| The rapid growth of the global urban population has promoted the development of urbanization.Urbanization-induced changes in the spatial configuration of land use/land cover(LULC)and landscape patterns have produced a series of negative impacts on the urban ecological environment,especially the increase in the surface urban heat island(SUHI)effect has seriously affected human health,climate change and ecological quality.At present,scholars at home and abroad have conducted extensive research on the impact of LULC changes on the SUHI effect and the response relationship between the two.However,from the perspective of temporal and spatial changes,the dynamic and quantitative analysis of the influence of the composition,configuration and pattern of LULCs in lakeside cities on the inland plateau on SUHI and the response relationship between them are still unclear.Based on remote sensing data,this paper explores the temporal,spatial and quantitative evolution characteristics of LULC and SUHI in the main urban area of Kunming city in recent 30 years by using Markov transfer matrix,dynamic attitude model,state index model,gravity shift model and exploratory spatial data analysis.On this basis,based on the analysis methods of urban-rural gradient,spatial statistics,landscape pattern index,etc.,the influence of Kunming LULC changes on SUHI effect was explored and the response relationship between them was revealed.The main conclusions are as follows:(1)In the past 30 years,the LULC structure in the main urban area has undergone active changes,and the overall performance is the growth of impervious surface,bare land and green space,and the decline of agricultural land and water bodies.The impervious surface increased by 304.59 km~2,and the overall migration was 3294.57 m in the direction of 47.92°to the southeast.The urban expansion transitioned from the mode around Cuihu Lake to the mode around Dianchi Lake.The number and density of patches continue to increase,and the overall landscape structure and shape become more and more complex.Except for impervious surface and bare land,the aggregation and connectivity of other land types decreased significantly,and there were different degrees of fragmentation.(2)In the past 30 years,the average LST of the main urban area has increased by1?,the SUHI area has increased by 218.5 km~2,and the intensity of the SUHI has gradually increased.The overall structure of the SUHI shows a decreasing trend in the low temperature area and high temperature area,and an increasing trend in the sub-high temperature area,the middle temperature area and the sub-low temperature area.SUHI centers show a distribution pattern ranging from scattered multi-centers,contiguous multi-centers to large-scale concentrated contiguous centers.The gravity center of each temperature zone shows different migration patterns,and the high temperature zone has migrated 3286.96 m in the direction of 29.75°to the north-east.The high and high gathering areas in the high temperature area gradually transitioned from the bare area dominated by dry land to the downtown area.(3)The changes in the composition and pattern of LULCs caused by the explosive growth of impervious surfaces in the context of rapid urbanization are the main reasons for the deterioration of SUHI.At the same time,the existence of a large area of bare surface is also an important reason for the aggravation of surface warming.In the past30 years,the average LST of all land types has shown an upward trend,but the temperature difference among all land types has gradually decreased.Agricultural land contributed the most to the regional temperature in the early stage of the study(1991-2000)and was gradually replaced by impervious surfaces in the later stage of the study(2009-2018).The total contribution value of agricultural land was only 0.601°C in the later stage of the study,while the total contribution value of impervious surface at this time reached 0.82°C.The impervious surface and the water body are the main heating and cooling types,respectively,but the warming effect of the impermeable surface is greater than the cooling effect of the water body.(4)The landscape pattern index well explained the impact of LULC landscape pattern changes on SUHI.As the number of landscape patches increased,the density increased,the shape became more complex,and the structure became diverse and uniform,SUHI was continuously strengthened.The urban-rural gradient analysis revealed the spatial correlation between the land cover index and LST.NDBI and NDBa I had the same change curve as LST along the urban-rural gradient,while MNDWI and NDVI showed the opposite trend.The relationship between the land cover index and LST in the main urban area is not a simple univariate linear relationship.NDBa I,NDBI and LST show a significant exponential relationship,while NDVI,MNDWI and LST show a significant quadratic polynomial relationship.The SUHI effect can be effectively reduced by rationally configuring the LULC structure,optimizing the landscape layout of the underlying surface,and rationally regulating anthropogenic heat emissions. |
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