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Good. Climate models have huge uncertainties in their "subgrid physics", particularly cloud formation. Subgrids physics deal with microphysics the fluid models

Good. Climate models have huge uncertainties in their "subgrid physics", particularly cloud formation. Subgrids physics deal with microphysics the fluid models cannot capture. The typical kilometer scale grids cannot capture physics and turbulence which operates on tiny scales, "butterfly effect" and all that. The standard way they deal with this uncertainty is by adding "hand tuned" parameters which are back fit to earlier imperfect climate data. Then they extrapolate to the future. But the physical basis of these terms is hand wavy at best.

mempko 7y ago
The biggest uncertainty with future predictions of the climate models isn't any inaccurate modeling of the climate system, but the modelling of the human component. Because , what warming we see in the future is really up to humanity and what we do about it. What the models CAN do is say 'look, if we do nothing this might happen , or if we do this thing, this might happen'. Helping us understand the impact of human action is their most important function imo. But really their accuracy when looking back will depend on what we do. EDIT: Are there really that many people here who don't believe humans are the ones driving global warming ?
burfog 7y ago
This sounds an awful lot like the problem of modelling the turbulent reacting flow inside a rocket engine. SpaceX did some neat work on this and presented it at a GPU conference. They did some unconventional things with the GPU, allowing variable-resolution modeling. Previously, it had not been possible to accurately model an engine because the scale required to cover the whole engine could not express the detail of the microphysics.
- swimfar 7y ago
  I remember that. Fluid dynamics is a very tricky thing to model and the work they did was really cool. There's a good video presentation on it here: https://www.youtube.com/watch?v=vYA0f6R5KAI https://www.youtube.com/watch?v=vYA0f6R5KAI
trophycase 7y ago
Good? I don't think they mean "re-examine" in the same way you mean "re-examine".

mempko 7y ago

The biggest uncertainty with future predictions of the climate models isn't any inaccurate modeling of the climate system, but the modelling of the human component. Because , what warming we see in the future is really up to humanity and what we do about it. What the models CAN do is say 'look, if we do nothing this might happen , or if we do this thing, this might happen'. Helping us understand the impact of human action is their most important function imo. But really their accuracy when looking back will depend on what we do. EDIT: Are there really that many people here who don't believe humans are the ones driving global warming ?

burfog 7y ago

This sounds an awful lot like the problem of modelling the turbulent reacting flow inside a rocket engine. SpaceX did some neat work on this and presented it at a GPU conference. They did some unconventional things with the GPU, allowing variable-resolution modeling. Previously, it had not been possible to accurately model an engine because the scale required to cover the whole engine could not express the detail of the microphysics.

swimfar 7y ago
I remember that. Fluid dynamics is a very tricky thing to model and the work they did was really cool. There's a good video presentation on it here: https://www.youtube.com/watch?v=vYA0f6R5KAI https://www.youtube.com/watch?v=vYA0f6R5KAI

trophycase 7y ago

Good? I don't think they mean "re-examine" in the same way you mean "re-examine".