Of course the completeness of the data leaves a lot to be desired. None of the North Slope stations have ever recorded a wind chill lower than the -96☏ in January 1989 at Prudhoe Bay. I did some digging around at the NOAA hourly observation site and decided to download all data for stations on the North Slope. In addition, the New and Old windchill values are displayed. ![]() Air temperature, wind, and wind gust values are displayed. The New method also takes into account the attenuation of wind from the standard measurement height to the space that people occupy.įig 3. However, for low wind speeds, the New method produces slightly colder values since it assumes that the observer is walking at 1.5 m/s. In general, the New method's values are warmer than the Old values for most wind speeds. A comparison between the two formulas at 5☏ is shown in Figure 1. Clearly temperatures lower than -40☏ occur frequently in Alaska. The equation, however, can be used for any temperature and any wind speed. The air temperature in the original table ranged from +45☏ to -40☏. The New wind chill formula is actually an equation that was derived from a table with approximately 800 cells based on the wind tunnel experiments noted earlier. Due to some glaring shortcomings with the application of the 1945 study to human perception, a series of wind tunnel experiments were conducted and a New Wind Chill Index was formulated and implemented by the NWS in 2001. ![]() The study was not intended to determine equivalent temperatures but it was used for that purpose nonetheless and thus the Wind Chill Index (WCI) was born. ![]() The Old method was based on a study in 1945 that measured how long it took for water to freeze in various temperature and wind conditions in Antarctica. As most readers of this blog know, the formula for calculating wind chill changed in 2001 (a good description of the new formula and the rationale behind the change cane be found here).
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