The suitability evaluation of population and settlements spatial layout in the mountainous areas is an important basis on which the scale of population and settlement after Wenchuan Earthquake is determined. Based on the statistical data of field research, this paper chooses 1264 towns in 51 counties as the scope of evaluation, selects eight indices in the evaluation index system which includes post-disaster population scale, population density, urbanization rate, the percentage of migrant workers, death rate by earthquake, the percentage of minorities, elevation-slope integrated terrain and comprehensive geological condition. Besides, this paper uses AHP supported by entropy technique and fuzzy membership function model to calculate the suitability evaluation index and then divides the disaster areas into five types: highly suitable area (area accounted for 11.03%), relatively highly suitable area (15.29%), moderately suitable area (29%), less suitable area (30.08%) and unsuitable area (14.6%). According to the result of suitability evaluation, this paper puts forward several suggestions for the reconstruction as follows: the urban system and the building of new countryside should be guided by the suitability evaluation subareas; post-earthquake reconstruction avoids zones near Longmenshan fracture and high-mountain gorge areas as far as possible; the scale of population and settlement should not exceed the capacity of resources and environment; population should be resettled as close as possible by considering adequately the heterogenicity and homogeneity of regional nationality culture characteristics; densely resettle the people at plains and hilly areas; encourage the migrant workers settle in the working place with their families voluntarily; and urban system reconstruction such as industry layout and important projects of lifeline should be guided by the spatial layout suitability evaluation.

The dust source and transporting system are two indispensable aspects in the process of loess-palaeosol accumulation. It has been proved that the dust of the Loess Plateau mainly comes from the northwestern inland gobi and desert, transported by the East Asia monsoon systems and westerlies. However, there are little researches with respect to the dust source and deposition dynamics of the upper reaches of the Huaihe River. In the present study, we investigated and collected the YPC section with high resolution in the upper reaches of the Huaihe River. The chronological frame was reconstructed by optically stimulated luminescence (OSL) dating and correlated with the published loess time series. By comparison of the magnetic susceptibility (MS) and grain size (GS) of loess-soil profile among YPC profile, XJN profile (western Loess Plateau) and the JYC profile (southern Loess Plateau), we find similar climate change and pedogenic process between the upper reaches of the Huaihe River and the Loess Plateau, both experienced an extreme dry and the weakest pedogenesis during the last glacial, followed by a transitional episodes from the cold-dry last glacial to the warm-humid mid-Holocene and increased pedogenesis in the early Holocene, then a most humid-warm and strong pedogenesis in the mid-Holocene, and climate deterioration and decreased pedogenesis occurred during the late Holocene. But the MS of loess-soil profile sequences in the upper reaches of the Huaihe River was much lower than those in the Loess Plateau, and the GS was much coarser than those in the Loess Plateau. Comparison of GS for these three profiles revealed that there were different dust sources, which belonged to different aeolian transporting systems. The loess in the upper reaches of the Huaihe River was a wind blown deposition of near source, while the coarser dust mainly came from loose alluvial deposits of alluvial and proluvial fans of the Yellow River. The yielding and carrying dynamics of the dust in the Huaihe River is the northeast wind prevails in the winter half year.

From July 2008 to August 2008, 72 leaf samples from 22 species and 81 soil samples in the nine natural forest ecosystems were collected, from north to south along the North-South Transect of Eastern China (NSTEC). Based on these samples, we studied the geographical distribution patterns of vegetable water use efficiency (WUE) and nitrogen use efficiency (NUE), and analyzed their relationship with environmental factors. The vegetable WUE and NUE were calculated through the measurement of foliar δ¹³C and C/N of predominant species, respectively. The results showed: (1) vegetable WUE, ranging from 2.13 to 28.67 mg C g^-1 H₂O, increased linearly from south to north in the representative forest ecosystems along the NSTEC, while vegetable NUE showed an opposite trend, increasing from north to south, ranging from 12.92 to 29.60 g C g^-1 N. (2) Vegetable WUE and NUE were dominantly driven by climate and significantly affected by soil nutrient factors. Based on multiple stepwise regression analysis, mean annual temperature, soil phosphorus concentration, and soil nitrogen concentration were responding for 75.5% of the variations of WUE (p<0.001). While, mean annual precipitation and soil phosphorus concentration could explain 65.7% of the change in vegetable NUE (p<0.001). Moreover, vegetable WUE and NUE would also be seriously influenced by atmospheric nitrogen deposition in nitrogen saturated ecosystems. (3) There was a significant trade-off relationship between vegetable WUE and NUE in the typical forest ecosystems along the NSTEC (p<0.001), indicating a balanced strategy for vegetation in resource utilization in natural forest ecosystems along the NSTEC. This study suggests that global change would impact the resource use efficiency of forest ecosystems. However, vegetation could adapt to those changes by increasing the use efficiency of shortage resource while decreasing the relatively ample one. But extreme impacts, such as heavy nitrogen deposition, would break this trade-off mechanism and give a dramatic disturbance to the ecosystem biogeochemical cycle.

