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Context Salt precipitation and its influence on evaporation have been widely studied in recent years. However, the evolution process of salt precipitation and evaporative flux is poorly understood under various evaporation demand (ED) rate condition, which is defined as the evaporation rate of distilled water from soil under constant radiation conditions. Aims and methods This study investigated the evolution of salt crust and evaporative flux on sand soil columns with fixed saline groundwater at a depth of 20 cm under four ED conditions (29.5, 21.5, 9.0 and 4.0 mm day−1). Key results Evaporation rate significantly decreased in all treatments because the salt crust was elevated and salt domes formed, but the salt patterns of salt precipitation and evaporation exhibited significant differences between different EDs. The homogeneous fine powder crystals precipitated under relatively high ED conditions (29.5 and 21.5 mm day−1), and tended to aggregate and form an elevated salt crust in the initial period of salt precipitation. Consequently, it resulted in a sharp decrease in evaporation during the initial period of salt precipitation. In contrast, discrete and large crystals observed under low ED conditions (9.0 and 4.0 mm day−1), resulted in a stable evaporation stage during the initial period of salt precipitation. The highest relative evaporation rate was observed under the lowest ED condition when the evaporation rate reached stability, which was attributed to the formation of small and discrete salt domes, indicating that both the upward and lateral growth of salt precipitation were influenced by ED. Conclusions and implications The physics of salt crust formation needs to be considered in understanding how salt precipitates on the soil surface.

The spatial distribution of groundwater exploitation potential is crucial to the sustainable management of groundwater resources in arid regions. In this study, an effective approach is developed using a geographical information system (GIS) associated with the Dempster-Shafer (D-S) theory to explore the groundwater exploitation potential based on eight factors (i.e., slope, topography, distance to a river, canal density, lithology, land use, soil type, and groundwater depth)based on pumping test data. Different groundwater exploitation potential zones from the output map are classified as follows: very high (0.67–0.96, 8% of the total area), high (0.45–0.67, 8%), moderate (0.27–0.45, 14%), low (0.13–0.27, 24%), and very low (0.02–0.13, 46%), in the Hotan River basin of the Kunlun Mountains, China. The groundwater exploitation potential is highest in a gravel plain in the piedmont and gradually decreases from the piedmont to the desert. The predicted spatial variability of groundwater exploitation potential can explain 71% of the measured pumping test data. The uncertainty of the groundwater exploitation potential map ranges from

Quantifying and separating the impacts of hydroclimatic change and human activities on streamflow consumption are crucial issues for the planning, management, and rational allocation of water resources in arid inland river basins. Generalized additive models were used to reveal the interactions between climate, land-use change, and streamflow consumption in the mainstream Tarim River basin in Northwest China. The results showed that streamflow has decreased, while streamflow consumption has had an increasing trend in the upper reaches and a decreasing trend in the middle and lower reaches during the past 45 years. Land-use change was estimated to contribute 50.1–84.30% (mean of 58.1%) of streamflow consumption, and it was followed by climatic change, which contributed 10.5–28.3% (mean of 21.5%), and inflow runoff, which contributed 11.8–23.6% (mean of 17.7%) from 1970–2015. Land-use change played a dominant role in streamflow consumption in the mainstream Tarim River basin. Cropland expansion and urban area growth were the primary factors causing the decreased streamflow and increased streamflow consumption in the upper reaches. The streamflow consumption in the middle and lower reaches decreased, which was attributed to the decreased inflow. The results are useful for informing policy-making accordingly so that the river can be properly restored, which will benefit the ecosystem services.

The tight sandstone reservoirs of the Benxi Formation are characterized by low pore and low permeability inhomogeneity, etc. It is important to conduct a comprehensive evaluation study on the characteristics and logging of the tight sandstone reservoirs of the Benxi Formation for exploration and development. The study focuses on the application of imaging logging data such as nuclear magnetic resonance (NMR) and array acoustic wave, combined with conventional logging, to carry out the characterization and comprehensive logging evaluation of coal-bearing tight sandstone reservoirs. The study shows that the rock types of tight sandstone of Benxi Formation include quartz sandstone and rock chip quartz sandstone; the porosity is mainly distributed in (1.5%~4.5%) and the permeability is mainly distributed in (0.01mD~0.3mD). The porosity was solved by NMR logging; the permeability was solved by SDR calculation model; the water content saturation was solved by Indonesian equation considering the influence of mud; and the mud content of logging curve was solved by CGR, all of which achieved good agreement with the results of assay analysis. Various methods were used to discriminate the gas content of the reservoir. The rock brittleness indices calculated using sonic imaging and lithology scanning logs are consistent with each other.

