Water resources in the arid land of Northwest China mainly derive from snow and glacier melt water in mountainous areas. So the study on onset, cessation, length, temperature and precipitation of snowmelt period is of great significance for allocating limited water resources reasonably and taking scientific water resources management measures. Using daily mean temperature and precipitation from 8 mountainous weather stations over the period 1960?2010 in the arid land of Northwest China, this paper analyzes climate change of snowmelt period and its spatial variations and explores the sensitivity of runoff to length, temperature and precipitation of snowmelt period. The results show that mean onset of snowmelt period has shifted 15.33 days earlier while mean ending date has moved 9.19 days later. Onset of snowmelt period in southern Tianshan Mountains moved 20.01 days earlier while that in northern Qilian Mountains moved only 10.16 days earlier. Mean precipitation and air temperature increased by 47.3 mm and 0.857℃ in the mountainous areas of Northwest China, respectively. The precipitation of snowmelt period increased the fastest, which is observed in southern Tianshan Mountains, up to 65 mm, and the precipitation and temperature in northern Kunlun Mountains increased the slowest, an increase of 25 mm and 0.617℃, respectively, while the temperature in northern Qilian Mountains increased the fastest, increasing by 1.05℃. The annual runoff is also sensitive to the variations of precipitation and temperature of snowmelt period, because variation of precipitation induces annual runoff change by 7.69% while change of snowmelt period temperature results in annual runoff change by 14.15%.

This study is focused on indexes for the rice chilling injury in Heilongjiang Province during 1960-2009. Firstly, we compared a new derived climate data weighted by rice planting density with the traditional method, and found that the new one is more reasonable to assess the impact of climate change on crop yields. Considering the frequency and intensity of rice chilling in the province, secondly, chilling indexes defined by meteorological, national and international levels were assessed. The result showed that the meteorological standards were suitable for the delayed-type injury, while the international one, so-called sum of Growing Degree Day below threshold (GDD_n-), characterized best the sterile-type chilling injury for rice. The explanation ability of the rice yield time series model including both injury types as two independent variables reached approximately 92% (p < 0.05). Finally, we concluded that the contribution rates of human and weather factors to rice yields are about 87.2% and 12.8% respectively, and as light increasing trend for sterile-type chilling injury was found during heading to flowing period in recent years, indicating a high chilling risk for rice planting in Heilongjiang Province in the future global warming.

Recently,important land use changes have occurred in the Black Sea coastal regions of Ístanbul due to urban growth and population increases.The objective of this study was to determine changes in land use in the Black Sea coastal regions of?stanbul between 1987 and 2007.Landsat 30 m satellite images from 1987 and 2007 are used in the study.The study area is 1000 m in width from the coastline to the land and the study has been carried out using the controlled classification method to classify areas into residential,agricultural, forest,bare land,brush/grassland,and lake/pond land classes.Land use changes between 1987 and 2007 were analysed in detail.Residential areas of the Black Sea coastal regions of Ístanbul increased by 122%over the two decades.Also an increase of 55%in agriculture areas was observed,while there were decreases of 26%in forest areas and 15%in free land. A 21%increase in the area of brush and grassland took place.Furthermore 79%of the study area was covered by residential areas in 2007.It is probable that pressure on the Ístanbul coastal regions will continue due to migraton and rapid urbanization.Therefore,Istanbul's Black Sea coastal regions should be maintained using a sustainable coastal management plan.

Runoff at the three time scales (non-flooding season, flooding season and annual period) was simulated and tested from 1958 to 2005 at Tangnaihai (Yellow River Source Region: YeSR), Zhimenda (Yangtze River Source Region: YaSR) and Changdu (Lancang River Source Region: LcSR) by hydrological modeling, trend detection and comparative analysis. Also, future runoff variations from 2010 to 2039 at the three outlets were analyzed in A1B and B1 scenarios of CSIRO and NCAR climate model and the impact of climate change was tested. The results showed that the annual and non-flooding season runoff decreased significantly in YeSR, which decreased the water discharge to the midstream and downstream of the Yellow River, and intensified the water shortage in the Yellow River Basin, but the other two regions were not statistically significant in the last 48 years. Compared with the runoff in baseline (1990s), the runoff in YeSR would decrease in the following 30 years (2010-2039), especially in the non-flooding season. Thus the water shortage in the midstream and downstream of the Yellow River Basin would be serious continuously. The runoff in YaSR would increase, especially in the flooding season, thus the flood control situation would be severe. The runoff in LcSR would also be greater than the current runoff, and the annual and flooding season runoff would not change significantly, while the runoff variation in the non-flooding season is uncertain. It would increase significantly in the B1 scenario of CSIRO model but decrease significantly in B1 scenario of NCAR model. Furthermore, the most sensitive region to climate change is YaSR, followed by YeSR and LcSR.