The study developed a feasible method for large-area land cover mapping with combination of geographical data and phenological characteristics, taking Northeast China (NEC) as the study area. First, with the monthly average of precipitation and temperature datasets, the spatial clustering method was used to divide the NEC into four ecoclimate regions. For each ecoclimate region, geographical variables (annual mean precipitation and temperature, elevation, slope and aspect) were combined with phenological variables derived from the moderate resolution imaging spectroradiometer (MODIS) data (enhanced vegetation index (EVI) and land surface water index (LSWI)), which were taken as input variables of land cover classification. Decision Tree (DT) classifiers were then performed to produce land cover maps for each region. Finally, four resultant land cover maps were mosaicked for the entire NEC (NEC_MODIS), and the land use and land cover data of NEC (NEC_LULC) interpreted from Landsat-TM images was used to evaluate the NEC_MODIS and MODIS land cover product (MODIS_IGBP) in terms of areal and spatial agreement. The results showed that the phenological information derived from EVI and LSWI time series well discriminated land cover classes in NEC, and the overall accuracy was significantly improved by 5.29% with addition of geographical variables. Compared with NEC_LULC for seven aggregation classes, the area errors of NEC_MODIS were much smaller and more stable than that of MODIS_IGBP for most of classes, and the wall-to-wall spatial comparisons at pixel level indicated that NEC_MODIS agreed with NEC_LULC for 71.26% of the NEC, whereas only 62.16% for MODIS_IGBP. The good performance of NEC_MODIS demonstrates that the methodology developed in the study has great potential for timely and detailed land cover mapping in temperate and boreal regions.

The metropolitan resources comprehensive efficiencies (also called comprehensive technical efficiency, short for CTE, thereafter), change trends and causes are investigated using DEA and Malmquist index models, respectively, in China during the period 1990-2006. Firstly, the DEA model results show that the metropolitan CTE was just fair to middling with the characteristics of almost declining from the Eastern Coastal to Western China, and only few metropolises were DEA efficient. Secondly, the results also show that the PTE was correlated with the urban population sizes of metropolises negatively, and the SE correlated positively with the urban population sizes of metropolises in 1990, 2000 and 2006, that is, with urban population sizes getting larger the corresponding PTE was decreasing accordingly, and the SE was increasing consequently and the increasing rate was smaller with the scale increase. Thirdly, the influencing factors of metropolitan efficiency were SE and PTE in 1990 and 2000, respectively. But the PTE became the predominant influencing factor with the rapid expansions of built-up areas and population scales of metropolises in 2006. Fourthly, the Malmquist index results show that the CTE change trends were increasing weakly, the technological change trends were declining, and the TFP change trends were declining obviously during 1990-2006, in which they were all increasing during the sub-period 1990-2000, and all decreasing during the sub-period 2000-2006. Fifthly, the Malmquist index results also demonstrate that the CTE change trend was increasing weakly in the Eastern Coastal China, declining in Central China, and declining evidently in Western China. And with the urban population size increasing the increasing trends of SE became weaker and weaker. And the main causes for the CTE being not too high and its change trends and TFP change trends being increasing weakly lie mainly in the technological degeneracy and PTE change trends declining significantly during 2000-2006. Finally, the analyses show that the China's metropolitan population boom and the rapid spread of built-up area had really caused their resources efficiency losses.

In the urbanizing world, the Yangtze Delta Region (YDR) as one of the most developed regions in China, has drawn a lot of the world’s attention for the remarkable economic development achieved in the past decades. Nevertheless, the rapid economic development was certain to be accompanied by unprecedented consumption and loss of natural resources. Therefore, the analysis of the ecological situation and driving factors of environmental impact was of great significance to serve the local sustainable development decision- making and build a harmonious society. In this paper, the ecological footprint (EF) was taken as the index of the ecological environmental impact. With the help of Geographic Information System (GIS), we studied the spatiotemporal change of ecological footprint at two scales (region and city) and assessed urban sustainable development ability in YDR. Then we discussed the driving factors that affected the change of ecological footprint by the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model. The results showed that increasing trends of regional ecological footprint during 1998-2008 (1.70-2.53 ha/cap) were accompanied by decreasing ecological capacity (0.31-0.25 ha/cap) but expanding ecological deficit (1.39-2.28 ha/cap). The distribution pattern of ecological footprint and the degree of sustainable development varied distinctly from city to city in YDR. In 2008, the highest values of ecological footprint (3.85 ha/cap) and the lowest one of sustainable development index (SDI=1) in YDR were both presented in Shanghai. GDP per capita (A) was the most dominant driving force of EF and the classical EKC hypothesis did not exist between A and EF in 1998-2008. Consequently, increasing in ecological supply and reducing in human demand due to technological advances or other factors were one of the most effective ways to promote sustainable development in YDR. Moreover, importance should be attached to change our definition and measurement of prosperity and success.

