Thursday, January 20, 2011

The more precise, the more uncertain

I've written often in earlier blog posts about dependence on weather in planning the daily and weekly round of activities. Listening to weather forecasts on the radio when I first began coming to this island, I would plan accordingly and noticed that the weather forecasters usually, but not always, got it right. 

At some point in the 1980s I got a Weather Radio at Radio Shack and listened to the NOAA weather that was broadcast from the coastal stations. Unlike broadcast radio, the Weather Radio had the forecast available whenever you turned it on, and it was updated every six hours or so. It also included a lengthy discussion of maritime weather for those who would be in boats on the water; the whole forecast might take three minutes before it began over again. Listening to these official forecasts, particularly with their specialized ocean weather terminology, I got the feeling that forecasting was becoming more precise, although I didn't notice any improvement in accuracy. Still, I planned accordingly and most of the time things went as they were supposed to.

Beginning in the 1990s, weather forecasts became available on the Internet. Again, they were available at will. I continued hearing them on the radio, and also on the Weather Radio. I noticed that forecasters occasionally differed in their predictions, but I still took the forecasts to be "probable" and planned accordingly.

In the last decade or so, Internet sites forecasting the weather have proliferated. We have the National Weather Service, Weather Underground, Accuweather, The Weather Channel, and more. I am told that The Weather Channel in its television incarnation has turned some people into weather junkies, addicted to watching the station and hoping for exciting weather events such as floods, earthquakes, tsunamis, blizzards, tornadoes, hurricanes, and so forth. Each of the weather services boasts of the sophisticated computers it uses in forecasting the weather; and today the weather is not delivered by weathermen and women but by "meteorologists." Forecasting has become far more scientific, detailed, and precise; and it is all available at one's command, on various Internet sites.

But an unnerving thing has happened: as forecasts have become more precise, they have become more uncertain. As forecast services have proliferated, and as each one claims it is more accurate than the others, it is increasingly apparent that the forecasters do not agree. This causes anxiety and makes planning difficult. 

Forty years ago, the radio weatherman would predict a snowstorm and then most likely a storm followed. Today although all the Internet sites may predict a snowstorm, one may say that it will drop a few inches of snow and another may predict a foot. Back in the day, if a storm were predicted, one would plan to stay inside. Now, the storm can be more accurately predicted; but whose prediction is correct? The predictions depend on the differing climatic variables the forecasters input into the computer and, of course, the computer program itself. These are jealously guarded secrets.

And so today's forecasts are given with more precision but, paradoxically, the result is more uncertainty. There is more information but not all of it is consistent. All weather services may forecast a storm but one will say that it will have a low impact on travel and another that it will have a moderate or high impact. In the face of this information overload, what is a would-be traveler to do?

Heisenberg's Uncertainty Principle, as far as I can understand it, states that the more accurately one measures the position of an object, the more difficult it becomes to make an accurate measurement of its velocity. It is as if measuring the position halts the object, making it impossible to measure its speed. Some people take away from this Principle the notion that there are no good grounds for objectivity, because the observer always affects the outcome. I would go back to what I understand is its original formulation, and take away the idea that greater precision in one place leads to greater uncertainty in another. I point to contemporary weather forecasting as an example.

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