Wind uplift - a growing concern in the urban environment?
While cities are generally perceived to reduce wind speeds due to the significant friction forces produced by building surfaces, they also add an element of unpredictability. The frictional forces create turbulence, resulting in rapid and strong changes in wind direction and speed.
Tightly packed buildings can also create urban canyons, where the wind is channelled through narrow passes, accelerating as it does so. With 84% of the UK population living in an urban environment - a figure which has increased year-on-year since 1990 - and cities becoming more densely populated, new micro-climatic considerations will impact how we design and construct our urban spaces (Satista, World Bank). One of the key considerations will be wind uplift.
Climate change is also a crucial factor. While studies show that average wind speeds appear to be falling - a trend dubbed the “global stilling” - there are regional discrepancies. For instance, some studies point towards an increase in average wind speeds in northern Europe and a fall in central Europe (GreenMatters). However, there seems to be a general agreement that there will be global increases in maximum wind speeds and the number of Category 4 and 5 storms, both of which add to the challenges associated with wind uplift (MetOffice).