The expansion of agriculture is posited as one of the main dynamics of forest landscape change globally, and the robust modeling of these processes is important for policy as well as academic concern. This paper concerns a relatively small area of Yiluo River catchment where considerable attention has been paid to slow down the process of the expansion of agriculture into the remaining natural forests. In the present study, we reconstructed the former forest landscape structure and elucidated the landscape change during a period of about 15 years. Three sets (1987, 1996 and 2002) of maps derived from Landsat-5 images were used for analyses. The result showed that there was a decrease in the area of the forest landscape from 995.60 km² in 1987 to 650.50 km² in 2002. Then we examined the degree to which forest landscape conversion could be attributed to a set of factors identified as significant at broader scales, namely topography, distribution of the village clusters (centroids), distance from villages (centroids), and distance from forest edge (1987). By using “spatial analysis” in Arc/gis 8.3, the correlation between forest landscape change and driving factors was constructed. This study found that forest landscape conversion in this region was largely explained by elevation, slope and proximity to village.

The mouth bar in the Yangtze estuarine waterways has a significant influence on navigational transport within the estuary,flood discharge and construction of the Shanghai Port.In this paper the morphological evolution and mechanisms of mouth bar formation of the Yangtze estuarine waterways are studied by analyzing hundreds of years of historical data and the latest profile maps of some or the main mouth bar channels in the Yangtze Estuary. The results are shown as follows:The mouth bars in the North Branch have moved gradually from outside the mouth to the inside and formed a huge sand bar.In the North Channel,the head of the mouth bar has migrated about 30 kilometers downstream,and a channel bar has been developing since 2001.Two mouth bar tops,which always existed in the North Passage, disappeared in 2010.The head of the mouth bar in the South Passage has migrated downstream about 14 km and the number of tops increased at first but is reduced to only one now. According to the results,we can conclude that the evolution of the mouth bars differs depending on their location.In the North Branch it is directly related to large-scale reclamation in Chongming Island,but in the North Passage it has a close relationship with regulation of the Yangtze Estuary Deepwater Channel.However,the evolution of mouth bars in the North Channel and South Passage is not only connected with the Yangtze Estuary Deepwater Channel Regulation Project,but also with the reclamation in the East Hengsha Shoal and the closure of the Qingcaosha Reservoir.

The vegetation coverage dynamics and its relationship with climate factors on different spatial and temporal scales in Inner Mongolia during 2001–2010 were analyzed based on MODIS-NDVI data and climate data.The results indicated that vegetation coverage in Inner Mongolia showed obvious longitudinal zonality,increasing from west to east across the region with a change rate of 0.2/10°N.During 2001–2010,the mean vegetation coverage was 0.57,0.4 and 0.16 in forest,grassland and desert biome,respectively,exhibiting evident spatial heterogeneities.Totally,vegetation coverage had a slight increasing trend during the study period.Across Inner Mongolia,the area of which the vegetation coverage showed extremely significant and significant increase accounted for 11.25%and 29.13%of the area of whole region,respectively,while the area of which the vegetation coverage showed extremely significant and significant decrease accounted for 7.65%and 26.61%,respectively. On inter-annual time scale,precipitation was the dominant driving force of vegetation coverage for the whole region.On inter-monthly scale,the change of vegetation coverage was consistent with both the change of temperature and precipitation,implying that the vegetation growth within a year is more sensitive to the combined effects of water and heat rather than either single climate factor.The vegetation coverage in forest biome was mainly driven by temperature on both inter-annual and inter-monthly scales,while that in desert biome was mainly influenced by precipitation on both the two temporal scales.In grassland biome,the yearly vegetation coverage had a better correlation with precipitation,while the monthly vegetation coverage was influenced by both temperature and precipitation.In grassland biome,the impacts of precipitation on monthly vegetation coverage showed time-delay effects.

As important mechanisms of regional strategy and policy,prefecture-level regions have played an increasingly significant role in the development of China's economy.However, little research has grasped the essence of the economic development stage and the spatio-temporal evolution process at the prefecture level;this may lead to biased policies and their ineffective implementations.Based on Chenery's economic development theory,this paper identifies China's economic development stages at both national and prefectural levels. Both the Global Moran I index and the Getis–Ord Gi*index are employed to investigate the spatio-temporal evolution of China's economic development from 1990 to 2010.Major conclusions can be drawn as follows.(1)China's economic development is generally in the state of agglomeration.It entered the Primary Production Stage in 1990,and the Middle Industrialized Stage in 2010,with a‘balanced–unbalanced–gradually rebalanced' pattern in the process.(2)China's rapid economic growth experienced a spatial shift from the coastal areas to the the inland areas.Most advanced cities in mid-western China can be roughly categorized into regional hub cities and resource-dependent cities.(3)Hot spots in China's economy moved northward and westward.The interactions between cities and prefectures became weaker in Eastern China,while cities and prefectures in Central and Western China were still at the stage of individual development,with limited effect on the surrounding cities.(4)While the overall growth rate of China's economy has gradually slowed down during the past two decades,the growth rate of cities and prefectures in Central and Western China was much faster than those in coastal areas.(5)Areas rich in resources,such as Xinjiang and Inner Mongolia,have become the new hot spots of economic growth in recent years.For these regions,however,more attention needs to be paid to their unbalanced industrial structures and the lagging social development against the backdrop of the rapid economic growth, driven predominantly by the exploitation of resources.

