How can urban blue-green space be planned for climate adaption in high-latitude cities? A seasonal perspective

Abstract

Climate change has increased the frequency of extreme climatic events and the intensity of heatwaves in high-latitude cities that have rarely been affected in the past, yet there is less attention to these regions. Therefore, we selected Copenhagen as the case, we used spatial/statistical methods to assess the cooling-effect of blue-green spaces in different seasons. We found (1) land surface temperature (LST) is negatively correlated with Normalized Difference Vegetation Index (NDVI) and Modified Normalized Difference Water Index (MNDWI) in all seasons; (2) Tree-covered greenspace with a compact shape would be a priority for climate adaption in high-latitude cities. While when the area of blue-green space is large to a certain extent (>1 ha), the complex shape also has a strong cooling-effect. Further, the area and cooling extent and intensity conform a logarithm function with significant correlations except for winter. (3) Compared with other seasons, blue-green space provides a higher cooling-effect in summer, and the mean cooling extent and intensity are 150 m and 2.47℃; (4) Background temperature can significantly affect the threshold value of efficiency (TVoE). The results of this study expand the understanding of the cooling-effect of blue-green spaces and provide implications for sustainable urban planning.