Weakened Sea‐Land Breeze in a Coastal Megacity Driven by Urbanization and Ocean Warming

The sea-land breeze (SLB) occurs regularly in coastal areas and influences the local climate atmospheric environment. Fifteen-year observations (2005–2019) from urban, coastal, marine stations were collected to examine trend number of SLB days (SLBD) Tianjin, a megacity China. SLBD Tianjin generally showed decreasing with an annual average decline rate 3.89%. land speed decreased by 0.20 m·s−1 sea 0.69 examined 15 years. Simultaneously, distance influence summer was reduced ∼30 km. Weather Research Forecasting model developed high-resolution use data variations surface temperature (SST) applied investigate mechanisms leading weakening SLB. increasing SST led reduction difference between land, which found be dominant factor driving summer. changes density height buildings due urbanization altered wind direction areas, turn drive during fall, while increased at night urban breeze. With projections indicating ocean warming urbanization, will become weaker occur less frequently future, probably more frequent air pollution poor ventilation cities.