Actual evapotranspiration is a key process of hydrological cycle and a sole term that links land surface water balance and land surface energy balance.Evapotranspiration plays a key role in simulating hydrological effect of climate change,and a review of evapotranspiration estimation methods in hydrological models is of vital importance.This paper firstly summarizes the evapotranspiration estimation methods applied in hydrological models and then classifies them into the integrated converting methods and the classification gathering methods by their mechanism.Integrated converting methods are usually used in hydrological models and two differences exist among them:one is in the potential evaporation estimation methods,while the other in the function for defining relationship between potential evaporation and actual evapotranspiration.Due to the higher information requirements of the Penman-Monteith method and the existing data uncertainty,simplified empirical methods for calculating potential and actual evapotranspiration are widely used in hydrological models. Different evapotranspiration calculation methods are used depending on the complexity of the hydrological model,and importance and difficulty in the selection of the most suitable evapotranspiration methods is discussed.Finally,this paper points out the prospective development trends of the evapotranspiration estimating methods in hydrological modeling.

The 2012 Annual Meeting of the Geographical Society of China(GSC)was held on October 12-14 in Henan University,Kaifeng,Henan Province.The meeting was co-sponsored by the GSC and Henan Association of Science and Technology,and co-hosted by Henan University with a history of 100 years and Henan University of Economics and Law.A total of around 1300 geographers throughout China participated in this meeting and more than 800 papers including 560 oral presentations were submitted and discussed.During the meeting,20 young scholars were prized for their excellent papers presented to this annual meeting.

Qinghai Lake and Zhuye Lake, ~400 km apart, are located in the northwest margin of the Asian summer monsoon. Water of these two lakes mostly comes from the middle and eastern parts of the Qilian Mountains. Previous studies show that the Holocene climate changes of the two lakes implied from lake records are different. Whether lake evaporation plays a role in asynchronous Holocene climate changes is important to understand the lake records. In this paper, we used modern observations beside Qinghai Lake and Zhuye Lake to test the impact factors for lake evaporation. Pan evaporation near the two lakes is mainly related to relative humidity, temperature, vapor pressure and sunshine duration. But temperature has different impacts to lake evaporation of the two lakes, which can affect Holocene millennial-scale lake level changes. In addition, differences in relative humidity on the millennial-scale would be more significant, which also can contribute to asynchronous lake records.

The damage of dwelling houses constitutes the primary cause of casualties and asset loss in seismic disasters that occurred in Chinese rural areas. The structure of houses is crucial for assessing the vulnerability of rural houses. However, at present, available data on rural housing structure are incomplete and their spatial scales are inconsistent. This paper estimated the amount and ratio of rural houses in five structures, namely ‘wood’, ‘brick’, ‘mixed’, ‘reinforced concrete’, and ‘other’, for 2380 counties across China. With the percentage sampling census data in 2005, four accuracy levels were specified. Then, a set of down-scaling models were established, where the impact of climate, economic development level and ethnic minority cultural factors on rural housing structure, as well as the spatial autocorrelation of neighboring spatial units were considered. Based on the estimation results, a database of county-level rural housing structure was established, based on which the vulnerability of rural houses in different areas was clarified.

From 1981 to 2010,the effects of climate change on evapotranspiration of the alpine ecosystem and the regional difference of effects in the Tibetan Plateau(TP)were studied based on the Lund-Potsdam-Jena dynamic vegetation model and data from 80 meteorological stations.Changes in actual evapotranspiration(AET)and water balance in TP were analyzed.Over the last 30 years,climate change in TP was characterized by sig- nificantly increased temperature,slightly increased precipitation,and decreased potential evapotranspiration(PET),which was significant before 2000.AET exhibited increasing trends in most parts of TP.The difference between precipitation and AET decreased in the south- eastern plateau and increased in the northwestern plateau.A decrease in atmospheric water demand will lead to a decreased trend in AET.However,AET in most regions increased be- cause of increased precipitation.Increased precipitation was observed in 86%of the areas with increased AET,whereas decreased precipitation was observed in 73%of the areas with decreased AET.

