Coordinated development is a major concern in the national strategy of the Yangtze River Economic Belt (YREB). However, there are few studies which have quantitatively measured the level of coordinated development in the YREB. This paper aims to propose an comprehensive index of coordinated development based on the theories of growth pole and complex ecosystem and new guidelines of development from the central government. The index is composed by 18 indicators within 4 domains including economic development, technology & innovation, communication & transportation, and ecological protection. The scores of coordinated development capability of the 110 prefecture-level cities in the YREB are calculated and examined using natural break point analysis, spatial autocorrelation analysis and rank-size analysis. It is shown that Shanghai, Nanjing and Wuhan are leading the coordinated development in the YREB. Generally, the scores of coordinated development capability are higher in the eastern region of the YREB, in which the cities perform well in the domains of economic development, technology & innovation and communication & transportation yet show poor performance in ecological protection. Most cities in the middle reach of Yangtze river rank in the middle in the YREB in all the domains, except the provincial capitals. The western region of the YREB gets the lowest score in the coordinated development capability besides the largest cities such as Chongqing, Chengdu, Kunming and Guiyang. The correlation coefficients between ecological protection and other domains are〖JP〗 very low, suggesting that few cities have achieved a win-win situation between environment protection and socio-economic development. We suggest three ways to promote coordinated development in the YREB: establishing multi-level institutional designs; enhancing the innovation in green industries; and strengthening the joint prevention and control of ecological risks.

It is essential to reveal the spatial-temporal coupling relationship between the change of regional transportation location and the expansion of construction land for exploring the driving force for the expansion of construction land, enhancing the effectiveness of regional construction land management and promoting the sustainable development of the region. Here, this paper reveals the spatial-temporal differentiation characteristics of regional traffic location and construction land expansion with spatial econometrics methods and explores the correlation between the two from the time series and space based on the remote sensing and traffic data from 1990 to 2015 in the middle reaches of the Yangtze River. We found that traffic accessibility in study area increased rapidly from 1990 to 2015. The average traffic accessibility of the county increased from 0.76 in 1990 to 1.14 in 2015, with an average annual growth rate of 1.52%. The average annual growth rate was 1.52%, of which the growth rate was the fastest in 1990-1995 years, and the growth of 2005-2010 years was slower. And the spatial distribution of high level accessibility area is distributed from sporadic point to linear distribution along the Yangtze River and its tributaries. The total increase of construction land area in the study area was 7 851.24 km² from 1990 to 2015, and the trend in expansion intensity decreased first and then increased. The high value area also showed a similar change from sporadic point to space along the Yangtze River and its tributaries. The expansion of regional construction land is not only related to its own traffic location, but also affected by its neighboring traffic location. The Pearson correlation coefficients of traffic accessibility and the logarithm of the expansion intensity are 0.577, 0.567, 0.470, 0.591 and 0.501 respectively, and the Moran’s I index is 0.235, 0.278, 0.251, 0.298, 0.278, respectively. There are similarities in the spatial aggregation characteristics of traffic accessibility and construction land expansion intensity in different periods: the provincial capital and its neighboring areas have a high-high aggregation state due to their location advantages, while hilly area shows low-oligomeric state due to its low economic activity and limited terrain conditions. It is vital for strategic planning of regional integration development in the new era to clarify the spatial-temporal coupling relationship between regional transportation location and construction land expansion.

Road network is the basis of social and economic development in rural areas. Based on the methods of road network and accessibility analysis, this paper build road network density, highway accessibility, closeness centrality, and straightness and other indicators to study the spatial pattern of road network accessibility in villages and towns, and correlated it with villagers’ spatial travel based on the survey of villagers. The results show that: (1) The density of roads is low and there are many broken roads in some villages, which cause poor accessibility in local areas; (2) The closeness centrality of each village shows a clear core-edge distribution pattern, affected by geographical location factors and highway coverage factors; (3) The shortage of high-grade road and it’s incompleteness greatly limit villagers’ travel efficiency and travel range, causing low satisfaction, and it holds back the progress of agricultural mechanization and the large-scale development of agricultural industry. Based on the characteristics of road network accessibility and villagers’ spatial travel demand, this paper gave advice on the road network remediation, the results might contribute to the study on road system in rural areas and the construction of new countryside. 

