Contrasting impacts of urban development and broader-scale climate change on the advection effects of sea breezes based on an analysis of heat balance mechanism in urban space: A case study in Sendai, Japan

• New framework isolates urban and climate impacts on sea breeze advection effects. • Climate change amplifies sea breeze cooling more than urban development. • Climate change reduces sea breeze moisture advection more than urban development. • Quantitative evidence shows climate change drives coastal urban climate shifts. Urban development and climate change significantly alter the urban climate by modifying heat balance dynamics, but their specific impacts on sea breeze advection effects are not well understood at the city scale. To address this gap, this study introduces an analytical framework that integrates urban climate modeling with an analysis of the heat balance mechanism in urban space. Using the Weather Research and Forecasting (WRF) model, the effects of urban development were isolated by fixing the initial climate conditions, while the impacts of broader-scale climate change were examined by maintaining constant land-surface conditions. A case study in Sendai, Japan, demonstrated the accuracy of the WRF model in capturing diurnal variations in air temperature, humidity, and wind patterns. Their results revealed that urban development enhanced the cooling effect of sea breezes by 0.9%, whereas broader-scale climate change amplified this effect by 24.6%. Conversely, urban development and broader-scale climate change reduced the advection effects of sea-breeze-induced humidity by 1.3% and 32.2%, respectively. These findings quantitatively demonstrate that climate change exerts more substantial influences on sea breeze advection than urban development at the city scale. This research advances our understanding of urban-climate interactions by providing a robust and transferable tool for climate-resilient urban planning.