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In climate modeling studies where the Gulf Stream was artificially swept out of existence, the temperature differences between eastern Canada and western Europe

In climate modeling studies where the Gulf Stream was artificially swept out of existence, the temperature differences between eastern Canada and western Europe persisted. Okay, so the Gulf Stream does not play any role. But then, in the very next sentence: So what’s really going on? According to Riser and Lozier, the cause of the temperature difference is likely a complex interaction between the surface ocean, the Gulf Stream, massive upper atmospheric currents and differences in pressure on either side of the Atlantic. So the Gulf Stream does get in the equation. One of these two sentences is incorrect.

whatshisface 14y ago
Maybe, in the model, the differences persisted but decreased (or increased?). Also, perhaps the model isn't given as much scientific weight as the author of the article indicated. (It's been something I have wondered about... given how hard it is for us to predict the weather, how can we possibly find long-term climate models useful?)
- Afforess 14y ago
  Climate models can be useful, especially when you use them to predict events that have already happened (e.g you have the data to either show the model is correctly forecasting the past event, or you have the data to show the model has gone awry.) Theoretically, if your model can predict past events correctly, you can then apply it to present and future events and get reasonable results. Theoretically... PS. Weather forecasting is pretty accurate these days. I'd take bets on 7 day forecasts from the NWS. Source: Meteorology degree.
  - fatbob 14y ago
    The model forecasting past events doesn't really tell you much about the accuracy of the model, even theoretically. It could be overfitting for example.
  - youngerdryas 14y ago
    Within 10 degrees F for 10 consecutive hours and precipitation to 1/4" in Boston for even money.
gruseom 14y ago
I noticed that too – that and the fact that "likely a complex interaction" sounds like an expertise-preserving way of saying "we don't know". Plus the article makes it sound like they tested the gulf stream theory by experimenting on their models, which would yield results about the models, not the reality to which the models refer.
cpleppert 14y ago
This is a blog post summarizing an article that condensed several scientific papers into a summary for popular consumption. It isn't clear in post but the sentences are referring to different competing models. The actual article suggests that the latest model where the gulf stream does play a role(but not the only one) is the correct one.
jessaustin 14y ago
Maybe the differences persisted because they were built into the model using a mechanism other than the Gulf Stream? Maybe the model was based on some other assumption that implicitly produces the differences? Models seem very easy to do poorly. They seem basically impossible to do well. The question, "how would temperature differences between North America and Europe change if the Gulf Stream ceased?" is not of a scientific nature.
- cpleppert 14y ago
  >>Models seem very easy to do poorly. They seem basically impossible to do well. Yes, insufficient understanding of the phenomena will often produce bad results. It doesn't matter whether the explanation is a model or hypothesis. Rigorous analysis and verification is required. >>The question, "how would temperature differences between North America and Europe change if the Gulf Stream ceased?" is not of a scientific nature. Thats equivalent to stating that the effect the gulf stream has on temperature differences between North America and Europe is impossible to discover scientifically.
btilly 14y ago
There is no contradiction between those sentences. The Gulf Stream contributes to those differences, but is not the only cause. Incidentally the basic explanation is obvious if you know something about climate. The powerful upper air current in question is certainly the jet stream, which at that latitude blows from west to east, and carries weather patterns with it. (The source of the jet stream is a Hadley cell.) The result is that Labrador gets weather off of land, while Europe gets weather off of the ocean. If you look at pictures from space, oceans are darker than land, and therefore absorb heat better. (This is doubly true in winter!) Thus the surface of the ocean tends to be warmer on average than land. (As well, water holds heat better, and so tends to fluctuate less. This leads to milder winters and summers.) The moral? The fact that someone doesn't try to explain something doesn't mean that they don't understand it.

whatshisface 14y ago

Maybe, in the model, the differences persisted but decreased (or increased?). Also, perhaps the model isn't given as much scientific weight as the author of the article indicated. (It's been something I have wondered about... given how hard it is for us to predict the weather, how can we possibly find long-term climate models useful?)

Afforess 14y ago
Climate models can be useful, especially when you use them to predict events that have already happened (e.g you have the data to either show the model is correctly forecasting the past event, or you have the data to show the model has gone awry.) Theoretically, if your model can predict past events correctly, you can then apply it to present and future events and get reasonable results. Theoretically... PS. Weather forecasting is pretty accurate these days. I'd take bets on 7 day forecasts from the NWS. Source: Meteorology degree.
- fatbob 14y ago
  The model forecasting past events doesn't really tell you much about the accuracy of the model, even theoretically. It could be overfitting for example.
- youngerdryas 14y ago
  Within 10 degrees F for 10 consecutive hours and precipitation to 1/4" in Boston for even money.

gruseom 14y ago

I noticed that too – that and the fact that "likely a complex interaction" sounds like an expertise-preserving way of saying "we don't know". Plus the article makes it sound like they tested the gulf stream theory by experimenting on their models, which would yield results about the models, not the reality to which the models refer.

cpleppert 14y ago

This is a blog post summarizing an article that condensed several scientific papers into a summary for popular consumption. It isn't clear in post but the sentences are referring to different competing models. The actual article suggests that the latest model where the gulf stream does play a role(but not the only one) is the correct one.

jessaustin 14y ago

Maybe the differences persisted because they were built into the model using a mechanism other than the Gulf Stream? Maybe the model was based on some other assumption that implicitly produces the differences? Models seem very easy to do poorly. They seem basically impossible to do well. The question, "how would temperature differences between North America and Europe change if the Gulf Stream ceased?" is not of a scientific nature.

cpleppert 14y ago
>>Models seem very easy to do poorly. They seem basically impossible to do well. Yes, insufficient understanding of the phenomena will often produce bad results. It doesn't matter whether the explanation is a model or hypothesis. Rigorous analysis and verification is required. >>The question, "how would temperature differences between North America and Europe change if the Gulf Stream ceased?" is not of a scientific nature. Thats equivalent to stating that the effect the gulf stream has on temperature differences between North America and Europe is impossible to discover scientifically.

btilly 14y ago

There is no contradiction between those sentences. The Gulf Stream contributes to those differences, but is not the only cause. Incidentally the basic explanation is obvious if you know something about climate. The powerful upper air current in question is certainly the jet stream, which at that latitude blows from west to east, and carries weather patterns with it. (The source of the jet stream is a Hadley cell.) The result is that Labrador gets weather off of land, while Europe gets weather off of the ocean. If you look at pictures from space, oceans are darker than land, and therefore absorb heat better. (This is doubly true in winter!) Thus the surface of the ocean tends to be warmer on average than land. (As well, water holds heat better, and so tends to fluctuate less. This leads to milder winters and summers.) The moral? The fact that someone doesn't try to explain something doesn't mean that they don't understand it.