Segregation of sea breezes and cooling effects on land-surface temperatures in a coastal city

With urbanization, thermal environmental problems in coastal cities are becoming increasingly prominent. Utilizing the cooling effects of sea breezes is an effective means of solving this problem. However, current research often overlooks the compositional characteristics of sea winds, resulting in inaccurate cooling potential estimates. This study takes Shanghai, China, as the research area and proposes a novel method for regional windfield separation, which addresses the issue of previous sea-breeze calculations that neglect the daily variation of the background wind. The results showed that sea-breeze speed was relatively higher and more variable in August. When the sea-breeze speed class is below level 3 (3.4-5.4 m/s), the land-surface temperature (LST) is predominantly influenced by global warming and urbanization, whereas when it is above level 3, sea-breeze speed becomes the dominant factor. The LST within the built-up areas gradually increased when the seabreeze wind direction shifted from northeast to south. These findings help explore the potential for ocean cooling and provide valuable guidance for mitigating urban heat effects.