The concept of eco-efficiency integrates environmental performance with economic performance, which is in accord with ecological civilization construction and sustainable development strategy. Based on the panel data of 30 provincial economic units in China from 2004 to 2014,this article focused on the empirical estimation and the analysis of spatio-temporal correlation and spatial agglomeration of eco-efficiency through constructing a regional eco-efficiency evaluation model and exploratory spatial statistical analysis method. The driving factors in eco-efficiency evolution were also analyzed. The results show that, (1) Regional differentials of eco-efficiency are significant in China and shows a gradient descending pattern of "East, Middle, West and Northeast"; (2) Regional eco-efficiency shows the characteristics of significant positive spatial correlation and spatial agglomeration. The eco-efficiency of adjacent provinces affects each other, which implies that the spatial diffusion effects are remarkable. Hence, regional differentials and spatial factors cannot be ignored both in theory and in reality. (3) Factors, such as economic development level, environmental regulation, structural changes, open door policies and urbanization level, all significantly affect eco-efficiency. In order to improve the regional eco-efficiency in China, we should focus on the backward areas in the central and western regions.

In order to determining whether the population carrying capacity of land in Western China can meet the needs of population growth, economic development and the improvement of the life quality, and also to providing the basis for land use planning and population development strategy, this paper calculates the population carrying capacity in 2020, 2025 and 2030 in Western China based on the natural and economic attributes of the land.It uses the statistical model and grey prediction method to calculate the population carrying capacity based on the natural property of land. On the other hand, it uses the industrial activity correlation method of land function to calculate the population carrying capacity from the angle of land economic attribute. Finally, it uses the short board method to weigh the two calculation results and determines the actual land population carrying capacity of the western region, and compares it with the number of future population. The results show that the population carrying capacity of western region in 2020, 2025 and 2030 are 650 million, 673 million and 694 million people, while the number of population in the future are 381 million, 387 million and 392 million. The population carrying capacity of the western region should support the future population. From the point of regional distribution, 11 provinces can meet the need of future population growth such as Neimenggu, Guangxi, Chongqing, Sichuan, Ningxia, Xinjiang, etc. Only the population carrying capacity in Qinghai province is lower than the future population. It shows that the overall land carrying capacity of the western region can meet the needs of the population development.But there is regional incoordination.Land carrying capacity of Qinghai province will not match its population development needs.

Based on the land use data of the 6th period of Zhejiang Province from 1990 to 2015, the temporal and spatial changes of land use are analyzed, and the ecological risk index is constructed to evaluate the ecological risk of land use in Zhejiang Province in different periods. The results show that: (1) The land use change in Zhejiang Province is characterized by a large reduction in arable land and a sharp increase in construction land; the direction of land use transfer is mainly the transfer of cultivated land, forest land, and water areas to construction land; of which, the land use dynamic degree is the highest from 2000 to 20005 and from 2010 to 2015; (2) The quality of ecological environment in Zhejiang Province has declined. the moderate ecological risk area is the dominant type of area, and the high and the extremely high ecological risk areas expand outward. The high value areas are mainly distributed in the vicinity of Hangzhou Bay, the coastal area, and the areas bordering the southwest of Hangzhou, Quzhou and Jinhua. The low-grade ecological risk areas are distributed around the adjacent high-level ecological risk areas and generally spread out in a circular pattern. (3) Land use ecological risk grade conversion varies greatly. The ecological risk shift is mainly from low to high level, and the annual average conversion rate of its ecological risk level is on the rise. Ecological risk conversion mainly occurs in cities and coastal areas such as Hangzhou Bay, Wenzhou, and Taizhou coastal areas where economic development is active. (4) The ecological risk values in the cities of different levels in Zhejiang Province differ greatly in time and space. The city’s ecological risk values mainly show an upward trend, Ningbo’s ecological risk changes the most, and Quzhou City has the smallest change. In terms of spatial distribution, Hangzhou has the highest ecological risk value, which is much higher than other prefecture-level cities. Zhoushan has the lowest ecological risk value.