Soil organic matter plays a fundamental role in terrestrial ecosystems. However, little is known about the spectral characteristics and fluorescent components of soil dissolved organic matter (DOM) in peri-urban ecosystems and their influencing factors. In this study, we used the fluorescence excitation-emission matrix and parallel factor analysis (EEM-PARAFAC) to characterize soil DOM in a peri-urban Critical Zone Observatory watershed in Eastern China. Soil samples were collected at depths of 0–10 cm, 10–20 cm, and 20–40 cm from 82 sites (29 forest, 11 orchard, and 42 cropland). The results showed that soil organic carbon and water-soluble organic carbon content varied with land use type, and both were significantly higher in forest than cropland and orchard samples. Three fluorescent components, humic-, fulfic-, and protein-like substances, were derived from soil DOM using the PARAFAC model. All these components were distributed differently in the three land use types, as were their UV and fluorescence indices. The spatial distribution of soil DOM showed that the quantity and chemical composition of DOM were affected by environmental variables and human disturbance, among which pH and altitude significantly affected DOM content. Anthropogenic parameters such as distance to road and distance to town strongly influenced the chemical composition and characteristics of soil DOM. Negative correlations were observed between humic-like substances and distance to road or town, while positive correlations were observed between protein-like substances and these two parameters. These results demonstrate the pronounced influence of human activities on DOM composition and characteristics in the watershed area. The findings highlight the value of soil DOM characterization to better understand the origin, composition, and fate of DOM in soils in peri-urban critical zones.

Urbanization has significant effects to ecosystems in watersheds, but the link between surface water quality and the dissolved organic matter (DOM) composition is poorly understood. We investigated the fluorescent intensities (Fmax) of DOM components and examined their correlation with the water quality parameters in peri-urban (Zhangxi River) and urban (Lu River) watersheds in Ningbo, East China. DOM quality was measured by fluorescent excitation-emission matrices (EEMs) coupled with parallel factor analysis (PARAFAC). Terrestrial humic-like components (C1 and C2) and protein-like component (C3) were derived by the PARAFAC model. We found more serious water pollution (significantly higher values for most water quality parameters, i.e. chemical oxygen demand (COD), chlorophyll a (Chl-a), dissolved organic carbon (DOC), ammonia and total suspended solids (TSS)) in urban than peri-urban watersheds. However, there were no significant differences in the levels of total nitrogen (TN) and total phosphorus (TP) between the urban and peri-urban watersheds. The results showed that the urban watershed had higher terrestrial humic-like C1 (39%) and lower protein-like C3 (30%) than the peri-urban watershed, while the peri-urban watershed showed an inverse trend (33% and 37%, respectively). The results also revealed that the DOM fluorescent indices were significantly different between the peri-urban and the urban watersheds. Redundancy analysis (RDA) was applied to evaluate the correlation between DOM fluorescent indices and water quality parameters (i.e., COD, TN, TP, DOC). It revealed that the pollution sources and water quality correlated to the fluorescent indices and the C1-C3 DOM fluorescent components. A significant linear relationship between COD and C2 was found in both watersheds, suggesting that C2 might be a good COD indicator. Our results suggest that the distinctive DOM composition between the watersheds could be attributed to different human activities at both sites. The correlation between DOM fluorescent components and water quality can be assessed by the EEM-PARAFAC method, indicating considerable potential for the use of this technique to monitor surface water quality.

The effects of salt precipitation on water and heat transport in soil have garnered considerable attention. However, salt precipitation growth on the soil surface and its influence on soil evaporation and temperature under a fixed groundwater table are not well understood. Therefore, the objective of this study was to investigate the impact of the evolution of salt precipitation on evaporation and temperature in sandy soils with a fixed groundwater table depth (20 cm). The laboratory experiment consisted of two treatments for sand columns: one with fresh groundwater, and the other with saline groundwater. Regions with salt precipitates expanded laterally and vertically whereby a salt crust was formed that disconnected from the soil. The lateral growth of salt precipitation had a minor impact on evaporation as the soil remained wet, while mostly being covered by the salt crust. However, the elevated salt crust caused a sharp decrease (>60%) in the evaporation rate. Therefore, a new stage of saline soil evaporation was determined; the evaporation rate was further reduced by the elevated salt crust. Moreover, the soil profile temperature decreased when the soil was covered by the salt crust, which is likely attributable to the increased albedo and the formation of a layer of air owing to the elevated salt crust. Therefore, we suggest that the upward growth of salt precipitation should be comprehensively studied because it can cause significant reductions in evaporation rates and soil temperature.

