Carbon emission reduction potential assessment in food transportation by urban agriculture: A case study of main urban area of Nanjing, China.

As an emerging urban green infrastructure and continuous productive urban landscape, urban agriculture can increase the resilience of urban food systems and reduce carbon emission in food transportation. However, there are few studies in China on the potential of urban agriculture and its role in carbon emission reduction. With semantic segmentation and spatial analysis method to identify urban agricultural potential spaces on the ground and rooftops based on satellite images and Lidar point cloud data in the main urban area of Nanjing, we estimated their potential in vegetable production and the CO2 emission reduction effect in food transportation. The results showed that there were 2904.39 hm2 of ground and 2976.96 hm2 of rooftops in the study area with the potential to be used for urban agriculture. Under a scenario with 80% potential space utilization, it could produce approximately 225000 t of vegetables per year, which equated to 43.6% of annual vegetable consumption in the study area. Meanwhile, it would reduce CO2 emission in long distance food transportation by 63700 t per year.

Temporal and spatial patterns of habitat of Nipponia nippon in China under the background of climate change.

Crested ibis (Nipponia nippon) is one of the endangered species in the International Union for Conservation of Nature. It is of great significance to pay attention to the changes of its suitable habitat in the context of climate change. Based on the geographical distribution data of crested ibis, the MaxEnt model was used to predict the suitable habitat of crested ibis under current scenario and future climate change. The results showed that the prediction accuracy of MaxEnt model was high, with an AUC value of 0.989. The minimum temperature of the coldest month, the mean temperature of the coldest quarter, and the mean annual rainfall were the dominant environmental factors affecting the habitat of crested ibis. Under current climate scenario, the area of moderately and highly suitable area of Chinese crested ibis was 10.65×104 km2, mainly distributed in Shaanxi, Sichuan, Hubei, Henan, and Gansu. In the future, the suitable habitat area of crested ibis would increase significantly under climate change, mainly distributed in Anhui, Chongqing, Guizhou, Jiangsu, Hunan, Shandong, Shaanxi, Jiangxi, Taiwan, Yunnan, Liaoning, and Fujian. In the SSP126 scenario from 2041 to 2060, the suitable habitat area of crested ibis would reach the maximum, being 139.53×104 km2 higher than that of the current climate scenario, accounting for 19.6% of the land area. This study could provide a basis for policy making on the conservation of crested ibis under global climate change.

Construction and optimization of ecological networks based on future scenario simulation in Qianshan City, Anhui Province.

The rapid urbanization adversely affects landscape pattern of mountainous cities. It is of great practical significance to explore the spatial and temporal evolution of ecological networks in mountainous areas to achieve regional ecological security. Taking Qianshan City in Anhui Province as an example, based on the land use data in 2012 and 2020, we simulated the land use situation in 2036 with PLUS model, and constructed the ecological networks in 2020 and 2036, respectively. We further analyzed its spatial and temporal evolution characteristics and explored the optimization path of ecological network. The results showed that the scale of various land use types in Qianshan City would change little from 2020 to 2036. The construction land would be centered on the built-up area, expanding in a point and block shape to the surrounding area. The ecological space would be continuously squeezed and encroached. The overall complexity and connectivity of ecological networks in Qianshan City would increase. The number and area of ecological source sites would increase, expanding spatially to the southwest and northeast. The overall density and number of ecological corridors would increase, with a lack of ecological corridor connections in the east-west direction, which need urgent improvement. The stability of ecological networks could be improved through three major measures, including protection and restoration of source sites, optimization and cultivation of corridors, and zoning control.

[Using the environmental justice approach to evaluate equitable allocation of urban parks: A case study of main urban area of Nanjing, China]. / çŽ¯å¢ƒæ­£ä¹‰è§†è§’ä¸‹å ¬å›­ç»¿åœ°ç©ºé—´é ç½®å ¬å¹³æ€§è¯„ä»·­­ä»¥å—京市主城区为例.

