The urban-rural integrated development is the key measure to realize rural vitalization and promote new-type urbanization, while the land market is an important channel to realize the flow of urban-rural development elements, also a key link to connect urban-rural development. This paper analyzes the scientific connotation and substantial characteristics of urban-rural integrated development, and then explores the driving mechanism of land market on urban-rural integrated development. Based on these foundation, we quantitatively analyze the evolution law of land market and urban-rural integrated development in 273 cities at prefecture level or above in China. Furthermore, the relationship between land market and urban-rural integrated development was tested based on the panel data model to give a feasible proposal for the integration of urban and rural development from the perspective of land market. Main conclusions are drawn as follows: (1) The urban-rural integrated development is a process of the reconstruction of urban-rural values aiming at removing the obstacles hindering urban-rural development. It helps to promote the free flow and equal exchange of urban-rural elements, and achieve the convergence of returns from urban-rural development elements. The essence is to achieve the overall optimization of urban-rural regional functions through urban-rural integrated development and complementarity. (2) The effect of land market on urban-rural integration is a balance of advantages and disadvantages, and the direction depends on whether the land market is benign. Under the urban-rural dual distribution system and the curtain wall of society, the distorted land market impedes the urban-rural integrated development. (3) From 2005 to 2013, the scale of land market, land market price and land marketization degree increased by 113.66%, 274.09% and 37.07%, respectively, while the level of urban-rural integrated development in 59.34% cities have declined. Steadily developing land market and low level of urban-rural integrated development in China presented stark contrast and obvious spatio-temporal differentiation. (4) Currently, land market is more of a hindrance to urban-rural integrated development, but there is a "low level trap" between land market and urban-rural integrated development. Breaking the suppression inflection point of 88.64%, land market can then play a positive role on promoting urban-rural integration. So, reshaping the healthy value orientation of the land market development, accelerating the land marketization reform and exploring the mechanism of population-land linkage are important parts for follow-up work.
To discuss how off-farm employment affect the harvesting decision-making of households with different scales in China's collective forest area is valuable to clarifying the forest management objectives for households and the trend of forest management ownership in collective forest area. This can give evidence for supporting the large-scale forest ownership under the background of the fast growing of out-migration rural labors in China. Based on the theory of New Economics of Labor Migration (NELM), this paper collected the input-output data at plot level of Chinese fir management through a survey of 50 rural households in Zhejiang, Fujian and Jiangxi provinces. Then, it calculated the optimal rotation age of large- and small-scale households with the Faustmann model, and used the econometric model to analyze how off-farm employment affect the harvesting decision-making of households with different scales. The results show that there is no obvious difference of optimal rotation age between large- and small-scale households. The migration effect of off-farm employment causing the expect rotation age is obviously smaller than optimal rotation age for small-scale households; on the contrary, the income effect of off-farm employment caused the expect rotation age is significantly closely related with optimal rotation age for large-scale households. Large-scale ownership is more suitable for raising large timbers and increasing economic and ecological value in collective forest area under the fast growing of out-migration rural labors in China.
Water resources cooperation is one of five key priority areas of the Lancang-Mekong Cooperation (LMC) and is also the flagship field that LMC members will value most. Sanya Declaration of the First Lancang-Mekong Cooperation (LMC) Leaders' Meeting agreed to enhance cooperation among LMC countries in sustainable management and utilization of water resources such as technical exchanges, capacity building, drought and flood mitigation, data and information sharing, as well as conducting joint research and analysis related to resources of the Lancang-Mekong River Basin (LMRB). The paper firstly analyzed the current situation and defects of water resources cooperation mechanisms in the LMRB. At present, cooperation mechanisms are dominated by extra-regional countries with prominent conflicts of interest, and lack the participation of upstream countries, which generally focuses on the economic fields instead of on water resources. Then, we review the frame structure and the latest advances of the Water Resources Cooperation of LMC. Several levels like Leaders' Meeting, Foreign Ministers' Meeting and Joint Working Groups on water resources were established to promote cooperation in the LMC countries. Water resources cooperation has accelerated its pace based on the above structure, and a series of significant meetings and dialogues have been held. What is more, we summarized its advantages compared to current water resources cooperation mechanisms in the LMRB. The level of the cooperation is high under the leadership of heads of state and government of the LMC countries. Meanwhile, the fields of cooperation should be deepened in an all-round way. The cooperation mechanisms are associated with the countries in the whole basin and need to be built on a solid foundation. At last, some suggestions were given to improve and reinforce water resources cooperation of LMC, including strengthening consultation and coordination between Joint Working Group on Water Resources Cooperation of LMC and other Joint Working Groups, setting up a special fund to support water resources cooperation and constructing cooperation network Think Tanks.
