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Japan Plans 30-Year Supercomputer Forecasts
BaltikaTroika writes "According to a ministry representative, 'Japan is planning ultra long-range 30-year weather forecasts that will predict typhoons, storms, blizzards, droughts and other inclement weather.' Maybe they should tell their secret to my local weatherman, who usually can't even get tomorrow's weather right. Whatever happened to chaos?"
Everyone is going to talk about how the buttefly effect makes this useless, and that is true for any sort of instantaneous weather. However, there are many things that affect weather cycles that are much more predictable. First is El Nino/La Nina which oscillates every few years. Then there are other oceanic oscillators that operate on a decade or longer cycle. Also there is solar output and human output. Add all of these up and you may be able to predict the frequency and severity of storms, the probablility of different weather patterns, etc. You will be able to plan for these events which will be 30 years down the road, and be able to do something about them - like build buildings capable of withstanding stronger typhoons, or rising sea levels, or what have you.
But never, in no way, will someone be able to tell you if it will rain in 3 weeks, let alone 30 years. I've studied the accuracy of forecasts quite a bit (as an energy analyst), and you can't get much better than climatology once you go 2 weeks out.
I submitted this story last night, and it didn't get posted.
It might depend where you are.
In Michigan, sure, sometimes they get a week right.
On the other hand, sometimes they're so far off you can barely recognize the week. What seems to happen is a lot of storms stall that they don't expect, or they expect something to stall and it doesn't.
Probably the funniest was the recent "hurricane" over Michigan (about a month ago), which even made Fark. This storm complex stalled for a week and change, and basically every day of the week, the prediction was that it would move away by tomorrow.
Michigan seems to be at a meeting point for storm systems coming from the West, cold air coming from Canada, and wet, moist air coming from the Gulf. Predicting which will "win" for any given day seems to give the models fits. For example, the worst winter storms for us are when the cold Canadian air meets the warm, moist Gulf air, but predicting exactly where they will meet and drop all the snow seems to have an error bar of several hundred miles (i.e., for a prediction of hitting Lansing, smack dab in the middle of the lower peninsula, you're looking at it actually hitting anywhere from mid-Ohio to the top of the UP.) I've noticed that for predicting precipitation, you're almost better off just watching a couple of hours of the radar loop and making your own prediction.
You won't be able to "predict" anything; weather is driven by a complex set of forces, of which we have a very incomplete understanding. It isn't just a matter of temperature, pressure, moisture content, UV radiation, and infrared radiation, which are the main variables your local forecaster uses to try and predict weather trends. Solar wind, ground cover, cloud formation, cosmic rays, vulcanism, atmospheric electrodynamics: these are extra variables that influence the weather in ways we can't understand. And just to screw up the mixture a bit more, add global warming.
You can build more and more sophisticated models and run them on faster and faster hardware, but in the end, you can't really account for all the possible variables to any degree of accuracy. The more variables you add, each with its own degree of accuracy, the more soupy the predictions become. We know in general terms how systems work, but we have no idea how all these forces interact to create weather. I think the Japanese should stick to trying to determine what actually drives the weather and stay out of the prediction business.
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According to this website on paleoclimatology, there are some long period weather oscillations such as:
the El Niño -Southern Oscillation (ENSO) - 6 to 18 months,
the Pacific Decadal Oscillation (PDO) - 20 to 30 years
the Pacific-North American Oscillation (PNA) - 3 to 10 years
the The North Atlantic Oscillation NAO - 5 to 10 years
the Artic Oscillation (AO)- 5 to 10 years
the Antartic Oscillation (AAO) - 5 to 10 years
Paleoclimatologists have the records of weather condifions going back thousands of years using information such as tree rings, snow, lava, and seed deposits.
If the researchers could develop a long timescale atmospheric simulator that could replicate this data, then maybe they could predict general trends 30 years into the
future. Although unpredictable events such as earthquakes and volcanos) make things
bit harder, although they will probably run a large number of possible scenarios
before making any conclusions.
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This gives me an idea for an interesting analysis. I wonder if you take all the weather predictions for the last 20 years or so and compare with the actual weather, if you'd see any patterns when you plot a map of the error as a function of location (and perhaps isolate it to the weather during a particular time of year). If there are particular locations which end up being tipping points, then that tells you something about the dynamics and where you need the highest resolution when you're building your models.
Probably someone has already done this though.