The landscape pattern of Beijing wetlands has undergone a significant change as a result of natural and artificial elements. Supported by remote sensing and GIS technology, using multi-temporal TM images from 1984 to 2008 in Beijing, this paper analyzed the dynamic characteristics of wetlands landscape pattern through selected typical indices including patch area, patch average area, fractal dimension index, diversity, dominance, contagion indices and the spatial centroids of each wetlands type were calculated. Finally, the paper explored the evolution mode and driving factors of wetland landscape pattern. The results were obtained as follows: the total wetland area increased during the period 1984-1996, then decline from 1996 to 2004. The wetland area in 1994 accounted for only 47.37% of that in 2004. The proportion of artificial wetland area was larger than that of natural wetland. The proportion of reservoir wetland was 33.50% to 53.73% and had the maximum average area. pond and paddy field wetland type with the least average area accounted for 16.46% to 45.09% of the total wetland area. The driving forces of the natural river wetland were mainly natural elements; its fractal dimension index was greater than the others. The Shannon diversity index of wetland landscape increased from 1.11 in 1992 to 1.34 in 2004, indicating that the difference between proportions of each wetland type decreased and areas of each wetland type were evenly distributed. The contagion index went down from 65.59 to 58.41, indicating that the connectivity degraded. Miyun Reservoir had the largest area and its area change had a great impact on the location of the centroid. Wetland resources degenerated gradually from the joint effects of natural and artificial factors. During the period 2006-2008, the precipitation increased and the drought condition was relieved. The government implemented series of positive policies to save water resources, and the wetland area increased.

To tackle the issues concerning agriculture, farmers, and rural areas, the central government of China initiated a new strategy called ‘new countryside construction’ in 2005. For better understanding its actual effect, this paper analyzes the regional diversity of peasant household response to this new countryside construction strategy based on Kruskal-Wallis H test and sampling survey data from 586 households in the Bohai Rim Region (BRR), Yangtze River Delta Region (YDR), and Pan Pearl River Delta Region (PPR). The result indicates that regional diversity in eastern coastal China (ECC) does exist in the form of recognized priority sequence, policy requirements, expected policy effects, and behavior response. As a result of the deviation between local policy practice and households’ inherent demand, peasants fulfill their de facto demand via individual effort instead of government aid, and therefore the new countryside construction fails to carry out the expected target. It thus needs to shift the current policy priority, ensure the peasants’ mainstay role, and formulate scientific ‘Rules for new countryside construction’.

The urban-rural transformation from dichotomy to integration is a gradual process. Like rural areas in many countries, Chinese rural society is experiencing a decline in all spheres due to depopulation, aging, lack of economic opportunity, and so on. Aiming at solving the serious rural issues, China proposed the implementation of a rural revitalization strategy and the promotion of an integrated urban-rural development for the first time in 2017. This proposal marks the transformation of the urban-rural relationship, and the integrated urban-rural development reflects a significant conceptual change. Researches on issues of rural decline are urgently needed to determine the most effective method for rural revitalization and development from the perspective of the urban-rural dynamics. In this context, this paper focuses on studying the theory, technology and management of rural revitalization and development. We construct a theoretical framework for urban-rural integration based on population-land-industry-right between the urban and rural systems, regarding land engineering for land capacity building as the technical support and the rural land system reform and reconstruction as the policy support for management. This research will provide theoretical support for the implementation of China’s rural revitalization strategy.

Investigating the spatio-temporal transmission features and process of novel coronavirus disease 2019 (COVID-19) mitigation strategies are of great practical significance to understand the development of COVID-19 and establish international cooperation for prevention and control. In this paper, the cumulative number of confirmed cases, number of confirmed cases per day and cumulative number of deaths, were used to compare transmission paths, outbreaks timelines, and coping strategies of COVID-19 in China and the US. The results revealed that: first, the COVID-19 outbreaks in both China and the US exhibited a 6-week initiation stage. In China, the COVID-19 erupted in late January. It lasted only a short period of time and was almost completely contained within 6-8 weeks. But the COVID-19 erupted in early March in the US and was still in the peak or post-peak stage. Second, in China, the COVID-19 emerged in Wuhan and spread to other regions of Hubei Province and then nationwide, exhibiting a cross(“+”)-shaped of spread with Wuhan city as the center. Importantly, the COVID-19 in China had a large concentration and there were no national outbreaks. In contrast, the COVID-19 in the US first spread through New York and the western and eastern coasts but has since emerged throughout the entire country. Third, the lack of emergency response planning in both countries in the early stage (about 6-week) hampered COVID-19 prevention. However, actively high-pressure prevention and control measures were used to basically control COVID-19 in early March in China. And then China has gradually resumed business and production activities. Unfortunately, the US government missed the best opportunity to contain the epidemic. Faced with the choice between economic recovery and coronavirus containment, the US removed the quarantine and restriction measures too early. The COVID-19 is continuing to spread in the country and blossom everywhere, still showing no signs of receding.