Abundant data sets produced from long-term series of high-resolution remote sensing data have made it possible to explore urban issues across different spatiotemporal scales. Based on a 40-year impervious area data set released by Tsinghua University, a method was developed to map the speed and acceleration of urban built-up areas. With the mapping results of the two indices, we characterised the spatiotemporal dynamics of built-up area expansion and captured different types of expansion. Combined with socioeconomic data, we examined the temporal changes and spatial heterogeneity of driving forces with an ordinary least square (OLS) model and a panel data model, as well as exploring the environmental effects of the expansion. Our results reveal that China has experienced drastic urban expansion over the last four decades. Among all cities, megacities and large cities in eastern China, as well as megacities in central and northeast China have experienced the most dramatic urban expansion. A growing number of cities are categorised as thriving, which means that they have both high expansion speed and acceleration. The overall driving force of urban expansion has significantly increased. More specifically, it was associated with population increase in the early stages; however, since 2000, it has been substantially associated with increases in GDP and fixed asset investments. The major driving factors also differ between regions and urban sizes. Urban expansion is identified as being closely associated with environmental deterioration; thus, speed and acceleration should be included as key indicators in exploring the environmental effects of urban expansion. In summary, the results of the presented case study, based on a data set of China, indicate that speed and acceleration are useful in analysing the driving forces of urban expansion and its environmental effects, and may generate more interest in related research.

In the process of compact city development, the limited availability of the land resources for green space (GS) would represent a major challenge for urban environments. In this paper, the long-term compact urbanization process of an island city (Xiamen, China) was selected as an example to analyze the historical spatial patterns of GS within the built environment. This study focused on urban GS at a neighborhood scale to analyze GS on a fine scale. Urban GS was extracted using the normalized difference vegetation index based on GF-1 remote sensing images. The results revealed several trends: (1) Newer built-up areas had a larger proportion of GS, more diversified GS types, and larger per-capita GS area. (2) The proportion of GS within various urban functional land use types presented great differences, both at the class level (age of the built-up area) and at the landscape level (the entire built-up area). (3) Significant differences in the proportion of GS and per-capita GS area were identified among various residential land types. The results from this study can contribute to the practical application of urban planning and policy-making.

Urban agglomeration (the spread of cities into large agglomerations) has become the main form of urbanization in China, and natural ecosystems surrounding the urban areas are becoming degraded and fragmented as a result. Although ecological indicators have been widely used to assess the regional ecological stress resulting from urbanization, few of them consider spatial adjacency relationships between urban and natural landscapes. From this perspective a novel ecological indicator, the Eco-Erosion Index (EEI), was developed and applied to assess the regional ecological stress caused by urban agglomeration development across 26 cities in the Yangtze River Delta, China (YRD). We analyzed: i) temporal change in land use and land cover (LULC) and ecosystem services value (ESV) in YRD from 1990 to 2010, ii) spatiotemporal dynamics of EEI of YRD at different scales: provincial, municipal, and 5 km-grid, iii) inter-relationships between EEI and LULC and ESV to explore its effectiveness as an indicator. The results showed that urban agglomeration in YRD has led to increasing regional ecological stress from 1990 to 2010. EEI values increased from 0.197 in 1990 to 0.321 in 2010. The closer to Shanghai City, the greater the EEI values of the cities become. EEI is highly related with LULC and ESV but integrates these two variables as it represents both the spatial occupation and landscape adjacency effects. The EEI values demonstrate some scale effects, and EEI at fine scale provides useful information to guide sustainable urban landscape management.