Urban parks have broad benefits in promoting public health of urban residents and advancing urban sustainable development. The equity of urban park spatial allocation has a great significance for maintaining environmental justice. However, the current researches on the equity of urban park spatial allocation still focus on the quantity and geographical equality but pay less attention on the equity of quality and accessibility of spatial allocation. Based on the approach of environmental justice, with the main urban area of Nanjing as an example, we comprehensively analyzed the equity pattern of urban park spatial allocation from the three dimensions (six parameters), including park accessibility, area and quality. Integrated analysis methods were adopted, including internet map service for accessibility analysis, subjective and objective comprehensive quality evaluation, spatial autocorrelation and non-parametric test. The results showed that the spatial allocation pattern of urban parks in the study area had obvious core-edge characteristics. There was a certain degree of inequity in park accessibility, area and quality, with a relatively significant pattern of environmental injustice. There were significant differences in the inequity of six parameters in the three dimensions, with the accessibility score and accessible park area showing the most prominent inequity. The minimum time required to reach the park and the quality of the nearest urban park took the second place in inequity. The quantity of high-quality urban park and minimum time required to reach the high-quality urban park showed relatively small difference. The average values of accessibility score, total area and quality of urban parks accessible to high-income communities were 3.7, 2.7, and 1.6 times that of low-income communities, respectively. The results indicated that high-income communities enjoyed better accessibility, larger area and higher quality in terms of urban parks. Middle-income communities enjoyed the most prominent advantage of green space, while most low-income communities were unable to reach a high-quality urban park within 30 min's walk. Our results could provide a decision-making basis and planning reference for the optimal configuration and rational planning of urban parks in China.

[Effects of a Green Roof on Stormwater Regulation and Cost-benefit Analysis].

Increasingly frequent urban waterlogging disasters, which are mainly caused by the increase in impervious surfaces due to rapid urbanization, have attracted public attention. Green roofs are conducive to increasing the urban pervious surface area to control sources of runoff, which has great significance for the ecological environment. This study uses the green roof of the administrative building of Jinling Primary School in Nanjing as the study area. 76 rainfall-runoff events collected over 17 months (2016-06-2017-10) were used to calculate the comprehensive runoff control ability and factors influencing the green roof in the context of the site scale. Based on life cycle assessment theory, the benefits of stormwater regulation over its 30-year life cycle were quantitatively evaluated. The results show that:① The average retention of the green roof was 62.7%, which could have a significant impact on runoff and peak flow, reducing the runoff time and delaying the flood peak. ② The green roof has a strong ability to retain runoff during small and medium rainfall; however, this ability becomes low when the retention capacity is saturated or not fully recovered, even in small rainfall-runoff events. ③ The main factors affecting the retention ability of the green roof are the total rainfall, rainfall intensity, and water content of the growth substrate soil. ④ The green roof has great economic benefits, with a construction cost of about 12.51 yuan·m-3 and a return on investment of 0.41. The results of this study can provide an important scientific basis and decision-making reference for the planning and construction of green roofs and the promotion of related policies.

[Assessment of the potential for urban facade greening in Xinjiekou District, Nanjing, China.] / 南京市新街口地区垂直绿化发展潜力评价.

Green facade is an important strategy to improve the urban eco-environment and reduce the negative effects of human activities in central districts of cities which are land-scarce and lack green spaces. We first summarized the limiting factors for the construction of green facades locally and internationally. Then, we used the Xinjiekou District of Nanjing City in China as a case study area, and selected the wind environment, solar environment, and physical build environment that might impact the potential development of green facades as key factors to quantitatively analyze singlely by geographic information systems (GIS) and computational fluid dynamics (CFD). Finally, the potential area to develop green facades was assessed through a multi-factor overlay analysis. The results showed that 17726 m2 of wall spaces in the Xinjiekou District had a high potential for facade greening, accounting for 30.8% of all exterior wall space under a height of 12 m and 17.3% of the entire study area. Sunlight was a key limiting factor in determining whether a green facade should be developed. Irrigation was identified as another important factor that might strongly affect the growth of vertical vegetation in urban environment. The spatial distribution of walls suitable for facade greening was uneven, with an "inner-high and south-high" spatial pattern. Our results would help to guide the design and development of green facades in Xinjiekou, and also provide a reference for planning and utilizing green wall space projects in other built and dense urban areas.

[A review on the urban green space cooling effect based on field measurement of air temperature]. / åŸºäºŽæ°”æ¸©å®žåœ°è°ƒæŸ¥çš„åŸŽå¸‚ç»¿åœ°é™æ¸©æ•ˆåº”ç ”ç©¶çŽ°çŠ¶ä¸Žæœªæ¥å±•æœ›.