Global closed basins, occupying almost one fifth of the world’s land area, spatially coincide with arid and semiarid areas. Paleoclimatic proxies can indicate basin-wide environmental change and human activity. However, previous studies have not approached the use of proxies in the same way to reconstruct natural and anthropogenic processes at regional and global scales. Here we present a regional study to investigate the basic processes of paleoclimatic proxies, from a typical closed-basin system in arid China. We use multiple paleoclimatic proxies of surface samples and sediments, as well as groundwater and sediment ages to study environmental change and human activity. We then establish a dataset for paleoclimatic proxies from global closed basins and do a numerical analysis on it. Regional studies verify that human activity greatly impacts paleoclimatic proxies, especially with regard to surface samples, as well as groundwater age, but Holocene sediments are less affected. Results from global studies indicate that the major changing trend of the wet/dry status of closed basins is associated with the movement of the westerly jet streams controlled by long-term changes in winter insolation. There is an abrupt change between 1800 AD and 1900 AD, according to a numerical synthesis of paleoclimatic proxies from global closed basins, which can be linked to human impact. We suggest this time period can be considered as a start point for the Anthropocene based on the sedimentary evidence of closed basins, globally.

The Qinling Mountains, located at the junction of warm temperate and subtropical zones, serve as the boundary between north and south China. Exploring the sensitivity of the response of vegetation there to hydrothermal dynamics elucidates the dynamics and mechanisms of the main vegetation types in the context of changes in temperature and moisture. Importance should be attached to changes in vegetation in different climate zones. To reveal the sensitivity and areal differentiation of vegetation responses to hydrothermal dynamics, the spatio-temporal variation characteristics of the normalized vegetation index (NDVI) and the standardized precipitation evapotranspiration index (SPEI) on the northern and southern slopes of the Qinling Mountains from 2000 to 2018 are explored using the meteorological data of 32 meteorological stations and the MODIS NDVI datasets. The results show that: 1) The overall vegetation coverage of the Qinling Mountains improved significantly from 2000 to 2018. The NDVI rise rate and area ratio on the southern slope were higher than those on the northern slope, and the vegetation on the southern slope improved more than that on the northern slope. The Qinling Mountains showed an insignificant humidification trend. The humidification rate and humidification area of the northern slope were greater than those on the southern slope. 2) Vegetation on the northern slope of the Qinling Mountains was more sensitive to hydrothermal dynamics than that on the southern slope. Vegetation was most sensitive to hydrothermal dynamics from March to June on the northern slope, and from March to May (spring) on the southern slope. The vegetation on the northern and southern slopes was mainly affected by hydrothermal dynamics on a scale of 3-7 months, responding weakly to hydrothermal dynamics on a scale of 11-12 months. 3) Some 90.34% of NDVI and SPEI was positively correlated in the Qinling Mountains. Spring humidification in most parts of the study area promoted the growth of vegetation all the year round. The sensitivity of vegetation responses to hydrothermal dynamics with increasing altitude increased first and then decreased. Elevations of 800 to 1200 m were the most sensitive range for vegetation response to hydrothermal dynamics. The sensitivity of the vegetation response at elevations of 1200-3000 m decreased with increasing altitude. As regards to vegetation type, grass was most sensitive to hydrothermal dynamics on both the northern and southern slopes of the Qinling Mountains; but most other vegetation types on the northern slope were more sensitive to hydrothermal dynamics than those on the southern slope.

The red beds in Zhejiang province of China host the highest concentration of Danxia arched rock shelters in the world, just as the Colorado Plateau in the western USA hosts the world’s largest concentration of natural arches and bridges. This study investigated the geological background of the arched rock shelters and compared them to the natural arches and bridges, based on field study and a literature review. It was found that Zhejiang arched rock shelters differ from Colorado Plateau natural arches and bridges in geometry and formation mechanism. Statistical geometric data on arch geometry shows that Danxia arched rock shelters in Zhejiang tend to be relatively flat. They are relatively low features with long spans, and great depth. The natural arches and bridges on the Colorado Plateau are similar to each other, but the bridges are larger than the arches. The geometric differences between the arched landforms could be attributed to their different geologic history and to their different formation mechanisms. The arched rock shelters in Zhejiang are formed by differential weathering between sandstone and conglomerate due to moisture-induced tensile stresses. In contrast, natural arches on the Colorado Plateau are closely related to the Salt Valley anticline, vertical tectonic fractures, and horizontal discontinuities in rock fins. The Colorado Plateau natural bridges were formed by river erosion.