Soil water holding capacity is an important soil property which influences soil and water conservation as well as land degradation and development. Some studies indicated that field capacity (FC) was increased as soil organic matter (SOM) is improved, but the positive effect of SOM on FC was still contradictory. No consistent reports were found for the SOM potential that could be increased. Whether FC could be improved due to increase in SOM by organic amendment is not well established. It is still unknown whether or not there is benefit of improving SOM for enhancing FC; what is the threshold level of SOM for increasing FC, and how much SOM can be boosted. The field study and literature review were conducted to answer all those questions. Soil samples were taken at four sties manured and not manured in the Southern United States, then SOM and FC were measured. The soils amended with poultry litter had higher SOM (3.2%) and FC (35.38%), while the soils without amendment of poultry litter had lower SOM (1.7%) and FC (30.33%), a positive effect of SOM on FC was observed. For different soils with various clay content, a strong positive relationship was observed for soils with clay content less than 15% (R2= 0.7). We found that FC started increasing as SOM was increased over 2%, it is the threshold level of SOM for improving FC. Previous research also reported that there was no positive effect on FC for cultivated soils with a mean SOM of 1.2% in Greece. Another study found that the increase in water content is significant for sandy soils with 0 to 20% clay content. Our results revealed a pronounced effect for silt loam soils with 1 to 28% clay as SOM was larger than 2%. The SOM ranged from 0.9 to 5.42 %, with a mean value of 2.60 % for the 167 soil samples we measured. We found the highest level of SOM that amendment of poultry litter can increase was not greater than 6.0 %. We suggest SOM should be increased over 2% for improving FC, there is large room for SOM improvement in subtropical humid regions.

The interaction between climate change trends and water cycle variables is complex. The spatial distributions and trends of hydroclimatic variables (precipitation, temperature, water vapor pressure, and relative humidity) at 65 stations in Xinjiang in 1961–2011 were analyzed. Five meteorological stations were selected for a detailed analysis of the changes in climatic factors. We explored the relationship between water vapor pressure, relative humidity, temperature, and precipitation using nonparametric methods [the block bootstrap (B-B) method, Mann-Kendall (MK) test, and a generalized additive model (GAM)] for data from 1940 to 2011. The results showed that temperature, precipitation, and water vapor pressure at most stations increased over the period studied, while relative humidity decreased in the north of Xinjiang, and increased in the south. The results indicated that the temperature and water vapor pressure were elevated. At the same time, there was a large spatiotemporal heterogeneity of precipitation and relative humidity among the five stations. The water vapor pressure had a significant positive relationship with temperature and relative humidity, but the temperature trend with relative humidity displayed a negative relationship. The relationship of the precipitation and temperature trends with water vapor and relative humidity was either positive or negative. The most significant controlling factor for the climate variables was relative humidity, which was governed by water vapor pressure in the study area. Further investigations are needed to better understand the climatic influences in other complex physiographic landscapes, and to determine reliable mechanisms to more effectively integrate water cycle variables, high resolution data, and climatic modeling.

Hexabromocyclododecanes (HBCDs) are a class of widely used brominated flame retardants (BFRs) that exhibit strong hydrophobicity. The ubiquity and persistence of HBCDs in sediment have attracted significant attention because of public health concerns. The environmental fate and ecological risks of HBCDs closely depend on their phase distribution in sediments. However, little information is available regarding the freely dissolved concentrations (Cfree) of HBCDs in sediment porewater. In this study, we developed a method to measure Cfree of HBCDs in sediment porewater using triolein-embedded cellulose acetate membranes (TECAM). The TECAM-to-water partitioning coefficient (log KTECAM) was 4.69, 4.77, and 4.63 for α-HBCD, β-HBCD, and γ-HBCD, respectively. In sediments, HBCDs sorbed to the sediment solid phase accounted for more than 99% of the total chemical mass. The dissolved organic carbon (DOC)-water partition coefficient (KDOC) values were derived from TECAM measurements, and the log KDOC values ranged from 5.77 to 6.23 for the three HBCD diastereomers, suggesting a strong tendency for HBCDs to sorb to DOC. The high sorption of HBDCs for DOC implies a potential for DOC-facilitated transport which may enhance the environmental mobility of HBCDs.

Cities have become a major source of greenhouse gas (GHG) emissions and controlling urban GHG emissions is a critical response to global climate change. Many previous studies on urban GHG emissions focused on inventories, changes and impact factors but few investigated the distribution of spatial sources within a city. Although inventories of a city can give information of GHG emissions from different sectors, urban government and planners need to know where emissions occur and how (or why) they occur where they do. It is thus important to spatially apportion GHG emission within a city for the practical application of GHG emission management and policies. In this study, we develop a framework for the spatial apportionment of urban GHG emissions. Xiamen is taken as a typical rapidly urbanizing city in China to demonstrate the framework of spatial apportionment. Results show that the ranking of GHG emission intensity for different land-use types of the city is manufacturing, mining, warehouse land, service industry land, transportation land, residential land and agriculture land with a ratio of 89:54:23:14:1. The vast majority of land for GHG sequestration was located in the peripheral area of the city and most land-use types in the central region of Xiamen had high GHG emissions. The implication for low-carbon urban planning is then discussed in terms of structure and connection strategies. Integrated with socioeconomic factors and urban land-use distribution, the spatial apportionment of GHG emission inventory can provide a more accurate analysis of emission sources and better management of emission sources through urban planning.