To study the rationality of tourism development model in forest parks can provide important bases for improving the utilization efficiency of forest tourism resources and protecting forest resources. This article uses the Cobb-Douglas production function to determine the type of the tourism growth model in forest parks at the provincial level and analyzes the effects and utilization efficiency of tourism resources in the tourism growth process of forest parks in perspectives of the "resource comparative advantage" and "resource utilization rationality". The main findings include: (1) The average contribution rates of capital investment, labor input, tourism resource endowment and generalized technological progress in forest parks are respectively 0.5132, 0.1712, 0.0697 and 0.2457 during the period from 2004 to 2014. There are five types of "capital-related-driven tourism growth model" in 24 provincial level areas (hereafter provinces). There are four types of "generalized technological progress-related-driven growth model" in 21 provinces, mainly in the central and western regions. There are only two types of "tourism resources-related-driven growth model" in 3 provinces. (2) In the process of tourism growth in China's forest parks, there is not only a phenomenon of redundant capital investment, but also a phenomenon of insufficient utilization of tourism resources. The utilization of tourism resources in some provinces is unreasonable due to excessive capital investment, which directly leads to "over-utilization of tourism resources" and "underutilization of tourism resources". The analysis shows that tourism resources in 19 provinces have not been rationally utilized. Among them, the tourism resources in 8 provinces are over-developed, dominated by the eastern coastal and central provinces, and the tourism resources in 11 provinces are underutilized, which is mainly in the southwest and northwest regions. In addition, only the forest tourism resources in 12 provinces such as Beijing, Tianjin and Shanghai can be developed and utilized reasonably. (3) There exists incomplete matchable development status among tourism resource endowment, comparative advantage of tourism resources and rational utilization of tourism resources due to the difference of capital investment in each province. The comparative advantages of tourism resources in the provinces with poor tourism resources are mostly at the intermediate level, but the state of resource utilization is mostly insufficient. The comparative advantage of tourism resources in provinces with medium tourism resources is mostly at a low level. Meanwhile, the provinces with rich tourism resources are generally those with a large amount of resources, but the state of tourism resource utilization is uncertain.
Land use change analysis at different periods has been very helpful for resource management and essential trends detection through time. In order to understand the changes of land use, we examine the level of land use and the strength of human activities on land use in the Yellow River Basin in recent years. Based on the analysis of the change of land use area in the study area, according to secondary divisions of water resources, importance index of land use change (Ci), proportion of land use change area (D) and vegetation index of forest and grassland (R) were used to analyze the direction and degree of land use change in eight regions of Yellow River Basin during 1980-2015. It is found that land use in this basin underwent significant changes in the 35 years. The intensity of land changes in the Hekouzhen-Longmen section of the Yellow River Basin was the most intense. Although the degree of change in the eight sub-regions was relatively small, the absolute change area was large. The speed and degree of land use change were studied in four periods of 1980-1990, 1990-2000, 2000-2010 and 2010-2015 by using single land use dynamic degree, comprehensive land use dynamic degree and land use degree. The results showed that compared with 1980, the area of built-up land and water changed significantly. By analyzing the rate of single land use change in different periods, the rate of desert and unused land, water and urban and rural industrial and residential land changed significantly. The other three types of land use were not noticeable because of larger base area. In terms of the study periods, the change rate during 2010-2015 was the highest, and presented an increasing trend over time. Through the analysis of land use change rate, there was an increasing trend in all the eight regions; however the increasing trend in Longyangxia region was the most obvious. Except Longyangxia and Huayuankou water resources divisions, the comprehensive index of land use degree in the entire Yellow River basin ranged from -2 to 2 from 1980 to 2015, indicating that the comprehensive level of land use in each division did not change much in this period. From this perspective, human activities have less impact on land use. The reason for this result is that the entire area of the Yellow River Basin is too large, and the areas with intense human activities are only distributed in densely populated towns and plains. In the 35-year period, human activities did not have a profound impact on forests, grasslands, and deserts.