Population migration, especially population inflow from epidemic areas, is a key source of the risk related to the coronavirus disease 2019 (COVID-19) epidemic. This paper selects Guangdong Province, China, for a case study. It utilizes big data on population migration and the geospatial analysis technique to develop a model to achieve spatiotemporal analysis of COVID-19 risk. The model takes into consideration the risk differential between the source cities of population migration as well as the heterogeneity in the socioeconomic characteristics of the destination cities of population migration. It further incorporates a time-lag process based on the time distribution of the onset of the imported cases. In theory, the model will be able to predict the evolutional trend and spatial distribution of the COVID-19 risk for a certain time period in the future and provide support for advanced planning and targeted prevention measures. The research findings indicate the following: (1) The COVID-19 epidemic in Guangdong Province reached a turning point on January 29, 2020, after which it showed a gradual decreasing trend. (2) Based on the time-lag analysis of the onset of the imported cases, it is common for a time interval to exist between case importation and illness onset, and the proportion of the cases with an interval of 1-14 days is relatively high. (3) There is evident spatial heterogeneity in the epidemic risk; the risk varies significantly between different areas based on their imported risk, susceptibility risk, and ability to prevent the spread. (4) The degree of connectedness and the scale of population migration between Guangdong’s prefecture-level cities and their counterparts in the source regions of the epidemic, as well as the transportation and location factors of the cities in Guangdong, have a significant impact on the risk classification of the cities in Guangdong. The first-tier cities - Shenzhen and Guangzhou - are high-risk regions. The cities in the Pearl River Delta that are adjacent to Shenzhen and Guangzhou, including Dongguan, Foshan, Huizhou, Zhuhai, Zhongshan, are medium-risk cities. The eastern, northern, and western parts of Guangdong, which are outside of the metropolitan areas of the Pearl River Delta, are considered to have low risks. Therefore, the government should develop prevention and control measures that are specific to different regions based on their risk classification to enable targeted prevention and ensure the smooth operation of society.

Land use and land cover (LULC) alteration has changed original energy balance and heat fluxes between land and atmosphere, and thus affects the structure characteristics of temperature and humidity fields over urban heterogeneous surfaces in different spatio-temporal scales. Lanzhou is the most typical river valley city of China, it is chosen as the case study. Typical river valley terrain, rapid urbanization and severe air pollution have caused unique urban climate and urban heat island (UHI) effects in Lanzhou. Firstly, the spatial structure characteristics and dynamic evolution of temperature and humidity fields in autumn are simulated by mobile measurement experiment and GIS spatial analysis method. The results show that temperature and humidity fields have significant dynamic change within a day, and have multiple center and multiple intensity level characteristics. Then, LULC and normalized difference vegetation index (NDVI) are extracted from remote sensing images, the distribution patterns of temperature and humidity fields have close relationships with LULC and NDVI. Moreover, there is a significant positive correlation between impervious surface area and thermal field intensity. A positive correlation between NDVI value and humidity field intensity has been found as well as a negative correlation between NDVI value and thermal field intensity. Finally, heat fluxes and energy balance characteristics between ground and atmosphere are analyzed based on the Bowen-ratio System experiments. This study could provide theoretical support and practical guidance for urban planning, urban eco-environment construction and air pollution prevention of river valley city.

Flood is one of the severest natural disasters in the world and has caused enormous causalities and property losses. Previous studies usually focus on flood magnitude and occurrence time at event scale, which are insufficient to contain entire behavior characteristics of flood events. In our study, nine behavior metrics in five categories (e.g., magnitude, duration, timing, rates of changes and variability) are adopted to fully describe a flood event. Regional and interannual variations of representative flood classes are investigated based on behavior similarity classification of numerous events. Contributions of geography, land use, hydrometeorology and human regulation on these variations are explored by rank analysis method. Results show that: five representative classes are identified, namely, conventional events (Class 1, 61.7% of the total), low discharge events with multiple peaks (Class 2, 5.3%), low discharge events with low rates of changes (Class 3, 18.1%), low discharge events with high rates of changes (Class 4, 10.8%) and high discharge events with long durations (Class 5, 4.1%). Classes 1 and 3 are the major flood events and distributed across the whole region. Class 4 is mainly distributed in river sources, while Classes 2 and 5 are in the middle and down streams. Moreover, the flood class is most diverse in normal precipitation years (2006, 2008-2010 and 2015), followed by wet years (2007, 2013-2014), and dry years (2011 and 2012). All the impact factor categories explain 34.0%-84.1% of individual flood class variations. The hydrometeorological category (7.2%-56.9%) is the most important, followed by geographical (1.0%-6.3%), regulation (1.7%-5.1%) and land use (0.9%-2.2%) categories. This study could provide new insights into flood event variations in a comprehensive manner, and provide decision-making basis for flood control and resource utilization at basin scale.

