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Urban agglomerations have become a new geographical unit in China, breaking the administrative fortresses between cities, which means that the population and economic activities between cities will become more intensive in the future. Constructing and optimizing the ecological security pattern of urban agglomerations is important for promoting harmonious social-economic development and ecological protection. Using the Harbin-Changchun urban agglomeration as a case study, we have identified ecological sources based on the evaluation of ecosystem functions. Based on the resistance surface modified by nighttime light (NTL) data, the potential ecological corridors were identified using the least-cost path method, and key ecological corridors were extracted using the gravity model. By combining 15 ecological sources, 119 corridors, 3 buffer zones, and 77 ecological nodes, the ecological security pattern (ESP) was constructed. The main land-use types composed of ecological sources and corridors are forest land, cultivated land, grassland, and water areas. Some ecological sources are occupied by construction, while unused land has the potential for ecological development. The ecological corridors in the central region are distributed circularly and extend to southeast side in the form of tree branches with the Songhua River as the central axis. Finally, this study proposes an optimizing pattern with "four belts, four zones, one axis, nine corridors, ten clusters and multi-centers" to provide decision makers with spatial strategies with respect to the conflicts between urban development and ecological protection during rapid urbanization.

Traditional villages are important carriers of cultural heritage, and the quantitative study of their spatial characteristics is an important approach to their preservation. However, the rapid extraction, statistics, and estimation of the rich spatial characteristic indicators in these villages have become bottlenecks in traditional village research. This paper employs UAV (unmanned aerial vehicle) and handheld laser scanners to acquire three-dimensional point cloud data and construct a spatial feature three-dimensional calculation workflow of "field data collection—data processing—data analysis and application", which enables the rapid acquisition, processing, and analysis of three-dimensional village data. Typical case studies are conducted in Liukeng Village, China, focusing on the quantification of village spatial characteristics at three levels: topography, streets and alleys, and individual buildings, as well as comparative studies of multiple villages across different regions. The quantification of three-dimensional data reveals the regularity of village spatial characteristics and uncovers the spatial wisdom embedded in the site selection and spatial structure of traditional villages. This paper establishes a complete technical route for the quantitative analysis of villages, deepens public understanding of the diverse value of traditional villages, and provides technical support for research and practice in related fields. [ABSTRACT FROM AUTHOR]

Rapid urbanization leads to fragmentation of landscape and destruction of the ecological security network. A sound ecological security network promotes connectivity between ecological sources and mitigates the degradation of an ecological system. However, when identifying the ecological sources of the ecological network, studies available in the current literature did not simultaneously consider the structures, functions, and values of ecological patches. Our study aimed to fill this research gap, and our objective was to improve the framework for assessing the ecological security network. We demonstrated the application of the proposed framework through a case‐study of the urban agglomeration around Hangzhou Bay (UAHB), a rapid urbanization region in Eastern China. We improved the identification method of ecological sources by integrating the evaluations of ecosystem services value and ecological sensitivity, while we screened ecological sources by using the rank‐size rule and the natural breaks method. Based on the screened ecological sources, the ecological corridors were reconstructed and optimized for the UAHB region. The results from this study showed that ecological network has actually improved in the UAHB in the last 20 years. However, the structure and function of the ecological security network were strongly influenced by human activities and urban sprawl. The ecological security network has deteriorated locally in eastern coastal areas of UAHB during the past 20 years with strong spatial variability in ecological security patterns. To maintain an environment with well‐protected ecological quality, we proposed a set of five measures to improve the sustainable development of the ecological system. [ABSTRACT FROM AUTHOR]

In the traditional construction of ecological security pattern, the minimum cost path is extracted as the ecological corridor based on the minimum cumulative resistance model, and the ecological nodes are identified manually. This method lacks the consideration of the exchange process of energy flow and information flow in the ecological process, resulting in a certain lack of ecological security pattern in structure and function. Therefore, an ecological security pattern construction method integrating CVOR-GWLR-Circuit model is proposed to solve the above problems by transforming natural background data into localized correction variables and adding them to the ecological security pattern evaluation model. Taking Yunnan Province as an example, firstly, the ecological security evaluation system of "Contribution, Vigor, Organization, Resilience" (CVOR) is constructed based on the importance of ecosystem services and ecosystem health, and the ecological security of Yunnan Province in 2020 is evaluated, and the ecological source areas are identified combined with nature reserves. Then, the ecological resistance surface was constructed by considering land use data and topographic factors, and the landslide sensitivity evaluation model was constructed based on geographically weighted logistic regression model (GWLR) to correct the basic resistance surface. Finally, the circuit theory model is used to extract the ecological corridor and construct the ecological security pattern in Yunnan Province. The ecological pinch points and barriers in the ecological corridor are diagnosed by the current density, so as to identify the width of the ecological corridor and identify the key areas of ecological protection and restoration. The results showed that the ecological sources area of Yunnan Province was about 69,417.78 km 2 , accounting for 17.6% of the total area of the study area, mainly distributed in Dehong Prefecture, southwest Yunnan, Diqing Prefecture and Nujiang Prefecture in northwest Yunnan. A total of 780 ecological corridors were generated between the ecological sources, with a total length of about 197,598.2 km, an average length of 253.3 km, and the longest path length of 932.1 km. The ecological corridors are "spider web", linking southwest, northwest, northeast, central and southeast Yunnan Province. 36 ecological pinch points and 42 ecological barriers were identified. The research results verify that the ecological security pattern constructed by integrated CVOR-GWLR-Circuit model is more reasonable, which can provide scientific basis for regional ecological protection planning and ecological corridors design., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The increase in tropospheric ozone (O3) concentration has become one of the factors restricting urban development. This paper selected the important economic cooperation areas in Northeast China as the research object and collected the hourly monitoring data of pollutants and meteorological data in 11 cities from 1 January 2015 to 31 December 2019. The temporal and spatial variation trend of O3 concentration and the effects of meteorological factors and other pollutants, including CO (carbon monoxide), SO2 (sulfur dioxide), NO2 (nitrogen dioxide), and PM2.5 and PM10 (PM particles with aerodynamic diameters less than 2.5 μm and 10 μm) on ozone concentration were analyzed. At the same time, the variation period of O3 concentration was further analyzed by Morlet wavelet analysis. The results showed that the O3 pollution in the study area had a significant spatial correlation. The spatial distribution showed that the O3 concentration was relatively high in the south and low in the northeast. Seasonally, the O3 concentration was the highest in spring, followed by summer, and the lowest in winter. The diurnal variation of O3 concentration presented a "single peak" pattern. O3 concentration had a significant positive correlation with temperature, sunshine duration, and wind speed and a significant anticorrelation with CO, NO2, SO2, and PM2.5 concentration. Under the time scale of a = 9, 23, O3 had significant periodic fluctuation, which was similar to those of wind speed and temperature. [ABSTRACT FROM AUTHOR]