Land cover change (LCC) is an important part of global change study and sustainable development research. Accurately describing the process of land surface change at the national scale is a necessary step in the study of the relationship between man and nature. The analysis of land cover change of Democratic People's Republic of Korea (DPRK), a hot developing country of concern to the international community, will be a key point to lay a foundation for the sustainable utilization of land resources and ecological environment protection in Northeast Asia and cross-boundary region of China. In this study, Landsat TM/OLI images of DPRK in 1990 and 2015 were used to extract the information of land cover by using object-based images analysis (OBIA) and some statistical data were used to analyze the driving forces of land use change in DPRK. The results showed that forestland (-4976.1 km2) and cropland (+4821.5 km2) were the most obviously changed land cover of DPRK in the 25 years. Wetland decreased by 212.2 km2, while built-up land increased by 82.8 km2. Among various land cover changes of DPRK, the expansion of cropland converted mainly from montane forest (94.6%) were essential and fast. The conversion between forestland and cropland significantly occured in sloping fields with relatively high elevations (100-1000 m) and intermediate slope gradients (8°-35°). In the meantime, the changed area of wetland and built-up land were mainly found at lower elevation (0-100 m and 0-200 m) areas which were nearly flat (0-8°). North Hwanghae, with a change rate of 17.3%, was the most obviously changed district, followed by South Pyongan. Land cover change of Ryanggang was least apparent with a change rate of 2.2%. DPRK has been suffering from the economic downturn and worsening natural environment since the 1990s, and its land cover changes were influenced mostly by human factors such as the growth of population, the deterioration of economic environment and the regulation of national macro-policy.
Using the panel threshold model proposed by Hansen, this paper empirically studies the nonlinear relationship between economic globalization and ecological footprint based on panel data of 55 countries along "The Belt and Road" from 1993 to 2013, with economic development level (per capita GDP) as the threshold variable. The results show that there are distinctive relations between economic globalization and ecological footprint divided by thresholds rather than a single linear relationship. In different ranges of thresholds, the influences of economic globalization on ecological footprint are different. When the economic development level is less than per capita ${$}$ 3905, the improvement of economic globalization can effectively reduce the ecological footprint; when the economic development level exceeds the first threshold of per capita ${$}$ 3905, its improvement has positive effect on the ecological footprint, but the coefficient is not significant; when it exceeds the second threshold of per capita ${$}$ 8778, its improvement will increase the ecological footprint significantly. Currently, countries along "The Belt and Road" are mainly concentrated in the first and third threshold interval, and the influence of economic globalization on the ecological footprint has a polarization trend. Attention should be given to the countries in the third threshold interval in the process of globalization, which is closely related to many aspects in sustainable development of globalization and "The Belt and Road Initiative".
Starting from the concept of strong sustainability, we measure the green innovation efficiency and ecological welfare performance of 30 provinces in China from 2004 to 2015 based on the improved SFA model. We analyze the degree of the coupling coordination of the two systems with a coupling-coordination model, taking into account their spatial characteristics and evolution rules. The results show that: (1) China's ecological welfare performance value has been spatially supported by a quadrangular pole composed of Beijing, Zhejiang, Guangdong and Shaanxi, and continues to radiate to the areas along the lines. (2) The average coupling degree of the two systems in 2004-2015 is C∈ [0.666, 0.680], which is in the stage of high intensity coupling, while the average coordination degree is in the stage of elementary coordination (D∈ [0.512, 0.565]), meaning that there is still large improvement space in the future. (3) In terms of spatial pattern, there is a significant gap in the degree of coupling coordination between different regions. The high-value areas (midium- and high-level coordination) are mainly concentrated in the eastern coastal areas, and have formed a "U"-shaped development axis of polar nuclear radiation coordination between Guangdong and Zhejiang. At the elementary coordination stage, the trend of connected regional expansion is obvious. In comparison, the northwest region is still in the final echelon of the coupling coordination between China's green innovation efficiency and ecological welfare performance. It is less affected by the radiation from the surrounding areas and the growth rate is slow.
