Research On Carbon Emission Effect And Coupling Relationship Between Road Network And Land Use At Grid Scale

Land use carbon emissions,including carbon emissions from land use changes and carbon emissions caused by human activities carried by land,are the main source of carbon emissions and have been the focus of various related fields.The road network will not only promote the change of land use along the road,but also promote the integrated development of urban agglomerations.Analyze the spatio-temporal evolution characteristics and coupling relationship between road network and land use carbon emissions,can provide new enlightenment and reference for promoting the green,integrated and healthy development of urban agglomerations,and is also of great significance for achieving regional carbon neutrality goals and implementing sustainable development strategies.This paper takes the Yangtze River Delta urban agglomeration with developed road network and high urbanization level as the research area,and constructs a grid of 3km based on land use data,road network data,population,lighting,energy consumption and other social and economic data in 2014 and2020,use software such as Arc GIS to analyze the spatio-temporal evolution characteristics of land use and road network density,and explore the spatial correlation between them;Construct a carbon emission accounting model and a coupling coordination model to analyze the carbon emission effects of road network and land use and their coupling coordination relationship.Finally,According to the research results,policy recommendations are given for regional carbon emission management and land spatial planning.The main research contents and conclusions are as follows:(1)The spatio-temporal variation characteristics of land use and road network density.The land use types of the Yangtze River Delta are mainly cultivated land and forest land,followed by water area and construction land,grassland and unused land are negligible.From 2014 to 2020,the area of construction land in the Yangtze River Delta has increased,while the area of other land types has decreased to varying degrees.About 4.5% of the land has changed types,mainly forest land and water areas have been converted to cultivated land,and non-construction land has been converted to construction land.The density of the road network in the Yangtze River Delta has increased significantly,and the density core has continued to expand spatially,the density belt has expanded and extended on a large scale,and a large number of new density cores have emerged.The land use structure and land transfer characteristics of different road network density areas are obviously different.The low-density area is dominated by cultivated land and forest land,mainly due to the transformation of forest land and water area into cultivated land and construction land,while the high-density area is dominated by construction land,mainly due to the transformation of cultivated land into construction land.The overall dynamic degree of land use showed a trend of rising first and then falling with the increase of road network density.(2)The spatial correlation between road network density and land use.Among the spatial correlation between various land use types and road network density: the spatial correlation between road network density and cultivated land,road network and water area is weak;Road network density and forest land showed a significant negative correlation,the degree of negative correlation increased,and Moran’s I index dropped from-0.2468 to-0.2968;The road network density has a significant positive correlation with the construction land,and the degree of positive correlation has increased.The Moran’s I index has increased from 0.5800 to 0.6391.The road network density has a significant spatial positive correlation with the land use degree,and the global Moran’s I index increased from 0.4375 to 0.5041 There is a positive spatial correlation between the increase in road network density and the overall dynamic degree of land use.Its high-high aggregation areas are irregular clusters and bag-like aggregations,which are mainly the extension of developed urban areas or relatively developed urban areas.The high-low aggregation area presents band-like aggregation with dot-like sporadic distribution,mostly in highways,trunk roads,and townships near nature reserves or scenic spots.Low-high agglomeration is mostly in coastal areas along lakes and rivers,which is the embodiment of reclamation projects in Yancheng,Nantong and other places,as well as river and lake development or conversion of farmland.The average land use dynamic degree is even higher than that of high-high agglomeration.Low-low aggregation is mainly in the mountainous forest areas in the south and the contiguous areas of cultivated land in the north,as well as scattered rivers,lakes,nature reserves,and adjacent towns and other areas,where they are less disturbed by road network expansion and the ecological environment is relatively stable.(3)Carbon emission accounting of land use and analysis of spatio-temporal variation characteristics.Carbon emissions in the Yangtze River Delta are far greater than carbon absorption.The main source of carbon emissions is energy consumption.In terms of space,carbon sources are mainly concentrated in urban areas along lakes and rivers,such as Hefei,Wuxi,Changzhou,Nanjing,Shanghai,etc.showing a trend that carbon source areas occupy carbon sink areas,and carbon emissions are gradually dispersed.The areas with high per capita carbon emissions are shrinking rapidly,and the areas with median values have small changes in area but obvious spatial migration.The area of low value area expanded significantly,and the area of negative value area shrunk.Low-value holes appeared in Shanghai,with per capita carbon emissions as low as 0.60 tons per person.The carbon emissions show obvious spatial differences in road network density areas.The land-average carbon emissions are significantly positively correlated with the road network density,and there is an inverted U-shaped relationship between per capita carbon emissions and road network density.In the time dimension,the average carbon emission in the low-density area increases and the high-density area decreases.(4)Analysis of the coupling degree and coupling coordination degree characteristics of road network and land use carbon emissions in the Yangtze River Delta based on the coupling coordination model.The high-value areas of the coupling degree are mainly distributed in Hefei,Nanjing,Changzhou,Shanghai.Low-value areas are mainly distributed in lakes and reservoirs,mountains and hills,various nature reserves and scenic spots.The overall coupling level of the Yangtze River Delta is on the rise,and the area of high-value areas continues to increase,showing a development trend of expanding to the surrounding areas centered on major urban areas.Compared with the degree of coupling,the area of highvalue areas of coupling coordination degree is obviously less,only distributed in a few areas such as Huangpu District,Putuo District,Xuhui District,Changning District in Shanghai,Liangxi District in Wuxi,Gongshu District in Hangzhou and Haishu District in Ningbo.The overall level of coupling coordination is also on the rise,but it is mainly due to the increase of low and moderate coordination areas,while the coupling coordination levels in highly coordinated regions rise slowly.