The interaction between urban heat island intensity and sea-breeze effect

The article investigates the interaction between the sea-breeze circulation and the urban heat island effect in Houston, Texas, located on the Gulf of Mexico coast. The analysis focuses on the summer period in 2022 during the Convective-cloud Urban Boundary-layer Experiment and the Tracking Aerosol Cloud Convection Interactions Experiment. The work, which exclusively used ground-based observations, found a high degree of intra-urban variability in both the temperature and the humidity field during the sea-breeze days. Near-surface virtual potential temperature during the sea-breeze episodes in the metropolitan area varied by almost 10 K, with urban regions near the coast experiencing lower temperature than the inland region. The urban heat island effect was strong enough to create persistent hot spots even during the sea-breeze episodes. On land-breeze days, both the temperature and the humidity fields were more uniform with little spatial variability. The depth of the sea-breeze circulation was captured using X-band radar and radiosondes; it averaged around 1500-2000 m above ground level. The thermal gradient due to the interaction between the sea-breeze circulation and the urban heat island effect led to secondary flows that influenced local convective activity. This article is part of the theme issue 'Urban heat spreading above and below ground'.