Abstract: The land surface temperature in the Tongzhou District, Beijing’s sub-center, was retrieved by a singlechannel algorithm. Seven cooling indicators, from the aspects of local environmental temperature difference of the park, comparison of cooling effect before and after completion of the park, and cooling stability, were used to evaluate the cooling effects of overall and individual parks during the construction of the new city from 2000 to 2017. We analyzed the impacts of park characteristic parameters and internal surface parameters on the cooling effects. The results showed that, from 2000 to 2017, 16 new parks were constructed in Tongzhou District, 62.5% of which had cooling effect and cooling stability, with a maximum reduction of 2.40 ℃ compared with the preconstruction. The overall cooling area and temperature difference of the parks increased significantly, whereas the cooling distance reduced. The maximum cooling distance of single park was 210 m, the maximum cooling area was 284.79 hm², the maximum cooling amplitude was 3.80 ℃, and the maximum cooling rate was 0.33 ℃·m^-1. The cooling amplitude was positively correlated with park area, while the cooling stability was positively correlated with vegetation coverage. There was a positive correlation between the cooling area and the normalized differential water index (NDWI) and park area, respectively. The impervious surface ratio (ISA) and the construction year were weakly correlated with the various cooling indicators. Our results provide a basis for the layout of parks to alleviate the overall heat island effect of the city.

Key words: park’s cooling effect, urban heat island, urban sub-center, influencing factor.