Taking the east ring road of Erhai in Dali as an example, this paper explored the characteristics of land use change from 1997 to 2015 by constructing the buffer zone and through the models reflecting degree and structure dynamic change of land ues in the region along the road. Results show that: ①With time developing, the land use accelerated its change, thereby reduced differences progressively on the rate of land use change between different buffer zones; ②Forests, bare soil and cultivated land had always been the most dramatic land use types in the study area, the spatial change activities of all land use types became different as the distance to the east ring road of Erhai changed. as time went on, the spatial change activities of the other land types except bare soil became more active within each buffer zone; ③From 1997 to 2015, the overall change of land use types in the study area was significant, in different periods, the main land use change types between different buffer zones were tended to converge, while their differences in all buffer zones became gradually significant over time; ④From 1997 to 2015, the degree of land use in the study area continued to rise but the growth rate had slown down significantly, and the difference of land use degree between buffer zones continued to decrease; ⑤From 1997 to 2015, the land use structure of the study area had been optimized overall, the equilibrium and isotopy of the land distribution both upgraded, and the difference of land use structure between buffer zones had decreased to some extent; ⑥In the past 18 years, the study on the change speed, the growth degree and the structure index of land use and differences of the spatial change activities among various types of land use presented the trend that the high value areas were keeping away from the east ring road of Erhai.

The Three Gorges Reservoir area of Chongqing, located on the upper area of the Yangtze River Basin, is one of the most important biodiversity conservation sites of China. It possesses abundant species and land resources. However, various human activities have directly or indirectly influenced the ecosystem pattern, and consequently the landscape pattern of Three Gorges Reservoir area has significantly changed. Therefore, based on the ArcGIS and FRAGSTATS software, the landscape type map in the Three Gorges Reservoir Area of Chongqing influenced by human activities was obtained through the method of artificial interpretation with the 3 remote sensing images (1995,2005,2015). DMSP/OLS nighttime light stable data was selected to reflect the intensity of human activities, which was divided into 10 levels from weak to strong using the natural breaks method. Besides, the change characteristics of the landscape pattern in different periods within different transects were analyzes, as well as the gradient response of 4 types of landscape pattern characteristics to human activity intensity in 2015. The results were as follows:1) The spatial distribution of human activities was significantly different, which gradually decreases from west to east. In addition, the intensity of human activities in the Yangtze River Basin was obviously stronger than that in the surrounding area.2) At the landscape level, as the human activity intensity increased, the number of landscape patches in the study area was greatly reduced; yet SHDI (Shannon diversity index) and SHEI (Shannon evenness index) first ascended and then descended. In addition, landscape connectivity decreased slightly, and landscape aggregation increased, as well as the fragmentation degree while the situation improved in 2015.3) At the class level, the change of landscape pattern could be well reflected by the 4 main landscape types (construction land, water area, grass land and low density vegetation cover forest land). Especially, PD (patch density), LSI (landscape shape index) and MPFD (mean patch fractal dimension) had significant variations with the gradient of human activity intensity, LPI (largest patch index) and PLAND (percentage of landscape) had a small change except construction land, which indicated that landscape shape was becoming increasingly simplified and regular. PLAND and LPI of construction land reached to 71.2% and 35.72% respectively when human interfered to the most extent. 4) Three Gorges project, the resettlement project, urbanization and the grain for green policy were essential driving forces for the evolution of landscape pattern in the Three Gorges Reservoir area of Chongqing. This study revealed the gradient change of landscape pattern along the intensity of human activities in the Three Gorges Reservoir area of Chongqing in recent 20 years, which could provide references for the rational use of natural resources and sustainable development in the Three Gorges Reservoir area of Chongqing.

In order to provide basis for the regulation of closed fishing seasons and areas, and for protection of germplasm resources, spatial and temporal distribution characteristics of spawning eggs, larvae and juveniles were studied in the Aquatic Germplasm National Reserve of Corbiculafluminea Culter alburnus, Dianshan Lake, from May to August 2016. The results showed that 4463 fish eggs were collected totally, 43012 larvae and juveniles were identified, belonging to 6 orders, 9 families, 19 genuses and 21 species. In addition, the number of individuals caught in fish eggs and in larval fish was approximately 4.16% and 3.98%, respectively. Interestingly, the spawning starts on June 13 while capture is banned on August 17. The relative proportion of the C. alburnus peaked in the mid late July and early August. During the survey, the spawning water temperature was above 25.9℃, and increased to 29.3-34.3℃ during the spawning peak. It is prone that the C. alburnus spawn in clear nights just after rain when the water level rises, and the fish begin to spawn actively when the water level is up to 2 m and other conditions are appropriate. The result also showed that the spawning density of the C. alburnus has a close relation to water temperature and water level (P<0.01). According to the results of the early resources, the collected eggs in artificial fish nests, and the sampled brood brooders in ovulation period, it was concluded that No. 1（Qian deng pu qiao), No. 2(Mei bang), and No. 7(Nan shen bang) waters were the spawning grounds for the C. alburnus.

