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Model Runs and variables

Model Runs and variables

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old_user134348

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Message 18005 - Posted: 10 Dec 2005, 18:53:54 UTC

I recently joined CP and know you have added variables such as sulphur into the equation but can you add any potential variables like the slowing of the gulf stream (which has slowed 30% over the past 12 years). Scientist predict that future gulf stream slowing could cool Europe by more than 1 Degree or more- Could this gulf stream variable be added to you models in the future? Could any future potential greenhouse warming could be off set by the gulf stream slowing? Some theories suggest this.
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Message 20801 - Posted: 27 Feb 2006, 14:06:39 UTC

I joined recently as well and am no expert. But since no one has replied to you, I\'ll make a comment

In the latest version of the model they are going to have the ocean modelled with a multilayered grid and this will be interacting with the atmosphere. As with the atmospheric grid, each cell will be described by parameters. In the ocean these will have to include things like the average temperature of the water in each cell, the salinity and the direction and speed of flow. If the model is sophisticated enough then the gulf stream flow should be a feature that emerges from it rather than having to be explicitely put into it.

If I understand it correctly, the gulf stream happens because as ice forms it leaves behind salt. Therefore during the winter in the arctic the formation of sea ice causes water with a higher salt concentration (and which therefore has an increased density) to sink and slide south as a deap current. This causes an equal mass of water in a surface current of warmer lower salinity water to travel north – the Gulf Stream.

So I guess the answer to your question depends on whether they have included this ice freezing–salt concentrating effect in the model. And if they haven’t, then it’s a pretty big oversight.

I’ve been pondering a similar issue regarding the melting of the arctic permafrost and the release of methane that is predicted to ensue. I suspect that this isn’t included as it means they would have to include soil dynamics and microbial activity in the model, which would complicate it a lot. Furthermore, do they include the effects of vegetation and it’s influence on dust?

Given that there seem to only a couple paid people running the project perhaps we can’t expect too much just yet.

It would be nice if they could explain the models in a bit more detail though (hint hint).
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Profile astroWX
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Message 20828 - Posted: 28 Feb 2006, 2:09:44 UTC - in response to Message 20801.  

Given that there seem to only a couple paid people running the project perhaps we can’t expect too much just yet.

It would be nice if they could explain the models in a bit more detail though (hint hint).

Have you taken the journey beginning here?
http://www.climateprediction.net/science/index.php

There are only two paid computer staff -- and they carry a heavy burden. There is also a team of PhDs and PhD candidates behind the research and you are running a million-line Fortran Model developed over 20 years by other PhDs --> and, with different resolution, runs weather forecasts for the British Met Office every day.

We are but small parts of a very large picture but, together, we constitute the largest climate prediction undertaking ever attempted.

HTH.
"We have met the enemy and he is us." -- Pogo
Greetings from coastal Washington state, the scenic US Pacific Northwest.
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Les Bayliss
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Message 20835 - Posted: 28 Feb 2006, 5:14:04 UTC

staylor
There was a THC model running for a while back in 2003/4. The results have apparently been studied and a research paper produced in 2005.
Check the Climate Science pages in the blue menu to the left of here.

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old_user156021

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Message 20839 - Posted: 28 Feb 2006, 7:56:02 UTC - in response to Message 20835.  

staylor
There was a THC model running for a while back in 2003/4. The results have apparently been studied and a research paper produced in 2005.
Check the Climate Science pages in the blue menu to the left of here.



This link leads to a description of the Thermohaline Circulation Experiment.

=> http://www.climateprediction.net/science/THC_expt.php

If I understand it correctly, the physics is not yet understood well enough to just let the thermohaline circulation emerge from the model, so they tweek it to make the circulation behave in a manner that is plausible. The experiment investigated the effects of using different values of the parameters that were tweeked.

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Questions and Answers : Wish list : Model Runs and variables

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