Carbon dioxide (CO2) emissions from urban office buildings energy usages (BEC) constitute a substantial component of anthropogenic greenhouse gas emission, and are set to rapidly increase with further urbanization. Establishing a concise, accurate, and realistic model that can predict future emissions is challenging but essential for strategies to develop low carbon construction and sustainable development in urban areas. In this paper, the operational energy use for 294 office buildings across China was collected and analyzed. We focus on four main variables, and analyze a further ten second-level variables, to elucidate the role that a building’s occupants, its structural characteristics, and localized natural conditions play in determining energy consumption. Using general regression neural network (GRNN), the factors’ direct and indirect effects on energy consumption were tested. A building’s structural attributes had the most impact on energy-related CO2 emissions, followed by the relevant socioeconomic conditions, the micro-climate, and finally the regional climate. A version of the model that was constructed with interaction between the four main variables was found to be the most precise. GRNN combined with urban development scenarios was used for the prediction of cities’ future CO2 emissions. Economic development and improving standards in the construction industry could have significant impacts on future CO2 emissions. This study provides a detailed method that could be used to explore the dynamics of office energy use and competing options for the construction of low-carbon office buildings.

Organophosphate esters (OPEs) pose increasing concerns for their widespread distribution in soil environments and potential threat to human health. In this study, we investigated the occurrence and associated risks of seven OPEs in surface soils and the potential influence of human activities on soil OPE contamination in a heavily urbanized region of the Yangtze River Delta in Eastern China. All target OPEs were detected in the soil samples (100% of samples) reflecting their widespread distribution in the study region. The total OPE concentration (the sum of the seven OPEs) ranged from 162.7 to 986.0 ng/g on a dry weight basis, with a mean value of 469.3 ± 178.6 ng/g. Tris (2-butoxyethyl) phosphate was the main compound, accounting for 67-78% of the total OPE concentration. Ecological risk assessment showed that tris(2-chloroisopropyl) phosphate, tris(2,3-dichloropropyl) phosphate, tris(2-butoxyethyl) phosphate, and tris(2-ethylhexyl) phosphate posed a medium potential risk to terrestrial biota (0.1 risk quotient1). The human exposure estimation showed insignificant risks to local population. Redundancy analysis revealed that the individual and total OPE contaminations were positively correlated with human activity parameters. The total OPE concentrations were positively correlated to population density (R

Office buildings are now responsible for a large portion of the durable building stock's total energy consumption and play a key role in determining urban sustainability. Based on remote sensing and GIS data as well as statistical analysis methods, we found that building construction characteristics, socio-economic conditions, climate conditions, and microclimate contributed 32.27%, 18.37%, 13.84%, and 10.66%, respectively, to office building energy carbon emissions in China. Floor area, number of energy consumers, regional scientific investment, and heating degree days had positive relationships with office energy usages. Among these, the number of energy consumers had the greatest effect on OEC and heating degree day had the least effect. Technological progress may reduce energy demand, but the energy waste of office workers in buildings that adopt more energy-saving appliance, or admire for more comfortable temperature environment could offset these savings. Most of the taller buildings surveyed were constructed recently and equipped with energy-saving appliances, but these savings may have been offset by greater use of energy associated with higher income level, and greater support for energy spending from the government. These results provide baseline information for designing emission reductions programs and further studies.

Greenhouse gas emissions from buildings energy consumption increase disproportionate since the 21st century which would accelerate exhausting the fossil fuel supply and threatening the local climate. Using factor analysis, we study the contribution of four groups of influencing factors to office building energy consumption by integrating social economic, building, macro-climatic and micro-climate regulation factors. It showed that micro-climate controlling ability had the least contribution (with 9.64%) to the office building energy usages. Nevertheless, micro-climate regulation ability should not be ignored for its improvement process is relatively easier and the investment is lower when comparing with renovations on buildings, macro-climate or social-economic conditions. Using a geographical detector model, the effects of urban micro-climate regulation ability on office building energy consumption is further analyzed. The results showed that when integrated with green space and water body, the effect for carbon emission reduction was more obvious than using one of them alone. The green space had area threshold for office building energy usages carbon reduction but water body has not. If land area permitted, water body construction is more suitable than green space for reducing office building energy usage carbon emission. This study will provide urban low carbon building construction from the view of planning and layout of ecological land such as green-space and water space.