In the current study, the nine elements in the otolith core elements（Sr, Ba, Mg,Na, Si, Cr, Mn, Ca, Zn）of young-of-the-year （YOY） silver carp collected during August-September of 2012, 2014, and 2016 from the Yangtze River and Ganjiang River were analyzed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). It was showed that the ratios of the four trace elements to the calcium (Sr∶Ca, Ba∶Ca, Si∶Ca, Mg∶Ca) in the otolith core of the YOY silver carp in Yangtze River and Ganjiang River was basically unchanged among the three years from the same river. However, there was a significant difference between the two stocks from Yangtze River and Ganjiang River and the ratios of Si∶Ca and Sr∶Ca made the greatest contribution to stock identification. According to the linear discriminant analysis (LDFA) of the four element ratios, the overall classification accuracy rate of Yangtze River silver carp stock was 92.11%, and the classification accuracy rates in 2012, 2014 and 2016 were 92.31%, 93.33% and 90.91%, respectively. The overall classification accuracy rate of Ganjiang River silver carp stock was 92.31% and the classification accuracy rates in 2012, 2014 and 2016 were 80.00%, 96.77% and 93.75%, respectively. Thus, the four element ratios in otolith core could be used as elemental fingerprints to identify silver carp stocks from the Yangtze River and Ganjiang River. Analysis of otolith microchemistry by LA-ICP-MS will be an effective technique in stock discrimination such as silver carp from Yangtze River and Ganjiang River.

In order to learn the fish diversity in some important branches of Three Gorges Reservoir, the investigation was carried out in the 2015 and 2016  respectively. All important branches can be divided into 4 types: <50 km, 50-100 km,100-300 km, and >1 000 km, and each of them was set to 4, 6, 8, 8 sampling sections respectively. A total of 685.5 kg catches was captured and 35507 samples were measured, 121 species of fish were identified, belonging to 9 order, 22 family and 78 genus, and Cypriniformes and Cyprinidae were the dominated order and family in this research, 68 species were endemic to China, 26 species were endemic to the upper reaches of the Yangtze River, and 9 species were exotic species. The number of total and endemic fish species to China and the upper reaches of the Yangtze River in Xiaojiang River were the largest compared to other rivers, and the Qijiang River followed. The investigation results showed that fish ecological types were mainly viscous eggs, benthic fishes, carnivorous and omnivorous in the study area; there were significant differences in the average taxonomic distinctness Δ+ between rivers greater than 1000 km and others by using t-tests (P<0.05), there were no significant differences in the variation in taxonomic distinctness Λ+ among 4 types of rivers with t-tests (P>0.05), and indicated that there were no significant correlations between Δ+, Λ+ and river length using Pearson correlation test (P>0.05); the main economic fish species included Cyprinus carpio, Carassius auratus, and Pseudobagrus nitidus. In conclusion, taking measures such as prevention introduced species escape and study on artificial reproduction of rare fish should be benefit for protecting fish diversity resources.

Based on the DEA method, this paper estimates the agricultural water use efficiency of 11 provinces in the Yangtze River Economic Belt, then Moran’s I index and spatial econometric model are introduced to analyze the spatial correlation and spatial effect within panel data from 1997 to 2015. The results show that: ①During the study period, China’s agricultural water use efficiency of the Yangtze River Economic Belt shows overall stable rise but imbalance characteristics among different areas, and there is a significant positive spatial autocorrelation between regions.②Regression results of spatial econometric model show that there is a significant spatial spillover effect of agricultural water use efficiency among different areas, indicating local agricultural water use efficiency is affected by both adjacent and non-adjacent areas; in addition to the influence of geographical factors, the similar level of economic development and productivity is conducive to the mutual learning of high-efficiency water use patterns, thereby triggering the spatial spillover effect of agricultural water use efficiency, promoting increase of the overall agricultural water use efficiency.③The high proportion of agricultural water used in the total water consumption will significantly reduce agricultural water use efficiency; the construction of water conservancy facilities and the degree of agricultural mechanization will have a significant positive effect on agricultural water use efficiency.