Since 2007, the Chinese government has initiated the building of national eco-cultural protection areas (NECPAs), thereby embarking on a signi?cant transformation of the model of intangible cultural heritage (ICH) protection in China. To understand the origin and outputs of this policy, this paper demonstrates the context of China’s NECPAs. It proposes a conceptual NECPA framework that mainly features regional overall ICH protection. This is followed by an examination of the case of Xiangxi in Western Hunan as a pilot zone for China’s eco-cultural protection. Xiangxi has performed much related work to promote NECPAs and made great progress in regional overall ICH protection. This insight suggests that there are bene?ts and costs associated with promotion of China’s NECPAs and regional overall ICH protection. Despite the advantages of institutional innovation, the unexpected side effects actually undermine the success of plan implementation.

Arbuscular mycorrhizal fungi (AMF) are universally mutualistic symbionts that colonize the fine roots of most vascular plants. However, the biogeographical patterns and driving factors of AMF diversity of plant roots in grasslands are not well investigated. In this study, we used high-throughput sequencing techniques and bioinformatics to evaluate the AMF richness of 333 individual plant roots in 21 natural grassland ecosystems in northern China, including the Loess Plateau (LP), the Mongolian Plateau (MP), and the Tibetan Plateau (TP). The AMF richness showed a significant parabolic trend with increasing longitude. In regional situations, the AMF richness in the grasslands of the MP (60.4 ± 1.47) was significantly higher than those of the LP (46.4 ± 1.43) and TP (44.3 ± 1.64). Plant traits (including plant families, genera, and functional groups) explained the most variation in the AMF richness across China’s grasslands, followed by energy and water; soil properties had the least effects. The results showed the biogeographical patterns of the AMF richness and the underlying dominant factors, providing synthetic data compilation and analyses in the AMF diversity in China’s grasslands.

Land use/cover change (LUCC) is a major factor affecting net primary production (NPP). According to the LUCC of the Loess Plateau from 2005 to 2015, the LUCC patterns in 2025 in three scenarios were predicted by using the Future Land Use Simulation (FLUS) model. Furthermore, taking the average NPP of various land use/cover types in 16 years as the reference scale, the changes in NPP in multi-scenario simulations are predicted and analyzed, and the impact of different land use/cover transfers on NPP is quantified. The results are as follows: (1) The land use/cover changes greatly in the baseline and fast development scenarios, and changes relatively little in the ecological protection scenarios. (2) The changes in NPP in different scenarios reflected the significant difference in the ecological protection effect. All the three scenarios promote an NPP increase, but the ecological protection scenario can promote NPP increases the most. (3) The changes in NPP caused by LUCC in the three scenarios reflected the significant difference in the various land use/cover types protection effect. Analyzing and predicting NPP changes in multi-scenario LUCC simulations in the future can provide a theoretical basis for decision makers to judge the future changes in ecological environments and ecological protection effects against different policy backgrounds.

?ngstr?m-Prescott equation (AP) is the algorithm recommended by the Food and Agriculture Organization (FAO) of the United Nations for calculating the surface solar radiation (R_s) to support the estimation of crop evapotranspiration. Thus, the a_s and b_s coefficients in the AP are vital. This study aims to obtain coefficients a_s and b_s in the AP, which are optimized for China’s comprehensive agricultural divisions. The average monthly solar radiation and relative sunshine duration data at 121 stations from 1957-2016 were collected. Using data from 1957 to 2010, we calculated the monthly a_s and b_s coefficients for each subregion by least-squares regression. Then, taking the observation values of R_s from 2011 to 2016 as the true values, we estimated and compared the relative accuracy of R_s calculated using the regression values of coefficients a_s and b_s and that calculated with the FAO recommended coefficients. The monthly coefficients, a_s and b_s, of each subregion are significantly different, both temporally and spatially, from the FAO recommended coefficients. The relative error range (0-54%) of R_s calculated via the regression values of the a_s and b_s coefficients is better than the relative error range (0-77%) of R_s calculated using the FAO suggested coefficients. The station-mean relative error was reduced by 1% to 6%. However, the regression values of the a_s and b_s coefficients performed worse in certain months and agricultural subregions during verification. Therefore, we selected the a_s and b_s coefficients with the minimum R_s estimation error as the final coefficients and constructed a coefficient recommendation table for 36 agricultural production and management subregions in China. These coefficient recommendations enrich the case study of coefficient calibration for the AP in China and can improve the accuracy of calculating R_s and crop evapotranspiration based on existing data.

