Tuesday, February 10, 2004

Brrr... It's a Tad Chilly in Here, Don't You Think?
For tens of thousands of years, nobody knew how cold it was. They knew about ice and snow and the danger of freezing to death, but no one had thermometers. Instead, they used metaphors, often vulgar, to describe what the cold could do.

In the 16th century, the thermometer was invented. But it wasn't until the 18th century that Fahrenheit and Celsius came up with their numerical scales, making polite conversation about the weather possible for the first time. General satisfaction reigned, if not with the weather itself, at least with how to talk about it, until the 20th century, when the wind chill factor was invented, complicating things. The start of the 21st century has brought even more complicated attempts to describe how hot or cold it is, by academic researchers, government agencies and private companies.

Once again, nobody knows how cold it is.

The thermometer outside the kitchen window may read 20, but then a voice on the radio announces that because of the wind, humidity and a fast-moving nonsense front it feels like 127,000 degrees below zero, that in fact the entire universe has ground to a halt because of the wind chill.

When the authority of the thermometer is undermined, confusion can threaten social bonds. If two people in the same bed can say, at the same time, 'I'm freezing!' and, 'It's an oven in here,' without faith in an objective measurement, the whole point of science is called into question.

Meteorologists, aware of the crisis, are searching for a solution. The United States and Canada revised the wind chill chart a couple of years ago when critics pointed out that it had been developed using small plastic bottles of water in Antarctica. New studies used human beings in Toronto, walking on a treadmill in a cold laboratory, wind blowing in their faces.
There are so many ways to assess weather records,' he said. 'There's always a way for a weathercaster to grab a statistic.' And there's always a number for the public to puzzle over, wind chill being one of the most obvious. But despite the emphasis on the wind chill by forecasters, the index has long been known by scientists to be inadequate to the task of presenting an accurate account to the public of what the temperature feels like.
"The rule for perception of temperature she said, is, 'It depends.'

But even setting aside unpredictable variations, Dr. Bluestein said, the new chart he helped create is 'still not the definitive answer.' For instance, 'What's the influence of the sun?' That is very hard to incorporate, he said, because it depends on the time of day and latitude and longitude. RealFeel is said to incorporate the effects of sunlight, but Dr. Bluestein said without seeing the whole method described he could not comment on its accuracy.

Dr. Bluestein is on Committee 6, the international group, with Dr. Steadman of Australia and a number of other scientists. The group is pursuing a sort of nonprofit 'RealFeel,' a single number to say what the temperature feels like, summer or winter, but it has not yet come to any agreement.

Dr. Bluestein also said the perception of temperature might not depend on physiology at all. It could be related to other factors like personality, habit and custom. But, he added, the wind chill is unarguably real. One recent weekend, he said, he was visiting Chicago. 'On Friday night we went to a show,' he said. It was 6 below, supposedly, and then there was a wind. I would not go out in that weather unless I had $70 tickets.'

Dr. Bluestein emphasized that people have one common misconception about the wind chill. No matter what the chart says, neither your body nor the antifreeze in your car can get lower than the temperature when the air is still. Wind makes a body or a beaker lose heat faster than it otherwise would, but if the air temperature is 35 and the wind is 60 miles an hour, creating an equivalent temperature of 18, water will still not freeze, and frostbite is not possible.

There is, of course, a question of how much any of the scientific details matter to the average person listening to a forecast. Asked how he thought that people had responded to the wind-chill changes, Mr. Olczewski said, 'The average person doesn't seem to have noticed.'
Ah, temperature perception. It reminds me of a bi-annual phenomenon not likely unique to Minnesota. Year after year in early November and mid-to-late March there is a period of one to three weeks that although the temperature, windchill etc. are virtually identical the resultant attire is vastly different. In November, after all, you are preparing for the long, cold Winter and long pants and sweaters or jackets are in order. March however, marks Spring - well, Summer really -and the masses are out in their shorts, tanktops and sandals.


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