Promoting regional coordinated development strategy is one of the important strategies in the new period of China. Faced with the reality of unbalanced and insufficient regional development in China, it is objectively necessary to construct one or more main axes supporting the coordinated and balanced development of regions to become the identification line representing the pattern of coordinated regional development. The results show that the Bo-Tai line, the northwest-southeast axis connecting Bole of Xinjiang and Taipei of Taiwan, can be built into national development backbone line and regional balanced development line, just perpendicular to Hu Line. In 2016, the area of southwest half and northeast half of Bo-Tai Line accounts for 60%: 40%, while the population accounts for 45%: 55%, the economic aggregate accounts for 40%: 60%, the per capita GDP ratio accounts for 44%: 56%, the population density ratio accounts for 38%: 62%, the economic density ratio accounts for 32%: 68%, and the urbanization level ratio accounts for 48%: 52%. The main average indicators are gradually tending to balanced development pattern. Further analysis shows that Bo-Tai Line is a strategic shoulder pole connecting two core zones of “the Belt and Road”, and is the peaceful reunification line of China’s national tranquility and Taiwan’s return. Bo-Tai Line is also a solid line supported and connected by comprehensive transportation channels and a Pipa type symmetrical line for the development of cities and urban agglomerations. It is the backbone of the two-way opening up and the linkage development line between land and sea. It is also an important dividing line that promotes the coordinated development of the eastern, central and western regions, and addresses the imbalance and inadequacy of regional development. Bo-Tai Line plays an irreplaceable strategic role in promoting the coordinated and balanced regional development. It is suggested that the construction of Bo-Tai Line should be included in the national development strategy, and the development strategic plan of Bo-Tai Line should be formulated to fully release the multiple potential functions. We should build three strategic support points: the northwest endpoint, the central strategic node and the southeast endpoint; carry out a comprehensive scientific investigation of the Bo-Tai Line, and strengthen the scientific cognition and publicity; promote China’s development in a higher- level, higher-quality, more coordinated, safer and more civilized direction. Let Chinese know about the Bo-Tai Line, let the world know about the Bo-Tai Line, and let the Bo-Tai Line truly become the backbone of the great rejuvenation of the Chinese nation.

As the main form of new urbanization in China, urban agglomerations are an important platform to support national economic growth, promote coordinated regional development, and participate in international competition and cooperation. However, they have become core areas for air pollution. This study used PM_2.5 data from NASA atmospheric remote sensing image inversion from 2000 to 2015 and spatial analysis including a spatial Durbin model to reveal the spatio-temporal evolution characteristics and main factors controlling PM_2.5 in China’s urban agglomerations. The main conclusions are as follows: (1) From 2000 to 2015, the PM_2.5 concentrations of China’s urban agglomerations showed a growing trend with some volatility. In 2007, there was an inflection point. The number of low-concentration cities decreased, while the number of high-concentration cities increased. (2) The concentrations of PM_2.5 in urban agglomerations were high in the west and low in the east, with the “Hu Line” as the boundary. The spatial differences were significant and increasing. The concentration of PM _2.5 grew faster in urban agglomerations in the eastern and northeastern regions. (3) The urban agglomeration of PM_2.5 had significant spatial concentrations. The hot spots were concentrated to the east of the Hu Line, and the number of hot-spot cities continued to rise. The cold spots were concentrated to the west of the Hu Line, and the number of cold-spot cities continued to decline. (4) There was a significant spatial spillover effect of PM_2.5 pollution among cities within urban agglomerations. The main factors controlling PM_2.5 pollution in different urban agglomerations had significant differences. Industrialization and energy consumption had a significant positive impact on PM_2.5 pollution. Foreign direct investment had a significant negative impact on PM_2.5 pollution in the southeast coastal and border urban agglomerations. Population density had a significant positive impact on PM_2.5 pollution in a particular region, but this had the opposite effect in neighboring areas. Urbanization rate had a negative impact on PM_2.5 pollution in national-level urban agglomerations, but this had the opposite effect in regional and local urban agglomerations. A high degree of industrial structure had a significant negative impact on PM_2.5 pollution in a region, but this had an opposite effect in neighboring regions. Technical support level had a significant impact on PM_2.5 pollution, but there were lag effects and rebound effects.

Payments for Ecosystem Services (PES) programs have been implemented in both developing and developed countries to conserve ecosystems and the vital services they provide. These programs also often seek to maintain or improve the economic wellbeing of the populations living in the corresponding (usually rural) areas. Previous studies suggest that PES policy design, presence or absence of concurrent PES programs, and a variety of socioeconomic and demographic factors can influence decisions of households to participate or not in the PES program. However, neighborhood impacts on household participation in PES have rarely been addressed. This study explores potential neighborhood effects on villagers’ enrollment in the Grain-to-Green Program (GTGP), one of the largest PES programs in the world, using data from China’s Fanjingshan National Nature Reserve. We utilize a fixed effects logistic regression model in combination with the eigenvector spatial filtering (ESF) method to explore whether neighborhood size affects household enrollment in GTGP. By comparing the results with and without ESF, we find that the ESF method can help account for spatial autocorrelation properly and reveal neighborhood impacts that are otherwise hidden, including the effects of area of forest enrolled in a concurrent PES program, gender and household size. The method can thus uncover mechanisms previously undetected due to not taking into account neighborhood impacts and thus provides an additional way to account for neighborhood impacts in PES programs and other studies.