Based on long-term measurement data of weather/ecological stations over China, this paper calculated and produced annually- and seasonally-averaged Photosynthetically Active Radiation (PAR) spatial data from 1961 to 2007, using climatological calculations and spatialization techniques. The spatio-temporal variation characteristics of annually- and seasonally-averaged PAR spatial data over China in recent 50 years were analyzed with Mann-Kendall trend analysis method and GIS spatial analysis techniques. The results show that: (1) As a whole, the spatial distribution of PAR is complex and inhomogeneous across China, with lower PAR in the eastern and southern parts of China and higher PAR in the western part. Mean annual PAR over China ranges from 17.7 mol m^-2 d^-1 to 39.5 mol m^-2 d^-1. (2) Annually- and seasonally-averaged PAR of each pixel over China are averaged as a whole and the mean values decline visibly with fluctuant processes, and the changing rate of annually-averaged PAR is –0.138 mol m^-2 d^-1/10a. The changing amplitudes among four seasons are different, with maximum dropping in summer, and the descending speed of PAR is faster before the 1990s, after which the speed slows down. (3) The analysis by each pixel shows that PAR declines significantly (α=0.05) in most parts of China. Summer and winter play more important roles in the interannual variability of PAR. North China is always a decreasing zone in four seasons, while the northwest of Qinghai-Tibet Plateau turns to be an increasing zone in four seasons. (4) The spatial distributions of the interannual variability of PAR vary among different periods. The interannual variabilities of PAR in a certain region are different not only among four seasons, but also among different periods.

This paper presents a scenario-based assessment of global future food security. To do that, the socio-economic and climate change scenarios were defined for the future and were linked to an integrated modeling framework. The crop yields simulated by the GIS-based Environmental Policy Integrated Climate (EPIC) model and crop areas simulated by the crop choice decision model were combined to calculate the total food production and per capita food availability, which was used to represent the status of food availability and stability. The per capita Gross Domestic Product (GDP) simulated by IFPSIM model was used to reflect the situation of food accessibility and affordability. Based on these two indicators, the future food security status was assessed at a global scale over a period of approximately 20 years, starting from the year 2000. The results show that certain regions such as South Asia and most African countries will likely remain hotspots of food insecurity in the future as both the per capita food availability and the capacity of being able to import food will decrease between 2000 and 2020. Low food production associated with poverty is the determining factor to starvation in these regions, and more efforts are needed to combat hunger in terms of future actions. Other regions such as China, most Eastern European countries and most South American countries where there is an increase in per capita food availability or an increase in the capacity to import food between 2000 and 2020 might be able to improve their food security situation.

This paper calculated spatial accessibility of all counties (city, urban district) in China with cost weighted distance method. Region divisions of county accessibility were conducted, and relation of traffic accessibility and population aggregation was discussed in this paper. The results indicated that county accessibility in China had mainly low values and a distribution structure of circle layer and reverse-to-natural gradient. There was an obvious correlation between county accessibility and population density in China. With these analyses, inner mechanisms of population migration in different traffic conditions and region types were revealed, and can provide useful proposals to regional planning, traffic planning and smart distribution of people in China.

Geomorphologic maps are one of the most fundamental materials of the natural environment. They have been widely used in scientific research, resource exploration and extraction, education and military affairs etc. An editorial committee was established in 2001 to collect materials for researching and compiling a set of new 1:1,000,000 geomorphologic atlas of China. A digital geomorphologic database was created with visual interpretation from Landsat TM/ETM imageries and SRTM-DEM etc. The atlas compiled from the database was finished. The main characteristics of the atlas are as follows: Firstly, Landsat TM/ETM imageries, published geomorphologic maps or sketches, geographical base maps, digital geological maps, and other thematic maps were collected, which were uniformly geometrically rectified, clipped into uniform sheets, and stored in the foundation database. Secondly, based on the legends of 15 sheets 1:1,000,000 maps published in the 1980s, a geomorphologic classification system was built by combining morphology and genesis types. The system comprised seven hierarchical layers: basic morphology, genesis, sub-genesis, morphology, micro-morphology, slope and aspect, material composition and lithology. These layers were stored in the database during visual image interpretation. About 2000 kinds of morpho- genesis and 300 kinds of morpho-structure were interpreted. Thirdly, the legend system was built, which included color, symbol bases and note bases etc., compilation standards and procedures were developed, 74 sheets of 1:1,000,000 covering all land and sea territories of China were compiled, the 1:1,000,000 geomorphologic atlas of the People’s Republic of China was finished and published. The atlas will fill the blanks in national basic scale thematic maps, and the geomorphologic database could be applied widely in many fields in the future.

Spatial relations, reflecting the complex association between geographical phenomena and environments, are very important in the solution of geographical issues. Different spatial relations can be expressed by indicators which are useful for the analysis of geographical issues. Urbanization, an important geographical issue, is considered in this paper. The spatial relationship indicators concerning urbanization are expressed with a decision table. Thereafter, the spatial relationship indicator rules are extracted based on the application of rough set theory. The extraction process of spatial relationship indicator rules is illustrated with data from the urban and rural areas of Shenzhen and Hong Kong, located in the Pearl River Delta. Land use vector data of 1995 and 2000 are used. The extracted spatial relationship indicator rules of 1995 are used to identify the urban and rural areas in Zhongshan, Zhuhai and Macao. The identification accuracy is approximately 96.3%. Similar procedures are used to extract the spatial relationship indicator rules of 2000 for the urban and rural areas in Zhongshan, Zhuhai and Macao. An identification accuracy of about 83.6% is obtained.

