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Technical milestone reached: global earth system simulations with 1.2 km resoln

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Re: Technical milestone reached: global earth system simulations with 1.2 km resoln

#41

Post by Maursault »

adrianN wrote: post #33
Maursault wrote: post #22

Earlier quoted context omitted.

If we're ever going to get to the femtometer resolution required for very precise 100 day weather forecasting, we have to start somewhere, so let them waste their time. It's not as though this is part of a growing trend to abandon conventional weather and climate modeling.

It's extremely unlikely that we'll ever get anywhere near that. Even meter precision is impractical.

Unless you know it to be physically or logically impossible, you could not really know how likely it is or isn't. Ask anyone in the mid-1970's how likely it is that billions of people would be walking around with a supercomputer in their pockets, and they'd come up with all sorts of reasons why it was extremely unlikely, such as no individual would ever need so much computing power. The practicality of the precision only depends on the ability to measure and the ability to manipulate and simulate large amounts of data, both of which are extremely likely to get better, and better faster and faster, as time and technology progresses.

Re: Technical milestone reached: global earth system simulations with 1.2 km resoln

#42

Post by Maursault »

doctor_eval wrote: post #32
Maursault wrote: post #29

Earlier quoted context omitted.

No, but I wouldn't mind weather measuments every cubic femtometer of the lower atmosphere and a fast enough computer with enough memory to cruch the data and accurately report what the weather will be like on 29 February.

Are we thinking about the same femtometer? 10^-15 of a meter? https://en.wikipedia.org/wiki/Femtometre I mean you can’t even fit a thermometer into a cubic femtometer..?

What is the smallest possible width of a photon? How do IR thermometers work without fitting them in anywhere? You just never know how it might be done.

Re: Technical milestone reached: global earth system simulations with 1.2 km resoln

#43

Post by shostack »

teraflop wrote: post #12
Victerius wrote: post #5

I have only one question. Does this mean that we are getting closer to a cloud-hosted ultimate map for games like Call of Duty and Ace Combat? I want to dogfight over Ohio, land at Offutt to play Warzone in Omaha, then take a MRAP and drive to NY.

1:1 scale multiplayer world maps have existed for decades, e.g. in Microsoft Flight Simulator. The difficulty of making a "large" map comes from what you want to simulate and in how much detail, not from how big it is per se.

And sometimes you don't need to simulate. MSFS pulls in live metar data, though previously they used Meteorblue forecast data.

Re: Technical milestone reached: global earth system simulations with 1.2 km resoln

#44

Post by kimburgess »

singularity2001 wrote: post #38

is fixed resolution really the way to go? I'd imagine big patches of the ocean and deserts being modeled as single nodes being way more efficient without compromising fidelity.

Although final output in those regions is perhaps less relevant, their state would still have an impact on other areas as the simulation progresses.

Re: Technical milestone reached: global earth system simulations with 1.2 km resoln

#45

Post by Certhas »

adamius wrote: post #40

How does such a simulation work? Eg how do hou predict the temperature at x,y? Is it ground type, water, sand?Altitude? Neighboring values thereof? What are the inputs? Do you give it a starting point and apply it to a bunch of elements like some giant automata like game of life? Some kind of finite element analysis thing? So many questions.

If only there was a way to find out...

Re: Technical milestone reached: global earth system simulations with 1.2 km resoln

#46

Post by adgjlsfhk1 »

adamius wrote: post #40

How does such a simulation work? Eg how do hou predict the temperature at x,y? Is it ground type, water, sand?Altitude? Neighboring values thereof? What are the inputs? Do you give it a starting point and apply it to a bunch of elements like some giant automata like game of life? Some kind of finite element analysis thing? So many questions.

giant partial differential equations

Re: Technical milestone reached: global earth system simulations with 1.2 km resoln

#48

Post by adgjlsfhk1 »

Maursault wrote: post #22
counters wrote: post #21

Earlier quoted context omitted.

Which is *exactly* why ultra-high resolution global weather simulation has dubious prospects for improving forecasts. When you're at spatial scales where you need to parameterize convection, there's an inherent "smoothness" to model solutions that suppresses noisy errors. If you go to cloud-resolving scales - which is needed for simulations like the ones here - you don't get the benefit of that smoothness anymore, be…

If we're ever going to get to the femtometer resolution required for very precise 100 day weather forecasting, we have to start somewhere, so let them waste their time. It's not as though this is part of a growing trend to abandon conventional weather and climate modeling.

there's a very good physical argument that this is impossible. if you want to store 1 bit per femptometer simulated, at current computer sizes, we are taking about a computer billions the size of the earth. even if you use 1 atom per bit, your computer will be almost as big as the earth. such a computer will collapse under it's own gravity.

Re: Technical milestone reached: global earth system simulations with 1.2 km resoln

#49

Post by adrianN »

Maursault wrote: post #41
adrianN wrote: post #33

Earlier quoted context omitted.

It's extremely unlikely that we'll ever get anywhere near that. Even meter precision is impractical.

Unless you know it to be physically or logically impossible, you could not really know how likely it is or isn't. Ask anyone in the mid-1970's how likely it is that billions of people would be walking around with a supercomputer in their pockets, and they'd come up with all sorts of reasons why it was extremely unlikely, such as no individual would ever need so much computing power. The practicality of the precision…

A femtometer is a few orders of magnitude smaller than an atom. There are about 2*140 atoms in the atmosphere. You can't even count to that number, let alone do any fluid dynamics to that. I'm confident that we won't have femtometer scale simulations of the atmosphere before the sun becomes a red giant and swallows the earth.

Re: Technical milestone reached: global earth system simulations with 1.2 km resoln

#50

Post by Certhas »

doctor_eval wrote: post #32
Maursault wrote: post #29

Earlier quoted context omitted.

No, but I wouldn't mind weather measuments every cubic femtometer of the lower atmosphere and a fast enough computer with enough memory to cruch the data and accurately report what the weather will be like on 29 February.

Are we thinking about the same femtometer? 10^-15 of a meter? https://en.wikipedia.org/wiki/Femtometre I mean you can’t even fit a thermometer into a cubic femtometer..?

I think Maursault has thoroughly demonstrated their lack of serious thought or reading on the subject. But just for giggles and for the casual reader, the lattice spacing of silicon is 200,000 femtometer. So if you encode only one bit per cube of this fm cubic lattice, and you manage to encode this into single atoms of silicon, you need a volume of silicon 8,000,000,000,000,000 times larger than the system you model.
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