming, and the competition for dominance is becoming increasingly fierce. In general, there is a pattern of domination by Russia and Canada.

Special attention needs to be paid to achieve the world’s poverty reduction goal by 2030 in less than ten-year time. The paper aims to investigate the multidimensional poverty in South Asia in the period 2003-2019. It constructs the Multidimensional Poverty Index (MPI) by selecting ten indicators in the fields of health, education and living standards. The research results show that the MPI of South Asia decreases in the research period. Poor people in South Asian countries are still facing several forms of deprivation while cooking fuel, sanitation, housing, nutrition and years of schooling are the main restrictive factors to poverty reduction in this region. Pakistan, India and Bangladesh face the worst poverty situation in terms of health, education and living standards. Targeted poverty alleviation and resilient poverty reduction are proposed in the paper to improve the poverty reduction efficiency and individual/regional capacity against risks to avoid returning to poverty.

Industrial agglomeration is a highly prominent geographical feature of economic activities, and it is an important research topic in economic geography. However, mechanism-based explanations of industrial agglomeration often differ due to a failure to distinguish properly between the spatial distribution of industries and the stages of industrial agglomeration. Based on micro data from three national economic censuses, this study uses the Duranton-Overman (DO) index method to calculate the spatial distribution of manufacturing industries (three-digit classifications) in the Beijing-Tianjin-Hebei region (BTH region hereafter) from 2004 to 2013 as well as the hurdle model to explain quantitatively the influencing factors and differences in the two stages of agglomeration formation and agglomeration development. The research results show the following: (1) In 2004, 2008, and 2013, there were 124, 127, and 129 agglomerations of three-digit industry types in the BTH region, respectively. Technology-intensive and labor-intensive manufacturing industries had high agglomeration intensity, but overall agglomeration intensity declined during the study period, from 0.332 to 0.261. (2) There are two stages of manufacturing agglomeration, with different dominant factors. During the agglomeration formation stage, the main locational considerations of enterprises are basic conditions. Agricultural resources and transportation have negative effects on agglomeration formation, while labor pool and foreign investment have positive effects. In the agglomeration development stage, enterprises focus more on factors such as agglomeration economies and policies. Internal and external industry linkages both have a positive effect, with the former having a stronger effect, while development zone policies and electricity, gas, and water resources have a negative effect. (3) Influencing factors on industrial agglomeration have a scale effect, and they all show a weakening trend as distance increases, but different factors respond differently to distance.

The coordinated development of urban and rural territorial systems has long been a scientific issue of concern in geography and socioeconomic development in China. Based on Territorial Function Theory, this paper establishes a theoretical framework to support the coordinated development of urban and rural territorial systems, analyzes the trend of functional evolution, discusses the impact of efficient allocation and orderly element flow on system equivalence development, and puts forward approaches and policy suggestions for equilibrium development in the future. The main conclusions are as follows: (1) The evolution of urban and rural territorial functions has experienced four stages: rural to rural, rural to urban transition, rural to urban, and urban to urban. In this process, territorial functions have been developed to be hierarchical and advanced. (2) Functional evolution enables urban and rural comparative advantages to be transformed from value difference to value equivalence. Increasing the flow intensity and reconstructing the flow space have become the necessary conditions for the coordination of development. (3) Land is the most important resource in China, and land system reform is the key to achieving equivalence development of urban and rural territorial systems, thereby determining the future equilibrium development of the two systems.