Ecological civilization is no longer only a conceptual innovation but also a key national governance strategy in China. The State Council released the worldwide first national strategy for the circular economy, and the circular economy became a national development strategy in China.

Soil salt crusts have been shown to have a strong influence on evaporation and water movement in soils, and this has attracted considerable attention. However, there is little information available on these processes during flooding. The objective of this study was to investigate the evaporation rate, variation in the groundwater table, and soil water content of salt-crusted soil flooded by five floodwater depths: 2 mm (Treatment A), 6 mm (Treatment B), 10 mm (Treatment C) 14 mm (Treatment D), and 18 mm (Treatment E). The experiments were carried out using repacked homogeneous silt loam soil columns in the laboratory. The experimental results showed that salt crust formation led to a low evaporation rate. The salt crust tended to form a dome, and some breakage occurred when the salt crust was dry. The broken crust increased the evaporation rate, indicating that the evaporation occurred below the crust. The soil moisture did not significantly change in the soil profile from 20 to 70 cm during the experimental period, which indicated that the existence of the evaporation front located in a layer very close to the surface. The evaporation rate rapidly increased when floodwater was added to the soils and returned to its previous low value after the salt crust reformed. However, before the salt crust reformed, there was a total water loss of 2.1, 4.3, 6.6, 10.1, and 13.8 mm for treatments A, B, C, D, and E, respectively, indicating that only a portion of the floodwater evaporated, another portion of the floodwater was discharged into the groundwater, causing the groundwater table to rise, although only by a small amount (6 mm). Therefore, the groundwater recharge caused by flooding should be considered. Otherwise, groundwater consumption may be overestimated.

Climate change has caused a series of social, economic and environmental consequences both at global and regional scales, especially for the urbanized coastal areas in China. Sea level rise and extreme weather threaten human and property safety, as well as sustainable development in China's densely populated coastal areas; all those factors bring new challenges to costal management. This paper takes a typical coastal city, Xiamen City as a case to study the residents' cognition of climate change, and based on questionnaire survey in coastal communities to explore the strategy development dealing with the climate change under integrated coastal management (ICM) framework. The social cognition survey includes three aspects: knowledge of the climate change, perception of the impact of climate change and response to the climate change. The results showed that the resident's knowledge on climate change and its risk was still at a relatively low level on average. Among effects of climate change, temperature rise can be easily identified by people, while sea level rise is less known by residents. Facing climate change, if residents have plans reactively, we think their attitudes are positive, i.e. evacuation is seen as negative. It is delight that 69.6% residents' attitude to adapt climate change is positive. 42.0% of residents prefer protective measures rather than adjustment measures when facing climate change. Furthermore, we explored the primary factors that influence residents' cognition and selection preference on adapting measures through logistic regression. Our study suggests that public cognition significantly affect public participation on climate change and the community-based planning and management on climate change is urgently in need in the rapidly developing urbanization coastal areas, which will play an important role in integrated coastal management.

Household carbon emissions from energy use are rapidly increasing in conjunction with growing urbanization; their reduction is critical for local urban climate improvement and the sustainable development of cities. Low-carbon behavior is proved as a key element determining residents’ lifestyle. Understanding how that behavior affects household energy use will be useful in promoting low-carbon households. In this study, Xiamen, a coastal city was divided into areas at high and low risk of flooding. We used the path analysis method—integrated with behavior and socioeconomic factors—to explore the mechanisms of low carbon behavior effects on household direct energy use and related carbon emissions. We found that socioeconomic conditions combined with low-carbon behavior had direct and indirect impacts on household carbon emissions. Low-carbon behavior in the high-risk area contributed most to reducing carbon emissions. Education level was the important factors in the low-risk area. Government-led policies encouraging low-carbon behavior were effective in reducing household carbon emissions in the high-risk area. However, in low-risk areas, education about a low-carbon lifestyle is an effective means for reducing carbon emissions.

