Windchill factor

We eventually reached the Pole on Day 68 of the expedition, arriving in what were becoming familiar temperatures of below -40 °C combined with winds gusting above 40 knots. The resultant windchill factor was around... 

It is well known that wind makes the cold air feel much colder as a result of the windchill effect that is due to the iii-ciease in the convection heat transfer coefficient with increasing air velocity. The windchill effect is usually expressed in terms of the windchill factor, which is ilic difference between the actual air temperature and the equivalent calm-air temperature. For example, a windchill factor of 20°C for an actual air temperature of 5°C means that the windy air at 5°C feels as cold as the still air at — 1S°C. In other words, a person will lose as much heat to air at 5°C with a windchill factor of 20 C as he or she would in calm air at — 15 C,... 

In Chapter 11, we explained the concept of windchill factors. The windchill values are determined empirically, and the common equivalent vrindchill temperature Tequivaiea, (°Q is given by... 

Windchill Factor Cooling Power of Wind on Exposed Flesh Expressed as an Equivalent Temperature (under calm conditions)... 

In Chapter 11, we explained the concept of winddull factors. We said that the heat transfer rates from your body to the surroundings increase on a cold, windy day. Simply stated, you lose more body heat on the cold, windy day than you do on a calm day. The windchill index accounts for the combined effect ofwind speed and the air temperature. It accoimts for the additional body heat loss that occurs on a cold, windy day. The windchill values are determined empirically, and a common correlation used to determine the windchill index is... 

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