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Ask Anything: Wind Chill? Heat Index? Can’t We Combine Them?

Looking into whether doing so would work.

Wind Chill? Heat Index?

Wind chill? Heat index?
Image credit: Fred Zhang/Getty Images.

In order to translate environmental conditions—how warm, cold, wet and windy it is, —into physiological risk and felt experience, almost 100 weather indices have been put forward for the last century.

Many of such indices, such as the heat index and the wind chill are targeted on specific subsets of the variables in action. For example, the heat index applies temperature and humidity while the wind chill concerns about ambient temperature and wind speed.

However, recently German meteorologist Gerd Jendritzky together with a team consisting of 45 scientists from 23 countries, have devised the index called UTCI ( the Universal Thermal Climate Index ), which was a single-number weather reading easy for estimation of the feeling an average person would have when faced with the environmental conditions.

This index would be helpful to the researchers who are intended to do a comparison of stress and mortality related with weather across large areas. Professor George Havenith of LoughboroughUniversity in England, who was co-chair of the UTCI collaboration, said that if you wanted to look at the world weather map, a single index was necessary in covering warm as well as cold.

The UTCI works like this. You should begin with measuring four local values including air temperature, relative humidity, solar radiation, and wind speed, and then you feed these values into a physiological model that takes the clothing habits in different season for an average European into consideration.

The model would help estimate the stress put on the body in regard to skin, core temperature and also sweating and then compare such stress with the strain brought on by a baseline condition. As for baseline of the model, there is neither sunshine nor wind and just with 50 percent humidity.

Although this index is not thought to be the best solution yet, however it should be the newest development so far. The scientists are eager to know that if people start with using such index, they should give their reaction towards it.

With more actual tests and feedback from users, the UTCI could become a useful and universal language in reference of climate. Wherever people travel around the world, they could look at something on the weather report and fully understand its meaning.

Source: Popular Science