Remote sensing driven light use efficiency models have been widely utilized to calculate the productivity of terrestrial ecosystems, and the outputs of these models are very sensitive to the values of maximum light use efficiency (εmax). In this study, city-level yield census data, MODIS reflectance data, locally observed meteorological data, and the vegetation photosynthesis model (VPM) were employed to derive annual mean city-level cropland εmax in Huang-huai-hai area (including Hebei, Shandong, and Henan) and the middle-lower Yangtze area (including Jiangsu, Anhui, Hubei, Hunan, and Jiangxi) for the period from 2001 to 2011. Then, the spatial and temporal variations of εmax and possible driving factors were analyzed. The results showed that the average annual value of the city-level means of cropland εmax in Huang-huai-hai area (including Hebei, Shandong, and Henan) and the middle-lower Yangtze area (including Jiangsu, Anhui, Hubei, Hunan, and Jiangxi) varied between 1.8-2.8 g C·MJ-1 during the period from 2001 to 2011. It was higher in the northwest and south parts and lower in the northeast and central parts. Annual mean cropland εmax increased during the period from 2001 to 2011 in most cities, but showed obvious interannual fluctuations and spatial difference in the rising amplitude. The interannual fluctuations of city-level cropland εmax were normally higher in the north than in the south and higher in the central than in the around. The annual means of cropland εmax had strong positive correlation with the amount of fertilizer used in per unit area of cultivated cropland in most cities, and it reached significant level (P<0.05), so the increase of the consumption of chemical fertilizer in these regions was one of the main causes of the increase of cropland εmax. The increase of the yield fraction of C4 crops could also induce the increase of cropland εmax. This study proves that it is of importance to develop a parameterization scheme accounting for the temporal and spatial variations of εmax for improving the calculation of productivity in croplands using light use efficiency models and remote sensing data.

In order to explore the influence of different straw returning modes on carbon footprint in a rice-wheat rotation system, a 2-year field experiment was carried out. In this study, three wheat straw returning modes were set up (wheat straw retuning with rotary tillage, wheat straw retuning with plowing, and wheat straw ditch-buried returning) with no straw returning as the control. The static chamber-gas chromatography method was used to measure greenhouse gases emission and other carbon emissions were calculated by analyzing emissions from the production of main goods and the associated processes during the life-cycle period of rice-wheat rotation. The results indicated that compared with no straw returning, the wheat straw returning significantly increased the average daily CH4 emission and the annual CH4 emission in the rice field accounted for 95% of the global warming potential. In the rice season, the CH4 emission explained the most share of carbon footprint and the wheat straw ditch-buried returning showed the lowest amount among those three wheat straw returning treatments, which was 4.9% lower than that under wheat straw retuning with rotary tillage. In wheat season, carbon footprint derived from chemical fertilizer input was the largest, accounting for 64.5%~77.4%, followed by N2O emission. For the whole rice-wheat rotation, both carbon footprint and yield-scaled carbon footprint under wheat straw ditch-buried returning were the lowest among the straw returning treatments, which was 4.6% and 3.6% lower than wheat straw retuning with rotary tillage, and 8.7% and 4.9% lower than that with plowing. Thus, wheat straw ditch-buried returning might be an effective way to reduce agricultural carbon emission in rice-wheat rotation system.