Food supply and consumption are critical for sustaining urban system functions, and are key determinants of the quantity and pathways of nutrient flow in cities. Nutrient elements from urban food consumption are becoming major pollutant sources in urban environments. Therefore, understanding flow magnitude and pathways, the role of a growing population, and changing dietary structure and technology in future nutrient metabolism are essential to understand cities as ecosystems and urban environmental management. Taking the city of Xiamen, a rapid urbanizing area of Southeast China as a case study, we simulated urban metabolism of three major food-sourced nutrient elements (carbon, nitrogen, and phosphorus or CNP) over 1991–2010 and environmental emissions. Impacts of future population growth, dietary habit change, and waste treatment improvement on various environments were forecast by scenario analysis. A sensitivity analysis was conducted to test how different waste treatment technologies affect environmental emissions from food-sourced nutrients. Our results show that the food-sourced CNP had various metabolic fluxes through urban systems, with carbon mostly emitted into the air and nitrogen and phosphorus mostly discharged into landfills and water. Population growth and dietary structure change will accelerate increases of nutrient emissions to the environment, whereas enhancing current waste treatment technology can just alter emissions to different environments. Based on the results, we discuss how food-sourced nutrient metabolism can be better managed, to enhance connectivity between cities and their hinterlands and maintain environmental emissions within the carrying capacity of the cities. Keywords: Urban metabolism, Nutrient flows, Carbon, Nitrogen, Phosphorus, China

Due to rapid urbanization and increasing energy consumption, human society poses increasing pressure on the surrounding ecosystems that it depends on. As a result, evaluation of urban development should view cities as complex ecosystems including human and natural elements. This paper establishes a carbon balance index (CBI) for an urban ecosystem based on its socio-economic development and land use and land cover change in Xiamen, a rapidly urbanizing coastal city in southeast China. Dynamic changes in CBI can quantitatively indicate the sustainability of the urbanization process from a carbon cycling perspective. Results show that Xiamen's carbon balance condition experienced three stages: the period 1987–2002 where CBI decreased slightly, 1992–2002 where CBI moderately increased from 1.4 to 4.2, and 2003–2011 where CBI rapidly increased from 5.2 to 17.3. The carbon imbalance increased with the expansion of urban scale and urbanization. By stepwise multiple regression analysis, it was found that...

The Aksu region within the Tarim Basin is a major source of windblown dust in China due to the arid climate and vast areas under intensive irrigated crop production. Despite the importance of crop production to human subsistence and the local economy, little is known about the amount of soil eroded by wind from agricultural lands in the region. Passive aeolian sediment collectors were used to measure soil loss from an irrigated cotton (Gossypium spp.) field and red date (Ziziphus jujuba Mill.) orchard in the Aksu Oasis during high wind events in 2012 and 2013. Mass of sediment trapped by the collectors was best described as a power function of height above the surface in the cotton field and red date orchard. Soil loss from the cotton field ranged from 0 to 142 g m⁻², whereas soil loss from the red date orchard ranged from 0 to 71 g m⁻² for single- or multiple-day high wind events. Total soil loss from the cotton field and red date orchard, for the high wind events observed in this study, was 130 and 96 g m⁻², respectively, in 2012 and 305 and 165 g m⁻², respectively, in 2013. Soil loss was similar to that reported from agricultural lands in other regions of the world. Although soil loss is relatively small compared with the Gobi Desert in China, poor air quality in the Tarim Basin necessitates identifying crop and soil management practices for reducing windblown dust and conserving the soil resource.

Since there is an increasing demand for integrating landscape ecology and urban planning theories to study complex urban ecosystems and establish rational and ecological urban planning, we introduced a new concept-urban functional landscapes which can be reclassified based on detailed land use data to fulfill the various urban functions, such as residential, commercial, industrial, and infrastructure purposes. In this paper, urban functional landscapes were defined based on urban land use data produced from Pleiades images, and then landscape metrics and population density were combined to identify the urban functional zones along an urban–rural gradient. The features of urban functional landscape patterns and population density were also analyzed, and their relationship has been explored. The results showed that the pattern of urban functional landscapes and population density in the urban functional zones (Urban center, Urban peripheral area, Landscape barrier, Satellite city and Far-suburb) along the urban–rural gradient in Xiamen doesn't totally conform to the classical theories in spatial and social aspects. Urban functional landscapes is potential of acting as bridges between the landscape ecology and urban planning theories, providing scientific support for rational urban landscape planning and urban land use policy making.