The continuous degradation of ecosystem services is a common challenge facing human-beings, and it is the focus of global sustainable development research. The ecological environmental protection in the Middle Yangtze River region is of great significance to the construction of ecological security pattern in China. In order to deeply analyze the interference degree of land use activities to ecosystem services value (ESV) in the Middle Yangtze River region, it is necessary to evaluate the spatial-temporal distribution of ESV and the sensitivity of ecosystem services to land use change in the study region. Based on the evaluation results of ESV in the Middle Yangtze River region, this paper constructed the ecological contribution model of land use change and ecosystem services sensitivity model. The results showed that: (1) The average ecosystem service value (AESV) in this region in the years of 1995, 2005 and 2015 was 46244.29 yuan/hm2, 46484.08 yuan/hm2, and 46249.254 yuan/hm2, respectively, and the study region experienced a "first increase and then decrease" change process. The counties with higher AESV were mainly located in the mountainous areas; plain areas, urban agglomeration areas, Wuhan, Changsha, and Nanchang, and major traffic routes tended to have lower AESV; the ESV change rate presented a spatial pattern of "two horizontal and three vertical" distribution. (2) The conversion of cultivated land to forest land and cultivated land to water areas during 1995-2015 were the key factors for the improvement of regional ESV, and their ecological contribution degrees were 33.34% and 32.99%, respectively; forest land converted to cultivated land, forest land converted to construction land and cultivated land converted to construction land were important causes that induced the deterioration of the regional ecological environmental quality, and their ecological contribution degrees were 36.21%, 20.26% and 11.98%, respectively. (3) The ecosystem services sensitivity areas were mainly distributed in areas with frequent human activities, 1% increase in the integrated land use dynamics would result in 0.18% and 0.15% fluctuation in ESV in the Middle Yangtze River region during the periods of 1995-2005 and 2005-2015, respectively; the ecological sensitivity of food production, raw material production, gas regulation, soil conservation and maintenance of biological diversity increased, and the sensitivity of other ecosystem function gradually weakened during the two study periods. The results of this study can provide scientific implications for the ecological environmental protection and the continuous supply of various sub-functions of the ecosystem services in the Middle Yangtze River region.
With the continuous diversification of people's dietary demand, sustainable food consumption has become a global concern. In order to explore sustainable food consumption patterns, this study first analyzed the evolutionary trend and characteristics of Chinese food consumption structure. The environmental stress tendency of Chinese food consumption was assessed by using the ecological footprint model. A measurement standard for dietary ecological carrying level was introduced based on the connotation of sustainable food consumption, Chinese balanced diet and environmental sustainability indicators. Then the study established a sustainable food consumption pattern that conforms to Chinese food consumption habits, meets the nutritional intake demand, and reduces sufficiently the environmental stress. The results show that the dietary environmental stress continued to increase in China. Per capita ecological footprint of Chinese food consumption increased by 154.49% from 1978 to 2013. Ecological deficit appeared in 2008 and it was 0.0705 ghm2 in 2013. Dietary ecological carrying level continued to deteriorate. Annual ecological carrying level dropped from "higher" to "medium" in 2008. The established sustainable food consumption pattern reduces per capita ecological footprint by 12.92%, which indicates that transforming food consumption pattern is the most effective way to solve the contradictory problem of dietary environmental stress.
There is huge spatial disparity between Chinese electricity production and consumption. Most of coal, hydropower, wind and solar power resource are distributed in western provinces while population and industrial activities are agglomerated in eastern provinces, which lead to a huge amount of inter-provincial electricity flow and trade to realize supply-demand balance. Based on the annual reports of the State Power Market Trading and the China Energy Statistical Yearbook, etc., this paper established the inter-provincial electricity O-D flow matrix for 2006 and 2015 with a degree of interpretation over 95%. Then, taking the influence, extroversion, acceptability and dependence degree as main indicators, this paper analyzed the scale and strength of output and input points of 25 provincial administrative units and 2 regional units in China. The source and sink points of the inter-provincial electricity flow were determined, their field characteristics were studied, and the differences between the two years of 2006 and 2015 were compared. Further, the characteristics and changes of the spatial structure of inter-provincial electricity network were analyzed with the method of network analysis. At last, some conclusion can be drawn as follows.