Afforestation in China’s subtropics plays an important role in sequestering CO₂ from the atmosphere and in storage of soil carbon (C). Compared with natural forests, plantation forests have lower soil organic carbon (SOC) content and great potential to store more C. To better evaluate the effects of afforestation on soil C turnover, we investigated SOC and its stable C isotope (δ¹³C) composition in three planted forests at Qianyanzhou Ecological Experimental Station in southern China. Litter and soil samples were collected and analyzed for total organic C, δ¹³C and total nitrogen. Similarly to the vertical distribution of SOC in natural forests, SOC concentrations decrease exponentially with depth. The land cover type (grassland) before plantation had a significant influence on the vertical distribution of SOC. The SOC δ¹³C composition of the upper soil layer of two plantation forests has been mainly affected by the grass biomass ¹³C composition. Soil profiles with a change in photosynthetic pathway had a more complex ¹³C isotope composition distribution. During the 20 years after plantation establishment, the soil organic matter sources influenced both the δ¹³C distribution with depth, and C replacement. The upper soil layer SOC turnover in masson pine (a mean 34% of replacement in the 10 cm after 20 years) was more than twice as fast as that of slash pine (16% of replacement) under subtropical conditions. The results demonstrate that masson pine and slash pine plantations cannot rapidly sequester SOC into long-term storage pools in subtropical China.

We analyzed the Normalized Difference Vegetation Index (NDVI) from satellite images and precipitation data from meteorological stations from 1998 to 2007 in the Dongting Lake wetland watershed to better understand the eco-hydrological effect of atmospheric precipitation and its relationship with vegetation. First, we analyzed its general spatio-temporal distribution using its mean, standard deviation and linear trend. Then, we used the Empirical Orthogonal Functions (EOF) method to decompose the NDVI and precipitation data into spatial and temporal modes. We selected four leading modes based on North and Scree test rules and analyzed the synchronous seasonal and inter-annual variability between the vegetation index and precipitation, distinguishing time-lagged correlations between EOF modes with the correlative degree analysis method. According to our detailed analyses, the vegetation index and precipitation exhibit a prominent correlation in spatial distribution and seasonal variation. At the 90% confidence level, the time lag is around 110 to 140 days, which matches well with the seasonal variation.

Based on the static opaque chamber method, the respiration rates of soil microbial respiration, soil respiration, and ecosystem respiration were measured through continuous in-situ experiments during rapid growth season in semiarid Leymus chinensis steppe in the Xilin River Basin of Inner Mongolia, China. Soil temperature and moisture were the main factor affecting respiration rates. Soil temperature can explain most CO₂ efflux variations (R²=0.376–0.655) excluding data of low soil water conditions. Soil moisture can also effectively explain most of the variations of soil and ecosystem respiration (R²=0.314–0.583), but it can not explain much of the variation of microbial respiration (R²=0.063). Low soil water content (≤5%) inhibited CO₂ efflux though the soil temperature was high. Rewetting the soil after a long drought resulted in substantial increases in CO₂ flux at high temperature. Bivariable models based on soil temperature at 5 cm depth and soil moisture at 0–10 cm depth can explain about 70% of the variations of CO₂ effluxes. The contribution of soil respiration to ecosystem respiration averaged 59.4%, ranging from 47.3% to 72.4%; the contribution of root respiration to soil respiration averaged 20.5%, ranging from 11.7% to 51.7%. The contribution of soil to ecosystem respiration was a little overestimated and root to soil respiration little underestimated because of the increased soil water content that occurred as a result of plant removal.

The spatial distribution and seasonal variation of the tide-induced Lagrangian Residual Circulations (LRC hereafter), wind-driven LRC, and the coupling dynamic characteristics were simulated using ECOM, given the Hellerman and Rosenstein global monthly-mean wind stresses. The results showed that the tide-induced LRC of the harmonic constituent m² bears an identical pattern in four seasons in the Bohai Sea: the surface one is weak with random directions; however, there exist a southeast current from the Bohai Strait to the Laizhou bay, and a weakly anticlockwise gyre in the south of the Bohai Strait for the bottom layer LRC. The magnitude of bottom layer tide-induced LRC is larger than the surface one, and moreover, it contributes significantly to the whole LRC in the Bohai Sea. Unlike the identical structure of the tide-induced LRC, the wind driven LRC varies seasonally under the prevailing monsoon. It forms a distinct gyre under the summer and winter monsoons in July and January respectively, but it seems weak and non-directional in April and September.

