Originally Posted by
Hypno Toad
From a detailed history of why wind chill is useless:
Wind Chill BlowsIt’s time to get rid of a meaningless number.
... assumptions to determine wind-chill-equivalent temperatures. Namely, they geared their calculations toward people who are 5 feet tall, somewhat portly, and walk at an even clip directly into the wind. They also left out crucial variables that have an important effect on how we experience the weather, like solar radiation. Direct sunlight can make us feel 10 to 15 degrees warmer, even on a frigid winter day. The wind chill equivalent temperature, though, assumes that we’re taking a stroll in the dead of night.
https://slate-com.cdn.ampproject.org...e-useless.html
The
paper that article references does
not say that the calculations were done on portly 5’ tall people. The Slate article is misreading the scientific paper.
For Ducharme's study, 12 adult volunteers, male and female, aged 2 2 - 4 2 with a mean of 33 years,
The only mention of 1.5m (5’) is in reference to the place where the wind speed is measured. Currently, the wind speed for wind chill calculations is measured at 10 meters (32’). The paper suggest measuring the wind speed at 1.5 meters. Perhaps that is a little low but it’s a whole lot closer to most human faces than 10m.
The Slate article is an awful article. It’s in the style of “let’s poke holes in the science” but not suggest any kind of solution.
Osczevski and Bluestein are aware of the problems. Though I am loathe to do such an extensive quotation, I think the entirety of their paper’s conclusion needs to be posted
C O N C L U S I O N. Wind chill is not a neat and simple package. A person's exposure to wind is determined by their surroundings and their activity relative to the wind direction. Time of day affects the lapse rate and the ratio of the wind at 10 m to the wind at face level, and physiology affects how they react to it. Because one's experience of the equivalent temperature depends on facial skin temperature, which varies from person to person because cheek thermal resistances vary widely, WCT is not an ideal way to express the combined effect. Wind chill is not a neat and simple package. A person's exposure to wind is determined by their surroundings and their activity relative to the wind direction. Time of day affects the lapse rate and the ratio of the wind at 10 m to the wind at face level, and physiology affects how they react to it. Because one's experience of the equivalent temperature depends on facial skin temperature, which varies from person to person because cheek thermal resistances vary widely, WCT is not an ideal way to express the combined effect of wind and low temperature. Ideally, an index of wind chill should be invariant with respect to individual differences or stated so that it can be individually cali- brated with experience, as was the original three- or four-digit Wind Chill Index that Siple and Passel (1945) created. However, the public seems to have a strong preference for the equivalent temperature format (Maarouf and Bitzos 2000), a deceptive simplification that only seems to be easier to understand.
Wind chill is an evolving concept. Wind chill equivalent temperature charts might someday include solar heating effects; improved prediction of time to frostbite and more sophisticated time-dependent models of skin cooling in wind. The short-term effects of wind chill are of interest, as many people in the modern world are not exposed to the wind for long enough to reach a steady-state skin temperature. Consideration might also be given to modifying the assumed value of internal thermal resistance to tailor the chart more directly to the average person. An up- ward adjustment of the steady-state core temperature and minimum wind speed could result in a chart that applies more directly to people engaged in tasks that have moderately high rates of energy expenditure, such as recreational cross-country skiers or runners. Another niche calculation might be a marine wind chill chart, incorporating the cooling effects of fog or spray. It seems unlikely that another half century will go by before wind chill is again upgraded.
They realize there are problems with the popular version of “wind chill factor”. Unlike the Slate article, they do suggest some changes.