| With the development of urbanization,the urban surface landscape structure changes with the change of the landscape.Due to the huge differences in the physical characteristics and thermal radiation characteristics of different landscape types,the surface temperature will change,leading to different urban thermal environmental effects.It not only has an important impact on the urban environment and the health of residents,but also directly or indirectly causes a series of natural disasters.Based on MODIS surface temperature data and land cover data,this paper analyzes the temporal and spatial changes of landscape and the evolution of surface thermal environment effects in the Beijing-Tianjin-Hebei region from 2000 to 2015,Then divide the study area into several types of grids,namely 1km×1km,5km×5km,10km×10km,15km×15km and 20km×20km,and construct ordinary least squares(OLS)and geographic weighted regression(GWR)Model to study the impact of potential scale effects on the quantitative relationship between landscape structure and surface temperature.The main research results obtained are as follows:(1)From 2000 to 2015,the landscape structure of the Beijing-Tianjin-Hebei region has undergone major changes,with obvious temporal and spatial differences.The Beijing-Tianjin-Hebei region has the largest proportion of woodland landscape and cultivated land landscape.The cultivated land landscape area has decreased significantly in 15 years,while the construction land landscape has shown a rapid growth trend during the research period,through the calculation and analysis of the transfer matrix,it shows that the development of urbanization and the increase of construction land mainly come from the conversion of cultivated land.(2)The topography of the Beijing-Tianjin-Hebei region is relatively complex,and the surface temperature distribution in this area in summer is significantly regional.The temperature in the southwest is relatively high,while the temperature in the north is relatively low,and as the latitude gradually increases,the temperature gradually decreases.On the whole,the surface temperature changes in the Beijing-Tianjin-Hebei region from 2000 to 2015 showed a rapid increase in the central area,a decline in the north,and an overall increase in the south.From 2000 to 2015,the surface thermal environment effect in the Beijing-Tianjin-Hebei region was gradually enhanced,with obvious spatial distribution changes.The surface thermal field in 2000 was mainly in the medium temperature and below temperature zones,and the high temperature zone was small in size and showed a pattern.The spatial pattern of thermal environment is relatively simple.By 2015,the high temperature and sub-high temperature areas in the Beijing-Tianjin-Hebei region have increased significantly,showing a radial distribution,and the thermal environment effect has been significantly enhanced.(3)From the spatial distribution pattern of surface temperature under different spatial unit changes,it can be seen that Moran's I value shows a downward trend in the1-20 km scale change.The analysis of spatial autocorrelation shows that the spatial distribution of surface temperature changes from discrete to concentrated in the 1-20 km scale change;The descriptive statistics of surface temperature show that the spatial distribution pattern and parameters of surface temperature have changed with the change of scale,and the average change has remained within the range of 0.13?,showing a downward trend.(4)The analysis of the correlation between the proportion of landscape types in the Beijing-Tianjin-Hebei region and the surface temperature shows that the woodland landscape has a very significant negative correlation with the surface temperature,which can effectively inhibit the surface thermal environment effect in the BeijingTianjin-Hebei region,while the construction land and the cultivated land landscape are related to the surface temperature.There is a very significant positive correlation between temperature,and these two landscape types have an important impact on the surface thermal environmental effects in the Beijing-Tianjin-Hebei region.The correlation between landscape types and surface temperature varies with scale changes.This shows that scale changes will have a certain impact on the correlation analysis between landscape types and surface temperature.Choosing an appropriate scale is of great significance in the analysis of the interaction between landscape structure and surface thermal environment..(5)The study of the multi-scale effects of the changes in land surface temperature and the changes of various landscape types from 2000 to 2015 further shows that the water landscape changes and the cultivated land landscape changes have a very significant negative correlation with the land surface temperature changes,and the correlation is the highest in the spatial unit of 10km×10km.The increase in water landscape inhibits the increase in surface temperature,and the cooling effect is obvious.The correlation between dynamic changes in landscape and changes in surface temperature varies with scale changes;The correlation between changes in construction land and farmland landscape and changes in surface temperature increases as the scale increases.On the 10km×10km spatial unit,the correlation between changes in grassland and water landscape and changes in surface temperature is the highest,indicating that scale changes have a certain impact on the correlation analysis between landscape changes and surface temperature changes.(6)Both OLS and GWR analysis have confirmed that the composition of construction land is an important factor leading to the following problems: UHI phenomenon in large urban agglomeration areas;For the OLS model,the model relationship between the surface temperature and its driving factors shows a significant spatial scale effect,which varies with different spatial analysis units;Compared with OLS,the GWR model can well explain the types of building land landscapes in different spatial units that affect the surface temperature,and can adapt to lower-scale spatial non-stationarity dependence that is stronger than the OLS model.This study emphasizes the significant spatial heterogeneity,which is related to the UHI effect in large-scale urban agglomeration areas,which indicates that the potential scale effect and uncertainty caused by the use of different spatial scales and methods should be considered when simulating the thermal effects of urbanization.consider.This will supplement the current urban thermal environment research,will help deepen the understanding of the landscape and inspire the planning of urban thermal environment supervision. |
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