The semiconductor industry typifies the international division of labor and exhibits significant structural differences in global trade in key product segments. The evolution of cross-border trade flows and dependency relationships, as well as trade organization patterns of manufactured products, equipment and materials for manufacturing, are investigated by constructing a global semiconductor trade relationship matrix and using the Gini coefficient and trade dependency index. It was found that: (1) the global semiconductor trade is highly spatially unbalanced, with materials and equipment trade in particular highly concentrated in a few countries on both the supply and demand sides; (2) China has replaced the US as the largest global semiconductor trade player and has shaped the regionalized system of manufactured goods and materials trade with East and Southeast Asian economies, but its equipment trade is highly dependent on Europe and the US; (3) the semiconductor production model has promoted the regionalization of the east and southeast Asia region in the trade of manufactured products and materials, and developed economies such as the US, the EU, Japan, and South Korea have maintained their monopolistic advantage in the trade of semiconductor equipment by building exclusive innovation networks and establishing trade barriers. The monopolistic nature of the semiconductor equipment trade and the regionalization of manufactured goods and materials have formed the characteristics of the global semiconductor trade and are likely to be further strengthened in future trade.

Knowledge innovation is a key component of urban innovation function and an important basis for modern urban development. Combining the multidisciplinary research of knowledge innovation, this paper constructs a measurement framework of urban knowledge innovation function from the perspective of urban geography and analyzes its spatial pattern and influencing factors. The conclusions are as follows: (1) The function of urban knowledge innovation refers to the tasks and roles it undertakes in the process of knowledge creation, knowledge dissemination and knowledge application, which is based on the internal knowledge stock and external practice conditions to meet the needs of human survival and development in the new era. The measurement dimensions include functional scale, functional intensity, functional scale, and functional vitality. (2) The development level of knowledge innovation functions in Chinese cities is uneven, and the cities with outstanding knowledge innovation functions are mainly concentrated in the eastern coastal areas and a few developed areas in the central and western regions, forming the diamond-shaped knowledge innovation structure with the Beijing-Tianjin, the Yangtze River Delta, the Pearl River Delta, Shaanxi-Chengdu-Chongqing as the four vertices and central Wuhan and Hefei as the center. According to the Jenks natural breakpoint method, it is divided into national-level, regional-level, local-level and knowledge-innovative development cities. (3) The spatial differentiation characteristics of urban knowledge innovation function are simultaneously affected by various natural and human factors. Among them, economic environment, opening environment, and cultural environment have the strongest interactive explanatory power with other factors, and are the dominant factors affecting the city’s knowledge innovation function. In the future, China should fully considers the status and characteristics of the city’s own knowledge economy development with corresponding policies and measures suitable for the development of the city’s knowledge economy, and strengthen the dominant position of human and social factors in the constructing the city’s knowledge innovation function.

The Regional Comprehensive Economic Partnership (RCEP) was formally signed by the Association of Southeast Asian Nations (ASEAN) countries, along with China, Japan, South Korea, Australia, and New Zealand. This was a significant step towards regional integration in the Asia-Pacific region. Analysing the trade structure among member states is crucial in understanding the path to regional integration and policy implications of regional cooperation within the RCEP framework. Based on subdivided commodity data, this study reviews the evolution of merchandise trade in the RCEP region in the past two decades. It investigates the current trade structure of the RCEP, emphasising the relative importance of intra-regional versus extra-regional interdependence and the trade asymmetry of the regional members. The results of the study are as follows: First, the overall extent of regional trade integration in the RCEP region increased modestly from 2001 to 2018, indicating that the RCEP region was export-oriented and there was significant room for further expansion of regional trade. Second, most of the commodities traded in the RCEP region demonstrated much higher extra-regional interdependence than intra-regional in 2018, particularly labor-, capital-, and technology-intensive products such as television and radio apparatus. Third, the trade networks of the top five traded commodities were distinguished by large economic asymmetries, with China, Japan, and South Korea being the dominant regional powers. These findings have significant implications for understanding how to promote regional integration and cooperation. Besides expanding intra-regional trade, outward-oriented factors influenced by the regional powers—including consolidating the global advantages of manufacturing, stabilizing supply chains by including large resource countries, and attracting extra-regional investments—were also the main rationales for the conclusion of the RCEP.