Firstly, with the development of coal-fired and wind-based clean energy bases in the northwest region and the vigorous development of hydropower resources in the southwest region, the surplus of electricity in the western region has grown rapidly. China's electricity source points gradually shifted from the central to the western region and more concentrated in southwest region. Inner Mongolia, Sichuan and Yunnan became the top three source points of Chinese electricity flow with the proportions of outward electricity to total being more than 10%. Also, their proportions of outward electricity to production were all more than 30%, which means that nearly one-third of electricity was produced for other users. On the other hand, three most prosperous metropolitan regions in China, namely Beijing-Tianjin-Hebei, Shanghai-Jiangsu-Zhejiang and Guangdong, were still the main sink points with their proportions of inward electricity to total being more than 20%. Secondly, the spatial disparities of the electricity production and consumption increased, leading to the increase of sizes of the source output and the sink input. Also, the scale of inter-provincial electricity flow and network contact density showed an increasing trend. During this period, the size of interprovincial electricity flow increased 3.1 times and the inward electricity flow of Jiangsu-Shanghai-Zhejiang, Guangdong and Beijing-Tianjin-Hebei increased 5.0, 3.4 and 2.3 times, respectively. Thirdly, the inter-provincial power flow field presented a significant three-channel pattern of "West-to-East Power Transmission" from north to south, which was affected by geographical location and subordinate regional power grids. From 2006 to 2015, this pattern of three major channels remained unchanged. Further, with the development and application of UHV technology in China, long-distance power transmission became possible so that some large electricity input points can rely on multiple sources of power instead of a single source. Therefore, the inter-provincial electricity network tends to be perfect and balanced in the future.
The abnormal first frost date and last frost date that occur in the critical period of crop growth will cause great losses to crop yields. It is of great significance to know and grasp the changing rules of abnormal frost date index accurately in the Huaihe River Basin to ensure the stable, high and safe grain yield of China. Ground 0 cm daily minimum temperature collected at 61 meteorological stations were used to identify the first and the last frost dates. The standard deviation was used to calculate the stability of the first and the last frost dates and the probability density function was used to define abnormal first and last frost dates. Meanwhile, IDW interpolation method was adopted to reflect the stability of first and last frost dates and the frequency of abnormal frost date before and after the transition of climate state. Moreover, linear trend estimation, Mann-Kendall mutation test, sliding t-test and cumulative averaging method were employed to obtain the mutation year in temperature. And the effect of the circulation index and air temperature on the first and the last frost dates was analyzed by correlation coefficient method. The following conclusions can be drawn from the analysis above: (1) The mean temperature of Huaihe River Basin in the period 1960-2015 showed a significant upward trend at a rate of 0.18 ℃·10 a-1 (P<0.01) and the mutation year happened in 1993. The transition of climate state promoted the postponement of the first frost date and the advancement of the last frost date. (2) The transition of climate state led to the decrease of the stability of first and last frost dates. The stability of first and last frost dates became much better with the increase of latitude and longitude. The stability of the first frost date became better with the increase of elevation. But the change of the last frost date is not significant even when the elevation increases. The stability of the last frost date is better than that of the first frost date. (3) There was a descending order among the frequency of earlier first frost date, later last frost date, special early first frost date, and special late last frost date. And after the transition of climatological state, the frequency of abnormal first and last frost days tends to decrease and be stable at 0-20%. On the whole, the frequency of abnormal first frost date is higher than that of abnormal last frost date. The impact of climate warming is greater on the first frost date than on the last frost date. (4) The spatial distribution of abnormal first and last frost dates was significantly different, the high frequency of which was observed in the 1970s and the 1960s, respectively, and the low frequency of which was found in the 2000s. Although the frequency of abnormal first and last frost dates was gradually stabilized and remained at a low level, the transition of climate promoted the increase of the frequency of special early first date in the southeast and south parts, partial early first frost date in the south, partial late last frost date in the northeast, and special late frost date in the southeast of the Huaihe River Basin respectively. (5) The smaller the polar vortex area is in September in the northern hemisphere, the later the first frost date is (R=-0.41, P< 0.01); the smaller the polar vortex area is in February, the earlier the last frost date would be (R=0.29, P<0.01); the larger the subtropical high is in October, the later the first frost date is (R=0.39, P<0.05); the larger the subtropical high is in April, the earlier the last frost date is (R=-0.15, P>0.05). Moreover, the tendency ahead of schedule was accelerated after 1990. The result of this article is good for frost forecast services and mitigation of frost disasters.
