Urban infrastructure and high-rise buildings slow near-surface winds, worsening city heat

UPDATE - follow-up to Letting the wind flow freely is the secret to cooling our cities: Ground-level wind speeds in Indian cities continue to face disruptions from dense urban infrastructure, high-rise buildings, and features like high compound walls and podiums that block previously defined wind corridors.

Expert Insights

Amruthraj M.N., a consultant with the Sustainable Energy Lab at the Indian Institute for Human Settlements in Bengaluru, noted that surface-level wind speeds typically drop around 10 meters from the floor where pedestrians move. Aaron Serre, a meteorologist from the University of Alabama in Huntsville, explained that dense buildings increase surface friction and create turbulence, while replacing vegetation with concrete and asphalt reduces evapotranspiration and worsens the urban heat island effect.

Wind Phenomena

When wind hits tall buildings, it can create sheltered pockets or trigger the Venturi effect by funnelling through narrow spaces into gusts, as seen in London and Jaipur. Winds can also be forced downward in a downdraught effect. Prasad Vaidya, senior adviser at IIHS, pointed out that unplanned higher building forms contribute to lower wind speeds and extra heat stress, while Yugank Goyal from IIM Ahmedabad stressed the need for a homogenised wind record using proper anemometers.

Context

Urban microclimates are heavily shaped by physical structures and layout, which influence both heat retention and the dispersion of air pollution. City planners increasingly look at ventilation mapping and fluid dynamics simulations to better manage airflow in growing metropolitan areas.