Ecosystem services are the media and channels through which ecological elements, structures, functions, and products benefit human society. Regulating the utilization intensity and protection methods of society on the ecosystem according to the ecosystem service value (ESV) and its influencing mechanism is of great significance for achieving the sustainable development goals. This paper takes the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as the research object and describes the spatiotemporal evolution characteristics of ESV in the GBA from 2000 to 2015. Panel quantile regression is also implemented to increase the understanding of the influencing mechanism of ESV. The main results are as follows: (1) From 2000 to 2015, the total ESV declined with a decreasing rate. The areas of decline were mainly distributed in the central part of the GBA and areas along the Pearl River Estuary. (2) Elasticity index, indicating response of ESV to land use change, reached its peak (1.08). The spatial distribution of elasticity index showed that land use changes brought about more intense ESV variations at the junction of cities. (3) In areas with different ESV levels, the influencing factors have different effects. Land use integrity can only promote ecosystem service capabilities in low-ESV areas. The positive effect of temperature on ecosystem service capacity increases with the increase of ESV, which reflects the self-reinforcement of the ecosystem. Moreover, the negative effect of economic density on ecosystem service capacity decreases with the increase of ESV, which reflects the self-protection of the ecosystem. The combination of such self-reinforcement and self-protection will lead to an ESV gap between the high- and low-ESV areas, and induce the “natural Matthew effect.”

In this paper, we firstly constructed a theoretical framework based on major function-oriented zones (MFOZs). Then taking the Loess Plateau (LP) as the study area, we revealed the spatio-temporal differences and influencing factors of carbon emission equity by using the carbon equity model, Theil index, and Geo-detector. The results showed that: (1) From 2000 to 2017, the carbon equity of the Loess Plateau showed a downward trend, but the ecological carbon equity remained above 2.3, which was significantly higher than the economic carbon equity. (2) The ecological carbon equity in the Loess Plateau increased from the core of urban agglomeration to the periphery. The spatial pattern of economic carbon equity changed from low in the northeast and high in the southwest to low in the north and high in the south. The ecological support coefficient and economic contribution coefficient of provincial capital cities and their surrounding districts remained low since 2000. (3) The equity of carbon emissions in each function-oriented zone in the Loess Plateau was compatible with its orientation. The ecological carbon equity of the key ecological functional zones (KEFZs) was significantly higher than that of the key development zones (KDZs) and the major agricultural production zones (MAPZs), while the economic carbon equity of the KDZs was significantly higher than that of the MAPZs and the KEFZs. (4) The formation and evolution of the spatial differentiation pattern of carbon equity in the Loess Plateau was the result of the long-term interaction effects of geographic location, social economy, science and technology level, and policy system. Among them, eco-environmental protection policy, government financial support, and geographical location are the key driving factors for the spatial pattern of ecological carbon equity. Geographical location, social economic level, and science and technology level are the key factors driving the spatial pattern of economic carbon equity. According to this study, to achieving carbon equity on the Loess Plateau region, what the key approaches are to fully implement the planning of MFOZs, design differentiated regional carbon compensation mechanisms, improve energy efficiency and ecological environment capacity, and build a collaborative regional carbon emission governance system. This research can not only provide an effective framework for analysing the carbon equity, but also offer policy implication for promoting carbon emission reduction and achieving high-quality development goals in the ecologically fragile areas.

Cropping systems worldwide have been affected by the current trend in global warming and the optimization of cropping systems is an important area of research in the transition of agricultural land. The Loess Plateau is a typical ecologically fragile region with the most serious soil erosion in China. We carried out a field experiment in Yan’an city on the Loess Plateau to explore the effect of sowing date on crop growth and yield. We then analyzed the feasibility of a double-cropping system by considering climatic adaptability, ecological suitability and economic viability. Our results showed that different sowing dates resulted in significant differences in crop growth and that appropriate early sowing can result in higher crop yields for early maturing varieties. We showed that double-cropping systems of sweet maize (Zea mays)-forage rape and feed maize-forage rape are feasible on the Loess Plateau. We discuss the implications for the efficient use of farmland, which is important in guiding agricultural supply-side reform and the development of modern agricultural management.

