All’s fair in wind and snow? Correcting for wind conditions in high-performance sports
by Guy Larose
Ski jumpers fly—literally. They position their bodies and skis to become airfoils, creating aerodynamic lift that help them sail for 200 meters and more, or roughly the length of a city block (about 650 feet). So like any object that experiences lift, ski jumpers are affected by the wind. To make things fairer for jumpers—though maybe less exciting for spectators—the sport introduced a calculated score correction for wind conditions.
Today, ski jumping is the only Olympic sport that directly corrects scores in international competition based on wind conditions. But as winning margins continue to tighten in world-class competitions, I expect these kinds of corrections to be considered in other sports.
Because we’re in the midst of the 2018 Winter Olympics, events such as alpine skiing, cross-country skiing, snowboard big-air, biathlon, and free-style skiing aerial come to mind as sports where winds would influence the outcome. Summer sports are moving this way too. For example, track and field, sprint and discus events already record wind conditions, although scores are not adjusted, and in tennis, wind is factored into the imaging technology that calls shots in or out.
At RWDI, as world-class specialists in modelling and testing the effects of wind, we spend a lot of time thinking about the right way to measure and compensate for wind. Recently, we’ve started looking at the factors that would go into building scientifically accurate wind corrections for high-performance sports.
There are two main areas where wind can affect performance: equipment and the field of play. I’ve talked about how wind analysis can be used to improve speed skating gear in another post. Here I’ll focus on the field of play.
In an ideal world, a correction would be customized to the event site. Each location has its own “personalized” winds. This “wind profile” is determined by a combination of factors, such as speed, direction, turbulence and frequency of each condition. We also know from our detailed study of local climates and terrains that climate microzones can form in unexpected places. Because of these microzones, conditions can change greatly over a few kilometers or even meters. For this reason, it’s important to use care when choosing locations for meteorological monitoring stations. To get a true correction, we would study a model of the competition site and its surroundings in a wind tunnel, and then add in statistical profiles of the typical local atmospheric conditions. However, even without specifics of a site, we could use more general principles of wind behavior to develop scientifically rigorous corrections.
There are further considerations depending on the sport. How do we know the correction is true for the whole course? What if conditions at the bottom of the alpine run are different from those at the top? Is the middle of the course windier than the sides? How do wind conditions contribute to the quality of the snow surface?
So far, all these questions have mostly been left to the magic realm of “luck.” As spectators and as amateur athletes, the luck factor can be a big part of the thrill of sports.
But as we pursue a different thrill—pushing the limits of human ability—part of the challenge is to define and answer those questions rigorously. If that’s a direction you want to go, call us; this challenge is our work, every day.