With the development of urbanization, the effect of urban heat island has become increasingly evident. As an essential component of the urban natural landscapes, urban green space plays an important role in mitigating the effect of urban heat island. However, facing the rapid urbanization and changing environment, how to rationally plan and design the green space and realize its best cooling effect which can improve the urban environment and microclimate is still an urgent problem to be solved. So there is a strong need for mulitiscale researches on the cooling effect of urban green space. This paper systematically gave a review on the cooling effect of urban green space based on field measurement of air temperature, the main factors that influenced the cooling effect of green space were explored from three aspects including the area and shape characteristics of urban green space, the structure characteristics of vegetation and the external factors which affected the cooling effect, and the characteristics of the cooling effect of the green space were summarized from the aspect of time variation and distance decay. Then, the main problems and future research prospects of urban green space cooling effect were put forward.

[Scale effect of Nanjing urban green infrastructure network pattern and connectivity analysis.] / å—äº¬å¸‚ç»¿è‰²åŸºç¡€è®¾æ–½ç½‘ç»œæ ¼å±€ä¸Žè¿žé€šæ€§åˆ†æžçš„å°ºåº¦æ•ˆåº”.

Based on ArcGIS, Erdas, GuidosToolbox, Conefor and other software platforms, using morphological spatial pattern analysis (MSPA) and landscape connectivity analysis methods, this paper quantitatively analysed the scale effect, edge effect and distance effect of the Nanjing urban green infrastructure network pattern in 2013 by setting different pixel sizes (P) and edge widths in MSPA analysis, and setting different dispersal distance thresholds in landscape connectivity analysis. The results showed that the type of landscape acquired based on the MSPA had a clear scale effect and edge effect, and scale effects only slightly affected landscape types, whereas edge effects were more obvious. Different dispersal distances had a great impact on the landscape connectivity, 2 km or 2.5 km dispersal distance was a critical threshold for Nanjing. When selecting the pixel size 30 m of the input data and the edge wide 30 m used in the morphological model, we could get more detailed landscape information of Nanjing UGI network. Based on MSPA and landscape connectivity, analysis of the scale effect, edge effect, and distance effect on the landscape types of the urban green infrastructure (UGI) network was helpful for selecting the appropriate size, edge width, and dispersal distance when developing these networks, and for better understanding the spatial pattern of UGI networks and the effects of scale and distance on the ecology of a UGI network. This would facilitate a more scientifically valid set of design parameters for UGI network spatiotemporal pattern analysis. The results of this study provided an important reference for Nanjing UGI networks and a basis for the analysis of the spatial and temporal patterns of medium-scale UGI landscape networks in other regions.

[Land use change and its effects on ecosystem services value in Ji' nan City of Shandong Province, East China].

Based on the GIS software platform, referring to the China 'Terrestrial ecosystem services per unit area value', and by using transition matrix, Costanza evaluation formula, and sensitivity analysis, this paper studied the change characteristics of land use and ecosystem services value in Ji' nan City in 1989-2009. During the study period, the built-up area in the City increased by 99.65 km2, while agriculture land and green space reduced by 103.21 km2, 90.4% of which was taken by the built-up land. The total ecosystem services value decreased from 256.22 x 10(6) yento 214.16 x 10(6) yen, with a decrement of 42.06 x 10(6) yen, mainly due to the decrease in the areas of agriculture land and green space. For the sustainable development of the population, resources, and environment in Ji'nan City, future urban planning should pay more attention on the natural resources protection, reasonable planning of land use structure, and maintenance of ecosystem stability and balance.

[Suitability assessment of construction land in the central and southern parts of Hebei Province, China based on potential-limitation model].

The suitability assessment of regional construction land is one of the important prerequisites for the spatial arrangement in regional planning, and also, the important foundation for the reasonable utilization of regional land resources. With the support of GIS, and by using the regional comprehensive strength and spatial accessibility analysis and the eco-environmental sensitivity analysis, this paper quantitatively analyzed the development potential and its ecological limitation of the central and southern parts of Hebei Province. Besides, based on the cost-benefit analysis, the potential-limitation model was accordingly developed, and the three land suitability scenarios under different developmental concepts were captured through the interaction matrix. The results indicated that both the comprehensive strength and the development potential of the study area showed a primacy distribution pattern, and presented an obvious pole-axis spatial pattern. The areas with higher eco-environmental sensitivity were mainly distributed in the west regions, while those with lower eco-environmental sensitivity were in the east regions. Regional economic development concept had important effects on the regional ecological security pattern and urban growth. The newly developed principles and methods for the land suitability assessment in this paper could not only scientifically realize the spatial grid of regional development potential and capture the future land development trend and spatial distribution, but also provide scientific basis and effective ways for urban and regional planning to realize region 'smart growth' and 'smart conservation'.