As the basis of food production, arable land is the root of the survival and development of human society, and its utilization efficiency has profound influence on the development and progress of human civilization. In this study, southwest region in china including Chongqing city, Sichuan province, Guizhou province and Yunnan province as a case study, and based on the dataset in 2000, 2005, 2010 and 2015, the DEA model was used to simulate the efficiency of arable land. Then, the global and local spatial pattern in different period of the arable land use efficiency had been analyzed by the method of global Moran’I, trend surface analysis and G*i index, respectively. At last, the main factors that influence the spatial differentiation of arable land utilization efficiency were evaluated by the method of geography weighted regression (GWR). The results showed that, firstly, between 2000 and 2015, the number of cities in high value areas of arable land utilization efficiency was expanding. Specifically, in the spatial distribution, the efficiency was stable, and the high value region mainly distributed in Dazhou-Deyang-Chengdu-Ganzi in Sichuan province. Sichuan province had maintained high efficiency and changed little; while, the efficiency in Chongqing city increased over time. The efficiency in Guizhou tended to decline, while Yunnan province remains inefficient. Secondly, the efficiency was mainly the positive spatial autocorrelation, and the spatial distribution trend increased from west to east, as well as the increase trend of the “U” pattern from south to north. Remarkable comprehensive of efficiency spatial pattern of differentiation, and relatively higher value/lower value of efficiency presented strong aggregation depended on the space distribution, cold/hot spatial pattern polarization phenomenon more obvious, clearly line and hierarchy. Change over time, the region of cold/ hot spots on the spatial pattern had changed from the “group” pattern to the “tape” pattern. Thirdly, the spatiotemporal change of the arable land utilization efficiency was the largest affected by driving factors of the per capita net income of farmers, followed by the multiple crop index; the effect of cultivated land quality and irrigation index was similar; the influence of per capita GDP to cultivated land use efficiency increased year by year; while, the effect of terrain factors decreased year by year.

The sediment deposition, water erosion and bank collapse will have a great influence on the shape of Jiangxin island, the reclamation of tidal flat, the change of channel and the ecology of estuary. In this study, Yangzhong, the second large island of the Yangtze River is taken as the research object. The erosion and siltation along the river bank of Yangzhong during 1973 and 2017 and the bank collapse in 2017 are monitored by remote sensing images. Furthermore, the reasons of dynamics are discovered by combining multiple data. Results show that: (1) the erosion and siltation along the river bank of Yangzhong are divided into three stages and characteristic differences of different stages are obvious; (2) after position identification, the bank collapse of Yangzhong is located in the intersection of two ancient rivers. One of them is on the right side of Taiping Island, the other is nearby it and in the southwest to northeast direction; (3) There is no obvious relationships between bank collapse and water erosion. Blocked ancient river outlets generate water pressure and grooves in river bottom induce rotational water flow then carry off sediment. In addition, river discharge after flood season aggravates the water pressure and then results in bank collapse directly.

Hydrological connectivity possesses both natural and social attributes, but comprehensive reviews are scare about this issue. This paper firstly illustrates the definition and classification of hydrological connectivity. Secondly, the quantitative methods of lateral hydrological connectivity are generalized. Finally, the Dongting Lake is taken as an example to introduce the gradual changes of river-lake relation due to human disturbances. Concerning on this problem, the paper explores some measures that can be taken in the future. It is suggested to build a response model which considers the comprehensive influence of water and sediment changes, and the evolution of river-lake relation under human disturbances and climate change. In addition, effective engineering methods should be designed to enhance the ecological health and strengthen the management of rivers and lakes.

The hydrologic regime has undergone significant and long-term adjustment in the Hanjiang River basin, which is the water head site of Central Line Project of South-to-North Water Diversion. It is key to explore hydrometeorological trends and driving forces for sustainable utilization of water resources and formulation of reasonable water resources management policies. In this paper, the double mass curve method, the accumulative anomaly method and the Mann-Kendall method were used to analyse the hydrometeorological data for the nearly 50 years in the Hanjiang River basin. Results indicate that the annual rainfall in the upper and lower reaches of Hanjiang River shows an increasing trend, but shows a decreasing trend in the middle reaches. Annual average temperature and evaporation increase in the whole basin. From 1965 to 2016, water resources could satisfy the needs for human activities in the upper reaches of the Hanjiang River, while failing those in the middle and lower reaches of the Hanjiang River, despite steady rise in demand since 1977. Two inflection points, 1990 and 2010, were identified, according to which the based period, aberrant period Ⅰ and Ⅱ were divided. Utilizing the slope change ratio of the fitted beeline between year and accumulative quantity, the contribution rates regarding the influence of the fluctuation in climate and human activities on the upper reaches and whole basin is 26.1%, 73.9%, 33.8%, 66.2% in aberrant period Ⅰ, and 19.3%, 80.7%, 43.7%, 56.3% in aberrant period Ⅱ, respectively. The human activities are the main driving force of runoff change, and the effect of that on runoff in the upper reaches of the Hanjiang River is greater than that in the whole basin. In aberrant period Ⅱ, the influence of human activities on the runoff in the upper reaches of the Hanjiang River increase by 6.8%, while that in the whole river basin decrease by 9.9%.

