Remote sensing technologies provide glimpse into urban airflow dynamics
Remote sensing technologies provide glimpse into urban airflow dynamics lead image
Modern cities are large enough to have their own weather and climates, but the effects of urban structures on the atmosphere are still not thoroughly understood. Part of the challenge is establishing monitoring networks at multiple levels across an urban skyline. Recent technologies, like lidar and microwave radiometers, have the potential to simplify this task.
He et al. employed these remote sensing technologies to study the urban atmospheric boundary layer (ABL) in Hong Kong. Their data offers insights into airflow in the city and could be used to inform simulations and guide urban developments.
The authors employed both lidar and radiometers to collect data on atmospheric stability, ABL height, wind shear, and wind veer during a one-year period. They found frequent unstable conditions, impacting changes in wind speed and direction at different altitudes.
“Our most important conclusions are that statically unstable stratification is prevalent at the urban site, with a probability of about 85%, and that wind speed and direction profiles significantly vary with atmospheric stability, with the wind shear exponent and wind veer angle generally increasing with stability,” said author Junyi He.
These results could help experts design more wind-resistant buildings and plan cities to better disperse heat and airborne pollution.
“One of the next steps is to expand the observational network to cover more sites in different terrain conditions,” said He. “For example, one possible site in Hong Kong to deploy remote sensing instruments is the coastal site Siu Ho Wan. A very important phenomenon, the urban heat island effect, could be investigated based on the simultaneous observations from this urban site and the coastal site.”
Source: “Observation of wind and thermodynamic structure within an urban boundary layer,” by J. Y. He, P. W. Chan, Z. F. Liu, J. C. H. Fung, and Q. S. Li, Physics of Fluids (2024). The article can be accessed at https://doi.org/10.1063/5.0214961 .
This paper is part of the Flow and Civil Structures Collection, learn more here .
