Comparable Analysis Of Spatiotemporal Patterns Of Urban Land Cover Change Between Fuzhou And Taipei

Urban expansion is an important manifestation of social and economic development.With the deepening of urbanization,cities have begun to pursue high-quality development and create a high-quality living environment after rapid development.In the new round of general planning of land and space in Fujian region,Fuzhou City takes the "Cross-Strait Exchange and Cooperation Center" as one of the city’s properties,and plans to fully build a modern international city with riverside and seaside by 2050.The in-depth promotion of "the Belt and Road" initiative has further deepened the connection with Taiwan.Urban construction in Taiwan has taken the lead in entering the post-urbanization stage.Fujian and Taiwan have many similarities in the natural environment conditions.The comparative analysis of the expansion of cities in the two places with similar topographic conditions is of reference significance for the cities in Fujian,which are developing later.In the urban studies of Fujian and Taiwan,the land use cover data is used as the basic data for analysis,and the urban development process is revealed by monitoring the conversion between construction land and other land types.However,the spatial changes cannot accurately reflect the changes in the urban environment.Under the background that cities require high-quality development,it is necessary to dynamically analyze changes in the urban internal environmental structure to comprehensively reveal the laws of urban development and provide data and theoretical support for subsequent urban construction and management.In this paper,the urban area of Fuzhou and the Taipei metropolitan area(including Taoyuan City)are used as the research areas,and the Landsat series images are used as the basic data to extract the urban impervious surface and green space fraction information every 10 years from 1980 to 2020.The results of the impervious surface fraction were experimented by the threshold test method to extract the boundaries of the built-up area.Then,through the comparative analysis of the changes of urban expansion in time,space,pattern and shape to reveal the development processes and regularities of the two cities.And based on the method of statistical analysis,it analyzes the urban expansion of the two cities along the river,and explores the temporal and spatial development characteristics and regularities of typical cities in the two places in the past 40 years,in order to reveal the differences in the development regularities between the two cities.The results show that:(1)In terms of time-series changes,the built-up areas in the Fuzhou city generally showed an incremental,high-speed and high-intensity expansion.Both the impervious surface and green space continued to expand,and the proportion of impervious surface decreases while the green space increases.On the other hand,the built-up area of the Taipei city generally exhibited an incremental,low-speed and low-intensity expansion.The changes in surface coverage in the urban area were generally characterized by a decrease in the proportion of impervious surfaces and an increase in the proportion of green space.Totally,the built-up areas in both places continued to expand,and the proportion of internal impervious surfaces and green spaces was gradually optimized,but the urban expansion of the Fuzhou city was larger and faster.(2)In terms of spatial changes,the built-up area of the Fuzhou city mainly expanded to the lower reaches of the river and the coastal areas in southeastern and eastern.The growth peaks of the built-up areas and impervious surfaces moved outward gradually,and the growth peak of the green space area was contrary.The development of the built-up area in the Taipei city developed in the western and southwestern.The built-up area and the impervious surface expansion were tightened in the buffer area of different distances gradually.The urban areas of the two cities both extended to areas outside the basin,while the Fuzhou city mainly extended eastward with a larger change,while the Taipei city extended westward with a smaller amplitude.(3)Among the changes in the expansion patterns and boundary shape,the urban expansion of Fuzhou city was mainly extensional,showing a massive development,and the spatial form was developing towards compactness;the urban expansion of Taipei city also was mainly extensional,and in the later stage,the expansion of the enclave type and the filling type increased significantly,but the scale of the expansion was small and relatively fragmented and scattered,and the shape changes was small,and the form developed towards compactness.The urban form of the two places was developing towards compactness.The changes in Fuzhou city were more apparent and the magnitude were larger,while the changes were stable in Taipei city,relatively.(4)The bridges played an important role in promoting urban expansion in promoting urban expansion.The spatiotemporal distribution of urban bridges in Fuzhou was characterized by gradually advancing from the city center to the upper and lower reaches,and the passage of bridges further improved the accessibility of the road network.The number of cross-river bridges in the two places had gradually increased.The original number of cross-river bridges in Fuzhou was relatively small.With the construction of a large number of cross-river bridges,the urban built-up area had rapidly expanded along the river and gradually extended from the river bank to the hinterland of the land.In the base year of the study,the bridges across the river in Taipei were more densely distributed,but the bridges were still added in the way of inserting encryption to strengthen the connection between the city center and the peripheral areas.And the bridge had hardly impact on the expansion of built-up areas along the river.