Based on the daily precipitation data during 1961-2016 of 32 stations in Hanjiang river basin, the spatial and temporal distribution characteristics of precipitation are analyzed, and the impact of sea surface temperature and atmospheric circulation on the precipitation in Hanjiang river basin are discussed. The results show that: The spatial distribution of rainfall is similar to that of rainy days of each grade, and the rainfall and rainy days of light rain and moderate rain gradually reduce from the southwest to the northeast; The precipitation centers are located in the southwest and the southeast, and there are more rainfall of heavy rain and above in the northeast; But the rainfall intensities of each grade have no obvious regularity; The PCD increases and the PCD postpones gradually from the southeast to the northwest; There are differences between driving factors of seasonal precipitation; In the aspect of the impact of sea surface temperature on seasonal precipitation, spring precipitation has a negative correlation with the Southwest Indian Ocean sea surface temperature from last November to February, summer precipitation has a positive correlation with the tropical North Atlantic Ocean sea surface temperature from February to August, and autumn precipitation has a negative correlation with the tropical Central-eastern Pacific Ocean sea surface temperature from April to September, but winter precipitation is little affected by sea surface temperature; And in the aspect of the impact of large-scale atmospheric circulation on seasonal precipitation, spring precipitation is related to western Pacific teleconnection pattern, summer precipitation is affected by the position of western Pacific subtropical high and the Ural blocking high, autumn precipitation is related to the India-Burma trough and the low trough of Balkhash Lake, and winter precipitation is influenced by the Eurasian teleconnection pattern; Therefore, atmospheric circulation changes the East Asian winter monsoon intensity to impact on the precipitation in spring and winter and meeting location and intensity of cold air and warm and wet air to influence precipitation in summer and autumn.

In order to establish a watershed eco-compensation mechanism with fairness and efficiency, calculate eco-compensation amount scientific and reasonable, an eco-compensation model of river basin transboundary based on emission rights are constructed from the angle of economics. Taking the Minjiang River Basin in Fujian Province for example, theoretical emissions and the loss of emissions in 2011-2015 were calculated, and the amount of eco-compensation was checked. The results indicated that the total amount of eco-compensation in each city exhibit obvious annual variations. As the downstream city of the Minjiang River Basin, the total amount of eco-compensation in Fuzhou was based on the discharge of pollutants in the upstream cities of Nanping, Quanzhou and Ningde. Nanping and Sanming cities are located on the middle reaches of the Minjiang River Basin, The total amount of eco-compensation was determined by the upstream cities and their own water pollutant emissions. As the upstream city of the Minjiang River Basin, the total amount of eco-compensation in Quanzhou, Longyan and Ningde cities was mainly based on their own pollutants. According to this eco-compensation calculation results, the writers put forward suggestions to improve the River Basin eco-compensation mechanism: specifying the subject and object of eco-compensation; giving consideration to both upstream area and downstream area interests; establishing the regulations of river basin pollution rights.

近年来，城市内涝问题日益突出，严重影响着城市的可持续发展。运用合肥市气象数据、地理信息数据、社会经济统计数据以及历史内涝灾情数据，基于二维非恒定流水动力模型（FloodArea），开展城市内涝灾害风险评估与预警技术研究。研究表明：根据城市内涝预警业务需求，综合暴雨强度公式和广义极值分布两种方法，推算出合肥市1、3、6、12、24 h下5、10、20、30、50、100 a一遇的降水量，应用FloodArea模型模拟得到不同历时下多个重现期的淹没水深图谱，耦合精细化的承灾体信息及脆弱性曲线，完成合肥市城市内涝风险评估，再结合强降水预报，开展城市内涝风险预警业务应用；由典型内涝过程的效果检验可知，风险评估结果与灾情调查数据较为吻合、可靠度高，进而建立了降水预报→淹没模拟→风险评估→预警发布→效果检验一套较为完备的城市内涝风险评估与预警业务流程，可用于城市内涝实时风险评估与预警业务。