The middle and lower reaches of the Yangtze River serves as an important grain production base in China. In the context of global climate change, the drought events will directly affect the agriculture production and people's properties and lives in this region and also the national food security. In this study, the meteorological drought events have been extracted using run theory based on the standardized precipitation index (SPI), which is defined using the gridded dataset of monthly precipitation with a spatial resolution of 0.5°×0.5° in China from 1961 to 2015. The drought events are characterized by three variables including duration, severity and peak. Exponential and Gamma functions are then selected to describe the marginal distribution of drought duration and severity, respectively. The Clayton Copula is used to construct the joint distribution of drought duration and severity. Based on the above functions, conventional univariate frequency analysis and copula-based bivariate frequency analysis are used to characterize the spatial patterns of the drought events in the study area at various time scales over the past 55 years. While univariate analysis is focused on return levels of selected return periods (5-, 10-, 20-, and 30-year) for the SPI of 3-, 6-, and 12-month time scales, the bivariate analysis is focused on the joint occurrence probabilities P1 and P2 of drought duration and severity, where P1 is the probability of "drought duration and severity" exceeding their respective thresholds at the same time and P2 is the probability of "drought duration or severity" exceeding their respective thresholds at the same time. Here, the thresholds denote the duration and severity values corresponding to selected 5-, 10-, 20- and 30-year return periods. The results show that: (1) There are some differences between the spatial patterns of drought characteristics for the 3-month, 6-month, 12- month time scales in the middle and lower reaches of the Yangtze River, and the most serious droughts mainly occur in the lower reaches of the river. (2) Both drought duration and severity are positively correlated at various time scales, that is, the areas with higher drought severity are also associated with longer drought duration and vice versa. (3) Poyang Lake watershed and areas north of the lower Yangtze River are associated with larger values of the joint occurrence probability P1, that is, when the drought duration and severity exceed their corresponding 5, 10, 20 and 30-year return values at the same time, while smaller values of the joint occurrence probability P1 are noted for Southern Shaanxi, Southern Henan, a major portion of Hubei and central-north of Hunan, suggesting a low risk of droughts in these areas. The results of this study can provide theoretical basis for scientific managements of water resource and the risk assessments of drought disaster in the middle and lower reaches of the Yangtze River.
The transformation of the function of sloping farmland, and the mechanism of this process are of great significance to studies on the future food security and ecological security in the Three Gorges Reservoir area (TGRA). This study, based on 0.51 m high resolution remote sensing image data, took the Caotangxi watershed as the study area. Combined with field investigation, we visualized the spatial shape of sloping farmland function transformation by analyzing the conversion of sloping farmland into economic fruit forest. Then we discussed the conversion of agricultural land use in the study area and revealed the internal mechanism of sloping farmland function transformation in the TGRA. Research showed that: (1) Around 2012, the focus of farmland-fruit forest conversion in Caotangxi watershed transferred from low altitude plain in the southwest to high altitude and sloping farmland covered areas in the northeast, with the 800-m elevation as the inflection point. And the change points are within the slope of 15°-30°. (2) The aggregation of the farmland-fruit forest conversion in the study area generally occurred at about 8.5 km characteristic scale, and the spatial distribution was more balanced with time. (3) The phenomenon of farmland-fruit forest conversion was closely related to human activities, and occurred mostly in the vicinity of rivers, roads and rural settlements. (4) The farmland-fruit forest conversion could be summed up as 6 change patterns on the micro and macro scales. Driven by social, economic and natural factors, the farmland-fruit forest conversion in the TGRA is essentially the sloping farmland function transformation, and the focus tended to be a win-win situation of economic and ecological benefits.
The validation of LAI products not only provides quantitative quality description, but also plays an important part in the improvement of retrieval algorithm and understanding of uncertainties regarding to land surface process models over rugged surfaces. This study evaluated the performance of MODIS (C5, C6), Geoaldn2 (GEOV1, GEOV2) LAI products using intercomparison methods over Southwestern China. The spatiotemporal distribution of integrity and consistencies, such as the percentage of main algorithm, smoothness index, average value during growing season, yearly mean LAI bias and root mean square error (RMSE), respectively, were investigated during the period 2001-2016. Meanwhile, different versions of the same data source LAI products were compared so as to get a clear understanding of improvement about the new one over heterogeneously hilly regions. Lastly, four factors, such as topography (altitude and relief amplitude), vegetation types, and climate regionalization were selected to assess the influence of different underlying surfaces on LAI products using the Geodetector. The results show that spatial and temporal consistency of these LAI products is good over most areas. All LAI products exhibit a higher percentage of good quality data (i. e. successful retrieval) in mountainous areas, and GEOV2 LAI is higher than others. The percentage in altitude and higher relief amplitude area seems to be low. GEOV2 LAI shows smoother temporal profiles than others, and Geoland2 is smoother than MODIS LAI. It is clear that MODIS C5 is smoother than MODIS C6, and GEOV2 is superior to GEOV1. RMSE and yearly mean LAI bias between one and another LAI product are vulnerable to topographic indices, especially to altitude. Q-statistic in Geodetector is smallest related to relief amplitude, biggest to vegetation for MODIS LAI product, and biggest to climate for Geoland2 LAI. Altitude, vegetation, and climate play a dominant role in spatial distribution of LAI. The validation experience demonstrates the importance of topography, vegetation and climate for LAI estimation over mountainous areas. Considerable attention will be paid to the production of higher quality LAI products in topographically complex terrain.
