Integrated assessment of the cool island intensity of green spaces in the mega city of Beijing

Green space has a cooling effect that can contribute to the mitigation of the urban heat island. This study presents an integrated assessment of the cooling effect of green space in Beijing using Landsat 5 Thematic Mapper data and multiple regression analysis. The results showed that the average land-surface temperature for green space was 304.94 K, which was 5.32 K lower than that for commercial and residential land. Through analysis of 98 green space sites, this study found that the normalized difference vegetation index difference between a green space site and the surrounding built-up areas, the green space size, and the green space shape affected the cool island intensity of green space (GCII). However, because of its significant multicollinearity with green space size, the green space shape was excluded in the subsequent multiple regression analysis. Furthermore, for green space sites with a size over 10 ha, size had a close relationship with the GCII variances. For green space sites with a size under 10 ha, the uncertainty in the relationship significantly increased.