Due to the influence of global climate change and severe human activities, the frequency and intensity of urban flood disasters in basin are increasing frequently. Because of various urban development of cities in the Poyanghu Basin, the land use structure was forced to change. Because of the rapid urban development in Poyanghu Basin, the land use structure changes continuously. Meanwhile, some unreasonable land use type increased the risk of flood disaster. It’s significant and necessary to study and reveal the spatial-temporal distribution of the flood risk in the different basin. The study can be used as a support tool to help local stakeholders make future flood risk prevention and reduction planning, and flood disaster management. In this study, the urban region of Jingdezhen City in Poyanghu Basin was selected as the study area. Firstly, the formation of flood risk and the causes of flood disasters in cities of basin were analyzed. Secondly, based on the formation process of urban flood risk in Basin, the assessment index was set up from four main aspects (disaster-causing factors, disaster-pregnant environment, disaster-bearing body and the prevention and mitigation ability). Thirdly, a small-scale flood disaster risk assessment model was developed based on Analytic Hierarchy Process(AHP) and Geographic Information System(GIS). Finally, taking the urban area of Jingdezhen as a case, the spatial risk was calculated quantitatively. And the adjustment strategies of land use type in the typical flood disaster affected areas were put forward according to the spatial-temporal distribution of flood disaster risk. The results showed that there was a big difference between the maximum and minimum values of flood disaster risk in urban areas from the perspective of space. The risk decreased gradually from the center line of Urban River to the surrounding. The range of risk volatility in different regions was different. The Changjiang coastal area of Zhushan District which has high social and economic development level were the high-risk areas and the risk level was low in western, southwest and eastern towns. From the perspective of time, the maximum value of flood disaster risk in the urban city decreased from 2010 to 2013 while the local areas of high flood disaster risk were more concentred. The risk of flood disaster in the South became smaller as a whole. The value of flood disaster risk in the western part of the city increased slightly. According to the different regional characteristics, two hypothetical adjustments were adopted to change the land use types in the typical flood areas in the basin. After calculating the average value of flood disaster risk, the value of flood disaster risk in two regions decreased from 0.606 and 0.610 to 0.561 (7.4%)and 0.571(6.4%) respectively.

Through the collection and collation of the historical literature on drought and flood disasters in the Pearl River Basin from 1644-1911, the drought and flood level sequence of 268 a was reconstructed by the affected county. The temporal and spatial characteristics of the drought and flood sequence were analyzed by means of sliding average, cumulative anomaly, EEMD and IDW. The results show that the droughts and floods in the Pearl River Basin were frequent in the Qing Dynasty from 1644-1911, and the frequency of disasters was slightly more than that of droughts. The droughts and floods in the Pearl River Basin from 1644 to 1911 can be divided into three drought periods and two hemiplegia periods: 2 a and 5 a for the interannual change, 10 a and 24 a for the interdecadal change, as long as 134 a for the century change. In the Qing Dynasty, the flood-stricken disasters in the Pearl River Basin have obvious differences in spatial ratios, and overall flood disasters are more than drought disasters. The spatial distribution of drought disasters in the Pearl River Basin is uneven, and the overall decline from east to west. The frequency distribution of flood disasters is regionally connected, mainly in Guangdong, Jiangxi and central Yunnan.

The time series of hydrometeorology has lost its consistency, because of the influences of climate change and human activities. Based on the daily temperature data during the period of 1960-2013 in 89 meteorological stations over Hunan Province, the annual mean maximum temperature (AMMT) and peak over threshold (POT) are selected to detect the inconsistent characteristics of the extreme high temperature indices. The results showed that there were significant inconsistencies in the AMMT series of 59 sites (66.3%) and the POT series of 23 sites (25.8%) out of 89 stations. The parameters of five extreme distributions GLO, GEV, GPA, GNO and PE3 are estimated by using the L-moments method. From the results of Cramer-von Mises (C-M) test, we found that the GNO distribution function can better fit the series of extreme high temperature indices in Hunan Province. The non-stationary series is modified by the reduction pathway. Based on the GNO model, we calculated the estimated return levels for both the modified and non-modified extreme series at different return periods and assessed the changes of the extreme series at three different return periods. Under the conditions of climate change, the AMMT series showed an enhanced trend of intensity and a shortened trend of the return period in north Hunan, central Hunan and southeast Hunan. However, the POT series showed similar frequency characteristics variation only in northern Hunan and southeastern Hunan.