To explore the impact of wetland park on regional climatic comfort, numberical simulation sensitive experiments of wetland area and position have been conducted on wetland park planning in Liangping, Chongqing, using Weather Research and Forecasting Model (WRF). Based on local dominant wind direction and actual project requirements, sensitive experiments in the conditions of no wetland, and wetland area of 10 km2, 15 km2 and 20 km2 have been designed respectively. By comparing the mean 2 m temperature and 2 m moisture of different experiments, the wetland park with an area of 15 km2 and 20 km2 has a better cooling effect on the study region. And then, experiments with different spatial patterns of wetland, namely, by putting wetland in the southwest and northeast of protection area respectively, and also the experiment of dividing wetland into two parts, placed in SW and NE separately, have been tested. By calculating and comparing a 10 m wind field, 2 m temperature and 2 m universal thermal climate index, the results showed that the wetland park can bring a preferable local climate comfort when its area is around 15 km2 and it can be divided into two parts with a larger NE part, which may be the result of the generation of a new ventilation corridor. This also means that the status of local wind environment should be an important reference for wetland park planning.
Eco-environmental issues, such as climate change, ecological deficit and water shortage have been prominent in recent years. The influences of a large-scale tourism activity on ecological environment cause widespread concerns from researchers. As an important tool to assess the impact of tourism industry on environment, a series of research results of tourism ecological footprint, tourism carbon footprint and tourism water footprint derived from ecological footprint theory have emerged in recent years, which gradually composed tourism footprint family, and played an important role in assessing the influence of China's tourism industry on environment. This paper aims to grasp the latest research progress and trends of tourism footprint family in China. Based on research scales, research methods and research contents, it makes a summary of the improvements of tourism ecological footprint, tourism carbon footprint and tourism water footprint. The results indicate that analysis system of tourism carbon footprint at different scales has formed, analysis system of tourism ecological footprint is still in the process of perfection, analysis system of tourism water footprint is in the forming process; tourism carbon footprint generally used top-bottom method based on IOA and bottom-top method based on LCA, tourism ecological footprint and tourism water footprint mainly adopted bottom-top method based on LCA; analytical framework of tourism footprint family, including 7 components of tourism transportation, accommodations, catering, sightseeing, shopping, entertainment and waste disposal, is accepted by researchers, however it is not completely used in analysis process; ecological footprint, carbon footprint and water footprint measurement for tourism destinations and tourists are main research contents, and a series of suggestions to reduce tourism footprint are proposed. And then results of comparative analysis show that research scales, research methods, analytical frameworks and research contents are common to tourism ecological footprint, tourism carbon footprint and tourism water footprint, but measurement standard and evaluation function are individual; tourism footprint research is a fresh perspective with comparative advantage in quantitative measurement, research scale, regional comparative analysis, and specific policy compared to traditional research methods. In addition, we find that the insufficiency of tourism footprint approach includes measurement accuracy, evaluation comprehensiveness, spatiotemporal analysis and theoretical innovation, and makes prospects for China's tourism footprint research combined with the trends of international tourism footprint research. We hope that this paper can provide some suggestions for China tourism footprint research and sustainable tourism development.
Food waste has become a global problem, which causes widespread concern from the public. The consumption segment is an important part of food waste, and it is increasingly serious. Food waste at the consumer segment is mainly divided into household food waste and food waste outside home. Food waste at the consumer segment has different impacts on national food security, resources and environment, and social and economic development. Food waste at the consumption segment is affected by factors such as economic and social development, cultural background, demographic characteristics, and consumer behavior and awareness. At present, the study of food waste at the consumer segment mostly uses methods such as weighing (or estimating) and measurement model. It still needs to be further explored by developing reasonable quantitative methods, establishing complete theoretical models and proposing concrete research methods. In addition, to reduce food waste at the consumer segment, we should encourage multi-stakeholders to make a joint effort to deal with food waste at the consumer segment from the perspectives of government, society, individuals and other angles.