Given the great number of studies focusing on the temporal interaction between economic and environmental subsystems, it is useful to perform a quantitative spatial assessment of these subsystems. In this paper, comprehensive assessment indicators for regional economic development and environmental pollution subsystems are constructed. Then, the degree of coupling and coordination of the regional economy-environment system is calculated for 350 prefectural units in China. It is found that the economic development and environmental pollution in most prefectural units is still at a low level of coupling and coordination. According to the coupling and coordination values, the Chinese territory can be divided into four types of area: economy-environment harmonious area, economy-environment gearing area, economy-environment rivaling area and low coupling degree of economy-environment area. Based on a structural analysis of the industrial sector in the four types of areas, there is a spatial relationship between the regional industrial sector structure and the coupling-coordination level. In the economy-environment harmonious area, the sectors of manufacturing of high-technology and high value-added products, such as communications, computer and electronic equipment, transport equipment and electrical machinery, account for a large proportion of the value of local industrial output. The industrial value of the economy-environment gearing area is concentrated on the manufacturing of machinery and equipment, and contains a few polluting sectors such as ferrous and non-ferrous metallurgy, chemical manufacturing and electricity generation. The economy-environment rivaling area is the type of area where polluting sectors concentrate, such as iron and steel, petrifaction, coal mining, building materials and electricity generation. In the low coupling degree of economy-environment area, its industry is concentrated on the production and processing of primary products.

Choosing site area, cultural layer thickness, significant relics and significant remains as the variables, we applied cluster analysis to the ancient settlements of four cultural periods, respectively, which were Peiligang, Yangshao, Longshan and Xiashang, in 9000-3000 a BP, around Songshan Mountain. Through application of the SOFM (self-organizing feature map) networks, every type of ancient settlements was classified into different size-grades. By this means, the Peiligang settlements were divided into two grades, Yangshao and Longshan settlements were divided into three grades, respectively, and Xiashang settlements were divided into four grades. The results suggested that the size-grade diversity of ancient settlements was not significant during the Peiligang period in this area. Around the middle-late Yangshao period (5000 a BP), the size-grade diversity of ancient settlements began to appear, a process that continued during the Longshan period and finally matured in the Xiashang period. Moreover, the results reflected the regional differences in cultural characteristics in a particular period, which were mainly represented in that there were three Peiligang cultural systems distributed in different areas. Such differences also existed in the spatial distributive characteristics between the Xia and Shang cultures. Based on the size-grade study of ancient settlements in the Circum-Songshan area, it was found that the SOFM networks method was very suitable for size-grade classification of ancient settlements, since, using this method, adjacent cells would compete and learn from each other, a benefit that reduced the effect on classification by the inaccuracy of site acreages.

Man-land relationship research, as the core of geographical research, runs through each development stage of Geography. Based on extensive literature review, this paper systematically generalizes the connotations, research development and contents of man-land relationship in China. (1) It explores the connotations and evolvement rules of man-land relationship in different social development stages in China, and finds that the core role of man-land relationship in geographical research has been strengthened continuously. Changing with times, its connotations have been considerably enriched by sustainable development and other notions, and so does its theoretical system. (2) It applies the bibliometric method to sketch out the basic research status of man-land relationship in China. Specifically, it quantitatively identifies the funding sources, major research teams and journals for publication. It finds that the funding sources show a diversification trend with national funding being the primary source of research grants. The most competitive research teams are mainly concentrated in the Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences (CAS) and normal universities. Journals sponsored by The Geographical Society of China are most influential in publishing man-land relationship research. (3) As resources and environment are the fundamental carriers of man-land relationship, this study focuses further on the research on resource-environmental base of man-land relationship, and finds that the resource-environmental base research in China has gone through an evolution process from single factor perspective research to comprehensive multiple perspective research gradually. Research themes have also experienced similar changes from land, water, energy minerals or other single factor research to comprehensive factor research of resources and environment. Empirical study on national and regional development strategies is the feature of man-land relationship in China. More emphasis should be put on considering and following the changes in features of “man” and “land” and research on the impacts of new factors on man-land relationship in a developing and dynamic manner in the future. Particularly, we should pay more attention to research on the impacts of spatio-temporal changes in resource-environment absolute location on modes of man-land interaction, and to strengthening interdisciplinary research and systematic research on comprehensive techniques so as to advance the development of application of man-land relationship theories and practices.

The karst critical zone is an essential component of the carbon (C) pool, constituting the global C cycle. It is referred to as one of the “residual land sink” that remains largely indeterminate. Karst area (2.2×10⁷ km²) comprises 15% of the world’s land area, and karst area comprises 3.44×10⁶ km² of area in China. Due to the complexity of karst structure and its considerable heterogeneity, C sequestration rate estimations contain large inaccuracies, especially in relation to the different methods used in calculations. Therefore, we reevaluated rock weathering-related C sink estimations in China (approximately 4.74 Tg C yr^-1), which we calibrated from previous studies. Additionally, we stipulated that more comprehensive research on rock-soil-biology-atmosphere continuum C migration is essential to better understand C conversion mechanisms based on uncertainty analyses of C sink estimations. Moreover, we stressed that a collective confirmation of chemical methods and simulated models through a combined research effort could at least partially eliminate such uncertainty. Furthermore, integrated C cycling research need a long-term observation of the carbon flux of multi-interfaces. The enhanced capacity of ecosystem C and soil C pools remains an effective way of increasing C sink. Karst ecosystem health and security is crucial to human social development, accordingly, it is critical that we understand thresholds or potential C sink capacities in karst critical zones now and in the future.