How the dynamics in soil loss (SL) and sedimentation are affected by land use/cover change (LULCC) has long been one of the most important issues in watershed management worldwide, especially in fragile mountainous river basins. This study aimed to investigate the impact of LULCC on SL and sediment export (SE) in eastern regions of the Koshi River basin (KRB), Nepal, from 1990 to 2021. The Random Forest classifier in the Google Earth Engine platform was employed for land use/land cover (LULC) classification, and the Integrated Valuation Ecosystem Services and Trade-offs (InVEST) Sediment Delivery Ratio model was used for SL and SE modeling. The results showed that there was a pronounced increase in forest land (4.12%), grassland (2.35%), and shrubland (3.68%) at the expense of agricultural land (10.32%) in KRB over the last three decades. Thus, the mean SL and SE rates decreased by 48% and 60%, respectively, from 1990 to 2021. The conversion of farmland to vegetated lands has greatly contributed to the decrease in SL and SE rates. Furthermore, the rates of SL and SE showed considerable spatiotemporal variations under different LULC types, topographic factors (slope aspect and gradient), and sub-watersheds. The higher rates of SL and SE in the study area were observed mostly in slope gradient classes between 8° and 35° (accounting for 83%-91%) and sunny and semi-sunny slope aspects (SE, S, E, and SW) (accounting for 57%-65%). Although the general mean rate of SL presented a decreasing trend in the study area, the current mean SL rate (23.33 t ha^-1 yr^-1) in 2021 is still far beyond the tolerable SL rate of both the global (10 Mg ha^-1 yr^-1) and the Himalayan region (15 t ha^-1 yr^-1). Therefore, landscape restoration measures should be integrated with other watershed management strategies and upscaled to hotspot areas to regulate basin sediment flux and secure ecosystem service sustainability.

Snowmelt runoff is a vital source of fresh water in cold regions. Accurate snowmelt runoff forecasting is crucial in supporting the integrated management of water resources in these regions. However, the performances of such forecasts are often very low as they involve many meteorological factors and complex physical processes. Aiming to improve the understanding of these influencing factors on snowmelt runoff forecast, this study investigated the time lag of various meteorological factors before identifying the key factor in snowmelt processes. The results show that solar radiation, followed by temperature, are the two critical influencing factors with time lags being 0 and 2 days, respectively. This study further quantifies the effect of the two factors in terms of their contribution rate using a set of empirical equations developed. Their contribution rates as to yearly snowmelt runoff are found to be 56% and 44%, respectively. A mid-long term snowmelt forecasting model is developed using machine learning techniques and the identified most critical influencing factor with the biggest contribution rate. It is shown that forecasting based on Supporting Vector Regression (SVR) method can meet the requirements of forecast standards.

The evolution of point bars in changing sections of a downstream tidal current limit is periodic. Accordingly, assessing the critical morphology and hydrodynamic characteristics of point bar scour and the sediment transport process of scour sediment bodies can support river regulation and waterway maintenance. The frequent scour of point bars in changing sections of tidal current limits within the Yangtze River directly restricts waterway stability. This study examined the Fujiangsha reach of the Yangtze River, hydrological data on sediment transport, and riverbed topography from 1950. The Jingjiang bank tail exhibited an evolutionary cycle (siltation>scour>siltation), with a primary period ranging from 3-6 years. Additionally, certain morphological and dynamic conditions were necessary for scour. The Datong station flow (Q) ranged from 20,000-40,000 m³·s^-1 for ≥180 days·yr^-1, enabling the bank silt layers to widen. Scour occurred during flooding and was concentrated in areas 5.0-7.5 km downstream from Ebizui. When Q≥40,000 m³·s^-1, scouring occurred in the bank middle and lower reaches, whereas Q≥50,000 m³·s^-1 for >50 consecutive days, scour occurred at the tail as well. Moreover, the volume of the scour shoals increased with the number of high-flow days (≥60,000 m³·s^-1). Bottom sand transport mainly occurred in the low-bank zone. Before the project’s second phase, the longitudinal transport of the scouring sand bodies occurred as follows: Jingjiang bank > low bank on the north side of Shuangjiansha > Fubei anabranch. During the second phase, the longitudinal transport route changed to Jingjiang bank > Fubei anabranch. The Jingjiang bank volume was also reduced; thus, its development was controlled. Owing to changes in the longitudinal transport routes, dredging should be conducted in areas where scouring sand bodies are separately transported from the tail, thereby reducing the load of dredging and maintenance for the Fubei anabranch during dry years.

We present the first quantitative estimation of monsoon precipitation during the late glacial-Holocene in the sandy land of northern China, based on organic carbon isotopic composition data from a loess-sand sequence at margin of the Mu Us sandy land. We use the relationship between monsoon precipitation and the carbon isotopic composition of modern soils as an analogue, with a minor modification, to reconstruct precipitation back to c. 47 ka ago. The preliminary results indicate that annual monsoon precipitation was high after 8 ka, with an average of 435 mm; and it decreased during 18 and 8 ka with a mean value of 194 mm. The precipitation value of 47-18 ka varied between the two. We compare the reconstructed precipitation with other records and paleoclimatic modeling results, showing that our record agrees with reconstructions of the monsoon precipitation from other sources, even capturing short climatic events such as the Younger Dryas. We suggest that solar irradiance, high-latitude temperature/ice volume and local evaporation have together modified moistures in the sandy land.